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Sample records for stress-true strain curves

  1. Material Properties Test to Determine Ultimate Strain and True Stress-True Strain Curves for High Yield Steels

    Energy Technology Data Exchange (ETDEWEB)

    K.R. Arpin; T.F. Trimble

    2003-04-01

    This testing was undertaken to develop material true stress-true strain curves for elastic-plastic material behavior for use in performing transient analysis. Based on the conclusions of this test, the true stress-true strain curves derived herein are valid for use in elastic-plastic finite element analysis for structures fabricated from these materials. In addition, for the materials tested herein, the ultimate strain values are greater than those values cited as the limits for the elastic-plastic strain acceptance criteria for transient analysis.

  2. Atlas of stress-strain curves

    CERN Document Server

    2002-01-01

    The Atlas of Stress-Strain Curves, Second Edition is substantially bigger in page dimensions, number of pages, and total number of curves than the previous edition. It contains over 1,400 curves, almost three times as many as in the 1987 edition. The curves are normalized in appearance to aid making comparisons among materials. All diagrams include metric (SI) units, and many also include U.S. customary units. All curves are captioned in a consistent format with valuable information including (as available) standard designation, the primary source of the curve, mechanical properties (including hardening exponent and strength coefficient), condition of sample, strain rate, test temperature, and alloy composition. Curve types include monotonic and cyclic stress-strain, isochronous stress-strain, and tangent modulus. Curves are logically arranged and indexed for fast retrieval of information. The book also includes an introduction that provides background information on methods of stress-strain determination, on...

  3. Progress Report on Alloy 617 Isochronous Stress-Strain Curves

    Energy Technology Data Exchange (ETDEWEB)

    Jill K. Wright; Richard N. Wright; Nancy J. Lybeck

    2014-03-01

    Isochronous stress-strain curves for Alloy 617 up to a temperature of 1000°C will be required to qualify the material for elevated temperature design in Section III, Division 1, Subsection NH of the ASME Boiler and Pressure Vessel Code. Several potential methods for developing these curves are reviewed in this report. It is shown that in general power-law creep is the rate controlling deformation mechanism for a wide range of alloy heats, test temperatures and stresses. Measurement of the strain rate sensitivity of Alloy 617 indicates that the material is highly strain rate sensitive in the tensile deformation range above about 750°C. This suggests that the concept of a hot tensile curve as a bounding case on the isochronous stress-strain diagrams is problematic. The impact of strain rate on the hot tensile curves is examined and it is concluded that incorporating such a curve is only meaningful if a single tensile strain rate (typically the ASTM standard rate of 0.5%/min) is arbitrarily defined. Current experimentally determined creep data are compared to isochronous stress-strain curves proposed previously by the German programs in the 1980s and by the 1990 draft ASME Code Case. Variability in how well the experimental data are represented by the proposed design curves that suggests further analysis is necessary prior to completing a new draft Code Case.

  4. A NURBS approximation of experimental stress-strain curves

    International Nuclear Information System (INIS)

    Fedorov, Timofey V.; Morrev, Pavel G.

    2016-01-01

    A compact universal representation of monotonic experimental stress-strain curves of metals and alloys is proposed. It is based on the nonuniform rational Bezier splines (NURBS) of second order and may be used in a computer library of materials. Only six parameters per curve are needed; this is equivalent to a specification of only three points in a stress-strain plane. NURBS-functions of higher order prove to be surplus. Explicit expressions for both yield stress and hardening modulus are given. Two types of curves are considered: at a finite interval of strain and at infinite one. A broad class of metals and alloys of various chemical compositions subjected to various types of preliminary thermo-mechanical working is selected from a comprehensive data base in order to test the methodology proposed. The results demonstrate excellent correspondence to the experimental data. Keywords: work hardening, stress-strain curve, spline approximation, nonuniform rational B-spline, NURBS.

  5. Stress strain flow curves for Cu-OFP

    International Nuclear Information System (INIS)

    Sandstroem, Rolf; Hallgren, Josefin

    2009-04-01

    Stress strain curves of oxygen free copper alloyed with phosphorus Cu-OFP have been determined in compression and tension. The compression tests were performed at room temperature for strain rates between 10 -5 and 10 -3 1/s. The tests in tension covered the temperature range 20 to 175 deg C for strain rates between 10 -7 and 5x10 -3 1/s. The results in compression and tension were close for similar strain rates. A model for stress strain curves has been formulated using basic dislocation mechanisms. The model has been set up in such a way that fitting of parameters to the curves is avoided. By using a fundamental creep model as a basis a direct relation to creep data has been established. The maximum engineering flow stress in tension is related to the creep stress giving the same strain rate. The model reproduces the measured flow curves as function of temperature and strain rate in the investigated interval. The model is suitable to use in finite-element computations of structures in Cu-OFP

  6. Stress-Strain Curves for High-Performance Fiber Reinforced ...

    African Journals Online (AJOL)

    Steel fiber reinforced concrete (SFRC) is increasingly being used day by day as a structural material for various applications. The complete stress-strain curve of this material in compression is needed for the analysis and design of structural elements. An experimental investigation was carried out to generate the complete ...

  7. Representative Stress-Strain Curve by Spherical Indentation on Elastic-Plastic Materials

    Directory of Open Access Journals (Sweden)

    Chao Chang

    2018-01-01

    Full Text Available Tensile stress-strain curve of metallic materials can be determined by the representative stress-strain curve from the spherical indentation. Tabor empirically determined the stress constraint factor (stress CF, ψ, and strain constraint factor (strain CF, β, but the choice of value for ψ and β is still under discussion. In this study, a new insight into the relationship between constraint factors of stress and strain is analytically described based on the formation of Tabor’s equation. Experiment tests were performed to evaluate these constraint factors. From the results, representative stress-strain curves using a proposed strain constraint factor can fit better with nominal stress-strain curve than those using Tabor’s constraint factors.

  8. Strain Rate Effects, Transition Behaviour and Master Curve Concept

    Czech Academy of Sciences Publication Activity Database

    Dlouhý, Ivo; Pluvinage, G.; Holzmann, Miloslav

    č. 8 (2004), s. IV 16-IV 22 ISSN 1291-8199 R&D Projects: GA AV ČR IAA2041003; GA ČR GA106/01/0342 Institutional research plan: CEZ:AV0Z2041904 Keywords : ferritic steel * pressure vessel steel * master curve Subject RIV: JL - Materials Fatigue, Friction Mechanics

  9. Universal scaling of the stress-strain curve in amorphous solids.

    Science.gov (United States)

    Lin, Jie; Zheng, Wen

    2017-09-01

    The yielding transition of amorphous solids is a phase transition with a special type of universality. Critical exponents and scaling relations have been defined and proposed near the yield stress. We show here that, even in the initial stage of shear far below the yield stress, the stress-strain curve of amorphous solids also shows critical scaling with universal exponents. The key point is to remove the elastic part of the strain, and the shear stress exhibits a sublinear scaling with the plastic strain. We show how this critical scaling is related to the finite size effect of the minimum strain to trigger the first plastic avalanche after a quench. We point out that this sublinear scaling between the stress and the plastic strain implies the divergence of a high-order shear modulus. A scaling relation is derived between two exponents characterizing the stress-strain curve and the density distribution of the local stabilities, respectively. We test the critical scaling of the stress-strain curve using both mesoscopic and atomistic simulations and get satisfying agreement in two and three dimensions.

  10. Cyclic stress-strain curve for low cycle fatigue design and development of small specimen technology

    International Nuclear Information System (INIS)

    Nishimura, A.; Nogami, S.; Wakai, Eiichi

    2012-11-01

    A blanket system in DEMO requires a low cycle fatigue design because higher inner pressure will act on a structural wall. An importance of cyclic stress-strain curve is investigated and necessity reason for a precise deformation measurement is discussed. Since a small specimen technique is necessary to investigate neutron irradiation effect, it is desired to establish a test procedure to obtain the stress-strain curve with small specimens. To do this, a new test procedure with nanometer scale resolution was developed and some data were obtained. (author)

  11. Construction of stess-strain curves for brittle materials by indentation in a wide temperature range

    Directory of Open Access Journals (Sweden)

    Milman Yu.V.

    2007-01-01

    Full Text Available A test method procedure for constructing stress-strain curves by indentation of brittle and low plastic materials under temperature ranging from 20 to 900°C was developed recently by Yu. Milman, B. Galanov et al. According to this test method procedure stress-strain curves σ - Є for Si, Ge, SiC, TiB2 and WC/Co hard alloy were constructed in the above temperature region and mechanical parameters such as elastic point, σe, yield stress, σs, etc. were extracted by using the measurement results obtained by a set of trihedral pyramid indenters with different angles at the tip, γ1, ranging from 45 to 85°C.

  12. Investigation of pipe strain measurements in a curved wide plate specimen

    Energy Technology Data Exchange (ETDEWEB)

    Hertele, Stijn [FWO Flanders Aspirant, Laboratory Soete, Ghent University (Belgium)], email: Stijn.Hertele@UGent.be; Waele, Wim De; Denys, Rudi; Van Wittenberghe, Jeroen; Verstraete, Matthias [Laboratory Soete, Ghent University (Belgium)

    2010-07-01

    The curved wide plate (CWP) test consists of a tensile test on an unflattened pipe containing a defective weld and it permits to determine the strain capacity. This test has been massively used for determining defective girth weld strain capacity for the last 2 decades. However this test is still not standardized and the impacts of the specimen geometry and deformation measurement setup on the measurement are still unknown; evaluating these impacts is the aim of this paper. The CWP was modeled with a parametric Python script and a finite element analysis was performed with ABAQUS 6.8 software. Results of the finite element analysis showed that if the UGent guidelines are followed, the geometry of the CWP has little influence on the measurements. This study highlighted that following the UGent guidelines ensures that the measurement of the defective girth weld strain capacity will not depend on the specimen geometry.

  13. Observations of stress-strain curves of hcp-Fe at high pressures and temperatures

    Science.gov (United States)

    Nishiyama, N.; Wang, Y.; Rivers, M. L.; Sutton, S. R.

    2005-12-01

    We performed in-situ X-ray diffraction and radiography experiments of hcp-Fe within its stability field to observe some independent stress-strain curves of this material. Deformation experiments were carried out at the GSECARS 13-BM-D beamline (APS) using a deformation-DIA with a monochromatic X-ray diffraction and a radiographic imaging system. We used four tungsten carbide and two sintered diamond (SD) anvils with truncated edge length of 2 mm. Pressure medium was a mixture of boron and epoxy and a cylindrical graphite furnace was employed. The starting material is a fragment of pure bcc-Fe wire (0.5 mm in diameter and 0.5 mm long) and two deformation pistons made of alumina were situated above and below the sample. First, the cell assembly was compressed uniformly at room temperature up to about 13 GPa. After that, the sample was heated to about 700 K and we observed transformation of the sample to hcp-Fe. Several deformation cycles were repeated at high pressures and temperatures after the transformation. The incident beam was directed through an anvil-gap and impinged the sample. The diffracted X-rays went through the SD anvils, and thus we were able to observe diffraction Debye rings over the entire 360 degrees detector azimuth range. Two-dimensional diffraction patterns were collected using an X-ray CCD detector. Using distortion of the Debye rings from the true circle and single-crystal elastic moduli of hcp-Fe, differential stresses can be calculated. The sample length was measured by radiography using a wide X-ray beam. Using the radiographic data, axial strains of the sample can be determined. We observed ten independent stress-strain curves with pressures of about 12 GPa, axial strains in excess of 15 percent, three different temperatures, and some strain rates. These stress-strain curves indicate that hcp-Fe deforms elastically at the beginning of deformation. In some of these, we observed saturation of the sample stresses, which means that the

  14. Modeling two strains of disease via aggregate-level infectivity curves.

    Science.gov (United States)

    Romanescu, Razvan; Deardon, Rob

    2016-04-01

    Well formulated models of disease spread, and efficient methods to fit them to observed data, are powerful tools for aiding the surveillance and control of infectious diseases. Our project considers the problem of the simultaneous spread of two related strains of disease in a context where spatial location is the key driver of disease spread. We start our modeling work with the individual level models (ILMs) of disease transmission, and extend these models to accommodate the competing spread of the pathogens in a two-tier hierarchical population (whose levels we refer to as 'farm' and 'animal'). The postulated interference mechanism between the two strains is a period of cross-immunity following infection. We also present a framework for speeding up the computationally intensive process of fitting the ILM to data, typically done using Markov chain Monte Carlo (MCMC) in a Bayesian framework, by turning the inference into a two-stage process. First, we approximate the number of animals infected on a farm over time by infectivity curves. These curves are fit to data sampled from farms, using maximum likelihood estimation, then, conditional on the fitted curves, Bayesian MCMC inference proceeds for the remaining parameters. Finally, we use posterior predictive distributions of salient epidemic summary statistics, in order to assess the model fitted.

  15. STRESS - STRAIN CURVE ANALYSIS OF WOVEN FABRICS MAD E FROM COMBED YARNS TYPE WOOL

    Directory of Open Access Journals (Sweden)

    VÎLCU Adrian

    2014-05-01

    Full Text Available The paper analyses the tensile behavior of woven fabrics made from 45%Wool + 55% PES used for garments. Analysis of fabric behavior during wearing has shown that these are submitted to simple and repeated uni-axial or bi-axial tensile strains. The level of these strains is often within the elastic limit, rarely going over yielding. Therefore the designer must be able to evaluate the mechanical behavior of such fabrics in order to control the fabric behavior in the garment. This evaluation is carried out based on the tensile testing, using certain indexes specific to the stress-strain curve. The paper considers an experimental matrix based on woven fabrics of different yarn counts, different or equal yarn count for warp and weft systems and different structures. The fabrics were tested using a testing machine and the results were then compared in order to determine the fabrics’ tensile behavior and the factors of influence that affect it.From the point of view of tensile testing, the woven materials having twill weave are preferable because this type of structure is characterized by higher durability and better yarn stability in the fabric. In practice, the woven material must exhibit an optimum behavior to repeated strains, flexions and abrasions during wearing process. The analysis of fabrics tensile properties studied by investigation of stress-strain diagrams reveals that the main factors influencing the tensile strength are: yarns fineness, technological density of those two systems of yarns and the weaving type.

  16. Stress-strain curve of concretes with recycled concrete aggregates: analysis of the NBR 8522 methodology

    Directory of Open Access Journals (Sweden)

    D. A. GUJEL

    Full Text Available ABSTRACT This work analyses the methodology "A" (item A.4 employed by the Brazilian Standard ABNT 8522 (ABNT, 2008 for determining the stress-strain behavior of cylindrical specimens of concrete, presenting considerations about possible enhancements aiming it use for concretes with recycled aggregates with automatic test equipment. The methodology specified by the Brazilian Standard presents methodological issues that brings distortions in obtaining the stress-strain curve, as the use of a very limited number of sampling points and by inducing micro cracks and fluency in the elastic behavior of the material due to the use of steady stress levels in the test. The use of a base stress of 0.5 MPa is too low for modern high load test machines designed do high strength concrete test. The work presents a discussion over these subjects, and a proposal of a modified test procedure to avoid such situations.

  17. Forming limit curves determined in high-speed Nakajima tests and predicted by a strain rate sensitive model

    Science.gov (United States)

    Weiß-Borkowski, Nathalie; Lian, Juhne; Marten, Thorsten; Tröster, Thomas; Münstermann, Sebastian; Bleck, Wolfgang

    2017-10-01

    Material characteristics such as yield strength and failure strain are affected by the loading speed. Even the start of instability and necking depends not only on the strain hardening coefficient but also on the strain rate sensitivity parameter. Therefore, the strain rate dependence of materials for both plasticity and the failure behavior is taken into account in crash simulations for strain rates up to 1,000 s-1. The current standard experiment for investigation of strain rate dependence is the high speed tensile test as described in a FAT guideline. Moreover, the need of material characterization at multi-axial loadings and high strain rates is pointed out in FAT guideline. Forming limit diagrams (FLD) can be used for the description of the material`s instability behavior at multi-axial loading. Usually, the FLD are determined quasi-statically at 1.5 mm/s. The usage of experimentally determined, quasi-static FLD also at high strain rates leads to great uncertainties and thus can be hardly used in crash simulations. A possibility for experimentally recording FLD at high forming rates > 100 s-1 offers the present described high speed Nakajima test. The results for the deep drawing steel DC01 illustrate the need of the determination of dynamic FLD. In this context, due to the strain rate dependence of the material behavior an extrapolation of quasi-static FLD is not feasible. Alternatively, the prediction of forming limit curves (FLC) at high strain rates is possible with the extended modified maximum force criterion. This new and extended model includes the strain rate dependence and therefore predicting forming limits at dynamic forming gets possible. The new approach is described and the accordance of experimental determined and predicted results for the begin of instability is presented.

  18. Double-curved textile reinforced concrete panels with tensile strain-hardening characteristics

    NARCIS (Netherlands)

    Kok, M.; Schipper, H.R.; Grunewald, S.; Nijsse, R.

    2014-01-01

    The construction of buildings with fi-ee-form surfaces can be accompanied with relatively high costs. An innovative method to produce free-form surfaces in concrete is the application of double-curved precast panels produced with a flexible re-usable mould technique. Traditional placing of

  19. Killing curve activity of ciprofloxacin is comparable to synergistic effect of beta-lactam-tobramycin combinations against Haemophilus species endocarditis strains

    DEFF Research Database (Denmark)

    Westh, H; Frimodt-Møller, N; Gutschik, E

    1992-01-01

    Nine Haemophilus species strains, all beta-lactamase negative, isolated from patients with endocarditis were tested in killing curve experiments. Antibiotics used were penicillin, amoxicillin, aztreonam alone and in combination with tobramycin, as well as ciprofloxacin alone. Synergism between beta...

  20. Influence of phosphorus on the tensile stress strain curves in copper

    International Nuclear Information System (INIS)

    Sandström, Rolf

    2016-01-01

    Copper canisters are planned to be used for final disposal of spent nuclear fuel in Sweden. The canisters will be exposed to slow plastic straining over extensive periods of time. To be able to predict the mechanical properties a range of basic models have previously been developed for copper with and without phosphorus (Cu-OFP, Cu-OF). Already with the small amount of phosphorus added in the canisters (60 wt. ppm) dramatic improvements in the measured creep strength and the creep ductility are found. The basic models are further developed in the present paper. The influence of phosphorus on slow strain rate tests is analysed. It is shown that the main effect of phosphorus is that it prevents brittle rupture, which is modelled by taking creep cavitation into account.

  1. Modification of the Stress-Strain Curve for High-Strength Line Pipe Steel

    Science.gov (United States)

    Jonsson, Katherine

    2013-01-01

    This thesis presents work performed to improve the work hardening behaviour of an X80 microalloyed steel through various Interrupted Thermal Treatments (ITT). The aim of this work was to determine the relationships between thermal history, microstructure and mechanical properties through both qualitative and quantitative measures. Prior to the ITT experiments, a continuous cooling transformation (CCT) diagram was constructed under no-strain conditions to identify the transformation temperatures and products that are achievable in X80 steel. The thermal treatments were applied using a Gleeble thermal-mechanical simulator to generate a variety of microstructures in various fractions and morphologies. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to investigate and quantify the microstructures in terms of phase fraction and grain size. The ITT experiments successfully generated microstructures comprised of ferrite, bainitic ferrite, martensite and martensite-austenite (M-A) without the addition of strain. The effect of cooling rates, interrupt temperature, re-heat temperature and hold times were investigated and the mechanical performance was correlated with the quantified microstructures. Although the ITT experiments did not improve the strength relative to a continuously cooled sample, the work hardening coefficient was increased as a result of the interrupted thermal treatments.

  2. Evaluation of the Capacity of PCR and High-Resolution Melt Curve Analysis for Identification of Mixed Infection with Mycoplasma gallisepticum Strains.

    Directory of Open Access Journals (Sweden)

    Seyed A Ghorashi

    Full Text Available Pathogenicity and presentation of Mycoplasma gallisepticum (MG infection may differ from one strain to another and this may have implications on control measures. Infection of individual birds with more than one MG strain has been reported. A PCR followed by high resolution melt (HRM curve analysis has been developed in our laboratory and routinely used for detection and differentiation of MG strains. However the potential of this test for identification of MG strains in a mixed specimen has not been evaluated. In the present study, the capability of PCR-HRM curve analysis technique, targeting vlhA and pvpA genes was assessed for identification of individual MG strains in a mixed population. Different DNA ratios of two MG strains from 1 to 10(-4 ng were tested with some generated conventional and normalized curves distinct from those of individual strains alone. Using genotype confidence percentages (GCP generated from HRM curve analysis, it was found that vlhA PCR-HRM was more consistent than pvpA PCR-HRM for the detection of MG ts-11 vaccine strain mixed with any of the MG strains 6/85, F, S6 or a field isolate. The potential of vlhA PCR-HRM to detect mixed MG strains in a specimen was found to be primarily dependent on quantity and proportion of the target DNAs in the mixture. This is the first study examining the capacity of PCR-HRM technique for identification of individual MG strains in a mixed strain population.

  3. Killing curve activity of ciprofloxacin is comparable to synergistic effect of beta-lactam-tobramycin combinations against Haemophilus species endocarditis strains

    DEFF Research Database (Denmark)

    Westh, H; Frimodt-Møller, N; Gutschik, E

    1992-01-01

    Nine Haemophilus species strains, all beta-lactamase negative, isolated from patients with endocarditis were tested in killing curve experiments. Antibiotics used were penicillin, amoxicillin, aztreonam alone and in combination with tobramycin, as well as ciprofloxacin alone. Synergism between beta......-lactams and tobramycin with reduction of colony counts to zero was seen after 24 h for H. influenzae, H. parainfluenzae and H. segnis strains. Ciprofloxacin was as effective as beta-lactam-tobramycin combinations. The H. aphrophilus strain was not killed as effectively as other strains by any of the antibiotics....

  4. The nonlinear Maxwell-type model for viscoelastoplastic materials: simulation of temperature influence on creep, relaxation and strain-stress curves

    Directory of Open Access Journals (Sweden)

    Andrew V. Khokhlov

    2017-04-01

    Full Text Available The nonlinear Maxwell-type constitutive relation with two arbitrary material functions for viscoelastoplastic multi-modulus materials is studied analytically in uniaxial isothermic case to reveal the model abilities and applicability scope and to develop techniques of its identification, tuning and fitting. The constitutive equation is aimed at adequate modeling of the rheological phenomena set which is typical for reonomic materials exhibiting non-linear hereditary properties, strong strain rate sensitivity, secondary creep, yielding at constant stress, tension compression asymmetry and such temperature effects as increase of material compliance, strain rate sensitivity and rates of dissipation, relaxation, creep and plastic strain accumulation with temperature growth. The model is applicable for simulation of mechanical behaviour of various polymers, their solutions and melts, solid propellants, sand-asphalt concretes, composite materials, titanium and aluminum alloys, ceramics at high temperature and so on. To describe the influence of temperature on material mechanical behavior (under isothermic conditions, two scalar material parameters of the model (viscosity coefficient and “modulus of elasticity” are considered as a functions of temperature level. The general restrictions on their properties which are necessary and sufficient for adequate qualitative description of the basic thermomechanical phenomena related to typical temperature influence on creep and relaxation curves, creep recovery curves, creep curves under step-wise loading and quasi-static stress-strain curves of viscoelastoplastic materials are obtained. The restrictions are derived using systematic analytical study of general qualitative features of the theoretic creep and relaxation curves, creep curves under step-wise loading, long-term strength curves and stress-strain curves at constant strain or stress rates generated by the constitutive equation (under minimal

  5. Investigation Study on Determination of Fracture Strain and Fractuer Forming Limit Curve Using Different Experimental and Numerical Methods

    Science.gov (United States)

    Farahnak, P.; Urbanek, M.; Džugan, J.

    2017-09-01

    Forming Limit Curve (FLC) is a well-known tool for the evaluation of failure in sheet metal process. However, its experimental determination and evaluation are rather complex. From theoretical point of view, FLC describes initiation of the instability not fracture. During the last years Digital Image Correlation (DIC) techniques have been developed extensively. Throughout this paper, all the measurements were done using DIC and as it is reported in the literature, different approaches to capture necking and fracture phenomena using Cross Section Method (CSM), Time dependent Method (TDM) and Thinning Method (TM) were investigated. Each aforementioned method has some advantages and disadvantages. Moreover, a cruciform specimen was used in order to cover whole FLC in the range between uniaxial to equi-biaxial tension and as an alternative for Nakajima test. Based on above-mentioned uncertainty about the fracture strain, some advanced numerical failure models can describe necking and fracture phenomena accurately with consideration of anisotropic effects. It is noticeable that in this paper, dog-bone, notch and circular disk specimens are used to calibrate Johnson-Cook (J-C) fracture model. The results are discussed for mild steel DC01.

  6. Evaluation of Strain-Life Fatigue Curve Estimation Methods and Their Application to a Direct-Quenched High-Strength Steel

    Science.gov (United States)

    Dabiri, M.; Ghafouri, M.; Rohani Raftar, H. R.; Björk, T.

    2018-03-01

    Methods to estimate the strain-life curve, which were divided into three categories: simple approximations, artificial neural network-based approaches and continuum damage mechanics models, were examined, and their accuracy was assessed in strain-life evaluation of a direct-quenched high-strength steel. All the prediction methods claim to be able to perform low-cycle fatigue analysis using available or easily obtainable material properties, thus eliminating the need for costly and time-consuming fatigue tests. Simple approximations were able to estimate the strain-life curve with satisfactory accuracy using only monotonic properties. The tested neural network-based model, although yielding acceptable results for the material in question, was found to be overly sensitive to the data sets used for training and showed an inconsistency in estimation of the fatigue life and fatigue properties. The studied continuum damage-based model was able to produce a curve detecting early stages of crack initiation. This model requires more experimental data for calibration than approaches using simple approximations. As a result of the different theories underlying the analyzed methods, the different approaches have different strengths and weaknesses. However, it was found that the group of parametric equations categorized as simple approximations are the easiest for practical use, with their applicability having already been verified for a broad range of materials.

  7. Identification of a new genetic marker in Mycoplasma synoviae vaccine strain MS-H and development of a strategy using polymerase chain reaction and high-resolution melting curve analysis for differentiating MS-H from field strains.

    Science.gov (United States)

    Zhu, Ling; Konsak, Barbara M; Olaogun, Olusola M; Agnew-Crumptona, Rebecca; Kanci, Anna; Marenda, Marc S; Browning, Glenn F; Noormohammadi, Amir H

    2017-10-01

    Mycoplasma synoviae (MS) is an economically important avian pathogen worldwide, causing subclinical respiratory tract infection and infectious synovitis in chickens and turkeys. A temperature-sensitive (ts + ) live attenuated vaccine MS-H, derived from the Australian field strain 86079/7NS, is now widely used in many countries to control the disease induced by MS. Differentiation of MS-H vaccine from field strains is crucial for monitoring vaccination programs in commercial poultry. Comparison of genomic sequences of MS-H and its parent strain revealed an adenine deletion at nucleotide position 468 of the MS-H oppF-1 gene. This mutation was shown to be unique to MS-H in further comparative analyses of oppF-1 genes of MS-H re-isolates and field strains from Australia and other countries. Based on this single nucleotide, a combination of nested PCR and high-resolution melting (HRM) curve analysis was used to evaluate its potential for use in differentiation of MS-H from field strains. The mean genotype confidence percentages of 99.27 and 48.20 for MS-H and field strains, respectively, demonstrated the high discriminative power of the newly developed assay (oppF PCR-HRM). A set of 13 tracheal swab samples collected from MS-H vaccinated specific pathogen free birds and commercial chicken flocks infected with MS were tested using the oppF PCR-HRM test and results were totally consistent with those obtained using vlhA genotyping. The nested-PCR HRM method established in this study proved to be a rapid, simple and cost effective tool for discriminating the MS-H vaccine strain from Australian and international strains in pure cultures and on tracheal swabs. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Theoretical Conversions of Different Hardness and Tensile Strength for Ductile Materials Based on Stress-Strain Curves

    Science.gov (United States)

    Chen, Hui; Cai, Li-Xun

    2018-04-01

    Based on the power-law stress-strain relation and equivalent energy principle, theoretical equations for converting between Brinell hardness (HB), Rockwell hardness (HR), and Vickers hardness (HV) were established. Combining the pre-existing relation between the tensile strength ( σ b ) and Hollomon parameters ( K, N), theoretical conversions between hardness (HB/HR/HV) and tensile strength ( σ b ) were obtained as well. In addition, to confirm the pre-existing σ b -( K, N) relation, a large number of uniaxial tensile tests were conducted in various ductile materials. Finally, to verify the theoretical conversions, plenty of statistical data listed in ASTM and ISO standards were adopted to test the robustness of the converting equations with various hardness and tensile strength. The results show that both hardness conversions and hardness-strength conversions calculated from the theoretical equations accord well with the standard data.

  9. Buckling and free vibration of shallow curved micro/nano-beam based on strain gradient theory under thermal loading with temperature-dependent properties

    Science.gov (United States)

    Rahmani, O.; Hosseini, S. A. H.; Ghoytasi, I.; Golmohammadi, H.

    2017-01-01

    In this study, influences of a uniform thermomechanical loading in buckling and free vibration of a curved FG microbeam have been investigated, based on strain gradient theory (SGT) theory and Timoshenko beam model. Distribution of structural materials varies continuously in thickness direction due to power-law exponent. Unlike classical models, this novel model employs three length scale parameters which can capture the size effect. This work is based on SGT theory and Timoshenko beam model. Governing equation of motion and associated boundary condition have been developed based on Hamilton's principle, which is the specified case of virtual work theorem. In continuance, final differential equations were solved by Navier's solution method and the results have been presented. Moreover, influences of dimensionless length-to-thickness ratio (aspect ratio), dimensionless length scale parameter, power-law exponent, temperature difference and arc angle for various values of mode numbers on natural frequency and critical temperature by considering temperature-dependent material properties have been investigated. In order to validate accomplished study, some of the results were compared with those of previous works. It has been concluded that applying a thermomechanical loading on a FG microbeam causes the natural frequency to become more sensitive about variations of geometrical, physical and mechanical properties and characteristics.

  10. PNNL Stress/Strain Correlation for Zircaloy

    Energy Technology Data Exchange (ETDEWEB)

    Geelhood, Kenneth J.; Beyer, Carl E.; Luscher, Walter G.

    2008-07-18

    Pacific Northwest National Laboratory (PNNL) was tasked with incorporating cladding mechanical property data into the Nuclear Regulatory Commission (NRC) fuel codes, FRAPCON-31 and FRAPTRAN2, by the NRC Office of Nuclear Reactor Research. The objective of that task was to create a mechanical model that can calculate true stress, true strain, and the possible failure of the fuel rod cladding based on uniaxial test data.

  11. The influence of damage on the adiabatic stress-strain curve of aluminium alloy AA7075 under impact-tensile-loading; Der Einfluss von Schaedigung auf die adiabatische Fliesskurve der Aluminiumlegierung AA7075 unter Schlagzugbeanspruchung

    Energy Technology Data Exchange (ETDEWEB)

    El-Magd, E.; Brodmann, M. [Technische Hochschule Aachen (Germany). Lehr- und Forschungsgebiet Werkstoffkunde

    1999-09-01

    The flow behaviour of the aluminium wrought alloy AA7075 is studied in impact tension tests with strain rates between 1000 s{sup -1} and 4000 s{sup -1} on smooth tensile bars. The neck formation is discussed on the basis of the theory of imperfections under consideration of the increased strain rate sensitivity of the material and the adiabatic character of the deformation process at high strain rates. The experimentally determined stress-strain curves show that the flow stress starts to decrease seriously after reaching a strain value between 0.05 and 0.15. This reduction of the flow stress is found to be too high to be explained only by the influence of the adiabatic character of the deformation process. Metallographical investigations show successive damage within the material due to the nucleation of voids and micro-cracks at precipitation particles. Two different heat treatment conditions are investigated in order to determine the influence of particle size, volume fraction and distribution on the damage process. The evolution of damage is found to follow the Avrami-function. Taking the influence of strain rate and damage into consideration a material law is formulated which allows an adequate description of the material behaviour in the range of high strain rates. (orig.)

  12. Triaxial behaviour of a micro-concrete complete stress-strain curves for confining pressures ranging from 0 to 100 MPa

    International Nuclear Information System (INIS)

    Jamet, P.; Millard, A.; Nahas, G.

    1984-05-01

    A series of triaxial tests has been performed on micro-concrete cylinders. The specimens have been strained with a constant displacement rate, up to a deformation of about 10%. Two different domains were distinguihed. For low confining pressures strain softening is observed, the behaviour of the material becomes ductile for high confining pressures. Continuous measurement of the volume of fluid which had to be injected or withdrawn from the cell, to keep the confining pressure constant during the test, allowed to obtain data, concerning the overall lateral deformations of the specimens. Some specimens were also subjected to successive loadings with different confining pressures, in order to study the influence of stress path

  13. Experimental aspects of stress-strain curves determination at high temperature and controlled atmosphere: Al{sub 2}O{sub 3}-MgO-C refractories; Aspectos experimentales de la determinacion de curvas esfuerzo-deformacion a alta temperatura y en atmosfera controlada: Refractarios Al{sub 2}O{sub 3}-MgO-C

    Energy Technology Data Exchange (ETDEWEB)

    Munoz, V.; Rohr, G. A.; Tomba Martinez, A. G.; Cavalieri, A. L.

    2011-07-01

    A methodology for the mechanical evaluation of refractory materials at high temperatures and controlled atmosphere, designed and implemented in the Structural Materials Laboratory of Ceramics Division of INTEMA, is described. The methodology includes the measurement of the specimen deformation by contact extensometry in compression tests to obtain stress-strain curves and the use of a gaseous flow as a system to control atmosphere. The determination of stress-strain curves of Al{sub 2}O{sub 3}-MgO-C commercial refractories used in steelmaking ladles at room temperature and 1260 degree centigrade in different atmospheres is presented as an example of application of this methodology. (Author) 34 refs.

  14. Nonlinear mechanics of rigidifying curves.

    Science.gov (United States)

    Al Mosleh, Salem; Santangelo, Christian

    2017-07-01

    Thin shells are characterized by a high cost of stretching compared to bending. As a result isometries of the midsurface of a shell play a crucial role in their mechanics. In turn, curves on the midsurface with zero normal curvature play a critical role in determining the number and behavior of isometries. In this paper, we show how the presence of these curves results in a decrease in the number of linear isometries. Paradoxically, shells are also known to continuously fold more easily across these rigidifying curves than other curves on the surface. We show how including nonlinearities in the strain can explain these phenomena and demonstrate folding isometries with explicit solutions to the nonlinear isometry equations. In addition to explicit solutions, exact geometric arguments are given to validate and guide our analysis in a coordinate-free way.

  15. Lagrangian Curves on Spectral Curves of Monopoles

    International Nuclear Information System (INIS)

    Guilfoyle, Brendan; Khalid, Madeeha; Ramon Mari, Jose J.

    2010-01-01

    We study Lagrangian points on smooth holomorphic curves in TP 1 equipped with a natural neutral Kaehler structure, and prove that they must form real curves. By virtue of the identification of TP 1 with the space LE 3 of oriented affine lines in Euclidean 3-space, these Lagrangian curves give rise to ruled surfaces in E 3 , which we prove have zero Gauss curvature. Each ruled surface is shown to be the tangent lines to a curve in E 3 , called the edge of regression of the ruled surface. We give an alternative characterization of these curves as the points in E 3 where the number of oriented lines in the complex curve Σ that pass through the point is less than the degree of Σ. We then apply these results to the spectral curves of certain monopoles and construct the ruled surfaces and edges of regression generated by the Lagrangian curves.

  16. Curves from Motion, Motion from Curves

    Science.gov (United States)

    2000-01-01

    tautochrone and brachistochrone properties. To Descartes, however, the rectification of curves such as the spiral (3) and the cycloid (4) was suspect - they...UNCLASSIFIED Defense Technical Information Center Compilation Part Notice ADP012017 TITLE: Curves from Motion, Motion from Curves DISTRIBUTION...Approved for public release, distribution unlimited This paper is part of the following report: TITLE: International Conference on Curves and Surfaces [4th

  17. Multiphasic growth curve analysis.

    NARCIS (Netherlands)

    Koops, W.J.

    1986-01-01

    Application of a multiphasic growth curve is demonstrated with 4 data sets, adopted from literature. The growth curve used is a summation of n logistic growth functions. Human height growth curves of this type are known as "double logistic" (n = 2) and "triple logistic" (n = 3) growth curves (Bock

  18. Contractibility of curves

    Directory of Open Access Journals (Sweden)

    Janusz Charatonik

    1991-11-01

    Full Text Available Results concerning contractibility of curves (equivalently: of dendroids are collected and discussed in the paper. Interrelations tetween various conditions which are either sufficient or necessary for a curve to be contractible are studied.

  19. Space-filling Curves

    Indian Academy of Sciences (India)

    In this article some Peano curves are exhibited and some of their recent applications are dis- cussed. A C++ program to draw the Hilbert curve approximately is given. 1. Introduction. A 'continuous curve' in the plane is usually defined as the path traced by a moving point (x (t), Y (t)) as t runs over an interval of the real line, ...

  20. The Jordan Curve Theorem

    Indian Academy of Sciences (India)

    Institute, Calcutta. Apart from mathematics, he likes painting and reading. Unlike most others he dislikes computers. Ritabrata Munshi. Introduction. In this two-part article we will consider one of the classi- cal theorems of mathematics, the Jordan curve theorem. It states that a simple closed curve (i.e., a closed curve which.

  1. Curved bones: An adaptation to habitual loading.

    Science.gov (United States)

    Milne, Nick

    2016-10-21

    Why are long bones curved? It has long been considered a paradox that many long bones supporting mammalian bodies are curved, since this curvature results in the bone undergoing greater bending, with higher strains and so greater fracture risk under load. This study develops a theoretical model wherein the curvature is a response to bending strains imposed by the requirements of locomotion. In particular the radioulna of obligate quadrupeds is a lever operated by the triceps muscle, and the bending strains induced by the triceps muscle counter the bending resulting from longitudinal loads acting on the curved bone. Indeed the theoretical model reverses this logic and suggests that the curvature is itself a response to the predictable bending strains induced by the triceps muscle. This, in turn, results in anatomical arrangements of bone, muscle and tendon that create a simple physiological mechanism whereby the bone can resist the bending due to the action of triceps in supporting and moving the body. The model is illustrated by contrasting the behaviour of a finite element model of a llama radioulna to that of a straightened version of the same bone. The results show that longitudinal and flexor muscle forces produce bending strains that effectively counter strains due to the pull of the triceps muscle in the curved but not in the straightened model. It is concluded that the curvature of these and other curved bones adds resilience to the skeleton by acting as pre-stressed beams or strainable pre-buckled struts. It is also proposed that the cranial bending strains that result from triceps, acting on the lever that is the radioulna, can explain the development of the curvature of such bones. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

  2. ECM using Edwards curves

    DEFF Research Database (Denmark)

    Bernstein, Daniel J.; Birkner, Peter; Lange, Tanja

    2013-01-01

    This paper introduces EECM-MPFQ, a fast implementation of the elliptic-curve method of factoring integers. EECM-MPFQ uses fewer modular multiplications than the well-known GMP-ECM software, takes less time than GMP-ECM, and finds more primes than GMP-ECM. The main improvements above the modular......-arithmetic level are as follows: (1) use Edwards curves instead of Montgomery curves; (2) use extended Edwards coordinates; (3) use signed-sliding-window addition-subtraction chains; (4) batch primes to increase the window size; (5) choose curves with small parameters and base points; (6) choose curves with large...

  3. Space-filling Curves

    Indian Academy of Sciences (India)

    mathematics and computer applications for the last 20 years. He has been a National Science. Talent awardee of. NCERT in mathematics. GENERAL I ARTICLE. Space-filling Curves. ReMittal. In this article some Peano curves are exhibited and some of their recent applications are dis- cussed. A C++ program to draw the ...

  4. Simulating Supernova Light Curves

    Energy Technology Data Exchange (ETDEWEB)

    Even, Wesley Paul [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dolence, Joshua C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-05

    This report discusses supernova light simulations. A brief review of supernovae, basics of supernova light curves, simulation tools used at LANL, and supernova results are included. Further, it happens that many of the same methods used to generate simulated supernova light curves can also be used to model the emission from fireballs generated by explosions in the earth’s atmosphere.

  5. Tempo curves considered harmful

    NARCIS (Netherlands)

    Desain, P.; Honing, H.

    1993-01-01

    In the literature of musicology, computer music research and the psychology of music, timing or tempo measurements are mostly presented in the form of continuous curves. The notion of these tempo curves is dangerous, despite its widespread use, because it lulls its users into the false impression

  6. Power Curve Measurements REWS

    DEFF Research Database (Denmark)

    Federici, Paolo; Georgieva Yankova, Ginka

    The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to a draft of IEC 61400-12-1 Ed.2.......The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to a draft of IEC 61400-12-1 Ed.2....

  7. GEOMETRIC PROGRESSIONS ON ELLIPTIC CURVES.

    Science.gov (United States)

    Ciss, Abdoul Aziz; Moody, Dustin

    2017-01-01

    In this paper, we look at long geometric progressions on different model of elliptic curves, namely Weierstrass curves, Edwards and twisted Edwards curves, Huff curves and general quartics curves. By a geometric progression on an elliptic curve, we mean the existence of rational points on the curve whose x -coordinate (or y -coordinate) are in geometric progression. We find infinite families of twisted Edwards curves and Huff curves with geometric progressions of length 5, an infinite family of Weierstrass curves with 8 term progressions, as well as infinite families of quartic curves containing 10-term geometric progressions.

  8. On the Quaternionic Focal Curves

    Directory of Open Access Journals (Sweden)

    Nurten (BAYRAK GÜRSES

    2017-06-01

    Full Text Available In this study, a brief summary about quaternions and quaternionic curves are firstly presented. Also, the definition of focal curve is given. The focal curve of a smooth curve consists of the centers of its osculating hypersphere.  By using this definition and the quaternionic osculating hyperspheres of these curves, the quaternionic focal curves in the spaces $\\Q$ and $\\Q_\

  9. Learning Curve? Which One?

    Directory of Open Access Journals (Sweden)

    Paulo Prochno

    2004-07-01

    Full Text Available Learning curves have been studied for a long time. These studies provided strong support to the hypothesis that, as organizations produce more of a product, unit costs of production decrease at a decreasing rate (see Argote, 1999 for a comprehensive review of learning curve studies. But the organizational mechanisms that lead to these results are still underexplored. We know some drivers of learning curves (ADLER; CLARK, 1991; LAPRE et al., 2000, but we still lack a more detailed view of the organizational processes behind those curves. Through an ethnographic study, I bring a comprehensive account of the first year of operations of a new automotive plant, describing what was taking place on in the assembly area during the most relevant shifts of the learning curve. The emphasis is then on how learning occurs in that setting. My analysis suggests that the overall learning curve is in fact the result of an integration process that puts together several individual ongoing learning curves in different areas throughout the organization. In the end, I propose a model to understand the evolution of these learning processes and their supporting organizational mechanisms.

  10. SRHA calibration curve

    Data.gov (United States)

    U.S. Environmental Protection Agency — an UV calibration curve for SRHA quantitation. This dataset is associated with the following publication: Chang, X., and D. Bouchard. Surfactant-Wrapped Multiwalled...

  11. Bond yield curve construction

    Directory of Open Access Journals (Sweden)

    Kožul Nataša

    2014-01-01

    Full Text Available In the broadest sense, yield curve indicates the market's view of the evolution of interest rates over time. However, given that cost of borrowing it closely linked to creditworthiness (ability to repay, different yield curves will apply to different currencies, market sectors, or even individual issuers. As government borrowing is indicative of interest rate levels available to other market players in a particular country, and considering that bond issuance still remains the dominant form of sovereign debt, this paper describes yield curve construction using bonds. The relationship between zero-coupon yield, par yield and yield to maturity is given and their usage in determining curve discount factors is described. Their usage in deriving forward rates and pricing related derivative instruments is also discussed.

  12. The Jordan Curve Theorem

    Indian Academy of Sciences (India)

    We had defined when an arc is said to cross a circle. We broaden the definition of crossing as follows: Definition: Suppose f is a piece-wise circular simple closed curve and, is a piece-wise circular arc. Suppose ..... curve formed by p' pp", q' qq", part of r between p' and q' and part of r between pI! and q", as shown (Figures 6 ...

  13. Power Curve Measurements FGW

    DEFF Research Database (Denmark)

    Georgieva Yankova, Ginka; Federici, Paolo

    This report describes power curve measurements carried out on a given turbine in a chosen period. The measurements are carried out in accordance to IEC 61400-12-1 Ed. 1 and FGW Teil 2.......This report describes power curve measurements carried out on a given turbine in a chosen period. The measurements are carried out in accordance to IEC 61400-12-1 Ed. 1 and FGW Teil 2....

  14. Power Curve Measurements REWS

    DEFF Research Database (Denmark)

    Gómez Arranz, Paula; Vesth, Allan

    This report describes the power curve measurements carried out on a given wind turbine in a chosen period. The measurements were carried out following the measurement procedure in the draft of IEC 61400-12-1 Ed.2 [1], with some deviations mostly regarding uncertainty calculation. Here, the refere......This report describes the power curve measurements carried out on a given wind turbine in a chosen period. The measurements were carried out following the measurement procedure in the draft of IEC 61400-12-1 Ed.2 [1], with some deviations mostly regarding uncertainty calculation. Here......, the reference wind speed used in the power curve is the equivalent wind speed obtained from lidar measurements at several heights between lower and upper blade tip, in combination with a hub height meteorological mast. The measurements have been performed using DTU’s measurement equipment, the analysis...

  15. Algebraic curves and cryptography

    CERN Document Server

    Murty, V Kumar

    2010-01-01

    It is by now a well-known paradigm that public-key cryptosystems can be built using finite Abelian groups and that algebraic geometry provides a supply of such groups through Abelian varieties over finite fields. Of special interest are the Abelian varieties that are Jacobians of algebraic curves. All of the articles in this volume are centered on the theme of point counting and explicit arithmetic on the Jacobians of curves over finite fields. The topics covered include Schoof's \\ell-adic point counting algorithm, the p-adic algorithms of Kedlaya and Denef-Vercauteren, explicit arithmetic on

  16. Complementary curves of descent

    Science.gov (United States)

    Mungan, Carl E.; Lipscombe, Trevor C.

    2013-01-01

    The shapes of two wires in a vertical plane with the same starting and ending points are described as complementary curves of descent if beads frictionlessly slide down both of them in the same time, starting from rest. Every analytic curve has a unique complement, except for a cycloid (solution of the brachistochrone problem), which is self complementary. A striking example is a straight wire whose complement is a lemniscate of Bernoulli. Alternatively, the wires can be tracks down which round objects undergo a rolling race. The level of presentation is appropriate for an intermediate undergraduate course in classical mechanics.

  17. Carbon Lorenz Curves

    NARCIS (Netherlands)

    Groot, L.F.M.|info:eu-repo/dai/nl/073642398

    2008-01-01

    The purpose of this paper is twofold. First, it exhibits that standard tools in the measurement of income inequality, such as the Lorenz curve and the Gini-index, can successfully be applied to the issues of inequality measurement of carbon emissions and the equity of abatement policies across

  18. The Bacterial Growth Curve.

    Science.gov (United States)

    Paulton, Richard J. L.

    1991-01-01

    A procedure that allows students to view an entire bacterial growth curve during a two- to three-hour student laboratory period is described. Observations of the lag phase, logarithmic phase, maximum stationary phase, and phase of decline are possible. A nonpathogenic, marine bacterium is used in the investigation. (KR)

  19. Learning curves for insertion

    African Journals Online (AJOL)

    Adele

    Introduction. Both the Unique™ LMA, and lately the Cobra™ PLA, is available in most of the larger state hospitals in South Africa. This study's objective is to evaluate and compare the learning curves for insertion of these two single-use airway devices. This is to ascertain which of these two devices is easier and safer to ...

  20. Power Curve Measurements

    DEFF Research Database (Denmark)

    Kock, Carsten Weber; Vesth, Allan

    The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...... analyze of power performance of the turbine....

  1. Power Curve Measurements

    DEFF Research Database (Denmark)

    Federici, Paolo; Kock, Carsten Weber

    This report describes the power curve measurements performed with a nacelle LIDAR on a given wind turbine in a wind farm and during a chosen measurement period. The measurements and analysis are carried out in accordance to the guidelines in the procedure “DTU Wind Energy-E-0019” [1]. The reporting...

  2. Power Curve Measurements

    DEFF Research Database (Denmark)

    Gómez Arranz, Paula; Villanueva, Héctor

    The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...... analyze of power performance of the turbine...

  3. Power Curve Measurements, FGW

    DEFF Research Database (Denmark)

    Gómez Arranz, Paula; Kock, Carsten Weber

    The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...... analyze of power performance of the turbine....

  4. Power Curve Measurements

    DEFF Research Database (Denmark)

    Georgieva Yankova, Ginka; Villanueva, Héctor

    The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present anal...

  5. Power Curve Measurements REWS

    DEFF Research Database (Denmark)

    Villanueva, Héctor; Vesth, Allan

    This report describes the power curve measurements carried out on a given wind turbine in a chosen period. The measurements were carried out following the measurement procedure in the draft of IEC 61400-12-1 Ed.2 [1], with some deviations mostly regarding uncertainty calculation. Here, the refere...

  6. Power Curve Measurements FGW

    DEFF Research Database (Denmark)

    Gómez Arranz, Paula; Villanueva, Héctor

    The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present anal...

  7. Textbook Factor Demand Curves.

    Science.gov (United States)

    Davis, Joe C.

    1994-01-01

    Maintains that teachers and textbook graphics follow the same basic pattern in illustrating changes in demand curves when product prices increase. Asserts that the use of computer graphics will enable teachers to be more precise in their graphic presentation of price elasticity. (CFR)

  8. Power curve report

    DEFF Research Database (Denmark)

    Vesth, Allan; Kock, Carsten Weber

    The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...... analyze of power performance of the turbine....

  9. Power Curve Measurements REWS

    DEFF Research Database (Denmark)

    Villanueva, Héctor; Gómez Arranz, Paula

    , the reference wind speed used in the power curve is the equivalent wind speed obtained from lidar measurements at several heights between lower and upper blade tip, in combination with a hub height meteorological mast. The measurements have been performed using DTU’s measurement equipment, the analysis...

