DEFF Research Database (Denmark)
Pedersen, Preben Terndrup; Jensen, Jørgen Juncher
2009-01-01
-induced loads are evaluated for specific operational profiles. Non-linearity in the wave bending moment is modeled using results derived from a second-order strip theory and water entry solutions for wedge type sections. Hence, bow flare slamming is accounted for through a momentum type of approach. The...... stochastic properties of this non-linear response are calculated through a monotonic Hermite transformation. In addition, the impulse loading due to e.g. bottom slamming or a rapid change in bow flare is included using a modal expansion in the two lowest vertical vibration modes. These whipping vibrations...
International Nuclear Information System (INIS)
In this paper the large amplitude and non-linear vibration of a string is considered. The initial tension, lateral vibration amplitude, diameter and the modulus of elasticity of the string have main effects on its natural frequencies. Increasing the lateral vibration amplitude makes the assumption of constant initial tension invalid. In this case, therefore, it is impossible to use the classical equation of string with small amplitude transverse motion assumption. On the other hand, by increasing the string diameter, the bending moment effect will increase dramatically, and acts as an impressive restoring moment. Considering the effects of the bending moments, the nonlinear equation governing the large amplitude transverse vibration of a string is derived. The time dependent portion of the governing equation has the from of Duff ing equation is solved using the perturbation theory. The results of the analysis are shown in appropriate graphs, and the natural frequencies of the string due to the non-linear factors are compared with the natural frequencies of the linear vibration os a string without bending moment effects
Bolted flanged connections with longitudinal bending moments: Experimental results
International Nuclear Information System (INIS)
Flanges in piping systems and on tall vertical pressure vessels such as columns or fractionators, are often subjected to external, longitudinal bending moments of considerable magnitude. In piping systems, such bending moments are usually caused by thermal expansion. On pressure vessel flanges, external bending moments are often the result of wind or seismic loadings. In the ASME Code, only Section III, the Nuclear Power Plant Code, Subsections NB, NC, and ND, contain design rules for external bending moments on flanges. In Subsections NB, NC, and ND, an empirical formula is given, expressing a longitudinal bending moment in bolted flanged connections in terms of an equivalent internal pressure to be added to the design pressure of the flange. Other sections of the ASME Code, in particular Section VIII, Divisions 1 and 2, also the ASME-ANSI Piping Codes, do not contain rules for such external, longitudinal bending moments. In previous papers by the same authors, it was shown that a single empirical expression to convert external bending moments to intemal pressure, cannot include the differences between the geometries of flanges of various sizes. An attempt was also made to analyse the stresses in the flange-bolt assembly due to extemal bending moments and to compare flange thicknesses thus obtained with thicknesses required using the equivalent design pressure, specified in Subsections NB, NC, and ND. The present paper reports the findings of a series of experiments on a pair of 100 mm, Class 10 (4 inch, Class 150) pipe flanges which were subjected to various combinations of intemal pressure and extemal longitudinal bending. Measured values are compared with a proposed analytic design method and with results using the empirical formula of the ASME Code, Section III
Plastic collapse loads in shape-imperfect pipe bends under in-plane opening bending moment
International Nuclear Information System (INIS)
The combined effect of ovality and thinning/thickening on collapse load of pipe bends under in-plane opening bending moment was investigated using finite element limit analysis considering large geometric change effect. The material is assumed to be elastic-perfectly plastic. Twice-elastic-slope method is used to obtain collapse moment from moment–rotation curves drawn for each bend. Variation of thickness due to thinning in the cross section of pipe bend produces negligible effect on collapse load. The effect of ovality is significant except for pipe ratio 20 with λ = 0.5. A new closed-form solution is proposed to determine collapse moment of pipe bends with ovality and it is validated with existing experimental data. -- Highlights: • Collapse loads for shape-imperfect pipe bends is determined. • Ovality and thinning are the shape imperfections considered. • Finite element limit analysis uses large geometry change effects. • Twice-elastic-slope method was used to obtain plastic loads. • Ovality needs to be considered to determine collapse load while thinning produces negligible effect
Nonlinear Bending Stiffness of Plates Clamped by Bolted Joints under Bending Moment
Naruse, Tomohiro; Shibutani, Yoji
Equivalent stiffness of plates clamped by bolted joints for designing should be evaluated according to not only the strength of bolted joints but also the deformation and vibration characteristics of the structures. When the applied external axial load or the bending moment is sufficiently small, the contact surfaces of the bolted joint are stuck together, and thus both the bolt and the clamped plates deform linearly. Although the sophisticated VDI 2230 code gives the appropriate stiffness of clamped plates for the infinitesimal deformation, the stiffness may vary nonlinearly with increasing the loading because of changing the contact state. Therefore, the present paper focuses on the nonlinear behaviour of the bending stiffness of clamped plates by using Finite Element (FE) analyses, taking the contact condition on bearing surfaces and between the plates into account. The FE models of the plates with thicknesses of 3.2, 4.5, 6.0 and 9.0 mm tightened with M8, 10, 12 and 16 bolts were constructed. The relation between bending moment and bending compliance of clamped plates is found to be categorized into three regions, namely, (i) constant compliance with fully stuck contact surfaces, (ii) transition showing the nonlinear compliance, and (iii) constant compliance with one-side contact surfaces. The mechanical models for these three regions are proposed and compared with FEM solutions. The prediction on the bounds of three regions is in a fairly good agreement except the case with smaller bolts and thicker plates.
Improving Bending Moment Measurements on Wind Turbine Blades
Energy Technology Data Exchange (ETDEWEB)
Post, Nathan L.
2016-03-15
Full-scale fatigue testing of wind turbine blades is conducted using resonance test techniques where the blade plus additional masses is excited at its first resonance frequency to achieve the target loading amplitude. Because there is not a direct relationship between the force applied by an actuator and the bending moment, the blade is instrumented with strain gauges that are calibrated under static loading conditions to determine the sensitivity or relationship between strain and applied moment. Then, during dynamic loading the applied moment is calculated using the strain response of the structure. A similar procedure is also used in the field to measure in-service loads on turbine blades. Because wind turbine blades are complex twisted structures and the deflections are large, there is often significant cross-talk coupling in the sensitivity of strain gauges placed on the structure. Recent work has shown that a sensitivity matrix with nonzero cross terms must be employed to find constant results when a blade is subjected to both flap and lead-lag loading. However, even under controlled laboratory conditions, potential for errors of 3 percent or more in the measured moment exist when using the typical cross-talk matrix approach due to neglecting the influence of large deformations and torsion. This is particularly critical when considering a biaxial load as would be applied on the turbine or during a biaxial fatigue test. This presentation describes these results demonstrating errors made when performing current loads measurement practices on wind turbine blades in the lab and evaluating potential improvements using enhanced cross-talk matrix approaches and calibration procedures.
Bending Moment Decrease of Reinforced Concrete Beam Supported by Additional CFRP
Directory of Open Access Journals (Sweden)
Mykolas Daugevičius
2011-04-01
Full Text Available The calculation method of reinforced concrete beam with additional CFRP composite is proposed in this article. This method estimates tangential angular concrete deformations in tensioned beam layers between steel and bonded carbon fiber reinforced polymer. The horizontal slip of CFRP composite reduce beam bending moment capacity. An additional coefficient to reduce CFRP resultant force is necessary for better precision of bending moment capacity. Also, various calculation methods of bending moment capacity are considered. Article in Lithuanian
Energy Technology Data Exchange (ETDEWEB)
Guo, Y.; Keller, J.; LaCava, W.
2012-09-01
This computational work investigates planetary gear load sharing of three-mount suspension wind turbine gearboxes. A three dimensional multibody dynamic model is established, including gravity, bending moments, fluctuating mesh stiffness, nonlinear tooth contact, and bearing clearance. A flexible main shaft, planetary carrier, housing, and gear shafts are modeled using reduced degrees-of-freedom through modal compensation. This drivetrain model is validated against the experimental data of Gearbox Reliability Collaborative for gearbox internal loads. Planet load sharing is a combined effect of gravity, bending moment, bearing clearance, and input torque. Influences of each of these parameters and their combined effects on the resulting planet load sharing are investigated. Bending moments and gravity induce fundamental excitations in the rotating carrier frame, which can increase gearbox internal loads and disturb load sharing. Clearance in carrier bearings reduces the bearing load carrying capacity and thus the bending moment from the rotor can be transmitted into gear meshes. With bearing clearance, the bending moment can cause tooth micropitting and can induce planet bearing fatigue, leading to reduced gearbox life. Planet bearings are susceptible to skidding at low input torque.
Axial forces and bending moments in the loaded rabbit tibia in vivo
Directory of Open Access Journals (Sweden)
Reifenrath Janin
2012-03-01
Full Text Available Abstract Background Different animal models are used as fracture models in orthopaedic research prior to implant use in humans, although biomechanical forces can differ to a great extend between species due to variable anatomic conditions, particularly with regard to the gait. The rabbit is an often used fracture model, but biomechanical data are very rare. The objective of the present study was to measure axial forces, bending moments, and bending axis directly in the rabbit tibia in vivo. The following hypothesis was tested: Axial forces and bending moments in the mid-diaphysis of rabbit tibia differ from other experimental animals or indirectly calculated data. Methods A minifixateur system with 4 force sensors was developed and attached to rabbit tibia (n = 4, which were subsequently ostectomised. Axial forces, bending moments and bending angles were calculated telemetrically during weight bearing in motion between 6 and 42 days post operation. Results Highest single values were 201% body weight [% bw] for axial forces and 409% bw cm for bending moments. Whereas there was a continous decrease in axial forces over time after day 10 (P = 0.03 on day 15, a decrease in bending moments was inconsistent (P = 0.03 on day 27. High values for bending moments were frequently, but not consistently, associated with high values for axial forces. Conclusion Axial forces in rabbit tibia exceeded axial forces in sheep, and differed from indirectly calculated data. The rabbit is an appropriate fracture model because axial loads and bending moments in rabbit tibia were more closely to human conditions than in sheep tibia as an animal model.
Limit load of elbows under combined internal pressure and in-plane bending moment
International Nuclear Information System (INIS)
Elastic-plastic finite element analysis has been carried out to evaluate collapse moments of six elbows with elbow factors varying from 0.24 to 0.6. Collapse moment is obtained by twice elastic slope method from the moment v/s end-rotation curve. The effect of internal pressure on in-plane closing / opening collapse moment is studied. For various elbow factors and level of internal pressure, total 60 and 54 cases are analysed for closing and opening mode of bending moment respectively. Based on these results, two closed-form equations are proposed to evaluate the collapse moments of elbows under combined internal pressure and in-plane closing and opening bending moment. (orig.)
EFFECT OF ADHESIVE TYPE ON THE BENDING MOMENT CAPACITY OF MITER FRAME CORNER JOINTS
Directory of Open Access Journals (Sweden)
Suat Altun
2010-05-01
Full Text Available The bending moment capacity was studied under the diagonal tensile and compression loadings of miter corner joints with dovetail fitting in frames made with medium density fiberboard (MDF. The influence of the type of adhesive in the joints with dovetail fitting on bending moment capacity under diagonal tensile and compression loading were considered, and the joints without adhesive were compared. A total of 80 each miter frame corner joint specimens with dovetail fitting were made. Polyvinyl acetate (PVAc, polyurethane (PU, and cyanoacrylate (CA adhesives were used, and 20 specimens were prepared without adhesive (WA with dovetail fitting. MDF was used as a frame material, as in normal practice. The specimens were subjected to diagonal tensile and compression loadings in accordance with ASTM-D 143-94. The data were analyzed statistically. The highest bending moment capacity under diagonal tensile loading (46.09 Nm was obtained in the specimens bonded with CA adhesive and the highest bending moment capacity under diagonal compression loading (72.04 Nm was obtained in the specimens glued with PVAc adhesive. Other than this, since there is no difference between these and the unbonded joints, the PU adhesive was not effective in increasing the bending moment capacity under diagonal tensile loading, and the PU and CA adhesives were not effective in increasing the bending moment capacity under diagonal compression loadings.
Stress intensity factors under combined bending and torsion moments
Institute of Scientific and Technical Information of China (English)
Al Emran ISMAIL; Ahmad Kamal ARIFFIN; Shahrum ABDULLAH; Mariyam Jameelah GHAZALI; Mohammed ABDULRAZZAQ; Ruslizam DAUD
2012-01-01
This paper discusses stress intensity factor (SIF) calculations for surface cracks in round bars subjected to combined torsion and bending loadings.Different crack aspect ratios,a/b,ranging from 0.0 to 1.2 and relative crack depths,a/D,ranging from 0.1 to 0.6 were considered.Since the loading was non-symmetrical for torsion loadings,a whole finite element model was constructed.Then,the individual and combined bending and torsion loadings were remotely applied to the model.The equivalent SIF method,F* EQ,was then used explicitly to combine the individual SIFs from the bending and torsion loadings.A comparison was then carried out with the combined SIE F* FE,obtained using the finite element analysis (FEA) under similar loadings.It was found that the equivalent SIF method successfully predicted the combined SIF for Mode (I).However,discrepancies between the results determined from the different approaches occurred when FⅢ was involved.It was also noted that the predicted F* FE using FEA was higher than the F* EQ predicted through the equivalent SIF method due to the difference in crack face interactions.
Axial forces and bending moments in the loaded rabbit tibia in vivo
Reifenrath Janin; Gottschalk Daniel; Angrisani Nina; Besdo Silke; Meyer-Lindenberg Andrea
2012-01-01
Abstract Background Different animal models are used as fracture models in orthopaedic research prior to implant use in humans, although biomechanical forces can differ to a great extend between species due to variable anatomic conditions, particularly with regard to the gait. The rabbit is an often used fracture model, but biomechanical data are very rare. The objective of the present study was to measure axial forces, bending moments, and bending axis directly in the rabbit tibia in vivo. T...
The Effect of Dowel and Minifix on the Bending Moment in the Cabinet-type Furniture
Çetin Yerlikaya, Nurdan
2013-01-01
In this study, the effects of the dowel and minifix on the bending moment of L-type corner joints in the cabinet-type furniture investigated. For this purpose, melamine-coated fiberboard (MCF) is used in the tension and compression experiments. Dowel and minifix as fasteners are used. “2 minifix”, “2 minifix + 1 dowel”, “2 minifix + 2 dowel”, and “2 dowel” as joint type are used. According to experimental results, the highest bending moment value was obtained in the “2 minifix + 2 dowel” join...
Mechanical Model of Steel-concrete Composite Joint under Sagging Bending Moment
Pisarek, Zdzisław
2012-06-01
In buildings with steel-concrete composite floors, joints are designed to transmit mainly hogging bending moment. In case of the large horizontal loads due to wind, earthquake or accidental events, sagging bending moments in a joint can also occur. Additionally, large deformations of the structure cause tying and prying effects. In the paper, a mechanical model based on "component method" for evaluation of characteristics of the composite joint is presented. The influence of tying and prying actions on distribution of the internal forces in a joint is also analyzed. The procedure for calculation of the characteristics of the composite joint with bolted endplate connection is elaborated too.
DEFF Research Database (Denmark)
Valvo, Paolo S.; Sørensen, Bent F.; Toftegaard, Helmuth Langmaack
2015-01-01
A theoretical model of the double cantilever beam tests with bending moments (DCB-UBM) is presented. The specimen is modelled as the assemblage of two laminated beams connected by a cohesive interface. It is assumed that the traction-separation laws – i.e. the relationships between the interfacial...
Stress intensity factors of three parallel edge cracks under bending moments
International Nuclear Information System (INIS)
This paper reports the study of stress intensity factors (SIF) of three edge cracks in a finite plate under bending moments. The goal of this paper was to analyze the three edge crack interactions under such loading. Several studies can be found in literature discussing on mode I SIF. However, most of these studies obtained the SIFs using tensile force. Lack of SIF reported discussing on the SIFs obtained under bending moments. ANSYS finite element program was used to develop the finite element model where singular elements were used to model the cracks. Different crack geometries and parameters were utilized in order to characterize the SIFs. According to the present results, crack geometries played a significant role in determining the SIFs and consequently induced the crack interaction mechanisms
Plastic limit load of cylindrical shells with cutouts subject to pure bending moment
International Nuclear Information System (INIS)
In this paper, the results of limit analyses of thin-walled cylindrical shells with a circular hole under the action of a pure bending moment are presented in dimensionless form for a wide range of geometric parameters. Analytical estimation of lower bound limit load is carried out using the feasible sequential quadratic programming (FSQP) technique. The finite element calculations of limit load consist of elastic-plastic and lower and upper bound predictions by elastic compensation methods. A testing device was made to perform experiments to obtain limit bending moment of cylinders with circular openings. The analytical and finite element calculations are compared with experimental results and their correlation is discussed. The finite element calculation results were found to be in good agreement with lower bound estimations by the nonlinear mathematical programming (FSQP) method and the formula proposed by Shu
Sutherland, H. J.
The load spectrum unposed upon a horizontal-axis wind turbine blade is typically decomposed into two primary bending moments; flap and edgewise bending. The critical fatigue loads (stress cycles) imposed on the blade may not be on one of these axes, especially if die two bending loads are in-phase with one another. To quantify the correlation of these two bending moments and determine the impact of this correlation on off-axis fatigue loads, an extensive data set for a typical wind turbine blade is examined. The results are compared using their respective cycle count matrices. These results illustrate that the harmonic components of die principal bending stresses are correlated, and that the random components are not. The analysis techniques described in the paper provide the turbine designer with a spectral technique for combining primary bending spectra into off-axis fatigue loads.
Directory of Open Access Journals (Sweden)
Maher Kakish
2007-01-01
Full Text Available The distribution of bending moments in T-beam deck slab varies from one T-beam to another. The design of T-beams should be based on the actual bending moments each beam is subjected to for the purpose of achieving economy especially in bridge deck slab, extended over big area. The saving in some cases is substantial due to reducing the quantities of steel and concrete.
International Nuclear Information System (INIS)
The safety assessment of pipes with local wall thinning defects is highly important in engineering. Most attention has been paid on the safety assessment of pipe with single local wall thinning defect, while the studies about multiple local wall thinning defects are not nearly enough. However, the interaction of multiple local wall thinning defects in some conditions is great, and may have a great impact on the safety assessment. In the present standard API 579/ASME FFS, the safety assessment of pipes with multiple local wall thinning defects is given, while as well as the influence of load condition, the influences of arrangement and relative depth of defects are ignored, which may influence the safety assessment considerably. In this paper, the influence of the interaction between multiple local wall thinning defects on the remaining strength of pipes at different arrangements and depths of defects under different load conditions (pressure, tension-bending moment and compression-bending moment) are studied. A quantified index is defined to describe the interaction between defects quantitatively. For different arrangements and relative depths of defects, based on a limit value 0.05 of the quantified index of the interaction between defects, a relatively systematic safety assessment of pipes with multiple local wall thinning defects under different load conditions has been proposed.
The Effect of Composite Patches on the Failure of Adhesively-Bonded Joints Under Bending Moment
Akpinar, Salih
2013-12-01
In this study, it was aimed to compare mechanical behavior of double-strap joints with aluminum (AA2024-T3) or 16-ply laminate of carbon/epoxy composite (T300/934) patches of different orientation angles at their overlap area subjected to bending moment. For this purpose, AA2024-T3 aluminum was used as adherend, while the adhesive was a two-part paste (DP 460). Six different types of joint samples were subjected to bending moment. The effect of patch material on failure load and stress distribution was examined experimentally and numerically. In the numerical analysis, the composite patches were assumed to behave linearly elastic, while adherend and adhesive layers were assumed to be nonlinear. It was found that the data obtained from 3-D finite element analysis were coherent with experimental results. Meanwhile, experiments showed that fiber orientation angles of the patches markedly affected the failure load of joints, failure mode and stress distributions appeared in adhesive and composite.
Homogenization of long fiber reinforced composites including fiber bending effects
Poulios, Konstantinos; Niordson, Christian F.
2016-09-01
This paper presents a homogenization method, which accounts for intrinsic size effects related to the fiber diameter in long fiber reinforced composite materials with two independent constitutive models for the matrix and fiber materials. A new choice of internal kinematic variables allows to maintain the kinematics of the two material phases independent from the assumed constitutive models, so that stress-deformation relationships, can be expressed in the framework of hyper-elasticity and hyper-elastoplasticity for the fiber and the matrix materials respectively. The bending stiffness of the reinforcing fibers is captured by higher order strain terms, resulting in an accurate representation of the micro-mechanical behavior of the composite. Numerical examples show that the accuracy of the proposed model is very close to a non-homogenized finite-element model with an explicit discretization of the matrix and the fibers.
Homogenization of long fiber reinforced composites including fiber bending effects
DEFF Research Database (Denmark)
Poulios, Konstantinos; Niordson, Christian Frithiof
2016-01-01
This paper presents a homogenization method, which accounts for intrinsic size effects related to the fiber diameter in long fiber reinforced composite materials with two independent constitutive models for the matrix and fiber materials. A new choice of internal kinematic variables allows to...... maintain the kinematics of the two material phases independent from the assumed constitutive models, so that stress-deformation relationships, can be expressed in the framework of hyper-elasticity and hyper-elastoplasticity for the fiber and the matrix materials respectively. The bending stiffness of the...... reinforcing fibers is captured by higher order strain terms, resulting in an accurate representation of the micro-mechanical behavior of the composite. Numerical examples show that the accuracy of the proposed model is very close to a non-homogenized finite-element model with an explicit discretization of the...
Institute of Scientific and Technical Information of China (English)
齐向阳; 高卫国; 刘腾; 张大卫
2015-01-01
The motion track of belt spindle is important for the radial error of belt spindle. An analytical modeling method for the motion track of belt spindle under the combined effects of bending moment-torque-thermal deforma-tion is proposed in this paper. Three running phases of belt spindle have been analyzed and modeled:the start-up phase with leaping change due to the change in force and bending moment, the accelerating phase with axis deflection, and the constant speed phase with axis regression because of the combined effects of bending moment-torque-thermal de-formation. The simulation and test were completed on the belt spindle of SKVM850 machine tool, which illustrates the variation law of the radial error of belt spindle during the whole running phases.
Extreme value prediction of the wave-induced vertical bending moment in large container ships
DEFF Research Database (Denmark)
Andersen, Ingrid Marie Vincent; Jensen, Jørgen Juncher
Container ships of today are becoming increasingly larger. The increased ship size implies lower natural hull frequencies which influence the hull girder response in waves. The large bow and stern flare of container ships make them vulnerable to whipping-induced loads, and whipping loads may...... increase the extreme hull girder response significantly. Focus in the present paper is on the influence of the hull girder flexibility on the extreme response amidships, namely the wave-induced vertical bending moment (VBM) in hogging, and the prediction of the extreme value of the same. The analysis in...... proper threshold level as well as the statistical correlation between clustered peaks influence the extreme value prediction and are taken into consideration in the present paper....
Low cycle fatigue of pressurized pipes with circumferential flaws under cyclic bending moment
International Nuclear Information System (INIS)
Pipes of 706 mm inner diameter, 47 mm wall thickness and about 5,000 mm in length were provided with circumferential surface cracks and loaded by internal pressure of 15 MPa whilst being simultaneously subjected to an alternating external bending moment. Usually a load ratio R of -1 (Mmin/Mmax), in one case R = 0.1, was applied. The pipes were fabricated of two types of ferritic steel: one, grade 20 MnMoNi 5 5, with a high upper shelf impact energy of about 200 J and one, MnMoNiV-special melt, with a low upper shelf impact energy of about 60 J. Deformation and crack growth in the wall thickness and circumferential direction were determined and compared with calculated values. 9 refs., 13 figs
Directory of Open Access Journals (Sweden)
Mehmet AKTAŞ
2001-03-01
Full Text Available In this study; the stress intensity factor was computed for a cylindrical object that was under effect of bending moment, axial stress and internal pressure. In order to make the calculations easy, the stress intensity factor was calculated individually for bending moment, axial stress and internal pressure. Then, the result were superimposed to have a final stress intensity factor for the concerned object. The calculated stress intensity factor is known as Mode I, which corresponds to "opening mode". Furthermore, it was assumed that there were some initial radial cracks around the center line for a given object and the amount of change on the stress intensity factor was discussed.
International Nuclear Information System (INIS)
Plastic limit load of elbows with local thinned area (LTA) under combined internal pressure and in-plane closing bending moment has been studied by finite element analysis (FEA) and experiments. The results of FEA and experiments show that, with different LTA, the variation of the limit load of elbows to the internal pressure is different. When a/b≤0.313, the limit moment of elbows always decreases with the increasing of the internal pressure. When a/b>0.313, the limit moment of elbows increases with the increasing of the internal pressure and then decreases with the increasing of the internal pressure. By fitting the results of FEA, the safety assessment figure for elbows under combined internal pressure and in-plane closing bending moment is drawn. The safety assessment method using this figure is applicable for the engineer problems. (authors)
Toderan, Catalin; Richir, Thomas; Caprace, Jean-David; Rigo, Philippe
2006-01-01
This paper presents a method to asses hull girder ultimate bending moment distribution, taking into account parameters uncertainty. This method is a part of a research activity carried out at University of Liege. The method is able to compute four statistical moments of ultimate strength distribution: average, standard deviation, skewness and kurtosis. Geometry parameters, material parameters and initial imperfections (initial deflections and residual stresses) are considered a...
Energy Technology Data Exchange (ETDEWEB)
Mang, F.; Herion, S.; Bucak, O. [Univ. of Karlsruhe (Germany)
1994-12-31
This paper presents first results of calculations according to the finite element method for uniplanar K-joints with gap. The investigations cover thin-walled rectangular hollow sections of commonly used dimensions and manufacture. The employed finite element model has been optimized and checked carefully in a research program sponsored by the Deutsche Forschungsgemeinschaft DFG (Research foundation of German government) dealing with multiplanar K-joints with gap. Compared to previous investigations, the influence of axial load, in-plane bending moments (IPB) and out-of-plane bending moments (OPB) are considered separately. With these models, parametric studies have been carried out to make statements on the strain concentration factors SNCF in terms of the geometric parameters {beta} = b{sub 1}/b{sub 0}; {tau} = t{sub 1}/t{sub 0} and gap g. As far as possible, graphs are given.
Energy Technology Data Exchange (ETDEWEB)
Herion, S.; Mang, F. [Univ. of Karlsruhe (Germany)
1994-12-31
This paper presents the most significant results of a comprehensive parametric study on multiplanar K-joints. In this study, which is part of a pH. D. work, the influence of axial load, in-plane bending moments (IPB) and out-of-plane bending moments (OPB) are considered separately. For each type of loading, symmetric load vectors have been assumed and the most unfavorable assumption has been investigated. On this basis and in dependence of the geometric parameters {beta} = b{sub 1}/b{sub 0}, {tau} = t{sub 1}/t{sub 0}, 2{gamma} = b{sub 1}/t{sub 0}, SNCF diagrams and formulae for the design of multiplanar K-joints with gap made of RHS are given.
Institute of Scientific and Technical Information of China (English)
Jiang Haijun; Cao Shenggen; Zhang Yun; Wang Chen
2016-01-01
The distribution of front abutment pressure is closely related to the force, deformation and energy distri-bution of hard roof before periodic weighting. So it is necessary to carry out research on the relationship between them. According to front abutment pressure distribution feature, using the location of peak front abutment pressure as the dividing point, coal seam is divided into two parts along the direction of min-ing:the yield zone that is the area between the faceline and the point where the maximum front abut-ment pressure occurs, and the elastic zone that is the part before the point of peak front abutment pressure. The proposed mechanical model of unit width hard roof at the panel center before periodic weighting consists of five parts including the yield zone. All parameters of the deflection equations for each of the five parts that satisfy the continuity conditions and natural boundary conditions are obtained by using the Matlab software. The continuous curves of front abutment pressure, deflection, bending moment and bending strain energy density distribution of hard roof are obtained by iterative approxima-tion method, and the relationship between the yield zone width and the above curves are analyzed in detailed.
International Nuclear Information System (INIS)
No experimental data exist within open literature, to the best knowledge of the author, for determining shakedown boundaries of 90° back-to-back pipe bends. Ninety degree back-to-back pipe bends are extensively utilized within piping networks of nuclear submarines and modern turbofan aero-engines where space limitation is considered a paramount concern. In the current research, the 90° back-to-back pipe bend setup analyzed is subjected to a spectrum of steady internal pressures and cyclic in-plane bending moments. A previously developed direct non-cyclic simplified technique for determining elastic shakedown limit loads is utilized to generate the elastic shakedown boundary of the analyzed structure. The simplified technique outcomes showed excellent correlation with the results of full elastic–plastic cyclic loading finite element simulations. - Highlights: • No shakedown experimental data exist for 90° back-to-back pipe bends. • A non-cyclic technique is utilized to generate the elastic shakedown boundary. • The non-cyclic technique succeeded in generating the structure's Bree diagram. • The non-cyclic technique correlated well with full cyclic loading FE simulations
International Nuclear Information System (INIS)
The pipe bends and elbows are regarded as critical components in piping systems of nuclear power plants because they are incorporated into piping systems to allow modification of the isometric routing and more importantly pipe bends are usually incorporated to reduce anchor reaction forces. Also, the pipe bends and elbows are capable of absorbing considerably large thermal expansion and seismic movement through the energy dissipation as a result of local plastic deformation so that they maintain the integrity of piping system under transiently loading conditions. However, significant care must be taken to avoid their collapse moment. Therefore, it is important to accurately assess the safety margin for a collapse of pipe bends and elbows under various operating conditions
International Nuclear Information System (INIS)
Highlights: → Behavior of cracked elbows with part-through crack at intrados under bending moment is studied. → Some part of crack always opens and some part gets closed irrespective of mode of applied moment. → Fraction of the crack that opens basically decides the weakening effect of the cracked elbow. → Results will be useful for fracture studies and limit load estimation especially for LBB. - Abstract: This paper presents the behavior of part-through circumferential crack at intrados in elbows under in-plane bending moment. This is based on detailed non-linear (both material and geometric) finite element analysis performed on various sizes of elbows (generally used in piping industry), having different crack sizes. It is observed that some part of the crack always opens and some part gets closed irrespective of the mode of applied bending moment (opening/closing). The fraction of the crack that opens basically decides the weakening effect of the cracked elbow. It is observed that there is a threshold value of crack length and crack depth, before which no crack opening is observed under opening mode. Also as elbow becomes thinner, the threshold value of above two parameters increases. Quite interestingly, the part of crack which closes in opening mode opens under closing mode. The above mentioned study on the behavior of crack will be useful for fracture studies and limit load estimation especially when leak before break concept is to be employed.
International Nuclear Information System (INIS)
Highlights: ► A simplified plastic collapse assessment procedure for pipe bends with a local thin area is proposed. ► Conditions under combined internal pressure and external in-plane bending moment are considered. ► The procedure is using the p–M diagram method (pressure ratio and external bending moment ratio). ► The p–M diagram is derived from the reference stresses based on the Tresca theory. ► The plastic collapse loads are ascertained by results of the full scale testing with pipe bends and FEA. - Abstract: Pipe bends are common elements in piping systems such as power or process piping, and local thinning typically occurs on pipe bends due to erosion and/or corrosion. Therefore, it is important to establish the plastic collapse condition for pipe bends having a local thin area (LTA) under combined internal pressure and external bending moment. In this paper, a simplified plastic collapse assessment procedure in the p–M (internal pressure ratio and external bending moment ratio) diagram method for pipe bends with a local thin area simultaneously subjected to internal pressure, p, and external in-plane bending moment, M, due to earthquake, etc., is proposed, which is based on the reference stresses derived from the Tresca theory under a three axes condition. The plastic collapse loads derived from the proposed p–M diagram method are ascertained by comparing with the results of experimental testing with full-scale pipe bends and those of FEA for the same sized pipe bends with an LTA having various dimensions as well.
DEFF Research Database (Denmark)
Sørensen, Bent F.; Jørgensen, K.; Jacobsen, T.K.;
2004-01-01
A mixed mode specimen is proposed for fracture mechanics characterisation of adhesive joints, laminates and multilayers. The specimen is a double cantilever beam specimen loaded with uneven bending moments at the two free beams. By varying the ratiobetween the two applied moments, the full mode...... mixity range from pure mode I to pure mode II can be generated for the same specimen geometry. The specimen allows stable crack growth. In case of large scale crack bridging, mixed mode cohesive laws can beobtained by a J integral based approach. As an example, fracture of adhesive joints between two...
Subrahmanyam, K. B.; Kaza, K. R. V.; Brown, G. V.; Lawrence, C.
1986-01-01
The coupled bending-bending-torsional equations of dynamic motion of rotating, linearly pretwisted blades are derived including large precone, second degree geometric nonlinearities and Coriolis effects. The equations are solved by the Galerkin method and a linear perturbation technique. Accuracy of the present method is verified by comparisons of predicted frequencies and steady state deflections with those from MSC/NASTRAN and from experiments. Parametric results are generated to establish where inclusion of only the second degree geometric nonlinearities is adequate. The nonlinear terms causing torsional divergence in thin blades are identified. The effects of Coriolis terms and several other structurally nonlinear terms are studied, and their relative importance is examined.
Directory of Open Access Journals (Sweden)
Seçil ERİM
1998-03-01
Full Text Available In this study, a beam subjected to pure bending with a circular hole on its transverse axis, is analyzed by the Finite Element Method. The hole is shifted to various locations along the transverse axis and two different materials, namely isotropic (steel and orthotropic (graphite-epoxy, are used as beam material. Stress distribution and stress concentration factors around the hole are determined for each case. In order to establish the effect of fiber reinforcing angle on the stress distribution, the examination is repeated at various reinforcing angles between 0° and 90° for graphite-epoxy. Denoting the distance between the longitudinal axis and the center of the hole as b, the value of the critical hole diameter which leads to the maximum theoretical bending moment is determined by using the Finite Element Method. Furthermore, the critical distance b which will create the maximum theoretical bending moment for a constant hole diameter of 10 mm, is calculated for steel and each reinforcing angle of the composite beam.