  10. Power Curve Measurements, REWS

    DEFF Research Database (Denmark)

    Villanueva, Héctor; Gómez Arranz, Paula

    , the reference wind speed used in the power curve is the equivalent wind speed obtained from lidar measurements at several heights between lower and upper blade tip, in combination with a hub height meteorological mast. The measurements have been performed using DTU’s measurement equipment, the analysis...

  11. Power Curve Measurements FGW

    DEFF Research Database (Denmark)

    Federici, Paolo; Kock, Carsten Weber

    The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...... analyze of power performance of the turbine...

  12. Nacelle lidar power curve

    DEFF Research Database (Denmark)

    Gómez Arranz, Paula; Wagner, Rozenn

    This report describes the power curve measurements performed with a nacelle LIDAR on a given wind turbine in a wind farm and during a chosen measurement period. The measurements and analysis are carried out in accordance to the guidelines in the procedure “DTU Wind Energy-E-0019” [1]. The reporting...

  13. Approximation by planar elastic curves

    DEFF Research Database (Denmark)

    Brander, David; Gravesen, Jens; Nørbjerg, Toke Bjerge

    2016-01-01

    We give an algorithm for approximating a given plane curve segment by a planar elastic curve. The method depends on an analytic representation of the space of elastic curve segments, together with a geometric method for obtaining a good initial guess for the approximating curve. A gradient-driven...

  14. Carbon Lorenz Curves

    Energy Technology Data Exchange (ETDEWEB)

    Groot, L. [Utrecht University, Utrecht School of Economics, Janskerkhof 12, 3512 BL Utrecht (Netherlands)

    2008-11-15

    The purpose of this paper is twofold. First, it exhibits that standard tools in the measurement of income inequality, such as the Lorenz curve and the Gini-index, can successfully be applied to the issues of inequality measurement of carbon emissions and the equity of abatement policies across countries. These tools allow policy-makers and the general public to grasp at a single glance the impact of conventional distribution rules such as equal caps or grandfathering, or more sophisticated ones, on the distribution of greenhouse gas emissions. Second, using the Samuelson rule for the optimal provision of a public good, the Pareto-optimal distribution of carbon emissions is compared with the distribution that follows if countries follow Nash-Cournot abatement strategies. It is shown that the Pareto-optimal distribution under the Samuelson rule can be approximated by the equal cap division, represented by the diagonal in the Lorenz curve diagram.

  15. Power curve investigation

    DEFF Research Database (Denmark)

    Villanueva, Héctor; Gómez Arranz, Paula

    This report describes the analysis carried out with data from a given turbine in a wind farm and a chosen period. The purpose of the analysis is to correlate the power output of the wind turbine to the wind speed measured by a nacelle-mounted anemometer. The measurements and analysis are not perf......This report describes the analysis carried out with data from a given turbine in a wind farm and a chosen period. The purpose of the analysis is to correlate the power output of the wind turbine to the wind speed measured by a nacelle-mounted anemometer. The measurements and analysis...... are not performed according to IEC 61400-12-1 [1]. Therefore, the results presented in this report cannot be considered a power curve according to the reference standard, and are referred to as “power curve investigation” instead. The measurements have been performed by a customer and the data analysis has been...

  16. Managing curved canals

    Directory of Open Access Journals (Sweden)

    Iram Ansari

    2012-01-01

    Full Text Available Dilaceration is the result of a developmental anomaly in which there has been an abrupt change in the axial inclination between the crown and the root of a tooth. Dilaceration can be seen in both the permanent and deciduous dentitions, and is more commonly found in posterior teeth and in maxilla. Periapical radiographs are the most appropriate way to diagnose the presence of root dilacerations. The controlled regularly tapered preparation of the curved canals is the ultimate challenge in endodontics. Careful and meticulous technique will yield a safe and sufficient enlargement of the curved canals. This article gives a review of the literature and three interesting case reports of root dilacerations.

  17. Twists of Elliptic Curves

    Science.gov (United States)

    Kronberg, Max; Soomro, Muhammad Afzal; Top, Jaap

    2017-10-01

    In this note we extend the theory of twists of elliptic curves as presented in various standard texts for characteristic not equal to two or three to the remaining characteristics. For this, we make explicit use of the correspondence between the twists and the Galois cohomology set H^1\\big({G}_{\\overline{K}/K}, \\operatorname{Aut}_{\\overline{K}}(E)\\big). The results are illustrated by examples.

  18. Transvaginal cholecystectomy learning curve.

    Science.gov (United States)

    Wood, Stephanie G; Dai, Feng; Dabu-Bondoc, Susan; Mikhael, Hosni; Vadivelu, Nalini; Duffy, Andrew; Roberts, Kurt E

    2015-07-01

    There are few surgeons in the United States, within private practice and academic centers, currently performing transvaginal cholecystectomies (TVC). The lack of exposure to TVC during residency or fellowship training, coupled with a poorly defined learning curve, further limits interested surgeons who want to apply this technique to their practice. This study describes the learning curve encountered during the introduction of TVC to our academic facility. This study is an analysis of consecutive TVCs performed between August 14, 2009 and August 3, 2012 at an academic center. The TVC patients were divided into sequential quartiles (n = 15/16). The learning curve outcome was measured as the operative time of TVC patients and compared to the operative time of female laparoscopic cholecystectomy (LC) patients performed during the same time period. Sixty-one patients underwent a TVC with a mean age of 38 ± 12 years and mean BMI was 29 ± 6 kg/m(2). Sixty-seven female patients who underwent a LC with average age 41 ± 15 years and average BMI 33 ± 12 kg/m(2). The average operative time of LC patients and TVC patients was 48 ± 20 and 60 ± 17 min, respectively. Significant improvement in TVC operative times was seen between the first (n = 15 TVCs) and second quartiles (p = 0.04) and stayed relatively constant for third quartile, during which there was no statistically significant difference between the mean LC operative time for the second and third TVC quartiles The learning curve of a fellowship-trained surgeon introducing TVC to their surgical repertoire, as measured by improved operative times, can be achieved with approximately 15 cases.

  19. Dynamics of curved fronts

    CERN Document Server

    Pelce, Pierre

    1989-01-01

    In recent years, much progress has been made in the understanding of interface dynamics of various systems: hydrodynamics, crystal growth, chemical reactions, and combustion. Dynamics of Curved Fronts is an important contribution to this field and will be an indispensable reference work for researchers and graduate students in physics, applied mathematics, and chemical engineering. The book consist of a 100 page introduction by the editor and 33 seminal articles from various disciplines.

  20. LCC: Light Curves Classifier

    Science.gov (United States)

    Vo, Martin

    2017-08-01

    Light Curves Classifier uses data mining and machine learning to obtain and classify desired objects. This task can be accomplished by attributes of light curves or any time series, including shapes, histograms, or variograms, or by other available information about the inspected objects, such as color indices, temperatures, and abundances. After specifying features which describe the objects to be searched, the software trains on a given training sample, and can then be used for unsupervised clustering for visualizing the natural separation of the sample. The package can be also used for automatic tuning parameters of used methods (for example, number of hidden neurons or binning ratio). Trained classifiers can be used for filtering outputs from astronomical databases or data stored locally. The Light Curve Classifier can also be used for simple downloading of light curves and all available information of queried stars. It natively can connect to OgleII, OgleIII, ASAS, CoRoT, Kepler, Catalina and MACHO, and new connectors or descriptors can be implemented. In addition to direct usage of the package and command line UI, the program can be used through a web interface. Users can create jobs for ”training” methods on given objects, querying databases and filtering outputs by trained filters. Preimplemented descriptors, classifier and connectors can be picked by simple clicks and their parameters can be tuned by giving ranges of these values. All combinations are then calculated and the best one is used for creating the filter. Natural separation of the data can be visualized by unsupervised clustering.

  1. Wolff: straight not curved.

    Science.gov (United States)

    Hammer, A

    2017-11-01

    It was 140 years ago that George von Meyer presented his anatomical diagrams of human bones to a meeting in Zurich. There he was told by Prof. Karl Culmann that the trabecular lines shown within the diagram of the upper femur closely resembled those lines of force which Culmann had determined with Graphic Statics to be passing through a curved, loaded Fairbairn crane. This drew the attention of Julius Wolff, who used this as the basis for his 'Trajectorial theory' which was widely accepted and, to date, has been the underlying basis for all biomechanical investigations of this region. Following Wolff and Culmann, the upper femur is considered to be a curved structure and is investigated as such. Unfortunately, this concept is wrong. The upper femur is not curved but is angular. It is formed by the junction of two straight bones, the femoral neck and the femoral shaft, as may be simply seen as the neck/shaft angle constructed on the antero-posterior radiograph of any normal femur. The internal trabecular bone forms only part of the load bearing structure of the femoral neck. The configuration of this trabecular substance in this region suggests that it is related specifically to the force present during flexion and extension movements of the hip joint. This being so, combined with the delayed timing of the appearance of the trabecular columns, it must be questioned as to whether the remodelling of the upper femur is in response to one or to two distinct forces.

  2. Determination of Tensile Properties of Polymers at High Strain Rates

    Directory of Open Access Journals (Sweden)

    Major Z.

    2010-06-01

    Full Text Available In the field of high rate testing of polymers the measured properties are highly dependent on the applied methodology. Hence, the test setup as whole but in particular also the geometrical type of specimen plays a decisive role. The widely used standard for the determination of tensile properties of polymers (ISO527-2 was extended by a novel standard (ISO18872:2007, which is targeted on the determination of tensile properties at high strain rates. In this standard also a novel specimen shape is proposed. Hand in hand with the introduction of new specimen geometry the question of comparability arises. To point out the differences in stress-strain response of the ISO18872 specimen and the ISO527-2 multipurpose specimen tensile tests over a wide loading rate range were conducted in this paper. A digital image correlation system in combination with a high speed camera was used to characterize the local material behaviour. Different parameters like nominal stress, true stress, nominal strain, true strain as well as volumetric strain were determined and used to compare the two specimen geometries.

  3. Minimal genus one curves

    OpenAIRE

    Sadek, Mohammad

    2012-01-01

    In this paper we consider genus one equations of degree $n$, namely a (generalised) binary quartic when $n=2$, a ternary cubic when $n=3$, and a pair of quaternary quadrics when $n=4$. A new definition for the minimality of genus one equations of degree $n$ over local fields is introduced. The advantage of this definition is that it does not depend on invariant theory of genus one curves. We prove that this definition coincides with the classical definition of minimality for all $n\\le4$. As a...

  4. Learning from uncertain curves

    DEFF Research Database (Denmark)

    Mallasto, Anton; Feragen, Aasa

    2017-01-01

    We introduce a novel framework for statistical analysis of populations of nondegenerate Gaussian processes (GPs), which are natural representations of uncertain curves. This allows inherent variation or uncertainty in function-valued data to be properly incorporated in the population analysis....... Using the 2-Wasserstein metric we geometrize the space of GPs with L2 mean and covariance functions over compact index spaces. We prove uniqueness of the barycenter of a population of GPs, as well as convergence of the metric and the barycenter of their finite-dimensional counterparts. This justifies...

  5. The Characteristic Curves of Water

    Science.gov (United States)

    Neumaier, Arnold; Deiters, Ulrich K.

    2016-09-01

    In 1960, E. H. Brown defined a set of characteristic curves (also known as ideal curves) of pure fluids, along which some thermodynamic properties match those of an ideal gas. These curves are used for testing the extrapolation behaviour of equations of state. This work is revisited, and an elegant representation of the first-order characteristic curves as level curves of a master function is proposed. It is shown that Brown's postulate—that these curves are unique and dome-shaped in a double-logarithmic p, T representation—may fail for fluids exhibiting a density anomaly. A careful study of the Amagat curve (Joule inversion curve) generated from the IAPWS-95 reference equation of state for water reveals the existence of an additional branch.

  6. Curved-Duct

    Directory of Open Access Journals (Sweden)

    Je Hyun Baekt

    2000-01-01

    Full Text Available A numerical study is conducted on the fully-developed laminar flow of an incompressible viscous fluid in a square duct rotating about a perpendicular axis to the axial direction of the duct. At the straight duct, the rotation produces vortices due to the Coriolis force. Generally two vortex cells are formed and the axial velocity distribution is distorted by the effect of this Coriolis force. When a convective force is weak, two counter-rotating vortices are shown with a quasi-parabolic axial velocity profile for weak rotation rates. As the rotation rate increases, the axial velocity on the vertical centreline of the duct begins to flatten and the location of vorticity center is moved near to wall by the effect of the Coriolis force. When the convective inertia force is strong, a double-vortex secondary flow appears in the transverse planes of the duct for weak rotation rates but as the speed of rotation increases the secondary flow is shown to split into an asymmetric configuration of four counter-rotating vortices. If the rotation rates are increased further, the secondary flow restabilizes to a slightly asymmetric double-vortex configuration. Also, a numerical study is conducted on the laminar flow of an incompressible viscous fluid in a 90°-bend square duct that rotates about axis parallel to the axial direction of the inlet. At a 90°-bend square duct, the feature of flow by the effect of a Coriolis force and a centrifugal force, namely a secondary flow by the centrifugal force in the curved region and the Coriolis force in the downstream region, is shown since the centrifugal force in curved region and the Coriolis force in downstream region are dominant respectively.

  7. Magnetism in curved geometries

    Science.gov (United States)

    Streubel, Robert

    Deterministically bending and twisting two-dimensional structures in the three-dimensional (3D) space provide means to modify conventional or to launch novel functionalities by tailoring curvature and 3D shape. The recent developments of 3D curved magnetic geometries, ranging from theoretical predictions over fabrication to characterization using integral means as well as advanced magnetic tomography, will be reviewed. Theoretical works predict a curvature-induced effective anisotropy and effective Dzyaloshinskii-Moriya interaction resulting in a vast of novel effects including magnetochiral effects (chirality symmetry breaking) and topologically induced magnetization patterning. The remarkable development of nanotechnology, e.g. preparation of high-quality extended thin films, nanowires and frameworks via chemical and physical deposition as well as 3D nano printing, has granted first insights into the fundamental properties of 3D shaped magnetic objects. Optimizing magnetic and structural properties of these novel 3D architectures demands new investigation methods, particularly those based on vector tomographic imaging. Magnetic neutron tomography and electron-based 3D imaging, such as electron holography and vector field electron tomography, are well-established techniques to investigate macroscopic and nanoscopic samples, respectively. At the mesoscale, the curved objects can be investigated using the novel method of magnetic X-ray tomography. In spite of experimental challenges to address the appealing theoretical predictions of curvature-induced effects, those 3D magnetic architectures have already proven their application potential for life sciences, targeted delivery, realization of 3D spin-wave filters, and magneto-encephalography devices, to name just a few. DOE BES MSED (DE-AC02-05-CH11231).

  8. Titration Curves: Fact and Fiction.

    Science.gov (United States)

    Chamberlain, John

    1997-01-01

    Discusses ways in which datalogging equipment can enable titration curves to be measured accurately and how computing power can be used to predict the shape of curves. Highlights include sources of error, use of spreadsheets to generate titration curves, titration of a weak acid with a strong alkali, dibasic acids, weak acid and weak base, and…

  9. A Journey Between Two Curves

    Directory of Open Access Journals (Sweden)

    Sergey A. Cherkis

    2007-03-01

    Full Text Available A typical solution of an integrable system is described in terms of a holomorphic curve and a line bundle over it. The curve provides the action variables while the time evolution is a linear flow on the curve's Jacobian. Even though the system of Nahm equations is closely related to the Hitchin system, the curves appearing in these two cases have very different nature. The former can be described in terms of some classical scattering problem while the latter provides a solution to some Seiberg-Witten gauge theory. This note identifies the setup in which one can formulate the question of relating the two curves.

  10. Membrane Buckling Induced by Curved Filaments

    Science.gov (United States)

    Lenz, Martin; Crow, Daniel J. G.; Joanny, Jean-François

    2009-07-01

    We present a novel buckling instability relevant to membrane budding in eukaryotic cells. In this mechanism, curved filaments bind to a lipid bilayer without changing its intrinsic curvature. As more and more filaments adsorb, newly added ones are more and more strained, which destabilizes the flat membrane. We perform a linear stability analysis of filament-dressed membranes and find that the buckling threshold is within reasonable in vivo parameter values. We account for the formation of long tubes previously observed in cells and in purified systems. We study strongly deformed dressed membranes and their bifurcation diagram numerically. Our mechanism could be validated by a simple experiment.

  11. Soil Water Retention Curve

    Science.gov (United States)

    Johnson, L. E.; Kim, J.; Cifelli, R.; Chandra, C. V.

    2016-12-01

    Potential water retention, S, is one of parameters commonly used in hydrologic modeling for soil moisture accounting. Physically, S indicates total amount of water which can be stored in soil and is expressed in units of depth. S can be represented as a change of soil moisture content and in this context is commonly used to estimate direct runoff, especially in the Soil Conservation Service (SCS) curve number (CN) method. Generally, the lumped and the distributed hydrologic models can easily use the SCS-CN method to estimate direct runoff. Changes in potential water retention have been used in previous SCS-CN studies; however, these studies have focused on long-term hydrologic simulations where S is allowed to vary at the daily time scale. While useful for hydrologic events that span multiple days, the resolution is too coarse for short-term applications such as flash flood events where S may not recover its full potential. In this study, a new method for estimating a time-variable potential water retention at hourly time-scales is presented. The methodology is applied for the Napa River basin, California. The streamflow gage at St Helena, located in the upper reaches of the basin, is used as the control gage site to evaluate the model performance as it is has minimal influences by reservoirs and diversions. Rainfall events from 2011 to 2012 are used for estimating the event-based SCS CN to transfer to S. As a result, we have derived the potential water retention curve and it is classified into three sections depending on the relative change in S. The first is a negative slope section arising from the difference in the rate of moving water through the soil column, the second is a zero change section representing the initial recovery the potential water retention, and the third is a positive change section representing the full recovery of the potential water retention. Also, we found that the soil water moving has traffic jam within 24 hours after finished first

  12. Geometric nonlinear dynamic analysis of curved beams using curved beam element

    Science.gov (United States)

    Pan, Ke-Qi; Liu, Jin-Yang

    2011-12-01

    Instead of using the previous straight beam element to approximate the curved beam, in this paper, a curvilinear coordinate is employed to describe the deformations, and a new curved beam element is proposed to model the curved beam. Based on exact nonlinear strain-displacement relation, virtual work principle is used to derive dynamic equations for a rotating curved beam, with the effects of axial extensibility, shear deformation and rotary inertia taken into account. The constant matrices are solved numerically utilizing the Gauss quadrature integration method. Newmark and Newton-Raphson iteration methods are adopted to solve the differential equations of the rigid-flexible coupling system. The present results are compared with those obtained by commercial programs to validate the present finite method. In order to further illustrate the convergence and efficiency characteristics of the present modeling and computation formulation, comparison of the results of the present formulation with those of the ADAMS software are made. Furthermore, the present results obtained from linear formulation are compared with those from nonlinear formulation, and the special dynamic characteristics of the curved beam are concluded by comparison with those of the straight beam.

  13. Intersection numbers of spectral curves

    CERN Document Server

    Eynard, B

    2011-01-01

    We compute the symplectic invariants of an arbitrary spectral curve with only 1 branchpoint in terms of integrals of characteristic classes in the moduli space of curves. Our formula associates to any spectral curve, a characteristic class, which is determined by the laplace transform of the spectral curve. This is a hint to the key role of Laplace transform in mirror symmetry. When the spectral curve is y=\\sqrt{x}, the formula gives Kontsevich--Witten intersection numbers, when the spectral curve is chosen to be the Lambert function \\exp{x}=y\\exp{-y}, the formula gives the ELSV formula for Hurwitz numbers, and when one chooses the mirror of C^3 with framing f, i.e. \\exp{-x}=\\exp{-yf}(1-\\exp{-y}), the formula gives the topological vertex formula, i.e. the generating function of Gromov-Witten invariants of C^3. In some sense this formula generalizes ELSV formula, and Mumford formula.

  14. Optimization on Spaces of Curves

    DEFF Research Database (Denmark)

    Møller-Andersen, Jakob

    This thesis is concerned with computational and theoretical aspects of Riemannian metrics on spaces of regular curves, and their applications. It was recently proved that second order constant coefficient Sobolev metrics on curves are geodesically complete. We extend this result to the case...... of Sobolev metrics with coefficient functions depending on the length of the curve. We show how to apply this result to analyse a wide range of metrics on the submanifold of unit and constant speed curves. We present a numerical discretization of second order Sobolev metrics on the space of regular curves...... of cardiac deformations. Finally we investigate a new application of Riemannian shape analysis in shape optimization. We setup a simple elliptic model problem, and describe how to apply shape calculus to obtain directional derivatives in the manifold of planar curves. We present an implementation based...

  15. Reflection of curved shock waves

    Science.gov (United States)

    Mölder, S.

    2017-09-01

    Shock curvatures are related to pressure gradients, streamline curvatures and vorticity in flows with planar and axial symmetry. Explicit expressions, in an influence coefficient format, are used to relate post-shock pressure gradient, streamline curvature and vorticity to pre-shock gradients and shock curvature in steady flow. Using higher order, von Neumann-type, compatibility conditions, curved shock theory is applied to calculate the flow near singly and doubly curved shocks on curved surfaces, in regular shock reflection and in Mach reflection. Theoretical curved shock shapes are in good agreement with computational fluid dynamics calculations and experiment.

  16. The comparison of cyclic deformation curve determination for ADI

    Czech Academy of Sciences Publication Activity Database

    Zapletal, J.; Obrtlík, Karel; Věchet, S.

    308 2005, - (2005), s. 305-309 ISSN 1429-6055. [Miedzynarodowe sympozjum /20./. Ustroň-Jaszowiec, 07.12.2005-09.12.2005] R&D Projects: GA ČR(CZ) GA106/03/1265 Institutional research plan: CEZ:AV0Z20410507 Keywords : cyclic stress-strain curve * austempered ductile iron Subject RIV: JG - Metallurgy

  17. Regular homotopy of Hurwitz curves

    International Nuclear Information System (INIS)

    Auroux, D; Kulikov, Vik S; Shevchishin, V V

    2004-01-01

    We prove that any two irreducible cuspidal Hurwitz curves C 0 adn C 1 (or, more generally, two curves with A-type singularities) in the Hirzebruch surface F N with the same homology classes and sets of singularities are regular homotopic. Moreover, they are symplectically regular homotopic if C 0 and C 1 are symplectic with respect to a compatible symplectic form

  18. Space curves, anholonomy and nonlinearity

    Indian Academy of Sciences (India)

    Walker parallel transport [14] of any vector P moved ... of Fermi–Walker parallel transport to the case of a moving space curve. 4. General curve evolution equations .... ear term of the Lamb equation (eq. (34)) is just the time derivative of the total.

  19. Computational aspects of algebraic curves

    CERN Document Server

    Shaska, Tanush

    2005-01-01

    The development of new computational techniques and better computing power has made it possible to attack some classical problems of algebraic geometry. The main goal of this book is to highlight such computational techniques related to algebraic curves. The area of research in algebraic curves is receiving more interest not only from the mathematics community, but also from engineers and computer scientists, because of the importance of algebraic curves in applications including cryptography, coding theory, error-correcting codes, digital imaging, computer vision, and many more.This book cove

  20. CYCLING CURVES AND THEIR APPLICATIONS

    Directory of Open Access Journals (Sweden)

    RAICU Lucian

    2015-06-01

    Full Text Available This paper proposes an analysis of the cyclic curves that can be considered as some of the most important regarding their applications in science, technique, design, architecture and art. These curves include the following: cycloid, epicycloid, hypocycloid, spherical cycloid and special cases thereof. In the first part of the paper the main curves of cycloids family are presented with their methods of generating and setting parametric equations. In the last part some of cycloid applications are highlighted in different areas of science, technology and art.

  1. Elliptic Curves and Number Theory

    Indian Academy of Sciences (India)

    R. Sujatha, School of Mathematics, Tata Institute of Fundamental Research, Mumbai, INDIA

    1. Aim: To explain the connection between a simple ancient problem in number theory and a deep sophisticated conjecture about Elliptic Curves. ('arithmetic Geometry'). Notation: N : set of natural numbers (1,2,3,...) ...

  2. 51Cr - erythrocyte survival curves

    International Nuclear Information System (INIS)

    Paiva Costa, J. de.

    1982-07-01

    Sixteen patients were studied, being fifteen patients in hemolytic state, and a normal individual as a witness. The aim was to obtain better techniques for the analysis of the erythrocytes, survival curves, according to the recommendations of the International Committee of Hematology. It was used the radiochromatic method as a tracer. Previously a revisional study of the International Literature was made in its aspects inherent to the work in execution, rendering possible to establish comparisons and clarify phonomena observed in cur investigation. Several parameters were considered in this study, hindering both the exponential and the linear curves. The analysis of the survival curves of the erythrocytes in the studied group, revealed that the elution factor did not present a homogeneous answer quantitatively to all, though, the result of the analysis of these curves have been established, through listed programs in the electronic calculator. (Author) [pt

  3. Management of the learning curve

    DEFF Research Database (Denmark)

    Pedersen, Peter-Christian; Slepniov, Dmitrij

    2016-01-01

    Purpose – This paper focuses on the management of the learning curve in overseas capacity expansions. The purpose of this paper is to unravel the direct as well as indirect influences on the learning curve and to advance the understanding of how these affect its management. Design/methodology...... the dimensions of the learning process involved in a capacity expansion project and identified the direct and indirect labour influences on the production learning curve. On this basis, the study proposes solutions to managing learning curves in overseas capacity expansions. Furthermore, the paper concludes...... employs qualitative methodology and draws on a longitudinal, factory-level analysis of an in-depth case study of a Danish wind turbine manufacturer. Findings – This study goes beyond a simplistic treatment of the lead time and learning required to establish a new capacity. The authors examined...

  4. Numerical simulation of tensile behaviour of nuclear fuel cladding materials

    International Nuclear Information System (INIS)

    Hosbons, R.R.; Coleman, C.E.; Holt, R.A.

    1975-10-01

    We have developed an expression to describe the true-stress true-strain behaviour of irradiated Zircaloy, the usual fuel sheathing material. The expression includes strain rate sensitivity, work hardening, irradiation hardening and strain softening due to the annihilation of irradiation damage. A cylindrical specimen, containing a slight taper, was used to simulate the development of plastic instability. By combining the phenomenological expression with the model specimen, numerical calculation of tensile tests on irradiated Zircaloy accurately described load-elongation curves, true-stress true-strain behaviour during necking, the effect of irradiation on ductility, and stress relaxation. (author)

  5. Prediction of tensile curves, at 673 K, of cold-worked and stress-relieved zircaloy-4 from creep data

    International Nuclear Information System (INIS)

    Povolo, F.; Buenos Aires Univ. Nacional; Marzocca, A.J.

    1986-01-01

    A constitutive creep equation, based on jog-drag cell-formation, is used to predict tensile curves from creep data obtained in the same material. The predicted tensile curve are compared with actual stress versus plastic strain data, obtained both in cold-work and stress-relieved specimens. Finally, it is shown that the general features of the tensile curves, at low strain rates, are described by the creep model. (orig.)

  6. Dissolution glow curve in LLD

    International Nuclear Information System (INIS)

    Haverkamp, U.; Wiezorek, C.; Poetter, R.

    1990-01-01

    Lyoluminescence dosimetry is based upon light emission during dissolution of previously irradiated dosimetric materials. The lyoluminescence signal is expressed in the dissolution glow curve. These curves begin, depending on the dissolution system, with a high peak followed by an exponentially decreasing intensity. System parameters that influence the graph of the dissolution glow curve, are, for example, injection speed, temperature and pH value of the solution and the design of the dissolution cell. The initial peak does not significantly correlate with the absorbed dose, it is mainly an effect of the injection. The decay of the curve consists of two exponential components: one fast and one slow. The components depend on the absorbed dose and the dosimetric materials used. In particular, the slow component correlates with the absorbed dose. In contrast to the fast component the argument of the exponential function of the slow component is independent of the dosimetric materials investigated: trehalose, glucose and mannitol. The maximum value, following the peak of the curve, and the integral light output are a measure of the absorbed dose. The reason for the different light outputs of various dosimetric materials after irradiation with the same dose is the differing solubility. The character of the dissolution glow curves is the same following irradiation with photons, electrons or neutrons. (author)

  7. Considerations for reference pump curves

    International Nuclear Information System (INIS)

    Stockton, N.B.

    1992-01-01

    This paper examines problems associated with inservice testing (IST) of pumps to assess their hydraulic performance using reference pump curves to establish acceptance criteria. Safety-related pumps at nuclear power plants are tested under the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (the Code), Section 11. The Code requires testing pumps at specific reference points of differential pressure or flow rate that can be readily duplicated during subsequent tests. There are many cases where test conditions cannot be duplicated. For some pumps, such as service water or component cooling pumps, the flow rate at any time depends on plant conditions and the arrangement of multiple independent and constantly changing loads. System conditions cannot be controlled to duplicate a specific reference value. In these cases, utilities frequently request to use pump curves for comparison of test data for acceptance. There is no prescribed method for developing a pump reference curve. The methods vary and may yield substantially different results. Some results are conservative when compared to the Code requirements; some are not. The errors associated with different curve testing techniques should be understood and controlled within reasonable bounds. Manufacturer's pump curves, in general, are not sufficiently accurate to use as reference pump curves for IST. Testing using reference curves generated with polynomial least squares fits over limited ranges of pump operation, cubic spline interpolation, or cubic spline least squares fits can provide a measure of pump hydraulic performance that is at least as accurate as the Code required method. Regardless of the test method, error can be reduced by using more accurate instruments, by correcting for systematic errors, by increasing the number of data points, and by taking repetitive measurements at each data point

  8. Curve Digitizer – A software for multiple curves digitizing

    Directory of Open Access Journals (Sweden)

    Florentin ŞPERLEA

    2010-06-01

    Full Text Available The Curve Digitizer is software that extracts data from an image file representing a graphicand returns them as pairs of numbers which can then be used for further analysis and applications.Numbers can be read on a computer screen stored in files or copied on paper. The final result is adata set that can be used with other tools such as MSEXCEL. Curve Digitizer provides a useful toolfor any researcher or engineer interested in quantifying the data displayed graphically. The image filecan be obtained by scanning a document

  9. Curvature reduces bending strains in the quokka femur

    Directory of Open Access Journals (Sweden)

    Kyle McCabe

    2017-03-01

    Full Text Available This study explores how curvature in the quokka femur may help to reduce bending strain during locomotion. The quokka is a small wallaby, but the curvature of the femur and the muscles active during stance phase are similar to most quadrupedal mammals. Our hypothesis is that the action of hip extensor and ankle plantarflexor muscles during stance phase place cranial bending strains that act to reduce the caudal curvature of the femur. Knee extensors and biarticular muscles that span the femur longitudinally create caudal bending strains in the caudally curved (concave caudal side bone. These opposing strains can balance each other and result in less strain on the bone. We test this idea by comparing the performance of a normally curved finite element model of the quokka femur to a digitally straightened version of the same bone. The normally curved model is indeed less strained than the straightened version. To further examine the relationship between curvature and the strains in the femoral models, we also tested an extra-curved and a reverse-curved version with the same loads. There appears to be a linear relationship between the curvature and the strains experienced by the models. These results demonstrate that longitudinal curvature in bones may be a manipulable mechanism whereby bone can induce a strain gradient to oppose strains induced by habitual loading.

  10. An investigation on vulnerability assessment of steel structures with thin steel shear wall through development of fragility curves

    OpenAIRE

    Mohsen Gerami; Saeed Ghaffari; Amir Mahdi Heidari Tafreshi

    2017-01-01

    Fragility curves play an important role in damage assessment of buildings. Probability of damage induction to the structure against seismic events can be investigated upon generation of afore mentioned curves. In current research 360 time history analyses have been carried out on structures of 3, 10 and 20 story height and subsequently fragility curves have been adopted. The curves are developed based on two indices of inter story drifts and equivalent strip axial strains of the shear wall. T...

  11. Calibration curves for biological dosimetry

    International Nuclear Information System (INIS)

    Guerrero C, C.; Brena V, M. . E-mail cgc@nuclear.inin.mx

    2004-01-01

    The generated information by the investigations in different laboratories of the world, included the ININ, in which settles down that certain class of chromosomal leisure it increases in function of the dose and radiation type, has given by result the obtaining of calibrated curves that are applied in the well-known technique as biological dosimetry. In this work is presented a summary of the work made in the laboratory that includes the calibrated curves for gamma radiation of 60 Cobalt and X rays of 250 k Vp, examples of presumed exposure to ionizing radiation, resolved by means of aberration analysis and the corresponding dose estimate through the equations of the respective curves and finally a comparison among the dose calculations in those people affected by the accident of Ciudad Juarez, carried out by the group of Oak Ridge, USA and those obtained in this laboratory. (Author)

  12. Laffer Curves and Home Production

    Directory of Open Access Journals (Sweden)

    Kotamäki Mauri

    2017-06-01

    Full Text Available In the earlier related literature, consumption tax rate Laffer curve is found to be strictly increasing (see Trabandt and Uhlig (2011. In this paper, a general equilibrium macro model is augmented by introducing a substitute for private consumption in the form of home production. The introduction of home production brings about an additional margin of adjustment – an increase in consumption tax rate not only decreases labor supply and reduces the consumption tax base but also allows a substitution of market goods with home-produced goods. The main objective of this paper is to show that, after the introduction of home production, the consumption tax Laffer curve exhibits an inverse U-shape. Also the income tax Laffer curves are significantly altered. The result shown in this paper casts doubt on some of the earlier results in the literature.

  13. Rational points on elliptic curves

    CERN Document Server

    Silverman, Joseph H

    2015-01-01

    The theory of elliptic curves involves a pleasing blend of algebra, geometry, analysis, and number theory. This book stresses this interplay as it develops the basic theory, thereby providing an opportunity for advanced undergraduates to appreciate the unity of modern mathematics. At the same time, every effort has been made to use only methods and results commonly included in the undergraduate curriculum. This accessibility, the informal writing style, and a wealth of exercises make Rational Points on Elliptic Curves an ideal introduction for students at all levels who are interested in learning about Diophantine equations and arithmetic geometry. Most concretely, an elliptic curve is the set of zeroes of a cubic polynomial in two variables. If the polynomial has rational coefficients, then one can ask for a description of those zeroes whose coordinates are either integers or rational numbers. It is this number theoretic question that is the main subject of this book. Topics covered include the geometry and ...

  14. The New Keynesian Phillips Curve

    DEFF Research Database (Denmark)

    Ólafsson, Tjörvi

    This paper provides a survey on the recent literature on the new Keynesian Phillips curve: the controversies surrounding its microfoundation and estimation, the approaches that have been tried to improve its empirical fit and the challenges it faces adapting to the open-economy framework. The new...... Keynesian Phillips curve has been severely criticized for poor empirical dynamics. Suggested improvements involve making some adjustments to the standard sticky price framework, e.g. introducing backwardness and real rigidities, or abandoning the sticky price model and relying on models of inattentiveness......, learning or state-dependant pricing. The introduction of openeconomy factors into the new Keynesian Phillips curve complicate matters further as it must capture the nexus between price setting, inflation and the exchange rate. This is nevertheless a crucial feature for any model to be used for inflation...

  15. Electro-Mechanical Resonance Curves

    Science.gov (United States)

    Greenslade, Thomas B.

    2018-03-01

    Recently I have been investigating the frequency response of galvanometers. These are direct-current devices used to measure small currents. By using a low-frequency function generator to supply the alternating-current signal and a stopwatch smartphone app to measure the period, I was able to take data to allow a resonance curve to be drawn. This is the sort of project that should provide a fascinating research experience for the introductory physics student. In this article I will discuss the galvanometers that I used in this work, and will show a resonance curve for one of them.

  16. Migration and the Wage Curve:

    DEFF Research Database (Denmark)

    Brücker, Herbert; Jahn, Elke J.

      Based on a wage curve approach we examine the labor market effects of migration in Germany. The wage curve relies on the assumption that wages respond to a change in the unemployment rate, albeit imperfectly. This allows one to derive the wage and employment effects of migration simultaneously...... with a vocational degree. The wage and employment effects of migration are moderate: a 1 percent increase in the German labor force through immigration increases the aggregate unemployment rate by less than 0.1 percentage points and reduces average wages by less 0.1 percent. While native workers benefit from...... increased wages and lower unemployment, foreign workers are adversely affected....

  17. Shock detachment from curved wedges

    Science.gov (United States)

    Mölder, S.

    2017-09-01

    Curved shock theory is used to show that the flow behind attached shocks on doubly curved wedges can have either positive or negative post-shock pressure gradients depending on the freestream Mach number, the wedge angle and the two wedge curvatures. Given enough wedge length, the flow near the leading edge can choke to force the shock to detach from the wedge. This local choking can preempt both the maximum deflection and the sonic criteria for shock detachment. Analytical predictions for detachment by local choking are supported by CFD results.

  18. Dual Smarandache Curves of a Timelike Curve lying on Unit dual Lorentzian Sphere

    OpenAIRE

    Kahraman, Tanju; Hüseyin Ugurlu, Hasan

    2016-01-01

    In this paper, we give Darboux approximation for dual Smarandache curves of time like curve on unit dual Lorentzian sphere. Firstly, we define the four types of dual Smarandache curves of a timelike curve lying on dual Lorentzian sphere.

  19. Archaeomagnetic SV curve for Belgium

    Science.gov (United States)

    Ech-chakrouni, Souad; Hus, Jozef

    2017-04-01

    Archaeomagnetic secular variation curves have been established for different countries in Europe, especially when different archeological sites are more or less uniformly distributed in time are available. The disadvantage in that case is that data had to be relocated to a single reference site. The proximity of the reference locality Paris to Belgium makes that we used the French archaeomagnetic SV curve for the last three millennia up to the present for archaeomagnetic dating undated baked structures. In total, 85 baked structures have been examined, unearthed in 24 archaeological sites of the territory of Belgium. The ChRM of each sample was obtained by principal component analysis for at least three demagnetisation steps (Kirschvink 1980). Except for some outliers, the ChRM directions are very coherent with a high confidence factor (α95archaeomagnetism. At present, only six baked structures were dated radiometrically and may be considered as reference data for a limited area about 30500 km2 in Western Europe. The ultimate aim is to construct an archaeomagnetic SV curve for Belgium with Uccle as reference locality, where the first measurement of the geomagnetic field was done in 1895. This curve would include all the available reference data in a radius of about 500 km around Uccle. Keywords: secular variation, archaeomagnetic dating, Belgium.

  20. The aeolian dust accumulation curve

    NARCIS (Netherlands)

    Goossens, D.

    2001-01-01

    This article presents a simple physical concept of aeolian dust accumulation, based on the behaviour of the subprocesses of dust deposition and dust erosion. The concept is tested in an aeolian dust wind tunnel. The agreement between the accumulation curve predicted by the model and the accumulation

  1. A Curve for all Reasons

    Indian Academy of Sciences (India)

    The cause-effect relationship for a wide variety of biologi- cal processes from molecular to ecosystem levels can be described by a curvilinear function called the rectangular hyperbola. Although a simple algebraic equation adequately describes this curve, biological models have generated different equations incorporating ...

  2. Survival curves for irradiated cells

    International Nuclear Information System (INIS)

    Gibson, D.K.

    1975-01-01

    The subject of the lecture is the probability of survival of biological cells which have been subjected to ionising radiation. The basic mathematical theories of cell survival as a function of radiation dose are developed. A brief comparison with observed survival curves is made. (author)

  3. Texas curve margin of safety.

    Science.gov (United States)

    2013-01-01

    This software can be used to assist with the assessment of margin of safety for a horizontal curve. It is intended for use by engineers and technicians responsible for safety analysis or management of rural highway pavement or traffic control devices...

  4. Ultrasonic Fetal Cephalometry: Percentiles Curve

    Science.gov (United States)

    Flamme, P.

    1972-01-01

    Measurements by ultrasound of the biparietal diameter of the fetal head during pregnancy are a reliable guide to fetal growth. As a ready means of comparison with the normal we constructed from 4,170 measurements in 1,394 cases a curve showing the percentiles distribution of biparietal diameters for each week of gestation. PMID:5070162

  5. Interpolation and Polynomial Curve Fitting

    Science.gov (United States)

    Yang, Yajun; Gordon, Sheldon P.

    2014-01-01

    Two points determine a line. Three noncollinear points determine a quadratic function. Four points that do not lie on a lower-degree polynomial curve determine a cubic function. In general, n + 1 points uniquely determine a polynomial of degree n, presuming that they do not fall onto a polynomial of lower degree. The process of finding such a…

  6. The Qualitative Analysis of Theoretic Curves Generated by Linear Viscoelasticity Constitutive Equation

    Directory of Open Access Journals (Sweden)

    A. V. Khohlov

    2016-01-01

    Full Text Available The article analyses a one-dimensional linear integral constitutive equation of viscoelasticity with an arbitrary creep compliance function in order to reveal its abilities to describe the set of basic rheological phenomena pertaining to viscoelastoplastic materials at a constant temperature. General equations and basic properties of its quasi-static theoretic curves (i.e. stress-strain curves at constant strain or stress rates, creep, creep recovery, creep curves at piecewise-constant stress and ramp relaxation curves generated by the linear constitutive equation are derived and studied analytically. Their dependences on a creep function and relaxation modulus and on the loading program parameters are examined.The qualitative properties of the theoretic curves are compared to the typical properties of viscoelastoplastic materials test curves to reveal the mechanical effects, which the linear viscoelasticity theory cannot simulate and to find out convenient experimental indicators marking the field of its applicability or non-applicability. The minimal set of general restrictions that should be imposed on a creep and relaxation functions to provide an adequate description of typical test curves of viscoelastoplastic materials is formulated. It is proved, in particular, that an adequate simulation of typical experimental creep recovery curves requires that the derivative of a creep function should not increase at any point. This restriction implies that the linear viscoelasticity theory yields theoretical creep curves with non-increasing creep rate only and it cannot simulate materials demonstrating an accelerated creep stage. It is also proved that the linear viscoelasticity cannot simulate materials with experimental stress-strain curves possessing a maximum point or concave-up segment and materials exhibiting equilibrium modulus dependence on the strain rate or negative rate sensitivity.Similar qualitative analysis seems to be an important

  7. A catalog of special plane curves

    CERN Document Server

    Lawrence, J Dennis

    2014-01-01

    Among the largest, finest collections available-illustrated not only once for each curve, but also for various values of any parameters present. Covers general properties of curves and types of derived curves. Curves illustrated by a CalComp digital incremental plotter. 12 illustrations.

  8. Computation of undulator tuning curves

    International Nuclear Information System (INIS)

    Dejus, Roger J.

    1997-01-01

    Computer codes for fast computation of on-axis brilliance tuning curves and flux tuning curves have been developed. They are valid for an ideal device (regular planar device or a helical device) using the Bessel function formalism. The effects of the particle beam emittance and the beam energy spread on the spectrum are taken into account. The applicability of the codes and the importance of magnetic field errors of real insertion devices are addressed. The validity of the codes has been experimentally verified at the APS and observed discrepancies are in agreement with predicted reduction of intensities due to magnetic field errors. The codes are distributed as part of the graphical user interface XOP (X-ray OPtics utilities), which simplifies execution and viewing of the results

  9. Invariance for Single Curved Manifold

    KAUST Repository

    Castro, Pedro Machado Manhaes de

    2012-08-01

    Recently, it has been shown that, for Lambert illumination model, solely scenes composed by developable objects with a very particular albedo distribution produce an (2D) image with isolines that are (almost) invariant to light direction change. In this work, we provide and investigate a more general framework, and we show that, in general, the requirement for such in variances is quite strong, and is related to the differential geometry of the objects. More precisely, it is proved that single curved manifolds, i.e., manifolds such that at each point there is at most one principal curvature direction, produce invariant is surfaces for a certain relevant family of energy functions. In the three-dimensional case, the associated energy function corresponds to the classical Lambert illumination model with albedo. This result is also extended for finite-dimensional scenes composed by single curved objects. © 2012 IEEE.

  10. A curved resonant flexoelectric actuator

    Science.gov (United States)

    Zhang, Shuwen; Liu, Kaiyuan; Xu, Minglong; Shen, Shengping

    2017-08-01

    Flexoelectricity is an electro-mechanical coupling effect that exists in all dielectrics and has the potential to replace piezoelectric actuating on the microscale. In this letter, a curved flexoelectric actuator with non-polarized polyvinylidene fluoride is presented and shown to exhibit good electro-mechanical properties. This provides experimental support for a body of theoretical research into converse flexoelectricity in polymeric materials. In addition, this work demonstrates the feasibility of lead-free microscale actuating without piezoelectricity.

  11. Active Particles on Curved Surfaces

    OpenAIRE

    Fily, Yaouen; Baskaran, Aparna; Hagan, Michael F.

    2016-01-01

    Recent studies have highlighted the sensitivity of active matter to boundaries and their geometries. Here we develop a general theory for the dynamics and statistics of active particles on curved surfaces and illustrate it on two examples. We first show that active particles moving on a surface with no ability to probe its curvature only exhibit steady-state inhomogeneities in the presence of orientational order. We then consider a strongly confined 3D ideal active gas and compute its steady-...

  12. Growth curves for Laron syndrome.

    Science.gov (United States)

    Laron, Z; Lilos, P; Klinger, B

    1993-06-01

    Growth curves for children with Laron syndrome were constructed on the basis of repeated measurements made throughout infancy, childhood, and puberty in 24 (10 boys, 14 girls) of the 41 patients with this syndrome investigated in our clinic. Growth retardation was already noted at birth, the birth length ranging from 42 to 46 cm in the 12/20 available measurements. The postnatal growth curves deviated sharply from the normal from infancy on. Both sexes showed no clear pubertal spurt. Girls completed their growth between the age of 16-19 years to a final mean (SD) height of 119 (8.5) cm whereas the boys continued growing beyond the age of 20 years, achieving a final height of 124 (8.5) cm. At all ages the upper to lower body segment ratio was more than 2 SD above the normal mean. These growth curves constitute a model not only for primary, hereditary insulin-like growth factor-I (IGF-I) deficiency (Laron syndrome) but also for untreated secondary IGF-I deficiencies such as growth hormone gene deletion and idiopathic congenital isolated growth hormone deficiency. They should also be useful in the follow up of children with Laron syndrome treated with biosynthetic recombinant IGF-I.

  13. Projection-based curve clustering

    International Nuclear Information System (INIS)

    Auder, Benjamin; Fischer, Aurelie

    2012-01-01

    This paper focuses on unsupervised curve classification in the context of nuclear industry. At the Commissariat a l'Energie Atomique (CEA), Cadarache (France), the thermal-hydraulic computer code CATHARE is used to study the reliability of reactor vessels. The code inputs are physical parameters and the outputs are time evolution curves of a few other physical quantities. As the CATHARE code is quite complex and CPU time-consuming, it has to be approximated by a regression model. This regression process involves a clustering step. In the present paper, the CATHARE output curves are clustered using a k-means scheme, with a projection onto a lower dimensional space. We study the properties of the empirically optimal cluster centres found by the clustering method based on projections, compared with the 'true' ones. The choice of the projection basis is discussed, and an algorithm is implemented to select the best projection basis among a library of orthonormal bases. The approach is illustrated on a simulated example and then applied to the industrial problem. (authors)

  14. Dual Smarandache Curves and Smarandache Ruled Surfaces

    OpenAIRE

    Tanju KAHRAMAN; Mehmet ÖNDER; H. Hüseyin UGURLU

    2013-01-01

    In this paper, by considering dual geodesic trihedron (dual Darboux frame) we define dual Smarandache curves lying fully on dual unit sphere S^2 and corresponding to ruled surfaces. We obtain the relationships between the elements of curvature of dual spherical curve (ruled surface) x(s) and its dual Smarandache curve (Smarandache ruled surface) x1(s) and we give an example for dual Smarandache curves of a dual spherical curve.

  15. Parametrizations of elliptic curves by Shimura curves and by classical modular curves.

    Science.gov (United States)

    Ribet, K A; Takahashi, S

    1997-10-14

    Fix an isogeny class of semistable elliptic curves over Q. The elements A of have a common conductor N, which is a square-free positive integer. Let D be a divisor of N which is the product of an even number of primes--i.e., the discriminant of an indefinite quaternion algebra over Q. To D we associate a certain Shimura curve X(0)D(N/D), whose Jacobian is isogenous to an abelian subvariety of J0(N). There is a unique A [symbol; see text] A in for which one has a nonconstant map piD : X(0)D(N/D) --> A whose pullback A --> Pic0(X(0)D(N/D)) is injective. The degree of piD is an integer deltaD which depends only on D (and the fixed isogeny class A). We investigate the behavior of deltaD as D varies.

  16. MM98.83 Quantification of Combined Strain Paths

    DEFF Research Database (Denmark)

    Nielsen, Morten Sturgård; Lindegren, Maria; Wanheim, Tarras

    1998-01-01

    When working with processes where large plastic deformation occurs, a way of desribing the deformation process is to view the whole deformation history as a curve in the 6-dimensional shear strain normal strain space, henceforth called a strain history curve (SHC). This paper focuses on the SHC...... concept and the uniqueness of the SHC representation.The SHC may be used to give a useful representation of the total course of the deformation with respect to directions and magnitudes of strains, snd hence the development of the plastic properties, butmay also be used for developing variables describing...... 3D-plasticity. Adirect use of the SHC, is to measure the yield surface at different points at a SHC, thus establishing data describing the importance of strain rotations or even strain reversals within a process. Two subcases for displaying SHC will be mentioned:The plane strain case and the single...

  17. A note on families of fragility curves

    International Nuclear Information System (INIS)

    Kaplan, S.; Bier, V.M.; Bley, D.C.

    1989-01-01

    In the quantitative assessment of seismic risk, uncertainty in the fragility of a structural component is usually expressed by putting forth a family of fragility curves, with probability serving as the parameter of the family. Commonly, a lognormal shape is used both for the individual curves and for the expression of uncertainty over the family. A so-called composite single curve can also be drawn and used for purposes of approximation. This composite curve is often regarded as equivalent to the mean curve of the family. The equality seems intuitively reasonable, but according to the authors has never been proven. The paper presented proves this equivalence hypothesis mathematically. Moreover, the authors show that this equivalence hypothesis between fragility curves is itself equivalent to an identity property of the standard normal probability curve. Thus, in the course of proving the fragility curve hypothesis, the authors have also proved a rather obscure, but interesting and perhaps previously unrecognized, property of the standard normal curve

  18. NLINEAR - NONLINEAR CURVE FITTING PROGRAM

    Science.gov (United States)

    Everhart, J. L.

    1994-01-01

    A common method for fitting data is a least-squares fit. In the least-squares method, a user-specified fitting function is utilized in such a way as to minimize the sum of the squares of distances between the data points and the fitting curve. The Nonlinear Curve Fitting Program, NLINEAR, is an interactive curve fitting routine based on a description of the quadratic expansion of the chi-squared statistic. NLINEAR utilizes a nonlinear optimization algorithm that calculates the best statistically weighted values of the parameters of the fitting function and the chi-square that is to be minimized. The inputs to the program are the mathematical form of the fitting function and the initial values of the parameters to be estimated. This approach provides the user with statistical information such as goodness of fit and estimated values of parameters that produce the highest degree of correlation between the experimental data and the mathematical model. In the mathematical formulation of the algorithm, the Taylor expansion of chi-square is first introduced, and justification for retaining only the first term are presented. From the expansion, a set of n simultaneous linear equations are derived, which are solved by matrix algebra. To achieve convergence, the algorithm requires meaningful initial estimates for the parameters of the fitting function. NLINEAR is written in Fortran 77 for execution on a CDC Cyber 750 under NOS 2.3. It has a central memory requirement of 5K 60 bit words. Optionally, graphical output of the fitting function can be plotted. Tektronix PLOT-10 routines are required for graphics. NLINEAR was developed in 1987.

  19. Differential geometry curves, surfaces, manifolds

    CERN Document Server

    Kühnel, Wolfgang

    2015-01-01

    This carefully written book is an introduction to the beautiful ideas and results of differential geometry. The first half covers the geometry of curves and surfaces, which provide much of the motivation and intuition for the general theory. The second part studies the geometry of general manifolds, with particular emphasis on connections and curvature. The text is illustrated with many figures and examples. The prerequisites are undergraduate analysis and linear algebra. This new edition provides many advancements, including more figures and exercises, and-as a new feature-a good number of so

  20. LINS Curve in Romanian Economy

    Directory of Open Access Journals (Sweden)

    Emilian Dobrescu

    2016-02-01

    Full Text Available The paper presents theoretical considerations and empirical evidence to test the validity of the Laffer in Narrower Sense (LINS curve as a parabola with a maximum. Attention is focused on the so-called legal-effective tax gap (letg. The econometric application is based on statistical data (1990-2013 for Romania as an emerging European economy. Three cointegrating regressions (fully modified least squares, canonical cointegrating regression and dynamic least squares and three algorithms, which are based on instrumental variables (two-stage least squares, generalized method of moments, and limited information maximum likelihood, are involved.

  1. Principal Curves on Riemannian Manifolds

    DEFF Research Database (Denmark)

    Hauberg, Søren

    2015-01-01

    Euclidean statistics are often generalized to Riemannian manifolds by replacing straight-line interpolations with geodesic ones. While these Riemannian models are familiar-looking, they are restricted by the inflexibility of geodesics, and they rely on constructions which are optimal only...... in Euclidean domains. We consider extensions of Principal Component Analysis (PCA) to Riemannian manifolds. Classic Riemannian approaches seek a geodesic curve passing through the mean that optimize a criteria of interest. The requirements that the solution both is geodesic and must pass through the mean tend...

  2. Lightlike contractions in curved spacetime

    International Nuclear Information System (INIS)

    Aichelburg, P.C.; Embacher, F.

    1984-01-01

    The technique of lightlike contractions in flat and curved space is described. The method consists in boosting a classical field configuration to the velocity of light by an appropriate generalized Lorentz transformation. Within this framework the gravitational field of a massless neutral particle is a meaningful concept. For electrically charged particles, however, the field equations seem to prevent an analogous procedure. We thus conjecture that general relativity forbids the existance of charged point particles moving with the velocity of light. Further examples for lightlike contractions of a self-dual electromagnetic field and of a linearized Rarita-Schwinger (spin-3/2) field are given. (Author)

  3. Differential geometry and topology of curves

    CERN Document Server

    Animov, Yu

    2001-01-01

    Differential geometry is an actively developing area of modern mathematics. This volume presents a classical approach to the general topics of the geometry of curves, including the theory of curves in n-dimensional Euclidean space. The author investigates problems for special classes of curves and gives the working method used to obtain the conditions for closed polygonal curves. The proof of the Bakel-Werner theorem in conditions of boundedness for curves with periodic curvature and torsion is also presented. This volume also highlights the contributions made by great geometers. past and present, to differential geometry and the topology of curves.

  4. Numerical analysis of heat-curved I-girders

    Directory of Open Access Journals (Sweden)

    Antoine Gergess

    2017-10-01

    Full Text Available Heat curving is a practical and economical process used by steel fabricators for curving structural steel. In this method, the flange edges of a fabricated straight girder are asymmetrically heated to induce residual curvature on cooling. Available analytical methods for predicting the resulting residual stress, strain and curvature are complex and iterative because of the need to account for material and geometric non-linearity. This paper presents a single-step, non-iterative, numerical procedure for determining the effects of heat-curving on residual stress and strain based on a previously developed simplified analysis. Thermal equilibrium equations for idealized heating profiles are first recast in a general parametric form and then solved numerically for standard heating width and temperature using modern technical computing. The resulting solutions are expressed as polynomial functions to allow the solution space for the residual curvature to be graphically represented. Curvature predictions using this simplified approach are shown to be within 11% of measured values and within 5% of values obtained using more rigorous numerical methods.

  5. Flow characteristics of curved ducts

    Directory of Open Access Journals (Sweden)

    Rudolf P.

    2007-10-01

    Full Text Available Curved channels are very often present in real hydraulic systems, e.g. curved diffusers of hydraulic turbines, S-shaped bulb turbines, fittings, etc. Curvature brings change of velocity profile, generation of vortices and production of hydraulic losses. Flow simulation using CFD techniques were performed to understand these phenomena. Cases ranging from single elbow to coupled elbows in shapes of U, S and spatial right angle position with circular cross-section were modeled for Re = 60000. Spatial development of the flow was studied and consequently it was deduced that minor losses are connected with the transformation of pressure energy into kinetic energy and vice versa. This transformation is a dissipative process and is reflected in the amount of the energy irreversibly lost. Least loss coefficient is connected with flow in U-shape elbows, biggest one with flow in Sshape elbows. Finally, the extent of the flow domain influenced by presence of curvature was examined. This isimportant for proper placement of mano- and flowmeters during experimental tests. Simulations were verified with experimental results presented in literature.

  6. Classical optics and curved spaces

    International Nuclear Information System (INIS)

    Bailyn, M.; Ragusa, S.

    1976-01-01

    In the eikonal approximation of classical optics, the unit polarization 3-vector of light satisfies an equation that depends only on the index, n, of refraction. It is known that if the original 3-space line element is d sigma 2 , then this polarization direction propagates parallely in the fictitious space n 2 d sigma 2 . Since the equation depends only on n, it is possible to invent a fictitious curved 4-space in which the light performs a null geodesic, and the polarization 3-vector behaves as the 'shadow' of a parallely propagated 4-vector. The inverse, namely, the reduction of Maxwell's equation, on a curve 'dielectric free) space, to a classical space with dielectric constant n=(-g 00 ) -1 / 2 is well known, but in the latter the dielectric constant epsilon and permeability μ must also equal (-g 00 ) -1 / 2 . The rotation of polarization as light bends around the sun by utilizing the reduction to the classical space, is calculated. This (non-) rotation may then be interpreted as parallel transport in the 3-space n 2 d sigma 2 [pt

  7. Deformation Based Curved Shape Representation.

    Science.gov (United States)

    Demisse, Girum G; Aouada, Djamila; Ottersten, Bjorn

    2017-06-02

    In this paper, we introduce a deformation based representation space for curved shapes in Rn. Given an ordered set of points sampled from a curved shape, the proposed method represents the set as an element of a finite dimensional matrix Lie group. Variation due to scale and location are filtered in a preprocessing stage, while shapes that vary only in rotation are identified by an equivalence relationship. The use of a finite dimensional matrix Lie group leads to a similarity metric with an explicit geodesic solution. Subsequently, we discuss some of the properties of the metric and its relationship with a deformation by least action. Furthermore, invariance to reparametrization or estimation of point correspondence between shapes is formulated as an estimation of sampling function. Thereafter, two possible approaches are presented to solve the point correspondence estimation problem. Finally, we propose an adaptation of k-means clustering for shape analysis in the proposed representation space. Experimental results show that the proposed representation is robust to uninformative cues, e.g. local shape perturbation and displacement. In comparison to state of the art methods, it achieves a high precision on the Swedish and the Flavia leaf datasets and a comparable result on MPEG-7, Kimia99 and Kimia216 datasets.

  8. Smarandache Curves In Terms of Sabban Frame of Fixed Pole Curve

    Directory of Open Access Journals (Sweden)

    Süleyman Şenyurt

    2016-06-01

    Full Text Available In this paper, we study the special Smarandache curve interms of Sabban frame of Fixed Pole curve and we give some characterization of Smarandache curves. Besides, we illustrate examples of our results.

  9. Transition curves for highway geometric design

    CERN Document Server

    Kobryń, Andrzej

    2017-01-01

    This book provides concise descriptions of the various solutions of transition curves, which can be used in geometric design of roads and highways. It presents mathematical methods and curvature functions for defining transition curves. .

  10. Integration over Tropical Plane Curves and Ultradiscretization

    OpenAIRE

    Iwao, Shinsuke

    2008-01-01

    In this article we study holomorphic integrals on tropical plane curves in view of ultradiscretization. We prove that the lattice integrals over tropical curves can be obtained as a certain limit of complex integrals over Riemannian surfaces.

  11. Estimation method of the fracture resistance curve

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Sung Keun; Lee, Kwang Hyeon; Koo, Jae Mean; Seok, Chang Sung [Sungkyunkwan Univ., Suwon (Korea, Republic of); Park, Jae Sil [Samsung Electric Company, Suwon (Korea, Republic of)

    2008-07-01

    Fracture resistance curves for concerned materials are required in order to perform elastic-plastic fracture mechanical analysis. Fracture resistance curve is built with J-integral values and crack extension values. The objective of this paper is to propose the estimation method of the fracture resistance curve. The estimation method of the fracture resistance curve for the pipe specimen was proposed by the load ratio method from load - displacement data for the standard specimen.

  12. M-curves and symmetric products

    Indian Academy of Sciences (India)

    Indranil Biswas

    2017-08-03

    Aug 3, 2017 ... Since M-curves play a special role in the topology of real algebraic varieties, it is useful to have a criterion for M-curves. It was proved earlier that a curve defined over R is an. M-curve if and only if its Jacobian is an M-variety [5]. We use this result of [5] and the. Picard bundle to prove that the n-th symmetric ...

  13. Modeling fertility curves in Africa

    Directory of Open Access Journals (Sweden)

    Ezra Gayawan

    2010-02-01

    Full Text Available The modeling of fertility patterns is an essential method researchers use to understand world-wide population patterns. Various types of fertility models have been reported in the literature to capture the patterns specific to developed countries. While much effort has been put into reducing fertility rates in Africa, models which describe the fertility patterns have not been adequately described. This article presents a flexible parametric model that can adequately capture the varying patterns of the age-specific fertility curves of African countries. The model has parameters that are interpretable in terms of demographic indices. The performance of this model was compared with other commonly used models and Akaike's Information Criterion was used for selecting the model with best fit. The presented model was able to reproduce the empirical fertility data of 11 out of 15 countries better than the other models considered.

  14. Gelfond–Bézier curves

    KAUST Repository

    Ait-Haddou, Rachid

    2013-02-01

    We show that the generalized Bernstein bases in Müntz spaces defined by Hirschman and Widder (1949) and extended by Gelfond (1950) can be obtained as pointwise limits of the Chebyshev–Bernstein bases in Müntz spaces with respect to an interval [a,1][a,1] as the positive real number a converges to zero. Such a realization allows for concepts of curve design such as de Casteljau algorithm, blossom, dimension elevation to be transferred from the general theory of Chebyshev blossoms in Müntz spaces to these generalized Bernstein bases that we termed here as Gelfond–Bernstein bases. The advantage of working with Gelfond–Bernstein bases lies in the simplicity of the obtained concepts and algorithms as compared to their Chebyshev–Bernstein bases counterparts.

  15. Euler characteristics and elliptic curves.

    Science.gov (United States)

    Coates, J; Howson, S

    1997-10-14

    Let E be a modular elliptic curve over [symbol, see text], without complex multiplication; let p be a prime number where E has good ordinary reduction; and let Finfinity be the field obtained by adjoining [symbol, see text] to all p-power division points on E. Write Ginfinity for the Galois group of Finfinity over [symbol, see text]. Assume that the complex L-series of E over [symbol, see text] does not vanish at s = 1. If p >/= 5, we make a precise conjecture about the value of the Ginfinity-Euler characteristic of the Selmer group of E over Finfinity. If one makes a standard conjecture about the behavior of this Selmer group as a module over the Iwasawa algebra, we are able to prove our conjecture. The crucial local calculations in the proof depend on recent joint work of the first author with R. Greenberg.

  16. Separation control on curved boundaries

    Science.gov (United States)

    Kamal Kumar, R.; Mathur, Manikandan

    2017-11-01

    Flow separation and its characteristics are an important consideration in the field of bluff body aerodynamics. Specifically, the location and slope of the separation, and the size of the re-circulation bubble that forms downstream of the bluff body significantly affect the resulting aerodynamic forces. Recent theories based on dynamical systems (Haller, 2004) have established criteria based on wall-based quantities that identify the location and slope of separation in unsteady flows. In this work, we adapt the closed-loop separation control algorithm proposed by Alam, Liu & Haller (2006) to curved boundaries, and demonstrate the effectiveness of the same via numerical simulations on the flow past a cylinder in the vortex-shedding regime. Using appropriately placed wall-based actuators that use inputs from shear stress sensors placed between the actuators, we demonstrate that the separation characteristics including the re-circulation bubble length, can be desirably modified.

  17. Bacterial streamers in curved microchannels

    Science.gov (United States)

    Rusconi, Roberto; Lecuyer, Sigolene; Guglielmini, Laura; Stone, Howard

    2009-11-01

    Biofilms, generally identified as microbial communities embedded in a self-produced matrix of extracellular polymeric substances, are involved in a wide variety of health-related problems ranging from implant-associated infections to disease transmissions and dental plaque. The usual picture of these bacterial films is that they grow and develop on surfaces. However, suspended biofilm structures, or streamers, have been found in natural environments (e.g., rivers, acid mines, hydrothermal hot springs) and are always suggested to stem from a turbulent flow. We report the formation of bacterial streamers in curved microfluidic channels. By using confocal laser microscopy we are able to directly image and characterize the spatial and temporal evolution of these filamentous structures. Such streamers, which always connect the inner corners of opposite sides of the channel, are always located in the middle plane. Numerical simulations of the flow provide evidences for an underlying hydrodynamic mechanism behind the formation of the streamers.

  18. Plastic strain caused by contraction of pores in polycrystalline graphites

    International Nuclear Information System (INIS)

    Ioka, Ikuo; Yoda, Shinichi; Konishi, Takashi.

    1989-01-01

    The effects of porosity on mechanical properties and deformation behavior of four isotropic polycrystalline graphites were studied. The pore size distributions of the graphites were measured using a conventional mercury penetration technique. The average pore radius of ISO-88 graphite was about one-tenth of that of ISEM-1, IG-11 or IG-15 graphites. Young's modulus of the graphites decreased with increasing porosity. The stress-strain curve of each graphite was measured in its lateral and axial directions. Young's modulus of graphite decreased with increasing load. The plastic strain at a given compressive load was calculated from the stress-strain curve and the initial gradient of the unloading curve at the load. The ratio of lateral plastic strain to axial plastic strain for the graphites was less than 0.5, indicating that the volume of the graphites decreased during compressive loading. By assuming that the volume change was caused by contraction of pores, plastic strain associated with contraction of pores was calculated from the axial plastic strain and lateral plastic strain by slips along the basal planes. The plastic strain increased with increasing axial plastic strain and porosity of graphite. (author)

  19. AKLSQF - LEAST SQUARES CURVE FITTING

    Science.gov (United States)

    Kantak, A. V.

    1994-01-01

    The Least Squares Curve Fitting program, AKLSQF, computes the polynomial which will least square fit uniformly spaced data easily and efficiently. The program allows the user to specify the tolerable least squares error in the fitting or allows the user to specify the polynomial degree. In both cases AKLSQF returns the polynomial and the actual least squares fit error incurred in the operation. The data may be supplied to the routine either by direct keyboard entry or via a file. AKLSQF produces the least squares polynomial in two steps. First, the data points are least squares fitted using the orthogonal factorial polynomials. The result is then reduced to a regular polynomial using Sterling numbers of the first kind. If an error tolerance is specified, the program starts with a polynomial of degree 1 and computes the least squares fit error. The degree of the polynomial used for fitting is then increased successively until the error criterion specified by the user is met. At every step the polynomial as well as the least squares fitting error is printed to the screen. In general, the program can produce a curve fitting up to a 100 degree polynomial. All computations in the program are carried out under Double Precision format for real numbers and under long integer format for integers to provide the maximum accuracy possible. AKLSQF was written for an IBM PC X/AT or compatible using Microsoft's Quick Basic compiler. It has been implemented under DOS 3.2.1 using 23K of RAM. AKLSQF was developed in 1989.

  20. Sibling curves of quadratic polynomials | Wiggins | Quaestiones ...

    African Journals Online (AJOL)

    Sibling curves were demonstrated in [1, 2] as a novel way to visualize the zeroes of real valued functions. In [3] it was shown that a polynomial of degree n has n sibling curves. This paper focuses on the algebraic and geometric properites of the sibling curves of real and complex quadratic polynomials. Key words: Quadratic ...

  1. Legendre Elliptic Curves over Finite Fields

    NARCIS (Netherlands)

    Auer, Roland; Top, Jakob

    2002-01-01

    We show that every elliptic curve over a finite field of odd characteristic whose number of rational points is divisible by 4 is isogenous to an elliptic curve in Legendre form, with the sole exception of a minimal respectively maximal elliptic curve. We also collect some results concerning the

  2. Cubic spline functions for curve fitting

    Science.gov (United States)

    Young, J. D.

    1972-01-01

    FORTRAN cubic spline routine mathematically fits curve through given ordered set of points so that fitted curve nearly approximates curve generated by passing infinite thin spline through set of points. Generalized formulation includes trigonometric, hyperbolic, and damped cubic spline fits of third order.

  3. Trigonometric Characterization of Some Plane Curves

    Indian Academy of Sciences (India)

    IAS Admin

    (Figure 1). A relation between tan θ and tanψ gives the trigonometric equation of the family of curves. In this article, trigonometric equations of some known plane curves are deduced and it is shown that these equations reveal some geometric characteristics of the families of the curves under consideration. In Section 2,.

  4. Holomorphic curves in exploded manifolds: Kuranishi structure

    OpenAIRE

    Parker, Brett

    2013-01-01

    This paper constructs a Kuranishi structure for the moduli stack of holomorphic curves in exploded manifolds. To avoid some technicalities of abstract Kuranishi structures, we embed our Kuranishi structure inside a moduli stack of curves. The construction also works for the moduli stack of holomorphic curves in any compact symplectic manifold.

  5. Automated Blazar Light Curves Using Machine Learning

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Spencer James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-07-27

    This presentation describes a problem and methodology pertaining to automated blazar light curves. Namely, optical variability patterns for blazars require the construction of light curves and in order to generate the light curves, data must be filtered before processing to ensure quality.

  6. Investigation of stress–strain models for confined high strength ...

    Indian Academy of Sciences (India)

    The ascending branch of stress–strain curves depended on the ratio of confinement reinforcement was similar to the modified Kent–Park model and the descending branch similar to the Nagashima model. Keywords. High strength concrete; confined concrete; stress–strain models; ductility toughness. 1. Introduction.

  7. Method of construction spatial transition curve

    Directory of Open Access Journals (Sweden)

    S.V. Didanov

    2013-04-01

    Full Text Available Purpose. The movement of rail transport (speed rolling stock, traffic safety, etc. is largely dependent on the quality of the track. In this case, a special role is the transition curve, which ensures smooth insertion of the transition from linear to circular section of road. The article deals with modeling of spatial transition curve based on the parabolic distribution of the curvature and torsion. This is a continuation of research conducted by the authors regarding the spatial modeling of curved contours. Methodology. Construction of the spatial transition curve is numerical methods for solving nonlinear integral equations, where the initial data are taken coordinate the starting and ending points of the curve of the future, and the inclination of the tangent and the deviation of the curve from the tangent plane at these points. System solutions for the numerical method are the partial derivatives of the equations of the unknown parameters of the law of change of torsion and length of the transition curve. Findings. The parametric equations of the spatial transition curve are calculated by finding the unknown coefficients of the parabolic distribution of the curvature and torsion, as well as the spatial length of the transition curve. Originality. A method for constructing the spatial transition curve is devised, and based on this software geometric modeling spatial transition curves of railway track with specified deviations of the curve from the tangent plane. Practical value. The resulting curve can be applied in any sector of the economy, where it is necessary to ensure a smooth transition from linear to circular section of the curved space bypass. An example is the transition curve in the construction of the railway line, road, pipe, profile, flat section of the working blades of the turbine and compressor, the ship, plane, car, etc.

  8. Power forward curves: a managerial perspective

    International Nuclear Information System (INIS)

    Nagarajan, Shankar

    1999-01-01

    This chapter concentrates on managerial application of power forward curves, and examines the determinants of electricity prices such as transmission constraints, its inability to be stored in a conventional way, its seasonality and weather dependence, the generation stack, and the swing risk. The electricity forward curve, classical arbitrage, constructing a forward curve, volatilities, and electricity forward curve models such as the jump-diffusion model, the mean-reverting heteroscedastic volatility model, and an econometric model of forward prices are examined. A managerial perspective of the applications of the forward curve is presented covering plant valuation, capital budgeting, performance measurement, product pricing and structuring, asset optimisation, valuation of transmission options, and risk management

  9. Retrograde curves of solidus and solubility

    International Nuclear Information System (INIS)

    Vasil'ev, M.V.

    1979-01-01

    The investigation was concerned with the constitutional diagrams of the eutectic type with ''retrograde solidus'' and ''retrograde solubility curve'' which must be considered as diagrams with degenerate monotectic transformation. The solidus and the solubility curves form a retrograde curve with a common retrograde point representing the solubility maximum. The two branches of the Aetrograde curve can be described with the aid of two similar equations. Presented are corresponding equations for the Cd-Zn system and shown is the possibility of predicting the run of the solubility curve

  10. Beryllium strain under dynamic loading

    Directory of Open Access Journals (Sweden)

    Pushkov Victor

    2015-01-01

    Full Text Available There are some data (not much on dynamic characteristics of beryllium that are important, for example, when estimating construction performance at NPP emergencies. A number of data on stress-strain curves, spall strength, shear strength, fracture and structure responses of shock loaded beryllium have obtained in US and Russian laboratories. For today the model description of this complex metal behavior does not have a reasonable agreement with the experimental data, thus a wider spectrum of experimental data is required. This work presents data on dynamic compression-test diagrams of Russian beryllium. Experiments are performed using Hopkinson bar method (SHPB. Strain rates were ε ∼ 103 s−1.

  11. High strain-rate compressive behavior and constitutive modeling of selected polymers

    Directory of Open Access Journals (Sweden)

    Yokoyama T.

    2012-08-01

    Full Text Available The present paper deals with constitutive modeling of the compressive stress-strain behavior of selected polymers at strain rates from 10−3 to 103/s using a modified Ramberg-Osgood equation. High strain-rate compressive stress-strain curves for four different commercially available extruded polymers are determined on the standard split Hopkinson pressure bar. The low and intermediate strain-rates compressive stress-strain relations are measured in an Instron testing machine. The five parameters for the modified Ramberg-Osgood equation are determined by fitting to the experimental compressive stress-strain data using a least-squares fit. The compressive stress-strain curves at three different strain rates derived from the modified Ramberg-Osgood models are compared with the experimental results. It is shown that the compressive stress-strain behavior during loading process can be successfully predicted by the modified Ramberg-Osgood equation.

  12. Constitutive relation for rheological processes with known loading history. Creep and long-term strength curves

    Science.gov (United States)

    Khokhlov, A. V.

    2008-04-01

    In the present paper, we propose and study a nonlinear constitutive relation for describing the one-dimensional isothermal rheological processes with monotone loading history in viscoelastoplastic materials. This relation presents the strain at any time moment in terms of the history of variations in the stress and its derivative by means of two integral operators and contains two material functions of the same real argument and ten material parameters determined by the results of tests on material creeping, long-term strength, and strain at a constant loading rate. Under minimal a priori restrictions on the material parameters of the model, we derive the equations of strain, creep, relaxation, and long-term strength curves, analytically study the dependencies of their properties on parameters, and find necessary restrictions on the material parameters and functions ensuring an adequate description of the mechanical behavior of materials (the typical qualitative properties of experimental strain, creep, relaxation, and long-term strength curves). To model the long-term strength in creeping, we propose two parametric families of fracture criteria under monotone uniaxial strain, which are related to the strain criterion but take into account the history of the strain increase by means of special integral operators relating this history to the damage measure. We prove that the constitutive relation thus constructed, along with the proposed fracture criteria, leads to theoretical long-term strength curves with the same qualitative properties as the experimental curves of a majority of metals. Thus, an analysis of the properties of the proposed constitutive relation shows that it allows one to perform an adequate simulation not only of several effects of rheological behavior of viscoelastoplastic materials but of the entire complex of effects such as the strain dependence on the stress and the stress rate, relaxation, creeping, the creep rate dependence on the stress

  13. Shaking Table Tests of Curved Bridge considering Bearing Friction Sliding Isolation

    Directory of Open Access Journals (Sweden)

    Lei Yan

    2016-01-01

    Full Text Available Specific to severe damage to curved bridges in earthquakes caused by the excessive force of the fixed bearings and piers, a new seismic design method on curved bridges considering bearing friction sliding isolation is proposed in this paper. Seismic model bridge and isolation model bridge with similarity ratio of 1/20 were made and the shaking table comparison test was conducted. The experimental results show that the isolation model curved bridge suffered less seismic damage than the seismic model curved bridge. The fundamental frequencies of the seismic model bridge and isolation model bridge decreased and the damping ratio increased with the increase of seismic intensity. Compared with seismic curved bridge, the maximum reduction rates of peak acceleration along the radial and tangential directions on the top of pier of the isolation model curved bridge were 47.3% and 55.5%, respectively, and the maximum reduction rate of the peak strain on the bottom of pier of the isolation model curved bridge was 43.4%. For the isolation model curved bridge, the maximum reduction rate of peak acceleration on the top of pier was 24.6% compared with that on the bottom of pier. The study results can provide experimental basis for the seismic design of curved bridges.

  14. Page curves for tripartite systems

    International Nuclear Information System (INIS)

    Hwang, Junha; Lee, Deok Sang; Nho, Dongju; Oh, Jeonghun; Park, Hyosub; Zoe, Heeseung; Yeom, Dong-han

    2017-01-01

    We investigate information flow and Page curves for tripartite systems. We prepare a tripartite system (say, A , B , and C ) of a given number of states and calculate information and entropy contents by assuming random states. Initially, every particle was in A (this means a black hole), and as time goes on, particles move to either B (this means Hawking radiation) or C (this means a broadly defined remnant, including a non-local transport of information, the last burst, an interior large volume, or a bubble universe, etc). If the final number of states of the remnant is smaller than that of Hawking radiation, then information will be stored by both the radiation and the mutual information between the radiation and the remnant, while the remnant itself does not contain information. On the other hand, if the final number of states of the remnant is greater than that of Hawking radiation, then the radiation contains negligible information, while the remnant and the mutual information between the radiation and the remnant contain information. Unless the number of states of the remnant is large enough compared to the entropy of the black hole, Hawking radiation must contain information; and we meet the menace of black hole complementarity again. Therefore, this contrasts the tension between various assumptions and candidates of the resolution of the information loss problem. (paper)

  15. Localized qubits in curved spacetimes

    Science.gov (United States)

    Palmer, Matthew C.; Takahashi, Maki; Westman, Hans F.

    2012-04-01

    We provide a systematic and self-contained exposition of the subject of localized qubits in curved spacetimes. This research was motivated by a simple experimental question: if we move a spatially localized qubit, initially in a state |ψ1>, along some spacetime path Γ from a spacetime point x1 to another point x2, what will the final quantum state |ψ2> be at point x2? This paper addresses this question for two physical realizations of the qubit: spin of a massive fermion and polarization of a photon. Our starting point is the Dirac and Maxwell equations that describe respectively the one-particle states of localized massive fermions and photons. In the WKB limit we show how one can isolate a two-dimensional quantum state which evolves unitarily along Γ. The quantum states for these two realizations are represented by a left-handed 2-spinor in the case of massive fermions and a four-component complex polarization vector in the case of photons. In addition we show how to obtain from this WKB approach a fully general relativistic description of gravitationally induced phases. We use this formalism to describe the gravitational shift in the Colella-Overhauser-Werner 1975 experiment. In the non-relativistic weak field limit our result reduces to the standard formula in the original paper. We provide a concrete physical model for a Stern-Gerlach measurement of spin and obtain a unique spin operator which can be determined given the orientation and velocity of the Stern-Gerlach device and velocity of the massive fermion. Finally, we consider multipartite states and generalize the formalism to incorporate basic elements from quantum information theory such as quantum entanglement, quantum teleportation, and identical particles. The resulting formalism provides a basis for exploring precision quantum measurements of the gravitational field using techniques from quantum information theory.

  16. Construction of calibration curve for accountancy tank

    International Nuclear Information System (INIS)

    Kato, Takayuki; Goto, Yoshiki; Nidaira, Kazuo

    2009-01-01

    Tanks are equipped in a reprocessing plant for accounting solution of nuclear material. The careful measurement of volume in tanks is very important to implement rigorous accounting of nuclear material. The calibration curve relating the volume and level of solution needs to be constructed, where the level is determined by differential pressure of dip tubes. Several calibration curves are usually employed, but it's not explicitly decided how many segment are used, where to select segment, or what should be the degree of polynomial curve. These parameters, i.e., segment and degree of polynomial curve are mutually interrelated to give the better performance of calibration curve. Here we present the construction technique of giving optimum calibration curves and their characteristics. (author)

  17. MICA: Multiple interval-based curve alignment

    Science.gov (United States)

    Mann, Martin; Kahle, Hans-Peter; Beck, Matthias; Bender, Bela Johannes; Spiecker, Heinrich; Backofen, Rolf

    2018-01-01

    MICA enables the automatic synchronization of discrete data curves. To this end, characteristic points of the curves' shapes are identified. These landmarks are used within a heuristic curve registration approach to align profile pairs by mapping similar characteristics onto each other. In combination with a progressive alignment scheme, this enables the computation of multiple curve alignments. Multiple curve alignments are needed to derive meaningful representative consensus data of measured time or data series. MICA was already successfully applied to generate representative profiles of tree growth data based on intra-annual wood density profiles or cell formation data. The MICA package provides a command-line and graphical user interface. The R interface enables the direct embedding of multiple curve alignment computation into larger analyses pipelines. Source code, binaries and documentation are freely available at https://github.com/BackofenLab/MICA

  18. Oxford International Conference on the Mechanical Properties of Materials at High Rates of Strain (4th) Held in Oxford, United Kingdom on 19-22 March 1989

    Science.gov (United States)

    1989-03-22

    strain-curve cannot be modelled. Therefore the dynamic calibration curves are calculated with the finite-element-code ABAQUS and dynamic stress-strain...strain/strain-rate analysis has been dune for a number of proportional strain-rate controlled paths using th2 computer code ABAQU . The finite elements...bending data in low rate tests at RT.) (ot; the tensile strength in tensile test, (j);; the tensile strength by Brazilian test.) - _ 40 Refractory Porous

  19. Regional Marginal Abatement Cost Curves for NOx

    Data.gov (United States)

    U.S. Environmental Protection Agency — Data underlying the figures included in the manuscript "Marginal abatement cost curve for NOx incorporating controls, renewable electricity, energy efficiency and...

  20. Plasticity dependent damage evolution in composites with strain-gradient effects

    DEFF Research Database (Denmark)

    Legarth, Brian Nyvang

    2015-01-01

    -drop is seen in the macroscopic stress-strain response curve, which defines the failure strain of the composite. It is shown, that decreasing the value of the new cohesive material length parameter will monotonically decrease the failure strain. On the other hand, the material length scale parameter...

  1. Extension of Ko Straight-Beam Displacement Theory to Deformed Shape Predictions of Slender Curved Structures

    Science.gov (United States)

    Ko, William L.; Fleischer, Van Tran

    2011-01-01

    The Ko displacement theory originally developed for shape predictions of straight beams is extended to shape predictions of curved beams. The surface strains needed for shape predictions were analytically generated from finite-element nodal stress outputs. With the aid of finite-element displacement outputs, mathematical functional forms for curvature-effect correction terms are established and incorporated into straight-beam deflection equations for shape predictions of both cantilever and two-point supported curved beams. The newly established deflection equations for cantilever curved beams could provide quite accurate shape predictions for different cantilever curved beams, including the quarter-circle cantilever beam. Furthermore, the newly formulated deflection equations for two-point supported curved beams could provide accurate shape predictions for a range of two-point supported curved beams, including the full-circular ring. Accuracy of the newly developed curved-beam deflection equations is validated through shape prediction analysis of curved beams embedded in the windward shallow spherical shell of a generic crew exploration vehicle. A single-point collocation method for optimization of shape predictions is discussed in detail

  2. NEW CONCEPTS AND TEST METHODS OF CURVE PROFILE AREA DENSITY IN SURFACE: ESTIMATION OF AREAL DENSITY ON CURVED SPATIAL SURFACE

    OpenAIRE

    Hong Shen

    2011-01-01

    The concepts of curve profile, curve intercept, curve intercept density, curve profile area density, intersection density in containing intersection (or intersection density relied on intersection reference), curve profile intersection density in surface (or curve intercept intersection density relied on intersection of containing curve), and curve profile area density in surface (AS) were defined. AS expressed the amount of curve profile area of Y phase in the unit containing surface area, S...

  3. Polar representation of centrifugal pump homologous curves

    International Nuclear Information System (INIS)

    Veloso, Marcelo Antonio; Mattos, Joao Roberto Loureiro de

    2008-01-01

    Essential for any mathematical model designed to simulate flow transient events caused by pump operations is the pump performance data. The performance of a centrifugal pump is characterized by four basic parameters: the rotational speed, the volumetric flow rate, the dynamic head, and the hydraulic torque. Any one of these quantities can be expressed as a function of any two others. The curves showing the relationships between these four variables are called the pump characteristic curves, also referred to as four-quadrant curves. The characteristic curves are empirically developed by the pump manufacturer and uniquely describe head and torque as functions of volumetric flow rate and rotation speed. Because of comprising a large amount of points, the four-quadrant configuration is not suitable for computational purposes. However, it can be converted to a simpler form by the development of the homologous curves, in which dynamic head and hydraulic torque ratios are expressed as functions of volumetric flow and rotation speed ratios. The numerical use of the complete set of homologous curves requires specification of sixteen partial curves, being eight for the dynamic head and eight for the hydraulic torque. As a consequence, the handling of homologous curves is still somewhat complicated. In solving flow transient problems that require the pump characteristic data for all the operation zones, the polar form appears as the simplest way to represent the homologous curves. In the polar method, the complete characteristics of a pump can be described by only two closed curves, one for the dynamic head and other for the hydraulic torque, both in function of a single angular coordinate defined adequately in terms of the quotient between volumetric flow ratio and rotation speed ratio. The usefulness and advantages of this alternative method are demonstrated through a practical example in which the homologous curves for a pump of the type used in the main coolant loops of a

  4. Evaluation of PCR and high-resolution melt curve analysis for differentiation of Salmonella isolates.

    Science.gov (United States)

    Saeidabadi, Mohammad Sadegh; Nili, Hassan; Dadras, Habibollah; Sharifiyazdi, Hassan; Connolly, Joanne; Valcanis, Mary; Raidal, Shane; Ghorashi, Seyed Ali

    2017-06-01

    Consumption of poultry products contaminated with Salmonella is one of the major causes of foodborne diseases worldwide and therefore detection and differentiation of Salmonella spp. in poultry is important. In this study, oligonucleotide primers were designed from hemD gene and a PCR followed by high-resolution melt (HRM) curve analysis was developed for rapid differentiation of Salmonella isolates. Amplicons of 228 bp were generated from 16 different Salmonella reference strains and from 65 clinical field isolates mainly from poultry farms. HRM curve analysis of the amplicons differentiated Salmonella isolates and analysis of the nucleotide sequence of the amplicons from selected isolates revealed that each melting curve profile was related to a unique DNA sequence. The relationship between reference strains and tested specimens was also evaluated using a mathematical model without visual interpretation of HRM curves. In addition, the potential of the PCR-HRM curve analysis was evaluated for genotyping of additional Salmonella isolates from different avian species. The findings indicate that PCR followed by HRM curve analysis provides a rapid and robust technique for genotyping of Salmonella isolates to determine the serovar/serotype.

  5. Comparison and evaluation of mathematical lactation curve ...

    African Journals Online (AJOL)

    p2492989

    and on the log of 305-d divided by day in lactation (linear and quadratic) were better than the Gamma function. A study of lactation curves in dairy cattle on farms in central Mexico showed that the Dijkstra function was superior to the Wood, Wilmink and Rook functions for describing the lactation curve (Val-. Arreola et al.

  6. Spectral Curves of Operators with Elliptic Coefficients

    Directory of Open Access Journals (Sweden)

    J. Chris Eilbeck

    2007-03-01

    Full Text Available A computer-algebra aided method is carried out, for determining geometric objects associated to differential operators that satisfy the elliptic ansatz. This results in examples of Lamé curves with double reduction and in the explicit reduction of the theta function of a Halphen curve.

  7. Inverse Problem for a Curved Quantum Guide

    Directory of Open Access Journals (Sweden)

    Laure Cardoulis

    2012-01-01

    Full Text Available We consider the Dirichlet Laplacian operator −Δ on a curved quantum guide in ℝ  n(n=2,3 with an asymptotically straight reference curve. We give uniqueness results for the inverse problem associated to the reconstruction of the curvature by using either observations of spectral data or a boot-strapping method.

  8. Deep-learnt classification of light curves

    DEFF Research Database (Denmark)

    Mahabal, Ashish; Gieseke, Fabian; Pai, Akshay Sadananda Uppinakudru

    2017-01-01

    Astronomy light curves are sparse, gappy, and heteroscedastic. As a result standard time series methods regularly used for financial and similar datasets are of little help and astronomers are usually left to their own instruments and techniques to classify light curves. A common approach is to d...

  9. Learning curves in energy planning models

    Energy Technology Data Exchange (ETDEWEB)

    Barreto, L.; Kypreos, S. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    This study describes the endogenous representation of investment cost learning curves into the MARKAL energy planning model. A piece-wise representation of the learning curves is implemented using Mixed Integer Programming. The approach is briefly described and some results are presented. (author) 3 figs., 5 refs.

  10. The Koch curve as a smooth manifold

    International Nuclear Information System (INIS)

    Epstein, Marcelo; Sniatycki, Jedrzej

    2008-01-01

    We show that there exists a homeomorphism between the closed interval [0,1] is contained in R and the Koch curve endowed with the subset topology of R 2 . We use this homeomorphism to endow the Koch curve with the structure of a smooth manifold with boundary

  11. Trigonometric Characterization of Some Plane Curves

    Indian Academy of Sciences (India)

    IAS Admin

    There is a way to describe a family of plane curves different from that using Cartesian or po- lar co-ordinates. This is a trigonometric equation involving two angles. In this article, we highlight the fact that trigonometric equations are conve- nient to describe certain one-parameter families of plane curves. In some cases, the ...

  12. Heterozygote PCR product melting curve prediction.

    Science.gov (United States)

    Dwight, Zachary L; Palais, Robert; Kent, Jana; Wittwer, Carl T

    2014-03-01

    Melting curve prediction of PCR products is limited to perfectly complementary strands. Multiple domains are calculated by recursive nearest neighbor thermodynamics. However, the melting curve of an amplicon containing a heterozygous single-nucleotide variant (SNV) after PCR is the composite of four duplexes: two matched homoduplexes and two mismatched heteroduplexes. To better predict the shape of composite heterozygote melting curves, 52 experimental curves were compared with brute force in silico predictions varying two parameters simultaneously: the relative contribution of heteroduplex products and an ionic scaling factor for mismatched tetrads. Heteroduplex products contributed 25.7 ± 6.7% to the composite melting curve, varying from 23%-28% for different SNV classes. The effect of ions on mismatch tetrads scaled to 76%-96% of normal (depending on SNV class) and averaged 88 ± 16.4%. Based on uMelt (www.dna.utah.edu/umelt/umelt.html) with an expanded nearest neighbor thermodynamic set that includes mismatched base pairs, uMelt HETS calculates helicity as a function of temperature for homoduplex and heteroduplex products, as well as the composite curve expected from heterozygotes. It is an interactive Web tool for efficient genotyping design, heterozygote melting curve prediction, and quality control of melting curve experiments. The application was developed in Actionscript and can be found online at http://www.dna.utah.edu/hets/. © 2013 WILEY PERIODICALS, INC.

  13. A minicourse on moduli of curves

    International Nuclear Information System (INIS)

    Looijenga, E.

    2000-01-01

    These are notes that accompany a short course given at the School on Algebraic Geometry 1999 at the ICTP, Trieste. A major goal is to outline various approaches to moduli spaces of curves. In the last part I discuss the algebraic classes that naturally live on these spaces; these can be thought of as the characteristic classes for bundles of curves. (author)

  14. Sibling curves of polynomials | Wiggins | Quaestiones Mathematicae

    African Journals Online (AJOL)

    Sibling curves were demonstrated in papers [2, 3] as a novel way to visualize the zeros of complex valued functions. In this paper, we continue the work done in those papers by focusing solely on polynomials. We proceed to prove that the number of sibling curves of a polynomial is the degree of the polynomial. Keywords: ...

  15. Measuring Model Rocket Engine Thrust Curves

    Science.gov (United States)

    Penn, Kim; Slaton, William V.

    2010-01-01

    This paper describes a method and setup to quickly and easily measure a model rocket engine's thrust curve using a computer data logger and force probe. Horst describes using Vernier's LabPro and force probe to measure the rocket engine's thrust curve; however, the method of attaching the rocket to the force probe is not discussed. We show how a…

  16. Curve Matching with Applications in Medical Imaging

    DEFF Research Database (Denmark)

    Bauer, Martin; Bruveris, Martins; Harms, Philipp

    2015-01-01

    In the recent years, Riemannian shape analysis of curves and surfaces has found several applications in medical image analysis. In this paper we present a numerical discretization of second order Sobolev metrics on the space of regular curves in Euclidean space. This class of metrics has several...

  17. Single curved fiber sedimentation under gravity

    Science.gov (United States)

    Xiaoying Rong; Dewei Qi; Junyong Zhu

    2005-01-01

    Dynamics of single curved fiber sedimentation under the gravity are simulated by using lattice Boltzmann method. The results of migration and rotation of the curved fiber at different Reynolds numbers are reported. The results show that the rotation and migration processes are sensitive to the curvature of the fiber.

  18. Wind Turbine Power Curves Incorporating Turbulence Intensity

    DEFF Research Database (Denmark)

    Sørensen, Emil Hedevang Lohse

    2014-01-01

    The performance of a wind turbine in terms of power production (the power curve) is important to the wind energy industry. The current IEC-61400-12-1 standard for power curve evaluation recognizes only the mean wind speed at hub height and the air density as relevant to the power production...

  19. Quantum curves and conformal field theory

    Science.gov (United States)

    Manabe, Masahide; Sułkowski, Piotr

    2017-06-01

    To a given algebraic curve we assign an infinite family of quantum curves (Schrödinger equations), which are in one-to-one correspondence with, and have the structure of, Virasoro singular vectors. For a spectral curve of a matrix model we build such quantum curves out of an appropriate representation of the Virasoro algebra, encoded in the structure of the α /β -deformed matrix integral and its loop equation. We generalize this construction to a large class of algebraic curves by means of a refined topological recursion. We also specialize this construction to various specific matrix models with polynomial and logarithmic potentials, and among other results, show that various ingredients familiar in the study of conformal field theory (Ward identities, correlation functions and a representation of Virasoro operators acting thereon, Belavin-Polyakov-Zamolodchikov equations) arise upon specialization of our formalism to the multi-Penner matrix model.

  20. Curved and conformal high-pressure vessel

    Science.gov (United States)

    Croteau, Paul F.; Kuczek, Andrzej E.; Zhao, Wenping

    2016-10-25

    A high-pressure vessel is provided. The high-pressure vessel may comprise a first chamber defined at least partially by a first wall, and a second chamber defined at least partially by the first wall. The first chamber and the second chamber may form a curved contour of the high-pressure vessel. A modular tank assembly is also provided, and may comprise a first mid tube having a convex geometry. The first mid tube may be defined by a first inner wall, a curved wall extending from the first inner wall, and a second inner wall extending from the curved wall. The first inner wall may be disposed at an angle relative to the second inner wall. The first mid tube may further be defined by a short curved wall opposite the curved wall and extending from the second inner wall to the first inner wall.

  1. Parametric representation of centrifugal pump homologous curves

    International Nuclear Information System (INIS)

    Veloso, Marcelo A.; Mattos, Joao R.L. de

    2015-01-01

    Essential for any mathematical model designed to simulate flow transient events caused by pump operations is the pump performance data. The performance of a centrifugal pump is characterized by four basic quantities: the rotational speed, the volumetric flow rate, the dynamic head, and the hydraulic torque. The curves showing the relationships between these four variables are called the pump characteristic curves. The characteristic curves are empirically developed by the pump manufacturer and uniquely describe head and torque as functions of volumetric flow rate and rotation speed. Because of comprising a large amount of points, this configuration is not suitable for computational purposes. However, it can be converted to a simpler form by the development of the homologous curves, in which dynamic head and hydraulic torque ratios are expressed as functions of volumetric flow and rotation speed ratios. The numerical use of the complete set of homologous curves requires specification of sixteen partial curves, being eight for the dynamic head and eight for the hydraulic torque. As a consequence, the handling of homologous curves is still somewhat complicated. In solving flow transient problems that require the pump characteristic data for all the operation zones, the parametric form appears as the simplest way to deal with the homologous curves. In this approach, the complete characteristics of a pump can be described by only two closed curves, one for the dynamic head and other for the hydraulic torque, both in function of a single angular coordinate defined adequately in terms of the quotient between volumetric flow ratio and rotation speed ratio. The usefulness and advantages of this alternative method are demonstrated through a practical example in which the homologous curves for a pump of the type used in the main coolant loops of a pressurized water reactor (PWR) are transformed to the parametric form. (author)

  2. Parametric representation of centrifugal pump homologous curves

    Energy Technology Data Exchange (ETDEWEB)

    Veloso, Marcelo A.; Mattos, Joao R.L. de, E-mail: velosom@cdtn.br, E-mail: jrmattos@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2015-07-01

    Essential for any mathematical model designed to simulate flow transient events caused by pump operations is the pump performance data. The performance of a centrifugal pump is characterized by four basic quantities: the rotational speed, the volumetric flow rate, the dynamic head, and the hydraulic torque. The curves showing the relationships between these four variables are called the pump characteristic curves. The characteristic curves are empirically developed by the pump manufacturer and uniquely describe head and torque as functions of volumetric flow rate and rotation speed. Because of comprising a large amount of points, this configuration is not suitable for computational purposes. However, it can be converted to a simpler form by the development of the homologous curves, in which dynamic head and hydraulic torque ratios are expressed as functions of volumetric flow and rotation speed ratios. The numerical use of the complete set of homologous curves requires specification of sixteen partial curves, being eight for the dynamic head and eight for the hydraulic torque. As a consequence, the handling of homologous curves is still somewhat complicated. In solving flow transient problems that require the pump characteristic data for all the operation zones, the parametric form appears as the simplest way to deal with the homologous curves. In this approach, the complete characteristics of a pump can be described by only two closed curves, one for the dynamic head and other for the hydraulic torque, both in function of a single angular coordinate defined adequately in terms of the quotient between volumetric flow ratio and rotation speed ratio. The usefulness and advantages of this alternative method are demonstrated through a practical example in which the homologous curves for a pump of the type used in the main coolant loops of a pressurized water reactor (PWR) are transformed to the parametric form. (author)

  3. Microstructural evolution in high strength materials at high strain rates

    Science.gov (United States)

    Bassim, M. N.; Bolduc, M.; Odeshi, A. G.; Mirfarkraei, S.

    2006-08-01

    High strength materials such as used as armor plate have been investigated in torsion using Split Hopkinson Bars for the purpose of obtaining stress-strain curves and for examining the mechanism of plastic deformation in terms of mechanical instability due to thermal softening at high strain rates. A comparative study of the plastic deformation behavior of RHA steel, Aluminum 5083 H131 alloy and Tungsten A90S alloy under the loading condition at high strain rates is carried out and the effect of strain rate on shear flow stress and stress-strain profiles is presented. Strain rate sensitivities of the materials are evaluated and discussed with respect to mechanical instability and adiabatic shear strain localization.