International Nuclear Information System (INIS)
The combined effect of ovality and variable wall thickness on collapse load of pipe bends under in-plane opening bending moment with internal pressure was investigated using finite element limit analysis considering large geometric change effect. The material was assumed to be elastic–perfectly plastic. The collapse moments were obtained from moment-rotation curves drawn for each bend using twice-elastic-slope method. Thickening/thinning effect on collapse load is very minimal and can be neglected. The effect of ovality is significant with the reduction of collapse load by a maximum of 39.1% for the maximum internal pressure and ovality considered. Based on the finite element results, a mathematical expression is proposed to determine collapse load of the pipe bends with ovality and this equation has been verified with experimental collapse loads. - Highlights: • Shape imperfect pipe bends subject to in-plane bending and internal pressure is studied. • Ovality produces significant effect on collapse moments of pipe bends while thinning has negligible effect. • Based on the FE results, a mathematical expression is proposed to determine collapse load of the pipe bends with ovality
Plane strain finite element analysis of sheet forming operations including bending effects
Cho, Uk Youn
1993-01-01
An improved finite element method suitable for the plane-strain analysis of sheet metal forming operations is presented. The method incorporates a computationally efficient shell model and a consistent frictional contact algorithm through an implicit updated Lagrangian formulation. The workpiece material model is rigid-viscoplastic with a choice of power law hardening and plastic normal anisotropy and is capable of modeling a wide variety of sheet metals. A simplified nonlinear incremental shell theory is employed along with an optional reduced integration through the thickness for computational efficiency, while retaining the advantages of the kinematic model containing the bending effects. Complex tool geometry can be handled by discrete data points, by primitives (lines and arcs), or by analytical functions. The capabilities of the method are demonstrated through verification problems and comparisons with experimental data, benchmark results, and published data for several practical problems of the sheet metal forming industry. The problems include stretching and/or deep drawing operations, simulation of automobile panel section, and brake bending operation. As an independent investigation from the first portion of the dissertation, measured data from a set of simple bending experiments of two types of aluminum are presented and analyzed. Generated data from the experiments include strain histories (loading and unloading), spring back information (spring back angle and strains), and friction coefficients. As a by-product, a simple way of estimating the friction coefficient (Coulomb's law) during a bending operation is proposed and demonstrated.
Institute of Scientific and Technical Information of China (English)
Jin Wencheng; Zhou Xiaoyong; Li Na
2008-01-01
A numerical model is developed in this paper to calculate the bending moments of flexural members through integration in 3D solid finite element analyses according to the nonlinear constitutive model of concrete and the elastoplastic constitutive model of steel, utilizing the stress condition of the cross-section, considering the destruction characteristic of reinforced concrete members, and based on the plane cross-section assumption. The results of this model give good agreement with those of the classical method. Consequently, we can also deduce the corresponding numerical expression for eccentrically loaded members according to the analysis method.
International Nuclear Information System (INIS)
The advent of Leak-Before-Break (LBB) concept has replaced the traditional design basis event of Double Ended Guillotine Break (DEGB) in the design of primary heat transport (PHT) piping. The use of LBB concept requires postulation of largest credible cracks at highly stressed locations and demonstration of its stability under the maximum credible loading conditions. Stress analysis of PHT piping in nuclear power plants shows that the highly stressed piping components are normally elbows and branch tees. This necessitates detailed fracture mechanics evaluation of piping connections by computing Stress Intensity Factor (SIF) and/or J-integral. Simple analytical solutions for evaluation of SIF and J-integral for cracks in straight pipes are readily available in literature. However, the same type of solutions for elbows and tees are limited in open literature. In the present work, a database is generated to evaluate SIF for throughwall circumferential and longitudinal cracks under combined internal pressure and bending moment. Different parameters to characterise a cracked elbow are pipe factor (h), pipe bore radius to thickness ratio (r/t) and crack length. Another parameter (σ) is used to consider the relative magnitude of stresses due to internal pressure and remote bending moment. The database has been used to derive closed form expressions to evaluate SIF for elbow with cracks in terms of the aforementioned parameters. (author). 8 refs., 12 figs., 3 tabs
International Nuclear Information System (INIS)
The advent of the leak-before-break (LBB) concept has widely replaced the traditional design basis event of a double-ended guillotine break (DEGB) in the design of primary heat transport (PHT) piping. Stress analysis of PHT piping in nuclear power plants shows that the highly stressed piping components are normally elbows and branch tees. This necessitates detailed fracture mechanics evaluation of such piping connections by computing their stress intensity factors (SIF) and/or J-integral. Simple analytical solutions for evaluation of the SIF and J-integral for cracks in straight pipes are readily available in the literature. However the same type of solution for elbows and tees is limited in the open literature. In the present work a database is generated to evaluate the SIF for throughwall circumferential and longitudinal cracks under combined internal pressure and bending moment. (author)
DEFF Research Database (Denmark)
Andersen, Ingrid Marie Vincent; Jensen, Jørgen Juncher
2012-01-01
the ship. The theory takes into account non-linear radiation forces (memory effects) through the use of a set of higher order differential equations. The non-linear hydrostatic restoring forces and non-linear Froude-Krylov forces are determined accurately at the instantaneous position of the ship in...... global hull girder loads as consequence of the increased hull flexibility must be considered. This is especially so as the rules of the classification societies do not explicitly account for the effect of hull flexibility on the global loads. In the present paper an analysis has been carried out for the...... 9,400 TEU container ship used as case-ship in the EU project TULCS (Tools for Ultra Large Container Ships). A non-linear time-domain strip theory is used for the hydrodynamic analysis of the vertical bending moment amidships in sagging and hogging conditions for a flexible and a rigid modelling of...
Elasto-plastic bending of cracked plates, including the effects of crack closure. Ph.D. Thesis
Jones, D. P.
1972-01-01
A capability for solving elasto-plastic plate bending problems is developed using assumptions consistent with Kirchhoff plate theory. Both bending and extensional modes of deformation are admitted with the two modes becoming coupled as yielding proceeds. Equilibrium solutions are obtained numerically by determination of the stationary point of a functional which is analogous to the potential strain energy. The stationary value of the functional for each load increment is efficiently obtained through use of the conjugate gradient. This technique is applied to the problem of a large centrally through cracked plate subject to remote circular bending. Comparison is drawn between two cases of the bending problem. The first neglects the possibility of crack face interference with bending, and the second includes a kinematic prohibition against the crack face from passing through the symmetry plane. Results are reported which isolate the effects of elastoplastic flow and crack closure.
International Nuclear Information System (INIS)
Piping elbows under in-plane bending moment are vulnerable to cracking. The crack initiates at the surface and eventually reaches through the thickness and may lead to failure. The structural integrity assessment requires knowledge of the limit load. Limit load solutions for elbows with through-wall crack configurations are available in the open literature. But solutions for surface crack are not available. This paper presents a closed form expression for the plastic collapse moment (PCM) of 90 deg., long radius elbows with circumferential surface cracks at the intrados, under in-plane bending moment. The expression is derived, based on the results of non-linear (geometric and material) FE analyses covering a wide range of geometries and crack sizes. These plastic collapse moments evaluated herein will help in structural integrity assessment. - Highlights: → Piping elbows under in-plane bending moment are vulnerable to cracking. → Structural integrity assessment requires limit load solution. → presents a closed form expression for PCM of cracked elbow. → Results will help in structural integrity assessment of cracked elbows.
Akshay P. Gholkar; H. S. JADHAV
2014-01-01
This paper presents the flexural behaviour of basalt fiber reinforced polymer (BFRP) strengthened reinforced concrete (RC) beams. For flexural strengthening of reinforced concrete beams, total twenty-two beams were cast and tested over an effective span of 900 mm up to failure of the beam under two-point loading. The beams were designed as under-reinforced beams. The beams were bonded with BFRP sheets in single layer and double layers in the bending moment region at the bottom...
Faber, G S; Chang, C C; Kingma, I; Dennerlein, J T; van Dieën, J H
2016-04-11
Inertial motion capture (IMC) systems have become increasingly popular for ambulatory movement analysis. However, few studies have attempted to use these measurement techniques to estimate kinetic variables, such as joint moments and ground reaction forces (GRFs). Therefore, we investigated the performance of a full-body ambulatory IMC system in estimating 3D L5/S1 moments and GRFs during symmetric, asymmetric and fast trunk bending, performed by nine male participants. Using an ambulatory IMC system (Xsens/MVN), L5/S1 moments were estimated based on the upper-body segment kinematics using a top-down inverse dynamics analysis, and GRFs were estimated based on full-body segment accelerations. As a reference, a laboratory measurement system was utilized: GRFs were measured with Kistler force plates (FPs), and L5/S1 moments were calculated using a bottom-up inverse dynamics model based on FP data and lower-body kinematics measured with an optical motion capture system (OMC). Correspondence between the OMC+FP and IMC systems was quantified by calculating root-mean-square errors (RMSerrors) of moment/force time series and the interclass correlation (ICC) of the absolute peak moments/forces. Averaged over subjects, L5/S1 moment RMSerrors remained below 10Nm (about 5% of the peak extension moment) and 3D GRF RMSerrors remained below 20N (about 2% of the peak vertical force). ICCs were high for the peak L5/S1 extension moment (0.971) and vertical GRF (0.998). Due to lower amplitudes, smaller ICCs were found for the peak asymmetric L5/S1 moments (0.690-0.781) and horizontal GRFs (0.559-0.948). In conclusion, close correspondence was found between the ambulatory IMC-based and laboratory-based estimates of back load. PMID:26795123
Directory of Open Access Journals (Sweden)
Kupavtsev Vladimir Vladimirovich
2014-02-01
Full Text Available The method of two-sided evaluations is extended to the problems of stability of an elastic non-uniformly compressed rod, the variation formulations of which may be presented in terms of internal bending moments with uniform integral conditions. The problems are considered, in which one rod end is fixed and the other rod end is either restraint or pivoted, or embedded into a support which may be shifted in a transversal direction.For the substantiation of the lower evaluations determination, a sequence of functionals is constructed, the minimum values of which are the lower evaluations for the minimum critical value of the loading parameter of the rod, and the calculation process is reduced to the determination of the maximum eigenvalues of modular matrices. The matrix elements are expressed in terms of integrals of basic functions depending on the type of fixation of the rod ends. The basic functions, with the accuracy up to a linear polynomial, are the same as the bending moments arising with the bifurcation of the equilibrium of a rod with a constant cross-section compressed by longitudinal forces at the rod ends. The calculation of the upper evaluation is reduced to the determination of the maximum eigenvalue of the matrix, which almost coincides with one of the elements of the modular matrices. It is noted that the obtained upper bound evaluation is not worse thanthe evaluation obtained by the Ritz method with the use of the same basic functions.
DEFF Research Database (Denmark)
Jensen, Jørgen Juncher; Mansour, A. E.
2003-01-01
rate. These loads can be due to bow flare slamming, bottom slamming or green water loads as they all can be characterised by a short duration relative to the wave cycle. The magnitude of the bow flare slamming loads is estimated using accurate results from wedge-shaped sections, Zhao and Faltinsen...... (1993) and for green water loads the results from Buchner (1995) and Wang et al .(1998) are applied. The phase lag relative to the wave-induced peak and the decay rate are derived mainly from published experimental results, Sikora, (1998). The results are given in closed-form expressions and the......ABSTRACT: The effect of impulsive loads like slamming and green water on deck on the wave-induced bending mo-ment is estimated by a semi-analytical approach. The impulse loads leading to transient vibrations are described in terms of magnitude, phase lag relative to the wave-induced peak and decay...
Directory of Open Access Journals (Sweden)
Akshay P. Gholkar
2014-07-01
Full Text Available This paper presents the flexural behaviour of basalt fiber reinforced polymer (BFRP strengthened reinforced concrete (RC beams. For flexural strengthening of reinforced concrete beams, total twenty-two beams were cast and tested over an effective span of 900 mm up to failure of the beam under two-point loading. The beams were designed as under-reinforced beams. The beams were bonded with BFRP sheets in single layer and double layers in the bending moment region at the bottom face of the beam. Out of the twenty-two beams two beams were control beams and remaining beams were strengthened after being damaged for various degrees of damage (0 %, 70 %, 80 %, 90% and 100 %. The experimental results show that the beams strengthened show high load carrying capacity.
Indian Academy of Sciences (India)
GOKHAN T TAYYAR
2016-04-01
The reliability and limits of solutions for static structural analysis depend on the accuracy of the curvature and deflection calculations. Even if the material model is close to the actual material behavior, physically unrealistic deflections or divergence problems are unavoidable in the analysis if an appropriate fundamental kinematic theory is not chosen. Moreover, accurate deflection calculation plays an important role in ultimate strength analysis where in-plane stresses are considered. Therefore, a more powerful method is neededto achieve reliable deflection calculation and modeling. For this purpose, a new advanced step was developed by coupling the elasto-plastic material behavior with precise general planar kinematic analysis. The deflection is generated precisely without making geometric assumptions or using differential equations of the deflection curve. An analytical finite strain solution was derived for an elasto-plastic prismatic/non-prismatic rectangular cross-sectioned beam under a uniform moment distribution. A comparison of the analytical results with thosefrom the Abaqus FEM software package reveals a coherent correlation.
Energy Technology Data Exchange (ETDEWEB)
Ng, Jonathan [Center for Heliophysics, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA; Huang, Yi-Min [Center for Heliophysics, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA; Hakim, Ammar [Center for Heliophysics, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA; Bhattacharjee, A. [Center for Heliophysics, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA; Stanier, Adam [Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA; Daughton, William [Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA; Wang, Liang [Space Science Center and Physics Department, University of New Hampshire, Durham, New Hampshire 03824, USA; Germaschewski, Kai [Space Science Center and Physics Department, University of New Hampshire, Durham, New Hampshire 03824, USA
2015-11-01
As modeling of collisionless magnetic reconnection in most space plasmas with realistic parameters is beyond the capability of today's simulations, due to the separation between global and kinetic length scales, it is important to establish scaling relations in model problems so as to extrapolate to realistic scales. Recently, large scale particle-in-cell simulations of island coalescence have shown that the time averaged reconnection rate decreases with system size, while fluid systems at such large scales in the Hall regime have not been studied. Here, we perform the complementary resistive magnetohydrodynamic (MHD), Hall MHD, and two fluid simulations using a ten-moment model with the same geometry. In contrast to the standard Harris sheet reconnection problem, Hall MHD is insufficient to capture the physics of the reconnection region. Additionally, motivated by the results of a recent set of hybrid simulations which show the importance of ion kinetics in this geometry, we evaluate the efficacy of the ten-moment model in reproducing such results. (C) 2015 AIP Publishing LLC.
Ng, Jonathan; Hakim, Ammar; Bhattacharjee, Amitava; Stanier, Adam; Daughton, William; Wang, Liang; Germaschewski, Kai
2015-01-01
As modeling of collisionless magnetic reconnection in most space plasmas with realistic parameters is beyond the capability of today's simulations, due to the separation between global and kinetic length scales, it is important to establish scaling relations in model problems so as to extrapolate to realistic scales. Recently, large scale particle-in-cell (PIC) simulations of island coalescence have shown that the time averaged reconnection rate decreases with system size, while fluid systems at such large scales in the Hall regime have not been studied. Here we perform the complementary resistive MHD, Hall MHD and two fluid simulations using a ten-moment model with the same geometry. In contrast to the standard Harris sheet reconnection problem, Hall MHD is insufficient to capture the physics of the reconnection region. Additionally, motivated by the results of a recent set of hybrid simulations which show the importance of ion kinetics in this geometry, we evaluate the efficacy of the ten-moment model in re...
International Nuclear Information System (INIS)
As modeling of collisionless magnetic reconnection in most space plasmas with realistic parameters is beyond the capability of today's simulations, due to the separation between global and kinetic length scales, it is important to establish scaling relations in model problems so as to extrapolate to realistic scales. Recently, large scale particle-in-cell simulations of island coalescence have shown that the time averaged reconnection rate decreases with system size, while fluid systems at such large scales in the Hall regime have not been studied. Here, we perform the complementary resistive magnetohydrodynamic (MHD), Hall MHD, and two fluid simulations using a ten-moment model with the same geometry. In contrast to the standard Harris sheet reconnection problem, Hall MHD is insufficient to capture the physics of the reconnection region. Additionally, motivated by the results of a recent set of hybrid simulations which show the importance of ion kinetics in this geometry, we evaluate the efficacy of the ten-moment model in reproducing such results
Energy Technology Data Exchange (ETDEWEB)
Ng, Jonathan; Huang, Yi-Min; Hakim, Ammar; Bhattacharjee, A. [Center for Heliophysics, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States); Stanier, Adam; Daughton, William [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Wang, Liang; Germaschewski, Kai [Space Science Center and Physics Department, University of New Hampshire, Durham, New Hampshire 03824 (United States)
2015-11-15
As modeling of collisionless magnetic reconnection in most space plasmas with realistic parameters is beyond the capability of today's simulations, due to the separation between global and kinetic length scales, it is important to establish scaling relations in model problems so as to extrapolate to realistic scales. Recently, large scale particle-in-cell simulations of island coalescence have shown that the time averaged reconnection rate decreases with system size, while fluid systems at such large scales in the Hall regime have not been studied. Here, we perform the complementary resistive magnetohydrodynamic (MHD), Hall MHD, and two fluid simulations using a ten-moment model with the same geometry. In contrast to the standard Harris sheet reconnection problem, Hall MHD is insufficient to capture the physics of the reconnection region. Additionally, motivated by the results of a recent set of hybrid simulations which show the importance of ion kinetics in this geometry, we evaluate the efficacy of the ten-moment model in reproducing such results.
Institute of Scientific and Technical Information of China (English)
赖伟
2012-01-01
以广东沿海某城市火车站超大面积深厚软土采用桩网复合地基进行软土地基处理工程为例,利用FLAC3D数值分析软件,研究不同桩间距、桩帽宽度对桩身弯矩的影响。研究发现,桩间距的增大会使桩身弯矩增大,桩帽宽度的增大会减小桩身弯矩,但桩间距的变化对桩身弯矩的影响更明显。%Taking the treatment engineering by pile-net extra-large area at the railway station in a coastal city in composite foundation against the deep soft soil in Guangdong as the example, the influence of the pile spacing and the pile cap width on bending moment of the pile body is studied with FLAC3D numerical analysis software. The study findings include that the increment of pile spacing will give rise to the increment of bending moment, while the increment of pile cap width will reduce the moment; however the change of pile spacing affects the moment more significantly.
Held, Christian; Liewald, Mathias; Schleich, Ralf; Sindel, Manfred
2010-06-01
The use of lightweight materials offers substantial strength and weight advantages in car body design. Unfortunately such kinds of sheet material are more susceptible to wrinkling, spring back and fracture during press shop operations. For characterization of capability of sheet material dedicated to deep drawing processes in the automotive industry, mainly Forming Limit Diagrams (FLD) are used. However, new investigations at the Institute for Metal Forming Technology have shown that High Strength Steel Sheet Material and Aluminum Alloys show increased formability in case of bending loads are superposed to stretching loads. Likewise, by superposing shearing on in plane uniaxial or biaxial tension formability changes because of materials crystallographic texture. Such mixed stress and strain conditions including bending and shearing effects can occur in deep-drawing processes of complex car body parts as well as subsequent forming operations like flanging. But changes in formability cannot be described by using the conventional FLC. Hence, for purpose of improvement of failure prediction in numerical simulation codes significant failure criteria for these strain conditions are missing. Considering such aspects in defining suitable failure criteria which is easy to implement into FEA a new semi-empirical model has been developed considering the effect of bending and shearing in sheet metals formability. This failure criterion consists of the combination of the so called cFLC (combined Forming Limit Curve), which considers superposed bending load conditions and the SFLC (Shear Forming Limit Curve), which again includes the effect of shearing on sheet metal's formability.
Institute of Scientific and Technical Information of China (English)
田伟; 干钢
2013-01-01
以大型通用软件ANSYS为平台,研究以轴力为主、同时考虑弯矩作用的梭形格构柱的稳定承载能力.通过对不同高度和长细比的梭形格构柱进行非线性稳定计算和参数分析,提出了梭形格构柱稳定承载力的实用计算方法:以弹性特征值为基础计算梭形格构柱的等效长细比,并利用弯矩系数对等效长细比进行修正,得到修正长细比后即可通过查表的方式得到梭形格构柱稳定承载力.%The stability bearing capacity of shuttle-shaped steel lattice columns subject to combined axial force and bending moment is explored through general software ANSYS.Through nonlinear stability analysis and parameter analysis of shuttleshaped steel lattice columns with various heights and slenderness ratios,a practical calculation method is proposed to calculate stability bearing capacity of shuttle-shaped steel lattice columns with bending moment:equal slenderness ratio based on elastic buckling eigenvalues is present; moment ratio is then proposed to modify slenderness ratio,and the ratio can be used to get the stability bearing capacity of shuttle-shaped steel lattice columns through tables.
Monitoring Composites under Bending Tests with Infrared Thermography
Directory of Open Access Journals (Sweden)
Carosena Meola
2012-01-01
Full Text Available The attention of the present paper is focused on the use of an infrared imaging device to monitor the thermal response of composite materials under cyclic bending. Three types of composites are considered including an epoxy matrix reinforced with either carbon fibres (CFRP or glass fibres (GFRP and a hybrid composite involving glass fibres and aluminium layers (FRML. The specimen surface, under bending, displays temperature variations pursuing the load variations with cooling down under tension and warming up under compression; such temperature variations are in agreement with the bending moment. It has been observed that the amplitude of temperature variations over the specimen surface depends on the material characteristics. In particular, the presence of a defect inside the material affects the temperature distribution with deviation from the usual bending moment trend.
Zhen, Wu; Wanji, Chen
2010-04-01
A C0-type global-local higher order theory including interlaminar stress continuity is proposed for the cross-ply laminated composite and sandwich plates in this paper, which is able to a priori satisfy the continuity conditions of transverse shear stresses at interfaces. Moreover, total number of unknowns involved in the model is independent of number of layers. Compared to other higher-order theories satisfying the continuity conditions of transverse shear stresses at interfaces, merit of the proposed model is that the first derivatives of transverse displacement w have been taken out from the in-plane displacement fields, so that the C0 interpolation functions is only required during its finite element implementation. To verify the present model, a C0 three-node triangular element is used for bending analysis of laminated composite and sandwich plates. It ought to be shown that all variables involved in present model are discretized by only using linear interpolation functions within an element. Numerical results show that the C0 plate element based on the present theory may accurately calculate transverse shear stresses without any postprocessing, and the present results agree well with those obtained from the C1-type higher order theory. Compared with the C1 plate bending element, the present finite element is simple, convenient to use and accurate enough.
Energy Technology Data Exchange (ETDEWEB)
Saori Pastore, S.C. Pieper, Rocco Schiavilla, Robert Wiringa
2013-03-01
Quantum Monte Carlo calculations of electromagnetic moments and transitions are reported for A{<=}9 nuclei. The realistic Argonne v{sub 18} two-nucleon and Illinois-7 three-nucleon potentials are used to generate the nuclear wave functions. Contributions of two-body meson-exchange current (MEC) operators are included for magnetic moments and M1 transitions. The MEC operators have been derived in both a standard nuclear physics approach and a chiral effective field theory formulation with pions and nucleons including up to one-loop corrections. The two-body MEC contributions provide significant corrections and lead to very good agreement with experiment. Their effect is particularly pronounced in the A=9, T=3/2 systems, in which they provide up to ~20% (~40%) of the total predicted value for the {sup 9}Li ({sup 9}C) magnetic moment.
Institute of Scientific and Technical Information of China (English)
赵军涛; 王志刚; 袁浩; 刘修水
2013-01-01
The secondary be nding moment from three-dimension prestressing is firstly proposed to calculate the prestress in the Caohe aqueduct of Middle Route Project of S-N water diversion. The calculation of the secondary bending moment and it’s the impact on the structure of the aqueduct body is discussed with the design examples in the Caohe aqueduct in this paper. The experience summarized in this paper can offer help and reference in calculating three-dimension prestressing in the large aqueduct.%南水北调中线漕河渡槽，首次将三向预应力次生弯矩影响考虑到结构设计当中，本文结合漕河渡槽槽身设计实例，对次生弯矩的计算及影响分析进行了论述，并总结了经验，为大型渡槽多向预应力设计提供了借鉴和参考。
Bending strength analysis of steel-composite submerged floating tunnels
Han, T H; Won, D.; Han, S. H.; Park, W. S.; Yum, K.D.
2013-01-01
A submerged floating tunnel (SFT) must have enough strength to resist to various external loadings such as bending, torsion, tension, and compression. The expected main deformation of SFT is caused by bending moment. And this bending moment makes tensile stress and compression stress on the wall of SFT. Thus, bending moment is a main affecting factor on the safety of SFT. Until now, a reinforced concrete tunnel was suggested for SFT by other researchers. In this study, an internal...
Bending stresses in Facetted Glass Shells
DEFF Research Database (Denmark)
Bagger, Anne; Jönsson, Jeppe; Almegaard, Henrik
structure will locally cause bending moments in the loaded facets. The bending stresses are dependent on the stiffness of the joints. Approximate solutions are developed to estimate the magnitude of the bending stresses. A FE-model of a facetted glass shell structure is used to validate the expressions and...
Large charge moment change lightning on 31 May to 1 June 2013, including the El Reno tornadic storm
Lang, Timothy J.; Cummer, Steven A.; Petersen, Danyal; Flores-Rivera, Lizxandra; Lyons, Walter A.; MacGorman, Donald; Beasley, William
2015-04-01
On 31 May 2013, a line of severe tornadic thunderstorms (the El Reno event) developed during the local afternoon in central Oklahoma, USA. Within range of the Oklahoma Lightning Mapping Array, the evolution of the event can be separated into three distinct periods: an Early period (before 02:00 UTC on 1 June) when the storm consisted of discrete supercells, a Middle period (02:00-05:00 UTC) when the convection began merging into a linear feature and stratiform precipitation developed, and a Late period (after 05:00 UTC) featuring a mature mesoscale convective system (MCS). Each of these periods demonstrated distinct patterns in the large (>100 C km) charge moment change (CMC) lightning that was produced. During the Early period, large-CMC positive cloud-to-ground (+CG) lightning was produced in the convective cores of supercells. These flashes were small in area (typically 500 km2, >300 C km) in the developing stratiform, similar to typical sprite-parent lightning in MCSs. During the Late period, convective large CMC +CGs ceased and instead large-CMC negative CGs were produced in and near the MCS convection. These flashes neutralized charge both in convection as well as in adjacent stratiform and anvil precipitation. The results suggest that the CMC metric has potential applications for studying tropospheric weather.
International Nuclear Information System (INIS)
The comparison of limit load based on small displacement limit analysis and collapse load based on large displacement analysis for shape-imperfect pipe bends, under combined in-plane closing bending and an internal pressure, were carried out using finite element method. The limit and collapse moments were obtained from moment–rotation curves drawn for each model. Twice-elastic-slope method was used to obtain collapse load. The effect of thinning on limit and collapse moments are minimal and hence thinning need not be considered for the analysis of pipe bends. The influence of ovality on both limit and collapse loads for most of the cases considered are significant. Comparison of effect of ovality on limit and collapse loads reveals that the determination of collapse load is preferable when ovality is included in the analysis of pipe bend. A closed-form solution is presented to include ovality in the determination of the collapse load of pipe bends. Highlights: ► Comparison of limit and collapse loads for shape-imperfect pipe bends is performed. ► Shape imperfections considered are ovality and thinning. ► Finite element limit analyses use small and large geometry change effects. ► Twice-elastic-slope method was used to obtain plastic loads. ► Determination of collapse load is preferable when ovality is included in the analysis.
Williams, Kate
2012-01-01
The informatics moment is the moment when a person seeks help in using some digital technology that is new to him or her. This article examines the informatics moment in people's everyday lives as they sought help at a branch public library. Four types of literacy were involved: basic literacy (reading and writing), computer literacy (use of a…
Institute of Scientific and Technical Information of China (English)
祝效华; 董亮亮; 童华; 高原; 庞然
2013-01-01
套管下入水平井弯曲段时,套管螺纹是否已发生屈服对于随后的钻进和油气井生产有至关重要的影响,而目前国内外对于井眼曲率(弯矩)对套管螺纹连接强度和密封性能影响的研究极少.笔者基于虚功原理、接触非线性理论及von Mises屈服准则,建立了API短圆套管螺纹连接的三维计算模型,研究了拉弯复合载荷下连接螺纹的应力分布规律,指出井眼曲率(弯矩)对套管的连接强度和密封性能影响极大,并通过大量计算绘制了给定井眼曲率时的最大许用套管悬重图,综合考虑连接强度和密封能力推荐了API短圆套管螺纹标准所列锥度、螺距、螺纹长度、牙高参数系列中的最优值.%While casing goes down into the curved section of a horizontal well, whether casing threads have been yielded has a great influence on following drilling and oil-gas production. However, there have been very few researches on mechanical behaviors of casing threads while casing goes down through the curved portion of a horizontal well, such as connection strength and sealing ability of the casing. Based on the principle of virtual work, nonlinear contact theory and von Mises yield criterion, we established a 3-D calculation model for the API short-round casing thread connection, examined the stress distribution of short-round casing threads under combined load of stretching and bending moment, and figured out that hole curvature (bending moment) would significantly influence the connection strength and sealing ability of casing. In addition, a maximum allowance hanging load for various given hole curvature was worked out through a large number of calculations. Based on synthetic considerations of thread connection performance and sealing ability,we recommended the optimized parameters of the API short-round casing thread criteria, including thread taper, thread pitch, thread length and thread ridge thickness. This research has an
Bending stresses in Facetted Glass Shells
DEFF Research Database (Denmark)
Bagger, Anne; Jönsson, Jeppe; Almegaard, Henrik
A shell structure of glass combines a highly effective structural principle with a material of optimal permeability to light. A facetted shell structure has a piecewise plane geometry, and together the facets form an approximation to a curved surface. A distributed load on a plane-based facetted...... structure will locally cause bending moments in the loaded facets. The bending stresses are dependent on the stiffness of the joints. Approximate solutions are developed to estimate the magnitude of the bending stresses. A FE-model of a facetted glass shell structure is used to validate the expressions and...
Behavior of concrete filled FRP tubes under fully reversed cyclic bending
International Nuclear Information System (INIS)
Concrete filled Fiber Reinforced Polymer (FRP) tubes (CFFT) are currently being used as piles in corrosive marine applications and as columns in bridge piers, and could be used in overhead sign structures. CFFTs provide a non-corrosive alternative to conventional materials. Studies conducted on CFFTs in the past decade have been mostly focused on the short-term monotonic behavior of this system in bending and under axial loads, with hardly any information available on their fatigue behavior. In this paper the details of a research program that was conducted to address this issue and its results are presented. The program included the testing of two full-scale specimens under reversed cyclic bending. The program also included the testing of several coupons, cut from the tubes in tension-tension fatigue. The full scale tests showed that CFFTs seem to have a relatively short fatigue life under bending moments of 40% and higher of their ultimate static bending moment capacities and that strains and deflections tend to increase gradually during cyclic bending indicating a stiffness degradation behavior. The coupon test showed that rapid stiffness degradation occurs initially then reduces due to the cracking of matrix in the hoop layers and that a fatigue life of millions of cycles could be reached for stresses less than 30% of the ultimate tensile stress. (author)
Energy Technology Data Exchange (ETDEWEB)
Michael Ramsey-Musolf; Wick Haxton; Ching-Pang Liu
2002-03-29
Nuclear anapole moments are parity-odd, time-reversal-even E1 moments of the electromagnetic current operator. Although the existence of this moment was recognized theoretically soon after the discovery of parity nonconservation (PNC), its experimental isolation was achieved only recently, when a new level of precision was reached in a measurement of the hyperfine dependence of atomic PNC in 133Cs. An important anapole moment bound in 205Tl also exists. In this paper, we present the details of the first calculation of these anapole moments in the framework commonly used in other studies of hadronic PNC, a meson exchange potential that includes long-range pion exchange and enough degrees of freedom to describe the five independent S-P amplitudes induced by short-range interactions. The resulting contributions of pi-, rho-, and omega-exchange to the single-nucleon anapole moment, to parity admixtures in the nuclear ground state, and to PNC exchange currents are evaluated, using configuration-mixed shell-model wave functions. The experimental anapole moment constraints on the PNC meson-nucleon coupling constants are derived and compared with those from other tests of the hadronic weak interaction. While the bounds obtained from the anapole moment results are consistent with the broad ''reasonable ranges'' defined by theory, they are not in good agreement with the constraints from the other experiments. We explore possible explanations for the discrepancy and comment on the potential importance of new experiments.
Damage Analysis of Rectangular Section Composite Beam under Pure Bending
Liu, Yiping; Xiao, Fan; Liu, Zejia; Tang, Liqun; Fang, Daining
2013-02-01
Laminated composite beams are commonly used in engineering applications involving macro to nano structures. Based on the assumption that plain sections remain plain after deformation, this paper analyzes stress distributions in cross-ply laminated composite beams with rectangular cross-sections, and formulates the basic damage equations through Kachanov's damage definition and Janson's failure criterion. The location of the neutral axis and the ultimate bending moment are obtained for pure bending cases. The effect of the elastic modulus of the two layers on the damage evolution is analyzed; a reasonable damage composite beam model is proposed to predict the ultimate bending moment.
Experimental verification of a weak zone model for timber in bending
DEFF Research Database (Denmark)
Källsner, B.; Ditlevsen, Ove Dalager; Salmela, K.
1997-01-01
In order to verify a stochastic model for the variation of bending strength within and between structural timber members, tests with long members subjected to constant bending moment have been performed. The span with constant moment contained between five and nine weak zones, i.e. zones with a...
DEFF Research Database (Denmark)
Swann, Andrew Francis; Madsen, Thomas Bruun
2012-01-01
We introduce a notion of moment map adapted to actions of Lie groups that preserve a closed three-form. We show existence of our multi-moment maps in many circumstances, including mild topological assumptions on the underlying manifold. Such maps are also shown to exist for all groups whose second...... and third Lie algebra Betti numbers are zero. We show that these form a special class of solvable Lie groups and provide a structural characterisation. We provide many examples of multi-moment maps for different geometries and use them to describe manifolds with holonomy contained in G(2) preserved by...
Energy Technology Data Exchange (ETDEWEB)
Courant, E.D. [Brookhaven National Lab., Upton, NY (United States); Garren, A.