  4. Analysis of creep curves produced by the linear viscoelasticity theory under cyclic stepwise loadings

    Directory of Open Access Journals (Sweden)

    Andrew V. Khokhlov

    2017-07-01

    Full Text Available Basic qualitative properties of the creep curves generated by the linear integral constitutive relation of viscoelasticity (with an arbitrary creep compliance under cyclic piecewise-constant uni-axial loadings (with an arbitrary asymmetry stress ratio are studied analytically. General formulas and a number of exact two-sided bounds are obtained for maximal, minimal and ratcheting strain values during each cycle, for their sequences limits, for the rate of plastic (non-recoverable strain accumulation and for cyclic creep curve deviation from the creep curve at constant stress which is equal to the cycle mean stress. Their dependence on loading cycle parameters and creep compliance properties are analyzed. Monotonicity and convexity intervals of cyclic creep curves, sequences of maximal and minimal strain values and ratcheting strain sequence, their evolution with cycle number growth and conditions for their boundedness, monotonicity and convergence are examined. The linear viscoelasticity theory abilities for simulation of ratcheting, creep acceleration, cyclic hardening or softening and cyclic stability under symmetric cyclic loadings are considered. The analysis carried out revealed the importance of convexity restriction imposed on a creep compliance and the governing role of its derivative limit value at infinity. It is proved that the limit value equality to zero is the criterion for non-accumulation of plastic strain, for memory fading and for asymptotic symmetrization of cyclic creep curve deviation from the creep curve at the mean stress. The qualitative features of theoretic cyclic creep curves are compared to basic properties of typical test creep curves of viscoelastoplastic materials under cyclic multi-step uni-axial loadings in order to elucidate the linear theory applicability scope, to reveal its abilities to provide an adequate description of basic rheological phenomena related to cyclic creep and to develop techniques of

  5. Investigation of learning and experience curves

    Energy Technology Data Exchange (ETDEWEB)

    Krawiec, F.; Thornton, J.; Edesess, M.

    1980-04-01

    The applicability of learning and experience curves for predicting future costs of solar technologies is assessed, and the major test case is the production economics of heliostats. Alternative methods for estimating cost reductions in systems manufacture are discussed, and procedures for using learning and experience curves to predict costs are outlined. Because adequate production data often do not exist, production histories of analogous products/processes are analyzed and learning and aggregated cost curves for these surrogates estimated. If the surrogate learning curves apply, they can be used to estimate solar technology costs. The steps involved in generating these cost estimates are given. Second-generation glass-steel and inflated-bubble heliostat design concepts, developed by MDAC and GE, respectively, are described; a costing scenario for 25,000 units/yr is detailed; surrogates for cost analysis are chosen; learning and aggregate cost curves are estimated; and aggregate cost curves for the GE and MDAC designs are estimated. However, an approach that combines a neoclassical production function with a learning-by-doing hypothesis is needed to yield a cost relation compatible with the historical learning curve and the traditional cost function of economic theory.

  6. Modelling curves of manufacturing feasibilities and demand

    Directory of Open Access Journals (Sweden)

    Soloninko K.S.

    2017-03-01

    Full Text Available The authors research the issue of functional properties of curves of manufacturing feasibilities and demand. Settlement of the problem, and its connection with important scientific and practical tasks. According to its nature, the market economy is unstable and is in constant movement. Economy has an effective instrument for explanation of changes in economic environment; this tool is called the modelling of economic processes. The modelling of economic processes depends first and foremost on the building of economic model which is the base for the formalization of economic process, that is, the building of mathematical model. The effective means for formalization of economic process is the creation of the model of hypothetic or imaginary economy. The building of demand model is significant for the market of goods and services. The problem includes the receiving (as the result of modelling definite functional properties of curves of manufacturing feasibilities and demand according to which one can determine their mathematical model. Another problem lies in obtaining majorant properties of curves of joint demand on the market of goods and services. Analysis of the latest researches and publications. Many domestic and foreign scientists dedicated their studies to the researches and building of the models of curves of manufacturing feasibilities and demand. In spite of considerable work of the scientists, such problems as functional properties of the curves and their practical use in modelling. The purpose of the article is to describe functional properties of curves of manufacturing feasibilities and demand on the market of goods and services on the base of modelling of their building. Scientific novelty and practical value. The theoretical regulations (for functional properties of curves of manufacturing feasibilities and demand received as a result of the present research, that is convexity, give extra practical possibilities in a microeconomic

  7. Neck curve polynomials in neck rupture model

    International Nuclear Information System (INIS)

    Kurniadi, Rizal; Perkasa, Yudha S.; Waris, Abdul

    2012-01-01

    The Neck Rupture Model is a model that explains the scission process which has smallest radius in liquid drop at certain position. Old fashion of rupture position is determined randomly so that has been called as Random Neck Rupture Model (RNRM). The neck curve polynomials have been employed in the Neck Rupture Model for calculation the fission yield of neutron induced fission reaction of 280 X 90 with changing of order of polynomials as well as temperature. The neck curve polynomials approximation shows the important effects in shaping of fission yield curve.

  8. CRC standard curves and surfaces with Mathematica

    CERN Document Server

    von Seggern, David H

    2006-01-01

    Since the publication of the first edition, Mathematica® has matured considerably and the computing power of desktop computers has increased greatly. This enables the presentation of more complex curves and surfaces as well as the efficient computation of formerly prohibitive graphical plots. Incorporating both of these aspects, CRC Standard Curves and Surfaces with Mathematica®, Second Edition is a virtual encyclopedia of curves and functions that depicts nearly all of the standard mathematical functions rendered using Mathematica. While the easy-to-use format remains unchanged from the previ

  9. Morse theory on timelike and causal curves

    International Nuclear Information System (INIS)

    Everson, J.; Talbot, C.J.

    1976-01-01

    It is shown that the set of timelike curves in a globally hyperbolic space-time manifold can be given the structure of a Hilbert manifold under a suitable definition of 'timelike.' The causal curves are the topological closure of this manifold. The Lorentzian energy (corresponding to Milnor's energy, except that the Lorentzian inner product is used) is shown to be a Morse function for the space of causal curves. A fixed end point index theorem is obtained in which a lower bound for the index of the Hessian of the Lorentzian energy is given in terms of the sum of the orders of the conjugate points between the end points. (author)

  10. Replication and Analysis of Ebbinghaus' Forgetting Curve.

    Science.gov (United States)

    Murre, Jaap M J; Dros, Joeri

    2015-01-01

    We present a successful replication of Ebbinghaus' classic forgetting curve from 1880 based on the method of savings. One subject spent 70 hours learning lists and relearning them after 20 min, 1 hour, 9 hours, 1 day, 2 days, or 31 days. The results are similar to Ebbinghaus' original data. We analyze the effects of serial position on forgetting and investigate what mathematical equations present a good fit to the Ebbinghaus forgetting curve and its replications. We conclude that the Ebbinghaus forgetting curve has indeed been replicated and that it is not completely smooth but most probably shows a jump upwards starting at the 24 hour data point.

  11. Replication and Analysis of Ebbinghaus’ Forgetting Curve

    Science.gov (United States)

    Murre, Jaap M. J.; Dros, Joeri

    2015-01-01

    We present a successful replication of Ebbinghaus’ classic forgetting curve from 1880 based on the method of savings. One subject spent 70 hours learning lists and relearning them after 20 min, 1 hour, 9 hours, 1 day, 2 days, or 31 days. The results are similar to Ebbinghaus' original data. We analyze the effects of serial position on forgetting and investigate what mathematical equations present a good fit to the Ebbinghaus forgetting curve and its replications. We conclude that the Ebbinghaus forgetting curve has indeed been replicated and that it is not completely smooth but most probably shows a jump upwards starting at the 24 hour data point. PMID:26148023

  12. Replication and Analysis of Ebbinghaus' Forgetting Curve.

    Directory of Open Access Journals (Sweden)

    Jaap M J Murre

    Full Text Available We present a successful replication of Ebbinghaus' classic forgetting curve from 1880 based on the method of savings. One subject spent 70 hours learning lists and relearning them after 20 min, 1 hour, 9 hours, 1 day, 2 days, or 31 days. The results are similar to Ebbinghaus' original data. We analyze the effects of serial position on forgetting and investigate what mathematical equations present a good fit to the Ebbinghaus forgetting curve and its replications. We conclude that the Ebbinghaus forgetting curve has indeed been replicated and that it is not completely smooth but most probably shows a jump upwards starting at the 24 hour data point.

  13. Growth curves for twins in Slovenia.

    Science.gov (United States)

    Bricelj, Katja; Blickstein, Isaac; Bržan-Šimenc, Gabrijela; Janša, Vid; Lučovnik, Miha; Verdenik, Ivan; Trojner-Bregar, Andreja; Tul, Nataša

    2017-02-01

    Abnormalities of fetal growth are more common in twins. We introduce the growth curves for monitoring fetal growth in twin pregnancies in Slovenia. Slovenian National Perinatal Information System for the period between 2002 and 2010 was used to calculate birth weight percentiles for all live born twins for each week from 22nd to 40th week. The calculated percentiles of birth weight for all live-born twins in Slovenia served as the basis for drawing 'growth' curves. The calculated growth curves for twins will help accurately diagnose small or large twin fetuses for their gestational age in the native central European population.

  14. Reflected Light Curves of Extrasolar Planets

    Science.gov (United States)

    Green, D.; Matthews, J.; Kuschnig, R.; Seager, S.

    The planned launches of ultra-precise photometric satellites such as MOST, COROT and MONS should provide the first opportunity to study the reflected light curves from extrasolar planets. To predict the capabilities of these missions, we have constructed a series of models of such light curves, improving upon the Monte Carlo simulations by Seager et al. (2000). These models include more realistic features such limb darkening of the star and broad band photometry. For specific models, the resulting planet light curves exhibit unique behavior with the variation of radius, inclination and presence or absence of clouds.

  15. Constructing forward price curves in electricity markets

    DEFF Research Database (Denmark)

    Fleten, S.-E.; Lemming, Jørgen Kjærgaard

    2003-01-01

    We present and analyze a method for constructing approximated high-resolution forward price curves in electricity markets. Because a limited number of forward or futures contracts are traded in the market, only a limited picture of the theoretical continuous forward price curve is available...... to the analyst. Our method combines the information contained in observed bid and ask prices with information from the forecasts generated by bottom-up models. As an example, we use information concerning the shape of the seasonal variation from a bottom-up model to improve the forward price curve quoted...

  16. Constructing forward price curves in electricity markets

    International Nuclear Information System (INIS)

    Fleten, Stein-Erik; Lemming, Jacob

    2003-01-01

    We present and analyze a method for constructing approximated high-resolution forward price curves in electricity markets. Because a limited number of forward or futures contracts are traded in the market, only a limited picture of the theoretical continuous forward price curve is available to the analyst. Our method combines the information contained in observed bid and ask prices with information from the forecasts generated by bottom-up models. As an example, we use information concerning the shape of the seasonal variation from a bottom-up model to improve the forward price curve quoted on the Nordic power exchange

  17. Curves of restricted type in euclidean spaces

    Directory of Open Access Journals (Sweden)

    Bengü Kılıç Bayram

    2014-01-01

    Full Text Available Submanifolds of restricted type were introduced in [7]. In the present study we consider restricted type of curves in Em. We give some special examples. We also show that spherical curve in S2(r C E3 is of restricted type if and only if either ƒ(s is constant or a linear function of s of the form ƒ(s = ±s + b and every closed W - curve of rank k and of length 2(r in E2k is of restricted type.

  18. Strain histograms are equal to strain ratios in predicting malignancy in breast tumours

    Science.gov (United States)

    Ewertsen, Caroline; Sletting, Susanne; Talman, Maj-Lis; Vejborg, Ilse; Bachmann Nielsen, Michael

    2017-01-01

    Objectives To assess whether strain histograms are equal to strain ratios in predicting breast tumour malignancy and to see if either could be used to upgrade Breast Imaging Reporting and Data System (BI-RADS) 3 tumours for immediate biopsy. Methods Ninety-nine breast tumours were examined using B-mode BI-RADS scorings and strain elastography. Strain histograms and ratios were assessed, and areas- under-the-receiver-operating-characteristic-curve (AUROC) for each method calculated. In BI-RADS 3 tumours cut-offs for strain histogram and ratio values were calculated to see if some tumours could be upgraded for immediate biopsy. Linear regression was performed to evaluate the effect of tumour depth and size, and breast density on strain elastography. Results Forty-four of 99 (44.4%) tumours were malignant. AUROC of BI-RADS, strain histograms and strain ratios were 0.949, 0.830 and 0.794 respectively. There was no significant difference between AUROCs of strain histograms and strain ratios (P = 0.405), while they were both inferior to BI-RADS scoring (PBI-RADS 3 tumours were malignant. When cut-offs of 189 for strain histograms and 1.44 for strain ratios were used to upgrade BI-RADS 3 tumours, AUROCS were 0.961 (Strain histograms and BI-RADS) and 0.941 (Strain ratios and BI-RADS). None of them was significantly different from BI-RADS scoring alone (P = 0.249 and P = 0.414). Tumour size and depth, and breast density influenced neither strain histograms (P = 0.196, P = 0.115 and P = 0.321) nor strain ratios (P = 0.411, P = 0.596 and P = 0.321) Conclusion Strain histogram analyses are reliable and easy to do in breast cancer diagnosis and perform comparably to strain ratio analyses. No significant difference in AUROCs between BI-RADS scoring and elastography combined with BI-RADS scoring was found in this study. PMID:29073170

  19. Strain histograms are equal to strain ratios in predicting malignancy in breast tumours.

    Directory of Open Access Journals (Sweden)

    Jonathan Frederik Carlsen

    Full Text Available To assess whether strain histograms are equal to strain ratios in predicting breast tumour malignancy and to see if either could be used to upgrade Breast Imaging Reporting and Data System (BI-RADS 3 tumours for immediate biopsy.Ninety-nine breast tumours were examined using B-mode BI-RADS scorings and strain elastography. Strain histograms and ratios were assessed, and areas- under-the-receiver-operating-characteristic-curve (AUROC for each method calculated. In BI-RADS 3 tumours cut-offs for strain histogram and ratio values were calculated to see if some tumours could be upgraded for immediate biopsy. Linear regression was performed to evaluate the effect of tumour depth and size, and breast density on strain elastography.Forty-four of 99 (44.4% tumours were malignant. AUROC of BI-RADS, strain histograms and strain ratios were 0.949, 0.830 and 0.794 respectively. There was no significant difference between AUROCs of strain histograms and strain ratios (P = 0.405, while they were both inferior to BI-RADS scoring (P<0.001, P = 0.008. Four out of 26 BI-RADS 3 tumours were malignant. When cut-offs of 189 for strain histograms and 1.44 for strain ratios were used to upgrade BI-RADS 3 tumours, AUROCS were 0.961 (Strain histograms and BI-RADS and 0.941 (Strain ratios and BI-RADS. None of them was significantly different from BI-RADS scoring alone (P = 0.249 and P = 0.414. Tumour size and depth, and breast density influenced neither strain histograms (P = 0.196, P = 0.115 and P = 0.321 nor strain ratios (P = 0.411, P = 0.596 and P = 0.321.Strain histogram analyses are reliable and easy to do in breast cancer diagnosis and perform comparably to strain ratio analyses. No significant difference in AUROCs between BI-RADS scoring and elastography combined with BI-RADS scoring was found in this study.

  20. A computer program for plotting stress-strain data from compression, tension, and torsion tests of materials

    Science.gov (United States)

    Greenbaum, A.; Baker, D. J.; Davis, J. G., Jr.

    1974-01-01

    A computer program for plotting stress-strain curves obtained from compression and tension tests on rectangular (flat) specimens and circular-cross-section specimens (rods and tubes) and both stress-strain and torque-twist curves obtained from torsion tests on tubes is presented in detail. The program is written in FORTRAN 4 language for the Control Data 6000 series digital computer with the SCOPE 3.0 operating system and requires approximately 110000 octal locations of core storage. The program has the capability of plotting individual strain-gage outputs and/or the average output of several strain gages and the capability of computing the slope of a straight line which provides a least-squares fit to a specified section of the plotted curve. In addition, the program can compute the slope of the stress-strain curve at any point along the curve. The computer program input and output for three sample problems are presented.

  1. Technological change in energy systems. Learning curves, logistic curves and input-output coefficients

    International Nuclear Information System (INIS)

    Pan, Haoran; Koehler, Jonathan

    2007-01-01

    Learning curves have recently been widely adopted in climate-economy models to incorporate endogenous change of energy technologies, replacing the conventional assumption of an autonomous energy efficiency improvement. However, there has been little consideration of the credibility of the learning curve. The current trend that many important energy and climate change policy analyses rely on the learning curve means that it is of great importance to critically examine the basis for learning curves. Here, we analyse the use of learning curves in energy technology, usually implemented as a simple power function. We find that the learning curve cannot separate the effects of price and technological change, cannot reflect continuous and qualitative change of both conventional and emerging energy technologies, cannot help to determine the time paths of technological investment, and misses the central role of R and D activity in driving technological change. We argue that a logistic curve of improving performance modified to include R and D activity as a driving variable can better describe the cost reductions in energy technologies. Furthermore, we demonstrate that the top-down Leontief technology can incorporate the bottom-up technologies that improve along either the learning curve or the logistic curve, through changing input-output coefficients. An application to UK wind power illustrates that the logistic curve fits the observed data better and implies greater potential for cost reduction than the learning curve does. (author)

  2. Mesoscopic Features of Plastic Strain in Step Yield

    Science.gov (United States)

    Krishtal, M. M.

    2002-09-01

    A specially developed method for isolating the macroscopically homogeneous part of plastic strain in step yield (SY) of materials is used for analyzing stress-strain curves of alloy AMg5 obtained at various strain rates in the range of appearance of SY. It is shown that the beginning of the SY corresponds to the inflection point in the linear dependence of the true stresses ( S) on the true plastic strain ( e) in S - e 1/2 coordinates, which is identified as the appearance of a new individual strain stage caused by the change in the strain mechanism at the mesolevel. The established change in the strain mechanism is shown to consist in an abrupt growth of the elementary volume of plastic strain due to the appearance of a space-time correlation in the development of the strain microprocesses, which is responsible for macrolocalization and general loss of the stability of the strain. The developed experimental and computational method is used to determine the rate sensitivity of the strain resistance to step yield, which is a positive quantity that increases with the strain.

  3. Uncovering the skewness news impact curve

    Czech Academy of Sciences Publication Activity Database

    Anatolyev, Stanislav; Petukhov, A.

    2016-01-01

    Roč. 14, č. 4 (2016), s. 746-771 ISSN 1479-8409 Institutional support: RVO:67985998 Keywords : conditional skewness * news impact curve * stock returns Subject RIV: AH - Economics Impact factor: 1.800, year: 2016

  4. Twisted vector bundles on pointed nodal curves

    Indian Academy of Sciences (India)

    Abstract. Motivated by the quest for a good compactification of the moduli space of -bundles on a nodal curve we establish a striking relationship between Abramovich's and Vistoli's twisted bundles and Gieseker vector bundles.

  5. Safety evaluation of curve warning speed signs.

    Science.gov (United States)

    2011-06-01

    This report presents a review of a research effort to evaluate the safety implications of advisory speeds at horizontal curve locations on Oregon rural two-lane highways. The primary goals of this research effort were to characterize driving operatio...

  6. ARC Code TI: ROC Curve Code Augmentation

    Data.gov (United States)

    National Aeronautics and Space Administration — ROC (Receiver Operating Characteristic) curve Code Augmentation was written by Rodney Martin and John Stutz at NASA Ames Research Center and is a modification of ROC...

  7. Twisted Vector Bundles on Pointed Nodal Curves

    Indian Academy of Sciences (India)

    Abstract. Motivated by the quest for a good compactification of the moduli space of -bundles on a nodal curve we establish a striking relationship between Abramovich's and Vistoli's twisted bundles and Gieseker vector bundles.

  8. Automorphisms of double coverings of curves

    International Nuclear Information System (INIS)

    Torres, F.

    1994-11-01

    We study automorphisms of curves that commute with each other. We prove that the order and the number of fixed points of one of them satisfy certain relations involving those of the other. Then, we specialize our results to the case of double coverings of curves. For instance, if the genus of the curve is at least 4γ + 2 and γ >= 1 (γ = the genus of the covered curve) we prove that the order of an automorphism is bounded above by 2γ + 1 (resp. 4γ + 2) provided it is prime (resp. it has at least five fixed points). We also improve Farkas' bound on the number of fixed points namely 4γ + 4 by showing that it involves the order of the automorphism except in the case of even order when such an improvement is obtained provided the automorphism and the γ-involution has at least one common fixed point. (author). 15 refs

  9. On ``minimally curved spacetimes'' in general relativity

    OpenAIRE

    Dadhich, Naresh

    1997-01-01

    We consider a spacetime corresponding to uniform relativistic potential analogus to Newtonian potential as an example of ``minimally curved spacetime''. We also consider a radially symmetric analogue of the Rindler spacetime of uniform proper acceleration relative to infinity.

  10. Quaternion orders, quadratic forms, and Shimura curves

    CERN Document Server

    Alsina, Montserrat

    2004-01-01

    Shimura curves are a far-reaching generalization of the classical modular curves. They lie at the crossroads of many areas, including complex analysis, hyperbolic geometry, algebraic geometry, algebra, and arithmetic. The text provides an introduction to the subject from a theoretic and algorithmic perspective. The main topics covered in it are Shimura curves defined over the rational number field, the construction of their fundamental domains, and the determination of their complex multiplication points. The study of complex multiplication points in Shimura curves leads to the study of families of binary quadratic forms with algebraic coefficients and to their classification by arithmetic Fuchsian groups. In this regard, the authors develop a theory full of new possibilities which parallels Gauss' theory on the classification of binary quadratic forms with integral coefficients by the action of the modular group. Each topic covered in the book begins with a theoretical discussion followed by carefully worked...

  11. Uncovering the skewness news impact curve

    Czech Academy of Sciences Publication Activity Database

    Anatolyev, Stanislav; Petukhov, A.

    2016-01-01

    Roč. 14, č. 4 (2016), s. 746-771 ISSN 1479-8409 Institutional support: PRVOUK-P23 Keywords : conditional skewness * news impact curve * stock returns Subject RIV: AH - Economics Impact factor: 1.800, year: 2016

  12. Procedures for setting curve advisory speed.

    Science.gov (United States)

    2009-08-01

    The procedures described in this handbook are intended to improve consistency in curve signing and driver compliance with the advisory speed. The handbook describes guidelines for determining when an advisory speed is needed, criteria for identifying...

  13. Liquefaction Probability Curves for Surficial Geologic Units

    Science.gov (United States)

    Holzer, T. L.; Noce, T. E.; Bennett, M. J.

    2009-12-01

    Liquefaction probability curves that predict the probability of surface manifestations of earthquake-induced liquefaction are developed for 14 different surficial geologic deposits. The geologic units include alluvial fan, beach ridge, river delta, eolian dune, point bar, floodbasin, natural river levee, abandoned river channel, deep-water lake, lagoonal, sandy artificial fill, and valley train deposits. Probability is conditioned on earthquake magnitude and peak ground acceleration. Curves are developed for water table depths of 1.5 and 5.0 m. Probabilities were derived from complementary cumulative frequency distributions of the liquefaction potential index (LPI) that were computed from 935 cone penetration tests. Most of the curves can be fit with a 3-parameter logistic function, which facilitates computations of probability. For natural deposits with a water table at 1.5 m depth and subjected to an M7.5 earthquake with a PGA = 0.25 g, probabilities range from 0.5 for fluvial point bar, barrier island beach ridge, and deltaic deposits. Retrospective predictions of liquefaction during historical earthquakes based on the curves compare favorably to post-earthquake observations. We also have used the curves to assign ranges of liquefaction probabilities to the susceptibility categories proposed by Youd and Perkins (1978) for different geologic deposits. For the earthquake loading and conditions described above, probabilities range from 0-0.08 for low, 0.09-0.30 for moderate, 0.31-0.62 for high, to 0.63-1.00 for very high susceptibility. Liquefaction probability curves have two primary practical applications. First, the curves can be combined with seismic source characterizations to transform surficial geologic maps into probabilistic liquefaction hazard maps. Geographic specific curves are clearly desirable, but in the absence of such information, generic liquefaction probability curves provide a first approximation of liquefaction hazard. Such maps are useful both

  14. Neutron cross sections: Book of curves

    International Nuclear Information System (INIS)

    McLane, V.; Dunford, C.L.; Rose, P.F.

    1988-01-01

    Neuton Cross Sections: Book of Curves represents the fourth edition of what was previously known as BNL-325, Neutron Cross Sections, Volume 2, CURVES. Data is presented only for (i.e., intergrated) reaction cross sections (and related fission parameters) as a function of incident-neutron energy for the energy range 0.01 eV to 200 MeV. For the first time, isometric state production cross sections have been included. 11 refs., 4 figs

  15. Curves along which plane waves can interfere

    Energy Technology Data Exchange (ETDEWEB)

    Karp, S.N.; Machover, M.

    1977-07-01

    Partial results are given on a conjecture in inverse scattering theory concerning the interference of two-dimensional plane waves. The conjecture states that an odd number of plane waves of the same frequency can only cancel each other at isolated points and not along a simple continuous curve. It is partially confirmed here for curves which are nearly flat at some point. An analysis is also made for various possible nodes for an even number of plane waves.

  16. [Biomechanic principles of the sagittal compensating curve].

    Science.gov (United States)

    Kubein-Meesenburg, D; Nägerl, H; Fanghänel, J

    1990-07-01

    The alignment of the buccal teeth along the compensating curve is of functional importance. It is closely related with the functional gear system of anterior and posterior guidance. Measurements have shown that individual differences between masticatory systems are mainly attributable to functional parameters. Purely skeletal parameters are of comparatively little variability. The compensating curve may be regarded as a guiding element within a master gear systems which includes the gear system of anterior and posterior guidance.

  17. Replication and Analysis of Ebbinghaus? Forgetting Curve

    OpenAIRE

    Murre, Jaap M. J.; Dros, Joeri

    2015-01-01

    We present a successful replication of Ebbinghaus’ classic forgetting curve from 1880 based on the method of savings. One subject spent 70 hours learning lists and relearning them after 20 min, 1 hour, 9 hours, 1 day, 2 days, or 31 days. The results are similar to Ebbinghaus' original data. We analyze the effects of serial position on forgetting and investigate what mathematical equations present a good fit to the Ebbinghaus forgetting curve and its replications. We conclude that the Ebbingha...

  18. Curvature Entropy for Curved Profile Generation

    OpenAIRE

    Ujiie, Yoshiki; Kato, Takeo; Sato, Koichiro; Matsuoka, Yoshiyuki

    2012-01-01

    In a curved surface design, the overall shape features that emerge from combinations of shape elements are important. However, controlling the features of the overall shape in curved profiles is difficult using conventional microscopic shape information such as dimension. Herein two types of macroscopic shape information, curvature entropy and quadrature curvature entropy, quantitatively represent the features of the overall shape. The curvature entropy is calculated by the curvature distribu...

  19. Curved twistor spaces and H-space

    International Nuclear Information System (INIS)

    Tod, K.P.

    1980-01-01

    The curved twistor space construction of Penrose for anti-self-dual solutions to the Einstein vacuum equations is described. Curved twistor spaces are defined and it is shown with the aid of an example how to obtain them by deforming the complex structure of regions of flat twistor space. The connection of this procedure with Newman's H-space construction via asymptotic twistor space is outlined. (Auth.)

  20. Potential Energy Curve of N2 Revisited

    Czech Academy of Sciences Publication Activity Database

    Špirko, Vladimír; Xiangzhu, L.; Paldus, J.

    2011-01-01

    Roč. 76, č. 4 (2011), s. 327-341 ISSN 0010-0765 R&D Projects: GA MŠk LC512; GA ČR GAP208/11/0436 Institutional research plan: CEZ:AV0Z40550506 Keywords : reduced multireference coupled-cluster method * reduced potential curve method * nitrogen molecule potential energy curves Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.283, year: 2011

  1. Learning curves in health professions education.

    Science.gov (United States)

    Pusic, Martin V; Boutis, Kathy; Hatala, Rose; Cook, David A

    2015-08-01

    Learning curves, which graphically show the relationship between learning effort and achievement, are common in published education research but are not often used in day-to-day educational activities. The purpose of this article is to describe the generation and analysis of learning curves and their applicability to health professions education. The authors argue that the time is right for a closer look at using learning curves-given their desirable properties-to inform both self-directed instruction by individuals and education management by instructors.A typical learning curve is made up of a measure of learning (y-axis), a measure of effort (x-axis), and a mathematical linking function. At the individual level, learning curves make manifest a single person's progress towards competence including his/her rate of learning, the inflection point where learning becomes more effortful, and the remaining distance to mastery attainment. At the group level, overlaid learning curves show the full variation of a group of learners' paths through a given learning domain. Specifically, they make overt the difference between time-based and competency-based approaches to instruction. Additionally, instructors can use learning curve information to more accurately target educational resources to those who most require them.The learning curve approach requires a fine-grained collection of data that will not be possible in all educational settings; however, the increased use of an assessment paradigm that explicitly includes effort and its link to individual achievement could result in increased learner engagement and more effective instructional design.

  2. Verified Indifferentiable Hashing into Elliptic Curves

    OpenAIRE

    Barthe, Gilles; Grégoire, Benjamin; Heraud, Sylvain; Olmedo, Federico; Zanella-Béguelin, Santiago

    2012-01-01

    International audience; Many cryptographic systems based on elliptic curves are proven secure in the Random Oracle Model, assuming there exist probabilistic functions that map elements in some domain (e.g. bitstrings) onto uniformly and independently distributed points in a curve. When implementing such systems, and in order for the proof to carry over to the implementation, those mappings must be instantiated with concrete constructions whose behavior does not deviate significantly from rand...

  3. Constructing elliptic curves from Galois representations

    OpenAIRE

    Snowden, Andrew; Tsimerman, Jacob

    2017-01-01

    Given a non-isotrivial elliptic curve over an arithmetic surface, one obtains a lisse $\\ell$-adic sheaf of rank two over the surface. This lisse sheaf has a number of straightforward properties: cyclotomic determinant, finite ramification, rational traces of Frobenius, and somewhere not potentially good reduction. We prove that any lisse sheaf of rank two possessing these properties comes from an elliptic curve.

  4. Probing exoplanet clouds with optical phase curves.

    Science.gov (United States)

    Muñoz, Antonio García; Isaak, Kate G

    2015-11-03

    Kepler-7b is to date the only exoplanet for which clouds have been inferred from the optical phase curve--from visible-wavelength whole-disk brightness measurements as a function of orbital phase. Added to this, the fact that the phase curve appears dominated by reflected starlight makes this close-in giant planet a unique study case. Here we investigate the information on coverage and optical properties of the planet clouds contained in the measured phase curve. We generate cloud maps of Kepler-7b and use a multiple-scattering approach to create synthetic phase curves, thus connecting postulated clouds with measurements. We show that optical phase curves can help constrain the composition and size of the cloud particles. Indeed, model fitting for Kepler-7b requires poorly absorbing particles that scatter with low-to-moderate anisotropic efficiency, conclusions consistent with condensates of silicates, perovskite, and silica of submicron radii. We also show that we are limited in our ability to pin down the extent and location of the clouds. These considerations are relevant to the interpretation of optical phase curves with general circulation models. Finally, we estimate that the spherical albedo of Kepler-7b over the Kepler passband is in the range 0.4-0.5.

  5. Environmental bias and elastic curves on surfaces

    International Nuclear Information System (INIS)

    Guven, Jemal; María Valencia, Dulce; Vázquez-Montejo, Pablo

    2014-01-01

    The behavior of an elastic curve bound to a surface will reflect the geometry of its environment. This may occur in an obvious way: the curve may deform freely along directions tangent to the surface, but not along the surface normal. However, even if the energy itself is symmetric in the curve's geodesic and normal curvatures, which control these modes, very distinct roles are played by the two. If the elastic curve binds preferentially on one side, or is itself assembled on the surface, not only would one expect the bending moduli associated with the two modes to differ, binding along specific directions, reflected in spontaneous values of these curvatures, may be favored. The shape equations describing the equilibrium states of a surface curve described by an elastic energy accommodating environmental factors will be identified by adapting the method of Lagrange multipliers to the Darboux frame associated with the curve. The forces transmitted to the surface along the surface normal will be determined. Features associated with a number of different energies, both of physical relevance and of mathematical interest, are described. The conservation laws associated with trajectories on surface geometries exhibiting continuous symmetries are also examined. (paper)

  6. Geometric invariant theory for polarized curves

    CERN Document Server

    Bini, Gilberto; Melo, Margarida; Viviani, Filippo

    2014-01-01

    We investigate GIT quotients of polarized curves. More specifically, we study the GIT problem for the Hilbert and Chow schemes of curves of degree d and genus g in a projective space of dimension d-g, as d decreases with respect to g. We prove that the first three values of d at which the GIT quotients change are given by d=a(2g-2) where a=2, 3.5, 4. We show that, for a>4, L. Caporaso's results hold true for both Hilbert and Chow semistability. If 3.5curves. If 2curves. We also analyze in detail the critical values a=3.5 and a=4, where the Hilbert semistable locus is strictly smaller than the Chow semistable locus. As an application, we obtain three compactications of the universal Jacobian over the moduli space of stable curves, weakly-pseudo-stable curves and pseu...

  7. Piecewise power laws in individual learning curves.

    Science.gov (United States)

    Donner, Yoni; Hardy, Joseph L

    2015-10-01

    The notion that human learning follows a smooth power law (PL) of diminishing gains is well-established in psychology. This characteristic is observed when multiple curves are averaged, potentially masking more complex dynamics underpinning the curves of individual learners. Here, we analyzed 25,280 individual learning curves, each comprising 500 measurements of cognitive performance taken from four cognitive tasks. A piecewise PL (PPL) model explained the individual learning curves significantly better than a single PL, controlling for model complexity. The PPL model allows for multiple PLs connected at different points in the learning process. We also explored the transition dynamics between PL curve component pieces. Performance in later pieces typically surpassed that in earlier pieces, after a brief drop in performance at the transition point. The transition rate was negatively associated with age, even after controlling for overall performance. Our results suggest at least two processes at work in individual learning curves: locally, a gradual, smooth improvement, with diminishing gains within a specific strategy, which is modeled well as a PL; and globally, a discrete sequence of strategy shifts, in which each strategy is better in the long term than the ones preceding it. The piecewise extension of the classic PL of practice has implications for both individual skill acquisition and theories of learning.

  8. Global experience curves for wind farms

    International Nuclear Information System (INIS)

    Junginger, M.; Faaij, A.; Turkenburg, W.C.

    2005-01-01

    In order to forecast the technological development and cost of wind turbines and the production costs of wind electricity, frequent use is made of the so-called experience curve concept. Experience curves of wind turbines are generally based on data describing the development of national markets, which cause a number of problems when applied for global assessments. To analyze global wind energy price development more adequately, we compose a global experience curve. First, underlying factors for past and potential future price reductions of wind turbines are analyzed. Also possible implications and pitfalls when applying the experience curve methodology are assessed. Second, we present and discuss a new approach of establishing a global experience curve and thus a global progress ratio for the investment cost of wind farms. Results show that global progress ratios for wind farms may lie between 77% and 85% (with an average of 81%), which is significantly more optimistic than progress ratios applied in most current scenario studies and integrated assessment models. While the findings are based on a limited amount of data, they may indicate faster price reduction opportunities than so far assumed. With this global experience curve we aim to improve the reliability of describing the speed with which global costs of wind power may decline

  9. Strain Analysis of the de Mattia Test

    Directory of Open Access Journals (Sweden)

    Reiter M.

    2010-06-01

    Full Text Available The de Mattia test is a well-known, standardized and widely used method in the rubber industry for characterizing the fatigue behaviour of rubbers. Due to the visual observation and classification of the crack initiated, high data scatter were usually observed in these tests. To improve the quality of the de Mattia test and to support the applicability of the test method in modern design procedures, two novel experimental methods were proposed. Full-field strain analysis experiments using digital image correlation technique were performed and the local strains at the notch tip determined in the first. A global displacement vs. local strain calibration curves makes the design and conduction of strain based Wöhler curves possible. The crack initiation and crack growth is detected by an image analysis system and the crack growth rate was determined in the second method. To gain more insight into the fatigue behaviour of rubbers, these two novel methods were combined and can efficiently be used for characterizing the fatigue behaviour of rubbers.

  10. Effects of LWR coolant environments on fatigue design curves of carbon and low-alloy steels

    International Nuclear Information System (INIS)

    Chopra, O.K.; Shack, W.J.

    1998-03-01

    The ASME Boiler and Pressure Vessel Code provides rules for the construction of nuclear power plant components. Figures I-9.1 through I-9.6 of Appendix I to Section III of the code specify fatigue design curves for structural materials. While effects of reactor coolant environments are not explicitly addressed by the design curves, test data indicate that the Code fatigue curves may not always be adequate in coolant environments. This report summarizes work performed by Argonne National Laboratory on fatigue of carbon and low-alloy steels in light water reactor (LWR) environments. The existing fatigue S-N data have been evaluated to establish the effects of various material and loading variables such as steel type, dissolved oxygen level, strain range, strain rate, temperature, orientation, and sulfur content on the fatigue life of these steels. Statistical models have been developed for estimating the fatigue S-N curves as a function of material, loading, and environmental variables. The results have been used to estimate the probability of fatigue cracking of reactor components. The different methods for incorporating the effects of LWR coolant environments on the ASME Code fatigue design curves are presented

  11. Boundary layer for non-newtonian fluids on curved surfaces

    International Nuclear Information System (INIS)

    Stenger, N.

    1981-04-01

    By using the basic equation of fluid motion (conservation of mass and momentum) the boundary layer parameters for a Non-Newtonian, incompressible and laminar fluid flow, has been evaluated. As a test, the flat plate boundary layer is first analized and afterwards, a case with pressure gradient, allowing separation, is studied. In the case of curved surfaces, the problem is first developed in general and afterwards particularized to a circular cylinder. Finally suction and slip in the flow interface are examined. The power law model is used to represent the stress strain relationship in Non-Newtonian flow. By varying the fluid exponent one can then, have an idea of how the Non-Newtonian behavior of the flow influences the parameters of the boundary layer. Two equations, in an appropriate coordinate system have been obtained after an order of magnitude analysis of the terms in the equations of motion is performed. (Author) [pt

  12. Hamstring strain - aftercare

    Science.gov (United States)

    Pulled hamstring muscle; Sprain - hamstring ... There are 3 levels of hamstring strains: Grade 1 -- mild muscle strain or pull Grade 2 -- partial muscle tear Grade 3 -- complete muscle tear Recovery time depends ...

  13. Strain analysis of I-c(epsilon) characteristic of YBCO coated conductor measured by a Walters spring

    OpenAIRE

    Sugano, M; Choi, S; Miyazoe, A; Miyamatsu, K; Ando, T; Itoh, K; Kiyoshi, T; Wada, H; Selvamanickam, V

    2008-01-01

    lc-strain characteristic of YBCO coated conductor was measured using a Walters spring (WASP). In this technique, additional bending and thermal strains induced to the YBCO layer should be considered. In order to produce different initial bending strain to the YBCO layer, the conductor was wound around the springs with different diameters and in the different bending directions. The clear evidence was obtained that -strain curves using a WASP strongly depend on the initial bending strain state...

  14. The Effect of Grain Size on the Strain Hardening Behavior for Extruded ZK61 Magnesium Alloy

    Science.gov (United States)

    Zhang, Lixin; Zhang, Wencong; Chen, Wenzhen; Duan, Junpeng; Wang, Wenke; Wang, Erde

    2017-12-01

    The effects of grain size on the tensile and compressive strain hardening behaviors for extruded ZK61 alloys have been investigated by uniaxial tensile and compressive tests along the extrusion directions. Cylindrical tension and compression specimens of extruded ZK61 alloys with various sized grain were fabricated by annealing treatments. Tensile and compressive tests at ambient temperature were conducted at a strain rate of 0.5 × 10-3 s-1. The results indicate that both tensile strain hardening and compressive strain hardening of ZK61 alloys with different grain sizes have an athermal regime of dislocation accumulation in early deformation. The threshold stress value caused dynamic recovery is predominantly related to grain size in tensile strain hardening, but the threshold stress values for different grain sizes are almost identical in compressive strain hardening. There are obvious transition points on the tensile strain hardening curves which indicate the occurrence of dynamic recrystallization (DRX). The tensile strain hardening rate of the coarse-grained alloy obviously decreases faster than that of fine-grained alloys before DRX and the tensile strain hardening curves of different grain sizes basically tend to parallel after DRX. The compressive strain hardening rate of the fine-grained alloy obviously increases faster than that of coarse-grained alloy for twin-induced strain hardening, but compressive strain hardening curves also tend to parallel after twinning is exhausted.

  15. Stenting for curved lesions using a novel curved balloon: Preliminary experimental study.

    Science.gov (United States)

    Tomita, Hideshi; Higaki, Takashi; Kobayashi, Toshiki; Fujii, Takanari; Fujimoto, Kazuto

    2015-08-01

    Stenting may be a compelling approach to dilating curved lesions in congenital heart diseases. However, balloon-expandable stents, which are commonly used for congenital heart diseases, are usually deployed in a straight orientation. In this study, we evaluated the effect of stenting with a novel curved balloon considered to provide better conformability to the curved-angled lesion. In vitro experiments: A Palmaz Genesis(®) stent (Johnson & Johnson, Cordis Co, Bridgewater, NJ, USA) mounted on the Goku(®) curve (Tokai Medical Co. Nagoya, Japan) was dilated in vitro to observe directly the behavior of the stent and balloon assembly during expansion. Animal experiment: A short Express(®) Vascular SD (Boston Scientific Co, Marlborough, MA, USA) stent and a long Express(®) Vascular LD stent (Boston Scientific) mounted on the curved balloon were deployed in the curved vessel of a pig to observe the effect of stenting in vivo. In vitro experiments: Although the stent was dilated in a curved fashion, stent and balloon assembly also rotated conjointly during expansion of its curved portion. In the primary stenting of the short stent, the stent was dilated with rotation of the curved portion. The excised stent conformed to the curved vessel. As the long stent could not be negotiated across the mid-portion with the balloon in expansion when it started curving, the mid-portion of the stent failed to expand fully. Furthermore, the balloon, which became entangled with the stent strut, could not be retrieved even after complete deflation. This novel curved balloon catheter might be used for implantation of the short stent in a curved lesion; however, it should not be used for primary stenting of the long stent. Post-dilation to conform the stent to the angled vessel would be safer than primary stenting irrespective of stent length. Copyright © 2014 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

  16. Experimental determination of the yield stress curve of the scotch pine wood materials

    Science.gov (United States)

    Günay, Ezgi; Aygün, Cevdet; Kaya, Şükrü Tayfun

    2013-12-01

    Yield stress curve is determined for the pine wood specimens by conducting a series of tests. In this work, pinewood is modeled as a composite material with transversely isotropic fibers. Annual rings (wood grain) of the wood specimens are taken as the major fiber directions with which the strain gauge directions are aligned. For this purpose, three types of tests are arranged. These are tensile, compression and torsion loading tests. All of the tests are categorized with respect to fiber orientations and their corresponding loading conditions. Each test within these categories is conducted separately. Tensile and compression tests are conducted in accordance with standards of Turkish Standards Institution (TSE) whereas torsion tests are conducted in accordance with Standards Australia. Specimens are machined from woods of Scotch pine which is widely used in boat building industries and in other structural engineering applications. It is determined that this species behaves more flexibly than the others. Strain gauges are installed on the specimen surfaces in such a way that loading measurements are performed along directions either parallel or perpendicular to the fiber directions. During the test and analysis phase of yield stress curve, orientation of strain gauge directions with respect to fiber directions are taken into account. The diagrams of the normal stress vs. normal strain or the shear stress vs. shear strain are plotted for each test. In each plot, the yield stress is determined by selecting the point on the diagram, the tangent of which is having a slope of 5% less than the slope of the elastic portion of the diagram. The geometric locus of these selected points constitutes a single yield stress curve on σ1-σ2 principal plane. The resulting yield stress curve is plotted as an approximate ellipse which resembles Tsai-Hill failure criterion. The results attained in this work, compare well with the results which are readily available in the literature.

  17. Obturator internus muscle strains

    Directory of Open Access Journals (Sweden)

    Caoimhe Byrne, MB BCh, BAO

    2017-03-01

    Full Text Available We report 2 cases of obturator internus muscle strains. The injuries occurred in young male athletes involved in kicking sports. Case 1 details an acute obturator internus muscle strain with associated adductor longus strain. Case 2 details an overuse injury of the bilateral obturator internus muscles. In each case, magnetic resonance imaging played a crucial role in accurate diagnosis.

  18. Development of the curve of Spee.

    Science.gov (United States)

    Marshall, Steven D; Caspersen, Matthew; Hardinger, Rachel R; Franciscus, Robert G; Aquilino, Steven A; Southard, Thomas E

    2008-09-01

    Ferdinand Graf von Spee is credited with characterizing human occlusal curvature viewed in the sagittal plane. This naturally occurring phenomenon has clinical importance in orthodontics and restorative dentistry, yet we have little understanding of when, how, or why it develops. The purpose of this study was to expand our understanding by examining the development of the curve of Spee longitudinally in a sample of untreated subjects with normal occlusion from the deciduous dentition to adulthood. Records of 16 male and 17 female subjects from the Iowa Facial Growth Study were selected and examined. The depth of the curve of Spee was measured on their study models at 7 time points from ages 4 (deciduous dentition) to 26 (adult dentition) years. The Wilcoxon signed rank test was used to compare changes in the curve of Spee depth between time points. For each subject, the relative eruption of the mandibular teeth was measured from corresponding cephalometric radiographs, and its contribution to the developing curve of Spee was ascertained. In the deciduous dentition, the curve of Spee is minimal. At mean ages of 4.05 and 5.27 years, the average curve of Spee depths are 0.24 and 0.25 mm, respectively. With change to the transitional dentition, corresponding to the eruption of the mandibular permanent first molars and central incisors (mean age, 6.91 years), the curve of Spee depth increases significantly (P < 0.0001) to a mean maximum depth of 1.32 mm. The curve of Spee then remains essentially unchanged until eruption of the second molars (mean age, 12.38 years), when the depth increases (P < 0.0001) to a mean maximum depth of 2.17 mm. In the adolescent dentition (mean age, 16.21 years), the depth decreases slightly (P = 0.0009) to a mean maximum depth of 1.98 mm, and, in the adult dentition (mean age 26.98 years), the curve remains unchanged (P = 0.66), with a mean maximum depth of 2.02 mm. No significant differences in curve of Spee development were found between

  19. Modeling of X-ray rocking curves for layers after two-stage ion-implantation

    Directory of Open Access Journals (Sweden)

    O.I. Liubchenko

    2017-10-01

    Full Text Available In this work, we consider the approach for simulation of X-ray rocking curves inherent to InSb(111 crystals implanted with Be+ ions with various energies and doses. The method is based on the semi-kinematical theory of X-ray diffraction in the case of Bragg geometry. A fitting procedure that relies on the Hooke–Jeeves direct search algorithm was developed to determine the depth profiles of strain and structural disorders in the ion-modified layers. The thickness and maximum value of strain of ion-modified InSb(111 layers were determined. For implantation energies 66 and 80 keV, doses 25 and 50 µC, the thickness of the strained layer is about 500 nm with the maximum value of strain close to 0.1%. Additionally, an amorphous layer with significant thickness was found in the implantation region.

  20. Strain rate effect on the mechanical behavior of the anterior cruciate ligament-bone complex

    OpenAIRE

    Pioletti, Dominique P.; Rakotomanana, L. R.; Leyvraz, P. F.

    1999-01-01

    Traction tests were performed on the bovine anterior cruciate ligament-bone complex at seven strain rates (0.1, 1, 5, 10, 20, 30, 40%/s). Corresponding stress-strain curves showed that, for a given strain level, the stress increased with the augmentation of the strain rate. This phenomenon was important since the stress increased by a factor of three between the tests performed at the lowest and highest strain rates. The influence of the strain rate was quantified with a new variable called t...

  1. Mechanical Resonance Dispersion and Stress-Strain Behavior of Several Ionic Single Crystals

    National Research Council Canada - National Science Library

    Gotsky, Edward

    1965-01-01

    The tangent modulus of the compressive stress-strain curve, at any stress level up to the inflection point, agrees well with the low-frequency dynamic modulus determined at the corresponding stress...

  2. Investigation of strain heterogeneities by laser scanning extensometry in strain ageing materials: application to zirconium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Graff, S.; Forest, S.; Strudel, J.L. [Centre des Materiaux / UMR 7633, Ecole des Mines de Paris / CNRS, BP 87, 91003 Evry (France); Dierke, H.; Neuhauser, H. [Institut fur Physik der Kondensierten Materie, 38106 Braunschweig (Germany); Prioul, C. [MSSMAT, Ecole Centrale Paris, Grande Voie des Vignes, 92295 Chatenay-Malabry (France); Bechade, J.L. [SRMA, CEA Saclay, 91191 Gif sur Yvette (France)

    2005-07-01

    Laser scanning extensometry was used to detect and characterize propagating plastic instabilities such as the Luders bands at the millimeter scale. Spatio-temporal plastic heterogeneities are due to either static or dynamic strain ageing (SSA and DSA) phenomena. Regarding zirconium alloys, different type of heterogeneities were observed: their features strongly depended on mechanical test conditions. In one case, they appeared to be non propagating but preserved along the stress-strain curve and were associated with SSA effects such as stress peaks after relaxation periods or after unloading steps with waiting times. In other case, they appeared as non propagating but were not associated with SSA effects. (authors)

  3. Large strain detection of SRM composite shell based on fiber Bragg grating sensor

    Science.gov (United States)

    Zhang, Lei; Chang, Xinlong; Zhang, Youhong; Yang, Fan

    2017-12-01

    There may be more than 2% strain of carbon fiber composite material on solid rocket motor (SRM) in some extreme cases. A surface-bonded silica fiber Bragg grating (FBG) strain sensor coated by polymer is designed to detect the large strain of composite material. The strain transfer relation of the FBG large strain sensor is deduced, and the strain transfer mechanism is verified by finite element simulation. To calibrate the sensors, the tensile test is done by using the carbon fiber composite plate specimen attached to the designed strain sensor. The results show that the designed sensor can detect the strain more than 3%, the strain sensitivity is 0.0762 pm/μɛ, the resolution is 13.13μɛ, and the fitting degree of the wavelength-strain curve fitting function is 0.9988. The accuracy and linearity of the sensor can meet the engineering requirements.

  4. Computational modeling of dynamic mechanical properties of pure polycrystalline magnesium under high loading strain rates

    Directory of Open Access Journals (Sweden)

    Li Qizhen

    2015-01-01

    Full Text Available Computational simulations were performed to investigate the dynamic mechanical behavior of pure polycrystalline magnesium under different high loading strain rates with the values of 800, 1000, 2000, and 3600 s−1. The Johnson-Cook model was utilized in the simulations based on finite element modeling. The results showed that the simulations provided well-matched predictions of the material behavior such as the strain rate-time history, the stress-strain curve, and the temperature increase. Under high loading strain rates, the tested material experienced linear strain hardening at the early stage of plastic deformation, increased strain hardening at the intermediate plastic deformation region, and decreased strain hardening at the region before fracture. The strain hardening rates for the studied high loading strain rate cases do not vary much with the change of strain rates.

  5. Twists of genus three curves and their Jacobians

    NARCIS (Netherlands)

    Meagher, Stephen

    2008-01-01

    An algebraic curve is a curve defined over by polynomial equations with coefficients in a given field. This thesis treats problems which arise from genus three curves over finite fields. An important tool for treating such curves is the Jacobian variety of the curve. One problem is how many points

  6. Some issues using the master curve concept

    International Nuclear Information System (INIS)

    Viehrig, H.W.; Boehmert, J.

    2000-01-01

    The state-of-the-art structural integrity assessment of reactor pressure vessels (RPV) is based on the Reference Temperature Concept, initially proposed by the American Society of Mechanical Engineers (ASME). An experimentally ensured fracture toughness curve was constructed as the lower boundary of the available fracture toughness, K IC , of RPV steels. This conservative curve describing K IC as a function of temperature is used as a universal curve. For different RPV steels the curve is placed on the temperature axis over a reference temperature. In the initial state the nil-ductility-transition temperature (RT NDT ) is applied as reference temperature. The ductile to brittle transition temperature (DBTT) shift caused by the neutron irradiation is determined by Charpy V impact tests. The Charpy V DBTT shift is one of the results of the RPV surveillance programmes. The concept based on the ASME curve has the following disadvantages: - it is not consistent since it links fracture mechanical and technological parameters and - margins of safety and uncertainties cannot be quantified. (orig.)

  7. Brachistochrone curve of a fluid filled cylinder

    Science.gov (United States)

    Sarma, Srikanth; Raja, Sharan; Mahapatra, Pallab Sinha; Panchangnula, Mahesh

    2017-11-01

    The brachistochrone curve for a non-dissipative particle tries to maximize inertia of the particle but for a fluid filled cylinder, increasing inertia would amount to high dissipative losses. Hence the trade off between inertia and dissipation plays a vital role in the dynamics of a fluid filled cylinder. This trade off manifests itself in the form of an integro-differential equation governing the angular acceleration of the cylinder. Here, we compute the brachistochrone curve using optimal control principles and investigate the effect of the fore mentioned trade off on the deviation of the brachistochrone curve from that of a non-dissipative particle. Also, we investigate the effects of the non-dimensional parameters of the problem on the shape of the brachistochrone curve. We analyze the dissipation rate during the cylinder's motion and show that energy based arguments don't hold good for a fluid filled cylinder. We then analyze the stability of the time varying fluid flow in the cylinder and find an admissible region for the terminal point which would ensure the stability of the fluid flow as the cylinder rolls over the brachistochrone curve.

  8. Incorporating experience curves in appliance standards analysis

    International Nuclear Information System (INIS)

    Desroches, Louis-Benoit; Garbesi, Karina; Kantner, Colleen; Van Buskirk, Robert; Yang, Hung-Chia

    2013-01-01

    There exists considerable evidence that manufacturing costs and consumer prices of residential appliances have decreased in real terms over the last several decades. This phenomenon is generally attributable to manufacturing efficiency gained with cumulative experience producing a certain good, and is modeled by an empirical experience curve. The technical analyses conducted in support of U.S. energy conservation standards for residential appliances and commercial equipment have, until recently, assumed that manufacturing costs and retail prices remain constant during the projected 30-year analysis period. This assumption does not reflect real market price dynamics. Using price data from the Bureau of Labor Statistics, we present U.S. experience curves for room air conditioners, clothes dryers, central air conditioners, furnaces, and refrigerators and freezers. These experience curves were incorporated into recent energy conservation standards analyses for these products. Including experience curves increases the national consumer net present value of potential standard levels. In some cases a potential standard level exhibits a net benefit when considering experience, whereas without experience it exhibits a net cost. These results highlight the importance of modeling more representative market prices. - Highlights: ► Past appliance standards analyses have assumed constant equipment prices. ► There is considerable evidence of consistent real price declines. ► We incorporate experience curves for several large appliances into the analysis. ► The revised analyses demonstrate larger net present values of potential standards. ► The results imply that past standards analyses may have undervalued benefits.

  9. Applications for curved glass in buildings

    Directory of Open Access Journals (Sweden)

    Jürgen Neugebauer

    2015-05-01

    Full Text Available In the last years an increase of the number of building projects with built-in curved glass can be observed. The applications can principally be curved monolithic glass, laminated safety glass or insulated glass. This fact makes it absolute of interest to make more investigations in this field. The investigations can be focused on e.g. the process of the bending of the glass to bring it into a certain shape, or the very difficult topic of pre-stressing it. The state of the art of the production process of such glass shows some different ways to produce curved glass. The most used way is to bend the glass at a high temperature of more than 550° Celsius. Another kind of curved glass can be achieved in combination with the laminating process. With the cooling down at the end of the laminating process the interlayer becomes stiff enough to hold the shape by activated shear forces between the glass layers. Another possibility is to produce flat glass and bend it while mounting the glass. The question how to pre-stress curved glass is on the very first beginning of investigations. All these different processes are on the first view very easy but very difficult in the detail.

  10. Comparison of power curve monitoring methods

    Directory of Open Access Journals (Sweden)

    Cambron Philippe

    2017-01-01

    Full Text Available Performance monitoring is an important aspect of operating wind farms. This can be done through the power curve monitoring (PCM of wind turbines (WT. In the past years, important work has been conducted on PCM. Various methodologies have been proposed, each one with interesting results. However, it is difficult to compare these methods because they have been developed using their respective data sets. The objective of this actual work is to compare some of the proposed PCM methods using common data sets. The metric used to compare the PCM methods is the time needed to detect a change in the power curve. Two power curve models will be covered to establish the effect the model type has on the monitoring outcomes. Each model was tested with two control charts. Other methodologies and metrics proposed in the literature for power curve monitoring such as areas under the power curve and the use of statistical copulas have also been covered. Results demonstrate that model-based PCM methods are more reliable at the detecting a performance change than other methodologies and that the effectiveness of the control chart depends on the types of shift observed.

  11. Critical Factors for Inducing Curved Somatosensory Saccades

    Directory of Open Access Journals (Sweden)

    Tamami Nakano

    2011-10-01

    Full Text Available We are able to make a saccade toward a tactile stimuli to one hand, but trajectories of many saccades curved markedly when the arms were crossed (Groh & Sparks, 2006. However, it remains unknown why some curved and others did not. We therefore examined critical factors for inducing the curved somatosensory saccades. Participants made a saccade as soon as possible from a central fixation point toward a tactile stimulus delivered to one of the two hands, and switched between arms-crossed and arms-uncrossed postures every 6 trials. Trajectories were generally straight when the arms were uncrossed, but all participants made curved saccades when the arms were crossed (12–64%. We found that the probability of curved saccades depended critically on the onset latency: the probability was less than 5% when the latency was larger than 250 ms, but the probability increased up to 70–80% when the onset latency was 160 ms. This relationship was shared across participants. The results suggest that a touch in the arms-crossed posture was always mapped to the wrong hand in the initial phase up to 160 ms, and then remapped to the correct hand during the next 100 ms by some fundamental neural mechanisms shared across participants.

  12. A strain gauge

    DEFF Research Database (Denmark)

    2016-01-01

    The invention relates to a strain gauge of a carrier layer and a meandering measurement grid positioned on the carrier layer, wherein the strain gauge comprises two reinforcement members positioned on the carrier layer at opposite ends of the measurement grid in the axial direction....... The reinforcement members are each placed within a certain axial distance to the measurement grid with the axial distance being equal to or smaller than a factor times the grid spacing. The invention further relates to a multi-axial strain gauge such as a bi-axial strain gauge or a strain gauge rosette where each...... of the strain gauges comprises reinforcement members. The invention further relates to a method for manufacturing a strain gauge as mentioned above....

  13. Method for compression testing of composite materials at high strain rates

    Science.gov (United States)

    Daniel, I. M.; Labedz, R. H.

    1983-01-01

    A method is presented for testing composite materials in compression at strain rates up to approximately 500 per s. The method uses a thin ring specimen (4 in. in diameter, 1 in. wide, six-eight plies thick) loaded dynamically by an external pressure pulse applied explosively through a liquid. Strains in the specimen and in a steel calibration ring are recoorded with a digital processing oscilloscope. Results are plotted by an x-y plotter in the form of a dynamic stress-strain curve. Data analysis is based on a numerical solution of the equation of motion. A computer program is used which involves smoothing and approximation of the strain magnitude, strain rate, and strain acceleration. Dynamic stress-strain curves obtained for 0-deg and 90-deg specimens of two graphite/epoxy composites are presented.

  14. Interim fatigue design curves for carbon, low-alloy, and austenitic stainless steels in LWR environments

    International Nuclear Information System (INIS)

    Majumdar, S.; Chopra, O.K.; Shack, W.J.

    1993-01-01

    Both temperature and oxygen affect fatigue life; at the very low dissolved-oxygen levels in PWRs and BWRs with hydrogen water chemistry, environmental effects on fatigue life are modest at all temperatures (T) and strain rates. Between 0.1 and 0.2 ppM, the effect of dissolved-oxygen increases rapidly. In oxygenated environments, fatigue life depends strongly on strain rate and T. A fracture mechanics model is developed for predicting fatigue lives, and interim environmentally assisted cracking (EAC)-adjusted fatigue curves are proposed for carbon steels, low-alloy steels, and austenitic stainless steels

  15. Experimental simulation of closed timelike curves.

    Science.gov (United States)

    Ringbauer, Martin; Broome, Matthew A; Myers, Casey R; White, Andrew G; Ralph, Timothy C

    2014-06-19

    Closed timelike curves are among the most controversial features of modern physics. As legitimate solutions to Einstein's field equations, they allow for time travel, which instinctively seems paradoxical. However, in the quantum regime these paradoxes can be resolved, leaving closed timelike curves consistent with relativity. The study of these systems therefore provides valuable insight into nonlinearities and the emergence of causal structures in quantum mechanics--essential for any formulation of a quantum theory of gravity. Here we experimentally simulate the nonlinear behaviour of a qubit interacting unitarily with an older version of itself, addressing some of the fascinating effects that arise in systems traversing a closed timelike curve. These include perfect discrimination of non-orthogonal states and, most intriguingly, the ability to distinguish nominally equivalent ways of preparing pure quantum states. Finally, we examine the dependence of these effects on the initial qubit state, the form of the unitary interaction and the influence of decoherence.

  16. Asymmetry dependence of the nuclear caloric curve

    International Nuclear Information System (INIS)

    McIntosh, A.B.; Bonasera, A.; Cammarata, P.; Hagel, K.; Heilborn, L.; Kohley, Z.; Mabiala, J.; May, L.W.; Marini, P.; Raphelt, A.; Souliotis, G.A.; Wuenschel, S.; Zarrella, A.; Yennello, S.J.

    2013-01-01

    A basic feature of the nuclear equation of state is not yet understood: the dependence of the nuclear caloric curve on the neutron–proton asymmetry. Predictions of theoretical models differ on the magnitude and even the sign of this dependence. In this work, the nuclear caloric curve is examined for fully reconstructed quasi-projectiles around mass A=50. The caloric curve extracted with the momentum quadrupole fluctuation thermometer shows that the temperature varies linearly with quasi-projectile asymmetry (N−Z)/A . An increase in asymmetry of 0.15 units corresponds to a decrease in temperature on the order of 1 MeV. These results also highlight the importance of a full quasi-projectile reconstruction in the study of thermodynamic properties of hot nuclei

  17. The genus curve of the Abell clusters

    Science.gov (United States)

    Rhoads, James E.; Gott, J. Richard, III; Postman, Marc

    1994-01-01

    We study the topology of large-scale structure through a genus curve measurement of the recent Abell catalog redshift survey of Postman, Huchra, and Geller (1992). The structure is found to be spongelike near median density and to exhibit isolated superclusters and voids at high and low densities, respectively. The genus curve shows a slight shift toward 'meatball' topology, but remains consistent with the hypothesis of Gaussian random phase initial conditions. The amplitude of the genus curve corresponds to a power-law spectrum with index n = 0.21(sub -0.47 sup +0.43) on scales of 48/h Mpc or to a cold dark matter power spectrum with omega h = 0.36(sub -0.17 sup +0.46).

  18. Energy efficiency and load curve impacts

    International Nuclear Information System (INIS)

    Feilberg, Nicolai

    2002-01-01

    One of SINTEF Energy Research's European RTD projects is the two-year EFFLOCOM (Energy EFFiciency and LOad curve impacts of COMmercial development in competitive markets). This project will determine the end-user response of different market-related services offered in deregulated power markets. The project will investigate the possibility of influencing load curves by using different price signals and two-way communications via Internet. The partners are from Denmark. Finland, England, France and Norway. SINTEF Energy Research is in charge of the project management. During the project, the changes in load curves will he studied in the in the participating countries before and after deregulation. Specific issues are the use of ICT, time- and situation-dependent tariffs and smart-house technology. The project will consist of 5 work packages that will give recommendations about new methods, guidelines and tools to promote effective use of energy in the partner countries. The total budget is EUR 692 000. (author)

  19. Differential geometry of curves and surfaces

    CERN Document Server

    Banchoff, Thomas F

    2010-01-01

    Students and professors of an undergraduate course in differential geometry will appreciate the clear exposition and comprehensive exercises in this book that focuses on the geometric properties of curves and surfaces, one- and two-dimensional objects in Euclidean space. The problems generally relate to questions of local properties (the properties observed at a point on the curve or surface) or global properties (the properties of the object as a whole). Some of the more interesting theorems explore relationships between local and global properties. A special feature is the availability of accompanying online interactive java applets coordinated with each section. The applets allow students to investigate and manipulate curves and surfaces to develop intuition and to help analyze geometric phenomena.

  20. The many radial access learning curves.

    Science.gov (United States)

    Hillegass, William B

    2017-04-01

    The radial approach to endovascular procedures has a series of learning curves: diagnostic heart catheterization, low-risk settings and "straightforward" percutaneous coronary intervention, high-risk settings, and complex coronary intervention, and peripheral vascular angiography and intervention. For diagnostic and low-risk interventional procedures, incremental improvements in technical success and safety are observed in the initial 200 procedures for most operators compared to highly experienced operators. Formal didactic training and ongoing support/review from an experienced radial operator(s) may expedite surmounting the series of radial learning curves while maintaining optimal procedural success and safety. Advances in technology and understanding will require the most experienced radial operators to continually embrace their next learning curve. © 2017 Wiley Periodicals, Inc.

  1. Surface growth kinematics via local curve evolution

    KAUST Repository

    Moulton, Derek E.

    2012-11-18

    A mathematical framework is developed to model the kinematics of surface growth for objects that can be generated by evolving a curve in space, such as seashells and horns. Growth is dictated by a growth velocity vector field defined at every point on a generating curve. A local orthonormal basis is attached to each point of the generating curve and the velocity field is given in terms of the local coordinate directions, leading to a fully local and elegant mathematical structure. Several examples of increasing complexity are provided, and we demonstrate how biologically relevant structures such as logarithmic shells and horns emerge as analytical solutions of the kinematics equations with a small number of parameters that can be linked to the underlying growth process. Direct access to cell tracks and local orientation enables for connections to be made to the underlying growth process. © 2012 Springer-Verlag Berlin Heidelberg.

  2. Minimal families of curves on surfaces

    KAUST Repository

    Lubbes, Niels

    2014-11-01

    A minimal family of curves on an embedded surface is defined as a 1-dimensional family of rational curves of minimal degree, which cover the surface. We classify such minimal families using constructive methods. This allows us to compute the minimal families of a given surface.The classification of minimal families of curves can be reduced to the classification of minimal families which cover weak Del Pezzo surfaces. We classify the minimal families of weak Del Pezzo surfaces and present a table with the number of minimal families of each weak Del Pezzo surface up to Weyl equivalence.As an application of this classification we generalize some results of Schicho. We classify algebraic surfaces that carry a family of conics. We determine the minimal lexicographic degree for the parametrization of a surface that carries at least 2 minimal families. © 2014 Elsevier B.V.

  3. An investigation on vulnerability assessment of steel structures with thin steel shear wall through development of fragility curves

    Directory of Open Access Journals (Sweden)

    Mohsen Gerami

    2017-02-01

    Full Text Available Fragility curves play an important role in damage assessment of buildings. Probability of damage induction to the structure against seismic events can be investigated upon generation of afore mentioned curves. In current research 360 time history analyses have been carried out on structures of 3, 10 and 20 story height and subsequently fragility curves have been adopted. The curves are developed based on two indices of inter story drifts and equivalent strip axial strains of the shear wall. Time history analysis is carried out in Perform 3d considering 10 far field seismograms and 10 near fields. Analysis of low height structures revealed that they are more vulnerable in accelerations lower than 0.8 g in near field earthquakes because of higher mode effects. Upon the generated fragility curves it was observed that middle and high structures have more acceptable performance and lower damage levels compared to low height structures in both near and far field seismic hazards.

  4. POSSIBLE RECESSION CURVE APPLICATIONS FOR RETENTION EVALUATION

    Directory of Open Access Journals (Sweden)

    Daniel Liberacki

    2015-11-01

    Full Text Available The objective of the article was to present possible applications of recession flow curve in a small lowland watershed retention discharge size evaluation. The examined woodland micro catchment area of 0.52 sq km is located in Puszcza Zielonka in central Wielkopolska. The Hutka catchment is typically woody with high retention abilities. The catchment of the Hutka watercourse is forested in 89%, the other 11% is covered by swamps and wasteland. The predominant sites are fresh mixed coniferous forest (BMśw, fresh coniferous forest (Bśw and alder carr forest (Ol. Landscape in catchment is characterized by a large number of interior depressions, filled partly with rainwater or peatbogs, with poorly developed natural drainage. The watercourses do not exceed 1 km in length, the mean width is approx. 0.5 m, while mean depth ranges from 0.2 to 0.3 m. During hydrological research conducted in 1997/1998–1999/2000, 35 major (characteristic raised water stages were observed in Hutka after substantial precipitation. The recession curve dating from 18–24 September 2000 has the α and n rates nearest to average. Comparing the model curve and the curve created by observing watercourse flow, one can notice their resemblance and that they have similar ordinate values as well as shape. In the case of other recession curves, the maximum differences of ordinate values are also about 0.1–0.2 l/s/km2. The measuured α and n rates do not reveal any regularities. There are no significant statistical Horton model parameter (for recession flow curves dependencies between α and n and e.g. initial flows (Qo or the whole period of high water waves (Qp. Consequently, calculated relation between these parameters is only an approximation for the general evaluation of the retention discharge in the catchment area towards retention with flow function.

  5. From Curve Fitting to Machine Learning

    CERN Document Server

    Zielesny, Achim

    2011-01-01

    The analysis of experimental data is at heart of science from its beginnings. But it was the advent of digital computers that allowed the execution of highly non-linear and increasingly complex data analysis procedures - methods that were completely unfeasible before. Non-linear curve fitting, clustering and machine learning belong to these modern techniques which are a further step towards computational intelligence. The goal of this book is to provide an interactive and illustrative guide to these topics. It concentrates on the road from two dimensional curve fitting to multidimensional clus

  6. Computer Controlled Photometer/Planck Curve Experiment

    Science.gov (United States)

    Dupuy, David L.; Peters, Philip B.

    2001-11-01

    Developed as a demo in our course for computer control of laboratory experiments, this experiment had two goals: to attempt to measure the output of a tungsten bulb over a wide range of wavelengths, and to test the use of LabVIEW as a programming language for teaching experiment control. The brightness readings were corrected for instrumental effects and fitted with a Planck curve. The experiment involved digital input, digital output to a microstepper controller to move the filter wheel, and analog input. Results will be shown for the Planck curve and the LabVIEW program.

  7. Phonon dispersion curves for CsCN

    International Nuclear Information System (INIS)

    Gaur, N.K.; Singh, Preeti; Rini, E.G.; Galgale, Jyostna; Singh, R.K.

    2004-01-01

    The motivation for the present work was gained from the recent publication on phonon dispersion curves (PDCs) of CsCN from the neutron scattering technique. We have applied the extended three-body force shell model (ETSM) by incorporating the effect of coupling between the translation modes and the orientation of cyanide molecules for the description of phonon dispersion curves of CsCN between the temperatures 195 and 295 K. Our results on PDCs in symmetric direction are in good agreement with the experimental data measured with inelastic neutron scattering technique. (author)

  8. Angles between Curves in Metric Measure Spaces

    Directory of Open Access Journals (Sweden)

    Han Bang-Xian

    2017-09-01

    Full Text Available The goal of the paper is to study the angle between two curves in the framework of metric (and metric measure spaces. More precisely, we give a new notion of angle between two curves in a metric space. Such a notion has a natural interplay with optimal transportation and is particularly well suited for metric measure spaces satisfying the curvature-dimension condition. Indeed one of the main results is the validity of the cosine formula on RCD*(K, N metric measure spaces. As a consequence, the new introduced notions are compatible with the corresponding classical ones for Riemannian manifolds, Ricci limit spaces and Alexandrov spaces.

  9. Migration and the Wage-Settings Curve

    DEFF Research Database (Denmark)

    Brücker, Herbert; Jahn, Elke

    Germany on basis of a wage-setting curve. The wage-setting curve relies on the assumption that wages respond to a hange in the unemployment rate, albeit imperfectly. This allows one to derive the wage and employment effects of migration simultaneously in a general equilibrium framework. Using...... in the German labor force through immigration increases the aggregate unemployment rate by less than 0.1 percentage points and reduces average wages by 0.1 percent in the short run. While native workers benefit from increased wages and lower unemployment, foreign workers are adversely affected....

  10. Bound states in curved quantum waveguides

    International Nuclear Information System (INIS)

    Exner, P.; Seba, P.

    1987-01-01

    We study free quantum particle living on a curved planar strip Ω of a fixed width d with Dirichlet boundary conditions. It can serve as a model for electrons in thin films on a cylindrical-type substrate, or in a curved quantum wire. Assuming that the boundary of Ω is infinitely smooth and its curvature decays fast enough at infinity, we prove that a bound state with energy below the first transversal mode exists for all sufficiently small d. A lower bound on the critical width is obtained using the Birman-Schwinger technique. (orig.)

  11. Boiling curve in high quality flow boiling

    International Nuclear Information System (INIS)

    Shiralkar, B.S.; Hein, R.A.; Yadigaroglu, G.

    1980-01-01

    The post dry-out heat transfer regime of the flow boiling curve was investigated experimentally for high pressure water at high qualities. The test section was a short round tube located downstream of a hot patch created by a temperature controlled segment of tubing. Results from the experiment showed that the distance from the dryout point has a significant effect on the downstream temperatures and there was no unique boiling curve. The heat transfer coefficients measured sufficiently downstream of the dryout point could be correlated using the Heineman correlation for superheated steam, indicating that the droplet deposition effects could be neglected in this region

  12. Multivariate curve-fitting in GAUSS

    Science.gov (United States)

    Bunck, C.M.; Pendleton, G.W.

    1988-01-01

    Multivariate curve-fitting techniques for repeated measures have been developed and an interactive program has been written in GAUSS. The program implements not only the one-factor design described in Morrison (1967) but also includes pairwise comparisons of curves and rates, a two-factor design, and other options. Strategies for selecting the appropriate degree for the polynomial are provided. The methods and program are illustrated with data from studies of the effects of environmental contaminants on ducklings, nesting kestrels and quail.

  13. Light Curve Analysis of SAO23229

    Directory of Open Access Journals (Sweden)

    Ho-Il Kim

    1993-06-01

    Full Text Available We have made UBV light curves of a newly discovered eclipsing binary, SAO23229 at Sobaeksan Astronomy Observatory. We determined a minimum light time of HJD2448636.1170+/-0.0005 that is 3 minutes later than predicted time, and founda peculiar light variation at phase 0.75 that may not be secondary eclipse. Orbital period of SAO23229 would be 4.2 days rather than 2.1 days. Our analysis of the light curves shows that SAO23229 has a detached configuration consisting of two almost identical F type main sequence stars.

  14. A curved finite element for general thin shell structures

    International Nuclear Information System (INIS)

    Jones, R.F. Jr.

    1978-01-01

    This work describes the development of a curved quadrilateral shell finite element which demonstrates very good convergence properties. A general description is used in deriving the element so that it may be applied to any thin shell problem. The element is shown to be very efficient. It has a total of 36 degrees-of-freedom with 9 at each of the corners of the element. There are several distinct advantages that the element offers for practical applications. Most of the shell elements that have been presented in the past are limited to problems in which the coordinates on the shell surface are orthogonal. The element that is described in the paper is derived using a general description so that it may be applied to any thin shell problem including those in which the shell coordinates are not orthogonal. The degree-of-freedom at each of the four nodes are the three Cartesian displacements and their first derivatives with respect to the two surface coordinates. The imposition of boundary conditions is simplified since each of the degrees-of-freedom can be can be associated with a quantity which has a simple physical meaning. During the course of the derivation of the element, the strain displacement relationships are derived in a very simple manner consistent with Love's first approximation for thin shells. The derivation in the paper starts from basic principles and should help to shed some light on the proper form for the bending strain. Two primary contributions are presented in this work. The first is the presentation of a procedure for the development of a general quadrilateral shell element. The second is the simple derivation of the bending strain for the thin shells which apparently has not been presented previously. (Auth.)

  15. Analysis of characteristic performance curves in radiodiagnosis by an observer

    International Nuclear Information System (INIS)

    Kossovoj, A.L.

    1988-01-01

    Methods and ways of construction of performance characteristic curves (PX-curves) in roentgenology, their qualitative and quantitative estimation are described. Estimation of PX curves application for analysis of scintigraphic and sonographic images is presented

  16. Higher rank BN-theory for curves of genus 4

    OpenAIRE

    Lange, H.; Newstead, P. E.

    2015-01-01

    Higher rank Brill-Noether theory is completely known for curves of genus $\\leq 3$. In this paper, we investigate the theory for curves of genus 4. Some of our results apply to curves of arbitrary genus.

  17. Estimating reaction rate constants: comparison between traditional curve fitting and curve resolution

    NARCIS (Netherlands)

    Bijlsma, S.; Boelens, H. F. M.; Hoefsloot, H. C. J.; Smilde, A. K.

    2000-01-01

    A traditional curve fitting (TCF) algorithm is compared with a classical curve resolution (CCR) approach for estimating reaction rate constants from spectral data obtained in time of a chemical reaction. In the TCF algorithm, reaction rate constants an estimated from the absorbance versus time data

  18. Characterization of Elliptic Curve Traces under FR-reduction

    OpenAIRE

    Miyaji, Atsuko; Nakabayashi, Masaki; Takano, Shunzo

    2001-01-01

    Elliptic curve cryptosystems([19],[25]) are based on the elliptic curve discrete logarithm problem(ECDLP). If elliptic curve cryptosystems avoid FR-reduction([11],[17]) and anomalous elliptic curve over F_q ([34],[3],[36]), then with current knowledge we can construct elliptic curve cryptosystems over a smaller definition field. ECDLP has an interesting property that the security deeply depends on elliptic curve traces rather than definition fields, which does not occur in the case of the dis...

  19. Impact of the load curve on losses In the power supply network of the company

    Directory of Open Access Journals (Sweden)

    Я. Э. Шклярский

    2016-12-01

    Full Text Available In the recent years, the researchers and experts in the field of energetics often mention in their publications a need to reduce power transmission losses. Among different ways to accomplish this goal the method of the company load leveling stands out due to its simplicity, accessibility and efficiency. The paper proposes a new assessment factor for additional power losses in distribution network. It is known that dispersion of the load curve correlates with the amount of power losses, which is why the proposed factor is put in a position of dependency on the shape of the load curve of the company. It is demonstrated that the proposed factor can help to identify without any strain a need in technical measures for levelling the load curve of the company and to assess efficiency thereof.

  20. Some genus 3 curves with many points

    NARCIS (Netherlands)

    Auer, R; Top, J; Fieker, C; Kohel, DR

    2002-01-01

    We explain a naive approach towards the problem of finding genus 3 curves C over any given finite field F-q of odd characteristic, with a number of rational points close to the Hasse-Weil-Serre upper bound q+1+3[2rootq]. The method turns out to be successful at least in characteristic 3.

  1. Meromorphic connections on vector bundles over curves

    Indian Academy of Sciences (India)

    Descartes,. 67084 Strasbourg Cedex, France. *Correspond author. E-mail: indranil@math.tifr.res.in; heu@math.unistra.fr. MS received 17 July 2013; revised 20 October 2013. Abstract. We give a criterion for filtered vector bundles over curves to admit a ...

  2. Phonon dispersion curves of CsCN

    Indian Academy of Sciences (India)

    Abstract. The motivation for the present work was gained from the recent publication on phonon dispersion curves (PDCs) of CsCN from the neutron scattering technique. We have applied the extended three-body force shell model (ETSM) by incorporating the effect of coupling between the translation modes and the ...

  3. A Probabilistic Framework for Curve Evolution

    DEFF Research Database (Denmark)

    Dahl, Vedrana Andersen

    2017-01-01

    approach include ability to handle textured images, simple generalization to multiple regions, and efficiency in computation. We test our probabilistic framework in combination with parametric (snakes) and geometric (level-sets) curves. The experimental results on composed and natural images demonstrate...

  4. Replication and analysis of Ebbinghaus' forgetting curve

    NARCIS (Netherlands)

    Murre, J.M.J.; Dros, J.

    2015-01-01

    We present a successful replication of Ebbinghaus’ classic forgetting curve from 1880 based on the method of savings. One subject spent 70 hours learning lists and relearning them after 20 min, 1 hour, 9 hours, 1 day, 2 days, or 31 days. The results are similar to Ebbinghaus' original data. We

  5. Steady turbulent flow in curved rectangular channels

    NARCIS (Netherlands)

    De Vriend, H.J.

    1979-01-01

    After the study of fully developed and developing steady laminar flow in curved channels of shallow rectangular wet cross-section (see earlier reports in this series), steady turbulent flow in such channels is investigated as a next step towards a mathematical model of the flow in shallow river

  6. Developing laminar flow in curved rectangular channels

    NARCIS (Netherlands)

    De Vriend, H.J.

    1978-01-01

    As an intermediate step between earlier investigations on fully developed laminar flow in curved channels of shallow rectancular wet cross-section and the mathematical modeling of turbulent flow in river bends, a mathematical model of developing laminar flow in such channels is investigated. The

  7. Covariant quantizations in plane and curved spaces

    Energy Technology Data Exchange (ETDEWEB)

    Assirati, J.L.M. [University of Sao Paulo, Institute of Physics, Sao Paulo (Brazil); Gitman, D.M. [Tomsk State University, Department of Physics, Tomsk (Russian Federation); P.N. Lebedev Physical Institute, Moscow (Russian Federation); University of Sao Paulo, Institute of Physics, Sao Paulo (Brazil)

    2017-07-15

    We present covariant quantization rules for nonsingular finite-dimensional classical theories with flat and curved configuration spaces. In the beginning, we construct a family of covariant quantizations in flat spaces and Cartesian coordinates. This family is parametrized by a function ω(θ), θ element of (1,0), which describes an ambiguity of the quantization. We generalize this construction presenting covariant quantizations of theories with flat configuration spaces but already with arbitrary curvilinear coordinates. Then we construct a so-called minimal family of covariant quantizations for theories with curved configuration spaces. This family of quantizations is parametrized by the same function ω(θ). Finally, we describe a more wide family of covariant quantizations in curved spaces. This family is already parametrized by two functions, the previous one ω(θ) and by an additional function Θ(x,ξ). The above mentioned minimal family is a part at Θ = 1 of the wide family of quantizations. We study constructed quantizations in detail, proving their consistency and covariance. As a physical application, we consider a quantization of a non-relativistic particle moving in a curved space, discussing the problem of a quantum potential. Applying the covariant quantizations in flat spaces to an old problem of constructing quantum Hamiltonian in polar coordinates, we directly obtain a correct result. (orig.)

  8. Covariant quantizations in plane and curved spaces

    International Nuclear Information System (INIS)

    Assirati, J.L.M.; Gitman, D.M.

    2017-01-01

    We present covariant quantization rules for nonsingular finite-dimensional classical theories with flat and curved configuration spaces. In the beginning, we construct a family of covariant quantizations in flat spaces and Cartesian coordinates. This family is parametrized by a function ω(θ), θ element of (1,0), which describes an ambiguity of the quantization. We generalize this construction presenting covariant quantizations of theories with flat configuration spaces but already with arbitrary curvilinear coordinates. Then we construct a so-called minimal family of covariant quantizations for theories with curved configuration spaces. This family of quantizations is parametrized by the same function ω(θ). Finally, we describe a more wide family of covariant quantizations in curved spaces. This family is already parametrized by two functions, the previous one ω(θ) and by an additional function Θ(x,ξ). The above mentioned minimal family is a part at Θ = 1 of the wide family of quantizations. We study constructed quantizations in detail, proving their consistency and covariance. As a physical application, we consider a quantization of a non-relativistic particle moving in a curved space, discussing the problem of a quantum potential. Applying the covariant quantizations in flat spaces to an old problem of constructing quantum Hamiltonian in polar coordinates, we directly obtain a correct result. (orig.)

  9. Designing the Alluvial Riverbeds in Curved Paths

    Science.gov (United States)

    Macura, Viliam; Škrinár, Andrej; Štefunková, Zuzana; Muchová, Zlatica; Majorošová, Martina

    2017-10-01

    The paper presents the method of determining the shape of the riverbed in curves of the watercourse, which is based on the method of Ikeda (1975) developed for a slightly curved path in sandy riverbed. Regulated rivers have essentially slightly and smoothly curved paths; therefore, this methodology provides the appropriate basis for river restoration. Based on the research in the experimental reach of the Holeška Brook and several alluvial mountain streams the methodology was adjusted. The method also takes into account other important characteristics of bottom material - the shape and orientation of the particles, settling velocity and drag coefficients. Thus, the method is mainly meant for the natural sand-gravel material, which is heterogeneous and the particle shape of the bottom material is very different from spherical. The calculation of the river channel in the curved path provides the basis for the design of optimal habitat, but also for the design of foundations of armouring of the bankside of the channel. The input data is adapted to the conditions of design practice.

  10. Electronic properties of curved graphene sheets

    OpenAIRE

    Cortijo, Alberto; Vozmediano, Maria A. H.

    2006-01-01

    A model is proposed to study the electronic structure of slightly curved graphene sheets with an arbitrary number of pentagon-heptagon pairs and Stone-Wales defects based on a cosmological analogy. The disorder induced by curvature produces characteristic patterns in the local density of states that can be observed in scanning tunnel and transmission electron microscopy.

  11. A Mean Value Formula for Elliptic Curves

    Directory of Open Access Journals (Sweden)

    Rongquan Feng

    2014-01-01

    Full Text Available It is proved in this paper that, for any point on an elliptic curve, the mean value of x-coordinates of its n-division points is the same as its x-coordinate and that of y-coordinates of its n-division points is n times that of its y-coordinate.

  12. Bayesian Estimation of Item Response Curves.

    Science.gov (United States)

    Tsutakawa, Robert K.; Lin, Hsin Ying

    1986-01-01

    Item response curves for a set of binary responses are studied from a Bayesian viewpoint of estimating the item parameters. For the two-parameter logistic model with normally distributed ability, restricted bivariate beta priors are used to illustrate the computation of the posterior mode via the EM algorithm. (Author/LMO)

  13. Numerical analysis of thermoluminescence glow curves

    International Nuclear Information System (INIS)

    Gomez Ros, J. M.; Delgado, A.

    1989-01-01

    This report presents a method for the numerical analysis of complex thermoluminescence glow curves resolving the individual glow peak components. The method employs first order kinetics analytical expressions and is based In a Marquart-Levenberg minimization procedure. A simplified version of this method for thermoluminescence dosimetry (TLD) is also described and specifically developed to operate whit Lithium Fluoride TLD-100. (Author). 36 refs

  14. Light extraction block with curved surface

    Science.gov (United States)

    Levermore, Peter; Krall, Emory; Silvernail, Jeffrey; Rajan, Kamala; Brown, Julia J.

    2016-03-22

    Light extraction blocks, and OLED lighting panels using light extraction blocks, are described, in which the light extraction blocks include various curved shapes that provide improved light extraction properties compared to parallel emissive surface, and a thinner form factor and better light extraction than a hemisphere. Lighting systems described herein may include a light source with an OLED panel. A light extraction block with a three-dimensional light emitting surface may be optically coupled to the light source. The three-dimensional light emitting surface of the block may includes a substantially curved surface, with further characteristics related to the curvature of the surface at given points. A first radius of curvature corresponding to a maximum principal curvature k.sub.1 at a point p on the substantially curved surface may be greater than a maximum height of the light extraction block. A maximum height of the light extraction block may be less than 50% of a maximum width of the light extraction block. Surfaces with cross sections made up of line segments and inflection points may also be fit to approximated curves for calculating the radius of curvature.

  15. MulensModel: Microlensing light curves modeling

    Science.gov (United States)

    Poleski, Radoslaw; Yee, Jennifer

    2018-03-01

    MulensModel calculates light curves of microlensing events. Both single and binary lens events are modeled and various higher-order effects can be included: extended source (with limb-darkening), annual microlensing parallax, and satellite microlensing parallax. The code is object-oriented and written in Python3, and requires AstroPy (ascl:1304.002).

  16. Tempo curves considered harmful (part 2)

    NARCIS (Netherlands)

    Desain, P.; Honing, H.

    1991-01-01

    A column (the second of a series of three) constitutes an abridged and adapted version of Tempo curves considered harmful . M (an amateur mathematician) and P (a would-be psychologist) incorporated some generative models for expressive timing in their sequencer program. This proved partially

  17. Morphological modelling of strongly curved islands

    NARCIS (Netherlands)

    Roelvink, D.; Den Heijer, C.; Van Thiel De Vries, J.S.M.

    2013-01-01

    Land reclamations and island coasts often involve strongly curved shorelines, which are challenging to be properly modeled by numerical morphological models. Evaluation of the long term development of these types of coasts as well as their response to storm conditions requires proper representation

  18. Spherical images and inextensible curved folding

    Science.gov (United States)

    Seffen, Keith A.

    2018-02-01

    In their study, Duncan and Duncan [Proc. R. Soc. London A 383, 191 (1982), 10.1098/rspa.1982.0126] calculate the shape of an inextensible surface folded in two about a general curve. They find the analytical relationships between pairs of generators linked across the fold curve, the shape of the original path, and the fold angle variation along it. They present two special cases of generator layouts for which the fold angle is uniform or the folded curve remains planar, for simplifying practical folding in sheet-metal processes. We verify their special cases by a graphical treatment according to a method of Gauss. We replace the fold curve by a piecewise linear path, which connects vertices of intersecting pairs of hinge lines. Inspired by the d-cone analysis by Farmer and Calladine [Int. J. Mech. Sci. 47, 509 (2005), 10.1016/j.ijmecsci.2005.02.013], we construct the spherical images for developable folding of successive vertices: the operating conditions of the special cases in Duncan and Duncan are then revealed straightforwardly by the geometric relationships between the images. Our approach may be used to synthesize folding patterns for novel deployable and shape-changing surfaces without need of complex calculation.

  19. Electron conductance in curved quantum structures

    DEFF Research Database (Denmark)

    Willatzen, Morten; Gravesen, Jens

    2010-01-01

    A differential-geometry analysis is employed to investigate the transmission of electrons through a curved quantum-wire structure. Although the problem is a three-dimensional spatial problem, the Schrodinger equation can be separated into three general coordinates. Hence, the proposed method...

  20. Principal normal indicatrices of closed space curves

    DEFF Research Database (Denmark)

    Røgen, Peter

    1999-01-01

    A theorem due to J. Weiner, which is also proven by B. Solomon, implies that a principal normal indicatrix of a closed space curve with nonvanishing curvature has integrated geodesic curvature zero and contains no subarc with integrated geodesic curvature pi. We prove that the inverse problem alw...

  1. Yield stress independent column buckling curves

    DEFF Research Database (Denmark)

    Stan, Tudor‐Cristian; Jönsson, Jeppe

    2017-01-01

    Using GMNIA and shell finite element modelling of steel columns it is ascertained that the buckling curves for given imperfections and residual stresses are not only dependent on the relative slenderness ratio and the cross section shape but also on the magnitude of the yield stress. The influence...

  2. Theoretical Magnon Dispersion Curves for Gd

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker; Harmon, B. N.; Freeman, A. J.

    1975-01-01

    The magnon dispersion curve of Gd metal has been determined from first principles by use of augmented-plane-wave energy bands and wave functions. The exchange matrix elements I(k⃗, k⃗′) between the 4f electrons and the conduction electrons from the first six energy bands were calculated under...

  3. ATLAS detector records its first curved muon

    CERN Multimedia

    2007-01-01

    The barrel muon spectrometer of the ATLAS detector has acquired its first cosmic event in a magnetic field produced by the barrel toroid magnet. This was an important test of the chambers in their final configurations, and marked the first triggering and measurement of curved cosmic ray muons in ATLAS.

  4. Discrete groups, Mumford curves and Theta functions

    NARCIS (Netherlands)

    Put, Marius van der

    1992-01-01

    A discrete group Γ given over some complete non archimedean valued field defines a curve X. The theta functions for Γ provide an analytic construction for the Jacobian variety of X. A theory of theta functions is developed with the help of currents on trees and graphs and the cohomology for Γ. In

  5. Comparison and evaluation of mathematical lactation curve ...

    African Journals Online (AJOL)

    Using the General Linear Model procedure in SAS, the effect of herd, calving year, age at calving, season of production, age and days in milk were found to be significant on daily milk yield. The suitability of seven mathematical models (with three, four and five parameters) for describing the 305-day milk yield lactation curve ...

  6. Affine LIBOR Models with Multiple Curves

    DEFF Research Database (Denmark)

    Grbac, Zorana; Papapantoleon, Antonis; Schoenmakers, John

    2015-01-01

    We introduce a multiple curve framework that combines tractable dynamics and semianalytic pricing formulas with positive interest rates and basis spreads. Negative rates and positive spreads can also be accommodated in this framework. The dynamics of overnight indexed swap and LIBOR rates...

  7. Measuring Systematic Error with Curve Fits

    Science.gov (United States)

    Rupright, Mark E.

    2011-01-01

    Systematic errors are often unavoidable in the introductory physics laboratory. As has been demonstrated in many papers in this journal, such errors can present a fundamental problem for data analysis, particularly when comparing the data to a given model. In this paper I give three examples in which my students use popular curve-fitting software…

  8. Principal G-bundles on nodal curves

    Indian Academy of Sciences (India)

    Springer Verlag Heidelberg #4 2048 1996 Dec 15 10:16:45

    If Y is reducible these notions depend on parameters a = (a1,...,aI ). The study of G-bundles on Y is done by extending the notion of (generalized) parabolic vector bundles [U1] to generalized parabolic principal G-bundles (called GPGs in short) on the curve C and using the correspondence between them and principal ...

  9. Growth Curves for Girls with Turner Syndrome

    Directory of Open Access Journals (Sweden)

    Fabio Bertapelli

    2014-01-01

    Full Text Available The objective of this study was to review the growth curves for Turner syndrome, evaluate the methodological and statistical quality, and suggest potential growth curves for clinical practice guidelines. The search was carried out in the databases Medline and Embase. Of 1006 references identified, 15 were included. Studies constructed curves for weight, height, weight/height, body mass index, head circumference, height velocity, leg length, and sitting height. The sample ranged between 47 and 1,565 (total = 6,273 girls aged 0 to 24 y, born between 1950 and 2006. The number of measures ranged from 580 to 9,011 (total = 28,915. Most studies showed strengths such as sample size, exclusion of the use of growth hormone and androgen, and analysis of confounding variables. However, the growth curves were restricted to height, lack of information about selection bias, limited distributional properties, and smoothing aspects. In conclusion, we observe the need to construct an international growth reference for girls with Turner syndrome, in order to provide support for clinical practice guidelines.

  10. Principal normal indicatrices of closed space curves

    DEFF Research Database (Denmark)

    Røgen, Peter

    1997-01-01

    A theorem due to J. Weiner, which also is proven by B. Solomon, implies that a principal normal indicatrix of a closed space curve with non-vanishing curvature has integrated geodesic curvature zero and contains no sub arc with integrated geodesic curvature Pi. We prove that the inverse problem...

  11. Tropical count of curves on abelian varieties

    DEFF Research Database (Denmark)

    Halle, Lars Halvard; Rose, Simon Charles Florian

    2017-01-01

    We investigate the problem of counting tropical genus g curves ing-dimensional tropical abelian varieties. We do this by studyingmaps from principally polarized tropical abelian varieties into afixed abelian variety. For g = 2, 3, we prove that the tropical countmatches the count provided in [Göt98...

  12. Remote sensing used for power curves

    DEFF Research Database (Denmark)

    Wagner, Rozenn; Ejsing Jørgensen, Hans; Schmidt Paulsen, Uwe

    2008-01-01

    Power curve measurement for large wind turbines requires taking into account more parameters than only the wind speed at hub height. Based on results from aerodynamic simulations, an equivalent wind speed taking the wind shear into account was defined and found to reduce the power standard deviat...

  13. Tempo curves considered harmful (part 1)

    NARCIS (Netherlands)

    Desain, P.; Honing, H.

    1991-01-01

    A column (the first of a series of three) constitutes an abridged and adapted version of Tempo curves considered harmful . Two friends, an amateur mathematician (M) and a would-be psychologist (P), invited a retired pianist to do some experiments with their new sequencer program. As musical material

  14. Visualizing Nonlinear Narratives with Story Curves.

    Science.gov (United States)

    Kim, Nam Wook; Bach, Benjamin; Im, Hyejin; Schriber, Sasha; Gross, Markus; Pfister, Hanspeter

    2018-01-01

    In this paper, we present story curves, a visualization technique for exploring and communicating nonlinear narratives in movies. A nonlinear narrative is a storytelling device that portrays events of a story out of chronological order, e.g., in reverse order or going back and forth between past and future events. Many acclaimed movies employ unique narrative patterns which in turn have inspired other movies and contributed to the broader analysis of narrative patterns in movies. However, understanding and communicating nonlinear narratives is a difficult task due to complex temporal disruptions in the order of events as well as no explicit records specifying the actual temporal order of the underlying story. Story curves visualize the nonlinear narrative of a movie by showing the order in which events are told in the movie and comparing them to their actual chronological order, resulting in possibly meandering visual patterns in the curve. We also present Story Explorer, an interactive tool that visualizes a story curve together with complementary information such as characters and settings. Story Explorer further provides a script curation interface that allows users to specify the chronological order of events in movies. We used Story Explorer to analyze 10 popular nonlinear movies and describe the spectrum of narrative patterns that we discovered, including some novel patterns not previously described in the literature. Feedback from experts highlights potential use cases in screenplay writing and analysis, education and film production. A controlled user study shows that users with no expertise are able to understand visual patterns of nonlinear narratives using story curves.

  15. TELECOMMUNICATIONS INFRASTRUCTURE AND GDP /JIPP CURVE/

    Directory of Open Access Journals (Sweden)

    Mariana Kaneva

    2016-07-01

    Full Text Available The relationship between telecommunications infrastructure and economic activity is under discussion in many scientific papers. Most of the authors use for research and analysis the Jipp curve. A lot of doubts about the correctness of the Jipp curve appear in terms of applying econometric models. The aim of this study is a review of the Jipp curve, refining the possibility of its application in modern conditions. The methodology used in the study is based on dynamic econometric models, including tests for nonstationarity and tests for causality. The focus of this study is directed to methodological problems in measuring the local density types of telecommunication networks. This study offers a specific methodology for assessing the Jipp law, through VAR-approach and Granger causality tests. It is proved that mechanical substitution of momentary aggregated variables (such as the number of subscribers of a telecommunication network at the end of the year and periodically aggregated variables (such as GDP per capita in the Jipp�s curve is methodologically wrong. Researchers have to reconsider the relationship set in the Jipp�s curve by including additional variables that characterize the Telecommunications sector and the economic activity in a particular country within a specified time period. GDP per capita should not be regarded as a single factor for the local density of telecommunications infrastructure. New econometric models studying the relationship between the investments in telecommunications infrastructure and economic development may be not only linear regression models, but also other econometric models. New econometric models should be proposed after testing and validating with sound economic theory and econometric methodology.

  16. Trend analyses with river sediment rating curves

    Science.gov (United States)

    Warrick, Jonathan A.

    2015-01-01

    Sediment rating curves, which are fitted relationships between river discharge (Q) and suspended-sediment concentration (C), are commonly used to assess patterns and trends in river water quality. In many of these studies it is assumed that rating curves have a power-law form (i.e., C = aQb, where a and b are fitted parameters). Two fundamental questions about the utility of these techniques are assessed in this paper: (i) How well to the parameters, a and b, characterize trends in the data? (ii) Are trends in rating curves diagnostic of changes to river water or sediment discharge? As noted in previous research, the offset parameter, a, is not an independent variable for most rivers, but rather strongly dependent on b and Q. Here it is shown that a is a poor metric for trends in the vertical offset of a rating curve, and a new parameter, â, as determined by the discharge-normalized power function [C = â (Q/QGM)b], where QGM is the geometric mean of the Q values sampled, provides a better characterization of trends. However, these techniques must be applied carefully, because curvature in the relationship between log(Q) and log(C), which exists for many rivers, can produce false trends in â and b. Also, it is shown that trends in â and b are not uniquely diagnostic of river water or sediment supply conditions. For example, an increase in â can be caused by an increase in sediment supply, a decrease in water supply, or a combination of these conditions. Large changes in water and sediment supplies can occur without any change in the parameters, â and b. Thus, trend analyses using sediment rating curves must include additional assessments of the time-dependent rates and trends of river water, sediment concentrations, and sediment discharge.

  17. Uniaxial tension test on Rubber at constant true strain rate

    Directory of Open Access Journals (Sweden)

    Sourne H.L.