1985-10-01
The phase shifting trombones considered up to now for SSC application consisted of sets of evenly spaced quadrupoles separated by drift spaces. One such trombone was placed between a dispersion suppressor and a crossing insertion, so that the trombone had zero dispersion. With such trombones, it is possible to change {beta}{sup *} at constant tune, or to change the tunes by several units without altering the cell phase advances in the arcs. An objection to the above type of phase trombone is that it adds to the circumference, since no bending is included. This objection may or may not be valid depending on the potential usefulness of the drift spaces in them. In this note the authors show an alternative trombone design in which dipoles are included between the quadrupoles as in the normal arc cells. Since these trombones have dispersion, they are placed at the ends of the arcs, to be followed in turn by the dispersion suppressors and crossing insertions.
Semiconductor laser beam bending
YILDIRIM, REMZİ; ÇELEBİ, FATİH VEHBİ
2015-01-01
This study is about a single-component cylindrical structured lens with a gradient curve that was used for bending laser beams. It operates under atmospheric conditions and bends the laser beam independently of temperature, pressure, polarity, polarization, magnetic field, electric field, radioactivity, and gravity. A single-piece cylindrical lens that can bend laser beams was developed. Lenses are made of transparent, tinted, or colored glass and are used to undermine or absorb the energy of...
A derivation of the generalized model of strains during bending of metal tubes at bending machines
Directory of Open Access Journals (Sweden)
Śloderbach Z.
2014-02-01
Full Text Available According to the postulate concerning a local change of the “actual active radius” with a bending angle in the bend zone, a generalized model of strain during metal tube bending was derived. The tubes should be subjected to bending at tube bending machines by the method of wrapping at the rotating template and with the use of a lubricated steel mandrel. The model is represented by three components of strain in the analytic form, including displacement of the neutral axis. Generalization of the model during bending metal tubes at the tube bending machines as compared with the existing papers (Śloderbach, 1999; Śloderbach and Rechul, 2000 consists in including the neutral axis displacement and possibility of determination of strains at each point along the thickness of the wall of the bent tube in the bending and bend zone. The derived scheme of strain satisfies initial and boundary kinematic conditions of the bending process, conditions of continuity and inseparability of strains. The obtained analytic expressions can be classified as acceptable from the kinematic point of view
International Nuclear Information System (INIS)
The mechanical behavior of a silicon crystal under bending is investigated. For a crystal of length 30 mm and thickness 3 mm, to achieve the specified bend angle of 0.64 mrad, the appropriate angle of the aluminum punches is 0.96 mrad
Forming characteristics of thin-walled tube bending process with small bending radius
Institute of Scientific and Technical Information of China (English)
LI Heng; YANG He; ZHAN Mei; GU Rui-Jie
2006-01-01
Currently requirements of thin-walled tube with small bending radius cause the defects such as wrinkling,overthinning and cross-section distortion more prone to occur in bending process. Based on the analysis of the forming characteristics by analytical and experimental methods,a complete 3D elastic-plastic FEM model of the process was developed using ABAQUS/Explicit code,including bending process,balls retracting and unloading process,and thus the plastic deformation characteristics with small bending radius were investigated. The main results show that: 1) The utmost deformation feature of the NC bending process is its continuous progressive deformation. 2) The occurring conditions of the defects such as wrinkling and tension instability in the process are obtained. The wrinkling is traditional on the double compressive stresses state and the tension instability is on the double tension stresses state. 3) The enhanced non-uniform deformation in thin-walled tube with small bending radius is demonstrated by comparing the stress/ strains distributions under the 1.5D and 1D bending conditions. 4) For 1D small bending process,a new method-"stepped mandrel retraction" is proposed to improve the bending quality in experiment according to the FE simulation. The simulation results are verified by experiment.
Oceanic Plate Bending Along the Manila Trench
Zhang, F.; Lin, J.; Zhan, W.
2014-12-01
We quantify along-trench variations in plate flexural bending along the Manila trench in the South China Sea. A 3-D interpreted flexural deformation surface of the subducting South China Sea Plate was obtained by removing from the observed bathymetry the effects of sediment loading, isostatically-compensated topography based on gravity modeling, age-related lithospheric thermal subsidence, and residual short-wavelength features. We analyzed flexural bending of 21 across-trench profile sections along the Manila trench and then calculated five best-fitting tectonic and plate parameters that control the flexural bending for each of the across-trench profile sections. Results of analysis revealed significant along-trench variations: The trench relief of the Manila trench varies from 0.8 to 2.2 km, trench-axis vertical loading (-V0) from -0.4x1012 to 1.21x1012 N/m, and axial bending moment (-M0) from 0.005x1017 to 0.6x1017 N. The effective elastic plate thickness seaward of the Manila outer-rise region (TeM) ranges from 30 to 40 km, while that trench-ward of the outer-rise (Tem) ranges from 11 to 30 km. This corresponds to a reduction in Te of 26-63% for the Manila trench. The transition from TeM to Tem occurs at a breaking distance of 50-120 km from the Manila trench axis. The axial vertical loading, bending moment, and the effective elastic thickness of the Manila trench are much smaller than the Mariana trench (Zhang et al., 2014). The contrast in the flexural bending between the Mariana and Manila trenches might be related to the difference in the ages of the subducting plates and other tectonic variables. Zhang, F., Lin, J., Zhan, W., 2014. Variations in oceanic plate bending along the Mariana trench, Earth Planet. Sci. Lett. 401, 206-214. doi: 10.1016/j.epsl.2014.05.032
Dispersion suppressors with bending
Energy Technology Data Exchange (ETDEWEB)
Garren, A.
1985-10-01
Dispersion suppressors of two main types are usually used. In one the cell quadrupole focussing structure is the same as in normal cells but some of the dipoles are replaced by drifts. In the other, the quadrupole strengths and/or spacings are different from those of the normal cells, but the bending is about the same as it is in the cells. In SSC designs to date, dispersion suppressors of the former type have been used, consisting of two cells with bending equivalent to one. In this note a suppressor design with normal bending and altered focussing is presented. The advantage of this scheme is that circumference is reduced. The disadvantages are that additional special quadrupoles must be provided (however, they need not be adjustable), and the maximum beta values within them are about 30% higher than the cell maxima.
Standard test methods for bend testing of material for ductility
American Society for Testing and Materials. Philadelphia
2009-01-01
1.1 These test methods cover bend testing for ductility of materials. Included in the procedures are four conditions of constraint on the bent portion of the specimen; a guided-bend test using a mandrel or plunger of defined dimensions to force the mid-length of the specimen between two supports separated by a defined space; a semi-guided bend test in which the specimen is bent, while in contact with a mandrel, through a specified angle or to a specified inside radius (r) of curvature, measured while under the bending force; a free-bend test in which the ends of the specimen are brought toward each other, but in which no transverse force is applied to the bend itself and there is no contact of the concave inside surface of the bend with other material; a bend and flatten test, in which a transverse force is applied to the bend such that the legs make contact with each other over the length of the specimen. 1.2 After bending, the convex surface of the bend is examined for evidence of a crack or surface irregu...
Bending response of single layer MoS2
Xiong, Si; Cao, Guoxin
2016-03-01
Using molecular mechanics (or dynamics) simulations, three different approaches, including the targeted molecular mechanics, four-point bending and nanotube methods, are employed to investigate the bending response of single layer MoS2 (SLMoS2), among which four-point bending is the most accurate approach to determine the bending stiffness according to the continuum theory. It is found that when the bending curvature radius is large enough (e.g. >4 nm), three approaches will give the same bending stiffness of SLMoS2 and the bending behavior is isotropic for SLMoS2, whereas the nanotube method with small tubes (e.g. theory, the revised Stillinger-Weber (SW) and reactive empirical bond-order (REBO) potentials can give the reasonable bending stiffness of SLMoS2 (8.7-13.4 eV) as well as the effective deformed conformation. In addition, since the Mo-S bond deformation of SLMoS2 under bending is similar to that under in-plane tension/compression, the continuum bending theory can quite accurately predict the bending stiffness of SLMoS2 if a reasonable thickness of SLMoS2 is given. For SLMoS2, the reasonable thickness should be larger than the distance between its two S atomic planes and lower than the distance between two Mo atomic planes of bulk MoS2 crystal, e.g. 0.375-0.445 nm.
Bending and stretching of plates
Mansfield, E H; Hemp, W S
2014-01-01
The Bending and Stretching of Plates deals with elastic plate theory, particularly on small- and large-deflexion theory. Small-deflexion theory concerns derivation of basic equations, rectangular plates, plates of various shapes, plates whose boundaries are amenable to conformal transformation, plates with variable rigidity, and approximate methods. Large-deflexion theory includes general equations and some exact solutions, approximate methods in large-deflexion theory, asymptotic large-deflexion theories for very thin plates. Asymptotic theories covers membrane theory, tension field theory, a
International Nuclear Information System (INIS)
Impulse approximation and pion-exchange current contributions to the trinucleon magnetic moments are calculated using wave functions generated by solving the configuration-space Faddeev equations for a variety of nucleon-nucleon force models. Careful attention is paid to the origin of important exchange current contributions. Numerical results are compared with previously published calculations and with the experimental data. An attempt is made to isolate and understand sources of discrepancy between our results and those previously published. Calculations which include both impulse and pion-exchange current contributions are in fairly good agreement with experiment, whereas calculations which include only the impulse approximation term are not
1980-01-01
The very particular lattice of the AA required 2 types of dipole (bending magnets; BLG, long and narrow; BST, short and wide). The BLG had a steel length of 4.70 m, a good field width of 0.24 m, and a weight of about 70 t. Jean-Claude Brunet inspects the lower half of a BLG. For the BST magnets see 7811105 and 8006036.
Moment-to-Moment Emotions during Reading
Graesser, Arthur C.; D'Mello, Sidney
2012-01-01
Moment-to-moment emotions are affective states that dynamically change during reading and potentially influence comprehension. Researchers have recently identified these emotions and the emotion trajectories in reading, tutoring, and problem solving. The primary learning-centered emotions are boredom, frustration, confusion, flow (engagement),…
The effect of cracks on the limit load of pipe bends under in-plane bending
International Nuclear Information System (INIS)
The limit analysis of the in-plane bending of curved tubes had received attention previously, but the effect of defects in the tube has not been considered. A lower bound has been established which, with no defects present, is in agreement with previous theoretical work. The method of linear programming allows cracks to be introduced into analysis, and results have been obtained for various geometries of defect. The results show that the presence of cracks in the pipe bend can have a marked effect on the theoretical limit load: a part-through crack penetrating only half the wall thickness will reduce the limit moment by up to 10%. The worst possible case of a through-crack may reduce the limit load by 60%. (author)
Axisymmetrical bending of circular plates with eccentric stiffeners
International Nuclear Information System (INIS)
Small deflection bending theory of stiffened circular plates with uniformly spaced radial and circunferential ribs is presented. Equilibrium differential equations for the axisymmetric case, in terms of the displacements u and w of the middle surface of the plate are derived, and their general solutions are found. Closed form solutions for the circular plate with uniformly distributed bending moments along its edge are given for the special case in which geometrical and elastic properties of the ribs are constant and equal along both radial and circunferential directions. (Author)
Sorting of bed load sediment by flow in meander bends.
Parker, G.; Andrews, E.D.
1985-01-01
Equilibrium sorting of coarse mobile bed load sediment in meander bends is considered. A theory of two-dimensional bed load transport of graded material, including the effects of gravity on lateral slopes and secondary currents, is developed. This theory is coupled with a simple tratement of flow in bends, an analytically determined bend shape, and the condition of continuity of each grain size range in transport to describe sorting. The theory indicates that the locus of coarse sediment shifts from the inside bank to the outside bank near the bend apex, as is observed.-Authors
Haxton, W.C.; Liu, C. P.; Ramsey-Musolf, M. J.
2001-01-01
Nuclear anapole moments are parity-odd, time-reversal-even E1 moments of the electromagnetic current operator. Although the existence of this moment was recognized theoretically soon after the discovery of parity nonconservation (PNC), its experimental isolation was achieved only recently, when a new level of precision was reached in a measurement of the hyperfine dependence of atomic PNC in 133Cs. An important anapole moment bound in 205Tl also exists. In this paper, we present the details o...
Directory of Open Access Journals (Sweden)
Sergio Baragetti
2016-01-01
Full Text Available Hydraulic actuators are commonly adopted in machines and structures to provide translating forces with significant magnitudes. Although their application dates back to the industrial revolution, their bending behavior under compression is typically addressed by simple Euler’s instability analysis on the rod, neglecting effects such as the cylinder inertia and stiffness, the presence of contact elements in the cylinder-rod junction and on the piston, geometrical misalignments and imperfections, and friction moments at the support. Such simplifications lead to unjustified reduced critical load calculations on the component. In the present paper, a complete mathematical formulation, which accounts for such effects, is presented and validated against experimental data. A numerical sensitivity analysis is conducted, to assess the contributions of initial rectilinear imperfections, wear rings stiffness and dimension, and supports friction on the actuator’s limit buckling load and bending behavior under compression. Results are presented, including the effect of the cited parameters on the buckling load, providing a reliable tool for the mechanical designer. In particular, an optimum position for the wear ring distance is found. Moreover, increased wear ring stiffness and reduced imperfections increase the buckling load and reduce the bending stresses before the critical load.
Solvents level dipole moments.
Liang, Wenkel; Li, Xiaosong; Dalton, Larry R; Robinson, Bruce H; Eichinger, Bruce E
2011-11-01
The dipole moments of highly polar molecules measured in solution are usually smaller than the molecular dipole moments that are calculated with reaction field methods, whereas vacuum values are routinely calculated in good agreement with available vapor phase data. Whether from Onsager's theory (or variations thereof) or from quantum mechanical methods, the calculated molecular dipoles in solution are found to be larger than those measured. The reason, of course, is that experiments measure the net dipole moment of solute together with the polarized (perturbed) solvent "cloud" surrounding it. Here we show that the reaction field charges that are generated in the quantum mechanical self-consistent reaction field (SCRF) method give a good estimate of the net dipole moment of the solute molecule together with the moment arising from the reaction field charges. This net dipole is a better description of experimental data than the vacuum dipole moment and certainly better than the bare dipole moment of the polarized solute molecule. PMID:21923185
Wide range pure bending strains of Nb3Sn wires
International Nuclear Information System (INIS)
Pure bending behavior of Nb3Sn wire over a wide range of bending has been characterized. A previously developed test device designed to apply variable bending strains to Nb3Sn strands using a beam style sample holder was used. Based on finite element and experimental investigations, two sample holder beams were developed to cover pure bending strains up to 1.25% for ITER-type Nb3Sn wires. These newly designed beams were optimized to apply consistent and uniform pure bending strains to Nb3Sn strands over the entire bending range. Their performance was evaluated by testing two ITER-type Nb3Sn wires including one internal tin and one bronze route. The internal tin strands experienced around 55% critical current degradation at 1.25% bending strain while the critical current of the bronze route strands were only reduced by 40%. Upon removal of the bending load, the internal tin wires experienced significant permanent degradation whereas the bronze route wires were completely reversible. These critical current results were evaluated and explained using an existing integrated model accounting for neutral axis shift, current transfer length, filament breakage and uniaxial strain release under pure bending loads. (paper)
Thiria, Benjamin
2010-01-01
Wing flexibility governs the flying performance of flapping wing flyers. Here we use a self-propelled flapping-wing model mounted on a "merry-go-round" to investigate the effect of wing compliance on the propulsive efficiency of the system. Our measurements show that the elastic nature of the wings can lead not only to a substantial reduction of the consumed power, but also to an increment of the propulsive force. A scaling analysis using a flexible plate model for the wings points out that, for flapping flyers in air, the time-dependent shape of the elastic bending wing is governed by the wing inertia. Based on this prediction, we define the ratio of the inertial forces deforming the wing to the elastic restoring force that limits the deformation as the 'elasto-inertial number'. Our measurements with the self-propelled model confirm that it is the appropriate structural parameter to describe flapping flyers with flexible-wings.
BENDING-SHEAR INTERACTION OF LONGITUDINALLY STIFFENED GIRDERS
Beg, Darko; Sinur, Franc
2011-01-01
To understand behaviour of longitudinally stiffened plated girders subjected to high bending moments and shear forces, four tests on large scale test specimens were performed. The results of these tests were used to verify the numerical model, which was employed for further parametric studies. With a verified simplified numerical model a parametric nonlinear analysis was systematically carried out to determine the resistance of longitudinally stiffened plated girders. Based on 630 numerical s...
Kinematic Moment of Inertia of e-e Rare Earths Nuclei
Kelabi, Mohamed E.
2013-01-01
The kinematic moment of inertia of the rare earth even-even nuclei was calculated using three parametric energy based expression. The plot of kinematic moment of inertia versus nuclear spin shows a better sensitivity to back bending than energy plot.
West, Adam
2016-01-01
From the famous experiments of Stern and Gerlach to the present, measurements of magnetic dipole moments, and searches for electric dipole moments of ``elementary'' particles have played a major role in our understanding of sub-atomic physics. In this talk I discuss the progress on measurements and theory of the magnetic dipole moments of the electron and muon. I also discuss a new proposal to search for a permanent electric dipole moment (EDM) of the muon and put it into the more general con...
Characterizing flow fluctuations with moments
Bhalerao, Rajeev S; Pal, Subrata
2015-01-01
We present a complete set of multiparticle correlation observables for ultrarelativistic heavy-ion collisions. These include moments of the distribution of the anisotropic flow in a single harmonic, and also mixed moments, which contain the information on correlations between event planes of different harmonics. We explain how all these moments can be measured using just two symmetric subevents separated by a rapidity gap. This presents a multi-pronged probe of the physics of flow fluctuations. For instance, it allows to test the hypothesis that event-plane correlations are generated by non-linear hydrodynamic response. We illustrate the method with simulations of events in A MultiPhase Transport (AMPT) model.
Characterizing flow fluctuations with moments
International Nuclear Information System (INIS)
We present a complete set of multiparticle correlation observables for ultrarelativistic heavy-ion collisions. These include moments of the distribution of the anisotropic flow in a single harmonic and also mixed moments, which contain the information on correlations between event planes of different harmonics. We explain how all these moments can be measured using just two symmetric subevents separated by a rapidity gap. This presents a multi-pronged probe of the physics of flow fluctuations. For instance, it allows to test the hypothesis that event-plane correlations are generated by non-linear hydrodynamic response. We illustrate the method with simulations of events in A MultiPhase Transport (AMPT) model
Moment graphs and representations
DEFF Research Database (Denmark)
Jantzen, Jens Carsten
2012-01-01
Moment graphs and sheaves on moment graphs are basically combinatorial objects that have be used to describe equivariant intersectiion cohomology. In these lectures we are going to show that they can be used to provide a direct link from this cohomology to the representation theory of simple Lie...
Zichittella, Jack
1998-01-01
Discusses Henri Cartier-Bresson's notion of the "aesthetic of the decisive moment" and its role in photographic composition. Argues that recording spontaneous moments from real life can produce significant and complex photographs. Suggests that instilling this technique in photography students frees them to experiment without fear of failure. (DSK)
Valentine, Christine
2007-01-01
The "moment of death," once a dominant concept in preparing for a "good death", has been eclipsed by a focus on the wider concept of the "dying trajectory". However, findings from interviews with 25 bereaved individuals suggest that dying loved ones' final moments may still be experienced as highly significant in their own right. In some accounts the dying individual's final moments did not feature or made little impression, either because the survivor was not present, or there was no obviously definable moment, or because other, usually medical factors, such as whether to resuscitate the person, took precedence. However, in six cases such moments were constructed as profound, special, and memorable occasions. These constructions are explored in relation to achieving a good death, the dying trajectory as a whole, and making sense of the bereavement experience. Their implications for sociological theories of identity and embodiment are also considered. PMID:18214069
Closed forms and multi-moment maps
DEFF Research Database (Denmark)
Madsen, Thomas Bruun; Swann, Andrew Francis
2013-01-01
We extend the notion of multi-moment map to geometries defined by closed forms of arbitrary degree. We give fundamental existence and uniqueness results and discuss a number of essential examples, including geometries related to special holonomy. For forms of degree four, multi-moment maps are...
Closed forms and multi-moment maps
DEFF Research Database (Denmark)
Madsen, Thomas Bruun; Swann, Andrew Francis
We extend the notion of multi-moment map to geometries defined by closed forms of arbitrary degree. We give fundamental existence and uniqueness results and discuss a number of essential examples, including geometries related to special holonomy. For forms of degree four, multi-moment maps are...
Buoyancy, bending, and seismic visibility in deep slab stagnation
Bina, Craig R.; Kawakatsu, Hitoshi; Suetsugu, D.; Bina, C.; Inoue, T.; Wiens, D.; Jellinek, M.
2010-11-01
The petrological consequences of deep subhorizontal deflection ("stagnation") of subducting slabs should affect both apparent seismic velocity structures and slab morphology. We construct kinematic thermal models of stagnant slabs and perform thermodynamic modeling of the consequent perturbation of high-pressure phase transitions in mantle minerals, focusing upon Japan as our study area. We calculate associated thermo-petrological buoyancy forces and bending moments which (along with other factors such as viscosity variations and rollback dynamics) may contribute to slab deformation. We consider effects of variations in depth of stagnation, post-stagnation dip angle, phase transition sharpness, transition triplication due to multiple intersection of geotherms with phase boundaries, and potential persistence of metastable phases due to kinetic hindrance. We also estimate seismic velocity anomalies, as might be imaged by seismic tomography, and corresponding seismic velocity gradients, as might be imaged by receiver-function analysis. We find that buoyant bending moment gradients of petrological origin at the base of the transition zone may contribute to slab stagnation. Such buoyancy forces vary with the depth at which stagnation occurs, so that slabs may seek an equilibrium slab stagnation depth. Metastable phase bending moment gradients further enhance slab stagnation, but they thermally decay after ∱/4600•700 km of horizontal travel, potentially allowing stagnant slabs to descend into the lower mantle. Stagnant slabs superimpose zones of negative velocity gradient onto a depressed 660-km seismic discontinuity, affecting the seismological visibility of such features. Seismologically resolvable details should depend upon both stagnation depth and the nature of the imaging technique (travel-time tomography vs. boundary-interaction phases). While seismic tomography appears to yield images of stagnant slabs, discontinuity topography beneath Japan resolved by
1984 Deer Harvest Summary for Holla Bend National Wildlife Refuge
US Fish and Wildlife Service, Department of the Interior — This memo summarizes the 1984 deer harvest for Holla Bend National Wildlife Refuge. Tables summarize numerical findings, including bucks, does, and points.
Updating neutrino magnetic moment constraints
Directory of Open Access Journals (Sweden)
B.C. Cañas
2016-02-01
Full Text Available In this paper we provide an updated analysis of the neutrino magnetic moments (NMMs, discussing both the constraints on the magnitudes of the three transition moments Λi and the role of the CP violating phases present both in the mixing matrix and in the NMM matrix. The scattering of solar neutrinos off electrons in Borexino provides the most stringent restrictions, due to its robust statistics and the low energies observed, below 1 MeV. Our new limit on the effective neutrino magnetic moment which follows from the most recent Borexino data is 3.1×10−11μB at 90% C.L. This corresponds to the individual transition magnetic moment constraints: |Λ1|≤5.6×10−11μB, |Λ2|≤4.0×10−11μB, and |Λ3|≤3.1×10−11μB (90% C.L., irrespective of any complex phase. Indeed, the incoherent admixture of neutrino mass eigenstates present in the solar flux makes Borexino insensitive to the Majorana phases present in the NMM matrix. For this reason we also provide a global analysis including the case of reactor and accelerator neutrino sources, presenting the resulting constraints for different values of the relevant CP phases. Improved reactor and accelerator neutrino experiments will be needed in order to underpin the full profile of the neutrino electromagnetic properties.
Bends in nanotubes allow electric spin control and coupling
DEFF Research Database (Denmark)
Flensberg, Karsten; Marcus, Charles Masamed
2010-01-01
fields. Device geometries that allow general rotation of single spins are presented and analyzed. In addition, capacitive coupling along bends provides coherent spin-spin interaction, including between otherwise disconnected nanotubes, completing a universal set of one- and two-qubit gates.......We investigate combined effects of spin-orbit coupling and magnetic field in carbon nanotubes containing one or more bends along their length. We show how bends can be used to provide electrical control of confined spins, while spins confined in straight segments remain insensitive to electric...
Hamiltonian system for orthotropic plate bending based on analogy theory
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
Based on analogy between plane elasticity and plate bending as well as variational principles of mixed energy, Hamiltonian system is further led to orthotropic plate bending problems in this paper. Thus many effective methods of mathematical physics such as separation of variables and eigenfunction expansion can be employed in orthotropic plate bending problems as they are used in plane elasticity. Analytical solutions of rectangular plate are presented directly, which expands the range of analytical solutions. There is an essential distinction between this method and traditional semi-inverse method. Numerical results of orthotropic plate with two lateral sides fixed are included to demonstrate the effectiveness and accuracy of this method.
A Numerical Study of the Spring-Back Phenomenon in Bending with a Rebar Bending Machine
Chang Hwan Choi; Lawrence Kulinsky; Joon Soo Jun; Jin Ho Kim
2014-01-01
Recently, the rebar bending methodology started to change from field processing to utilizing rebar bending machines at plant sites prior to transport to the construction locations. Computerized control of rebar plant bending machines provides more accurate and faster bending of rebars than the low quality inefficient field processing alternative. The bending process involves plastic deformation of rebars, where bending stress beyond the yield point of the material is applied. When the bending...
International Nuclear Information System (INIS)
The problem of moment formation in metallic systems lies at the interface of localized and itinerant magnetism. The phenomena observed correspond to destruction rather than to formation of spin-correlations. They give rise to the progression from localized ground states through Kondo and mixed-valence behavior to itinerant magnetic or non-magnetic systems. Somewhere in the progression superconductivity can occur in the presence of f-moments. This conference presents information on the following topics: neuron inelastic scattering as a probe of moments in metallic systems; cyclotron resonance and relaxation of hot charge carriers; orbital effects in actinide systems; theory of elementary excitations in intermediate valence materials: phenomena involving magnetic moment suppresion; and superconducting ground state of a strongly interacting electron system: UBe13
International Nuclear Information System (INIS)
It is shown that the method of eliminating the statistical fluctuations from event-by-event analysis proposed recently by Fu and Liu can be rewritten in a compact form involving the generalized factorial moments. (author)
International Nuclear Information System (INIS)
In the standard electroweak model, the parity violating electron-nucleus interaction associated with the hadronic axial neutral current is accidentally suppressed and, as a consequence, dominated by the electron interaction with the nuclear anapole moment, which describes the effect of the parity violating nuclear forces on the nucleus electromagnetic current. In order to give a physical picture of the nuclear anapole moment, we present here a simple relation between the anapole moment and the nuclear magnetization. From this relation it follows that the computation of the anapole moment can be reduced to that of one-body operators. The basic tool is a unitary transformation which eliminates the one-body parity violating potential from the nuclear Hamiltonian. The result obtained by our approach and the approaches followed by other groups are in rough quantitative agreement with the recent measurement performed in 133Cs at Boulder. (author)
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
Abig fish jumped out of the crystal clear water in a mountain creek.In a split second a bear splashed into the water charging at the fish.The exciting moment was captured by a Rollei camera and displayed
Modeling of a cracked beam section under bending
International Nuclear Information System (INIS)
Numerical simulations are widely used to study the dynamical behaviour of turbines cracked shaft as this event is rare and then doesn't enable to have an useful industrial feedback. A new method, which enables to calculate the constitutive law of a cracked beam subjected to bending was previously proposed. Based on three-dimensional computations taking into account the unilateral contact between both lips of the crack, it consists in defining a (non-linear) behaviour relation between the bending moment applied to the cracked section and the resulting field of displacements, compatible with the beam theory so that it can be used in rotor-dynamics software. The aim of this paper is to complete this first model by adding shear effects. For some crack geometries, a simpler model can be derived, based on the recognition that bending moments and shear forces are uncoupled and the dependence of the behaviour law with respect to the shear forces becomes linear. Developments have been achieved in this case and some results of the validation tests are shown. (authors)
International Nuclear Information System (INIS)
In chiral bag model an expression is obtained for the quark wave functions with account of color and pion interaction of quarks. The quadrupole moments of nonstrange hadrons are calculated. Quadrupole moment of nucleon isobar is found to be Q(Δ)=-6.3x10-28 esub(Δ)(cm)sup(2). Fredictions of the chiral bag model are in strong disagreement with the non-relativistic quark model
Nuclear fuels accounting interface: River Bend experience
Energy Technology Data Exchange (ETDEWEB)
Barry, J.E.
1986-01-01
This presentation describes nuclear fuel accounting activities from the perspective of nuclear fuels management and its interfaces. Generally, Nuclear Fuels-River Bend Nuclear Group (RBNG) is involved on a day-by-day basis with nuclear fuel materials accounting in carrying out is procurement, contract administration, processing, and inventory management duties, including those associated with its special nuclear materials (SNM)-isotopics accountability oversight responsibilities as the Central Accountability Office for the River Bend Station. As much as possible, these duties are carried out in an integrated, interdependent manner. From these primary functions devolve Nuclear Fuels interfacing activities with fuel cost and tax accounting. Noting that nuclear fuel tax accounting support is of both an esoteric and intermittent nature, Nuclear Fuels-RBNG support of developments and applications associated with nuclear fuel cost accounting is stressed in this presentation.
Nuclear fuels accounting interface: River Bend experience
International Nuclear Information System (INIS)
This presentation describes nuclear fuel accounting activities from the perspective of nuclear fuels management and its interfaces. Generally, Nuclear Fuels-River Bend Nuclear Group (RBNG) is involved on a day-by-day basis with nuclear fuel materials accounting in carrying out is procurement, contract administration, processing, and inventory management duties, including those associated with its special nuclear materials (SNM)-isotopics accountability oversight responsibilities as the Central Accountability Office for the River Bend Station. As much as possible, these duties are carried out in an integrated, interdependent manner. From these primary functions devolve Nuclear Fuels interfacing activities with fuel cost and tax accounting. Noting that nuclear fuel tax accounting support is of both an esoteric and intermittent nature, Nuclear Fuels-RBNG support of developments and applications associated with nuclear fuel cost accounting is stressed in this presentation
Effect of bending pattern on finger joint bending strength
Directory of Open Access Journals (Sweden)
Džinčić Igor
2012-01-01
Full Text Available Limited information is available on end gluing hardwoods in contrast to softwoods, which have been extensively investigated. The objective of this study was to examine the influence of bending patern on bending strength of finger jointed beech wood. In structural uses finger jointing is finally the major method to end joint timber for the production of glue-laminated elements. There are no bending strength experimental results for finger-jointed hardwoods for investigations conducted in Serbia. Two finger jointed profiles were studied in accordance with DIN68140. The finger joints were made by side and by face of beam. Length jointed samples were loaded at the side and in the face. The obtained results led to the conclusion that the direction of load, gluing surface and the position of joint influence on the strength of continued longitudinal beams.
Development of 3-COMPONENT Force-Moment Balance for Low Speed Water Tunnel
Lee, C. S.; Wong, N. L.; Srigrarom, S.; Nguyen, N. T.
An effort is made to develop a new 3-component force-moment balance, which is capable of measuring lift force, drag force and pitching moment of a model mounted in the water tunnel. The concept used in the balance design is the bending- beam principle. The forces acting on the spring element cause strains on its surface, which are measured by strain gauges. Since strain yielded by the axial force is usually very small, therefore it is not practical to measure axial force using strain gauge directly to sense the strain in axial direction. The main idea of the new balance design is to translate all desired forces (lift and drag) in such a way that they yield bending strain at selected strain-gauge station. This is done by using a bending balance geometry. Under this apparatus, the model wing is mounted at one of its end to the bending balance. The corresponding Lift, Drag forces and Pitching moment are translated into moments at the other end of the balance, and can be measured from sets of strain gauges in bending mode (twisting mode for pitching moment). Example readings are presented in this paper.
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
A new kind of bend sensor is introduced.It can be used to detect the bend angle of an object or inclination between two objects.It has characteristics of small size, lightweight, high reliability, fine flexibility and plasticity.When this bend sensor is used with a proper converting circuit, it can implement dynamic measuring the bend angle of an object conveniently.The application of the bend sensor in dataglove is also described.
Moments in particle-in-cell simulations
International Nuclear Information System (INIS)
The moment equations that form the basis of the BEDLAM simulation code can also be used as a check on Particle-In-Cell (PIC) simulations. Moments can be computed as sums over the macroparticles used in the PIC simulations. These moments should satisfy the moment equations if the simulation is valid. A check has been done to sixth order for two cases: the RFQRZP code, which simulated a radio-frequency quadrupole (RFQ) linac, and the BEAMTRACE code, which simulated the final focusing system in a heavy ion fusion facility. Because our modified PIC codes were able to compute moments that satisfied the correct moment equations, we were able to use our modified version of RFQRZP, which we called RFQMOM, to work on another problem. Every moment simulation code has to include some truncation approximation. The error of this approximation can be determined by RFQMOM before actually writing the moment code. As an example, we investigated the accuracy of the truncation approximation that is used in the BEDLAM code. 6 refs., 4 figs
International Nuclear Information System (INIS)
During the first experiment of the experimental group E21 - behaviour of crack growth of piping components at operating pressure and cyclic bending load in a corrosive medium - performed within phase III of the HDR Safety Program a pipe bend made of ferritic material 20 MnMoNi 5 5 was the object investigated. During the test incipient cracks were generated by cyclic bending on the inner surface around the bend flanks. In various phases of the test characterized by sinoidal and sawtooth modes of loading and different load frequencies (1 cycle per minute and 1 cycle per 15 minutes) the cracks were further extended. At the end of the phase cyclic testing the maximum crack depth of the macrocrack embedded in a crack field was approx. 21 mm. In the final load test with monotonously rising bending moment the pipe bend failed in the form of a leak. (author)
International Nuclear Information System (INIS)
The bending of rod fuel elements in gas-cooled fast reactors under the action of temperature gradients radiation-induced swelling non-uniform over the perimeter of fuel cans is evaluated. It is pointed out that the radiation-induced swelling gives the main contribution to the bending of fuel elements. Calculated data on the bending of the corner fuel element in the assembly of the fast reactor with dissociating gas coolant are given. With the growth of temperature difference over the perimeter, the bending moment and deformation increase, resulting in the increase of axial stresses. The obtained data give the basis for accounting the stresses connected with thermal and radiation bending when estimating serviceability of fuel elements in gas cooled fast reactors. Fuel element bending must be also taken into account when estimating the thermal hydrualic properties
Bending characteristics of resin concretes
Directory of Open Access Journals (Sweden)
Ribeiro Maria Cristina Santos
2003-01-01
Full Text Available In this research work the influence of composition and curing conditions in bending strength of polyester and epoxy concrete is analyzed. Various mixtures of resin and aggregates were considered in view of an optimal combination. The Taguchi methodology was applied in order to reduce the number of tests, and in order to evaluate the influence of various parameters in concrete properties. This methodology is very useful for the planning of experiments. Test results, analyzed by this methodology, shown that the most significant factors affecting bending strength properties of resin concretes are the type of resin, resin content and charge content. An optimal formulation leading to a maximum bending strength was achieved in terms of material parameters.