    2012-08-01

    Full Text Available Elastomers are widely used for damping parts in different industrial contexts because of their remarkable dissipation properties. Indeed, they can undergo severe mechanical loading conditions, i.e., high strain rates and large strains. Nevertheless, the mechanical response of these materials can vary from purely rubber-like to glassy depending on the strain rate undergone. Classically, uniaxial tension tests are made in order to find a relation between the stress and the strain in the material at various strain rates. However, even if the strain rate is searched to be constant, it is the nominal strain rate that is considered. Here we develop a test at constant true strain rate, i.e. the strain rate that is experienced by the material. In order to do such a test, the displacement imposed by the machine is an exponential function of time. This test has been performed with a high speed hydraulic machine for strain rates between 0.01/s and 100/s. A specific specimen has been designed, yielding a uniform strain field (and so a uniform stress field. Furthermore, an instrumented aluminum bar has been used to take into account dynamic effects in the measurement of the applied force. A high speed camera enables the determination of strain in the sample using point tracking technique. Using this method, the stress-strain curve of a rubber-like material during a loading-unloading cycle has been determined, up to a stretch ratio λ = 2.5. The influence of the true strain rate both on stiffness and on dissipation of the material is then discussed.

  18. Strain-engineered MOSFETs

    CERN Document Server

    Maiti, CK

    2012-01-01

    Currently strain engineering is the main technique used to enhance the performance of advanced silicon-based metal-oxide-semiconductor field-effect transistors (MOSFETs). Written from an engineering application standpoint, Strain-Engineered MOSFETs introduces promising strain techniques to fabricate strain-engineered MOSFETs and to methods to assess the applications of these techniques. The book provides the background and physical insight needed to understand new and future developments in the modeling and design of n- and p-MOSFETs at nanoscale. This book focuses on recent developments in st

  19. Quasi-Static Tensile Stress-Strain Curves. 1, 2024-T3510 Aluminum Alloy

    Science.gov (United States)

    1976-02-01

    FOR PURL*C RELEASE UNDER DOD DIRECTIVE 5200,20AND NO RESTRICTIONS ARE IMPOSED UPON ITS USE AND DISCLOSURE, DISTRIBUTION STATEMENT A APPROVED FOR PUBLIC...Dept of Engineering Sciencc Sciencies and Mechanics ATTN: Dr. U. Lindholm ATTN: Dr. C. A. Sciammarilla Dr. W. Baker Dr. L. Malvern 8500 Culebra Road Dr

  20. Stress-strain curves of steel and aluminium exposed to matural fires

    NARCIS (Netherlands)

    Maljaars, J.

    2010-01-01

    The temperature-dependent reduction factors on the yield stress in codes for steel structures, ky, are derived using a constant heating rate and a constant stress, where the influence of creep is implicitly taken into account. This paper considers the material properties of steel and aluminium on

  1. High strain rate tensile curves of hyperquenched Z03 CN18-10 stainless steel

    International Nuclear Information System (INIS)

    Vrillon, B.

    1978-01-01

    Tensile tests are presented at constant decreasing speeds, made at room temperature. This type of test can give a better evaluation of the structure behaviour in shock or burst loadings, because in that case the elongation speeds varies from high values to zero [fr

  2. Low Cycle Fatigue of Steel in Strain Controled Cyclic Bending

    Directory of Open Access Journals (Sweden)

    Kulesa Anna

    2016-03-01

    Full Text Available The paper presents a comparison of the fatigue life curves based on test of 15Mo3 steel under cyclic, pendulum bending and tension-compression. These studies were analyzed in terms of a large and small number of cycles where strain amplitude is dependent on the fatigue life. It has been shown that commonly used Manson-Coffin-Basquin model cannot be used for tests under cyclic bending due to the impossibility of separating elastic and plastic strains. For this purpose, some well-known models of Langer and Kandil and one new model of authors, where strain amplitude is dependent on the number of cycles, were proposed. Comparing the results of bending with tension-compression it was shown that for smaller strain amplitudes the fatigue life for both test methods were similar, for higher strain amplitudes fatigue life for bending tests was greater than for tension-compression.

  3. A Simplified Micromechanical Modeling Approach to Predict the Tensile Flow Curve Behavior of Dual-Phase Steels

    Science.gov (United States)

    Nanda, Tarun; Kumar, B. Ravi; Singh, Vishal

    2017-11-01

    Micromechanical modeling is used to predict material's tensile flow curve behavior based on microstructural characteristics. This research develops a simplified micromechanical modeling approach for predicting flow curve behavior of dual-phase steels. The existing literature reports on two broad approaches for determining tensile flow curve of these steels. The modeling approach developed in this work attempts to overcome specific limitations of the existing two approaches. This approach combines dislocation-based strain-hardening method with rule of mixtures. In the first step of modeling, `dislocation-based strain-hardening method' was employed to predict tensile behavior of individual phases of ferrite and martensite. In the second step, the individual flow curves were combined using `rule of mixtures,' to obtain the composite dual-phase flow behavior. To check accuracy of proposed model, four distinct dual-phase microstructures comprising of different ferrite grain size, martensite fraction, and carbon content in martensite were processed by annealing experiments. The true stress-strain curves for various microstructures were predicted with the newly developed micromechanical model. The results of micromechanical model matched closely with those of actual tensile tests. Thus, this micromechanical modeling approach can be used to predict and optimize the tensile flow behavior of dual-phase steels.

  4. Development of a viability standard curve for microencapsulated probiotic bacteria using confocal microscopy and image analysis software.

    Science.gov (United States)

    Moore, Sarah; Kailasapathy, Kasipathy; Phillips, Michael; Jones, Mark R

    2015-07-01

    Microencapsulation is proposed to protect probiotic strains from food processing procedures and to maintain probiotic viability. Little research has described the in situ viability of microencapsulated probiotics. This study successfully developed a real-time viability standard curve for microencapsulated bacteria using confocal microscopy, fluorescent dyes and image analysis software. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Effect of particle size and lattice strain on Debye–Waller factors of ...

    Indian Academy of Sciences (India)

    Administrator

    (1993), Gopi Krishna et al (2010). In the present work, the. Debye–Waller factor increases with milling time and lattice strain in a slightly nonlinear fashion. Figure 8 shows variation between lattice strain (ε) and. Debye–Waller factor (B). An extrapolation of the B vs ε curve to ε = 0 gives the value of Debye–Waller factors of.

  6. Numerical simulation for determination of limit strains of a cold rolled ...

    Indian Academy of Sciences (India)

    Limit strains or forming limit curve is one of the parameters that indicates the formability, especially the drawability of sheet metal for deep drawing applications. In this paper, the limit strains of Nimonic C-263 alloy is investigated and presented using an explicit finite element code LSDYNA 3D. The material properties and ...

  7. A strain gauge

    DEFF Research Database (Denmark)

    2017-01-01

    The invention relates to a strain gauge of a carrier layer and a meandering measurement grid (101) positioned on the carrier layer, wherein the measurement grid comprises a number of measurement grid sections placed side by side with gaps in between, and a number of end loops (106) interconnecting...... relates to a method for manufacturing a strain gauge as mentioned above....

  8. Approximate Implicitization of Parametric Curves Using Cubic Algebraic Splines

    Directory of Open Access Journals (Sweden)

    Xiaolei Zhang

    2009-01-01

    Full Text Available This paper presents an algorithm to solve the approximate implicitization of planar parametric curves using cubic algebraic splines. It applies piecewise cubic algebraic curves to give a global G2 continuity approximation to planar parametric curves. Approximation error on approximate implicitization of rational curves is given. Several examples are provided to prove that the proposed method is flexible and efficient.

  9. Evaluation of the water retention curve of Abidjan Quaternary aquifer ...

    African Journals Online (AJOL)

    Methods and Results: The water retention curve is difficult to measure in situ on large sites like this aquifer. Kovac's modified model to predict the water retention curve is tested. Predicted curves are compared with in situ measurements points. The results show that, overall, the model predicts well the water retention curves.

  10. Curvature Entropy for Curved Profile Generation

    Directory of Open Access Journals (Sweden)

    Koichiro Sato

    2012-03-01

    Full Text Available In a curved surface design, the overall shape features that emerge from combinations of shape elements are important. However, controlling the features of the overall shape in curved profiles is difficult using conventional microscopic shape information such as dimension. Herein two types of macroscopic shape information, curvature entropy and quadrature curvature entropy, quantitatively represent the features of the overall shape. The curvature entropy is calculated by the curvature distribution, and represents the complexity of a shape (one of the overall shape features. The quadrature curvature entropy is an improvement of the curvature entropy by introducing a Markov process to evaluate the continuity of a curvature and to approximate human cognition of the shape. Additionally, a shape generation method using a genetic algorithm as a calculator and the entropy as a shape generation index is presented. Finally, the applicability of the proposed method is demonstrated using the side view of an automobile as a design example.

  11. Cell Proliferation on Planar and Curved Substrates

    Science.gov (United States)

    Gaines, Michelle; Chang, Ya Wen; Cruz, Ricardo; Fragkopoulos, Alexandros; Garcia, Andres; Fernandez-Nieves, Alberto

    Aberrant epithelial collective cell growth is one of the major challenges to be addressed in order to treat diseases such as cancer and organ fibrosis. The conditions of the extracellular microenvironment, properties of the cells' cytoskeleton, and interfacial properties of the substratum (the surface in contact with epithelial cells) have a significant influence on the migratory behavior of epithelial cells, cell proliferation and migration. This work focuses on understanding the impact the substratum curvature has on cell behavior. We focus on cell proliferation first and study MDCK cells on both planar and curved hydrogel substrates. The curved hydrogels are based on polyacrylamide and have toroidal shape, with tube radius 200 um and an aspect ratio in the rage between 2 and 9. Proliferation is measured using the Click-it EDU assay (Invitrogen), which measures cells that are synthesizing DNA. Funding Source is Childrens Healthcare of Atlanta.

  12. Gauge field configurations in curved spacetimes (II)

    International Nuclear Information System (INIS)

    Boutaleb-Joutei, H.; Chakrabarti, A.; Comtet, A.

    1979-05-01

    One continues the study of gauge field configurations in curved spaces, using the formalism and results of a previous paper. A class of static, finite action, selfdual solutions of SU(2) gauge fields on a Euclidean section of de Sitter space is presented. The action depends on a continuous parameter. The spin connection solution is obtained as a particular case and a certain passage to the limiting case of a flat space is shown to reproduce the Euclidean Prasad-Sommerfield solution. The significance and possible interest of such solutions are discussed. The results are then generalized to a non-Einstein but conformally flat space, including de Sitter space as an Einstein limit. Next Baecklund type transformations are constructed starting from selfduality constraints for such curved spaces. These transformations are applied to the above mentioned solutions. The last two sections contain remarks on solutions with a background Robinson-Bertotti metric and on static, axially symmetric solutions respectively

  13. Inferring cardiac phase response curve in vivo

    Science.gov (United States)

    Pikovsky, Arkady; Kralemann, Bjoern; Fruehwirth, Matthias; Rosenblum, Michael; Kenner, Thomas; Schaefer, Jochen; Moser, Maximilian

    2014-03-01

    Characterizing properties of biological oscillators with phase response cirves (PRC) is one of main theoretical tools in neuroscience, cardio-respiratory physiology, and chronobiology. We present a technique that allows the extraction of the PRC from a non-invasive observation of a system consisting of two interacting oscillators, in this case heartbeat and respiration, in its natural environment and under free-running conditions. We use this method to obtain the phase coupling functions describing cardio-respiratory interactions and the phase response curve of 17 healthy humans. We show at which phase the cardiac beat is susceptible to respiratory drive and extract the respiratory-related component of heart rate variability. This non-invasive method of bivariate data analysis for the determination of phase response curves of coupled oscillators may find application in other biological and physical systems.

  14. Geometry of curves and surfaces with Maple

    CERN Document Server

    Rovenski, Vladimir

    2000-01-01

    This concise text on geometry with computer modeling presents some elementary methods for analytical modeling and visualization of curves and surfaces. The author systematically examines such powerful tools as 2-D and 3-D animation of geometric images, transformations, shadows, and colors, and then further studies more complex problems in differential geometry. Well-illustrated with more than 350 figures---reproducible using Maple programs in the book---the work is devoted to three main areas: curves, surfaces, and polyhedra. Pedagogical benefits can be found in the large number of Maple programs, some of which are analogous to C++ programs, including those for splines and fractals. To avoid tedious typing, readers will be able to download many of the programs from the Birkhauser web site. Aimed at a broad audience of students, instructors of mathematics, computer scientists, and engineers who have knowledge of analytical geometry, i.e., method of coordinates, this text will be an excellent classroom resource...

  15. Point- and curve-based geometric conflation

    KAUST Repository

    López-Vázquez, C.

    2013-01-01

    Geometric conflation is the process undertaken to modify the coordinates of features in dataset A in order to match corresponding ones in dataset B. The overwhelming majority of the literature considers the use of points as features to define the transformation. In this article we present a procedure to consider one-dimensional curves also, which are commonly available as Global Navigation Satellite System (GNSS) tracks, routes, coastlines, and so on, in order to define the estimate of the displacements to be applied to each object in A. The procedure involves three steps, including the partial matching of corresponding curves, the computation of some analytical expression, and the addition of a correction term in order to satisfy basic cartographic rules. A numerical example is presented. © 2013 Copyright Taylor and Francis Group, LLC.

  16. Ab-initio study of dynamical properties of two dimensional MoS2 under strain

    Directory of Open Access Journals (Sweden)

    Himadri Soni

    2015-10-01

    Full Text Available In this paper, we report the biaxial strain induced modifications in the phonon dispersion curves of monolayer MoS2 using first principles calculations in the framework of density functional perturbation theory. We have used the ultrasoft psedopotentials and the exchange correlation energies have been approximated by the local density approximation. There are significant changes in the phonon dispersion curves under strain. A systematic decrease in the optical phonon modes is observed with strain percentage. The longitudinal and transverse acoustic phonon modes of monolayer MoS2 show linear dependency for both without and with strain cases. However, the out of plane acoustic mode (ZA which behaves quadratically with wave vector k- turns linear under strain. We have also linked ripple in single layer (SL MoS2 by ZA mode with strain using shell elasticity theory. The strain induced softening of linear behaviour of ZA mode with strain indicates the absence of rippling under strain. At a very high strain there is a possibility of structural phase transition as the ZA mode at zone centre turns imaginary above 15% strain. Our results indicate a close relationship between the morphology and properties enabling the device tailoring and bandgap engineering in SL-MoS2 by manipulating the strain.

  17. String field theory in curved space

    International Nuclear Information System (INIS)

    Kikkawa, Keiji; Maeno, Masahiro; Sawada, Shiro

    1988-01-01

    The purely cubic action in the string field theory is shown to provide a set of equations of motion for background fields which agree to those obtained by the vanishing condition of β-functions in the non-linear sigma model. Using the sigma model as an auxiliary tool, a systematic method for solving the string field theory in curved space is proposed. (author)

  18. Growth curve models and statistical diagnostics

    CERN Document Server

    Pan, Jian-Xin

    2002-01-01

    Growth-curve models are generalized multivariate analysis-of-variance models. These models are especially useful for investigating growth problems on short times in economics, biology, medical research, and epidemiology. This book systematically introduces the theory of the GCM with particular emphasis on their multivariate statistical diagnostics, which are based mainly on recent developments made by the authors and their collaborators. The authors provide complete proofs of theorems as well as practical data sets and MATLAB code.

  19. Quantum field theory in curved spacetime

    International Nuclear Information System (INIS)

    Gibbons, G.W.

    1978-04-01

    The purpose of this article is to outline what the extension of such a treatment to curved space entails and to discuss what essentially new features arise when one takes into account the quantum mechanical nature of gravitating systems. I shall throughout assume a classical, unquantized gravitational field and confine the discussion to matter fields although similar techniques and ideas may be applied to 'gravitons' - that is linearized perturbations of the metric propagating on some fixed, unperturbed, background. (orig./WL) [de

  20. The Green functions in curved spacetime

    International Nuclear Information System (INIS)

    Buchbinder, I.L.; Kirillova, E.N.; Odinstov, S.D.

    1987-01-01

    The theory of a free scalar field with conformal coupling in curved spacetime with some special metrics is considered. The integral representations for the green function G-tilde in the form of integrals with Schwinger-De Witt kernel over contours in the complex plane of proper time are obtained. It is shown how the transitions from a unique Green function in Euclidean space to different Green functions in Minkowski space and vice versa can be carried out. (author)

  1. Twisted vector bundles on pointed nodal curves

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    is an element different from the identity and u is a geometric point of U fixed by γ, then the automorphism of the fiber ηu induced by γ is not trivial. 3. An essential action of a finite group on (η,U) is called tame, if the action of on. (U → S, i) is tame. DEFINITION 2.3. Let S be a k-scheme. Let C → S be an n-pointed nodal curve ...

  2. Bezier Curve Modeling for Neutrosophic Data Problem

    Directory of Open Access Journals (Sweden)

    Ferhat Tas

    2017-02-01

    Full Text Available Neutrosophic set concept is defined with membership, non-membership and indeterminacy degrees. This concept is the solution and representation of the problems with various fields. In this paper, a geometric model is introduced for Neutrosophic data problem for the first time. This model is based on neutrosophic sets and neutrosophic relations. Neutrosophic control points are defined according to these points, resulting in neutrosophic Bezier curves.

  3. Hydrogen technologies and the technology learning curve

    International Nuclear Information System (INIS)

    Rogner, H.-H.

    1998-01-01

    On their bumpy road to commercialization, hydrogen production, delivery and conversion technologies not only require dedicated research, development and demonstration efforts, but also protected niche markets and early adopters. While niche markets utilize the unique technological properties of hydrogen, adopters exhibit a willingness to pay a premium for hydrogen fueled energy services. The concept of the technology learning curve is applied to estimate the capital requirements associated with the commercialization process of several hydrogen technologies. (author)

  4. Stable curves and screens on fatgraphs

    DEFF Research Database (Denmark)

    Penner, Robert; McShane, Greg

    The mapping class group invariant ideal cell decomposition of the Teichmueller space of a punctured surface times an open simplex has been used in a number of computations. This paper answers a question about the asymptotics of this decomposition, namely, in a given cell of the decomposition, whi...... curves can be short? Screens are a new combinatorial structure which provide an answer to this question. The heart of the calculation here involves Ptolemy transformations and the triangle inequalities on lambda lengths....

  5. Feynman propagator in curved space-time

    International Nuclear Information System (INIS)

    Candelas, P.; Raine, D.J.

    1977-01-01

    The Wick rotation is generalized in a covariant manner so as to apply to curved manifolds in a way that is independent of the analytic properties of the manifold. This enables us to show that various methods for defining a Feynman propagator to be found in the literature are equivalent where they are applicable. We are also able to discuss the relation between certain regularization methods that have been employed

  6. Numerical Characterization of Piezoceramics Using Resonance Curves

    Directory of Open Access Journals (Sweden)

    Nicolás Pérez

    2016-01-01

    Full Text Available Piezoelectric materials characterization is a challenging problem involving physical concepts, electrical and mechanical measurements and numerical optimization techniques. Piezoelectric ceramics such as Lead Zirconate Titanate (PZT belong to the 6 mm symmetry class, which requires five elastic, three piezoelectric and two dielectric constants to fully represent the material properties. If losses are considered, the material properties can be represented by complex numbers. In this case, 20 independent material constants are required to obtain the full model. Several numerical methods have been used to adjust the theoretical models to the experimental results. The continuous improvement of the computer processing ability has allowed the use of a specific numerical method, the Finite Element Method (FEM, to iteratively solve the problem of finding the piezoelectric constants. This review presents the recent advances in the numerical characterization of 6 mm piezoelectric materials from experimental electrical impedance curves. The basic strategy consists in measuring the electrical impedance curve of a piezoelectric disk, and then combining the Finite Element Method with an iterative algorithm to find a set of material properties that minimizes the difference between the numerical impedance curve and the experimental one. Different methods to validate the results are also discussed. Examples of characterization of some common piezoelectric ceramics are presented to show the practical application of the described methods.

  7. Detection of flaws below curved surfaces

    International Nuclear Information System (INIS)

    Elsley, R.K.; Addison, R.C.; Graham, L.J.

    1983-01-01

    A measurement model has been developed to describe ultrasonic measurements made with circular piston transducers in parts with flat or cylindrically curved surfaces. The model includes noise terms to describe electrical noise, scatterer noise and echo noise as well as effects of attenuation, diffraction and Fresnel loss. An experimental procedure for calibrating the noise terms of the model was developed. Experimental measurements were made on a set of known flaws located beneath a cylindrically curved surface. The model was verified by using it to correct the experimental measurements to obtain the absolute scattering amplitude of the flaws. For longitudinal wave propagation within the part, the derived scattering amplitudes were consistent with predictions at internal angles of less than 30 0 . At larger angles, focusing and aberrations caused a lack of agreement; the model needs further refinement in this case. For shear waves, it was found that the frequency for optimum flaw detection in the presence of material noise is lower than that for longitudinal waves; lower frequency measurements are currently in progress. The measurement model was then used to make preliminary predictions of the best experimental measurement technique for the detection of cracks located under cylindrically curved surfaces

  8. Learning curve for radical retropubic prostatectomy

    Directory of Open Access Journals (Sweden)

    Fernando J. A. Saito

    2011-02-01

    Full Text Available PURPOSE: The learning curve is a period in which the surgical procedure is performed with difficulty and slowness, leading to a higher risk of complications and reduced effectiveness due the surgeon's inexperience. We sought to analyze the residents' learning curve for open radical prostatectomy (RP in a training program. MATERIALS AND METHODS: We conducted a prospective study from June 2006 to January 2008 in the academic environment of the University of São Paulo. Five residents operated on 184 patients during a four-month rotation in the urologic oncology division, mentored by the same physician assistants. We performed sequential analyses according to the number of surgeries, as follows: = 10, 11 to 19, 20 to 28, and = 29. RESULTS: The residents performed an average of 37 RP each. The average psa was 9.3 ng/mL and clinical stage T1c in 71% of the patients. The pathological stage was pT2 (73%, pT3 (23%, pT4 (4%, and 46% of the patients had a Gleason score 7 or higher. In all surgeries, the average operative time and estimated blood loss was 140 minutes and 488 mL. Overall, 7.2% of patients required blood transfusion, and 23% had positive surgical margins. CONCLUSION: During the initial RP learning curve, we found a significant reduction in the operative time; blood transfusion during the procedures and positive surgical margin rate were stable in our series.

  9. Breakthrough curve moments scaling in hyporheic exchange

    Science.gov (United States)

    Bellin, A.; Tonina, D.; Marzadri, A.

    2015-02-01

    The interaction between stream flow and bed forms creates an uneven distribution of near-bed energy heads, which is the driving force of hyporheic exchange. Owing to the large disparity of advection characteristic times in the stream and within the hyporheic zone, solute mass exchange is often modeled by considering the latter as an immobile region. In a recent contribution Gónzalez-Pinzón et al. (2013) showed that existing models employing this hypothesis are structurally inconsistent with the scaling revealed by the analysis of 384 breakthrough curves collected in 44 streams across five continents. Motivated by this result, we analyze the scaling characteristics of a model that we recently developed by combining the analytical solution of the advective flow within the hyporheic zone with a Lagrangian solute transport model. Results show that similarly to the experimental data our model predicts breakthrough curves with a constant skewness, irrespective of the stream size, and that the scaling of the first three moments observed by Gónzalez-Pinzón et al. (2013) is also respected. Moreover, we propose regression curves that relate the first three moments of the residence time distribution with the alternate bar dimensionless depth (YBM*), a quantity that is easily measurable in the field. The connection between BTC moments and YBM* opens new possibilities for modeling transport processes at the catchment scale.

  10. Numerical Characterization of Piezoceramics Using Resonance Curves

    Science.gov (United States)

    Pérez, Nicolás; Buiochi, Flávio; Brizzotti Andrade, Marco Aurélio; Adamowski, Julio Cezar

    2016-01-01

    Piezoelectric materials characterization is a challenging problem involving physical concepts, electrical and mechanical measurements and numerical optimization techniques. Piezoelectric ceramics such as Lead Zirconate Titanate (PZT) belong to the 6 mm symmetry class, which requires five elastic, three piezoelectric and two dielectric constants to fully represent the material properties. If losses are considered, the material properties can be represented by complex numbers. In this case, 20 independent material constants are required to obtain the full model. Several numerical methods have been used to adjust the theoretical models to the experimental results. The continuous improvement of the computer processing ability has allowed the use of a specific numerical method, the Finite Element Method (FEM), to iteratively solve the problem of finding the piezoelectric constants. This review presents the recent advances in the numerical characterization of 6 mm piezoelectric materials from experimental electrical impedance curves. The basic strategy consists in measuring the electrical impedance curve of a piezoelectric disk, and then combining the Finite Element Method with an iterative algorithm to find a set of material properties that minimizes the difference between the numerical impedance curve and the experimental one. Different methods to validate the results are also discussed. Examples of characterization of some common piezoelectric ceramics are presented to show the practical application of the described methods. PMID:28787875

  11. Open Timelike Curves Violate Heisenberg's Uncertainty Principle

    Science.gov (United States)

    Pienaar, J. L.; Ralph, T. C.; Myers, C. R.

    2013-02-01

    Toy models for quantum evolution in the presence of closed timelike curves have gained attention in the recent literature due to the strange effects they predict. The circuits that give rise to these effects appear quite abstract and contrived, as they require nontrivial interactions between the future and past that lead to infinitely recursive equations. We consider the special case in which there is no interaction inside the closed timelike curve, referred to as an open timelike curve (OTC), for which the only local effect is to increase the time elapsed by a clock carried by the system. Remarkably, circuits with access to OTCs are shown to violate Heisenberg’s uncertainty principle, allowing perfect state discrimination and perfect cloning of coherent states. The model is extended to wave packets and smoothly recovers standard quantum mechanics in an appropriate physical limit. The analogy with general relativistic time dilation suggests that OTCs provide a novel alternative to existing proposals for the behavior of quantum systems under gravity.

  12. Describing the learning curve for bulbar urethroplasty.

    Science.gov (United States)

    Spilotros, Marco; Malde, Sachin; Greenwell, Tamsin J

    2017-12-01

    Learning curves have been described for a number of urological procedures including radical prostatectomy and laparoscopic nephrectomy but rarely for urethroplasty. We describe the learning curve for bulbar urethroplasty in a single surgeon series. A retrospective case note review was performed of 91 consecutive men median age 32 years (range, 15-66 years) having bulbar urethroplasty performed by a single surgeon. Data was collected on type of urethroplasty, restricture rate (as defined by urethrogram and/or flow rate) and duration of follow up. The restricture rates were compared by quartiles and statistical analysis was by ¦Ö 2 between the first and fourth quartiles. The 91 men had 42 dorsal onlay buccal mucosal graft (Dorsal BMG), 20 BMG augmented bulbobulbar anastomotic (Augmented Rooftop) and 29 bulbobulbar anastomotic (BBA) urethroplasties performed. Median follow up was 39 months for the first quartile, 42 months for the second, 36 months for the third, and 35 months for the fourth. The restricture rate was 17% in the first quartile, 8.7% in the second and third quartiles and 4.5% in the fourth quartile. There were no restrictures noted after 24 months. There were 4 restrictures in the first quartile and 1 restricture in the fourth quartile (¦Ö 2 Plearning curve for bulbar urethroplasty with a reduced restricture rate each quartile and it may take as many as 90 cases to reach optimum restricture rates.

  13. Open timelike curves violate Heisenberg's uncertainty principle.

    Science.gov (United States)

    Pienaar, J L; Ralph, T C; Myers, C R

    2013-02-08

    Toy models for quantum evolution in the presence of closed timelike curves have gained attention in the recent literature due to the strange effects they predict. The circuits that give rise to these effects appear quite abstract and contrived, as they require nontrivial interactions between the future and past that lead to infinitely recursive equations. We consider the special case in which there is no interaction inside the closed timelike curve, referred to as an open timelike curve (OTC), for which the only local effect is to increase the time elapsed by a clock carried by the system. Remarkably, circuits with access to OTCs are shown to violate Heisenberg's uncertainty principle, allowing perfect state discrimination and perfect cloning of coherent states. The model is extended to wave packets and smoothly recovers standard quantum mechanics in an appropriate physical limit. The analogy with general relativistic time dilation suggests that OTCs provide a novel alternative to existing proposals for the behavior of quantum systems under gravity.

  14. Incorporating Experience Curves in Appliance Standards Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Garbesi, Karina; Chan, Peter; Greenblatt, Jeffery; Kantner, Colleen; Lekov, Alex; Meyers, Stephen; Rosenquist, Gregory; Buskirk, Robert Van; Yang, Hung-Chia; Desroches, Louis-Benoit

    2011-10-31

    The technical analyses in support of U.S. energy conservation standards for residential appliances and commercial equipment have typically assumed that manufacturing costs and retail prices remain constant during the projected 30-year analysis period. There is, however, considerable evidence that this assumption does not reflect real market prices. Costs and prices generally fall in relation to cumulative production, a phenomenon known as experience and modeled by a fairly robust empirical experience curve. Using price data from the Bureau of Labor Statistics, and shipment data obtained as part of the standards analysis process, we present U.S. experience curves for room air conditioners, clothes dryers, central air conditioners, furnaces, and refrigerators and freezers. These allow us to develop more representative appliance price projections than the assumption-based approach of constant prices. These experience curves were incorporated into recent energy conservation standards for these products. The impact on the national modeling can be significant, often increasing the net present value of potential standard levels in the analysis. In some cases a previously cost-negative potential standard level demonstrates a benefit when incorporating experience. These results imply that past energy conservation standards analyses may have undervalued the economic benefits of potential standard levels.

  15. Prospects for PV: a learning curve analysis

    International Nuclear Information System (INIS)

    Zwaan, Bob van der; Rabi, A.

    2003-01-01

    This article gives an overview of the current state-of-the-art of photovoltaic electricity technology, and addresses its potential for cost reductions over the first few decades of the 21st century. Current PV production cost ranges are presented, both in terms of capacity installation and electricity generation, of single crystalline silicon, multi-crystalline silicon, amorphous silicon and other thin film technologies. Possible decreases of these costs are assessed, as expected according to the learning-curve methodology. We also estimate how much PV could gain if external costs (due to environmental and health damage) of energy were internalised, for example by an energy tax. Our conclusions are that, (1) mainly due its high costs, PV electricity is unlikely to play a major role in global energy supply and carbon emissions abatement before 2020, (2) extrapolating learning curves observed in the past, one can expect its costs to decrease significantly over the coming years, so that a considerable PV electricity share world-wide could materialise after 2020, (3) niche-market applications, e.g. using stand-alone systems in remote areas, are crucial for continuing 'the ride along the learning curve', (4) damage costs of conventional (fossil) power sources are considerable, and their internalisation would improve the competitiveness of PV, although probably not enough to close the current cost gap. (author)

  16. Dynamic Crack Curving - A Photoelastic Evaluation.

    Science.gov (United States)

    1981-10-01

    the minimum strain energy density. Theocaris and Andrianopoulos [14], recently modified the S-theory by designating its mean value, T, the critical...moderate values of r0 irrespective of the sign of K1I/KI. This result re-emphasizes the importance of the non-singular stress termo x , which, when

  17. Investigating the relationship between unsaturated hydraulic conductivity curve and confined compression curve

    Science.gov (United States)

    Bayat, Hossein; Sedaghat, Azadeh; Safari Sinegani, Ali Akbar; Gregory, Andrew S.

    2015-03-01

    This study was conducted to estimate the soil unsaturated hydraulic conductivity through the van Genuchten model using easy to measure soil properties by regression and artificial neural networks methods. In this study, 148 soil samples were taken from five provinces of Iran. Basic soil properties (clay, silt/sand and bulk density) and other soil properties were measured. Soil water retention curve was measured to obtain the unsaturated hydraulic conductivity curve using the van Genuchten-Mualem model. Confined compression curve was measured and the modified model of van Genuchten was fitted on its data. Two-thirds and one-third of the data were used for the training and testing steps, respectively. Confined compression curve parameters and other soil properties were used as predictors to estimate unsaturated hydraulic conductivity curve. Pedotransfer functions (PTFs) were developed in two separate parts: in 5 and 6 PTFs basic soil properties were or were not used as predictors, respectively. The artificial neural networks (ANNs) performed better than the regression methods. Among the ANN-developed PTFs which have not used basic soil properties as predictors, PTFa3, with the inputs of the parameters of confined compression curve (n∗, α∗ and e0), performed better than the others. Also, among the ANN-developed PTFs that used basic soil properties as predictors along with the other input variables, PTFb5 that used the σmc (stress at the maximum curvature) and σi (stress at the inflection point) as inputs along with basic soil properties, performed better than the other PTFs. The results showed a successful prediction of the hydraulic conductivity curve using confined compression curve.

  18. Unsteady Aerodynamic Force Sensing from Measured Strain

    Science.gov (United States)

    Pak, Chan-Gi

    2016-01-01

    A simple approach for computing unsteady aerodynamic forces from simulated measured strain data is proposed in this study. First, the deflection and slope of the structure are computed from the unsteady strain using the two-step approach. Velocities and accelerations of the structure are computed using the autoregressive moving average model, on-line parameter estimator, low-pass filter, and a least-squares curve fitting method together with analytical derivatives with respect to time. Finally, aerodynamic forces over the wing are computed using modal aerodynamic influence coefficient matrices, a rational function approximation, and a time-marching algorithm. A cantilevered rectangular wing built and tested at the NASA Langley Research Center (Hampton, Virginia, USA) in 1959 is used to validate the simple approach. Unsteady aerodynamic forces as well as wing deflections, velocities, accelerations, and strains are computed using the CFL3D computational fluid dynamics (CFD) code and an MSC/NASTRAN code (MSC Software Corporation, Newport Beach, California, USA), and these CFL3D-based results are assumed as measured quantities. Based on the measured strains, wing deflections, velocities, accelerations, and aerodynamic forces are computed using the proposed approach. These computed deflections, velocities, accelerations, and unsteady aerodynamic forces are compared with the CFL3D/NASTRAN-based results. In general, computed aerodynamic forces based on the lifting surface theory in subsonic speeds are in good agreement with the target aerodynamic forces generated using CFL3D code with the Euler equation. Excellent aeroelastic responses are obtained even with unsteady strain data under the signal to noise ratio of -9.8dB. The deflections, velocities, and accelerations at each sensor location are independent of structural and aerodynamic models. Therefore, the distributed strain data together with the current proposed approaches can be used as distributed deflection

  19. Hypothesized, Directly-Coded Curve Shapes in Growth Curve Analysis: An Example

    Directory of Open Access Journals (Sweden)

    Patricia M. Herman

    2013-02-01

    Full Text Available Growth curve analysis provides important informational benefits regarding intervention outcomes over time. Rarely, however, should outcome trajectories be assumed to be linear. Instead, both the shape and the slope of the growth curve can be estimated. Non-linear growth curves are usually modeled by including either higher-order time variables or orthogonal polynomial contrast codes. Each has limitations (multicollinearity with the first, a lack of coefficient interpretability with the second, and a loss of degrees of freedom with both and neither encourages direct testing of alternative hypothesized curve shapes. Especially in studies with relatively small samples it is likely to be useful to preserve as much information as possible at the individual level. This article presents a step-by-step example of the use and testing of hypothesized curve shapes in the estimation of growth curves using hierarchical linear modeling for a small intervention study. DOI: 10.2458/azu_jmmss.v3i2.16476

  20. NOISY DISPERSION CURVE PICKING (NDCP): a Matlab friendly suite package for fully control dispersion curve picking

    Science.gov (United States)

    Granados, I.; Calo, M.; Ramos, V.

    2017-12-01

    We developed a Matlab suite package (NDCP, Noisy Dispersion Curve Picking) that allows a full control over parameters to identify correctly group velocity dispersion curves in two types of datasets: correlograms between two stations or surface wave records from earthquakes. Using the frequency-time analysis (FTAN), the procedure to obtain the dispersion curves from records with a high noise level becomes difficult, and sometimes, the picked curve result in a misinterpreted character. For correlogram functions, obtained with cross-correlation of noise records or earthquake's coda, a non-homogeneous noise sources distribution yield to a non-symmetric Green's function (GF); to retrieve the complete information contained in there, NDCP allows to pick the dispersion curve in the time domain both in the causal and non-causal part of the GF. Then the picked dispersion curve is displayed on the FTAN diagram to in order to check if it matches with the maximum of the signal energy avoiding confusion with overtones or spike of noise. To illustrate how NDCP performs, we show exemple using: i) local correlograms functions obtained from sensors deployed into a volcanic caldera (Los Humeros, in Puebla, Mexico), ii) regional correlograms functions between two stations of the National Seismological Service (SSN, Servicio Sismológico Nacional in Spanish), and iii) surface wave seismic record for an earthquake located in the Pacific Ocean coast of Mexico and recorded by the SSN. This work is supported by the GEMEX project (Geothermal Europe-Mexico consortium).

  1. Evaluation of Shape Parameter Effect on the J-R Curve of Curved CT Specimen Using Limit Load Method

    Energy Technology Data Exchange (ETDEWEB)

    Shin, In Hwan; Park, Chi Yong [Korea Hydro Nuclear Power Corporation, Seoul (Korea, Republic of); Seok, Chang Sung; Koo, Jae Mean [SungKyunKwan University, Suwon (Korea, Republic of)

    2014-07-15

    In this study, the effect of shape parameters on the J-R curves of curved CT specimens was evaluated using the limit load method. Fracture toughness tests considering the shape factors L/W and Rm/t of the specimens were also performed. Thereafter, the J-R curves of the curved CT specimens were compared using the J-integral equation proposed in the ASTM (American Society for Testing and Materials) and limit load solution. The J-R curves of the curved CT specimens were also compared with those of the CWP (curved wide plate), which is regarded to be similar to real pipe and standard specimens.. Finally, the effectiveness of the J-R curve of each curved CT specimen was evaluated. The results of this study can be used for assessing the applicability of curved CT specimens in the accurate evaluation of the fracture toughness of real pipes.

  2. Strain rate behavior of magnetorheological materials

    International Nuclear Information System (INIS)

    Seminuk, Kenneth; Joshi, Vasant; Gump, Jared; Stoltz, Chad; Forbes, Jerry

    2014-01-01

    Strain rate response of two Hydroxyl-terminated Polybutadiene/ Iron (HTPB/Fe) compositions under electromagnetic fields has been investigated using a Split Hopkinson Pressure bar arrangement equipped with aluminum bars. Two HTPB/Fe compositions were developed, the first without plasticizer and the second containing plasticizer. Samples were tested with and without the application of a 0.01 Tesla magnetic field. Strain gauge data taken from the Split Hopkinson Pressure Bar has been used to determine the extent of change in mechanical properties by inducing a mild electromagnetic field onto each sample. Raw data from strain gages was processed using commercial software (Signo) and Excel spreadsheet. It is of particular interest to determine whether the mechanical properties of binder systems can be manipulated by adding ferrous or Magnetostrictive particulates. Data collected from the Split Hopkinson Pressure bar indicate changes in the Mechanical Stress-Strain curves and suggest that the impedance of a binder system can be altered by means of a magnetic field.

  3. Utilizing Photogrammetry and Strain Gage Measurement to Characterize Pressurization of an Inflatable Module

    Science.gov (United States)

    Valle, Gerard D.; Selig, Molly; Litteken, Doug; Oliveras, Ovidio

    2012-01-01

    This paper documents the integration of a large hatch penetration into an inflatable module. This paper also documents the comparison of analytical load predictions with measured results utilizing strain measurement. Strain was measured by utilizing photogrammetric measurement and through measurement obtained from strain gages mounted to selected clevises that interface with the structural webbings. Bench testing showed good correlation between strain measurement obtained from an extensometer and photogrammetric measurement especially after the fabric has transitioned through the low load/high strain region of the curve. Test results for the full-scale torus showed mixed results in the lower load and thus lower strain regions. Overall strain, and thus load, measured by strain gages and photogrammetry tracked fairly well with analytical predictions. Methods and areas of improvements are discussed.

  4. Strain measurement in concrete using embedded carbon roving-based sensors

    Energy Technology Data Exchange (ETDEWEB)

    Quadflieg, Till; Gries, Thomas [RWTH Aachen Univ. (Germany). Inst. fuer Textiltechnik (ITA); Stolyarov, Oleg [St. Petersburg Polytechnic Univ. (Russian Federation)

    2016-11-01

    This paper presents the results of the application of carbon rovings as strain sensors for measuring the strain in concrete. In this work, three types of electrically conductive carbon roving with different characteristics were used. The possibility of using carbon rovings as a strain sensor is demonstrated via measurements in tensile and four point bending tests. The experimental setups and methods for measuring the electrical resistance of carbon roving in the roving and concrete are described. The results of the characterization of the electrical behavior as a function of strain of carbon rovings and concrete are presented and discussed. The obtained results indicate that the strain range of carbon rovings optimally corresponds to the strain range of concrete. This characteristic behavior makes the carbon rovings well suited for the use as strain sensors. A good correlation has been found between the electrical resistance-strain curve of the carbon roving and the measurements in the concrete.

  5. Interpreting the ROC curve from the radiologist's point of view: the diagnostician operating choice (DOC) curve

    Science.gov (United States)

    Beam, Craig A.; Conant, Emily F.; Krupinski, Elizabeth A.; Kundel, Harold L.; Sickles, Edward A.

    2005-04-01

    We introduce an interesting interpretation of the ROC Curve that, subsequently, opens a new research paradigm. We define the "Diagnostician Operating Choice" (DOC) Curve to be the set of all (True Positive Probability/True Negative Probability) or ("skill in diseased population"/"skill in non-diseased population" when considered from the diagnostician's perspective) options made available to a particular radiologist when interpreting a particular diagnostic technology. The DOC Curve is, thus, the choice set presented to the diagnostician by their interaction with the technology. This new paradigm calls for tools that can measure the particular choice set of any particular individual radiologist interpreting a particular technology when applied in a particular clinical setting. Fundamental requirements for this paradigm are for the DOC Curve to be unique to individuals and constant across similar experimental conditions. To investigate constancy, we analyzed data from a reading study of 10 radiologists. Each radiologist interpreted the same set of 148 screening mammograms twice using a modified version of BI-RADS. ROC Curves for each radiologist were computed and compared between the two reading occasions with the CORROC2 program. None of the areas were statistically significantly different (p<0.05), providing confirmation (but not proof) of constancy across the two reading conditions. The DOC Curve paradigm suggests new areas of research focusing on the behavior in individuals interacting with technology. A clear need is for more efficient estimation of individual DOC Curves based on limited case sets. Paradoxically, the answer to this last problem might lie in using large population-based ("MRMC") studies to develop highly efficient and externally validated standardized testing tools for assessment of the individual.

  6. Creating A Light Curve Using Gathered Data

    Science.gov (United States)

    Wiggs, Joseph; Stolarz, S. A.; DePorto, R. W.; Shake, W. J.; Piper, M.; Linder, T. R.; Holmes, R.; Conwell, J.

    2012-01-01

    Our group of students with the support of educators and astronomers carried out a program to do astrometric and photometric analysis on the asteroid 2000 SO1 with the objective of obtaining a more in depth analysis of this asteroid and publishing light curve data describing the period of the asteroid. We chose our target asteroid using the minor planet center database, choosing an object that would have an acceptable Right Ascension, Declination, magnitude, and air mass for the ARO (Astronomical Research Observatory)-30 inch telescope operated by the SKYNET program. Our journey began with using Astrometrica for the IASC/WISE Program to identify and find new asteroids in the sky and add data to the Minor Planet Center Database. We then used MPO (Minor Planet Observatory) Canopus to form a light curve and conduct a fourier analysis on an example asteroid to familiarize ourselves with the program and used the program again to conduct fourier analysis on asteroid 2000 SO1. The educational goal in mind was to (a) learn the process of collecting and analyzing data using Astrometrica, MPO Canopus, the Minor Planet Center, and SKYNET and (b) create a poster to display the steps used in the process of surveying taken images and the production of a light curve. We collected 300 images a night, while discarding all the corrupted images, until we had enough data to accurately represent the object.Our work was successful due to resources from; Eastern Illinois University's Physics Department, the Astronomical Research Observatory, the University of Chicago's Yerkes Observatory, the SKYNET network, NASA's IASC/WISE (International Astronomical Search Collaboration/ Wide-Field Infrared Survey Explorer), NITARP (NASA/IPAC Teacher Archive Research Program) and Lincoln-Way North High School.

  7. Local strain exerted on Nb3Sn filaments in an ITER strand

    International Nuclear Information System (INIS)

    Osamura, Kozo; Machiya, Shutaro; Harjo, Stefanus; Nakamoto, Tatsushi; Cheggour, Najib; Nijhuis, Arend

    2015-01-01

    As part of an international project to benchmark facilities for measuring the strain dependence of critical current in International Thermonuclear Experimental Reactor (ITER) Nb 3 Sn strands, direct measurement of local strain exerted on Nb 3 Sn filaments was attempted at cryogenic temperature by means of a pulsed neutron technique. The lattice axial strain increased linearly with a slope close to unity against applied strain, while the thermal axial strain was −0.22% at 8.5 K. As a result, the force-free strain was evaluated to be 0.22–0.23%. This key parameter should provide an accurate estimate of the peak location of critical current versus applied strain. The lattice transverse strain decreased linearly as a function of applied strain with a slope of 0.33–0.34. The lattice strains of the Nb and Cu components were also measured and their behavior was analyzed by computing diffraction elastic moduli based on micromechanics theories. The stress–strain curve calculated according to the rule of mixtures described quite well the macroscopic curve measured for the present ITER Nb 3 Sn strand. (paper)

  8. Arithmetic fundamental groups and moduli of curves

    International Nuclear Information System (INIS)

    Makoto Matsumoto

    2000-01-01

    This is a short note on the algebraic (or sometimes called arithmetic) fundamental groups of an algebraic variety, which connects classical fundamental groups with Galois groups of fields. A large part of this note describes the algebraic fundamental groups in a concrete manner. This note gives only a sketch of the fundamental groups of the algebraic stack of moduli of curves. Some application to a purely topological statement, i.e., an obstruction to the subjectivity of Johnson homomorphisms in the mapping class groups, which comes from Galois group of Q, is explained. (author)

  9. Elliptic Tales Curves, Counting, and Number Theory

    CERN Document Server

    Ash, Avner

    2012-01-01

    Elliptic Tales describes the latest developments in number theory by looking at one of the most exciting unsolved problems in contemporary mathematics--the Birch and Swinnerton-Dyer Conjecture. The Clay Mathematics Institute is offering a prize of 1 million to anyone who can discover a general solution to the problem. In this book, Avner Ash and Robert Gross guide readers through the mathematics they need to understand this captivating problem. The key to the conjecture lies in elliptic curves, which are cubic equations in two variables. These equations may appear simple, yet they arise from

  10. Operators and higher genus mirror curves

    Energy Technology Data Exchange (ETDEWEB)

    Codesido, Santiago [Département de Physique Théorique et section de Mathématiques,Université de Genève,Genève, CH-1211 (Switzerland); Gu, Jie [Laboratoire de Physique Théorique de l’École Normale Supérieure,CNRS, PSL Research University,Sorbonne Universités, UPMC, 75005 Paris (France); Mariño, Marcos [Département de Physique Théorique et section de Mathématiques,Université de Genève,Genève, CH-1211 (Switzerland)

    2017-02-17

    We perform further tests of the correspondence between spectral theory and topological strings, focusing on mirror curves of genus greater than one with nontrivial mass parameters. In particular, we analyze the geometry relevant to the SU(3) relativistic Toda lattice, and the resolved ℂ{sup 3}/ℤ{sub 6} orbifold. Furthermore, we give evidence that the correspondence holds for arbitrary values of the mass parameters, where the quantization problem leads to resonant states. We also explore the relation between this correspondence and cluster integrable systems.

  11. J-holomorphic curves and symplectic topology

    CERN Document Server

    McDuff, Dusa

    2012-01-01

    The theory of J-holomorphic curves has been of great importance since its introduction by Gromov in 1985. In mathematics, its applications include many key results in symplectic topology. It was also one of the main inspirations for the creation of Floer homology. In mathematical physics, it provides a natural context in which to define Gromov-Witten invariants and quantum cohomology, two important ingredients of the mirror symmetry conjecture. The main goal of this book is to establish the fundamental theorems of the subject in full and rigorous detail. In particular, the book contains comple

  12. INFLUENCE OF MOVING LOADS ON CURVED BRIDGES

    OpenAIRE

    Thamer A. Z*, Jabbbar S. A

    2016-01-01

    The behavior of a curved slab bridge decks with uniform thickness under moving load is investigated in this study. Three radii of curvature "R" are used (25, 50 and 75m) along with the straight bridge, R = ∞. The decks are simply supported or clamped along the radial edges and free at the circular edges. The AASHTO[1] standard axle load of the truck H20-44 is used and assumed to move in three track positions on the bridge. The finite element method is employed for the analysis and the ANSYS 5...

  13. Path Integrals and Anomalies in Curved Space

    Energy Technology Data Exchange (ETDEWEB)

    Louko, Jorma [University of Nottingham (United Kingdom)

    2007-04-07

    Bastianelli and van Nieuwenhuizen's monograph 'Path Integrals and Anomalies in Curved Space' collects in one volume the results of the authors' 15-year research programme on anomalies that arise in Feynman diagrams of quantum field theories on curved manifolds. The programme was spurred by the path-integral techniques introduced in Alvarez-Gaume and Witten's renowned 1983 paper on gravitational anomalies which, together with the anomaly cancellation paper by Green and Schwarz, led to the string theory explosion of the 1980s. The authors have produced a tour de force, giving a comprehensive and pedagogical exposition of material that is central to current research. The first part of the book develops from scratch a formalism for defining and evaluating quantum mechanical path integrals in nonlinear sigma models, using time slicing regularization, mode regularization and dimensional regularization. The second part applies this formalism to quantum fields of spin 0, 1/2, 1 and 3/2 and to self-dual antisymmetric tensor fields. The book concludes with a discussion of gravitational anomalies in 10-dimensional supergravities, for both classical and exceptional gauge groups. The target audience is researchers and graduate students in curved spacetime quantum field theory and string theory, and the aims, style and pedagogical level have been chosen with this audience in mind. Path integrals are treated as calculational tools, and the notation and terminology are throughout tailored to calculational convenience, rather than to mathematical rigour. The style is closer to that of an exceedingly thorough and self-contained review article than to that of a textbook. As the authors mention, the first part of the book can be used as an introduction to path integrals in quantum mechanics, although in a classroom setting perhaps more likely as supplementary reading than a primary class text. Readers outside the core audience, including this reviewer, will

  14. ERROR VS REJECTION CURVE FOR THE PERCEPTRON

    OpenAIRE

    PARRONDO, JMR; VAN DEN BROECK, Christian

    1993-01-01

    We calculate the generalization error epsilon for a perceptron J, trained by a teacher perceptron T, on input patterns S that form a fixed angle arccos (J.S) with the student. We show that the error is reduced from a power law to an exponentially fast decay by rejecting input patterns that lie within a given neighbourhood of the decision boundary J.S = 0. On the other hand, the error vs. rejection curve epsilon(rho), where rho is the fraction of rejected patterns, is shown to be independent ...