Characterization of Human Rib Biomechanical Responses due to Three-Point Bending.
Kalra, Anil; Saif, Tal; Shen, Ming; Jin, Xin; Zhu, Feng; Begeman, Paul; Yang, King H; Millis, Scott
2015-11-01
In the elderly population, rib fracture is one of the most common injuries sustained in motor vehicle crashes. The current study was conducted to predict the biomechanical fracture responses of ribs with respect to age, gender, height, weight and percentage of ash content. Three-point bending experiments were conducted on 278 isolated rib samples extracted from 82 cadaver specimens (53 males and 29 females between the ages of 21 and 87 years) for 6th and 7th levels of ribs. Statistical analyses were carried out to identify differences based on age and gender. It was found that, in comparison to males, females had significantly lower values for maximum bending moments, slopes of bending moment-angle curves, and average cortical-bone thickness (pcrash conditions. Hence, rib-material properties, which are dependent on strain rate, and are needed for wholebody finite element models representing different populations, still require more research. PMID:26660742
Temporal Moments in Hydrogeophysics
Pollock, D.; Cirpka, O. A.
2007-12-01
Electrical Resistivity Tomography (ERT) has been tested as monitoring tool for salt-tracer experiments by various authors. So far, the analysis of such experiments has been done by a two-step procedure [Kemna et al., 2002; Vanderborght et al., 2005; Singha and Gorelick, 2005]. In the first step, classical geophysical inversion methods have been used to infer the distribution of electrical conductivity, which is transferred to an estimated concentration distribution of the tracer. Subsequently, the inferred concentration images were analyzed to estimate hydraulic quantities such as the velocity distribution. This approach has two disadvantages: The concentration distribution is reconstructed with a high spatial resolution, but the estimate is uncertain, and the estimation uncertainty is spatially correlated. These correlated uncertainties should be accounted for in the estimation of hydraulic conductivity from concentration values. The latter, unfortunately, is not practical because the reconstructed data sets are very large. The geophysical inversion is not enforced to be in agreement with basic hydromechanical constraints. E.g., Singha and Gorelick [2005] observed an apparent loss of solute mass when using ERT as monitoring tool. We propose considering the temporal moments of potential-difference time series. These temporal moments depend on temporal moments of concentration, which have already been used in the inference of hydraulic- conductivity distributions (Cirpka and Kitanidis, 2000). In our contribution, we present the complete set of equations leading from hydraulic conductivity via hydraulic heads, velocities, temporal moments of concentrations to temporal moments of potential differences for given flow and transport boundary conditions and electrode configurations. We also present how the sensitivity of temporal moments of potential differences on the hydraulic conductivity field can be computed without the need of storing intermediate sensitivities
Combustion engineering: steam generator tube bending practices
International Nuclear Information System (INIS)
The tube bending practices and procedures employed by Combustion Engineering (CE), when bending inconel tubing is discussed. CE has two different type tube geometries in the steam generator. The innermost tubes are 1800 U-bends while the majority of the tubes have two (2) 900 bends with a straight leg between these 900 bends. The first 18 rows have U-bends (2 1/2'' to 11''R), while the remaining tubes have the double 900 geometry. All double 900 bends are bent to a 10'' radius. This presentation will address the following important parameters necessary to achieve a high quality bent tube: fabrication requirements at the tube mill; tube bending equipment; tube bending operation; inspection and final preparation; and packaging
Binomial moment equations for stochastic reaction systems.
Barzel, Baruch; Biham, Ofer
2011-04-15
A highly efficient formulation of moment equations for stochastic reaction networks is introduced. It is based on a set of binomial moments that capture the combinatorics of the reaction processes. The resulting set of equations can be easily truncated to include moments up to any desired order. The number of equations is dramatically reduced compared to the master equation. This formulation enables the simulation of complex reaction networks, involving a large number of reactive species much beyond the feasibility limit of any existing method. It provides an equation-based paradigm to the analysis of stochastic networks, complementing the commonly used Monte Carlo simulations. PMID:21568538
Hormonal regulation of gravitropic bending
Hu, X.; Cui, D.; Xu, X.; Hu, L.; Cai, W.
Gravitropic bending is an important subject in the research of plant Recent data support the basics of the Cholodny-Went hypothesis indicating that differential growth in gravitropism is due to redistribution of auxin to the lower sides of gravistimulated roots but little is known regarding the molecular details of such effects So we carried a series of work surround the signals induced by auxin end center We found the endogenous signaling molecules nitric oxide NO and cGMP mediate responses to gravistimulation in primary roots of soybean Glycine max Horizontal orientation of soybean roots caused the accumulation of both NO and cGMP in the primary root tip Fluorescence confocal microcopy revealed that the accumulation of NO was asymmetric with NO concentrating in the lower side of the root Auxin induced NO accumulation in root protoplasts and asymmetric NO accumulation in root tips Gravistimulation NO and auxin also induced the accumulation of cGMP a response inhibited by removal of NO or by inhibitors of guanylyl cyclase compounds that also reduced gravitropic bending Asymmetric NO accumulation and gravitropic bending were both inhibited by an auxin transport inhibitor and the inhibition of bending was overcome by treatment with NO or 8-bromo-cGMP a cell-permeable analog of cGMP These data indicate that auxin-induced NO and cGMP mediate gravitropic curvature in soybean roots From Hu et al Plant Physiol 2005 137 663-670 The asymmetric distribution of auxin plays a fundamental role in plant gravitropic bending
International Nuclear Information System (INIS)
I would like to discuss the problem of a neutrino magnetic moment which is of interest since it deals with the probable time anticorrelation of the solar v flux with the Sun magnetic activity. (author). 19 refs, 2 figs, 1 tab
International Nuclear Information System (INIS)
The statistical characteristics of a spatial region visited by a spherical Brownian particle during time t (Wiener sausage) are investigated. The expectation value and dispersion of this quantity are obtained for a space of arbitrary dimension. In the one-dimensional case the distribution of probability density and the moments of any order are determined for this quantity
Goodrow, Mary Ellen
2000-01-01
Details how an unplanned activity involving spinning wool presented a teachable moment for children in a family child care setting. Notes how activities related to farming, spinning wool, and using wool cloth resulted from following the children's lead. Concludes that everyday activities provide opportunities to listen to children, learn about…
An online database of nuclear electromagnetic moments
Mertzimekis, T. J.; Stamou, K.; Psaltis, A.
2016-01-01
Measurements of nuclear magnetic dipole and electric quadrupole moments are considered quite important for the understanding of nuclear structure both near and far from the valley of stability. The recent advent of radioactive beams has resulted in a plethora of new, continuously flowing, experimental data on nuclear structure - including nuclear moments - which hinders the information management. A new, dedicated, public and user friendly online database
Theory of nuclear magnetic moments - LT-35
International Nuclear Information System (INIS)
The purpose of these notes is to give an account of some attempts at interpreting the observed values of nuclear magnetic moments. There is no attempt at a complete summary of the field as that would take much more space than is used here. In many cases the arguments are only outlined and references are given for those interested in further details. A discussion of the theory of nuclear magnetic moments necessitates many excursions into the details of the nuclear models because the magnetic moments have a direct bearing on the validity of these models. However the main emphasis here is on those features which tend to explain the magnetic moments and other evidence is not discussed unless it has a direct bearing on the problem. In the first part of the discussion the Shell Model of the nucleus is used, as this model seems to correlate a large body of data relating to the heavier nuclei. Included here are the modifications proposed to explain the fact that the experimental magnetic moments do not fit quantitatively with the exact predictions of the Shell Model. The next sections deal with some of the more drastic modifications introduced to explain the large nuclear quadrupole moments and the effect of these modifications on the magnetic moments. Finally we turn to more detailed investigations of the light nuclei, in particular the - Conjugate nuclei. (author)
Bending Boundary Layers in Laminated-Composite Circular Cylindrical Shells
Nemeth, Michael P.; Smeltzer, Stanley S., III
2000-01-01
A study of the attenuation of bending boundary layers in balanced and unbalanced, symmetrically and unsymmetrically laminated cylindrical shells is presented for nine contemporary material systems. The analysis is based on the linear Sanders-Koiter shell equations and specializations to the Love-Kirchhoff shell equations and Donnell's equations are included. Two nondimensional parameters are identified that characterize the effects of laminate orthotropy and anisotropy on the bending boundary-layer decay length in a very general manner. A substantial number of structural design technology results are presented for a wide range of laminated-composite cylinders. For all laminates considered, the results show that the differences between results obtained with the Sanders-Koiter shell equations, the Love-Kirchhoff shell equations, and Donnell's equations are negligible. The results also show that the effect of anisotropy in the form of coupling between pure bending and twisting has a negligible effect on the size of the bending boundary-layer decay length of the balanced, symmetrically laminated cylinders considered. Moreover, the results show that coupling between the various types of shell anisotropies has a negligible effect on the calculation of the bending boundary-layer decay length in most cases. The results also show that, in some cases, neglecting the shell anisotropy results in underestimating the bending boundary-layer decay length and, in other cases, results in an overestimation.
Bending of light in quantum gravity.
Bjerrum-Bohr, N E J; Donoghue, John F; Holstein, Barry R; Planté, Ludovic; Vanhove, Pierre
2015-02-13
We consider the scattering of lightlike matter in the presence of a heavy scalar object (such as the Sun or a Schwarzschild black hole). By treating general relativity as an effective field theory we directly compute the nonanalytic components of the one-loop gravitational amplitude for the scattering of massless scalars or photons from an external massive scalar field. These results allow a semiclassical computation of the bending angle for light rays grazing the Sun, including long-range ℏ contributions. We discuss implications of this computation, in particular, the violation of some classical formulations of the equivalence principle. PMID:25723201
Wood bending using microwave heating
International Nuclear Information System (INIS)
This article presents a new technique of wood bending where microwave irradiation is used to heat and soften wet wood specimens. Compared to the traditional steaming procedure, this procedure offers many advantages : (i) as the heating occurs inside the specimen, complete softening is obtained very quickly; (ii) temperature can be easily controlled in order to obtain the best processing conditions; (iii) the benefit will be especially big in the case of large specimens whose pretreatment may take hours with steaming; (iv) in general, the applicability of wood bending is enlarged, i.e. new wood species and specimens with lower quality can endure larger deformations with a reduced loss. In the case where drastic strain levels are required, the forming and setting operations should be done inside the microwave oven, in order to take advantage of the additional ''mechano-sorptive'' flexibility appearing when wood dries under load
Gonzalez-Martin, Gustavo R; Gonzalez, Javier G
2004-01-01
The magnetic moment of the proton is calculated using a geometric unified theory. The geometry determines a generalized Pauli equation showing anomalous terms due to the triplet proton structure. The theoretical result gives a bare anomalous Lande gyromagnetic g-factor close to the experimental value. The necessary radiative corrections should be included in the actual theoretical dressed value. The first order correction raises the value to 2(2.7796). Similarly we obtain for the neutron gyromagnetic g-factor the value 2(1.9267).
Solar rotation gravitational moments
Directory of Open Access Journals (Sweden)
A. Ajabshirizadeh
2005-09-01
Full Text Available Gravitational multipole moments of the Sun are still poorly known. Theoretically, the difficulty is mainly due to the differential rotation for which the velocity rate varies both on the surface and with the depth. From an observational point of view, the multipole moments cannot be directly measured. However, recent progresses have been made proving the existence of a strong radial differential rotation in a thin layer near the solar surface (the leptocline. Applying the theory of rotating stars, we will first compute values of J2 and J4 taking into account the radial gradient of rotation, then we will compare these values with the existing ones, giving a more complete review. We will explain some astrophysical outcomes, mainly on the relativistic Post Newtonian parameters. Finally we will conclude by indicating how space experiments (balloon SDS flights, Golf NG, Beppi-Colombo, Gaia... will be essential to unambiguously determine these parameters.
Takahashi, Asami; Ishigure, Takaaki
2015-02-01
We fabricate low-loss graded index (GI) circular core multimode polymer optical waveguides with 90o bending and demonstrate low bending loss even if the bend radius is as small as 1 mm. In the several fabrication methods for GI-core polymer waveguides already proposed, we adopt the "Mosquito method" that utilize a microdispenser because the Mosquito method makes it possible to fabricate waveguides directly on board at desired places on a printed circuit board, and to draw various patterns of cores including curves. However, in the waveguides including such curved cores, the additional transmission loss due to the bending (bending loss) is a concern. Thus, we characterize the fabricated GI-core polymer waveguides with bending: using two kinds of cladding monomer with different refractive indexes for fabricating waveguides with bending. We found when the NA of waveguides was as high as 0.35, no additional loss due to bending was observed even if the bending radius is as small as 1 mm. The core diameter of the fabricated waveguides is 50 μm, and it is possible to further decrease the bending loss in the waveguides with smaller core diameter. Furthermore, utilizing the Mosquito method, we fabricate waveguides with not only horizontally curved cores but also vertically curved ones. Waveguides with vertically curved cores could make it possible to realize three-dimensionally optical wiring applicable to on-board optical interconnects.
Energy Technology Data Exchange (ETDEWEB)
Channell, P.J.; Healy, L.M.; Lysenko, W.P.
1985-10-01
This paper describes the status of BEDLAM and presents the results of some tests. We simulated a section of radio-frequency quadrupole (RFQ) linac, neglecting space charge, to test the new code. Agreement with a Particle-In-Cell (PIC) simulation was excellent. We also verified that the fourth-order solution is more accurate than the second-order solution, which indicates the convergence of the method. We believe these results justify the continued development of moment simulation codes.
Redefining the political moment
Directory of Open Access Journals (Sweden)
James Arvanitakis
2011-07-01
Full Text Available On 16 February 2003, more than half a million people gathered in Sydney, Australia, as part of a global anti-war protest aimed at stopping the impending invasion of Iraq by the then US Administration. It is difficult to estimate how many millions marched on the coordinated protest, but it was by far the largest mobilization of a generation. Walking and chanting on the streets of Sydney that day, it seemed that a political moment was upon us. In a culture that rarely embraces large scale activism, millions around Australian demanded to be heard. The message was clear: if you do not hear us, we would be willing to bring down a government. The invasion went ahead, however, with the then Australian government, under the leadership of John Howard, being one of the loudest and staunchest supporters of the Bush Administrations drive to war. Within 18 months, anti-war activists struggled to have a few hundred participants take part in anti-Iraq war rallies, and the Howard Government was comfortably re-elected for another term. The political moment had come and gone, with both social commentators and many members of the public looking for a reason. While the conservative media was often the focus of analysis, this paper argues that in a time of late capitalism, the political moment is hollowed out by ‘Politics’ itself. That is to say, that formal political processes (or ‘Politics’ undermine the political practices that people participate in everyday (or ‘politics’. Drawing on an ongoing research project focusing on democracy and young people, I discuss how the concept of ’politics‘ has been destabilised and subsequently, the political moment has been displaced. This displacement has led to a re-definition of ‘political action’ and, I argue, the emergence of a different type of everyday politics.
How Does The Bone Shaft Geometry Affect its Bending Properties?
Directory of Open Access Journals (Sweden)
Kaveh P. Saffar
2009-01-01
Full Text Available In this research, ten fresh specimens of sheep tibiae were provided from slaughtered animals. Whole bone specimens were loaded in three-point bending according to standard wet bone test protocols. Mechanical properties were determined and compared with the results which were obtained from two dry bone tests. The results showed that fracture bending moment and bone extrinsic stiffness had significant relations with fracture cross-section dependent parameters (i.e., cross-section area and area moment of inertia. Where, fracture energy and ultimate strength did not have such a relation with these parameters. Finite element modeling of bone shaft was made with simplified geometry (neglecting cross-section variations along bone shaft in two steps: First, by elliptical cross-section and second, by circular cross-section, assuming linear elastic and isotropic properties for the specimens. Elastic (Youngs modulus and fracture load, evaluated from curves obtained from tests, were applied to the finite element model and close results of maximum stress in both test specimen and first (elliptical cross-section model showed up. There was an average difference of about 2% between ultimate strength of wet bone specimens and maximum (tensile stress occurred in the elliptical models. However, this value for circular models was about 16%.
Higher Moments of Weighted Integrals of Non-Gaussian Fields
DEFF Research Database (Denmark)
Mohr, Gunnar
In general , the exact probability distribution of a definite non-Gaussian random field is not known. Some information about this unknown distribution can be obtained from the 3rd and 4th moment of the integral. Approximations to these moments are calculated by a numerical technique based on...... known moments (including mixed moments) as fx log-normal variables or polynomials of standard Gaussian variables. This sceme is used when calculating the moments of the integral (and eventually approximating the integral by a Winterstein approximation)....
Stress distribution in elbow due to external moments using finite-element methodology
International Nuclear Information System (INIS)
Curved pipes or elbows are commonly used in piping systems to provide flexibility and changes in direction in nuclear power plants, fossil fuel power plants, petrochemical and other plants. Elbows are also sources of stress intensification. Therefore, the Codes require a stress intensification factor (SIF) to be applied to stress at elbow computed by elementary bending theory. In this paper meridional (tangential) and circumferential (hoop) variations of stresses in elbows are obtained by using finite element method for external moment loadings. The finite element models considered in this study included elbows of various sizes and wall thicknesses as well as long and short radii elbows. The results are compared with the available data and Code SIF values. The SIF values for mid and end sections of elbow are also compared and presented
Paul Callaghan luminous moments
Callaghan, Paul
2013-01-01
Acknowledged internationally for his ground-breaking scientific research in the field of magnetic resonance, Sir Paul Callaghan was a scientist and visionary with a rare gift for promoting science to a wide audience. He was named New Zealander of the Year in 2011. His death in early 2012 robbed New Zealand of an inspirational leader. Paul Callaghan: Luminous Moments brings together some of his most significant writing. Whether he describes his childhood in Wanganui, reflects on discovering the beauty of science, sets out New Zealand's future potential or discusses the experience of fa
International Nuclear Information System (INIS)
To mark the one hundredth anniversary of the discovery of the electron by J.J. Thomson, this article, part of a series, looks at low energy electron experiments which show promise of developing our understanding of elementary particle physics beyond the standard model and quantum electrodynamics. Study of electric dipole moments, time-reversal and supersymmetry at the Sussex centre for optical and atomic physics is described. Calculations to determine electron spin in YbF have been undertaken at 30Gvm sup - sup 1. 4 figs
Redefining the political moment
James Arvanitakis
2011-01-01
On 16 February 2003, more than half a million people gathered in Sydney, Australia, as part of a global anti-war protest aimed at stopping the impending invasion of Iraq by the then US Administration. It is difficult to estimate how many millions marched on the coordinated protest, but it was by far the largest mobilization of a generation. Walking and chanting on the streets of Sydney that day, it seemed that a political moment was upon us. In a culture that rarely embraces large scale activ...
Giammanco, Chiara H; Kramer, Patrick L; Yamada, Steven A; Nishida, Jun; Tamimi, Amr; Fayer, Michael D
2016-01-28
The population relaxation of carbon dioxide dissolved in the room temperature ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EmimNTf2) was investigated using polarization-selective ultrafast infrared pump-probe spectroscopy and two-dimensional infrared (2D IR) spectroscopy. Due to the coupling of the bend with the asymmetric stretch, excitation of the asymmetric stretch of a molecule with a thermally populated bend leads to an additional peak, a hot band, which is red-shifted from the main asymmetric absorption band by the combination band shift. This hot band peak exchanges population with the main peak through the gain and loss of bend excitation quanta. The isotropic pump-probe signal originating from the unexcited bend state displays a fast, relatively small amplitude, initial growth followed by a longer time scale exponential decay. The signal is analyzed over its full time range using a kinetic model to determine both the vibrational lifetime (the final decay) and rate constant for the loss of the bend energy. This bend relaxation manifests as the fast initial growth of the stretch/no bend signal because the hot band (stretch with bend) is "over pumped" relative to the ground state equilibrium. The nonequilibrium pumping occurs because the hot band has a larger transition dipole moment than the stretch/no bend peak. The system is then prepared, utilizing an acousto-optic mid-infrared pulse shaper to cut a hole in the excitation pulse spectrum, such that the hot band is not pumped. The isotropic pump-probe signal from the stretch/no bend state is altered because the initial excited state population ratio has changed. Instead of a growth due to relaxation of bend quanta, a fast initial decay is observed because of thermal excitation of the bend. Fitting this curve gives the rate constant for thermal excitation of the bend and the lifetime, which agree with those determined in the pump-probe experiments without frequency
Directory of Open Access Journals (Sweden)
Marc eWittmann
2011-10-01
Full Text Available It has been suggested that perception and action can be understood as evolving in temporal epochs or sequential processing units. Successive events are fused into units forming a unitary experience or ‘psychological present’. Studies have identified several temporal integration levels on different time scales which are fundamental for our understanding of behaviour and subjective experience. In recent literature concerning the philosophy and neuroscience of consciousness these separate temporal processing levels are not always precisely distinguished. Therefore, empirical evidence from psychophysics and neuropsychology on these distinct temporal processing levels is presented and discussed within philosophical conceptualizations of time experience. On an elementary level, one can identify a functional moment, a basic temporal building block of perception in the range of milliseconds that defines simultaneity and succession. Below a certain threshold temporal order is not perceived, individual events are processed as co-temporal. On a second level, an experienced moment, which is based on temporal integration of up to a few seconds, has been reported in many qualitatively different experiments in perception and action. It has been suggested that this segmental processing mechanism creates temporal windows that provide a logistical basis for conscious representation and the experience of nowness. On a third level of integration, continuity of experience is enabled by working-memory in the range of multiple seconds allowing the maintenance of cognitive operations and emotional feelings, leading to mental presence, a temporal window of an individual’s experienced presence.
Garment-Integrated Bend Sensor
Directory of Open Access Journals (Sweden)
Guido Gioberto
2014-09-01
Full Text Available Garment-integrated sensors equip clothes with a smart sensing capability, while preserving the comfort of the user. However, this benefit can be to the detriment of sensing accuracy due to the unpredictability of garment movement (which affects sensor positioning and textile folds (which can affect sensor orientation. However, sensors integrated directly into garments or fabric structures can also be used to detect the movement of the garment during wearing. Specifically, a textile bend sensor could be used to sense folds in the garment. We tested a garment-integrated stitched sensor for five types of folds, stitched on five different weights of un-stretchable denim fabric and analyzed the effects of fold complexity and fabric stiffness, under un-insulated and insulated conditions. Results show that insulation improves the linearity and repeatability of the sensor response, particularly for higher fold complexity. Stiffer fabrics show greater sensitivity, but less linearity. Sensor response amplitude is larger for more complex fold geometries. The utility of a linear bending response (insulated and a binary shorting response (un-insulated is discussed. Overall, the sensor exhibits excellent repeatability and accuracy, particularly for a fiber-based, textile-integrated sensor.
Ductile failure of pipes with defects under combined pressure and bending
International Nuclear Information System (INIS)
The main part of the experimental programme was carried out on 3.5'' diam. pipes with a wall thickness of 0.064''. Various lengths of defect were assessed but only two depths, 0.044'' and 0.060''. Some full penetration defect tests were carried out under bending loading. The defects were 0.012'' wide and nominally flat bottomed. The tensile properties of the pipes were determined by taking specimens from each of the tubes. The pipes were exposed to pressure only test, bending only test and combined bending and pressure test. The results are given in tables. The observations led to the postulation of a design rule relating to the effect of defect in pipes under combined internal pressure and bending. It applies only to ductile situations in which the mode of failure is by a collapse mechanism: If the failure of a pipe containing an axial defect occurs by plastic collapse then provided the bending moment does not exceed half that for collapse due to bending alone, it will have a negligible effect on the failure pressure. (J.B.)
Directory of Open Access Journals (Sweden)
Kupavtsev Vladimir Vladimirovich
2013-02-01
Full Text Available In the article, the author proposes an original method of identification of upper and lower bounds of critical values of loading parameters in respect of three stability problems for a non-uniformly compressed rectilinear one-span elastic rod with a varying longitudinal bending stiffness value.Initial variational formulations of stability problems under consideration are presented through internal bending moments that emerge at the moment of the rod stability loss and that satisfy uniform boundary conditions rather than additional integral conditions. The author has obtained forms of the bending moment and respective loading parameter values in case of the rod equilibrium bifurcation in the basic problem of stability of an elastic rectilinear rod with a constant cross section, compressed by longitudinal forces at the rod ends.The calculation of the lower bound is reduced to determination of the greatest eigenvalues for the matrices presented in the form of modular matrices of the second order with the elements expressed through the integrals of available forms of bending moments. The calculation of the upper bound is reduced to determination of the greatest eigenvalue for the matrix that almost coincides with one of modular matrices.Рассмотрены задачи устойчивости упругих неоднородно сжатых однопролетных стержней, вариационные формулировки критического значения параметра нагружения в которых выражены через возникающие при бифуркации изгибающие моменты без дополнительных условий. Вычисление оценок снизу и сверху для искомого параметра нагружения сведено к нахождению наибольшего собственного числа матриц,
Qualification of a motorized scanner for feeder bend inspection
International Nuclear Information System (INIS)
This paper will review the qualification of the Inspection System based on the motorized feeder bend-cracking crawler designed by IREQ and the inspection procedure COG-JP-4107- V43 developed by Hydro-Quebec and New-Brunswick Power. The mechanization of the inspection was necessary to address new concerns found after the discovery in 2003 of cracks on second bends and also the finding that several removed cracked bends had additional incipient OD cracks on the extrados. This document describes the apparatus, procedure and test-results that support the adequacy of the inspection system to meet the inspection specifications and the CSA N285.4 Standard. A review of the qualification process is included. A particular aspect of the work is the emphasis set on detecting OD flaws. Field results from PLGS and G-2 outages will be addressed. (author)
Elastic bending modulus of monolayer graphene
International Nuclear Information System (INIS)
An analytic formula is derived for the elastic bending modulus of monolayer graphene based on an empirical potential for solid-state carbon atoms. Two physical origins are identified for the non-vanishing bending stiffness of the atomically thin graphene sheet, one due to the bond-angle effect and the other resulting from the bond-order term associated with the dihedral angles. The analytical prediction compares closely with ab initio energy calculations. Pure bending of graphene monolayers into cylindrical tubes is simulated by a molecular mechanics approach, showing slight nonlinearity and anisotropy in the tangent bending modulus as the bending curvature increases. An intrinsic coupling between bending and in-plane strain is noted for graphene monolayers rolled into carbon nanotubes. (fast track communication)
Elastic bending modulus of monolayer graphene
Energy Technology Data Exchange (ETDEWEB)
Lu Qiang; Huang Rui [Department of Aerospace Engineering and Engineering Mechanics, University of Texas, Austin, TX 78712 (United States); Arroyo, Marino [Department of Applied Mathematics 3, LaCaN, Universitat Politecnica de Catalunya (UPC), Barcelona 08034 (Spain)
2009-05-21
An analytic formula is derived for the elastic bending modulus of monolayer graphene based on an empirical potential for solid-state carbon atoms. Two physical origins are identified for the non-vanishing bending stiffness of the atomically thin graphene sheet, one due to the bond-angle effect and the other resulting from the bond-order term associated with the dihedral angles. The analytical prediction compares closely with ab initio energy calculations. Pure bending of graphene monolayers into cylindrical tubes is simulated by a molecular mechanics approach, showing slight nonlinearity and anisotropy in the tangent bending modulus as the bending curvature increases. An intrinsic coupling between bending and in-plane strain is noted for graphene monolayers rolled into carbon nanotubes. (fast track communication)
Bending magnets design of cERL
International Nuclear Information System (INIS)
We are now constructing Compact Energy Recovery Linac (cERL) to start commissioning in March of 2013. We started constructing 35MeV, 10mA, 1loop design, and after step by step reinforcement, we will complete 245MeV, 100mA, and 2loop facility of cERL. We use 2 type bending magnets, sector type magnet and branch bend. Both magnets are trapezoid shape and bending radiuses are 1m, bending angles are 45degree. After constructing second loop, we use the branch bend to separate low energy electron to first loop and high energy electron to second loop. We report these two type bending magnets design of cERL. (author)
Space charge effects in a bending magnet system
International Nuclear Information System (INIS)
In order to examine problems and phenomena associated with space charge in a beam bending system, the beam dynamics code HICURB has been written. Its principal features include momentum variations, vertical and horizontal envelope dynamics coupled to the off-axis centroid, curvature effect on fields, and images. Preliminary results for an achromatic lattice configuration are presented
Minimum Membrane Bending Energies of Fusion Pores
Jackson, Meyer B.
2009-01-01
Membranes fuse by forming highly curved intermediates, culminating in structures described as fusion pores. These hourglass-like figures that join two fusing membranes have high bending energies, which can be estimated using continuum elasticity models. Fusion pore bending energies depend strongly on shape, and the present study developed a method for determining the shape that minimizes bending energy. This was first applied to a fusion pore modeled as a single surface and then extended to a...
Fuzzy analysis of serviceability limit state of slender steel beam under bending
Energy Technology Data Exchange (ETDEWEB)
Kala, Zdeněk; Valeš, Jan [Brno University of Technology, Faculty of Civil Engineering, Department of Structural Mechanics Vevefi St. 95, ZIP 602 00, Brno (Czech Republic)
2015-03-10
In the present paper, deformations of a beam under equal end moments solved with influence of lateral buckling are studied. It has been found by numerical studies that the lateral deflection of slender beam under major axis bending can be relatively high.The acceptability of high values of lateral deflections within the framework of serviceability limit state is discussed. In the next part of the paper, the limit value of maximum deflection was introduced as a fuzzy number. The fuzzy analysis of the maximum moment which causes the maximum deflection was carried out. The slendernesses of beams for which the serviceability limit state is the limiting state for design were identified.
Energy Technology Data Exchange (ETDEWEB)
Batista, Gilmar Zacca; Sanandres, Simon Ricardo [PETROBRAS, Rio de Janeiro, RJ (Brazil). Pipeline Engineering Division; Pinto, Percy Saavedra; Mello, Marcelo [Tubos Soldados Atlantico, Sao Paulo, SP (Brazil)
2009-07-01
The present work is a part of a comprehensive program that aims to evaluate the helical seam pipe application in pipeline construction and compare with the traditional longitudinal seam pipe that have been used in Brazil. One of the biggest concerns is the cold bending process once the Brazilian land profile is very sinuous, different than other countries where helical seam pipes have been used successfully. At this work, two pipes were used, one helical seam and one longitudinal seam, both API 5L X70 with 28 inch of diameter and 0.469 inch wall thickness. The results of cold bending tests comparing both types of pipe and the mechanical properties from the straight pipe with the bend section are shown. The research methodology includes dimensional analysis, microstructural evaluation and mechanical tests that were performed on the straight pipe and bend areas. The cold bending parameters used to obtain a bend according the design and construction standards requirements are also presented. The results showed that the cold bending process produces a helical seam pipe bend with the most critical radius allowed by the standards, without presenting any evidence of wrinkles, out-of-roundness above the limits or any type of mechanical damage. Both pipes tested met the standards requirements in terms of bending and mechanical properties. The results of this study provide technical information for future helical seam pipe application in Brazil. (author)
Stoimenov, Boyko L.; Rossiter, Jonathan M.; Mukai, Toshiharu
2007-01-01
Demands from the fields of bio-medical engineering and biologically-inspired robotics motivate a growing interest in actuators with properties similar to biological muscle, including ionic polymer-metal composites (IPMC), the focus of this study. IPMC actuators consist of an ion-conductive polymer membrane, coated with thin metal electrodes on both sides and bend when voltage is applied. Some of the advantages of IPMC actuators are their softness, lack of moving parts, easy miniaturization, light weight and low actuation voltage. When used in bio-mimetic robotic applications, such as a snake-like swimming robot, locomotion speed can be improved by increasing the bending amplitude. However, it cannot be improved much by increasing the driving voltage, because of water electrolysis. To enhance the bending response of IPMCs we created a "preferred" bending direction by anisotropic surface modification. Introduction of anisotropic roughness with grooves across the length of the actuator improved the bending response by a factor of 2.1. Artificially introduced cracks on the electrodes in direction, in which natural cracks form by bending, improved bending response by a factor of 1.6. Anisotropic surface modification is an effective method to enhance the bending response of IPMC actuators and does not compromise their rigidity under loads perpendicular to the bending plane.
Bouzid, T.; Demagh, K.
2011-03-01
Reinforced and concrete-encased composite columns of arbitrarily shaped cross sections subjected to biaxial bending and axial loads are commonly used in many structures. For this purpose, an iterative numerical procedure for the strength analysis and design of short and slender reinforced concrete columns with a square cross section under biaxial bending and an axial load by using an EC2 stress-strain model is presented in this paper. The computational procedure takes into account the nonlinear behavior of the materials (i.e., concrete and reinforcing bars) and includes the second - order effects due to the additional eccentricity of the applied axial load by the Moment Magnification Method. The ability of the proposed method and its formulation has been tested by comparing its results with the experimental ones reported by some authors. This comparison has shown that a good degree of agreement and accuracy between the experimental and theoretical results have been obtained. An average ratio (proposed to test) of 1.06 with a deviation of 9% is achieved.
Institute of Scientific and Technical Information of China (English)
XU ShiLang; LI QingHua
2009-01-01
Ultrahigh toughness cementitious composites (UHTCC) obviously show strain hardening property under tensile or bending loading. The failure pattern of the UHTCC components exhibits multiple fine cracks under uniaxial tensile loading with prominent tensile strain capacity in excess of 3%, with merely 60 μm average crack width even corresponding to the ultimate tensile strain state. The approach adopted is based on the concept of functionally-graded concrete, where part of the concrete, which surrounds the main longitudinal reinforcement in a RC (reinforced concrete) member, is strategically replaced with UHTCC with excellent crack-controlling ability. Investigations on bending behavior of functionally-graded composite beam crack controlled by UHTCC has been carried out, including theo-retical analysis, experimental research on long composite beams without web reinforcement, validation and comparison between experimental and theoretical results, and analysis on crack control. In addi-tion to improving bearing capacity, the results indicate that functionally-graded composite beams using UHTCC has been found to be very effective in preventing corrosion-induced damage compared with RC beams. Therefore, durability and service life of the structure could be enhanced. This paper discusses the development of internal force and crack propagation during loading process, and presents analysis of the internal force in different stages, moment-curvature relationship from loading to damage and calculation of mid-span deflection and ductility index. In the end, the theoretical formulae have been validated by experimental results.
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
Ultrahigh toughness cementitious composites (UHTCC) obviously show strain hardening property under tensile or bending loading. The failure pattern of the UHTCC components exhibits multiple fine cracks under uniaxial tensile loading with prominent tensile strain capacity in excess of 3%, with merely 60 μm average crack width even corresponding to the ultimate tensile strain state. The approach adopted is based on the concept of functionally-graded concrete, where part of the concrete, which surrounds the main longitudinal reinforcement in a RC (reinforced concrete) member, is strategically replaced with UHTCC with excellent crack-controlling ability. Investigations on bending behavior of functionally-graded composite beam crack controlled by UHTCC has been carried out, including theo- retical analysis, experimental research on long composite beams without web reinforcement, validation and comparison between experimental and theoretical results, and analysis on crack control. In addition to improving bearing capacity, the results indicate that functionally-graded composite beams using UHTCC has been found to be very effective in preventing corrosion-induced damage compared with RC beams. Therefore, durability and service life of the structure could be enhanced. This paper discusses the development of internal force and crack propagation during loading process, and presents analysis of the internal force in different stages, moment-curvature relationship from loading to damage and calculation of mid-span deflection and ductility index. In the end, the theoretical formulae have been validated by experimental results.
Peeling, sliding, pulling and bending
Lister, John; Peng, Gunnar
2015-11-01
The peeling of an elastic sheet away from thin layer of viscous fluid is a simply-stated and generic problem, that involves complex interactions between the flow and elastic deformation on a range of length scales. Consider an analogue of capillary spreading, where a blister of injected viscous fluid spreads due to tension in the overlying elastic sheet. Here the tension is coupled to the deformation of the sheet, and thus varies in time and space. A key question is whether or not viscous shear stresses ahead of the blister are sufficient to prevent the sheet sliding inwards and relieving the tension. Our asymptotic analysis reveals a dichotomy between fast and slow spreading, and between two-dimensional and axisymmetric spreading. In combination with bending stresses and gravity, which may dominate parts of the flow but not others, there is a plethora of dynamical regimes.
Differentiability of quantum moment maps
Hamachi, Kentaro
2002-01-01
We study quantum moment maps of $G$-invariant star products, which are a quantum analogue of the moment map for classical Hamiltonian systems. Introducing an integral representation, we show that any quantum moment map for a $G$-invariant star product is differentiable. This property gives us a new method for the classification of $G$-invariant star products on regular coadjoint orbits of compact semisimple Lie groups.
The moments of strength functions
International Nuclear Information System (INIS)
In this paper we show that a moment of order n of the strength function is determined by the same order of the Brillouin-Wigner perturbative expansion. This fact is used to study the second moment for single-particle and collective excitations in the framework of nuclear field theory. We discuss the relationship of the second moment with the spreading width of the giant isovector M1 resonances in 208Pb. (orig.)
Quasi-static and dynamical bending of a cantilever poroelastic beam
Institute of Scientific and Technical Information of China (English)
YANG Yi; LI Li; YANG Xiao
2009-01-01
Based on the theory of porous media, the quasi-static and dynamical bending of a cantilever poroelastic beam subjected to a step load at its free end is investigated, and the influences of its permeability on bending deformation is examined.The initial boundary value problems for dynamical and quasi-static responses are solved with the Laplace transform technique,and the deflections, the bending moments of the solid skeleton and the equivalent couples of the pore fluid pressure are shown in figures. It is shown that the dynamical and quasi-static behavior of the saturated poroelastic beam depends closely on the permeability conditions at the beam ends. Under the different permeability conditions, the deflections of the beam may oscillate or not. The Mandel-Cryer effect also exists in liquid-saturated poroelastic beams.
International Nuclear Information System (INIS)
The induction heating bending process, which has been recently applied to nuclear piping, can generate residual stresses due to thermomechanical mechanism during the process. This residual stress is one of the crack driving forces that have important effects on crack initiation and propagation. However, previous studies have focused only on geometric shape variations such as the change in thickness and ovality. Moreover, very few studies are available on the effects of process variables on residual stresses. This study investigated the effects of process variables on the residual stress distributions of induction heating bended austenitic stainless steel (316 series) piping using parametric finite element analysis. The results indicated that the heat generation rate and feed velocity have significant effects on the residual stresses whereas the moment and bending angle have insignificant effects
Energy Technology Data Exchange (ETDEWEB)
Motz, C. [IZBS, University of Karlsruhe - TH, Kaiserstrasse 12, 76131 Karlsruhe (Germany); Erich Schmid Institute, Austrian Academy of Sciences, Jahnstrasse 12, 8700 Leoben (Austria)], E-mail: motz@unileoben.ac.at; Weygand, D.; Senger, J.; Gumbsch, P. [IZBS, University of Karlsruhe - TH, Kaiserstrasse 12, 76131 Karlsruhe (Germany)
2008-05-15
Discrete dislocation dynamics simulations in three dimensions are performed on micro-sized bending beams and the results are compared with experiments. A strong size dependence of the flow stress {sigma}{sub f} (or bending moment) is found. The flow stress scales approximately inversely with the beam thickness t. The simulations show that the dislocation structure exhibits pronounced pile-ups around the neutral plane of the beam. The back stress from these pile-ups on the dislocation sources is analyzed by means of an analytical pile-up model. It is shown that the scaling behavior {sigma}{sub f}{proportional_to}t{sup -1} can be explained by a combination of pile-up and source size limitation. Subsequently, the applicability of strain gradient plasticity models on micro-bending is discussed.
Closed forms and multi-moment maps
Madsen, Thomas Bruun
2011-01-01
We extend the notion of multi-moment map to geometries defined by closed forms of arbitrary degree. We give fundamental existence and uniqueness results and discuss a number of essential examples, including geometries related to special holonomy. For forms of degree four, multi-moment maps are guaranteed to exist and are unique when the symmetry group is (3,4)-trivial, meaning that the group is connected and the third and fourth Lie algebra Betti numbers vanish. We give a structural description of some classes of (3,4)-trivial algebras and provide a number of examples.
The Method of Moments in electromagnetics
Gibson, Walton C
2014-01-01
Now Covers Dielectric Materials in Practical Electromagnetic DevicesThe Method of Moments in Electromagnetics, Second Edition explains the solution of electromagnetic integral equations via the method of moments (MOM). While the first edition exclusively focused on integral equations for conducting problems, this edition extends the integral equation framework to treat objects having conducting as well as dielectric parts.New to the Second EditionExpanded treatment of coupled surface integral equations for conducting and composite conducting/dielectric objects, including objects having multipl
Status and perspectives of neutrino magnetic moments
Studenikin, Alexander
2016-01-01
Basic theoretical and experimental aspects of neutrino magnetic moments are reviewed, including the present best upper bounds from reactor experiments and astrophysics. An interesting effect of neutrino spin precession and oscillations induced by the background matter transversal current or polarization is also discussed.
Asymptotic theory of integrated conditional moment tests
Bierens, H.J.; Ploberger, W.
1995-01-01
In this paper we derive the asymptotic distribution of the test statistic of a generalized version of the integrated conditional moment (ICM) test of Bierens (1982, 1984), under a class of Vn-local alternatives, where n is the sample size. The generalized version involved includes neural network tes
International Nuclear Information System (INIS)
Lower bound limit load solutions for surface cracks in plates under combined end force, cross-thickness bending moment and tensile/compressive membrane stress parallel to the crack are derived based on the von Mises yield criterion. From these solutions, particular limit loads for plates with extended surface cracks and through-thickness cracks or uncracked plates under the same loading conditions are obtained. The limit load solutions for surface cracks in plates under combined tension and bending due to Lei and Fox can be reproduced from the solutions in this paper by setting the stress parallel to the crack plane to zero. - Highlights: • Lower bound global limit load solution for rectangular surface cracks in plates. • Combined biaxial stress/force and cross-thickness bending moment. • Solutions based on lower bound limit load theorem and von Mises yield criterion. • Solutions valid for proportional/non-proportional loading
Future Muon Dipole Moment Measurements
Roberts, B. Lee
2004-01-01
From the famous experiments of Stern and Gerlach to the present, measurements of magnetic dipole moments, and searches for electric dipole moments of ``elementary'' particles have played a major role in our understanding of sub-atomic physics. In this talk I discuss the progress on measurements and theory of the magnetic dipole moment of the muon. I also discuss a new proposal to search for a permanent electric dipole moment (EDM) of the muon and put it into the more general context of other ...
International Nuclear Information System (INIS)
The possibility of using ultrasonic testing for fracture toughness of 15Kh3NMFA steel specimens is shown. The technique and equipment for three-point bending correspond to the requirements for crack propagation testing. The moment of fracture initiation has been determined through the bending point on the ΔH -P diagram, where Δ/H is a stress change proportional to the echo - signal and P is a load. The I-integral value deviations do not exceed 4%
Experiment and prediction in the bending of a nickel beam at 200/sup 0/C
Energy Technology Data Exchange (ETDEWEB)
Mautz, J.A.; Hart, E.W.
1979-05-01
The results of an experiment on the bending response of a Nickel prismatic beam under four point loading at 200/sup 0/C are described. The specimens have been subjected to histories of steady applied moment with a sequence of step changes both positive and negative. The measured results are compared with predictions based on Hart's constitutive equations. The experimental conditions and procedures are described. The experiment and the predictions are compared with prior studies.
Kamiński, M.; Supeł, Ł.
2016-02-01
It is widely known that lateral-torsional buckling of a member under bending and warping restraints of its cross-sections in the steel structures are crucial for estimation of their safety and durability. Although engineering codes for steel and aluminum structures support the designer with the additional analytical expressions depending even on the boundary conditions and internal forces diagrams, one may apply alternatively the traditional Finite Element or Finite Difference Methods (FEM, FDM) to determine the so-called critical moment representing this phenomenon. The principal purpose of this work is to compare three different ways of determination of critical moment, also in the context of structural sensitivity analysis with respect to the structural element length. Sensitivity gradients are determined by the use of both analytical and the central finite difference scheme here and contrasted also for analytical, FEM as well as FDM approaches. Computational study is provided for the entire family of the steel I- and H - beams available for the practitioners in this area, and is a basis for further stochastic reliability analysis as well as durability prediction including possible corrosion progress.
Directory of Open Access Journals (Sweden)
Kamiński M.
2016-02-01
Full Text Available It is widely known that lateral-torsional buckling of a member under bending and warping restraints of its cross-sections in the steel structures are crucial for estimation of their safety and durability. Although engineering codes for steel and aluminum structures support the designer with the additional analytical expressions depending even on the boundary conditions and internal forces diagrams, one may apply alternatively the traditional Finite Element or Finite Difference Methods (FEM, FDM to determine the so-called critical moment representing this phenomenon. The principal purpose of this work is to compare three different ways of determination of critical moment, also in the context of structural sensitivity analysis with respect to the structural element length. Sensitivity gradients are determined by the use of both analytical and the central finite difference scheme here and contrasted also for analytical, FEM as well as FDM approaches. Computational study is provided for the entire family of the steel I- and H - beams available for the practitioners in this area, and is a basis for further stochastic reliability analysis as well as durability prediction including possible corrosion progress.
Effect of couple-stress on the pure bending of a prismatic bar
International Nuclear Information System (INIS)
An evaluation of the applicability of the couple-stress theory to the stress analysis of graphite structures is performed by solving a pure bending problem. The differences between solutions from the couple-stress theory and from the classical theory of elasticity are compared. It is found that the differences are sufficient to account for the inconsistencies which have often been observed between the classical elasticity theory and actual behavior of graphite under bend and tensile loadings. An experimental procedure to measure the material constants in the couple-stress theory is also suggested. The linear couple-stress theory, the origins of which go back to the turn of the last century, adds linear relations between couple-stresses and rotation gradients to the classical stress-strain law. By adopting the classical assumption that the plane cross section remains plane after deformation, the pure-bending problem is reduced to a plane couple-stress problem with traction-free boundary conditions. A general solution for an isotropic elastic prismatic bar under pure bending is then obtained using the Airy stress function and another stress function wich accounts for the couple-stresss. For a cylindrical bar, it reduces to a simple series solution. The moment-curvature and stress-curvature relations derived for a cylindrical bar from the general solution are used to examine the effect of couple-stresses. Numerical compilation of relations indicates that the couple stress parameters can be practically determined by measuring the moment-curvature ratio of various diametered specimens under bending. Although there is not sufficient data for such evaluation at present, it appears that the theory is consistent with the limited bend and tensile strength data of cylindrical specimens for H-451 graphite
Thermally-induced bending-torsion coupling vibration of large scale space structures
Xue, Ming-De; Duan, Jin; Xiang, Zhi-Hai
2007-09-01
In this paper, a finite element scheme is developed to solve the problem of thermally-induced bending-torsion coupling vibration of large scale space structures, which are usually composed of thin-walled beams with open and closed cross-section. A two-noded finite element is proposed to analyze the transient temperature field over the longitudinal and circumferential direction of a beam. Since this temperature element can share the same mesh with the two-noded beam element of Euler-Bernoulli type, a unified finite element scheme is easily formulated to solve the thermal-structural coupling problem. This scheme is characterized with very strong nonlinear formulation, due to the consideration of the thermal radiation and the coupling effect between structural deformations and the incident normal heat flux. Moreover, because the warping is taken into account, not only the thermal axial force and thermal bending moments but also the thermal bi-moment are presented in the formulation. Consequently, the thermally-induced bending-torsion coupling vibration can be simulated. The performance of the proposed computational scheme is illustrated by the analysis of the well-known failure of Hubble space telescope solar arrays. The results reveal that the thermally-induced bending-torsion coupling vibration is obviously presented in that case and could be regarded as a cause of failure.
Bandwidth engineering of photonic crystal waveguide bends
DEFF Research Database (Denmark)
Borel, Peter Ingo; Frandsen, Lars Hagedorn; Harpøth, Anders;
2004-01-01
An effective design principle has been applied to photonic crystal waveguide bends fabricated in silicon-on-insulator material using deep UV lithography resulting in a large increase in the low-loss bandwidth of the bends. Furthermore, it is experimentally demonstrated that the absolute bandwidth...
2010-10-01
....1 of ASME B31.1 (incorporated by reference; see 46 CFR 56.01-2). This shall not prohibit the use of..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PIPING SYSTEMS AND APPURTENANCES Bending and Forming § 56.80-5 Bending. Pipe may be bent by any hot or cold method and to any radius which will...
Bends and splitters in graphene nanoribbon waveguides
DEFF Research Database (Denmark)
Zhu, Xiaolong; Yan, Wei; Mortensen, N. Asger;
2013-01-01
We investigate the performance of bends and splitters in graphene nanoribbon waveguides. Although the graphene waveguides are lossy themselves, we show that bends and splitters do not induce any additional loss provided that the nanoribbon width is sub-wavelength. We use transmission line theory...
Photoacoustic elastic bending in thin film—Substrate system
International Nuclear Information System (INIS)
Theoretical model for optically excited two-layer elastic plate, which includes plasmaelastic, thermoelastic, and thermodiffusion mechanisms, is given in order to study the dependence of the photoacoustic (PA) elastic bending signal on the optical, thermal, and elastic properties of thin film—substrate system. Thin film-semiconductor sample (in our case Silicon) is modeled by simultaneous analysis of the plasma, thermal, and elastic wave equations. Multireflection effects in thin film are included in theoretical model and analyzed. Relations for the amplitude and phase of electronic and thermal elastic bending in the optically excited two-layer mechanically-supported circular plate are derived. Theoretical analysis of the thermodiffusion, plasmaelastic, and thermoelastic effects in a sample-gas-microphone photoacoustic detection configuration is given. Two normalization procedures of the photoacoustic elastic bending signal in function of the modulation frequency of the optical excitation are established. Given theoretical model can be used for various photoacoustic detection configurations, for example, in the study of optical, thermal, and elastic properties of the dielectric-semiconductor or metal-semiconductor structure, etc., Theoretical analysis shows that it is possible to develop new noncontact and nondestructive experimental method—PA elastic bending method for thin film study, with possibility to obtain the optical, thermal, and elastic parameters of the film thinner than 1 μm
Local Deplanation Of Double Reinforced Beam Cross Section Under Bending
Baltov, Anguel; Yanakieva, Ana
2015-12-01
Bending of beams, double reinforced by means of thin composite layers, is considered in the study. Approximate numerical solution is proposed, considering transitional boundary areas, where smooth quadratic transition of the elasticity modulus and deformations take place. Deplanation of the cross section is also accounted for in the areas. Their thickness is found equalizing the total stiffness of the cross section and the layer stiffness. Deplanation of the cross section of the transitional area is determined via the longitudinal deformation in the reinforcing layer, accounting for the equilibrium between the internal and the external moment, generated by the longitudinal stresses in the cross section. A numerical example is given as an illustration demonstrating model's plausibility. The model allows the design and the calculation of recycled concrete beams double reinforced by means of thin layers. The approach is in agreement with modern design of nearly zero energy buildings (NZEB).
Local Deplanation Of Double Reinforced Beam Cross Section Under Bending*
Directory of Open Access Journals (Sweden)
Baltov Anguel
2015-12-01
Full Text Available Bending of beams, double reinforced by means of thin composite layers, is considered in the study. Approximate numerical solution is proposed, considering transitional boundary areas, where smooth quadratic transition of the elasticity modulus and deformations take place. Deplanation of the cross section is also accounted for in the areas. Their thickness is found equalizing the total stiffness of the cross section and the layer stiffness. Deplanation of the cross section of the transitional area is determined via the longitudinal deformation in the reinforcing layer, accounting for the equilibrium between the internal and the external moment, generated by the longitudinal stresses in the cross section. A numerical example is given as an illustration demonstrating model’s plausibility. The model allows the design and the calculation of recycled concrete beams double reinforced by means of thin layers. The approach is in agreement with modern design of nearly zero energy buildings (NZEB.
Bending of light in conformal Weyl gravity
Sultana, Joseph; Kazanas, Demosthenes
2010-06-01
We reexamine the bending of light issue associated with the metric of the static, spherically symmetric solution of Weyl gravity discovered by Mannheim and Kazanas (1989). To this end we employ the procedure used recently by Rindler and Ishak to obtain the bending angle of light by a centrally concentrated spherically symmetric matter distribution in a Schwarzschild-de Sitter background. In earlier studies the term γr in the metric led to the paradoxical result of a bending angle proportional to the photon impact parameter, when using the usual formalism appropriate to asymptotically flat space-times. However, employing the approach of light bending of Rindler and Ishak we show that the effects of this term are in fact insignificant, with the discrepancy between the two procedures attributed to the definition of the bending angle between the asymptotically flat and nonflat spaces.
49 CFR 195.212 - Bending of pipe.
2010-10-01
... 49 Transportation 3 2010-10-01 2010-10-01 false Bending of pipe. 195.212 Section 195.212... PIPELINE Construction § 195.212 Bending of pipe. (a) Pipe must not have a wrinkle bend. (b) Each field bend must comply with the following: (1) A bend must not impair the serviceability of the pipe. (2)...
49 CFR 192.313 - Bends and elbows.
2010-10-01
... 49 Transportation 3 2010-10-01 2010-10-01 false Bends and elbows. 192.313 Section 192.313... Lines and Mains § 192.313 Bends and elbows. (a) Each field bend in steel pipe, other than a wrinkle bend... tested either before or after the bending process. (c) Wrought-steel welding elbows and...
2002-01-01
Experiment IS358 uses the intense and pure beams of copper isotopes provided by the ISOLDE RILIS (resonance ionization laser ion source). The isotopes are implanted and oriented in the low temperature nuclear orientation set-up NICOLE. Magnetic moments are measured by $\\beta$-NMR. Copper (Z=29), with a single proton above the proton-magic nickel isotopes provides an ideal testground for precise shell model calculations of magnetic moments and their experimental verification. In the course of our experiments we already determined the magnetic moments of $^{67}$Ni, $^{67}$Cu, $^{68g}$Cu, $^{69}$Cu and $^{71}$Cu which provide important information on the magicity of the N=40 subshell closure. In 2001 we plan to conclude our systematic investigations by measuring the magnetic moment of the neutron-deficient isotope $^{59}$Cu. This will pave the way for a subsequent study of the magnetic moment of $^{57}$Cu with a complementary method.
Moment Distributions of Phase Type
DEFF Research Database (Denmark)
Bladt, Mogens; Nielsen, Bo Friis
In this paper we prove that the class of distributions on the positive reals with a rational Laplace transform, also known as matrix-exponential distributions, is closed under formation of moment distributions. In particular, the results are hence valid for the well known class of phase-type dist......In this paper we prove that the class of distributions on the positive reals with a rational Laplace transform, also known as matrix-exponential distributions, is closed under formation of moment distributions. In particular, the results are hence valid for the well known class of phase......-type distributions. We construct representations for moment distributions based on a general matrix-exponential distribution which turns out to be a generalization of the moment distributions based on exponential distributions. For moment distributions based on phase{type distributions we find an appropriate...
Why and how to normalize the factorial moments of intermittency
International Nuclear Information System (INIS)
The normalization of factorial moments of intermittency, which is often the subject of controverses, is justified and (re-)derived from the general assumption of multi-Poissonian statistical noise in the production of particles at high-energy. Correction factors for the horizontal vs. Vertical analyses are derived in general cases, including the factorial multi-bin correlation moments
Employment of concentrated-hardsphere- suspension pad for V-bending of thin strip
Directory of Open Access Journals (Sweden)
T. Ohashi
2008-12-01
Full Text Available Purpose: Authors have suggested employment of dilatant fluid for metal forming tools, and report an applicationon v-bending of thin stainless steel strips in this paper.Design/methodology/approach: An alumina concentrated hard-sphere suspension is employed as dilatant fluid forforming. The authors evaluate the suspension with backward extrusion test. Then, the authors try to bend SUS304stainless strip with 0.25 mm thickness and 30 mm width on the pad of the suspension with a v-bend punch.Findings: Behaviour of the suspension is revealed in backward extrusion test. Migration of water takesimportant role in it. In v-bending test, including acute angle bending, the authors bend the strip with only thev-bend punch and the alumina concentrated hard-sphere suspension pad successfully. It is thought that formingload is less than with general polyurethane tools.Research limitations/implications: Spring-back in partial bending, which is similar to the suggested process,is larger than in bottoming and coining with dies and bending with polyurethane tools. Therefore, the authorsare going to evaluate the spring-back in the suggested process in further study.Practical implications: Polyurethane pad is used in bending process generally because of advantageous pointsin easy-design, and safe from scratch. However it has disadvantageous points in its limited life and necessity oflarge forming load. The alumina concentrated hard-sphere suspension can be employed for such the pad withunlimited life. In addition, such the dilatant fluid can be applied on other metal forming process as easy tool.Originality/value: Employing dilatant fluid for forming tools is new idea. Authors try v-bending with analumina concentrated hard-sphere suspension.
International Nuclear Information System (INIS)
The determination of critical crack sizes or permissible/allowable loading levels in pipes with degraded pipe sections (circumferential cracks) for the assurance of component integrity is usually based on deterministic approaches. Therefore along with numerical calculational methods (finite element (FE) analyses) limit load calculations, such as e.g. the 'Plastic limit load concept' and the 'Flow stress concept' as well as fracture mechanics approximation methods as e.g. the R-curve method or the 'Ductile fracture handbook' and the R6-Method are currently used for practical application. Numerous experimental tests on both ferritic and austenitic pipes with different pipe dimensions were investigated at MPA Stuttgart. The geometries of the pipes were comparable to actual piping systems in Nuclear Power Plants, both BWR as well as PWR. Through wall cracks and part wall through cracks on the inside surface of the pipes were considered. The results of these tests were used to determine the flow stresses used within the limit load calculations. Therefore the deterministic concepts assessing the integrity of degraded pipes are available A new post-calculation of the above mentioned tests was performed using probabilistic approaches to assure the component integrity of degraded piping systems. As a result the calculated probability of failure was compared to experimental behaviour during the pipe test. Different reliability techniques were used for the verification of the probabilistic approaches. (author)
Wing flapping with minimum energy. [minimize the drag for a bending moment at the wing root
Jones, R. T.
1980-01-01
For slow flapping motions it is found that the minimum energy loss occurs when the vortex wake moves as a rigid surface that rotates about the wing root - a condition analogous to that determined for a slow-turning propeller. The optimum circulation distribution determined by this condition differs from the elliptic distribution, showing a greater concentration of lift toward the tips. It appears that very high propulsive efficiencies are obtained by flapping.
Stochastic Procedures for Extreme Wave Load Predictions- Wave Bending Moment in Ships
DEFF Research Database (Denmark)
Jensen, Jørgen Juncher
2009-01-01
A discussion of useful stochastic procedures for stochastic wave load problems is given, covering the range from slightly linear to strongly non-linear (bifurcation) problems. The methods are: Hermite transformation, Critical wave episodes and the First Order Reliability Method (FORM). The proced...
Bending strength model for internal spur gear teeth
Savage, Michael; Rubadeux, K. L.; Coe, H. H.
1995-01-01
Internal spur gear teeth are normally stronger than pinion teeth of the same pitch and face width since external teeth are smaller at the base. However, ring gears which are narrower have an unequal addendum or are made of a material with a lower strength than that of the meshing pinion may be loaded more critically in bending. In this study, a model for the bending strength of an internal gear tooth as a function of the applied load pressure angle is presented which is based on the inscribed Lewis constant strength parabolic beam. The bending model includes a stress concentration factor and an axial compression term which are extensions of the model for an external gear tooth. The geometry of the Lewis factor determination is presented, the iteration to determine the factor is described, and the bending strength J factor is compared to that of an external gear tooth. This strength model will assist optimal design efforts for unequal addendum gears and gears of mixed materials.
Social support modifies association between forward bending of the trunk and low-back pain
DEFF Research Database (Denmark)
Villumsen, Morten; Holtermann, Andreas; Samani, Afshin;
2016-01-01
-reported social support was categorized into low, moderate, and high levels. Multi-adjusted logistic regressions estimated the association between forward bending and LBPi and the effect modification by social support. RESULTS: Forward bending and LBPi were not significantly associated but modified by social......OBJECTIVES: This study aimed to investigate the association between forward bending of the trunk and low-back pain intensity (LBPi) among blue-collar workers in Denmark as well as whether the level of social support modifies the association. METHODS: In total, 457 workers were included in the study...... support. Workers with low social support and long duration of forward bending had higher likelihood of high LBPi [odds ratio (OR) 2.97, 95% confidence interval (95% CI) 1.11-7.95] compared to workers with high social support and long duration of forward bending. Among workers with low social support...
Aristizabal-Ochoa, Jose Dario
2012-01-01
An analytical method and the closed-form expressions derived in a companion paper are used to evaluate the induced elastic bending moments and second-order deflections in slender prismatic columns with initial geometric imperfections (i.e., initial curvature and out-of-plumbness) and semirigid connections when the columns are subjected to eccentric axial loads at both ends. Comparisons of the induced elastic moments, the second-order deflections, and the critical loads obtained using the prop...
Measurement of irradiation creep in bending
International Nuclear Information System (INIS)
The major deformation modes in LMFBR fuel channels are bowing caused by neutron flux and temperature gradients and dilation due to stresses imposed by the flowing sodium. In both cases, the stress state of interest is bending. The bulk of irradiation creep data has been generated by simply loaded specimens such as tensile or biaxial pressurized tubes but it is questionable whether this data can be used to predict creep in bending. An irradiation creep experiment using beams loaded in primary bending has been designed to investigate this premise
Measurement of irradiation creep in bending. [LMFBR
Energy Technology Data Exchange (ETDEWEB)
McSherry, A.J.; Marshall, J.; Patel, M.R.
1980-01-31
The major deformation modes in LMFBR fuel channels are bowing caused by neutron flux and temperature gradients and dilation due to stresses imposed by the flowing sodium. In both cases, the stress state of interest is bending. The bulk of irradiation creep data has been generated by simply loaded specimens such as tensile or biaxial pressurized tubes but it is questionable whether this data can be used to predict creep in bending. An irradiation creep experiment using beams loaded in primary bending has been designed to investigate this premise.
Three Moments in Jewish Philosophy
Directory of Open Access Journals (Sweden)
Stefan Goltzberg
2012-04-01
Full Text Available I would like to thank the following people for having proofread my text: Noémie Benchimol, Shemuel Lampronti and Georges-Elia Sarfati. The purpose of this article is to offer a new periodization of Jewish philosophy and to reflect on the definition of Jewish philosophy. It will therefore deal with the characteristic style of each Jewish philosophy rather than with their content. I shall identify three moments in the history of Jewish philosophy: the Arab moment, the German moment, and the an...
Hyperon polarization and magnetic moments
International Nuclear Information System (INIS)
Inclusively produced hyperons with significant polarization were first observed at Fermilab about seventeen years ago. This and subsequent experiments showed that Λ degree were produced polarized while bar Λ degree had no polarization in the same kinematical region. This set the stage for many experiments which showed that most hyperons are produced polarized. Recent Fermilab experiments have showed that this phenomena is even more complex and theoretical understanding is still lacking. Nevertheless polarized hyperon beams have been an extremely useful experimental tool in measuring hyperon magnetic moments. Recently, magnetic moment precession of channeled particles in bent crystals has been observed. This opens the possibility of measuring the magnetic moments of charmed baryons
Numerical Evaluation of Bending Load Effect on the Failure Pressure of Wall-Thinned Pipe Bends
International Nuclear Information System (INIS)
During the normal operating conditions, piping systems in nuclear power plants (NPPs) are subject not only to internal pressure but also to bending loads induced by deadweight, thermal expansion, and internal pressure. Bending is thus considered to be an important factor in evaluating the integrity of piping components in NPPs. Local wall-thinning due to flow accelerated corrosion is a main degradation mechanism of carbon steel piping components in NPPs, and the integrity evaluation of wall-thinned piping components has become an important issue. This study investigated the effects of bending load on the failure of wall-thinned pipe bends under internal pressure. Our previous study experimentally evaluated the bending load effects on the failure pressure of wall-thinned elbows under displacement controlled in-plane bending load, but the numbers of experimental data were insufficient to determine the effects of bending load on the failure pressure of wall-thinned pipe bends. Therefore, the present study systematically evaluates the effects of bending load on the failure pressure of wall-thinned pipe bends using parametric finite element analyses
Face recognition using Krawtchouk moment
Indian Academy of Sciences (India)
J Sheeba Rani; D Devaraj
2012-08-01
Feature extraction is one of the important tasks in face recognition. Moments are widely used feature extractor due to their superior discriminatory power and geometrical invariance. Moments generally capture the global features of the image. This paper proposes Krawtchouk moment for feature extraction in face recognition system, which has the ability to extract local features from any region of interest. Krawtchouk moment is used to extract both local features and global features of the face. The extracted features are fused using summed normalized distance strategy. Nearest neighbour classiﬁer is employed to classify the faces. The proposed method is tested using ORL and Yale databases. Experimental results show that the proposed method is able to recognize images correctly, even if the images are corrupted with noise and possess change in facial expression and tilt.
Radiation reaction of multipole moments
International Nuclear Information System (INIS)
A Poincare-invariant description is proposed for the effective dynamics of a localized system of charged particles in classical electrodynamics in terms of the intrinsic multipole moments of the system. A relativistic-invariant definition for the intrinsic multipole moments of a system of charged particles is given. A new generally covariant action functional for a relativistic perfect fluid is proposed. In the case of relativistic charged dust, it is proven that the description of the problem of radiation reaction of multipole moments by the model of particles is equivalent to the description of this problem by a hydrodynamic model. An effective model is obtained for a pointlike neutral system of charged particles that possesses an intrinsic dipole moment, and the free dynamics of this system is described. The bound momentum of a point dipole is found
Radiation reaction of multipole moments
Kazinski, P. O.
2007-08-01
A Poincaré-invariant description is proposed for the effective dynamics of a localized system of charged particles in classical electrodynamics in terms of the intrinsic multipole moments of the system. A relativistic-invariant definition for the intrinsic multipole moments of a system of charged particles is given. A new generally covariant action functional for a relativistic perfect fluid is proposed. In the case of relativistic charged dust, it is proven that the description of the problem of radiation reaction of multipole moments by the model of particles is equivalent to the description of this problem by a hydrodynamic model. An effective model is obtained for a pointlike neutral system of charged particles that possesses an intrinsic dipole moment, and the free dynamics of this system is described. The bound momentum of a point dipole is found.
Moment Invariants for Object Recognition
Czech Academy of Sciences Publication Activity Database
Flusser, Jan
Boca Raton: Wiley&Sons, 2015. ISBN 9780471346081 Institutional support: RVO:67985556 Keywords : invariants * object recognition * moments Subject RIV: JC - Computer Hardware ; Software http://library.utia.cas.cz/separaty/2015/ZOI/flusser-0442976.pdf
A flexible sensor measuring displacement and bending
Nishijima, Takashi; Yamamoto, Akio; Higuchi, Toshiro
2009-04-01
This paper proposes a new sensor that is capable of measuring both linear displacement and bending. The sensor is designed to be used with an electrostatic film motor that features mechanical flexibility, but can also be used as an independent sensor. The sensor employs three-phase electrodes both in sliding and stationary parts and estimates displacement and bending from the change of the capacitance between the electrodes. The paper describes an equivalent capacitance-network model for the sensor. Based on the model, sensing principles for both displacement and bending are presented and analyzed. The analyses are experimentally verified using a prototype sensor. The experimental results show that the prototype sensor could measure both displacement and bending with little interference between them.