  15. An Autocorrelation Term Method for Curve Fitting

    OpenAIRE

    Houston, Louis M.

    2013-01-01

    The least-squares method is the most popular method for fitting a polynomial curve to data. It is based on minimizing the total squared error between a polynomial model and the data. In this paper we develop a different approach that exploits the autocorrelation function. In particular, we use the nonzero lag autocorrelation terms to produce a system of quadratic equations that can be solved together with a linear equation derived from summing the data. There is a maximum of solutions when th...

  16. Task 4 Improvised Nuclear Device Response Curves

    Energy Technology Data Exchange (ETDEWEB)

    Alai, Maureen [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Neuscamman, Stephanie [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-05-31

    LLNL performed fallout and nuclear blast modeling for the 60 cities using the NARAC modeling system and predominant weather patterns determined in a previous Task 4 effort. LLNL performed model simulations and analyses to identify and provide response curves (expressed as two-dimensional contours) for radioactive fallout deposition, transport, population, and blast overpressure as a function of yield, weather, location and time. These contours can then be further combined and correlated with infrastructure and population databases to estimate city specific effects on KPFs such as impacted infrastructure and casualty rates.

  17. Localization of nonlinear excitations in curved waveguides

    DEFF Research Database (Denmark)

    Gaididei, Yu. B.; Christiansen, Peter Leth; Kevrekidis, P. G.

    2005-01-01

    numerical simulations of the nonlinear problem and in this case localized excitations are found to persist. We found also interesting relaxational dynamics. Analogies of the present problem in context related to atomic physics and particularly to Bose–Einstein condensation are discussed.......Motivated by the examples of a curved waveguide embedded in a photonic crystal and cold atoms moving in a waveguide created by a spatially inhomogeneous electromagnetic field, we examine the effects of geometry in a 'quantum channel' of parabolic form. Starting with the linear case we derive exact...

  18. Curves and tables of neutron cross sections

    International Nuclear Information System (INIS)

    Nakagawa, Tsuneo; Asami, Tetsuo; Yoshida, Tadashi

    1990-07-01

    Neutron cross-section curves from the Japanese Evaluated Nuclear Data Library version 3, JENDL-3, are presented in both graphical and tabular form for users in a wide range of application areas in the nuclear energy field. The contents cover cross sections for all the main reactions induced by neutrons with an energy below 20 MeV including; total, elastic scattering, capture, and fission, (n,n'), (n,2n), (n,3n), (n,α), (n,p) reactions. The 2200 m/s cross-section values, resonance integrals, and Maxwellian- and fission-spectrum averaged cross sections are also tabulated. (author)

  19. Tunable Polymer Fiber Bragg Grating (FBG) Inscription: Fabrication of Dual-FBG Temperature Compensated Polymer Optical Fiber Strain Sensors

    DEFF Research Database (Denmark)

    Yuan, Scott Wu; Stefani, Alessio; Bang, Ole

    2012-01-01

    We demonstrate stable wavelength tunable inscription of polymer optical fiber Bragg gratings (FBGs). By straining the fiber during FBG inscription, we linearly tune the center wavelength over 7 nm with less than 1% strain. Above 1% strain, the tuning curve saturates and we show a maximum tuning...... of 12 nm with 2.25% strain. We use this inscription method to fabricate a dual-FBG strain sensor in a poly (methyl methacrylate) single-mode microstructured polymer optical fiber and demonstrate temperature compensated strain sensing around 850 nm....

  20. Photothermal strain imaging

    Science.gov (United States)

    Choi, Changhoon; Ahn, Joongho; Jeon, Seungwan; Kim, Chulhong

    2017-07-01

    Vulnerable plaques are the major cause of cardiovascular disease, but they are difficult to detect with conventional intravascular imaging techniques. Techniques are needed to identify plaque vulnerability based on the presence of lipids in plaque. Thermal strain imaging (TSI) is an imaging technique based on ultrasound (US) wave propagation speed, which varies with the medium temperature. In TSI, the strain that occurs during tissue temperature change can be used for lipid detection because it has a different tendency depending on the type of tissue. Here, we demonstrate photothermal strain imaging (pTSI) using an intravascular ultrasound catheter. pTSI is performed by slightly and selectively heating lipid using a relatively inexpensive continuous laser source. We applied a speckle-tracking algorithm to US B-mode images for strain calculations. As a result, the strain produced in porcine fat was different from the strain produced in water-bearing gelatin phantom, which made it possible to distinguish the two. This suggests that pTSI could potentially be a way of differentiating lipids in coronary artery.

  1. Analysis of velocity planning interpolation algorithm based on NURBS curve

    Science.gov (United States)

    Zhang, Wanjun; Gao, Shanping; Cheng, Xiyan; Zhang, Feng

    2017-04-01

    To reduce interpolation time and Max interpolation error in NURBS (Non-Uniform Rational B-Spline) inter-polation caused by planning Velocity. This paper proposed a velocity planning interpolation algorithm based on NURBS curve. Firstly, the second-order Taylor expansion is applied on the numerator in NURBS curve representation with parameter curve. Then, velocity planning interpolation algorithm can meet with NURBS curve interpolation. Finally, simulation results show that the proposed NURBS curve interpolator meet the high-speed and high-accuracy interpolation requirements of CNC systems. The interpolation of NURBS curve should be finished.

  2. Rigid geometry of curves and their Jacobians

    CERN Document Server

    Lütkebohmert, Werner

    2016-01-01

    This book presents some of the most important aspects of rigid geometry, namely its applications to the study of smooth algebraic curves, of their Jacobians, and of abelian varieties - all of them defined over a complete non-archimedean valued field. The text starts with a survey of the foundation of rigid geometry, and then focuses on a detailed treatment of the applications. In the case of curves with split rational reduction there is a complete analogue to the fascinating theory of Riemann surfaces. In the case of proper smooth group varieties the uniformization and the construction of abelian varieties are treated in detail. Rigid geometry was established by John Tate and was enriched by a formal algebraic approach launched by Michel Raynaud. It has proved as a means to illustrate the geometric ideas behind the abstract methods of formal algebraic geometry as used by Mumford and Faltings. This book should be of great use to students wishing to enter this field, as well as those already working in it.

  3. Analysis of the vitreoretinal surgery learning curve.

    Science.gov (United States)

    Martín-Avià, J; Romero-Aroca, P

    2017-06-01

    To describe intra- and post-operative complications, as well as the evolution of the surgical technique in first 4years of work of a novice retina surgeon, and evaluate minimal learning time required to reduce its complications, deciding which pathologies should still be referred to higher level hospitals, until further experience may be achieved. A study was conducted on patients that had undergone vitreoretinal surgery by a novice surgeon in Tarragona between 23rd October 2007 and 31st December 2011. The primary diagnosis, surgeon learning time, surgical technique, intra-operative and post-operative complications were recorded. A total of 247 surgeries were studied. The percentage of use of 20G and 23G calibres during the time, marks a change towards trans-conjunctival surgery from the ninth trimester (98 surgeries). Surgical complications decreased towards twelfth trimester (130 surgeries) with an increase in the previous months. The shift towards 23G technique around 100 surgeries is interpreted as greater comfort and safety by the surgeon. Increased surgical complications during the following months until its decline around 130 surgeries can be interpreted as an 'overconfidence'. It is arguable that the learning curve is slower than what the surgeon believes. An individual analysis of the complications and surgical outcomes is recommended to ascertain the status of the learning curve. Copyright © 2016 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L.U. All rights reserved.

  4. Handbook of elliptic and hyperelliptic curve cryptography

    CERN Document Server

    Cohen, Henri; Avanzi, Roberto; Doche, Christophe; Lange, Tanja; Nguyen, Kim; Vercauteren, Frederik

    2005-01-01

    … very comprehensive coverage of this vast subject area … a useful and essential treatise for anyone involved in elliptic curve algorithms … this book offers the opportunity to grasp the ECC technology with a diversified and comprehensive perspective. … This book will remain on my shelf for a long time and will land on my desk on many occasions, if only because the coverage of the issues common to factoring and discrete log cryptosystems is excellent.-IACR Book Reviews, June 2011… the book is designed for people who are working in the area and want to learn more about a specific issue. The chapters are written to be relatively independent so that readers can focus on the part of interest for them. Such readers will be grateful for the excellent index and extensive bibliography. … the handbook covers a wide range of topics and will be a valuable reference for researchers in curve-based cryptography. -Steven D. Galbraith, Mathematical Reviews, Issue 2007f.

  5. Focal Conic Flower Textures at Curved Interfaces

    Directory of Open Access Journals (Sweden)

    Daniel A. Beller

    2013-12-01

    Full Text Available Focal conic domains (FCDs in smectic-A liquid crystals have drawn much attention, both for their exquisitely structured internal form and for their ability to direct the assembly of micromaterials and nanomaterials in a variety of patterns. A key to directing FCD assembly is control over the eccentricity of the domain. Here, we demonstrate a new paradigm for creating spatially varying FCD eccentricity by confining a hybrid-aligned smectic with curved interfaces. In particular, we manipulate interface behavior with colloidal particles in order to experimentally produce two examples of what has recently been dubbed the flower texture [C. Meyer et al., Focal Conic Stacking in Smectic A Liquid Crystals: Smectic Flower and Apollonius Tiling, Materials 2, 499, 2009MATEG91996-194410.3390/ma2020499], where the focal hyperbolæ diverge radially outward from the center of the texture, rather than inward as in the canonical éventail or fan texture. We explain how this unconventional assembly can arise from appropriately curved interfaces. Finally, we present a model for this system that applies the law of corresponding cones, showing how FCDs may be embedded smoothly within a “background texture” of large FCDs and concentric spherical layers, in a manner consistent with the qualitative features of the smectic flower. Such understanding could potentially lead to disruptive liquid-crystal technologies beyond displays, including patterning, smart surfaces, microlens arrays, sensors, and nanomanufacturing.

  6. Modeling of alpha mass-efficiency curve

    International Nuclear Information System (INIS)

    Semkow, T.M.; Jeter, H.W.; Parsa, B.; Parekh, P.P.; Haines, D.K.; Bari, A.

    2005-01-01

    We present a model for efficiency of a detector counting gross α radioactivity from both thin and thick samples, corresponding to low and high sample masses in the counting planchette. The model includes self-absorption of α particles in the sample, energy loss in the absorber, range straggling, as well as detector edge effects. The surface roughness of the sample is treated in terms of fractal geometry. The model reveals a linear dependence of the detector efficiency on the sample mass, for low masses, as well as a power-law dependence for high masses. It is, therefore, named the linear-power-law (LPL) model. In addition, we consider an empirical power-law (EPL) curve, and an exponential (EXP) curve. A comparison is made of the LPL, EPL, and EXP fits to the experimental α mass-efficiency data from gas-proportional detectors for selected radionuclides: 238 U, 230 Th, 239 Pu, 241 Am, and 244 Cm. Based on this comparison, we recommend working equations for fitting mass-efficiency data. Measurement of α radioactivity from a thick sample can determine the fractal dimension of its surface

  7. Defining a learning curve for laparoscopic cardiomyotomy.

    Science.gov (United States)

    Grotenhuis, Brechtje A; Wijnhoven, Bas P L; Jamieson, Glyn G; Devitt, Peter G; Bessell, Justin R; Watson, David I

    2008-08-01

    This study was designed to determine whether there is a learning curve for laparoscopic cardiomyotomy for the treatment of achalasia. All patients who underwent a primary laparoscopic cardiomyotomy for achalasia between 1992 and 2006 in our hospitals were identified from a prospective database. The institutional and the individual surgeon's learning experiences were assessed based on operative and clinical outcome parameters. The outcomes of cardiomyotomies performed by consultant surgeons versus supervised trainees also were compared. A total of 186 patients met the inclusion criteria; 144 procedures were undertaken by consultant surgeons and 42 by a surgical trainee. The length of operation decreased after the first ten cases in both the institutional and each individual experience. The rate of conversion to open surgery also was significantly higher in the first 20 cases performed. Intraoperative complications, overall satisfaction with the outcome, reoperation rate, and postoperative dysphagia were not associated with the institutional or the surgeon's operative experience. Although the length of the operation was greater for surgical trainees (93 versus 79 minutes; p learning curve for laparoscopic cardiomyotomy for achalasia can be defined. The clinical outcome for laparoscopic cardiomyotomy does not differ between supervised surgical trainees and consultant surgeons.

  8. Coexistence Curve of Perfluoromethylcyclohexane-Isopropyl Alcohol

    Science.gov (United States)

    Jacobs, D. T.; Kuhl, D. E.; Selby, C. E.

    1996-01-01

    The coexistence curve of the binary fluid mixture perfluoromethylcyclohexane-isopropyl alcohol was determined by precisely measuring the refractive index both above and below its upper critical consolute point. Sixty-seven two-phase data points were obtained over a wide range of reduced temperatures, 10(exp -5) less than t less than 2.5 x 10(exp -1), to determine the location of the critical point: critical temperature=89.901 C, and critical composition = 62.2% by volume perfluoromethylcyclohexane. These data were analyzed to determine the critical exponent 8 close to the critical point, the amplitude B, and the anomaly in the diameter. The volume-fraction coexistence curve is found to be as symmetric as any composition like variable. Correction to scaling is investigated as well as the need for a crossover theory. A model is proposed that describes the asymptotic approach to zero of the effective exponent Beta, which allows an estimation of the temperature regime free of crossover effects.

  9. Strain: Fact or Fiction?

    Science.gov (United States)

    Heilbronner, Renée

    2017-04-01

    2017 marks the 50th anniversary of the publication of John Ramsay's well known textbook "Folding and Fracturing of Rocks" - ... and the 30th anniversary of the rejection of a rather less well known paper entitled "Strain: Fact or Fiction?" submitted by Renée Panozzo to the Journal of Structural Geology. The gist of the paper was simple and straight forward: it was argued that not every fabric that can be observed in deformed rocks is necessarily a measure of the amount of strain the rock incurred. A distinction was made between a general "fabric", i.e., the traceable geometry of grain boundaries, for example, and a so-called "strain fabric", i.e., the model geometry that would result from homogeneously straining an initially isotropic fabric and that would exhibit at least orthorhombic symmetry. To verify if a given fabric was indeed a strain fabric it was therefore suggested to use the SURFOR method (published by Panozzo) and to carry out a so-called strain test, i.e., a check of symmetry, before interpreting the results of a fabric analysis in terms of strain. The problem with the paper was that it was very obviously written out of frustration. The frustration came form having reviewed a number of manuscripts which tried to use the then novel SURFOR method for strain analysis without first checking if the the fabric was a indeed a "strain fabric" or not, and then blaming the SURFOR method for producing ambiguous results. As a result, the paper was not exactly well balanced and carefully thought out. It was considered "interesting but not scholarly" by one of the reviewers and down-right offensive by the second. To tell the truth, however, the paper was not formally rejected. The editor Sue Treagus strongly encouraged Panozzo to revise the paper, ... and 30 years later, I will follow her advise and offer a revised paper as a tribute to John Ramsay. To quote from the original manuscript: "We should be a little more impressed that strain works so well, and less

  10. A comparison of site index curves for northern hardwood species.

    Science.gov (United States)

    Willard H. Carmean

    1979-01-01

    Gives an inventory and compares site index curves for 13 northern hardwood species. Differences illustrate the need for more precise site index curves that are applicable to local soil and site conditions.

  11. ON THE TOPOLOGY OF MECHANISMS DESIGNED FOR CURVES GENERATION

    Directory of Open Access Journals (Sweden)

    MEREUTA Elena

    2008-07-01

    Full Text Available The paper presents some mechanisms used for generating simple or complex curves. The mechanisms are shown in different positions and for some special curves the demonstrations are performed.

  12. Curve of Spee and Its Relationship with Dentoskeletal Morphology

    Directory of Open Access Journals (Sweden)

    Prerna Raje Batham

    2013-01-01

    Conclusion: The curve of Spee is related to various dentoskeletal variables. Thus, the determination of this relationship is useful to assess the feasibility of leveling the curve of Spee by orthodontic treatment.

  13. Path Integrals and Anomalies in Curved Space

    International Nuclear Information System (INIS)

    Louko, Jorma

    2007-01-01

    Bastianelli and van Nieuwenhuizen's monograph 'Path Integrals and Anomalies in Curved Space' collects in one volume the results of the authors' 15-year research programme on anomalies that arise in Feynman diagrams of quantum field theories on curved manifolds. The programme was spurred by the path-integral techniques introduced in Alvarez-Gaume and Witten's renowned 1983 paper on gravitational anomalies which, together with the anomaly cancellation paper by Green and Schwarz, led to the string theory explosion of the 1980s. The authors have produced a tour de force, giving a comprehensive and pedagogical exposition of material that is central to current research. The first part of the book develops from scratch a formalism for defining and evaluating quantum mechanical path integrals in nonlinear sigma models, using time slicing regularization, mode regularization and dimensional regularization. The second part applies this formalism to quantum fields of spin 0, 1/2, 1 and 3/2 and to self-dual antisymmetric tensor fields. The book concludes with a discussion of gravitational anomalies in 10-dimensional supergravities, for both classical and exceptional gauge groups. The target audience is researchers and graduate students in curved spacetime quantum field theory and string theory, and the aims, style and pedagogical level have been chosen with this audience in mind. Path integrals are treated as calculational tools, and the notation and terminology are throughout tailored to calculational convenience, rather than to mathematical rigour. The style is closer to that of an exceedingly thorough and self-contained review article than to that of a textbook. As the authors mention, the first part of the book can be used as an introduction to path integrals in quantum mechanics, although in a classroom setting perhaps more likely as supplementary reading than a primary class text. Readers outside the core audience, including this reviewer, will gain from the book a

  14. Strain rate dependent hardening of DP600 sheet metal for large strains under in-plane biaxial loadings

    Science.gov (United States)

    Liu, W.; Guines, D.; Léotoing, L.; Ragneau, E.

    2016-10-01

    In this work, an in-plane biaxial tensile test of cruciform specimen is performed to identify the visco-plastic hardening behaviour of metallic sheets for both large strains and intermediate strain rates at room temperature. Firstly, an optimal shape of the specimen is suggested. Then, dynamic biaxial tensile tests are carried out for a dual phase DP600 steel sheet. Experimental forces on the two axes of the specimen are measured during the test and strains in the central area of the specimen are post-treated by means of Digital Image Correlation (DIC) technique. Finally, considering a Hill48 anisotropic yield criterion, two strain rate dependent hardening laws are identified thanks to an inverse procedure based on a Finite Element (FE) modelling of the biaxial tensile test and on the experimental data mentioned above. The identified biaxial flow curves are then compared with the ones from a classical uniaxial tensile test.

  15. High rank elliptic curves with torsion ℤ/4ℤ.

    Science.gov (United States)

    Khoshnam, Foad; Moody, Dustin

    2016-01-01

    Working over the field ℚ( t ), Kihara constructed an elliptic curve with torsion group ℤ/4ℤ and five independent rational points, showing the rank is at least five. Following his approach, we give a new infinite family of elliptic curves with torsion group ℤ/4ℤ and rank at least five. This matches the current record for such curves. In addition, we give specific examples of these curves with high ranks 10 and 11.

  16. Illusory Paschen curves associated with strongly electronegative gases

    DEFF Research Database (Denmark)

    McAllister, Iain Wilson

    1991-01-01

    Using analytical linear regression analysis, it is shown that, for a strongly electronegative gas, the (direct) breakdown voltage curve obtained with a moderately nonuniform field is effectively linear. For a strongly electronegative gas, breakdown voltage measurements made on a moderately...... nonuniform field test gap give rise to an apparently liner curve. The curve can be designated a Paschen curve, but the erroneous nature of this designation becomes apparent from a linear regression analysis of the experimental breakdown data...

  17. Black hole entropy, curved space and monsters

    International Nuclear Information System (INIS)

    Hsu, Stephen D.H.; Reeb, David

    2008-01-01

    We investigate the microscopic origin of black hole entropy, in particular the gap between the maximum entropy of ordinary matter and that of black holes. Using curved space, we construct configurations with entropy greater than the area A of a black hole of equal mass. These configurations have pathological properties and we refer to them as monsters. When monsters are excluded we recover the entropy bound on ordinary matter S 3/4 . This bound implies that essentially all of the microstates of a semiclassical black hole are associated with the growth of a slightly smaller black hole which absorbs some additional energy. Our results suggest that the area entropy of black holes is the logarithm of the number of distinct ways in which one can form the black hole from ordinary matter and smaller black holes, but only after the exclusion of monster states

  18. Talking Curves at the Montreaux+5 Conference

    DEFF Research Database (Denmark)

    Leander, Anna

    This tale is drawn from fieldwork I did at the Montreux+5 Conference in (yes!) Montreux, 11-13 December 2013. The conference was organized by those who initiated, sponsored and promoted the Montreux Document on Pertinent International Legal Obligations and Good Practices for States related...... in armed conflicts”. To this end the MD spells out “pertinent legal obligations” (on four pages and a small paragraph) but also “best practices” (on eleven full pages). The Montreux+5 Conference celebrated the document’s fifth anniversary. The party was held to review the MD but also to promote it. Invited...... were the signatory states, non-signatory states, but also assorted companies, NGOs and academics (including myself) susceptible of having a view on the topic. I want to tell the political tale of how talking in curves around the MD at the Montreux+5 “translated” security in plural, non...

  19. Modelling critical NDVI curves in perennial ryegrass

    DEFF Research Database (Denmark)

    Gislum, R; Boelt, B

    2010-01-01

      The use of optical sensors to measure canopy reflectance and calculate crop index as e.g. normalized difference vegetation index (NDVI) is widely used in agricultural crops, but has so far not been implemented in herbage seed production. The present study has the purpose to develop a critical...... NDVI curve where the critical NDVI, defined as the minimum NDVI obtained to achieve a high seed yield, will be modelled during the growing season. NDVI measurements were made at different growing degree days (GDD) in a three year field experiment where different N application rates were applied....... There was a clear maximum in the correlation coefficient between seed yield and NDVI in the period from approximately 700 to 900 GDD. At this time there was an exponential relationship between NDVI and seed yield where highest seed yield were at NDVI ~0.9. Theoretically the farmers should aim for an NDVI of 0...

  20. Environmental management by the learning curve

    International Nuclear Information System (INIS)

    Fehr, M.

    2003-01-01

    This is a futuristic appreciation of waste management challenges and their solution by means of good management models. A literature review, administrative initiatives, research results, and experiences from practice are combined in this study to render an evolutionary picture of the change in paradigm relative to municipal solid waste possible to occur between 2000 and 2025. The principal stages of progress in the 25 years studied were: the correct characterization of municipal solid waste as a function of geographical location and recycling potential, the divided collection model and its corresponding learning curve, correct opportunity cost accounting tools, and the generally admitted and accepted changeover of municipal solid waste treatment from a technical to a management problem. It is reported that as a result of this progress, the municipal landfill is a species in extinction. Regional landfills with long life spans are the rule in 2025

  1. FUZZY ACCEPTANCE SAMPLING AND CHARACTERISTIC CURVES

    Directory of Open Access Journals (Sweden)

    Ebru Turano?lu

    2012-02-01

    Full Text Available Acceptance sampling is primarily used for the inspection of incoming or outgoing lots. Acceptance sampling refers to the application of specific sampling plans to a designated lot or sequence of lots. The parameters of acceptance sampling plans are sample sizes and acceptance numbers. In some cases, it may not be possible to define acceptance sampling parameters as crisp values. These parameters can be expressed by linguistic variables. The fuzzy set theory can be successfully used to cope with the vagueness in these linguistic expressions for acceptance sampling. In this paper, the main distributions of acceptance sampling plans are handled with fuzzy parameters and their acceptance probability functions are derived. Then the characteristic curves of acceptance sampling are examined under fuzziness. Illustrative examples are given.

  2. Hardware Accelerators for Elliptic Curve Cryptography

    Directory of Open Access Journals (Sweden)

    C. Puttmann

    2008-05-01

    Full Text Available In this paper we explore different hardware accelerators for cryptography based on elliptic curves. Furthermore, we present a hierarchical multiprocessor system-on-chip (MPSoC platform that can be used for fast integration and evaluation of novel hardware accelerators. In respect of two application scenarios the hardware accelerators are coupled at different hierarchy levels of the MPSoC platform. The whole system is implemented in a state of the art 65 nm standard cell technology. Moreover, an FPGA-based rapid prototyping system for fast system verification is presented. Finally, a metric to analyze the resource efficiency by means of chip area, execution time and energy consumption is introduced.

  3. Nonlinear gravitons and curved twistor theory

    International Nuclear Information System (INIS)

    Penrose, R.

    1976-01-01

    A new approach to the quantization of general relativity is suggested in which a state consisting of just one graviton can be described, but in a way which involves both the curvature and nonlinearities of Einstein's theory. It is felt that this approach can be justified solely on its own merits but it also receives striking encouragement from another direction: a surprising mathematical result enables one to construct the general such nonlinear gravitation state from a curved twistor space, the construction being given in terms of one arbitrary holomorphic function of three complex variables. In this way, the approach fits naturally into the general twistor program for the description of quantized fields. (U.K.)

  4. Curved VPH gratings for novel spectrographs

    Science.gov (United States)

    Clemens, J. Christopher; O'Donoghue, Darragh; Dunlap, Bart H.

    2014-07-01

    The introduction of volume phase holographic (VPH) gratings into astronomy over a decade ago opened new possibilities for instrument designers. In this paper we describe an extension of VPH grating technology that will have applications in astronomy and beyond: curved VPH gratings. These devices can disperse light while simultaneously correcting aberrations. We have designed and manufactured two different kinds of convex VPH grating prototypes for use in off-axis reflecting spectrographs. One type functions in transmission and the other in reflection, enabling Offnerstyle spectrographs with the high-efficiency and low-cost advantages of VPH gratings. We will discuss the design process and the tools required for modelling these gratings along with the recording layout and process steps required to fabricate them. We will present performance data for the first convex VPH grating produced for an astronomical spectrograph.

  5. Decay curves in coupled, reverberant spaces

    DEFF Research Database (Denmark)

    Balin, Jamilla; Nolan, Melanie; Fernandez Grande, Efren

    2016-01-01

    This study investigates the effect of panel and boundary diffusers in a reverberant space. Diffusers are usually mounted in a reverberation chamber to increase the diffuse sound field as recommended in Annex A of ISO 354. The ISO is not specific about the location or the material of the panels......; the standard only states that the absorption coefficient of a highly absorbing material will increase and approach a maximum value. This value is usually much higher than 1 when diffusers are added. It is also known that the reproducibility of absorption coefficient measurements in reverberation chambers...... is unsatisfying. This study investigates the effect of panel diffusers, in particular considering that their dispositioning in a room can create coupled spaces, decreasing the effective volume of the chamber, and leading to an overestimation of the absorption coefficient. The decay curves are measured in a small...

  6. Analytical extension of curved shock theory

    Science.gov (United States)

    Emanuel, G.

    2018-03-01

    Curved shock theory (CST) is limited to shock waves in a steady, two-dimensional or axisymmetric (2-Ax) flow of a perfect gas. A unique feature of CST is its use of intrinsic coordinates that result in an elegant and useful formulation for flow properties just downstream of a shock. For instance, the downstream effect of upstream vorticity, shock wave curvature, and the upstream pressure gradient along a streamline is established. There have been several attempts to extend CST, as mentioned in the text. Removal of the steady, 2-Ax, and perfect gas limitations, singly or in combination, requires an appropriate formulation of the shock wave's jump relations and the intrinsic coordinate Euler equations. Issues discussed include flow plane versus osculating plane, unsteady flow, vorticity, an imperfect gas, etc. The extension of CST utilizes concepts from differential geometry, such as the osculating plane, streamline torsion, and the Serret-Frenet equations.

  7. Medical learning curves and the Kantian ideal.

    Science.gov (United States)

    Le Morvan, P; Stock, B

    2005-09-01

    A hitherto unexamined problem for the "Kantian ideal" that one should always treat patients as ends in themselves, and never only as a means to other ends, is explored in this paper. The problem consists of a prima facie conflict between this Kantian ideal and the reality of medical practice. This conflict arises because, at least presently, medical practitioners can only acquire certain skills and abilities by practising on live, human patients, and given the inevitability and ubiquity of learning curves, this learning requires some patients to be treated only as a means to this end. A number of ways of attempting to establish the compatibility of the Kantian Ideal with the reality of medical practice are considered. Each attempt is found to be unsuccessful. Accordingly, until a way is found to reconcile them, we conclude that the Kantian ideal is inconsistent with the reality of medical practice.

  8. Topological Sound and Flocking on Curved Surfaces

    Directory of Open Access Journals (Sweden)

    Suraj Shankar

    2017-09-01

    Full Text Available Active systems on curved geometries are ubiquitous in the living world. In the presence of curvature, orientationally ordered polar flocks are forced to be inhomogeneous, often requiring the presence of topological defects even in the steady state because of the constraints imposed by the topology of the underlying surface. In the presence of spontaneous flow, the system additionally supports long-wavelength propagating sound modes that get gapped by the curvature of the underlying substrate. We analytically compute the steady-state profile of an active polar flock on a two-sphere and a catenoid, and show that curvature and active flow together result in symmetry-protected topological modes that get localized to special geodesics on the surface (the equator or the neck, respectively. These modes are the analogue of edge states in electronic quantum Hall systems and provide unidirectional channels for information transport in the flock, robust against disorder and backscattering.

  9. Topological Sound and Flocking on Curved Surfaces

    Science.gov (United States)

    Shankar, Suraj; Bowick, Mark J.; Marchetti, M. Cristina

    2017-07-01

    Active systems on curved geometries are ubiquitous in the living world. In the presence of curvature, orientationally ordered polar flocks are forced to be inhomogeneous, often requiring the presence of topological defects even in the steady state because of the constraints imposed by the topology of the underlying surface. In the presence of spontaneous flow, the system additionally supports long-wavelength propagating sound modes that get gapped by the curvature of the underlying substrate. We analytically compute the steady-state profile of an active polar flock on a two-sphere and a catenoid, and show that curvature and active flow together result in symmetry-protected topological modes that get localized to special geodesics on the surface (the equator or the neck, respectively). These modes are the analogue of edge states in electronic quantum Hall systems and provide unidirectional channels for information transport in the flock, robust against disorder and backscattering.

  10. Beveridge Curve Shifts – Europe 2020 Perspectives

    Directory of Open Access Journals (Sweden)

    Ferent-Pipas Marina

    2016-11-01

    Full Text Available The present paper aligns to the economic policy body of research granting intensive efforts to the sphere of analysing the unemployment rate’s evolution as well as its primary drivers and effects in the context of the Europe 2020 strategy. Considering one of the agenda’s main targets – increasing employability among the European Union’s states, this paper analyses the areas funded by the European Social Fund as well as the country policy specifics in deriving the behaviour of the Beveridge curve associated with the EU-13 countries given the shift of European Union’s funds from old member states to newer ones. As such, the study employs the tools of Simultaneous Equations Systems and examines the impact of four categories of components on the Beveridge curve’s behaviour - structure of the unemployed, labour market and business environment factors as well as business cycles.

  11. Presheaves of Superselection Structures in Curved Spacetimes

    Science.gov (United States)

    Vasselli, Ezio

    2015-04-01

    We show that superselection structures on curved spacetimes that are expected to describe quantum charges affected by the underlying geometry are categories of sections of presheaves of symmetric tensor categories. When an embedding functor is given, the superselection structure is a Tannaka-type dual of a locally constant group bundle, which hence becomes a natural candidate for the role of the gauge group. Indeed, we show that any locally constant group bundle (with suitable structure group) acts on a net of C* algebras fulfilling normal commutation relations on an arbitrary spacetime. We also give examples of gerbes of C* algebras, defined by Wightman fields and constructed using projective representations of the fundamental group of the spacetime, which we propose as solutions for the problem that existence and uniqueness of the embedding functor are not guaranteed.

  12. Endoscopic sleeve gastroplasty: the learning curve.

    Science.gov (United States)

    Hill, Christine; El Zein, Mohamad; Agnihotri, Abhishek; Dunlap, Margo; Chang, Angela; Agrawal, Alison; Barola, Sindhu; Ngamruengphong, Saowanee; Chen, Yen-I; Kalloo, Anthony N; Khashab, Mouen A; Kumbhari, Vivek

    2017-09-01

     Endoscopic sleeve gastroplasty (ESG) is gaining traction as a minimally invasive bariatric treatment. Concern that the learning curve may be slow, even among those proficient in endoscopic suturing, is a barrier to widespread implementation of the procedure. Therefore, we aimed to define the learning curve for ESG in a single endoscopist experienced in endoscopic suturing who participated in a 1-day ESG training program.  Consecutive patients who underwent ESG between February 2016 and November 2016 were included. The performing endoscopist, who is proficient in endoscopic suturing for non-ESG procedures, participated in a 1-day ESG training session before offering ESG to patients. The outcome measurements were length of procedure (LOP) and number of plications per procedure. Nonlinear regression was used to determine the learning plateau and calculate the learning rate.  Twenty-one consecutive patients (8 males), with mean age 47.7 ± 11.2 years and mean body mass index 41.8 ± 8.5 kg/m 2 underwent ESG. LOP decreased significantly across consecutive procedures, with a learning plateau at 101.5 minutes and a learning rate of 7 cases ( P  = 0.04). The number of plications per procedure also decreased significantly across consecutive procedures, with a plateau at 8 sutures and a learning rate of 9 cases ( P  < 0.001). Further, the average time per plication decreased significantly with consecutive procedures, reaching a plateau at 9 procedures ( P  < 0.001).  Endoscopists experienced in endoscopic suturing are expected to achieve a reduction in LOP and number of plications per procedure in successive cases, with progress plateauing at 7 and 9 cases, respectively.

  13. Curved Radio Spectra of Weak Cluster Shocks

    Science.gov (United States)

    Kang, Hyesung; Ryu, Dongsu

    2015-08-01

    In order to understand certain observed features of arc-like giant radio relics such as the rareness, uniform surface brightness, and curved integrated spectra, we explore a diffusive shock acceleration (DSA) model for radio relics in which a spherical shock impinges on a magnetized cloud containing fossil relativistic electrons. Toward this end, we perform DSA simulations of spherical shocks with the parameters relevant for the Sausage radio relic in cluster CIZA J2242.8+5301, and calculate the ensuing radio synchrotron emission from re-accelerated electrons. Three types of fossil electron populations are considered: a delta-function like population with the shock injection momentum, a power-law distribution, and a power law with an exponential cutoff. The surface brightness profile of the radio-emitting postshock region and the volume-integrated radio spectrum are calculated and compared with observations. We find that the observed width of the Sausage relic can be explained reasonably well by shocks with speed {u}{{s}}˜ 3× {10}3 {km} {{{s}}}-1 and sonic Mach number {M}{{s}}˜ 3. These shocks produce curved radio spectra that steepen gradually over (0.1-10){ν }{br} with a break frequency {ν }{br}˜ 1 GHz if the duration of electron acceleration is ˜60-80 Myr. However, the abrupt increase in the spectral index above ˜1.5 GHz observed in the Sausage relic seems to indicate that additional physical processes, other than radiative losses, operate for electrons with {γ }{{e}}≳ {10}4.

  14. Recursions for characteristic numbers of genus one plane curves

    OpenAIRE

    Vakil, Ravi

    2001-01-01

    Characteristic numbers of families of maps of nodal curves to P2 are defined as intersection of natural divisor classes. (This definition agrees with the usual definition for families of plane curves.) Simple recursions for characteristic numbers of genus one plane curves of all degrees are computed.

  15. Retiring the Short-Run Aggregate Supply Curve

    Science.gov (United States)

    Elwood, S. Kirk

    2010-01-01

    The author argues that the aggregate demand/aggregate supply (AD/AS) model is significantly improved--although certainly not perfected--by trimming it of the short-run aggregate supply (SRAS) curve. Problems with the SRAS curve are shown first for the AD/AS model that casts the AD curve as identifying the equilibrium level of output associated…

  16. Learning curve tool applications in DOE materials management activities

    International Nuclear Information System (INIS)

    Lipinski, A.

    1994-01-01

    This paper will examine the application of learning curve theory, an economic theory that quantifies cost savings over time in a labor intensive process. Learning curve theory has been traditionally applied to a production process. This paper examines the application of learning curve theory in cost estimating of waste characterization in storage at a DOE facility

  17. Sensitivity curve measurement and application of radioactivity meter

    International Nuclear Information System (INIS)

    Yao Shunhe; Wang Jianqing; Guo Xiaoqing; Yao Yanling; Li Jingxiu

    2007-01-01

    The paper describes the sensitivity curve measurements and applications for radioactivity meter. The energy-dependent sensitivity curve is established with the activity of standard sources and their corresponding current by constructing functions sub-section. Thus the current-activity ratio is acquired from the sensitivity curve and the calibration of radioactivity meter is solved satisfactorily. (authors)

  18. Curving Concrete : A Method for Manufacturing Double Curved Precast Concrete Panels using a Flexible Mould

    NARCIS (Netherlands)

    Schipper, H.R.; Janssen, B.

    2011-01-01

    Free form architecture with complex geometry brings along new challenges for manufacturers of building components. This paper describes the application of structural mechanics to predict the behaviour of an elastic mould surface, used as formwork for the manufacturing of double curved panels in

  19. Strain superlattices in graphene

    Science.gov (United States)

    Zhang, Yingjie; Kim, Youngseok; Lyding, Joseph; Gilbert, Matthew; Mason, Nadya

    Superlattices have been widely explored to tailor the electronic properties of two-dimensional electron systems. Previous approaches to create superlattices have been limited to periodic potential modulations, either in the form of electrostatic gating or moiré heterostructures. Here we present a new strategy to generate superlattices in 2D materials. We deposit these 2D membranes on a periodic array of dielectric nanospheres, and achieve superlattices with periodic strain modulations. We studied the electronic and magneto-transport properties of strained graphene superlattices, and observed salient features of Dirac point cloning and Hofstadter's butterfly. Furthermore, we were able to tune the transport properties by changing the magnitude of strain in the graphene superlattice. This new degree of freedom provides a novel platform both for fundamental studies of 2D electron correlations and for prospective applications in 2D electronic devices. Y.Z. and N.M. acknowledge support from the National Science Foundation under Grant No. ENG-1434147.

  20. Influence of transient strain rates on material flow stress and microstructure evolution

    Science.gov (United States)

    Dierdorf, Jens; Lohmar, Johannes; Hirt, Gerhard

    2017-10-01

    A comprehensive knowledge about the material flow stress is a key parameter for a reliable design of hot forming processes using Finite Element (FE) software codes. Due to the microstructure evolution caused by the interaction of hardening and softening phenomena that take place during hot forming operations, the material flow stress is influenced by strain rate and temperature. While transient strain rates and temperatures typically characterize the industrial forming processes, the flow curves used in FE simulations are normally determined at arbitrary constant temperatures and strain rates. To calculate the flow stress evolution in between the measured strain rates, FE programs use linear interpolation. Hence, the material relaxation behavior caused by the microstructure evolution during transient strain rates is not considered. Previous investigations by various authors have shown that for a rapid strain rate change by one order of magnitude significant deviations between measured flow stress and linear interpolation appear before the flow stress approximates the flow curve obtained at the new constant strain rate again. However as mentioned before, industrial forming processes are characterized by more or less smooth than instantaneous changes in strain rate. Therefore, in this study, changing strain rates with different linear slopes are investigated. For this purpose, isothermal cylinder compression tests of an industrial case hardening steel are conducted at elevated temperatures. The resulting flow stress is compared with the linear interpolation of the flow curves determined at constant strain rates. Additionally, the grain size evolution during the strain rate change is analyzed to better understand the microstructural changes. The current investigation shows that the slope of the strain rate increase significantly influences the deviation from the linear interpolation. This observation can be explained by the time dependent microstructure evolution

  1. Thermal Molding of Organic Thin-Film Transistor Arrays on Curved Surfaces.

    Science.gov (United States)

    Sakai, Masatoshi; Watanabe, Kento; Ishimine, Hiroto; Okada, Yugo; Yamauchi, Hiroshi; Sadamitsu, Yuichi; Kudo, Kazuhiro

    2017-12-01

    In this work, a thermal molding technique is proposed for the fabrication of plastic electronics on curved surfaces, enabling the preparation of plastic films with freely designed shapes. The induced strain distribution observed in poly(ethylene naphthalate) films when planar sheets were deformed into hemispherical surfaces clearly indicated that natural thermal contraction played an important role in the formation of the curved surface. A fingertip-shaped organic thin-film transistor array molded from a real human finger was fabricated, and slight deformation induced by touching an object was detected from the drain current response. This type of device will lead to the development of robot fingers equipped with a sensitive tactile sense for precision work such as palpation or surgery.

  2. Thermal Molding of Organic Thin-Film Transistor Arrays on Curved Surfaces

    Science.gov (United States)

    Sakai, Masatoshi; Watanabe, Kento; Ishimine, Hiroto; Okada, Yugo; Yamauchi, Hiroshi; Sadamitsu, Yuichi; Kudo, Kazuhiro

    2017-05-01

    In this work, a thermal molding technique is proposed for the fabrication of plastic electronics on curved surfaces, enabling the preparation of plastic films with freely designed shapes. The induced strain distribution observed in poly(ethylene naphthalate) films when planar sheets were deformed into hemispherical surfaces clearly indicated that natural thermal contraction played an important role in the formation of the curved surface. A fingertip-shaped organic thin-film transistor array molded from a real human finger was fabricated, and slight deformation induced by touching an object was detected from the drain current response. This type of device will lead to the development of robot fingers equipped with a sensitive tactile sense for precision work such as palpation or surgery.

  3. Work-hardening stages and deformation mechanism maps during tensile deformation of commercially pure titanium

    DEFF Research Database (Denmark)

    Becker, Hanka; Pantleon, Wolfgang

    2013-01-01

    Commercially pure titanium was tensile tested at different strain rates between 2.2×10−4s−1 and 6.7×10−1s−1 to characterize the strain rate dependence of plastic deformation and the dominating deformation mechanisms. From true stress-true plastic strain curves, three distinct work-hardening stages......¯2}〈101¯1〉 tensile twinning. Based on the microstructural findings and the strain rate sensitivity, deformation mechanism maps are constructed....

  4. Strain and temperature measurement

    International Nuclear Information System (INIS)

    Stewart, P.A.E.; Fowler, P.H.

    1988-01-01

    A method of non-invasively measuring strain and temperature of an object, substantially simultaneously, using neutrons of selected energy levels is described. A pulsed neutron source is made to emit thermal and epithermal neutrons in a collimated beam directed at the object. Temperature is monitored by observing the thermal Doppler broadening of resonances in the neutron transmission characteristic for the epithermal neutrons and strain is measured from observations made of changes to the thermal neutron diffraction pattern. The object may be a gas turbine blade or a thrust bearing. (author)

  5. Nickel--chromium strain gages for cryogenic stress analysis of superconducting structures in high magnetic fields

    International Nuclear Information System (INIS)

    Freynik, H.S. Jr.; Roach, D.R.; Deis, D.W.; Hirzel, D.G.

    1977-01-01

    Evaluation and calibration measurements were performed on commercial nickel-chromium metal-foil strain gages in a high-magnetic-field (12 T), liquid-helium (4.2 K) environment. The purpose was to fully characterize strain gages for use at cryogenic temperatures in high magnetic fields. In this study, the magnetoresistance of a number of strain gages was measured in three orthogonal directions at mechanical strain levels to 8900 μm/m. As a result, a unique calibration curve was defined for magnetoresistance strain errors that is independent of strain level and field direction to 12 T at 4.2 K. A current strain-gage application is the measurement of superconductor mechanical properties. These gages will soon be used in the stress analysis of superconducting fusion magnets during cooldown from ambient temperatures and during operation at 4.2 K with magnetic fields to 12 T

  6. A Note on Arithmetic Progressions on Elliptic Curves

    Science.gov (United States)

    Campbell, Garikai

    2003-02-01

    Andrew Bremner (Experiment. Math. 8 (1999), 409-413) has described a technique for producing infinite families of elliptic curves containing length 7 and length 8 arithmetic progressions. This note describes another way to produce infinite families of elliptic curves containing length 7 and length 8 arithmetic progressions. We illustrate how the technique articulated here gives an easy way to produce an elliptic curve containing a length 12 progression and an infinite family of elliptic curves containing a length 9 progression, with the caveat that these curves are not in Weierstrass form.

  7. Research on an innovative modification algorithm of NURBS curve interpolation

    Science.gov (United States)

    Zhang, Wanjun; Gao, Shanping; Cheng, Xiyan; Zhang, Feng

    2017-04-01

    in order to solve the problems of modification algorithm of NURBS curve interpolation, Such as interpolation time bigger, NURBS curve step error and chord error are not easy changed, and so on. A novel proposed a modification algorithm of NURBS curve interpolation. The algorithm has merits such as higher interpolation position accuracy, short processing time and so on. In this simulation, an open five-axis CNC platform based on SIEMENS 840D CNC system is developed for verifying the proposed modification algorithm of NURBS curve interpolation experimentally. The simulation results show that the algorithm is correct; it is consistent with a NURBS curve interpolation requirements.

  8. Fast Fr\\'echet Distance Between Curves With Long Edges

    OpenAIRE

    Gudmundsson, Joachim; Mirzanezhad, Majid; Mohades, Ali; Wenk, Carola

    2017-01-01

    Computing Fr\\'echet distance between two curves takes roughly quadratic time. In this paper, we show that for curves with long edges the Fr\\'echet distance computations become easier. Let $P$ and $Q$ be two polygonal curves in $\\mathbb{R}^d$ with $n$ and $m$ vertices, respectively. We prove four main results for the case when all edges of both curves are long compared to the Fr\\'echet distance between them: (1) a linear-time algorithm for deciding the Fr\\'echet distance between two curves, (2...

  9. Representative oxygen dissociation curve and equation for the chicken.

    Science.gov (United States)

    Boyd, R L; McDaniel, G R; Clark, C H

    1981-01-01

    Because of the considerable variability in the oxygen dissociation curves for chickens reported in the literature, the respiratory physiologist studying avian gas exchange is faced with the dilemma of which curve is representative for the chicken. In order to arrive at a representative curve, data from eight reported curves were compiled and adjusted to the same set of standard conditions of temperature (T), pH, and partial pressure of carbon dioxide (PCO2): T = 42 C, pH = 7.5 PCO2 = 40 torr. The mean PO2 STD (mean +/- SD) versus percent saturation of hemoglobin curve was then determined. The mean data were fitted to an equation representing the oxygen dissociation curve so that for any selected partial pressure of oxygen (PO2) the percent saturation (%SAT) of oxyhemoglobin may be computed. The P50 values for the mean literature and equation curves, respectively, were 47.4 +/- 9.8 and 45.3 Torr. The mean curve with its standard deviations provides a chicken oxygen dissociation curve representative of the literature data to which experimental data may be compared. The equation for the curve enables rapid referral to the representative curve to compute the %SAT, given the PO2 adjusted to the standard conditions.

  10. Compact Hilbert Curve Index Algorithm Based on Gray Code

    Directory of Open Access Journals (Sweden)

    CAO Xuefeng

    2016-12-01

    Full Text Available Hilbert curve has best clustering in various kinds of space filling curves, and has been used as an important tools in discrete global grid spatial index design field. But there are lots of redundancies in the standard Hilbert curve index when the data set has large differences between dimensions. In this paper, the construction features of Hilbert curve is analyzed based on Gray code, and then the compact Hilbert curve index algorithm is put forward, in which the redundancy problem has been avoided while Hilbert curve clustering preserved. Finally, experiment results shows that the compact Hilbert curve index outperforms the standard Hilbert index, their 1 computational complexity is nearly equivalent, but the real data set test shows the coding time and storage space decrease 40%, the speedup ratio of sorting speed is nearly 4.3.

  11. Pluto's light curve in 1933 1934

    Science.gov (United States)

    Schaefer, Bradley E.; Buie, Marc W.; Smith, Luke Timothy

    2008-10-01

    The Pluto-Charon system has complex photometric variations on all time scales; due to rotational modulations of dark markings across the surface, the changing orientation of the system as viewed from Earth, occultations and eclipses between Pluto and Charon, as well as the sublimation and condensation of frosts on the surface. The earliest useable light curve for Pluto is from 1953 to 1955 when Pluto was 35 AU from the Sun. Earlier data on Pluto has the potential to reveal properties of the surface at a greater heliocentric distance with nearly identical illumination and viewing geometry. We are reporting on a new accurate photographic light curve of Pluto for 1933-1934 when the heliocentric distance was 40 AU. We used 43 B-band and V-band images of Pluto on 32 plates taken on 15 nights from 19 March 1933 to 10 March 1934. Most of these plates were taken with the Mount Wilson 60″ and 100″ telescopes, but 7 of the plates (now at the Harvard College Observatory) were taken with the 12″ and 16″ Metcalf doublets at Oak Ridge. The plates were measured with an iris diaphragm photometer, which has an average one-sigma photometric error on these plates of 0.08 mag as measured by the repeatability of constant comparison stars. The modern B and V magnitudes for the comparison stars were measured with the Lowell Observatory Hall 1.1-m telescope. The magnitudes in the plate's photographic system were converted to the Johnson B- and V-system after correction with color terms, even though they are small in size. We find that the average B-band mean opposition magnitude of Pluto in 1933-1934 was 15.73±0.01, and we see a roughly sinusoidal modulation on the rotational period (6.38 days) with a peak-to-peak amplitude of 0.11±0.03 mag. With this, we show that Pluto darkened by 5% from 1933-1934 to 1953-1955. This darkening from 1933-1934 to 1953-1955 cannot be due to changing viewing geometry (as both epochs had identical sub-Earth latitudes), so our observations must

  12. Simple discs with flat roatation curves

    Science.gov (United States)

    Evans, N. W.; Collett, J. L.