On Regression Standardization for Moments
CLIFFORD C. CLOGG; SCOTT R. ELIASON
1986-01-01
Polynomial regression models can be used to standardize means of endogenous variables for moments of exogenous variables. In other words, standardized means obtained from polynomial models adjust for group differences in location and shape parameters that characterize distributions of exogenous variables. The suggested approach is a natural extension of the conventional method of regression standardization for means (or first moments) of exogenous variables, and it is a more direct analogue t...
Asymptotic behavior of atomic momentals
Thakkar, Ajit J.
1987-05-01
Knowledge of the large and small momentum transfer behavior of the electron momentum distribution is an important ingredient in the analysis of experimental isotropic Compton profiles. This behavior ultimately rests upon the asymptotic behavior of atomic momentals (momentum space orbitals). The small momentum Maclaurin expansion and the large momentum asymptotic expansion of atomic momentals with arbitrary angular momentum quantum number are derived in this paper. Their implications for momentum densities and Compton profiles are derived and discussed.
Fast computation of Krawtchouk moments
Czech Academy of Sciences Publication Activity Database
Honarvar Shakibaei Asli, B.; Flusser, Jan
2014-01-01
Roč. 288, č. 1 (2014), s. 73-86. ISSN 0020-0255 R&D Projects: GA ČR GAP103/11/1552 Institutional support: RVO:67985556 Keywords : Krawtchouk polynomial * Krawtchouk moment * Geometric moment * Impulse response * Fast computation * Digital filter Subject RIV: JD - Computer Applications, Robotics Impact factor: 4.038, year: 2014 http://library.utia.cas.cz/separaty/2014/ZOI/flusser-0432452.pdf
Moment Distributions of Phase Type
DEFF Research Database (Denmark)
Bladt, Mogens; Nielsen, Bo Friis
2011-01-01
Moment distributions of phase-type and matrix-exponential distributions are shown to remain within their respective classes. We provide a probabilistic phase-type representation for the former case and an alternative representation, with an analytically appealing form, for the latter. First order...... moment distributions are of special interest in areas like demography and economics, and we calculate explicit formulas for the Lorenz curve and Gini index used in these disciplines....
Institute of Scientific and Technical Information of China (English)
Audrey
2008-01-01
@@ Chinese people would never for-get the moment-14:28, on May 12, 2008, as the 8.0-magnitude earthquake shook the whole of Sichuan; at that moment the world's at-tention was focused on the southwest of China - the homeland of the Giant Panda. This rare yet catastrophic natural disaster has resulted in the heavy loss of lives and property throughout the region.
Coupled Torsional and Bending Vibrations of Actively Controlled Drillstrings
YIGIT, A. S.; CHRISTOFOROU, A. P.
2000-06-01
The dynamics of actively controlled drillstrings is studied. The equations of motion are derived using a lumped parameter model in which the coupling between torsional and bending vibrations is considered. The model also includes the dynamics of the rotary drive system which contains the rotary table, the gearbox and an armature controlled DC motor. The interactions between the drillstring and the borehole which are considered, include the impacts of collars with the borehole wall as well as bit rotation-dependent weight and torque on bit (WOB and TOB). Simulation results obtained by numerically solving the equations of motion are in close qualitative agreement with field and laboratory observations regarding stick-slip oscillations. A linear quadratic regulator (LQR) controller is designed based on a linearized model and is shown to be effective in eliminating this type of oscillations. It is also shown that for some operational parameters the control action may excite large bending vibrations due to coupling with the torsional motion.
Directory of Open Access Journals (Sweden)
Jay Foster
2015-11-01
Full Text Available At least two recent collections of essays – Postmodernism and the Enlightenment (2001 and What’s Left of Enlightenment?: A Postmodern Question (2001 – have responded to postmodern critiques of Enlightenment by arguing that Enlightenment philosophes themselves embraced a number of post-modern themes. This essay situates Kant’s essay Was ist Aufklärung (1784 in the context of this recent literature about the appropriate characterization of modernity and the Enlightenment. Adopting an internalist reading of Kant’s Aufklärung essay, this paper observes that Kant is surprisingly ambivalent about who might be Enlightened and unspecific about when Enlightenment might be achieved. The paper argues that this is because Kant is concerned less with elucidating his concept of Enlightenment and more with characterizing a political condition that might provide the conditions for the possibility of Enlightenment. This paper calls this political condition modernity and it is achieved when civil order can be maintained alongside fractious and possibly insoluble public disagreement about matters of conscience, including the nature and possibility of Enlightenment. Thus, the audience for the Aufklärung essay is not the tax collector, soldier or clergyman, but rather the sovereign. Kant enjoins and advises the prince that discord and debate about matters of conscience need not entail any political unrest or upheaval. It is in this restricted (Pocockian sense that the Enlightenment essay is Kant’s Machiavellian moment.
Estimation of tensile properties of pipe bends manufactured by cold bending
International Nuclear Information System (INIS)
In this study, tensile tests were performed on specimens that simulated the cold bending and heat treatment of pipe bends to understand the mechanical properties of pipe bends manufactured by cold bending followed by heat treatment for relieving residual stress. The strength and ductility of cold worked materials were respectively found to be higher and lower than those of the parent material although heat treatment was carried out to relieve residual stress. In addition, the increase in strength and decrease in ductility were proportional to the applied strain levels for cold working. It was thus inferred that the intrados and extrados regions of pipe bends that were cold bended and heat treated show higher strength and lower ductility compared to the parent straight pipe and that the mechanical properties at the crown region are nearly the same as those of the parent straight pipe
This is a slice of a LEP dipole bending magnet, made as a concrete and iron sandwich. The bending field needed in LEP is small (about 1000 Gauss), equivalent to two of the magnets people stick on fridge doors. Because it is very difficult to keep a low field steady, a high field was used in iron plates embedded in concrete. A CERN breakthrough in magnet design, LEP dipoles can be tuned easily and are cheaper than conventional magnets.
Pipes under internal pressure and bending
Catinaccio, A
2009-01-01
This article covers the general behaviour of a straight uniform pipe, with built-in open ends, subject to internal pressure and in plane bending or curvature. It is intended as a summary of the basic equations driving the unintuitive phenomena of bending and instability of pipes under internal pressure. The analysis covers in addition the investigation of opposite pressure stabilisation effects that can be observed in some orthotropic material pipes like composite pressure hoses.
Elliott, Mark A; Giersch, Anne
2015-01-01
There has been evidence for the very brief, temporal quantization of perceptual experience at regular intervals below 100 ms for several decades. We briefly describe how earlier studies led to the concept of "psychological moment" of between 50 and 60 ms duration. According to historical theories, within the psychological moment all events would be processed as co-temporal. More recently, a link with physiological mechanisms has been proposed, according to which the 50-60 ms psychological moment would be defined by the upper limit required by neural mechanisms to synchronize and thereby represent a snapshot of current perceptual event structure. However, our own experimental developments also identify a more fine-scaled, serialized process structure within the psychological moment. Our data suggests that not all events are processed as co-temporal within the psychological moment and instead, some are processed successively. This evidence questions the analog relationship between synchronized process and simultaneous experience and opens debate on the ontology and function of "moments" in psychological experience. PMID:26779059
Bending rigidity of composite resin coating clasps.
Ikebe, K; Kibi, M; Ono, T; Nokubi, T
1993-12-01
The purpose of this study is to examine the bending profiles of composite resin coating cast clasps. The cobalt-chromium alloy cast clasps were made using tapered wax pattern. Silane coupling method (Silicoater MD, Kulzer Co.) was used to attach composite resin to metal surface. The breakage and the bending rigidity of composite resin coating clasps were evaluated. Results were as follows: 1) After the repeated bending test to the tips of clasp arm at 10,000 times in 0.25 mm deflection, neither crack on composite resin surface nor separation at resin/metal interface was observed in any specimen. 2) There was no significant difference in the bending rigidity of clasp arms between before and after composite resin coating. From these results, it was demonstrated that the composite resin coating cast clasp was available in clinical cases and coating with composite resin had little influence on the bending rigidity of clasp arms. Therefore, it was suggested that our clasp designing and fabricating system to control the bending rigidity of clasp arms could be applied to composite resin coating clasps. PMID:8935086
A transparent bending-insensitive pressure sensor
Lee, Sungwon; Reuveny, Amir; Reeder, Jonathan; Lee, Sunghoon; Jin, Hanbit; Liu, Qihan; Yokota, Tomoyuki; Sekitani, Tsuyoshi; Isoyama, Takashi; Abe, Yusuke; Suo, Zhigang; Someya, Takao
2016-05-01
Measuring small normal pressures is essential to accurately evaluate external stimuli in curvilinear and dynamic surfaces such as natural tissues. Usually, sensitive and spatially accurate pressure sensors are achieved through conformal contact with the surface; however, this also makes them sensitive to mechanical deformation (bending). Indeed, when a soft object is pressed by another soft object, the normal pressure cannot be measured independently from the mechanical stress. Here, we show a pressure sensor that measures only the normal pressure, even under extreme bending conditions. To reduce the bending sensitivity, we use composite nanofibres of carbon nanotubes and graphene. Our simulations show that these fibres change their relative alignment to accommodate bending deformation, thus reducing the strain in individual fibres. Pressure sensitivity is maintained down to a bending radius of 80 μm. To test the suitability of our sensor for soft robotics and medical applications, we fabricated an integrated sensor matrix that is only 2 μm thick. We show real-time (response time of ∼20 ms), large-area, normal pressure monitoring under different, complex bending conditions.
Microbial hotspots and hot moments in soil
Kuzyakov, Yakov; Blagodatskaya, Evgenia
2015-04-01
Soils are the most heterogeneous parts of the biosphere, with an extremely high differentiation of properties and processes within nano- to macroscales. The spatial and temporal heterogeneity of input of labile organics by plants creates microbial hotspots over short periods of time - the hot moments. We define microbial hotspots as small soil volumes with much faster process rates and much more intensive interactions compared to the average soil conditions. Such hotspots are found in the rhizosphere, detritusphere, biopores (including drilosphere) and on aggregate surfaces, but hotspots are frequently of mixed origin. Hot moments are short-term events or sequences of events inducing accelerated process rates as compared to the averaged rates. Thus, hotspots and hot moments are defined by dynamic characteristics, i.e. by process rates. For this hotspot concept we extensively reviewed and examined the localization and size of hotspots, spatial distribution and visualization approaches, transport of labile C to and from hotspots, lifetime and process intensities, with a special focus on process rates and microbial activities. The fraction of active microorganisms in hotspots is 2-20 times higher than in the bulk soil, and their specific activities (i.e. respiration, microbial growth, mineralization potential, enzyme activities, RNA/DNA ratio) may also be much higher. The duration of hot moments in the rhizosphere is limited and is controlled by the length of the input of labile organics. It can last a few hours up to a few days. In the detritusphere, however, the duration of hot moments is regulated by the output - by decomposition rates of litter - and lasts for weeks and months. Hot moments induce succession in microbial communities and intense intra- and interspecific competition affecting C use efficiency, microbial growth and turnover. The faster turnover and lower C use efficiency in hotspots counterbalances the high C inputs, leading to the absence of strong
New Equation for Bending Development of Arbitrary Rods and Application to Palm Fronds Bending
Abdullah, Mikrajuddin
2016-01-01
A new general equation to explain bending of arbitrary rods (from arbitrary materials, cross sections, densities, strengthnesses, bending angles, etc) was proposed. This equation can solve several problems found in classical equations, which have many limitations such as only applies for small bending angles or must be solved using very complex schemes. Experiments were also conducted to confirm the theoretical predictions. The equation might be used to explain bending of palm fronds in a very simple way. The proposed equation may be used to obtain solution of several problems which are usually obtain with iteration procedures.
Normalization of ground reaction forces, joint moments, and free moments in human locomotion.
Wannop, John W; Worobets, Jay T; Stefanyshyn, Darren J
2012-12-01
Authors who report ground reaction force (GRF), free moment (FM), and resultant joint moments usually normalize these variables by division normalization. Normalization parameters include body weight (BW), body weight x height (BWH), and body weight x leg length (BWL). The purpose of this study was to explore the appropriateness of division normalization, power curve normalization, and offset normalization on peak GRF, FM, and resultant joint moments. Kinematic and kinetic data were collected on 98 subjects who walked at 1.2 and 1.8 m/s and ran at 3.4 and 4.0 m/s. Linear curves were best fit to the data, and regression analyses performed to test the significance of the correlations. It was found that the relationship between peak force and BW, as well as joint moments and BW, BWH, and BWL, were not always linear. After division normalization, significant correlations were still found. Power curve and offset normalization, however, were effective at normalizing all variables; therefore, when attempting to normalize GRF and joint moments, perhaps nonlinear or offset methods should be implemented. PMID:23348130
Martirosyan K.L.; Darbinyan A.Z.
2015-01-01
In this article is investigated the action the transversal shears the problem of plate bending semi-infinite plates when two opposite edges are simply supported boundary conditions. The problem of bending of a plate the action of tangential loads is considered on the base of classical theory[1], on the base of refined theory of first order, on the base of refined theory of high order. The comparisons between deflections, crosscutting forces and moments by theory of Reissner-Genki-Mindlin by V...
Directory of Open Access Journals (Sweden)
Martirosyan K.L.
2015-09-01
Full Text Available In this article is investigated the action the transversal shears the problem of plate bending semi-infinite plates when two opposite edges are simply supported boundary conditions. The problem of bending of a plate the action of tangential loads is considered on the base of classical theory[1], on the base of refined theory of first order, on the base of refined theory of high order. The comparisons between deflections, crosscutting forces and moments by theory of Reissner-Genki-Mindlin by Vasilyev variant [2], and the theory of Ambartsumyan [3].
Performance of Object Classification Using Zernike Moment
Institute of Scientific and Technical Information of China (English)
Ariffuddin Joret; Mohammad Faiz Liew Abdullah; Muhammad Suhaimi Sulong; Asmarashid Ponniran; Siti Zuraidah Zainudin
2014-01-01
Moments have been used in all sorts of object classification systems based on image. There are lots of moments studied by many researchers in the area of object classification and one of the most preference moments is the Zernike moment. In this paper, the performance of object classification using the Zernike moment has been explored. The classifier based on neural networks has been used in this study. The results indicate the best performance in identifying the aggregate is at 91.4% with a ten orders of the Zernike moment. This encouraging result has shown that the Zernike moment is a suitable moment to be used as a feature of object classification systems.
Waveguide Bend of 90° in Two-Dimensional Triangular Lattice Silicon Photonic Crystal Slabs
International Nuclear Information System (INIS)
We design and realize a 90° waveguide bend in two-dimensional triangular lattice silicon photonic crystal slabs by connecting linear waveguides along the orthogonal Γ – K and Γ – M directions. A pass band of 70 nm is realized by optimizing the geometry of the Γ – M waveguide. The connection region of the waveguide bend is optimized to improve the transmission efficiency of infrared light through the two different kinds of waveguides. The transmission efficiency of an optimized single bend is about 75% in simulation and 45% in measurement. (fundamental areas of phenomenology (including applications))
Directory of Open Access Journals (Sweden)
Francisco de Oliveira
2007-01-01
Full Text Available After tracing the path taken by the Partido dos Trabalhadores (Workers’ Party to the Presidency of Brazil, Francisco de Oliveira describes how the first years of the PT adminstration, which continued on the same footing as the previous government, relate to a broader context characterized by the consequences of the ascendancy of finance capital: the impossibility of hegemony due to the increasing chasm between rich and poor; the decomposition of class bases, including that of the bourgeoisie due to the antagonism between financial and industrial capital; emergent populism; and finally the incorporation of parties and politics into the State, even as the economy and daily life are increasingly privatized.
Analytical dynamic modeling of fast trilayer polypyrrole bending actuators
International Nuclear Information System (INIS)
Analytical modeling of conjugated polymer actuators with complicated electro-chemo-mechanical dynamics is an interesting area for research, due to the wide range of applications including biomimetic robots and biomedical devices. Although there have been extensive reports on modeling the electrochemical dynamics of polypyrrole (PPy) bending actuators, mechanical dynamics modeling of the actuators remains unexplored. PPy actuators can operate with low voltage while producing large displacement in comparison to robotic joints, they do not have friction or backlash, but they suffer from some disadvantages such as creep and hysteresis. In this paper, a complete analytical dynamic model for fast trilayer polypyrrole bending actuators has been proposed and named the analytical multi-domain dynamic actuator (AMDDA) model. First an electrical admittance model of the actuator will be obtained based on a distributed RC line; subsequently a proper mechanical dynamic model will be derived, based on Hamilton's principle. The purposed modeling approach will be validated based on recently published experimental results
Drabik, Dominik; Przybyło, Magda; Chodaczek, Grzegorz; Iglič, Aleš; Langner, Marek
2016-02-01
Lipid bilayer is the main constitutive element of biological membrane, which confines intracellular space. The mechanical properties of biological membranes may be characterized by various parameters including membrane stiffness or membrane bending rigidity, which can be measured using flicker noise spectroscopy. The flicker noise spectroscopy exploits the spontaneous thermal undulations of the membrane. The method is based on the quantitative analysis of a series of microscopic images captured during thermal membrane fluctuations. Thus, measured bending rigidity coefficient depends on the image quality as well as the selection of computational tools for image processing and mathematical model used. In this work scanning and spinning disc confocal microscopies were used to visualize fluctuating membranes of giant unilamellar vesicles. The bending rigidity coefficient was calculated for different acquisition modes, using different fluorescent probes and different image processing methods. It was shown that both imaging approaches gave similar bending coefficient values regardless of acquisition time. Using the developed methodology the effect of fluorescent probe type and aqueous phase composition on the value of the membrane bending rigidity coefficient was measured. Specifically it was found that the bending rigidity coefficient of DOPC bilayer in water is smaller than that determined for POPC membrane. It has been found that the POPC and DOPC bending rigidities coefficient in sucrose solution was lower than that in water. Fluorescence imaging makes possible the quantitative analysis of membrane mechanical properties of inhomogeneous membrane. PMID:26615919
Flexible thick-film glucose biosensor: influence of mechanical bending on the performance.
Chuang, Min-Chieh; Yang, Yang-Li; Tseng, Ta-Feng; Chou, Tzuyang; Lou, Shyh-Liang; Wang, Joseph
2010-04-15
The influence of the bending-induced mechanical stress of flexible Nafion/GOx/carbon screen-printed electrodes (SPEs) upon the performance of such glucose biosensors has been examined. Surprisingly, such flexible enzyme/polymer-SPEs operate well following a severe bending-induced mechanical stress (including a 180 degrees pinch), and actually display a substantial sensitivity enhancement following their mechanical bending. The bending-induced sensitivity enhancement is observed only for the amperometric detection of the glucose substrate but not for measurements of hydrogen peroxide, catechol or ferrocyanide at coated or bare SPEs. These (and additional) data indicate that the bending effect is associated primarily with changes in the biocatalytic activity. Such sensitivity enhancement is more pronounced at elevated glucose levels, reflecting the bending-induced changes in the biocatalytic reaction. Factors affecting the bending-induced changes in the performance are examined. While our data clearly indicate that flexible enzyme/polymer-SPEs can tolerate a severe mechanical stress and hold promise as wearable glucose biosensors, delivering the sample to the active sensor surface remains the major challenge for such continuous health monitoring. PMID:20188880
Radiation reaction for multipole moments
Kazinski, P O
2006-01-01
We propose a Poincare-invariant description for the effective dynamics of systems of charged particles by means of intrinsic multipole moments. To achieve this goal we study the effective dynamics of such systems within two frameworks -- the particle itself and hydrodynamical one. We give a relativistic-invariant definition for the intrinsic multipole moments both pointlike and extended relativistic objects. Within the hydrodynamical framework we suggest a covariant action functional for a perfect fluid with pressure. In the case of a relativistic charged dust we prove the equivalence of the particle approach to the hydrodynamical one to the problem of radiation reaction for multipoles. As the particular example of a general procedure we obtain the effective model for a neutral system of charged particles with dipole moment.
Sharp bends of phononic crystal surface modes
Cicek, Ahmet; Salman, Aysevil; Adem Kaya, Olgun; Ulug, Bulent
2015-12-01
Sharp bending of surface waves at the interface of a two-dimensional phononic crystal (PnC) of steel cylinders in air and the method of using a diagonally offset cylindrical scatterer are numerically demonstrated by finite-element method simulations. The radii of the diagonally offset scatterer and the cylinder at the PnC corner, along with the distance between them, are treated as optimization parameters in the genetic algorithm optimization of sharp bends. Surface wave transmittance of at most 5% for the unmodified sharp bend is significantly enhanced to approximately 75% as a result of optimization. A series of transmittance peaks whose maxima increase exponentially, as their widths reduce, with increasing frequency is observed for the optimized sharp bend. The transmittance peaks appear at frequencies corresponding to integer plus half-beat periods, depending on the finite surface length. The optimal parameters are such that the cylinder radius at the PnC corner is not significantly modified, whereas a diagonally offset scatterer having a diameter of almost two periods and a shortest distance of about 0.7 periods between them is required for the strongest transmittance peak. Utilization of PnC surface sharp bends as acoustic ring resonators is demonstrated.
Sharp bends of phononic crystal surface modes
International Nuclear Information System (INIS)
Sharp bending of surface waves at the interface of a two-dimensional phononic crystal (PnC) of steel cylinders in air and the method of using a diagonally offset cylindrical scatterer are numerically demonstrated by finite-element method simulations. The radii of the diagonally offset scatterer and the cylinder at the PnC corner, along with the distance between them, are treated as optimization parameters in the genetic algorithm optimization of sharp bends. Surface wave transmittance of at most 5% for the unmodified sharp bend is significantly enhanced to approximately 75% as a result of optimization. A series of transmittance peaks whose maxima increase exponentially, as their widths reduce, with increasing frequency is observed for the optimized sharp bend. The transmittance peaks appear at frequencies corresponding to integer plus half-beat periods, depending on the finite surface length. The optimal parameters are such that the cylinder radius at the PnC corner is not significantly modified, whereas a diagonally offset scatterer having a diameter of almost two periods and a shortest distance of about 0.7 periods between them is required for the strongest transmittance peak. Utilization of PnC surface sharp bends as acoustic ring resonators is demonstrated. (paper)
Pure plate bending in couple stress theories
Hadjesfandiari, Ali R; Dargush, Gary F
2016-01-01
In this paper, we examine the pure bending of plates within the framework of modified couple stress theory (M-CST) and consistent couple stress theory (C-CST). In this development, it is demonstrated that M-CST does not describe pure bending of a plate properly. Particularly, M-CST predicts no couple-stresses and no size effect for the pure bending of the plate into a spherical shell. This contradicts our expectation that couple stress theory should predict some size effect for such a deformation pattern. Therefore, this result clearly demonstrates another inconsistency of indeterminate symmetric modified couple stress theory (M-CST), which is based on considering the symmetric torsion tensor as the curvature tensor. On the other hand, the fully determinate skew-symmetric consistent couple stress theory (C-CST) predicts results for pure plate bending that tend to agree with mechanics intuition and experimental evidence. Particularly, C-CST predicts couple-stresses and size effects for the pure bending of the ...
Tunable thermoelectric properties in bended graphene nanoribbons
Institute of Scientific and Technical Information of China (English)
潘长宁; 何军; 方卯发
2016-01-01
The ballistic thermoelectric properties in bended graphene nanoribbons (GNRs) are systematically investigated by using atomistic simulation of electron and phonon transport. We find that the electron resonant tunneling effect occurs in the metallic–semiconducting linked ZZ-GNRs (the bended GNRs with zigzag edge leads). The electron-wave quan-tum interference effect occurs in the metallic–metallic linked AA-GNRs (the bended GNRs with armchair edge leads). These different physical mechanisms lead to the large Seebeck coefficient S and high electron conductance in bended ZZ-GNRs/AA-GNRs. Combined with the reduced lattice thermal conduction, the significant enhancement of the figure of merit ZT is predicted. Moreover, we find that the ZTmax (the maximum peak of ZT) is sensitive to the structural parameters. It can be conveniently tuned by changing the interbend length of bended GNRs. The magnitude of ZT ranges from the 0.15 to 0.72. Geometry-controlled ballistic thermoelectric effect offers an effective way to design thermoelectric devices such as thermocouples based on graphene.
Aristizabal-Ochoa, Jose Dario
2012-01-01
Closed-form expressions that can be used to evaluate the induced elastic bending moments and second-order deflections in slender prismatic columns with initial geometric imperfections (i.e., initial curvature and out-of-plumbness) and semirigid connections when subjected to eccentric axial loads at both ends are derived in a classical manner. The proposed approach is based on the classical Euler-Bernoulli theory for columns with sidesway uninhibited, partially inhibited, and totally inhibited...
The unity of instantaneous spectral moments and physical moments
Lilly, Jonathan M
2012-01-01
A modulated oscillation in two or three dimensions can be represented as the trajectory traced out in space by a particle orbiting an ellipse, the properties of which vary as a function of time. Generalizing ideas from signal analysis, the signal variability can be described in terms of kinematic quantities, the instantaneous moments, that formalize our intuitive notions of time-varying frequency and amplitude. On the other hand, if we observed an ellipse evolving in space we would seek to describe it in terms of its physical moments, such as angular momentum, moment of inertia, etc. The main result of this paper is to show that the two sets of moments are identical. Most significantly, an essential physical quantity---the circulation---is the same as the product of the two most important kinematic quantities, the instantaneous frequency and the squared instantaneous amplitude. In addition to providing a rich set of geometric tools for the analysis of nonstationary oscillations in two or three dimensions, thi...
Summers, Richard F; Kreider, Timothy R
2014-02-01
The rollout of DSM-5 is both a challenge and an opportunity for psychiatrists and particularly for trainees. Psychiatric education in the wake of DSM-5 will go beyond memorizing lists of new criteria. Teachers and learners alike will seize the "teachable moment" to learn new content, model how to approach and apply new understanding, think about how new knowledge is developed, and appreciate the importance of public dialogue.We can capitalize on this moment to improve the teaching of assessment skills as a central focus of residency training. PMID:24419821
Multipole moments for embedding potentials
DEFF Research Database (Denmark)
Nørby, Morten Steen; Olsen, Jógvan Magnus Haugaard; Kongsted, Jacob;
2016-01-01
and RNA/DNA, and of molecules in solution. Our aim is to develop a computational methodology for distributed multipole moments and their associated multipole polarizabilities which is accurate, computationally efficient, and with smooth convergence with respect to multipole order. As the first step...... toward this goal, we herein investigate different ways of obtaining distributed atom-centered multipole moments that are used in the construction of the electrostatic part of the embedding potential. Our objective is methods that not only are accurate and computationally efficient, but which can be...
Method of moments in electromagnetics
Gibson, Walton C
2007-01-01
Responding to the need for a clear, up-to-date introduction to the field, The Method of Moments in Electromagnetics explores surface integral equations in electromagnetics and presents their numerical solution using the method of moments (MOM) technique. It provides the numerical implementation aspects at a nuts-and-bolts level while discussing integral equations and electromagnetic theory at a higher level. The author covers a range of topics in this area, from the initial underpinnings of the MOM to its current applications. He first reviews the frequency-domain electromagnetic theory and t
Lagrangian magnetic moment from polarization
Braghin, Fabio L
2016-01-01
An effective Lagrangian term for the electron magnetic moment, and more generally electromagnetic form factors, is calculated by considering the background field method. Two Fierz transformations are performed for a one-photon exchange interaction, and the ambiguity in doing such transformations is exploited. The resulting effective interaction may exhibit an approximated rotational chiral symmetry either for the scalar-pseudoscalar currents interaction or for the vector-axial currents interaction. The leading terms in the expansion of the fermion determinant yield the leading QED effective action with the complete one loop electromagnetic form factors. A model is proposed to produce the tree level magnetic moment term.
Bending Analysis of Symmetrically Laminated Plates
Directory of Open Access Journals (Sweden)
Bouazza MOKHTAR
2010-12-01
Full Text Available In the classical plate theory, it is assumed that the plane cross sections initially normal to the plate midsurface before deformation remain plane and normal to that surface during deformation. This is the result of neglecting the transverse shear strains. However, in thick and moderately thick laminated plates, significant transverse shear strains occur, and the theory gives inaccurate results for the plates. So, it is obvious that the shear strains have to be taken into account. There are numerous theories of plates and laminated plates that include the transverse shear strains. One of them is the Reissner and Midlin theory , known as the first-order shear deformation theory, which defines the displacement field as linear variations of midplane displacements. This theory, where the relation between the resultant shear forces and the shear strains is obtained by using shear correction factors, has some advantages due to its simplicity and low computational cost. Some other plate theories, namely the higher-order shear deformation theories, include the effect of transverse shear strains . For example, the theory developed by Reddy allows not only for the transverse shear strains, but also for parabolic variations in the strains across the plate thickness, and thus there is no need to use shear correction coefficients in computing the shear stresses. The present stud is a survey of plate bending of cross-ply laminate by using the finite element method (F.E.M. Using ANSYS, the most known software in the domain for it, two types of modeling are proposed: the first is modeling using a type of shell element, Shell 99 and the second is an approach based on a of type solid element, Solid 46. The results obtained are compared with the results of the theory of Reddy.
Hanzon, Drew Wyatt
This work consists on the quantification of sheet metal uniaxial stress-strain reversals from pure bending tests. Bending strains to approximately 10% were measured by strain gages and interferometry. Bending-unbending moments and strains were modeled and compared closely to the experimental data. The reverse uniaxial stress-strains curves were determined from the optimal fit of the model. Bauschinger effects were described by the reverse uniaxial response at the elasto-plastic range, between the elastic and the large strain, power fit ranges. Arc and straight line fittings on the lnsigma-lnepsilon scale proved accurate to describe the elasto-plastic behavior. Reverse uniaxial data determined for DP590 and DP780 steels and two Aluminum alloys showed significant Bauschinger effects with distinct features. For the DP steels the magnitudes of the reverse compressive sigma-epsilon curves compared moderately higher, and merging to a power curve with parameters K, n previously defined by tension testing. Bauschinger effects at small reversed strains were less pronounced for the aluminum alloys. However, at higher strains the reverse elasto-plastic response softened considerably, and during the unbending span the magnitudes of the reverse compressive strains remained below the corresponding K, n tensile values. The results showed pure bending as an efficient, simple to use technique to generate sigma-epsilon data for sheet metal at large reverse strains without the complicating restraining hardware required by direct compression methods.
An optical fibre sensor for physiological bending monitoring in clinical environment
Zawawi, Mohd Anwar
2015-01-01
peer-reviewed Health monitoring applications in clinical environment include various areas such as respiration assessment, heart rate monitoring, gait monitoring, spine bending as well as lower and upper limb motion detections. In human spine monitoring application, static and dynamic assessments of the spine bending are important and are generally preferrable as routine diagnostic procedures among chronic and acute low back pain patients. Many accurate and highly reliable devices are wide...
Sayyad A. S.; Ghugal Y. M.; Naik N. S.
2015-01-01
A trigonometric beam theory (TBT) is developed for the bending analysis of laminated composite and sandwich beams considering the effect of transverse shear deformation. The axial displacement field uses trigonometric function in terms of thickness coordinate to include the effect of transverse shear deformation. The transverse displacement is considered as a sum of two partial displacements, the displacement due to bending and the displacement due to transverse sheari...
Experimental Research and Numerical Simulation of Wing Boxes under Pure Bending Load
Peiyan Wang; Shile Yao; Xinmei Wang; Zhufeng Yue
2014-01-01
Two full-scale wing boxes with different types of butt joints were investigated under pure bending load, and numerical methods, including global analysis and detailed analysis, were proposed to determine the reasons for failure of the wing boxes. Wing boxes were tested under bending loads applied by a multichannel force control system. The experimental results showed that the region of the butt joint was the weakest location of the wing boxes, and the damage loads were far less than the desig...
Moments of inertia and the shapes of Brownian paths
International Nuclear Information System (INIS)
The joint probability law of the principal moments of inertia of Brownian paths (open or closed) is computed, using constrained path integrals and Random Matrix Theory. The case of two-dimensional paths is discussed in detail. In particular, it is shown that the ratio of the average values of the largest and smallest moments is equal to 4.99 (open paths) and 3.07 (closed paths). Results of numerical simulations are also presented, which include investigation of the relationships between the moments of inertia and the arithmetic area enclosed by a path. (authors) 28 refs., 2 figs
Moments of inertia and the shapes of Brownian paths
Energy Technology Data Exchange (ETDEWEB)
Fougere, F.; Desbois, J.
1993-12-31
The joint probability law of the principal moments of inertia of Brownian paths (open or closed) is computed, using constrained path integrals and Random Matrix Theory. The case of two-dimensional paths is discussed in detail. In particular, it is shown that the ratio of the average values of the largest and smallest moments is equal to 4.99 (open paths) and 3.07 (closed paths). Results of numerical simulations are also presented, which include investigation of the relationships between the moments of inertia and the arithmetic area enclosed by a path. (authors) 28 refs., 2 figs.
Analysis and experiments for composite laminates with holes and subjected to 4-point bending
Shuart, M. J.; Prasad, C. B.
1990-01-01
Analytical and experimental results are presented for composite laminates with a hole and subjected to four-point bending. A finite-plate analysis is used to predict moment and strain distributions for six-layer quasi-isotropic laminates and transverse-ply laminates. Experimental data are compared with the analytical results. Experimental and analytical strain results show good agreement for the quasi-isotropic laminates. Failure of the two types of composite laminates is described, and failure strain results are presented as a function of normalized hole diameter. The failure results suggest that the initial failure mechanism for laminates subjected to four-point bending are similar to the initial failure mechanisms for corresponding laminates subjected to uniaxial inplane loadings.
Fatigue Assessment of High Strength Steel Welded Joints Under Bending Loading
International Nuclear Information System (INIS)
In this study, a fatigue assessment method for vehicle suspension systems having welded geometries was established under a bending loading condition. For the fatigue life estimation of the actual products welded joints made of different steels, bending fatigue tests were performed on welded specimens with a simplified shape for obtaining the moment-fatigue-life plot. Further, geometry modeling of the simplified welded specimens was conducted. Results of finite element analysis were used to obtain the stress-fatigue-life plot. The analysis results were also used to calculate the stress concentration factors for notch-factor-based fatigue life estimation. The test results were compared with results of the general notch-factor-based fatigue life estimation for improving fatigue assessment. As a result, it was concluded that both the welded fatigue tests and the notch-factor-based fatigue life estimation are necessary for accurate fatigue assessment
Biomorphodynamic modelling of inner bank advance in migrating meander bends
Zen, Simone; Zolezzi, Guido; Toffolon, Marco; Gurnell, Angela M.
2016-07-01
We propose a bio-morphodynamic model at bend cross-sectional scale for the lateral migration of river meander bends, where the two banks can migrate separately as a result of the mutual interaction between river flow, sediments and riparian vegetation, particularly at the interface between the permanently wet channel and the advancing floodplain. The model combines a non-linear analytical model for the morphodynamic evolution of the channel bed, a quasi-1D model to account for flow unsteadiness, and an ecological model describing riparian vegetation dynamics. Simplified closures are included to estimate the feedbacks among vegetation, hydrodynamics and sediment transport, which affect the morphology of the river-floodplain system. Model tests reveal the fundamental role of riparian plants in generating bio-morphological patterns at the advancing floodplain margin. Importantly, they provide insight into the biophysical controls of the 'bar push' mechanism and into its role in the lateral migration of meander bends and in the temporal variations of the active channel width.
A missing-bending-magnet scheme for PEP
International Nuclear Information System (INIS)
This article presents a missing-bending-magnet scheme for PEP as a modification that could be considered if PEP were available as a fully dedicated synchrotron radiation source. The scheme can be applied to one or more PEP sextants without changing the rest. By removing some bending magnets, rearranging the remaining magnets, and adding two quadrupoles, ten additional straight sections per sextant can be created, each 5 m or more in length, for insertion devices. Beam lines therefrom, plus possible beam lines from bending magnets would enter a continuous experimental hall instead of individual tunnels and halls for each beam line. This should result in construction cost savings and increased operations efficiency. The ideal beam orbit is unchanged at the two ends and the middle of the sextant. At the end of the curved part of the sextant the lattice functions match those of the long interaction region straight section in the low emittance configuration of PEP. The electron beam characteristics in the newly created straight sections are described, including the enlargement of the horizontal beam size due to the nonzero dispersion. Some disadvantages of the scheme are increased operations complexity due to the need for nine new quadrupole families, increased beam emittance (by 14.5% is one sextant is modified), and reduced dynamic aperture. However, the dynamic aperture is still about as large as the physical aperture and should be adequate for good beam lifetime and injection. (orig.)
Moment of Inertia by Differentiation
Rizcallah, Joseph A.
2015-01-01
The calculation of the moment of inertia of an extended body, as presented in standard introductory-level textbooks, involves the evaluation of a definite integral--an operation often not fully mastered by beginners, let alone the conceptual difficulties it presents, even to the advanced student, in understanding and setting up the integral in the…
Quiet Moment around the Campfire
Centers for Disease Control (CDC) Podcasts
2014-06-18
Byron Breedlove reads his essay, "Quiet Moment around the Campfire," about the art of Frederic Remington and the transmission of pathogens as frontiers expand. Created: 6/18/2014 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID). Date Released: 6/19/2014.
Anomalous magnetic moment of anyons
Gat, G; Gat, Gil; Ray, Rashmi
1994-01-01
The anomalous magnetic moment of anyons is calculated to leading order in a 1/N expansion. It is shown that the gyromagnetic ratio g remains 2 to the leading order in 1/N. This result strongly supports that obtained in \\cite{poly}, namely that g=2 is in fact exact.
Particle electric dipole-moments
Energy Technology Data Exchange (ETDEWEB)
Pendlebury, J.M. [Sussex Univ., Brighton (United Kingdom)
1997-04-01
The incentive to detect particle electric dipole-moments, as a window on time-reversal violation, remains undiminished. Efforts to improve the measurements for the neutron, the electron and some nuclei are still making rapid progress as more powerful experimental methods are brought to bear. A new measurement for the neutron at ILL is presented. (author). 7 refs.
Marnette, Jascha; Rolfe, Bernard; Hodgson, Peter; Weiss, Matthias
2013-12-01
The common grades of steel used in roll forming are: hot rolled, high strength low alloy and recovery annealed cold rolled sheet. These steels are prone to ageing and are often skin passed and/or roller leveled to eliminate ageing as this can lead to problems in forming. Shape defects such as bow, twist and camber can be increased due to a change of the elastic-plastic transition point of the material. In consideration of this effect the knowledge of the material properties in the elastic plastic transition range is necessary if the processes are to be modelled accurately. Previous studies have indicated that residual stresses are not well identified in the standard tensile test, but were shown clearly in a bending test. The elastic plastic transition in bending and the moment curvature characteristic were changed significantly by a light cold rolling reduction. In this work the FEA package Abaqus is used to investigate the effect of residual stresses introduced through skin passing and/or roller leveling on the bending/yielding behaviour of mild steel. Therefore, a skin passing/ roller leveling process is simulated, followed by a subsequent bending test. Residual stress free sheet is compared in bending to just "skin passed", "roller leveled" and a combined "skin passed and roller leveled" strip. Skin passing significantly reduces the bending yield stress due to residual stresses. This has a softening effect on subsequent bending operations. A roller level process prior to roll forming can restore the bending yield stress by reducing the residual stress across the thickness. This has implications for forming aged material.
Self-excited vibrations in turning: cutting moment analysis
Cahuc, Olivier; Gérard, Alain; Darnis, Philippe; Albert, Gaëtan; Bisu, Claudiu F; Gérard, Céline
2010-01-01
This work aims at analysing the moment effects at the tool tip point and at the central axis, in the framework of a turning process. A testing device in turning, including a six-component dynamometer, is used to measure the complete torsor of the cutting actions in the case of self-excited vibrations. Many results are obtained regarding the mechanical actions torsor. A confrontation of the moment components at the tool tip and at the central axis is carried out. It clearly appears that analysing moments at the central axis avoids the disturbances induced by the transport of the moment of the mechanical actions resultant at the tool tip point. For instance, the order relation between the components of the forces is single. Furthermore, the order relation between the moments components expressed at the tool tip point is also single and the same one. But at the central axis, two different order relations regarding moments are conceivable. A modification in the rolling moment localization in the (y, z) tool plan ...
Vaughan, Patrick E; Orth, Michael W; Haut, Roger C; Karcher, Darrin M
2016-01-01
While conventional mechanical testing has been regarded as a gold standard for the evaluation of bone heath in numerous studies, with recent advances in medical imaging, virtual methods of biomechanics are rapidly evolving in the human literature. The objective of the current study was to evaluate the feasibility of determining the elastic and failure properties of poultry long bones using established methods of analysis from the human literature. In order to incorporate a large range of bone sizes and densities, a small number of specimens were utilized from an ongoing study of Regmi et al. (2016) that involved humeri and tibiae from 3 groups of animals (10 from each) including aviary, enriched, and conventional housing systems. Half the animals from each group were used for 'training' that involved the development of a regression equation relating bone density and geometry to bending properties from conventional mechanical tests. The remaining specimens from each group were used for 'testing' in which the mechanical properties from conventional tests were compared to those predicted by the regression equations. Based on the regression equations, the coefficients of determination for the 'test' set of data were 0.798 for bending bone stiffness and 0.901 for the yield (or failure) moment of the bones. All regression slopes and intercepts values for the tests versus predicted plots were not significantly different from 1 and 0, respectively. The study showed the feasibility of developing future methods of virtual biomechanics for the evaluation of poultry long bones. With further development, virtual biomechanics may have utility in future in vivo studies to assess laying hen bone health over time without the need to sacrifice large groups of animals at each time point. PMID:26794840
Effect of High Impact or Non-impact Loading Activity on Bone Bending Stiffness and Mineral Density
Liang, Michael T. C.; Arnnud, Sara B.; Steele, Charles R.; Moreno, Alexjandro
2003-01-01
Material properties of conical bone, including mineral density (BMD) and its geometry is closely related to its load-carrying capacity. These two primary components determine the strength of conical bone. High impact loading involving acceleration and deceleration movements used in gymnastics induce higher BMD of the affected bone compared to the non-impact acceleration and deceleration movements used in swimming. Study of these two groups of athletes on bone bending stiffness has not been reported. The purpose of this study was to compare differences in bone bending stiffness and BMD between competitive female synchronized swimmers and female gymnasts. Thirteen world class female synchronized swimmers (SYN) and 8 female gymnasts (GYM), mean age 21 +/- 2.9 yr. were recruited for this study. We used a mechanical response tissue analyzer (Gaitscan, NJ) to calculate EI, where E is Young's modulus of elasticity and I is the cross-sectional moment of inertia. EI was obtained from tissue response to a vibration probe placed directly on the skin of the mid-region of tibia and ulna. BMD of the heel and wrist were measured with a probe densitometer (PIXI, Lunor, WI). The SYN were taller than (p < 0.05) the GYM but weighed the same as the GYM. EI obtained from tibia and ulna of the SYN (291 +/- 159 and 41 +/- 19.4, respectively) were not significantly different from thc GYM (285 +/- 140 and 44 +/- 18.3, respectively). BMD of the heel and wrist in GYM were higher than in SYN (p < 0.001). High impact weight-bearing activities promote similar bone strength but greater BMD response than non-impact activities performed in a buoyant environment.
Effect of Bend Curvature Ratio on Flow Pattern at a Mixing Tee after a 90 Degree Bend
Directory of Open Access Journals (Sweden)
Hidetoshi Hashizumeh
2009-11-01
Full Text Available Many nuclear power plants report high cycle thermal fatigue in their cooling system, caused by temperature fluctuation in a non-isothermal mixing area. One of these areas is the T-junction, in which fluids of various temperatures and velocities blend. The objective of this research is to classify turbulent jet mechanics in order to examine the flow-field structure under various operating conditions. Furthermore, this research discovers the optimum operating conditions of the mixing tee in this piping system. An experimental model, including the T-junction with a 90 degree bend upstream, is operated to analyze this mixing phenomenon based on the real operation design of the Phenix Reactor. The temperature and velocity data show that a 90 degree bend has a strong effect on the fluid mixing mechanism and the momentum ratio between the main velocity and the branch velocity of the T-junction, which could be an important parameter for the classification of the fluid mixing mechanism. By comparing their mean velocity distributions, velocity fluctuations and time-series data, the behavior of the branch jet is categorized into four types of turbulent jets; sorted from the highest to the lowest momentum ratios, the jets are categorized as follows: the wall jet, the re-attached jet, the turn jet, and the impinging jet. Ultimately, the momentum ration of the turn jet was selected as the optimum operating condition as it has the lowest velocity and the lowest temperature fluctuations near the wall of the mixing tee. By changing the bending ratio from 1.41 to 1.0 the results show that most of data are in the turn jet region. Therefore, with the sharpened bend, the re-attached region is compressed.
Bending analysis of a general cross-ply laminate using 3D elasticity solution and layerwise theory
Yazdani Sarvestani, H.; Naghashpour, A.; Heidari-Rarani, M.
2015-12-01
In this study, the analytical solution of interlaminar stresses near the free edges of a general (symmetric and unsymmetric layups) cross-ply composite laminate subjected to pure bending loading is presented based on Reddy's layerwise theory (LWT) for the first time. First, the reduced form of displacement field is obtained for a general cross-ply composite laminate subjected to a bending moment by elasticity theory. Then, first-order shear deformation theory of plates and LWT is utilized to determine the global and local deformation parameters appearing in the displacement fields, respectively. One of the main advantages of the developed solution based on the LWT is exact prediction of interlaminar stresses at the boundary layer regions. To show the accuracy of this solution, three-dimensional elasticity bending problem of a laminated composite is solved for special set of boundary conditions as well. Finally, LWT results are presented for edge-effect problems of several symmetric and unsymmetric cross-ply laminates under the bending moment. The obtained results indicate high stress gradients of interlaminar stresses near the edges of laminates.
Span-Dependent Distributions of the Bending Strength of Spruce Timber
DEFF Research Database (Denmark)
Ditlevsen, Ove; Källsner, Bo
2005-01-01
of the large test series is that unintentionally the data became randomly censored upwards. This censoring of the data rules out both the moment estimation method and the maximum likelihood method. Instead valid parameter estimates can be obtained by maximizing the posterior density defined as the...... likelihood function multiplied by a suitably chosen non-informative prior density (MP-method). Subsequently using bias factors assessed by simulation ensures that the corrected MP-estimates are unbiased. A closed form analytical expression for the distribution function of the bending strength of a beam with...
Probing the elastic limit of DNA bending
Le, Tung T
2014-01-01
Many structures inside the cell such as nucleosomes and protein-mediated DNA loops contain sharply bent double-stranded (ds) DNA. Therefore, the energetics of strong dsDNA bending constitutes an essential part of cellular thermodynamics. Although the thermomechanical behavior of long dsDNA is well described by the worm-like chain (WLC) model, the length limit of such elastic behavior remains controversial. To investigate the energetics of strong dsDNA bending, we measured the opening rate of small dsDNA loops with contour lengths of 40-200 bp using Fluorescence Resonance Energy Transfer (FRET). From the measured relationship of loop stability to loop size, we observed a transition between two separate bending regimes at a critical loop size below 100 bp. Above this loop size, the loop lifetime decreased with decreasing loop size in a manner consistent with an elastic bending stress. Below the critical loop size, however, the loop lifetime became less sensitive to loop size, indicative of softening of the doub...
Finger-jointed beams in bending
DEFF Research Database (Denmark)
Andreasen, Lotte; Hoffmeyer, Preben
1997-01-01
An investigation of the dynamic and static fatique of finger-jointed beams in bending was carried out. Results were obtained for five different frequencies from static loading to a load cycle period of two minutes. A total of seven series were long-term tested and five series were short-term tested...
Demonstration model of LEP bending magnet
CERN PhotoLab
1981-01-01
To save iron and raise the flux density, the LEP bending magnet laminations were separated by spacers and the space between the laminations was filled with concrete. This is a demonstration model, part of it with the spaced laminations only, the other part filled with concrete.
Tubular lining material for pipelines having bends
Energy Technology Data Exchange (ETDEWEB)
Moringa, A.; Sakaguchi, Y.; Hyodo, M.; Yagi, I.
1987-03-24
A tubular lining material for pipelines having bends or curved portions comprises a tubular textile jacket made of warps and wefts woven in a tubular form overlaid with a coating of a flexible synthetic resin. It is applicable onto the inner surface of a pipeline having bends or curved portions in such manner that the tubular lining material with a binder onto the inner surface thereof is inserted into the pipeline and allowed to advance within the pipeline, with or without the aid of a leading rope-like elongated element, while turning the tubular lining material inside out under fluid pressure. In this manner the tubular lining material is applied onto the inner surface of the pipeline with the binder being interposed between the pipeline and the tubular lining material. The lining material is characterized in that a part of all of the warps are comprised of an elastic yarn around which, over the full length thereof, a synthetic fiber yarn or yarns have been left-and/or right-handedly coiled. This tubular lining material is particularly suitable for lining a pipeline having an inner diameter of 25-200 mm and a plurality of bends, such as gas service pipelines or house pipelines, without occurrence of wrinkles in the lining material in a bend.
Aerosol deposition in bends with turbulent flow
Energy Technology Data Exchange (ETDEWEB)
McFarland, A.R.; Gong, H.; Wente, W.B. [Texas A& M Univ., College Station, TX (United States)] [and others
1997-08-01
The losses of aerosol particles in bends were determined numerically for a broad range of design and operational conditions. Experimental data were used to check the validity of the numerical model, where the latter employs a commercially available computational fluid dynamics code for characterizing the fluid flow field and Lagrangian particle tracking technique for characterizing aerosol losses. Physical experiments have been conducted to examine the effect of curvature ratio and distortion of the cross section of bends. If it curvature ratio ({delta} = R/a) is greater than about 4, it has little effect on deposition, which is in contrast with the recommendation given in ANSI N13.1-1969 for a minimum curvature ratio of 10. Also, experimental results show that if the tube cross section is flattened by 25% or less, the flattening also has little effect on deposition. Results of numerical tests have been used to develop a correlation of aerosol penetration through a bend as a function of Stokes number (Stk), curvature ratio ({delta}) and the bend angle ({theta}). 17 refs., 10 figs., 2 tabs.
Fuzzy model for Laser Assisted Bending Process
Directory of Open Access Journals (Sweden)
Giannini Oliviero
2016-01-01
Full Text Available In the present study, a fuzzy model was developed to predict the residual bending in a conventional metal bending process assisted by a high power diode laser. The study was focused on AA6082T6 aluminium thin sheets. In most dynamic sheet metal forming operations, the highly nonlinear deformation processes cause large amounts of elastic strain energy stored in the formed material. The novel hybrid forming process was thus aimed at inducing the local heating of the mechanically bent workpiece in order to decrease or eliminate the related springback phenomena. In particular, the influence on the extent of springback phenomena of laser process parameters such as source power, scan speed and starting elastic deformation of mechanically bent sheets, was experimentally assessed. Consistent trends in experimental response according to operational parameters were found. Accordingly, 3D process maps of the extent of the springback phenomena according to operational parameters were constructed. The effect of the inherent uncertainties on the predicted residual bending caused by the approximation in the model parameters was evaluated. In particular, a fuzzy-logic based approach was used to describe the model uncertainties and the transformation method was applied to propagate their effect on the residual bending.
Irradiation creep of stainless steel in bending
International Nuclear Information System (INIS)
The development is described of a test to measure irradiation enhanced creep in bending of 20% cold-worked Type-316 stainless steel. The test will be irradiated in the experimental fast reactor EBR-II. The rationale used in design selection is described. The selected beam designs, the supportive tests in other stress states and the measurement techniques are described in detail. (Auth.)
Irradiation creep of stainless steel in bending
International Nuclear Information System (INIS)
The development is described of a test to measure irradiation enhanced creep in bending of 20% cold-worked Type-316 stainless steel. The test will be irradiated in the experimental fast reactor EBR-II. The rationale used in design selection is described. The selected beam designs, the supportive tests in other stress states and the measurement techniques are described in detail
Bending of a thin flexible plate
Energy Technology Data Exchange (ETDEWEB)
Pobedria, B.E.
1990-12-01
A system of equations is derived which describes the one-dimensional deformation of thin shells. The analysis does not impose any constraints on the relative elongation and deflections. As an example, a solution is presented for the problem of the bending of a thin plate under uniform pressure.
Reconstruction of convex bodies from moments
DEFF Research Database (Denmark)
Hörrmann, Julia; Kousholt, Astrid
We investigate how much information about a convex body can be retrieved from a finite number of its geometric moments. We give a sufficient condition for a convex body to be uniquely determined by a finite number of its geometric moments, and we show that among all convex bodies, those which are...... uniquely determined by a finite number of moments form a dense set. Further, we derive a stability result for convex bodies based on geometric moments. It turns out that the stability result is improved considerably by using another set of moments, namely Legendre moments. We present a reconstruction algo......- rithm that approximates a convex body using a finite number of its Legendre moments. The consistency of the algorithm is established using the stabil- ity result for Legendre moments. When only noisy measurements of Legendre moments are available, the consistency of the algorithm is established under...
Linear and non-linear analyses for semi-elliptical surface cracks in pipes under bending
International Nuclear Information System (INIS)
In this paper, the J integral was calculated for semi-elliptical surface cracks in pipes under bending using three-dimensional finite element analysis. The computations were performed for elastic and elastic-plastic behaviours. For the elastic case, the numerical results allowed the extrapolation of shape functions for analytical determination of the J integral. The results are in a good agreement with those in the literature if the ratio between the radius and the thickness of the pipe (R/t) is from 1 to 10. The analysis was extended to values of the ratio R/t higher than 10. For the elastic-plastic, the numerical results are in good agreement with the analytical solution found in the literature for thick pipes (R/t ≥ 10). The effect of the ratio R/t becomes sensible when the ratio of the applied moment to the moment of reference (M/MoR) exceeds 0.9.
Linear and non-linear analyses for semi-elliptical surface cracks in pipes under bending
Energy Technology Data Exchange (ETDEWEB)
Mechab, B. [LMPM, Department of Mechanical Engineering, University of Sidi Bel Abbes, Sidi Bel Abbes 22000 (Algeria); Serier, B., E-mail: boualems@yahoo.f [LMPM, Department of Mechanical Engineering, University of Sidi Bel Abbes, Sidi Bel Abbes 22000 (Algeria); Bouiadjra, B. Bachir [LMPM, Department of Mechanical Engineering, University of Sidi Bel Abbes, Sidi Bel Abbes 22000 (Algeria); Department of Mechanical Engineering, College of Engineering, King Saud University, Riyadh (Saudi Arabia); Kaddouri, K. [LMPM, Department of Mechanical Engineering, University of Sidi Bel Abbes, Sidi Bel Abbes 22000 (Algeria); Feaugas, X. [Laboratoire d' Etude des Materiaux en Milieux Agressifs (L.E.M.M.A), La Rochelle University, LaRochelle (France)
2011-01-15
In this paper, the J integral was calculated for semi-elliptical surface cracks in pipes under bending using three-dimensional finite element analysis. The computations were performed for elastic and elastic-plastic behaviours. For the elastic case, the numerical results allowed the extrapolation of shape functions for analytical determination of the J integral. The results are in a good agreement with those in the literature if the ratio between the radius and the thickness of the pipe (R/t) is from 1 to 10. The analysis was extended to values of the ratio R/t higher than 10. For the elastic-plastic, the numerical results are in good agreement with the analytical solution found in the literature for thick pipes (R/t {>=} 10). The effect of the ratio R/t becomes sensible when the ratio of the applied moment to the moment of reference (M/MoR) exceeds 0.9.
2006-01-01
One of the first events reconstructed in the Muon Drift Tubes, the Hadron Calorimeter and elements of the Silicon Tracker (TK) at 3 Tesla. The atmosphere in the CMS control rooms was electric. Everbody was at the helm for the first full-scale testing of the experiment. This was a crunch moment for the entire collaboration. On Tuesday, 22 August the magnet attained almost its nominal power of 4 Tesla! At the same moment, in a tiny improvised control room, the physicists were keyed up to test the entire detector system for the first time. The first cosmic ray tracks appeared on their screens in the week of 15 August. The tests are set to continue for several weeks more until the first CMS components are lowered into their final positions in the cavern.
Minimal muon anomalous magnetic moment
Biggio, Carla
2014-01-01
We classify all possible one-particle (scalar and fermion) extensions of the Standard Model that can contribute to the anomalous magnetic moment of leptons. We review the cases already discussed in the literature and complete the picture by performing the calculation for a fermionic doublet with hypercharge -3/2. We conclude that, out of the listed possibilities, only two scalar leptoquarks and the pseudoscalar of a peculiar two-Higgs-doublet model could be the responsibles for the muon anomalous magnetic moment discrepancy. Were this the case, this particles could be seen in the next LHC run. To this aim, especially to test the leptoquark hypothesis, we suggest to look for final states with tops and muons.
Geometric moments for gait description
Toxqui-Quitl, C.; Morales-Batalla, V.; Padilla-Vivanco, A.; Camacho-Bello, C.
2013-09-01
The optical flow associated with a set of digital images of a moving individual is analyzed in order to extract a gait signature. For this, invariant Hu moments are obtained for image description. A Hu Moment History (HMH) is obtained from K frames to describe the gait signature of individuals in a video. The gait descriptors are subsequences of the HMH of variable width. Each subsequence is generated by means of genetic algorithms and used for classification in a neuronal network. The database for algorithm evaluation is MoBo, and the gait classification results are above 90% for the cases of slow and fast walking and 100% for the cases of walking with a ball and inclined walking. An optical processor is also implemented in order to obtain the descriptors of the human gait.
Moments with the edgewise appliance: incisor torque control.
Isaacson, R J; Lindauer, S J; Rubenstein, L K
1993-05-01
Traditional edgewise orthodontic mechanics are significantly limited in their ability to provide incisor torque control because of the limitations of bracket-to-bracket mechanics and the poorly defined reciprocal actions inherently produced. Attempts to address this issue clinically have been largely empirical. The science of mechanics dictates that all incisor torque control mechanisms must act through one of two basic principles: the moment of a couple or the moment of a force. The torquing arch is a modification of the traditional edgewise system and employs the moment of a couple to achieve incisor torque control and precise definition of reciprocal effects. The torquing arch force system includes a large moment to rotate incisors in a crown facial/root lingual direction, and concurrent equilibrium forces to extrude incisors and intrude molars. Alternatively, the base arch uses the moment of a force to also rotate incisors in a crown facial/root lingual direction. The base arch, however, includes a large moment to rotate molars in a crown distal/root mesial direction, and concurrent equilibrium forces to intrude incisors and extrude molars. Depending on how they are employed, torquing arches and base arches may also rotate molars in a faciolingual direction, enhance or diminish posterior anchorage, and increase or conserve arch perimeter. Contemporary quality orthodontic care requires an awareness and control of all of the forces created by orthodontic appliances. PMID:8480711
From aerosol microphysics to geophysics using the method of moments
International Nuclear Information System (INIS)
We describe new developments in the application of the Quadrature Method of Moments (QMOM). These include the first application of the QMOM in a 3-D chemical transformation and transport model on the sub-hemispheric scale. The QMOM simultaneously tracks an arbitrary (even) number of moments of a particle size distribution directly in space and time without the need for explicitly representing the distribution itself. The present implementation evolves the six lowest-order radial moments for each of several externally-mixed aerosol populations. From these moments we report modeled geographic distributions of several aerosol properties, including a shortwave radiative forcing obtained using the Multiple Isomomental Distribution Aerosol Surrogate (MIDAS) technique. These results demonstrate the capabilities of these moment-based techniques to simultaneously represent aerosol nucleation, condensation, coagulation, dry deposition, wet removal, cloud activation, and transport processes in a large-scale model, and to yield aerosol optical properties and radiative influence from the modeled aerosol moments. We report on recent extensions of the method for simulation of internal mixtures and generally-mixed aerosols, and on a bivariate extension of the QMOM for modeling simultaneous coagulation and sintering of particle populations
Modelling of current distribution in Nb3Sn multifilamentary strands subjected to bending
Miyoshi, Y.; Zhou, C.; van Lanen, E. P. A.; Dhallé, M. M. J.; Nijhuis, A.
2012-05-01
In Nb3Sn cable-in-conduit conductors (CICCs), strands follow complex trajectories that result in a periodic bending strain acting on the strands upon electromagnetic loading and thermal contraction. Such a periodic bending strain leads to degradation of the overall transport performance of a CICC. Aiming for a better understanding and quantitative correlation between strand degradation and CICC test results, a detailed strand model is essential in combination with accurate intra-strand resistance data, the spatial filament strain distribution, and the associated filament crack distribution. Our novel numerical strand model is a 3D network of resistors including superconducting filaments, normal matrix elements, and an outer stabilizing shell or inner core. Along the strand length, matrix elements have Ohmic resistance, there is a filament-to-matrix contact resistance (Rfm) between filaments and matrix elements, while superconducting filaments have a power-law voltage-current (VI) characteristic with critical current (Ic) and an n-value described by the ITER Nb3Sn strain scaling law based on measured strand data. The model simulates the VI characteristic in a periodic bending experiment and provides the associated spatial potential distribution. The VI characteristics representing the low- and high-resistivity limits (LRL and HRL) are identified for periodic and uniform axial bending. The voltage level for the current transfer regime depends on the strand internal resistivities, i.e. the filament-to-matrix contact and the matrix resistivity, the twist pitch and the bending wavelength. The simulation results show good agreement against Ic degradation, as experimentally measured by the TARSIS facility, versus the assessed peak bending strain. In addition we discuss different methods for determining the applied peak bending strain. The model provides a basis to find a practical relationship between a strand’s VI characteristic and the periodic bending strain, as well
Modelling of current distribution in Nb3Sn multifilamentary strands subjected to bending
International Nuclear Information System (INIS)
In Nb3Sn cable-in-conduit conductors (CICCs), strands follow complex trajectories that result in a periodic bending strain acting on the strands upon electromagnetic loading and thermal contraction. Such a periodic bending strain leads to degradation of the overall transport performance of a CICC. Aiming for a better understanding and quantitative correlation between strand degradation and CICC test results, a detailed strand model is essential in combination with accurate intra-strand resistance data, the spatial filament strain distribution, and the associated filament crack distribution. Our novel numerical strand model is a 3D network of resistors including superconducting filaments, normal matrix elements, and an outer stabilizing shell or inner core. Along the strand length, matrix elements have Ohmic resistance, there is a filament-to-matrix contact resistance (Rfm) between filaments and matrix elements, while superconducting filaments have a power-law voltage–current (VI) characteristic with critical current (Ic) and an n-value described by the ITER Nb3Sn strain scaling law based on measured strand data. The model simulates the VI characteristic in a periodic bending experiment and provides the associated spatial potential distribution. The VI characteristics representing the low- and high-resistivity limits (LRL and HRL) are identified for periodic and uniform axial bending. The voltage level for the current transfer regime depends on the strand internal resistivities, i.e. the filament-to-matrix contact and the matrix resistivity, the twist pitch and the bending wavelength. The simulation results show good agreement against Ic degradation, as experimentally measured by the TARSIS facility, versus the assessed peak bending strain. In addition we discuss different methods for determining the applied peak bending strain. The model provides a basis to find a practical relationship between a strand’s VI characteristic and the periodic bending strain, as
fMRI-compatible registration of jaw movements using a fiber-optic bend sensor
Directory of Open Access Journals (Sweden)
Bradley J MacIntosh
2010-03-01
Full Text Available A functional magnetic resonance imaging (fMRI-compatible fiber-optic bend sensor was investigated to assess whether the device could be used effectively to monitor opening and closing of the jaw during an fMRI experiment at 3 T. In contrast to surface electromyography, a bend sensor fixed to the chin of the participant is fast and easy to use and is not affected by strong electromagnetic fields. Bend sensor recordings are characterized by high validity (compared with concurrent video recordings of mouth opening and high reliability (comparing 2 independent measurements. The results of this study indicate that a bend sensor is able to record the opening and closing of the jaw associated with different overt speech conditions (producing the utterances /a/, /pa/, /pataka/ and the opening of the mouth without speech production. Data post-processing such as filtering was not necessary. There are several potential applications for bend sensor recordings of speech-related jaw movements. First, bend sensor recordings are a valuable tool to assess behavioral performance, such as response latencies, accuracies, and completion times, which is particularly important in children, seniors, or patients with various neurological or psychiatric conditions. Second, the timing information provided by bend sensor data may improve the predicted hemodynamic response that is used for fMRI analysis based on the general linear model (GLM. Third, bend sensor recordings may be included in GLM analyses not for statistical contrast purposes, but as a covariate of no interest, accounting for part of the data variance to model fMRI artifacts due to motion outside the field of view.
fMRI-Compatible Registration of Jaw Movements Using a Fiber-Optic Bend Sensor.
Sörös, Peter; Macintosh, Bradley J; Tam, Fred; Graham, Simon J
2010-01-01
A functional magnetic resonance imaging (fMRI)-compatible fiber-optic bend sensor was investigated to assess whether the device could be used effectively to monitor opening and closing of the jaw during an fMRI experiment at 3 T. In contrast to surface electromyography, a bend sensor fixed to the chin of the participant is fast and easy to use and is not affected by strong electromagnetic fields. Bend sensor recordings are characterized by high validity (compared with concurrent video recordings of mouth opening) and high reliability (comparing two independent measurements). The results of this study indicate that a bend sensor is able to record the opening and closing of the jaw associated with different overt speech conditions (producing the utterances /a/, /pa/, /pataka/) and the opening of the mouth without speech production. Data post-processing such as filtering was not necessary. There are several potential applications for bend sensor recordings of speech-related jaw movements. First, bend sensor recordings are a valuable tool to assess behavioral performance, such as response latencies, accuracies, and completion times, which is particularly important in children, seniors, or patients with various neurological or psychiatric conditions. Second, the timing information provided by bend sensor data may improve the predicted hemodynamic response that is used for fMRI analysis based on the general linear model (GLM). Third, bend sensor recordings may be included in GLM analyses not for statistical contrast purposes, but as a covariate of no interest, accounting for part of the data variance to model fMRI artifacts due to motion outside the field of view. PMID:20463865
Evaluation of the physical characteristic of Cerro bend blocks used for radiation therapy
International Nuclear Information System (INIS)
In Radiation Therapy, the sparing of normal tissues can be performed using either multi-leaf collimators or Cerro bend blocks. The current work focuses on the physical characteristics of Cerro bend blocks including attenuation coefficient, effective penumbra width and isodose curves undulation in penumbral regions. Materials and Methods: All measurements were performed using a dual energy linac and the Cerro bend blocks designed and fabricated using a commercial Cerro bend material. Data were collected using a calibrated ionization chamber as well as EDR2 films. Results: The results showed that the attenuation coefficient was found to be 0.4475 and 0.4276 cm-1 for photon beams 6 MV and 15 MV, respectively, and a potential air bubble with a diameter greater than 3 mm affects beam attenuation significantly. The optimum Cerro bend block width was found to be around 16 mm. The isodose curves scalloping achieved for secondary collimator jaws, were also similar. Conclusion: If Cerro bend blocks are used as a basic method to protect normal tissues, its physical characteristics will be recommended to be taken into account comprehensively.
Rotation, scaling, and translation invariant local watermarking technique with Krawtchouk moments
Institute of Scientific and Technical Information of China (English)
Li Zhang; Weiwei Xiao; Gongbin Qian; Zhen Ji
2007-01-01
A rotation, scaling, and translation invariant local watermarking is proposed with one or two Krawtchouk moment(s) of the original to estimate the geometric distortion parameters including rotation angle, scaling factor, and translation parameter. Krawtchouk moments can be used as private key of watermark extractor.Watermark is inserted into perceptually significant Krawtchouk moments of original, and watermark based on Krawtchouk moments is local. Independent component analysis (ICA) is utilized to extract watermark blindly. Experimental results show that this method has a good robustness against distortions preformed by watermark benchmark Stirmark.