    1993-09-01

    The aim of this paper is to understand why the squared axial ratio of the velocity ellipse, σphi_^2^/σ_R_^2^, of old disc stars in the Galaxy is less than 1/2. To this end, two infinitesimally thin steady-state axisymmetric discs with asymptotically flat circular velocity curves are presented. The first model - which we designate the Rybicki disc has surface density decaying inversely with radius. The second model is Freeman's exponential disc, which is immersed in the gravity field of the halo simulated by Mestel's potential. For both discs, we provide an infinite family of simple distribution functions, which form a sequence of increasing pressure support. In the Rybicki disc, the stellar streaming velocity increases outwards with radius, which typically causes σphi_^2^/σ_R_^2^ to be greater than 1/2. For our exponential disc distribution functions, the stellar streaming velocity declines outwards with radius, which typically causes σphi^2^/σ_R_^2^ to be less than 1/2. Our exponential disc distribution functions have the property that σ_R_^2^ decays only inversely with galactocentric radius R. If the diminution is faster, the ratio σphi_^2^/σ_R_^2^ rises above 1/2 at the Sun as the mean streaming velocity declines only in the inner disk. To investigate this, exponential discs with exponentially falling radial velocity dispersion are built. These are in conflict with the observations on the axial ratio, even allowing for a mismatch in the photometric and kinematic scalelengths. There are a number of possible resolutions of the contradiction: (1) the galactic disc is not in a steady state or is non-axisymmetric; (2) the circular velocity curve is locally declining; (3) the description of all stellar populations by a single distribution function is invalid; (4) the radial velocity dispersion does not drop off exponentially fast, but much more slowly; (5) the sampling of moving clusters and transient associations of stars creates a biased data set.

  13. Water Retention Curves of Opalinus Clay

    Energy Technology Data Exchange (ETDEWEB)

    Villar, M. V.; Romero, F. J.

    2012-11-01

    The water retention curve of Opalinus clay samples was determined under different conditions: total and matric suction, stress or no-stress conditions, wetting and drying paths. Through the fitting of these results to the van Genuchten expression the P parameter, related to the air entry value (AEV), was obtained. The AEV is the suction value above which air is able to enter the pores of the sample, and consequently, above which 2-phase flow can take place in the soil pore structure. The samples used in this research came from two different boreholes, BHT-1 and BHG-D1, but the behaviour of them did not depend on their location, what was probably due to the fact that both were drilled in the shay facies of the Opalinus clay. There was not a distinct difference between the results obtained under total or matric suctions. In the drying paths, both the water contents and the degrees of saturation tended to be higher when total suction was applied, however the reverse trend was observed for the water contents reached in wetting paths. As well, no clear difference was observed in the water retention curves obtained in odometers under matric and total suctions, what points to the osmotic component of suction in Opalinus clay not being significant. Overall, the water contents were lower and the degrees of saturation higher when suction was applied under vertical stress, what would indicate that the water retention capacity was lower under 8 MPa vertical stress than under free volume conditions. This vertical stress value is slightly higher than the maximum in situ stress. Also, the samples showed hysteresis according to the expected behaviour, i.e. the water contents for a given suction were higher during a drying path than during a wetting path. The P values obtained were between 6 and 34 MPa, and tended to be higher for the samples tested under stress, in drying paths and when total suction was used. The air entry value calculated from the mercury intrusion porosimetry

  14. D-Branes in Curved Space

    Energy Technology Data Exchange (ETDEWEB)

    McGreevy, John Austen; /Stanford U., Phys. Dept.

    2005-07-06

    This thesis is a study of D-branes in string compactifications. In this context, D-branes are relevant as an important component of the nonperturbative spectrum, as an incisive probe of these backgrounds, and as a natural stringy tool for localizing gauge interactions. In the first part of the thesis, we discuss half-BPS D-branes in compactifications of type II string theory on Calabi-Yau threefolds. The results we describe for these objects are pertinent both in their role as stringy brane-worlds, and in their role as solitonic objects. In particular, we determine couplings of these branes to the moduli determining the closed-string geometry, both perturbatively and non-perturbatively in the worldsheet expansion. We provide a local model for transitions in moduli space where the BPS spectrum jumps, and discuss the extension of mirror symmetry between Calabi-Yau manifolds to the case when D-branes are present. The next section is an interlude which provides some applications of D-branes to other curved backgrounds of string theory. In particular, we discuss a surprising phenomenon in which fundamental strings moving through background Ramond-Ramond fields dissolve into large spherical D3-branes. This mechanism is used to explain a previously-mysterious fact discovered via the AdS-CFT correspondence. Next, we make a connection between type IIA string vacua of the type discussed in the first section and M-theory compactifications on manifolds of G{sub 2} holonomy. Finally we discuss constructions of string vacua which do not have large radius limits. In the final part of the thesis, we develop techniques for studying the worldsheets of open strings ending on the curved D-branes studied in the first section. More precisely, we formulate a large class of massive two-dimensional gauge theories coupled to boundary matter, which flow in the infrared to the relevant boundary conformal field theories. Along with many other applications, these techniques are used to describe

  15. Strain relaxation near high-k/Si interface by post-deposition annealing

    International Nuclear Information System (INIS)

    Emoto, T.; Akimoto, K.; Yoshida, Y.; Ichimiya, A.; Nabatame, T.; Toriumi, A.

    2005-01-01

    We studied the effect of post-deposition annealing on a HfO 2 /Si interface of by extremely asymmetric X-ray diffraction. Comparing the rocking curves before annealing the sample with those of the annealed sample, it is found that an interfacial layer with a density of 3 g/cm 3 grows at the interface between the HfO 2 layer and the substrate during post-deposition annealing. The wavelength dependency of the integrated intensities of the rocking curve for the as-deposited sample fluctuated with the observation position. This fluctuation was suppressed by annealing. From these results we concluded that the strain introduced into the substrate becomes homogeneous by annealing. Moreover, a quantitative estimation of the strain by curve fitting reveals the existence of compressive strain under the HfO 2 layer

  16. Strain relaxation near high-k/Si interface by post-deposition annealing

    Energy Technology Data Exchange (ETDEWEB)

    Emoto, T. [Toyota National College of Technology, 2-1 Eisei-cho, Toyota, Aichi 471-8525 (Japan)]. E-mail: emoto@toyota-ct.ac.jp; Akimoto, K. [Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Yoshida, Y. [Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Ichimiya, A. [Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Nabatame, T. [MIRAI-ASET, AIST Tsukuba West, Tsukuba, Ibaraki 305-8569 (Japan); Toriumi, A. [MIRAI-ASRC, AIST Tsukuba Central 4, Tsukuba, Ibaraki 305-8562 (Japan); University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

    2005-05-15

    We studied the effect of post-deposition annealing on a HfO{sub 2}/Si interface of by extremely asymmetric X-ray diffraction. Comparing the rocking curves before annealing the sample with those of the annealed sample, it is found that an interfacial layer with a density of 3 g/cm{sup 3} grows at the interface between the HfO{sub 2} layer and the substrate during post-deposition annealing. The wavelength dependency of the integrated intensities of the rocking curve for the as-deposited sample fluctuated with the observation position. This fluctuation was suppressed by annealing. From these results we concluded that the strain introduced into the substrate becomes homogeneous by annealing. Moreover, a quantitative estimation of the strain by curve fitting reveals the existence of compressive strain under the HfO{sub 2} layer.

  17. Rational points, rational curves, and entire holomorphic curves on projective varieties

    CERN Document Server

    Gasbarri, Carlo; Roth, Mike; Tschinkel, Yuri

    2015-01-01

    This volume contains papers from the Short Thematic Program on Rational Points, Rational Curves, and Entire Holomorphic Curves and Algebraic Varieties, held from June 3-28, 2013, at the Centre de Recherches Mathématiques, Université de Montréal, Québec, Canada. The program was dedicated to the study of subtle interconnections between geometric and arithmetic properties of higher-dimensional algebraic varieties. The main areas of the program were, among others, proving density of rational points in Zariski or analytic topology on special varieties, understanding global geometric properties of rationally connected varieties, as well as connections between geometry and algebraic dynamics exploring new geometric techniques in Diophantine approximation.

  18. Environmental Kuznets Curve Hypothesis. A Survey

    International Nuclear Information System (INIS)

    Dinda, Soumyananda

    2004-01-01

    The Environmental Kuznets Curve (EKC) hypothesis postulates an inverted-U-shaped relationship between different pollutants and per capita income, i.e., environmental pressure increases up to a certain level as income goes up; after that, it decreases. An EKC actually reveals how a technically specified measurement of environmental quality changes as the fortunes of a country change. A sizeable literature on EKC has grown in recent period. The common point of all the studies is the assertion that the environmental quality deteriorates at the early stages of economic development/growth and subsequently improves at the later stages. In other words, environmental pressure increases faster than income at early stages of development and slows down relative to GDP growth at higher income levels. This paper reviews some theoretical developments and empirical studies dealing with EKC phenomenon. Possible explanations for this EKC are seen in (1) the progress of economic development, from clean agrarian economy to polluting industrial economy to clean service economy; (2) tendency of people with higher income having higher preference for environmental quality, etc. Evidence of the existence of the EKC has been questioned from several corners. Only some air quality indicators, especially local pollutants, show the evidence of an EKC. However, an EKC is empirically observed, till there is no agreement in the literature on the income level at which environmental degradation starts declining. This paper provides an overview of the EKC literature, background history, conceptual insights, policy and the conceptual and methodological critique

  19. Quantum fields in curved space-times

    International Nuclear Information System (INIS)

    Ashtekar, A.; Magnon, A.

    1975-01-01

    The problem of obtaining a quantum description of the (real) Klein-Gordon system in a given curved space-time is discussed. An algebraic approach is used. The *-algebra of quantum operators is constructed explicitly and the problem of finding its *-representation is reduced to that of selecting a suitable complex structure on the real vector space of the solutions of the (classical) Klein-Gordon equation. Since, in a static space-time, there already exists, a satisfactory quantum field theory, in this case one already knows what the 'correct' complex structure is. A physical characterization of this 'correct' complex structure is obtained. This characterization is used to extend quantum field theory to non-static space-times. Stationary space-times are considered first. In this case, the issue of extension is completely straightforward and the resulting theory is the natural generalization of the one in static space-times. General, non-stationary space-times are then considered. In this case the issue of extension is quite complicated and only a plausible extension is presented. Although the resulting framework is well-defined mathematically, the physical interpretation associated with it is rather unconventional. Merits and weaknesses of this framework are discussed. (author)

  20. Learning curve estimation techniques for nuclear industry

    International Nuclear Information System (INIS)

    Vaurio, Jussi K.

    1983-01-01

    Statistical techniques are developed to estimate the progress made by the nuclear industry in learning to prevent accidents. Learning curves are derived for accident occurrence rates based on actuarial data, predictions are made for the future, and compact analytical equations are obtained for the statistical accuracies of the estimates. Both maximum likelihood estimation and the method of moments are applied to obtain parameters for the learning models, and results are compared to each other and to earlier graphical and analytical results. An effective statistical test is also derived to assess the significance of trends. The models used associate learning directly to accidents, to the number of plants and to the cumulative number of operating years. Using as a data base nine core damage accidents in electricity-producing plants, it is estimated that the probability of a plant to have a serious flaw has decreased from 0.1 to 0.01 during the developmental phase of the nuclear industry. At the same time the frequency of accidents has decreased from 0.04 per reactor year to 0.0004 per reactor year

  1. A scrapbook of complex curve theory

    CERN Document Server

    Clemens, C Herbert

    1980-01-01

    This is a book of "impressions" of a journey through the theory of com­ plex algebraic curves. It is neither self-contained, balanced, nor particularly tightly organized. As with any notebook made on a journey, what appears is that which strikes the writer's fancy. Some topics appear because of their compelling intrinsic beauty. Others are left out because, for all their impor­ tance, the traveler found them boring or was too dull or lazy to give them their due. Looking back at the end of the journey, one can see that a common theme in fact does emerge, as is so often the case; that theme is the theory of theta functions. In fact very much of the material in the book is prepara­ tion for our study of the final topic, the so-called Schottky problem. More than once, in fact, we tear ourselves away from interesting topics leading elsewhere and return to our main route.

  2. Curved DNA: design, synthesis, and circulation

    International Nuclear Information System (INIS)

    Ulanovsky, L.; Bodner, M.; Trifonov, E.N.; Choder, M.

    1986-01-01

    Curved DNA molecules and unusually small circles have been obtained by ligation of synthetic 21-base precursors. The ligation resulted in the formation of double-stranded oligo(precursor)s possessing a strong 10.5-base-pair (bp) periodicity of the runs of adenines. Two-dimensional polyacrylamide gel electrophoresis of the ligation products showed two distinct families of spots: (i) noncircular oligo(precursor)s of 21 to 231 bp (1- to 11-mers) and (ii) four circles from 105 to 168 bp (eluted and analyzed by denaturing gel electrophoresis). The noncircular oligomers exhibited anomalously slow migration, as if they were as much as three times longer than they actually are. The amount of circular products peaked sharply at ≅ 126 bp, near which size the circles have been estimated to be nonconstrained both torsionally and in terms of bending. The nonconstrained circularization provides a technique for the direct measurement of the inherent curvature of DNA in solution. From the size of the circles, an estimate of 8.7 0 is obtained for the absolute value of the AA x TT wedge angle (roll and tilt combined)

  3. Tachyon Condensation on the Elliptic Curve

    CERN Document Server

    Govindarajan, S; Lerche, Wolfgang; Warner, Nicholas P

    2007-01-01

    We use the framework of matrix factorizations to study topological B-type D-branes on the cubic curve. Specifically, we elucidate how the brane RR charges are encoded in the matrix factors, by analyzing their structure in terms of sections of vector bundles in conjunction with equivariant R-symmetry. One particular advantage of matrix factorizations is that explicit moduli dependence is built in, thus giving us full control over the open-string moduli space. It allows one to study phenomena like discontinuous jumps of the cohomology over the moduli space, as well as formation of bound states at threshold. One interesting aspect is that certain gauge symmetries inherent to the matrix formulation lead to a non-trivial global structure of the moduli space. We also investigate topological tachyon condensation, which enables us to construct, in a systematic fashion, higher-dimensional matrix factorizations out of smaller ones; this amounts to obtaining branes with higher RR charges as composites of ones with minim...

  4. Matrix strings in weakly curved background fields

    International Nuclear Information System (INIS)

    Schiappa, Ricardo

    2001-01-01

    We investigate further the recent proposal for the form of the Matrix theory action in weak background fields. We perform DVV reduction to the multiple D0-brane action in order to find the Matrix string theory action for multiple fundamental strings in curved but weak NSNS and RR backgrounds. This matrix sigma model gives a definite prescription on how to deal with RR fields with an explicit spacetime dependence in Type II string theory. We do this both via the 9-11 flip and the chain of T and S dualities, and further check on their equivalence explicitly. In order to do so, we also discuss the implementation of S-duality in the operators of the 2-dimensional worldvolume supersymmetric gauge theory describing the Type IIB D-string. We compare the result to the known Green-Schwarz sigma model action (for one string), and use this comparison in order to discuss about possible, non-linear background curvature corrections to the Matrix string action (involving many strings), and therefore to the Matrix theory action. We illustrate the nonabelian character of our action with an example involving multiple fundamental strings in a nontrivial RR flux, where the strings are polarized into a noncommutative configuration. This corresponds to a dielectric type of effect on fundamental strings

  5. Leptogenesis from loop effects in curved spacetime

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, Jamie I.; Shore, Graham M. [Department of Physics, Swansea University,Singleton Park, Swansea, SA2 8PP (United Kingdom)

    2016-04-05

    We describe a new mechanism — radiatively-induced gravitational leptogenesis — for generating the matter-antimatter asymmetry of the Universe. We show how quantum loop effects in C and CP violating theories cause matter and antimatter to propagate differently in the presence of gravity, and prove this is forbidden in flat space by CPT and translation symmetry. This generates a curvature-dependent chemical potential for leptons, allowing a matter-antimatter asymmetry to be generated in thermal equilibrium in the early Universe. The time-dependent dynamics necessary for leptogenesis is provided by the interaction of the virtual self-energy cloud of the leptons with the expanding curved spacetime background, which violates the strong equivalence principle and allows a distinction between matter and antimatter. We show here how this mechanism is realised in a particular BSM theory, the see-saw model, where the quantum loops involve the heavy sterile neutrinos responsible for light neutrino masses. We demonstrate by explicit computation of the relevant two-loop Feynman diagrams how the size of the radiative corrections relevant for leptogenesis becomes enhanced by increasing the mass hierarchy of the sterile neutrinos, and show how the induced lepton asymmetry may be sufficiently large to play an important rôle in determining the baryon-to-photon ratio of the Universe.

  6. Learning curve for competency in flexible laryngoscopy.

    Science.gov (United States)

    Laeeq, Kulsoom; Pandian, Vinciya; Skinner, Margret; Masood, Hamid; Stewart, Charles M; Weatherly, Robert; Cummings, Charles W; Bhatti, Nasir I

    2010-10-01

    The purpose of our study was to identify the number of attempts required to attain competency in performing flexible laryngoscopy. Cross-sectional prospective study. Fifteen medical students were recruited to perform flexible laryngoscopy on a mannequin. Each participant was given unlimited time and attempts to perform the procedure until considered competent by the evaluator for two consecutive attempts. Three evaluators used a flexible laryngoscopy checklist to score performance on each step of the procedure. Time required to perform the procedure was recorded, as well as number of times the scope hit the mucosa. The criteria for attaining competence were achieving a minimum score of 3 out of 5 on all the items of the checklist and being deemed competent by the evaluator. A total of 105 flexible laryngoscopies were performed by 15 medical students. A mean of six attempts (range, 2-17) were necessary for a medical student to become competent in performing flexible laryngoscopy. An 80% probability of becoming competent was achieved with the 14th attempt. An inverse relationship was noted between the number of times the scope hit the mucosa and the probability of being competent. The time taken to perform the procedure decreased with increasing number of attempts. Our results suggest that it takes six attempts on average for a novice to become competent in performing flexible laryngoscopy. This finding has implications for residency programs because it indicates the learning curve can be overcome in the laboratory rather than with patients. Laryngoscope, 2010.

  7. Comparison of the acidifying activity of Lactococcus lactis subsp. lactis strains isolated from goat's milk and Valdeteja cheese.

    Science.gov (United States)

    Alonso-Calleja, C; Carballo, J; Capita, R; Bernardo, A; García-López, M L

    2002-01-01

    This work was carried out to study the acid production by Lactococcus lactis subsp. lactis strains isolated from goat's milk and goat cheese (Valdeteja variety) in order to select a suitable starter culture for industrial goat cheese manufacturing. The titrable acidity of 45 Lactococcus lactis subsp. lactis strains isolated from a home-made batch of Valdeteja cheese with excellent sensory characteristics was measured over a period of 18 h. The strains were divided into two groups depending on the acid production rate: 20 fast acid producer (F) strains and 25 slow acid producer (S) strains. The kinetic parameters (lag phase, maximum acid production rate and value of upper asymptote curve) of the acid production curves for F and S strains were significantly (P cheese manufacturing.

  8. Quantifying variant differences in DNA melting curves: Effects of length, melting rate, and curve overlay.

    Science.gov (United States)

    Li, M; Palais, R A; Zhou, L; Wittwer, C T

    2017-12-15

    High resolution DNA melting of PCR products is a simple technique for sequence variant detection and analysis. However, sensitivity and specificity vary and depend on many factors that continue to be defined. We introduce the area between normalized melting curves as a metric to quantify genotype discrimination. The effects of amplicon size (51-547 bp), melting rate (0.01-0.64 °C/s) and analysis method (curve shape by overlay vs absolute temperature differences) were qualitatively and quantitatively analyzed. To limit experimental variance, we studied a single nucleotide variant with identical predicted wild type and homozygous variant stabilities by nearest neighbor thermodynamic theory. Heterozygotes were easier to detect in smaller amplicons, at faster melting rates, and after curve overlay (superimposition), with some p-values overlay, PCR product size, and analysis method is complicated for homozygote genotype discrimination and is difficult to predict. Similar to temperature cycling in PCR, if the temperature control and temperature homogeneity of the solution are adequate, faster rates improve melting analysis, just like faster rates improve PCR. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Knitting Technologies And Tensile Properties Of A Novel Curved Flat-Knitted Three-Dimensional Spacer Fabrics

    Directory of Open Access Journals (Sweden)

    Li Xiaoying

    2015-09-01

    Full Text Available This paper introduces a knitting technique for making innovative curved three-dimensional (3D spacer fabrics by the computer flat-knitting machine. During manufacturing, a number of reinforcement yarns made of aramid fibres are inserted into 3D spacer fabrics along the weft direction to enhance the fabric tensile properties. Curved, flat-knitted 3D spacer fabrics with different angles (in the warp direction were also developed. Tensile tests were carried out in the weft and warp directions for the two spacer fabrics (with and without reinforcement yarns, and their stress–strain curves were compared. The results showed that the reinforcement yarns can reduce the fabric deformation and improve tensile stress and dimensional stability of 3D spacer fabrics. This research can help the further study of 3D spacer fabric when applied to composites.

  10. Standing sausage modes in curved coronal slabs

    Science.gov (United States)

    Pascoe, D. J.; Nakariakov, V. M.

    2016-09-01

    Context. Magnetohydrodynamic waveguides such as dense coronal loops can support standing modes. The ratios of the periods of oscillations for different longitudinal harmonics depend on the dispersive nature of the waveguide and so may be used as a seismological tool to determine coronal parameters. Aims: We extend models of standing sausage modes in low β coronal loops to include the effects of loop curvature. The behaviour of standing sausage modes in this geometry is used to explain the properties of observed oscillations that cannot be accounted for using straight loop models. Methods: We perform 2D numerical simulations of an oscillating coronal loop, modelled as a dense slab embedded in a potential magnetic field. The loop is field-aligned and so experiences expansion with height in addition to being curved. Standing sausage modes are excited by compressive perturbations of the loop and their properties are studied. Results: The spatial profiles of standing sausage modes are found to be modified by the expanding loop geometry typical for flaring loops and modelled by a potential magnetic field in our simulations. Longitudinal harmonics of order n > 1 have anti-nodes that are shifted towards the loop apex and the amplitude of anti-nodes near the loop apex is smaller than those near the loop footpoints. Conclusions: We find that the observation of standing sausage modes by the Nobeyama Radioheliograph in a flaring coronal loop on 12 January 2000 is consistent with interpretation in terms of the global mode (n = 1) and third harmonic (n = 3). This interpretation accounts for the period ratio and spatial structure of the observed oscillations.

  11. LAOS: The strain softening/strain hardening paradox

    NARCIS (Netherlands)

    Mermet-Guyennet, M.R.B.; de Castro, J.G.; Habibi, M.; Martzel, N.; Denn, M.M.; Bonn, D.

    2015-01-01

    Numerous materials, from biopolymers to filled rubbers, exhibit strain softening at high strain amplitudes during a strain sweep in oscillatory rheology: The modulus decreases with increasing deformation. On the other hand, if the nonlinear elastic response is analyzed within a single oscillation

  12. Ratchetting strain prediction

    International Nuclear Information System (INIS)

    Noban, Mohammad; Jahed, Hamid

    2007-01-01

    A time-efficient method for predicting ratchetting strain is proposed. The ratchetting strain at any cycle is determined by finding the ratchetting rate at only a few cycles. This determination is done by first defining the trajectory of the origin of stress in the deviatoric stress space and then incorporating this moving origin into a cyclic plasticity model. It is shown that at the beginning of the loading, the starting point of this trajectory coincides with the initial stress origin and approaches the mean stress, displaying a power-law relationship with the number of loading cycles. The method of obtaining this trajectory from a standard uniaxial asymmetric cyclic loading is presented. Ratchetting rates are calculated with the help of this trajectory and through the use of a constitutive cyclic plasticity model which incorporates deviatoric stresses and back stresses that are measured with respect to this moving frame. The proposed model is used to predict the ratchetting strain of two types of steels under single- and multi-step loadings. Results obtained agree well with the available experimental measurements

  13. Characterization of Multiaxial Stress-Strain Response of Tube Metal from Double-Sided Hydro-Bulging Test Based on Hosford's 1979 Yield Criterion

    Science.gov (United States)

    Cui, Xiao-Lei; Yang, Zhai-Ping; Wang, Xiao-Song

    2017-05-01

    To further explore the characterization of the multiaxial stress-strain responses of anisotropic tube metal from double-sided hydro-bulging tests, an analytical model for the equivalent stress and equivalent strain calculation was derived based on Hosford's 1979 yield criterion. Furthermore, thin-walled 5052-O aluminum alloy tubes were used to conduct the bulging experiment with an external pressure of 85 MPa. After the experimental data were substituted into the above analytical model, the Voce equation was used to fit the equivalent stress-strain relationship. It is concluded that the stress versus strain curves of the 5052-O tubes are strongly dependent on the loaded stress states, the adopted yield criteria, and the anisotropy coefficients. The external pressure of 85 MPa had little or no effect on the stress versus strain curves of the tubes, but the locations of the multiaxial stress versus strain curves were lower than that of the uniaxial stress versus strain curve. Moreover, the curve from Hosford's 1979 yield criterion not only had a higher saturation stress and material constant value than the curve from Mises and Hill's 1948 yield criteria but also had a dependence on the anisotropy coefficient.

  14. Elliptic Curved Component Macro-Programming and Its Application

    Science.gov (United States)

    Yang, Zhibo; Hu, Junchen; Li, Kaiqiang; Zhang, Shiyu; Liu, Aiju

    2017-10-01

    Most conventional numerical control systems do not have the function of noncircular curve interpolation instruction. Manual programming is extremely challenging, automatic programming by computer-aided manufacturing software is highly sophisticated, and processing parameters cannot be easily modified. Therefore, macro-programs, which possess powerful parametric programming, are applied for the processing of noncircular curved components. The values of arguments were determined using transfer and loop statements (IF and WHILE), and elliptic curved macro-programs were achieved using normal and parameter equations in this study. The elliptic curved components were fitted using micro-sized segments or arcs. The numerical control machining tests verified the validity and viability of the macro-programs, and elliptic curved components were processed. The results indicated that the elliptic curved components processed using macro-programs met the design requirements.

  15. Strain measurement based battery testing

    Science.gov (United States)

    Xu, Jeff Qiang; Steiber, Joe; Wall, Craig M.; Smith, Robert; Ng, Cheuk

    2017-05-23

    A method and system for strain-based estimation of the state of health of a battery, from an initial state to an aged state, is provided. A strain gauge is applied to the battery. A first strain measurement is performed on the battery, using the strain gauge, at a selected charge capacity of the battery and at the initial state of the battery. A second strain measurement is performed on the battery, using the strain gauge, at the selected charge capacity of the battery and at the aged state of the battery. The capacity degradation of the battery is estimated as the difference between the first and second strain measurements divided by the first strain measurement.

  16. Real parabolic vector bundles over a real curve

    Indian Academy of Sciences (India)

    by Seshadri [4] and their moduli studied in [2]. Here we consider real vector bundles over a real curve and define parabolic structures on real vector bundles. By a real curve, we mean a pair (X,σX ), where X is a compact Riemann surface and. σX is an anti-holomorphic involution on X. A real vector bundle over a real curve ...

  17. MATHEMATICAL METHODS TO DETERMINE THE INTERSECTION CURVES OF THE CYLINDERS

    Directory of Open Access Journals (Sweden)

    POPA Carmen

    2010-07-01

    Full Text Available The aim of this paper is to establish the intersection curves between cylinders, by using the Mathematica program. This thing can be obtained by introducing the curves equations, which are inferred, in Mathematica program. This paper take into discussion three right cylinders and another inclined to 45 degrees. The intersection curves can also be obtained by using the classical methods of the descriptive geometry.

  18. Integrable Flows for Starlike Curves in Centroaffine Space

    Directory of Open Access Journals (Sweden)

    Annalisa Calini

    2013-03-01

    Full Text Available We construct integrable hierarchies of flows for curves in centroaffine R^3 through a natural pre-symplectic structure on the space of closed unparametrized starlike curves. We show that the induced evolution equations for the differential invariants are closely connected with the Boussinesq hierarchy, and prove that the restricted hierarchy of flows on curves that project to conics in RP^2 induces the Kaup-Kuperschmidt hierarchy at the curvature level.

  19. Real parabolic vector bundles over a real curve

    Indian Academy of Sciences (India)

    Abstract. We define real parabolic structures on real vector bundles over a real curve. Let (X,σX ) be a real curve, and let S ⊂ X be a non-empty finite subset of X such that σX (S) = S. Let N ≥ 2 be an integer. We construct an N-fold cyclic cover p : Y → X in the category of real curves, ramified precisely over each point of S, ...

  20. Interpretation of photometric observations of R Coronae Borealis. Light curves

    International Nuclear Information System (INIS)

    Pugach, A.F.

    1990-01-01

    The calculations confirm the 'reptive hypothesis' of light variations of R CrB. The central point of the hypothesis is an assertion of infinite expansion of an elementary dust cloud. The calculations for different masses of the dust cloud provide a set of elementary light curves. Superposition of the curves yields a complex light curve. The comparison with the observed minima of 1972 has been performed

  1. Rational surfaces having only a finite number of exceptional curves

    International Nuclear Information System (INIS)

    Lahyane, M.

    2001-10-01

    We characterize the rational surfaces X which have a finite number of (-1)-curves under the assumption that - K X is nef (i.e., the intersection number of K X with any effective divisor on X is less than or equal to zero, where K X is a canonical divisor on X) and having self-intersection zero. A (-1)-curve is a smooth rational curve of self-intersection -1. (author)

  2. Construction of fractal surfaces by recurrent fractal interpolation curves

    International Nuclear Information System (INIS)

    Yun, Chol-hui; O, Hyong-chol; Choi, Hui-chol

    2014-01-01

    A method to construct fractal surfaces by recurrent fractal curves is provided. First we construct fractal interpolation curves using a recurrent iterated functions system (RIFS) with function scaling factors and estimate their box-counting dimension. Then we present a method of construction of wider class of fractal surfaces by fractal curves and Lipschitz functions and calculate the box-counting dimension of the constructed surfaces. Finally, we combine both methods to have more flexible constructions of fractal surfaces

  3. Elevated temperature stress strain behavior of beryllium powder product

    Energy Technology Data Exchange (ETDEWEB)

    Abeln, S.P.; Field, R. [Los Alamos National Lab., NM (United States); Mataya, M.C. [Safe Sites of Colorado, Golden, CO (United States)

    1995-09-01

    Several grades of beryllium powder product were tested under isothermal conditions in compression over a temperature range of room temperature to 1000 C and a strain rate range from 0.001 s{sup {minus}1} to 1 s{sup {minus}1}. Samples were compressed to a total strain of 1 (64% reduction in height). It is shown that all the grades are strain rate sensitive and that strain rate sensitivity increases with temperature. Yield points were exhibited by some grades up to a temperature of 500 C, and appeared to be primarily dependent on prior thermal history which determined the availability of mobile dislocations. Serrated flow in the form of stress drops was seen in all the materials tested and was most pronounced at 500 C. The appearance and magnitude of the stress drops were dependent on accumulated strain, strain rate, sample orientation, and composition. The flow stress and shape of the flow curves differed significantly from grade to grade due to variations in alloy content, the size and distribution of BeO particles, aging precipitates, and grain size. The ductile-brittle transition temperature (DBTT) was determined for each grade of material and shown to be dependent on composition and thermal treatment. Structure/property relationships are discussed using processing history, microscopy (light and transmission), and property data.

  4. Elevated temperature stress strain behavior of beryllium powder product

    International Nuclear Information System (INIS)

    Abeln, S.P.; Field, R.; Mataya, M.C.

    1995-01-01

    Several grades of beryllium powder product were tested under isothermal conditions in compression over a temperature range of room temperature to 1000 C and a strain rate range from 0.001 s -1 to 1 s -1 . Samples were compressed to a total strain of 1 (64% reduction in height). It is shown that all the grades are strain rate sensitive and that strain rate sensitivity increases with temperature. Yield points were exhibited by some grades up to a temperature of 500 C, and appeared to be primarily dependent on prior thermal history which determined the availability of mobile dislocations. Serrated flow in the form of stress drops was seen in all the materials tested and was most pronounced at 500 C. The appearance and magnitude of the stress drops were dependent on accumulated strain, strain rate, sample orientation, and composition. The flow stress and shape of the flow curves differed significantly from grade to grade due to variations in alloy content, the size and distribution of BeO particles, aging precipitates, and grain size. The ductile-brittle transition temperature (DBTT) was determined for each grade of material and shown to be dependent on composition and thermal treatment. Structure/property relationships are discussed using processing history, microscopy (light and transmission), and property data

  5. Studies on Drosophila radiosensitive strains

    International Nuclear Information System (INIS)

    Varentsova, E.P.; Zakharov, I.A.

    1976-01-01

    45 of radiosensitive strains of Drosophila melanogaster were isolated by Curly/Lobe technique after EMS treatment of Livadia population males. The lethality of non-Curly late larvae after gamma-irradiation (4000r) characterized radiosensitivity strains. Most of them exhibited higher frequency of the spontaneous dominant lethals (up to 69%). The males of 6 strains were semi-sterile. 5 of these strains exhibited higher frequency of X-chromosome non-disjunction

  6. Phillips and Wage Curves: Empirical Evidence from Bosnia and Herzegovina

    Directory of Open Access Journals (Sweden)

    Edo Omerčević

    2014-01-01

    Full Text Available This study is an empirical examination of the existence and characteristics of the Phillips curve and the wage curve in Bosnia and Herzegovina. The findings indicate that there is no evidence of the existence of the short-term Phillips curve. Instead, the data suggests that in the short-term an increase in inflation leads to an increase in unemployment. The estimated wage curves indicate that only increases in real payment increase employment. The conclusion of this study is that increases in inflation might have a negative short-term impact on the level of employment in Bosnia and Herzegovina.

  7. Unfired clay bricks – retention curves and liquid diffusivities

    DEFF Research Database (Denmark)

    Hansen, Kurt Kielsgaard; Peuhkuri, Ruut Hannele; Kristensen, A.

    2002-01-01

    This paper presents retention curves and liquid diffusivities of two different types of unfired clay bricks, both produced in Denmark on commercial basis. The retention curves are determined by use of pressure plate and pressure membrane apparatuses. The liquid diffusivity is calculated on the ba......This paper presents retention curves and liquid diffusivities of two different types of unfired clay bricks, both produced in Denmark on commercial basis. The retention curves are determined by use of pressure plate and pressure membrane apparatuses. The liquid diffusivity is calculated...

  8. Identification and "reverse engineering" of Pythagorean-hodograph curves

    OpenAIRE

    Farouki, RT; Giannelli, C; Sestini, A

    2015-01-01

    © 2015 Elsevier B.V. All rights reserved. Methods are developed to identify whether or not a given polynomial curve, specified by Bézier control points, is a Pythagorean-hodograph (PH) curve - and, if so, to reconstruct the internal algebraic structure that allows one to exploit the advantageous properties of PH curves. Two approaches to identification of PH curves are proposed. The first is based on the satisfaction of a system of algebraic constraints by the control-polygon legs, and the se...

  9. Maximum likelihood decay curve fits by the simplex method

    International Nuclear Information System (INIS)

    Gregorich, K.E.

    1991-01-01

    A multicomponent decay curve analysis technique has been developed and incorporated into the decay curve fitting computer code, MLDS (maximum likelihood decay by the simplex method). The fitting criteria are based on the maximum likelihood technique for decay curves made up of time binned events. The probabilities used in the likelihood functions are based on the Poisson distribution, so decay curves constructed from a small number of events are treated correctly. A simple utility is included which allows the use of discrete event times, rather than time-binned data, to make maximum use of the decay information. The search for the maximum in the multidimensional likelihood surface for multi-component fits is performed by the simplex method, which makes the success of the iterative fits extremely insensitive to the initial values of the fit parameters and eliminates the problems of divergence. The simplex method also avoids the problem of programming the partial derivatives of the decay curves with respect to all the variable parameters, which makes the implementation of new types of decay curves straightforward. Any of the decay curve parameters can be fixed or allowed to vary. Asymmetric error limits for each of the free parameters, which do not consider the covariance of the other free parameters, are determined. A procedure is presented for determining the error limits which contain the associated covariances. The curve fitting procedure in MLDS can easily be adapted for fits to other curves with any functional form. (orig.)

  10. The advanced geometry of plane curves and their applications

    CERN Document Server

    Zwikker, C

    2005-01-01

    ""Of chief interest to mathematicians, but physicists and others will be fascinated ... and intrigued by the fruitful use of non-Cartesian methods. Students ... should find the book stimulating."" - British Journal of Applied PhysicsThis study of many important curves, their geometrical properties, and their applications features material not customarily treated in texts on synthetic or analytic Euclidean geometry. Its wide coverage, which includes both algebraic and transcendental curves, extends to unusual properties of familiar curves along with the nature of lesser known curves.Informativ

  11. Detecting corner points from digital curves

    International Nuclear Information System (INIS)

    Sarfraz, M.

    2011-01-01

    Corners in digital images give important clues for shape representation, recognition, and analysis. Since dominant information regarding shape is usually available at the corners, they provide important features for various real life applications in the disciplines like computer vision, pattern recognition, computer graphics. Corners are the robust features in the sense that they provide important information regarding objects under translation, rotation and scale change. They are also important from the view point of understanding human perception of objects. They play crucial role in decomposing or describing the digital curves. They are also used in scale space theory, image representation, stereo vision, motion tracking, image matching, building mosaics and font designing systems. If the corner points are identified properly, a shape can be represented in an efficient and compact way with sufficient accuracy. Corner detection schemes, based on their applications, can be broadly divided into two categories: binary (suitable for binary images) and gray level (suitable for gray level images). Corner detection approaches for binary images usually involve segmenting the image into regions and extracting boundaries from those regions that contain them. The techniques for gray level images can be categorized into two classes: (a) Template based and (b) gradient based. The template based techniques utilize correlation between a sub-image and a template of a given angle. A corner point is selected by finding the maximum of the correlation output. Gradient based techniques require computing curvature of an edge that passes through a neighborhood in a gray level image. Many corner detection algorithms have been proposed in the literature which can be broadly divided into two parts. One is to detect corner points from grayscale images and other relates to boundary based corner detection. This contribution mainly deals with techniques adopted for later approach

  12. Utilizing Photogrammetry and Strain Gage Measurement to Characterize Pressurization of Inflatable Modules

    Science.gov (United States)

    Mohammed, Anil

    2011-01-01

    This paper focuses on integrating a large hatch penetration into inflatable modules of various constructions. This paper also compares load predictions with test measurements. The strain was measured by utilizing photogrammetric methods and strain gages mounted to select clevises that interface with the structural webbings. Bench testing showed good correlation between strain data collected from an extensometer and photogrammetric measurements, even when the material transitioned from the low load to high load strain region of the curve. The full-scale torus design module showed mixed results as well in the lower load and high strain regions. After thorough analysis of photogrammetric measurements, strain gage measurements, and predicted load, the photogrammetric measurements seem to be off by a factor of two.

  13. Micromechanical modeling of damage in periodic composites using strain gradient plasticity

    DEFF Research Database (Denmark)

    Azizi, Reza

    2012-01-01

    model for the fiber–matrix interface. For the micro structure, free energy holds both elastic strains and plastic strain gradients. Due to the gradient theory, higher order boundary conditions must be considered. A unit cell with a circular elastic fiber is studied by the numerical finite element cell......Damage evolution at the fiber matrix interface in Metal Matrix Composites (MMCs) is studied using strain gradient theory of plasticity. The study includes the rate independent formulation of energetic strain gradient plasticity for the matrix, purely elastic model for the fiber and cohesive zone...... model under simple shear and transverse uniaxial tension using plane strain and periodic boundary conditions. The result of the overall response curve, effective plastic strain, effective stress and higher order stress distributions are shown. The effect of the material length scale, maximum stress...

  14. Development of a Charpy master curve-based embrittlement trend curve

    International Nuclear Information System (INIS)

    Erikson, M.

    2011-01-01

    Under the current U.S. surveillance programs, the Charpy V-notch energy (CVE), yield strength, and tensile strength are measured (all as a function of test temperature) at various times during the operational life of the reactor vessel. Conventionally, the CVE vs. temperature data are fit using a hyperbolic tangent (tanh) function to determine the temperature at which the mean CVE is equal to 30 ft-lbs (41J). This index temperature, which is designated T30 or T41J, is used to track irradiation damage. Recently an alternative strategy for fitting the CVE vs. temperature data was proposed in which a single CVE vs. temperature relationship appears to well represent the behavior of a very wide variety of ferritic steels for temperatures at and below fracture mode transition. It was demonstrated that when upper shelf data are excluded from a fit of Charpy V-notch energy (CVE) vs. temperature a single exponential function is found that well represents the transition temperature behavior of ferritic steels. The findings suggest that a reanalysis of already tested Charpy surveillance specimens can provide the basis for development of an embrittlement trend curve that is less influenced by the biases that arise from the tanh curve fitting method. Recently, a program was initiated with a goal of using the Charpy MC transition data fit to define a reference temperature, to use instead of the traditionally defined tanh-based T30/T41J reference temperature, in development of an embrittlement trend curve. The existing USLWR database was mined for datasets with sufficient data points within the transition temperature region for use in defining a TCVE reference temperature. These values were then used to define ΔTCVE data with irradiation. This data, along with chemistry, temperature, flux and fluence information, was used to develop the embrittlement trend curve presented herein. Predictions of embrittlement behavior made using this ETC were then compared to predictions made

  15. [Reference curves for assessing the physical growth of male Wistar rats].

    Science.gov (United States)

    Cossio-Bolaños, Marco; Gómez Campos, Rossana; Vargas Vitoria, Rodrigo; Hochmuller Fogaça, Rosalvo Tadeu; de Arruda, Miguel

    2013-11-01

    Wistar rats are one of the most popular strains routinely used for research in the laboratory to serve as an important research tool, so it requires strict control of variables such as age, sex and body weight, and Thus to extrapolate the results to the human model. To develop reference curves for assessing the physical growth of male Wistar rats according to chronological age and somatic maturation from a non-invasive. The subjects studied were 731 male Wistar rats transversely. We assessed age, body weight and body surface. LMS method was used to construct percentile curves based on weight and somatic maturation. The proposed physical growth curves are used to track the physical growth and nutritional status diagnosis of male Wistar rats. Budgets by cutting points are: P3, P10, P25, P50, P75, P90 and P97. The results suggest that scientists from different areas can use such references, in order to extrapolate somatic growth phases of the laboratory rat and the human model is a non-invasive alternative to assess growth and nutritional status. Copyright AULA MEDICA EDICIONES 2013. Published by AULA MEDICA. All rights reserved.

  16. Polynuclear Aromatic Hydrocarbons with Curved Surfaces: Buckyballs

    Energy Technology Data Exchange (ETDEWEB)

    Sygula, Andrzej [Mississippi State Univ., Mississippi State, MS (United States)

    2016-08-15

    The discovery of a new allotropic form of elemental carbon – the fullerenes – and subsequently other novel forms of elemental carbon with pyramidalized surfaces, most notably single-walled and multi-walled carbon nanotubes, introduced a novel structural motif to the polycyclic aromatic hydrocarbons (PAHs) with nonplanar surfaces. Our research program supported by BES DOE grant DE-FG02-04ER15514 has dealt with the synthesis, structural studies, and chemistry of the novel curved-surface PAHs with carbon frameworks structurally related to fullerenes. They are referred to as “buckybowls”. We prepared several new buckybowls and, even more importantly, developed the efficient, gram-scale synthetic methodologies for the preparation of small buckybowls, most notably corannulene (C20H10) and its derivatives. In addition, the employment of the corannulene-based synthons previously developed in our laboratory led to a number of highly nonplanar molecular architectures with two or more corannulene subunits with a potential for the applications as novel materials in separation sciences, nanoelectronics, photovoltaics and catalysis. In collaboration with Professor Angelici (Iowa State) we prepared and characterized several transition metal complexes of corannulene, providing the first structural characterization of η6 metal complexes of buckybowls by a single crystal X-ray diffraction. In addition to the definitive structural characterization of the complexes we demonstrated that the (η6-C6Me6)Ru2+ unit in some relatively stable complexes activate the corannulene ligand to react with proper nucleophiles suggesting that such complexex may be used in catalysis. (Section C). We have explored the efficiency of the dispersion-based interactions of curved-surface conjugated carbon networks by high-level computational models. We showed that the curvature of such networks does not reduce the van der Waals attractions as compared to the planar systems of similar size. We than

  17. Problems associated with use of the logarithmic equivalent strain in high pressure torsion

    International Nuclear Information System (INIS)

    Jonas, J J; Aranas, C Jr

    2014-01-01

    The logarithmic 'equivalent' strain is frequently recommended for description of the experimental flow curves determined in high pressure torsion (HPT) tests. Some experimental results determined at -196 and 190 °C on a 2024 aluminum alloy are plotted using both the von Mises and logarithmic equivalent strains. Three types of problems associated with use of the latter are described. The first involves the lack of work conjugacy between the logarithmic and shear stress/shear strain curves, a topic that has been discussed earlier. The second concerns the problems associated with testing at constant logarithmic strain rate, a feature of particular importance when the material is rate sensitive. The third type of problem involves the 'history dependence' of this measure in that the incremental logarithmic strain depends on whether the prior strain accumulated in the sample is known or not. This is a difficulty that does not affect use of the von Mises equivalent strain. For these reasons, it is concluded that the qualifier 'equivalent' should not be used when the logarithmic strain is employed to describe HPT results

  18. BILAM: a composite laminate failure-analysis code using bilinear stress-strain approximations

    Energy Technology Data Exchange (ETDEWEB)

    McLaughlin, P.V. Jr.; Dasgupta, A.; Chun, Y.W.

    1980-10-01

    The BILAM code which uses constant strain laminate analysis to generate in-plane load/deformation or stress/strain history of composite laminates to the point of laminate failure is described. The program uses bilinear stress-strain curves to model layer stress-strain behavior. Composite laminates are used for flywheels. The use of this computer code will help to develop data on the behavior of fiber composite materials which can be used by flywheel designers. In this program the stress-strain curves are modelled by assuming linear response in axial tension while using bilinear approximations (2 linear segments) for stress-strain response to axial compressive, transverse tensile, transverse compressive and axial shear loadings. It should be noted that the program attempts to empirically simulate the effects of the phenomena which cause nonlinear stress-strain behavior, instead of mathematically modelling the micromechanics involved. This code, therefore, performs a bilinear laminate analysis, and, in conjunction with several user-defined failure interaction criteria, is designed to provide sequential information on all layer failures up to and including the first fiber failure. The modus operandi is described. Code BILAM can be used to: predict the load-deformation/stress-strain behavior of a composite laminate subjected to a given combination of in-plane loads, and make analytical predictions of laminate strength.

  19. A Constitutive Model for Strain-Controlled Strength Degradation of Rockmasses (SDR)

    Science.gov (United States)

    Kalos, A.; Kavvadas, M.

    2017-11-01

    The paper describes a continuum, rate-independent, incremental plasticity constitutive model applicable in weak rocks and heavily fractured rockmasses, where mechanical behaviour is controlled by rockmass strength rather than structural features (discontinuities). The model describes rockmass structure by a generalised Hoek-Brown Structure Envelope (SE) in the stress space. Stress paths inside the SE are nonlinear and irreversible to better simulate behaviour at strains up to peak strength and under stress reversals. Stress paths on the SE have user-controlled volume dilatancy (gradually reducing to zero at large shear strains) and can model post-peak strain softening of brittle rockmasses via a structure degradation (damage) mechanism triggered by accumulated plastic shear strains. As the SE may strain harden with plastic strains, ductile behaviour can also be modelled. The model was implemented in the Finite Element Code Simulia ABAQUS and was applied in plane strain (2D) excavation of a cylindrical cavity (tunnel) to predict convergence-confinement curves. It is shown that small-strain nonlinearity, variable volume dilatancy and post-peak hardening/softening strongly affect the predicted curves, resulting in corresponding differences of lining pressures in real tunnel excavations.

  20. Linear dose response curves in fungi and tradescantia

    International Nuclear Information System (INIS)

    Unrau, P.

    1999-07-01

    Tradescantia Clone 02 data suggests that linear non-threshold dose responses are expected to the lowest doses and dose rates of low linear energy transfer (LET) radiation. This is likely to be true for other living organisms even though Clone 02 is radiation sensitive. It is concluded that Clone 02 is partially defective in the RAD 6 pathway for the repair of DNA interstrand cross-links (ISCL) and other loss of coding damage (LCD), based on its cross sensitivities to EMS and ionizing radiation. Tradescantia Clone 02 data showing linear non-threshold induction of somatic genetic events in part reflects the repair deficiency of this Clone. More DNA damage is repaired by recombinational mechanisms in Clone 02 than would occur in a wild-type strain. Two important classes of DNA lesions are induced by ionizing radiation in DNA - double strand breaks (DSB) which are repaired by recombination mechanisms, and loss of coding information damage (LCD), which is repaired by error prone mechanisms but may also be a substrate for recombinational repair. Based on data from yeast, there are two different repair pathways which deal with these differing lesions with different somatic genetic consequences. From yeast, yield cross sections can be derived and applied to DNA damage and repair in Tradescantia. For Clone 02, per lesion, more visible genetic events are scored than in wild-type strains. In a radiation-derived sub-clone, Clone 0106, which is more variable than Clone 02, even more events occur per lesion. This derivative clone, plus breeding experiments, indicate that Clone 02 is heterozygous, or a 'carrier' for a mutant version of a gene in the Tradescantia RAD 6 repair pathway. Clone 02 is, therefore, much like a Fanconi's anemia carrier in a human population, while the Clone 0106 derivative is much like a homozygous Fanconi's anemia patient, with respect to its response to ionizing radiation damage. Two anomalies in its dose response curves for 'pink' loss of