When Blood Cells Bend: Understanding Sickle Cell Disease
... please review our exit disclaimer . Subscribe When Blood Cells Bend Understanding Sickle Cell Disease For people who don’t suspect they ... Cells Bend Wise Choices Links Living with Sickle Cell Disease See a sickle cell disease expert regularly. ...
Porsev, S G; Flambaum, V V
2010-01-01
We have considered a mechanism for inducing a time-reversal violating electric dipole moment (EDM) in atoms through the interaction of a nuclear EDM (d_N) with the hyperfine interaction, the "magnetic moment effect". We have derived the operator for this interaction and presented analytical formulas for the matrix elements between atomic states. Induced EDMs in the diamagnetic atoms 129Xe, 171Yb, 199Hg, 211Rn, and 225Ra have been calculated numerically. From the experimental limits on the atomic EDMs of 129Xe and 199Hg, we have placed the following constraints on the nuclear EDMs, |d_N(129Xe)|< 1.1 * 10^{-21} |e|cm and |d_N(199Hg)|< 2.8 * 10^{-24} |e|cm.
Quantitative Evaluation of Photoinduced Bending Speed of Diarylethene Crystals
Directory of Open Access Journals (Sweden)
Daichi Kitagawa
2015-11-01
Full Text Available We investigated photoinduced crystal bending behavior of various photochromic diarylethenes. In all the diarylethene derivatives we used in this work, the relationship between the initial photoinduced bending speed and the crystal thickness was well explained by the easy-handled Timoshenkoʼs bimetal model. Moreover, we proposed a quantitative analysis method to reveal the relationship between the bending speed and the molecular structure of diarylethenes. These results provide the quantitative evaluation method of the photoinduced crystal bending speed.
The design of an agent to bend DNA.
Akiyama, T; Hogan, M E
1996-01-01
An artificial DNA bending agent has been designed to assess helix flexibility over regions as small as a protein binding site. Bending was obtained by linking a pair of 15-base-long triple helix forming oligonucleotides (TFOs) by an adjustable polymeric linker. By design, DNA bending was introduced into the double helix within a 10-bp spacer region positioned between the two sites of 15-base triple helix formation. The existence of this bend has been confirmed by circular permutation and phas...
Wild Bootstrap Versus Moment-Oriented Bootstrap
Sommerfeld, Volker
1997-01-01
We investigate the relative merits of a “moment-oriented” bootstrap method of Bunke (1997) in comparison with the classical wild bootstrap of Wu (1986) in nonparametric heteroscedastic regression situations. The “moment-oriented” bootstrap is a wild bootstrap based on local estimators of higher order error moments that are smoothed by kernel smoothers. In this paper we perform an asymptotic comparison of these two dierent bootstrap procedures. We show that the moment-oriented bootstrap is in ...
Ultrasonic fatigue testing device under biaxial bending
Directory of Open Access Journals (Sweden)
C. Brugger
2016-07-01
Full Text Available A new fatigue testing device has been developed to test specimens under biaxial loading at 20 kHz. A flat smooth specimen with a disc geometry is placed on a torus frame and cyclically loaded at the center of its upper face. Disc bending generates a biaxial proportional stress state at the center of the lower face. Any positive loading ratio can be applied. A cast aluminum alloy (used to produce cylinder heads has been tested under biaxial bending using this device in order to determine its fatigue strength at 109 cycles under high hydrostatic pressure. Self-heating is moderate but macroscopic fatigue cracks after testing are very long. First results in VHCF regime are consistent with literature results obtained under similar stress state but in HCF regime and at 20 Hz.
Development of Bend Sensor for Catheter Tip
Nagano, Yoshitaka; Sano, Akihito; Fujimoto, Hideo
Recently, a minimally invasive surgery which makes the best use of the catheter has been becoming more popular. In endovascular coil embolization for a cerebral aneurysm, the observation of the catheter's painting phenomenon is very important to execute the appropriate manipulation of the delivery wire and the catheter. In this study, the internal bend sensor which consists of at least two bending enhanced plastic optical fibers was developed in order to measure the curvature of the catheter tip. Consequently, the painting could be more sensitively detected in the neighborhood of the aneurysm. In this paper, the basic characteristics of the developed sensor system are described and its usefulness is confirmed from the comparison of the insertion force of delivery wire and the curvature of catheter tip in the experiment of coil embolization.
Monitoring thermoplastic composites under cyclic bending tests
Boccardi, Simone; Meola, Carosena; Carlomagno, Giovanni Maria; Simeoli, Giorgio; Acierno, Domenico; Russo, Pietro
2016-05-01
This work is concerned with the use of infrared thermography to visualize temperature variations linked to thermo-elastic effects developing over the surface of a specimen undergoing deflection under bending tests. Several specimens are herein considered, which involve change of matrix and/or reinforcement. More specifically, the matrix is either a pure polypropylene, or a polypropylene added with a certain percentage of compatibilizing agent; the reinforcement is made of glass, or jute. Cyclic bending tests are carried out by the aid of an electromechanical actuator. Each specimen is viewed, during deflection, from one surface by an infrared imaging device. As main finding the different specimens display surface temperature variations which depend on the type of material in terms of both matrix and reinforcement.
Molecular Origin of Model Membrane Bending Rigidity
International Nuclear Information System (INIS)
The behavior of the bending modulus κ of bilayers in lamellar phases was studied by Small Angle X-ray Scattering technique for various nonionic CiEj surfactants. The bilayers are either unswollen and dispersed in water or swollen by water and dispersed in dodecane. For unswollen bilayers, the values of κ decrease with both an increase in the area per surfactant molecule and in the polar head length. They increase when the aliphatic chain length increases at constant area per surfactant molecule. Whereas for water-swollen membranes, the values of κ decrease as the content of water increases converging to the value of the single monolayer bending modulus. Such a behavior results from the decoupling of the fluctuations of the two surfactant membrane monolayers. Our results emphasize the determinant contribution of the surfactant conformation to κ
Molecular Origin of Model Membrane Bending Rigidity
Kurtisovski, Erol; Taulier, Nicolas; Ober, Raymond; Waks, Marcel; Urbach, Wladimir
2007-06-01
The behavior of the bending modulus κ of bilayers in lamellar phases was studied by Small Angle X-ray Scattering technique for various nonionic CiEj surfactants. The bilayers are either unswollen and dispersed in water or swollen by water and dispersed in dodecane. For unswollen bilayers, the values of κ decrease with both an increase in the area per surfactant molecule and in the polar head length. They increase when the aliphatic chain length increases at constant area per surfactant molecule. Whereas for water-swollen membranes, the values of κ decrease as the content of water increases converging to the value of the single monolayer bending modulus. Such a behavior results from the decoupling of the fluctuations of the two surfactant membrane monolayers. Our results emphasize the determinant contribution of the surfactant conformation to κ
Characterization and study of photonic crystal fibres with bends
International Nuclear Information System (INIS)
Analysis of a photonic crystal fibre (PRCF) with bends is presented. Using the versatile finite difference time domain method, the modal characteristics of the PCFs are found. Possibilities of employing PCFs with bends in sensing are discussed. It is found that a large evanescent field is present when the bend angle exceeds 45o
Defining moments in leadership character development.
Bleich, Michael R
2015-06-01
Critical moments in life define one's character and clarify true values. Reflective leadership is espoused as an important practice for transformational leaders. Professional development educators can help surface and explore defining moments, strengthen leadership behavior with defining moments as a catalyst for change, and create safe spaces for leaders to expand their leadership capacity. PMID:26057159
The Krein condition for the moment problem
DEFF Research Database (Denmark)
Pedersen, Henrik Laurberg
2005-01-01
In this paper, we describe a class of Wiener functionals that are `indeterminate by their moments', that is, whose distributions are not uniquely determined by their moments. In particular, it is proved that the integral of a geometric Brownian motion is indeterminate by its moments and, moreover...
Superconducting beam bending magnets at CERN
1977-01-01
The photo shows Gerhard Kesseler with the cyogenic vessels for one of the 10.8 Tesla-metre beam bending magnets. The magnet itself (not visible) is sitting inside the superinsukated helium vessel (white). The next larger shell and the biggest tubular structure (with the largest part behind the person) is the insulation vacuum tank. See CERN Courier 1970 pp. 228-229 CERN Courier 1973 pp. 144-145 Yellow Report CERN 78-03, 1978
AA, assembly of wide bending magnet
1980-01-01
The very particular lattice of the AA required 2 types of dipoles (bending magnets; BST, short and wide; BLG, long and narrow). The wide ones had a steel length of 2.71 m, a "good field" width of 0.564 m, and a weight of about 75 t. Here we see the copper coils being hoisted onto the lower half of a BST. See also 7811105, 8006050. For a BLG, see 8001044.
Large deformation dynamic bending of composite beams
Derian, Edward J.
1985-01-01
The large deformation response of composite beams subjected to a dynamic axial load was studied. The beams were loaded with a moderate amount of eccentricity to promote bending. The study was primarily experimental but some finite element results were obtained. Both the deformation and the failure of the beams were of interest. The static response of the beams was also studied in order to determine the difference between the static and dynamic failure. Twelve different la...
Drag Reduction, from Bending to Pruning
Lopez, Diego; Michelin, Sébastien; de Langre, Emmanuel
2013-01-01
Most plants and benthic organisms have evolved efficient reconfiguration mechanisms to resist flow-induced loads. These mechanisms can be divided into bending, in which plants reduce their sail area through elastic deformation, and pruning, in which the loads are decreased through partial breakage of the structure. In this work, we show by using idealized models that these two mechanisms or, in fact, any combination of the two, are equally efficient to reduce the drag experienced by terrestrial and aquatic vegetation.
More on the bending of light !
Lake, Kayll
2007-01-01
Recently, Rindler and Ishak have argued that the bending of light is, in principle, changed by the presence of a cosmological constant since one must consider not only the null geodesic equation, but also the process of measurement. I agree with the fact that both must be considered. Here, on the basis of the mathematically exact solution to the classical bending problem, and independent of the cosmological constant, I show that the approximate argument found in the vast majority of texts (new and old) for the measured value of the bending of light for a single source is, despite getting a good answer, bogus. In fact, the measured value for a single source is in part the result of the almost perfect cancelation of two terms, one of which is seldom considered. When one considers two sources, this cancelation is of no consequence, and if the sources are opposite with the same associated apsidal distance, the approximate argument gives the rigorously correct answer (up to numerical evaluation), an answer which i...
First multi-bend achromat lattice consideration
International Nuclear Information System (INIS)
The first proposed lattice for a ‘diffraction-limited light source’ is reported. This approach has now more or less been used for the MAX IV project. By the beginning of 1990, three third-generation synchrotron light sources had been successfully commissioned in Grenoble, Berkeley and Trieste (ESRF, ALS and ELETTRA). Each of these new machines reached their target specifications without any significant problems. In parallel, already at that time discussions were underway regarding the next generation, the ‘diffraction-limited light source (DLSR)’, which featured sub-nm rad electron beam emittance, photon beam brilliance exceeding 1022 and the potential to emit coherent radiation. Also, at about that time, a first design for a 3 GeV DLSR was developed, based on a modified multiple-bend achromat (MBA) design leading to a lattice with normalized emittance of ∊x = 0.5 nm rad. The novel feature of the MBA lattice was the use of seven vertically focusing bend magnets with different bending angles throughout the achromat cell to keep the radiation integrals and resulting beam emittance low. The baseline design called for a 400 m ring circumference with 12 straight sections of 6 m length. The dynamic aperture behaviour of the DLSR lattice was estimated to produce > 5 h beam lifetime at 100 mA stored beam current
The role of elasticity in slab bending
Fourel, Loic; Goes, Saskia; Morra, Gabriele
2014-11-01
studies showed that plate rheology exerts a dominant control on the shape and velocity of subducting plates. Here, we perform a systematic investigation of the role of elasticity in slab bending, using fully dynamic 2-D models where an elastic, viscoelastic, or viscoelastoplastic plate subducts freely into a purely viscous mantle. We derive a scaling relationship between the bending radius of viscoelastic slabs and the Deborah number, De, which is the ratio of Maxwell time over deformation time. We show that De controls the ratio of elastically stored energy over viscously dissipated energy and find that at De>10-2, substantially less energy is required to bend a viscoelastic slab to the same shape as a purely viscous slab with the same intrinsic viscosity. Elastically stored energy at higher De favors retreating modes of subduction via unbending, while trench advance only occurs for some cases with De 1, where most zones have low De 0.1. Slabs with Deviscosities or they may be yielding, in which case our De estimates may be underestimated by up to an order of magnitude, potentially pointing towards a significant role of elasticity in ˜60% of the subduction zones. In support of such a role of elasticity in subduction, we find that increasing De correlates with increasing proportion of larger seismic events in both instrumental and historic catalogues.
Spore and the sociocultural moment
Meyer, W. Max
2012-12-01
Analyses of the game Spore have centered on the important issues of accuracy of evolution content and engendering interest in science. This paper suggests that examination of the degree of scaffolding necessary to use the game in pedagogy is a missing part of the discussion, and then questions the longevity of the Spore discussion relative to the general dissatisfaction with the science presented in the game. The paper proposes that analysis of Spore and other technological tools in science education may be embedded in an historical moment which directs the discussion towards satisfying sociocultural and organizational needs and away from pedagogical ones.
Factorial moments of continuous order
International Nuclear Information System (INIS)
The normalized factorial moments Fq are continued to noninteger values of the order q, satisfying the condition that the statistical fluctuations remain filtered out. That is, for the Poisson distribution Fq=1 for all q. The continuation procedure is deisgned with phenomenology and data analysis in mind. Examples are given to show how Fq can be obtained for positive and negative values of q. With q being continuous, a multifractal analysis is made possible for multiplicity distributions that arise from self-similar dynamics. A step-by-step procedure of the method is summarized in the conclusion
Electromagnetic dipole moments of fermions
Fael, Matteo
2014-01-01
The electric (EDM) and magnetic (g-2) dipole moments are static properties sensitive to quantum corrections induced by the virtual particles that populate the vacuum. Indeed, they are well suited to test the Standard Model of Elementary of particle physics and to unveil unknown New Physics (NP) hidden at high energy. The electron and muon g-2 have been measured with the wonderful precision of 0.24 ppb and 0.54 ppm, respectively, and thus they represent one of the strongest confirmation ...
Electric and Magnetic Dipole Moments
CERN. Geneva
2005-01-01
The stringent limit on the electric dipole moment of the neutron forced the issue on the strong CP-problem. The most elegant solution of which is the axion field proposed by Peccei and Quinn. The current limit on the QCD parameter theta coming from the limit on the neutron EDM is of order 10-10. I am going to describe the present status on the neutron EDM searches and further prospects on getting down to theta_qcd sensitivity of 10-13 with the new deuteron EDM in storage rings proposal. For completeness the current status and prospects of the muon g-2 experiment will also be given.
In vivo assessment of forearm bone mass and ulnar bending stiffness in healthy men
Myburgh, K. H.; Zhou, L. J.; Steele, C. R.; Arnaud, S.; Marcus, R.
1992-01-01
The cross-sectional bending stiffness EI of the ulna was measured in vivo by mechanical resistance tissue analysis (MRTA) in 90 men aged 19-89 years. MRTA measures the impedance response of low-frequency vibrations to determine EI, which is a reflection of elastic modulus E and moment of inertia I for the whole ulna. EI was compared to conventional estimates of bone mineral content (BMC), bone width (BW), and BMC/BW, which were all measured by single-photon absorptiometry. Results obtained from the nondominant ulna indicate that BW increases (r = 0.27, p = 0.01) and ulnar BMC/BW decreases (r = -0.31, p < or = 0.005) with age. Neither BMC nor EI declined with age. The single best predictor of EI was BW (r2 = 0.47, p = 0.0001), and further small but significant contributions were made by BMC (r2 = 0.53, p = 0.0001) and grip strength (r2 = 0.55, p = 0.0001). These results suggest that the resistance of older men to forearm fracture is related to age-associated changes in the moment of inertia achieved by redistributing bone mineral farther from the bending axis. We conclude that the in vivo assessment of bone geometry offers important insights to the comprehensive evaluation of bone strength.
Layer model for long-term deflection analysis of cracked reinforced concrete bending members
Bacinskas, Darius; Kaklauskas, Gintaris; Gribniak, Viktor; Sung, Wen-Pei; Shih, Ming-Hsiang
2012-05-01
A numerical technique has been proposed for the long-term deformation analysis of reinforced concrete members subjected to a bending moment. The technique based on the layer approach in a simple and rational way deals with such complex issues as concrete cracking and tension-stiffening as well as creep and shrinkage. The approach uses the material stress-strain relationships for compressive concrete, cracked tensile concrete and steel. Such effects as linear and nonlinear creep, cracking, tension-stiffening as well as the reduction in concrete tension strength due to sustained loading have been taken into account. The shrinkage effect has been modeled by means of adequate actions of axial force and bending moment. A statistical deflection calculation analysis has been carried out for 322 experimental reinforced concrete beams reported in the literature. The comparative analysis of the experimental and the modeling results has shown that the proposed technique has well captured the time-deflection behavior of reinforced concrete flexural members. The results of the predictions by ACI 318 and Eurocode 2 design codes have been also discussed.
2010-11-24
... Jeffries, District Ranger, Bend-Fort Rock Ranger District, Red Oaks Square, 1230 NE. Third Street, Suite A...-Fort Rock Ranger District, Red Oaks Square, 1230 NE. Third Street, Suite A-262, Bend, Oregon 97701... Forest Service Bend/Ft. Rock Ranger District; Deschutes National Forest; Deschutes County, OR; West...
2013-01-22
... COMMISSION PPL Bell Bend, LLC; Combined License Application for Bell Bend Nuclear Power Plant; Exemption 1.0... Approvals for Nuclear Power Plants.'' This reactor is to be identified as Bell Bend Nuclear Power Plant... (RCOL) application for UniStar's Calvert Cliffs Nuclear Power Plant, Unit 3 (CCNPP3). The NRC...
2011-12-29
... COMMISSION PPL Bell Bend, LLC; Combined License Application for Bell Bend Nuclear Power Plant; Exemption 1.0..., Certifications, and Approvals for Nuclear Power Plants.'' This reactor is to be identified as Bell Bend Nuclear... application is based upon the U.S. EPR reference COL (RCOL) application for UniStar's Calvert Cliffs...
Perception and Haptic Rendering of Friction Moments.
Kawasaki, H; Ohtuka, Y; Koide, S; Mouri, T
2011-01-01
This paper considers moments due to friction forces on the human fingertip. A computational technique called the friction moment arc method is presented. The method computes the static and/or dynamic friction moment independent of a friction force calculation. In addition, a new finger holder to display friction moment is presented. This device incorporates a small brushless motor and disk, and connects the human's finger to an interface finger of the five-fingered haptic interface robot HIRO II. Subjects' perception of friction moment while wearing the finger holder, as well as perceptions during object manipulation in a virtual reality environment, were evaluated experimentally. PMID:26962953
On the photon anomalous magnetic moment
Villalba, S; Villalba, Selym; Rojas, Hugo Perez
2006-01-01
It is shown that due to radiative corrections a photon having a non vanishing component of its momentum perpendicular to it, bears a non-zero magnetic moment. All modes of propagation of the polarization operator in one loop approximation are discussed and in this field regime the dispersion equation and the corresponding magnetic moment are derived. Near the first thresholds of cyclotron resonance the photon magnetic moment has a peak larger than the electron anomalous magnetic moment. Related to this magnetic moment, the arising of some sort of photon "dynamical mass" and a gyromagnetic ratio are discussed. These latter results might be interesting in an astrophysical context.
Tunable waveguide bends with graphene-based anisotropic metamaterials
Chen, Zhao-xian
2016-01-15
We design tunable waveguide bends filled with graphene-based anisotropic metamaterials to achieve a nearly perfect bending effect. The anisotropic properties of the metamaterials can be described by the effective medium theory. The nearly perfect bending effect is demonstrated by finite element simulations of various structures with different bending curvatures and shapes. This effect is attributed to zero effective permittivity along the direction of propagation and matched effective impedance at the interfaces between the bending part and the dielectric waveguides. We envisage that the design will be applicable in the far-infrared and terahertz frequency ranges owing to the tunable dielectric responses of graphene.
Moment determinants as isomonodromic tau functions
International Nuclear Information System (INIS)
We consider a wide class of determinants whose entries are moments of the so-called semiclassical functionals and we show that they are tau functions for an appropriate isomonodromic family which depends on the parameters of the symbols for the functionals. This shows that the vanishing of the tau function for those systems is the obstruction to the solvability of a Riemann–Hilbert problem associated with certain classes of (multiple) orthogonal polynomials. The determinants include Hankel, Toeplitz and shifted-Toeplitz determinants as well as determinants of bimoment functionals and the determinants arising in the study of multiple orthogonality. Some of these determinants also appear as partition functions of random matrix models, including an instance of a two-matrix model
A uniform parametrization of moment tensors
Tape, Walter; Tape, Carl
2015-09-01
A moment tensor is a 3 × 3 symmetric matrix that expresses an earthquake source. We construct a parametrization of the 5-D space of all moment tensors of unit norm. The coordinates associated with the parametrization are closely related to moment tensor orientations and source types. The parametrization is uniform, in the sense that equal volumes in the coordinate domain of the parametrization correspond to equal volumes of moment tensors. Uniformly distributed points in the coordinate domain therefore give uniformly distributed moment tensors. A cartesian grid in the coordinate domain can be used to search efficiently over moment tensors. We find that uniformly distributed moment tensors have uniformly distributed orientations (eigenframes), but that their source types (eigenvalue triples) are distributed so as to favour double couples.
On the Spectral Moments of Wind Waves
Institute of Scientific and Technical Information of China (English)
李陆平; 黄培基
2002-01-01
In order to obtain high order spectral moments, the residual moment M( ωn )i ＝∫ωn0ωiS(ω)dω, as proposed by Dehis, is presented for approximate estimation of spectral moment mi ＝∫m0ωiS(ω)dω. Glazman's partial averaging idea isdiscussed. It is pointed out that Glazman's method and definition of non-dimensional spectral moment can not be used to es-timate spectral moments for engineering purposes and that method is not supported by theory and computation. The non-di-mensional spectral moment of PM spectnun, which should be expressed as Mi = M(ωn ) i/ag2ω0i-p+1 , is related to wind speed. The0～ 8th moments of PM spectrum are estimated for wind speeds of 10, 20 and 30 m/s and some discussions are given.
Analysis of pipe mitred bends using beam models - by finite element method
International Nuclear Information System (INIS)
The formulation of a recently proposed displacement based straight pipe element for the analysis of pipe mitred bends is summarized in this work. The element kinematics includes axial, bending, torsional and ovalisation displacements, all varying cubically along the axis of the element. Interaction effects between angle adjoined straight pipe section are modeled including the appropriate additional strain terms in the stiffness matrix formulation and by using a penalty procedure to enforce continuity of pipe skin flexural rotations at the common helical edge. The element model capabilities are ilustrated in some sample analysis and the results are compared with other available experimental, analytical or more complex numerical models. (Author)
Feature-guided waves (FGW) in plate structures with 90° transverse bends
Yu, Xudong; Manogharan, Prabhakaran; Fan, Zheng; Rajagopal, Prabhu
2015-03-01
Ultrasonic guided waves are attractive for rapid remote screening of large structures and today they are widely used in several practical applications including the inspection of pipe and plate installations. More recently, guided wave modal solutions confined in extended local features have attracted much research interest, offering the possibility of inspecting complex geometric or topographical features. Such feature-guided wave (FGW) modes have been reported in plate waveguides with local cross-section variation or curvature, and in annular circular cylinders with cross-sectional anomalies. This paper focuses on FGW phenomena in 90 degree structural bends in plate structures, which commonly occur in various industrial structures. Modal studies are carried out using the Semi-Analytical Finite Element (SAFE) method, while 3D finite element (FE) simulations are used to gain visualization of results and also obtain cross-validation. Our studies reveal, perhaps for the first time, the possibility of bend-guided modes of the shear-horizontal (SH) family, in addition those of the Rayleigh-Lamb family reported earlier in the literature. This mode has attractive properties including low attenuation and limited dispersion. We investigate effects of plate thickness and bend radius on the physics of FGW in bends, arguing the strong role of geometry and curvature effects in causing mode confinement. Preliminary experiments have also been carried out to validate the existence of such bend-guided mode.
Evolving efficiency of restraining bends within wet kaolin analog experiments
Hatem, Alexandra E.; Cooke, Michele L.; Madden, Elizabeth H.
2015-03-01
Restraining bends along strike-slip fault systems evolve by both propagation of new faults and abandonment of fault segments. Scaled analog modeling using wet kaolin allows for qualitative and quantitative observations of this evolution. To explore how bend geometry affects evolution, we model bends with a variety of initial angles, θ, from θ = 0° for a straight fault to θ = 30°. High-angle restraining bends (θ ≥ 20°) overcome initial inefficiencies by abandoning unfavorably oriented restraining segments and propagating multiple new, inwardly dipping, oblique-slip faults that are well oriented to accommodate convergence within the bend. Restraining bends with 0° < θ ≤ 15° maintain activity along the restraining bend segment and grow a single new oblique slip fault on one side of the bend. In all restraining bends, the first new fault propagates at ~5 mm of accumulated convergence. Particle Image Velocimetry analysis provides a complete velocity field throughout the experiments. From these data, we quantify the strike-slip efficiency of the system as the percentage of applied plate-parallel velocity accommodated as slip in the direction of plate motion along faults within the restraining bend. Bends with small θ initially have higher strike-slip efficiency compared to bends with large θ. Although they have different fault geometries, all systems with a 5 cm bend width reach a steady strike-slip efficiency of 80% after 50 mm of applied plate displacement. These experimental restraining bends resemble crustal faults in their asymmetric fault growth, asymmetric topographic gradient, and strike-slip efficiency.
Cricket antennae shorten when bending (Acheta domesticus L.
Directory of Open Access Journals (Sweden)
CatherineLoudon
2014-06-01
Full Text Available Insect antennae are important mechanosensory and chemosensory organs. Insect appendages, such as antennae, are encased in a cuticular exoskeleton and are thought to bend only between segments or subsegments where the cuticle is thinner, more flexible, or bent into a fold. There is a growing appreciation of the dominating influence of folds in the mechanical behavior of a structure, and the bending of cricket antennae was considered in this context. Antennae will bend or deflect in response to forces, and the resulting bending behavior will affect the sensory input of the antennae. In some cricket antennae, such as in those of Acheta domesticus, there are a large number (>100 of subsegments (flagellomeres that vary in their length. We evaluated whether these antennae bend only at the joints between flagellomeres, which has always been assumed but not tested. In addition we questioned whether an antenna undergoes a length change as it bends, which would result from some patterns of joint deformation. Measurements using light microscopy and SEM were conducted on both male and female adult crickets (Acheta domesticus with bending in four different directions: dorsal, ventral, medial and lateral. Bending occurred only at the joints between flagellomeres, and antennae shortened a comparable amount during bending, regardless of sex or bending direction. The cuticular folds separating antennal flagellomeres are not very deep, and therefore as an antenna bends, the convex side (in tension does not have a lot of slack cuticle to "unfold" and does not lengthen during bending. Simultaneously on the other side of the antenna, on the concave side in compression, there is an increasing overlap in the folded cuticle of the joints during bending. Antennal shortening during bending would prevent stretching of antennal nerves and may promote hemolymph exchange between the antenna and head.
International Nuclear Information System (INIS)
Thin-walled tube bending is an advanced technology for producing precision bent tube parts in aerospace, aviation and automobiles, etc. With increasing demands of bending tubes with a larger tube diameter and a smaller bending radius, wrinkling instability is a critical issue to be solved urgently for improving the bending limit and forming quality in this process. In this study, by using the energy principle, combined with analytical and finite element (FE) numerical methods, an energy-based wrinkling prediction model for thin-walled tube bending is developed. A segment shell model is proposed to consider the critical wrinkling region, which captures the deformation features of the tube bending process. The dissipation energy created by the reaction forces at the tube–dies interface for restraining the compressive instability is also included in the prediction model, which can be numerically calculated via FE simulation. The validation of the model is performed and its physical significance is evaluated from various aspects. Then the plastic wrinkling behaviors in thin-walled tube bending are addressed. From the energy viewpoint, the effect of the basic parameters including the geometrical and material parameters on the onset of wrinkling is identified. In particular, the influence of multi-tools constraints such as clearance and friction at various interfaces on the wrinkling instability is obtained. The study provides instructive understanding of the plastic wrinkling instability and the model may be suitable for the wrinkling prediction of a doubly-curved shell in the complex forming process with contact conditions
Li, H; Yang, H; Zhan, M
2009-04-01
Thin-walled tube bending is an advanced technology for producing precision bent tube parts in aerospace, aviation and automobiles, etc. With increasing demands of bending tubes with a larger tube diameter and a smaller bending radius, wrinkling instability is a critical issue to be solved urgently for improving the bending limit and forming quality in this process. In this study, by using the energy principle, combined with analytical and finite element (FE) numerical methods, an energy-based wrinkling prediction model for thin-walled tube bending is developed. A segment shell model is proposed to consider the critical wrinkling region, which captures the deformation features of the tube bending process. The dissipation energy created by the reaction forces at the tube-dies interface for restraining the compressive instability is also included in the prediction model, which can be numerically calculated via FE simulation. The validation of the model is performed and its physical significance is evaluated from various aspects. Then the plastic wrinkling behaviors in thin-walled tube bending are addressed. From the energy viewpoint, the effect of the basic parameters including the geometrical and material parameters on the onset of wrinkling is identified. In particular, the influence of multi-tools constraints such as clearance and friction at various interfaces on the wrinkling instability is obtained. The study provides instructive understanding of the plastic wrinkling instability and the model may be suitable for the wrinkling prediction of a doubly-curved shell in the complex forming process with contact conditions.
Performance of composite I-beams under axial compression and bending load modes
Energy Technology Data Exchange (ETDEWEB)
Khalid, Y.A.; Ali, F.A.; Sahari, B.B.; Saad, E.M.A
2005-04-15
An experimental and finite-element analyses for glass/epoxy composite I-beams have been carried out. Four, six, eight and 10 layers of woven fabric glass/epoxy composite I-beams were fabricated by a hand lay-up (molding) process. Quasi-static axial crushing and bending loading modes were used for this investigation. The load-displacement response was obtained and the energy absorption values were calculated for all the composite I-beams. Three tests were done for each composite I-beams type and each loading case for the results conformation. The second part of this study includes the elastic behavior of composite I-beams of the same dimensions and materials using finite-element analysis. The woven fabric glass/epoxy composite I-beams mechanical properties have been obtained from tensile tests. Results from this investigation show that the load required and the specific energy absorption for composite I-beams under axial compression load were higher than those for three and four point bending. On the other hand, the loads required for composite I-beams under four point bending were higher than those for three point bending, while the specific energy absorption for composite I-beams under three point bending were higher than those for four point bending. The first crushing loads difference between the experimental and finite-element results fell in the 3.6-10.92% range for axial compression tests, while fell in the 1.44-12.99% and 4.94-22.0% range for three and four point bending, respectively.
Self-bending symmetric cusp beams
Gong, Lei; Liu, Wei-Wei; Ren, Yu-Xuan; Lu, Yao; Li, Yin-Mei
2015-12-01
A type of self-bending symmetric cusp beams with four accelerating intensity maxima is theoretically and experimentally presented. Distinguished from the reported regular polygon beams, the symmetric cusp beams simultaneously exhibit peculiar features of natural autofocusing and self-acceleration during propagation. Further, such beams take the shape of a fine longitudinal needle-like structure at the focal region and possess the strong ability of self-healing over obstacles. All these intriguing properties were verified experimentally. Particularly, the spatial profile of the reconstructed beam exhibits spatially sculpted optical structure with four siamesed curved arms. Thus, we anticipate that the structured beam will benefit optical guiding and optofluidics in surprising ways.
Self-bending symmetric cusp beams
Energy Technology Data Exchange (ETDEWEB)
Gong, Lei; Liu, Wei-Wei; Lu, Yao; Li, Yin-Mei, E-mail: liyinmei@ustc.edu.cn [Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei, Anhui Province 230026 (China); Ren, Yu-Xuan [Department of Physics and Astronomy, San Francisco State University, San Francisco, California 94132 (United States)
2015-12-07
A type of self-bending symmetric cusp beams with four accelerating intensity maxima is theoretically and experimentally presented. Distinguished from the reported regular polygon beams, the symmetric cusp beams simultaneously exhibit peculiar features of natural autofocusing and self-acceleration during propagation. Further, such beams take the shape of a fine longitudinal needle-like structure at the focal region and possess the strong ability of self-healing over obstacles. All these intriguing properties were verified experimentally. Particularly, the spatial profile of the reconstructed beam exhibits spatially sculpted optical structure with four siamesed curved arms. Thus, we anticipate that the structured beam will benefit optical guiding and optofluidics in surprising ways.
Bending of X65 Offshore Steel Pipes
Lofthaug, Kristoffer; Digerud, Erik
2014-01-01
This thesis is part of an ongoing research program between SIMLab and Statoil about impact loads on X65 offshore pipelines and it is a continuation of previous work.Offshore pipelines are frequently impacted by accidental loads, e.g. trawl gear or anchors. Such loads may cause severe damage to the pipe and a complex stress-strain history locally in the impacted area.Fracture have previously been found in pipes dynamically impacted. Quasi-static bending of similar pipes with the same boundary ...
Great Bend tornadoes of August 30, 1974
Umenhofer, T. A.; Fujita, T. T.; Dundas, R.
1977-01-01
Photogrammetric analyses of movies and still pictures taken of the Great Bend, Kansas Tornado series have been used to develop design specifications for nuclear power plants and facilities. A maximum tangential velocity of 57 m/sec and a maximum vertical velocity of 27 m/sec are determined for one suction vortex having a translational velocity of 32 m/sec. Three suction vortices with radii in the 20 to 30 m range are noted in the flow field of one tornado; these suction vortices apparently form a local convergence of inflow air inside the outer portion of the tornado core.
Bending moduli of polymeric surfactant interfaces
Milner, S.T.; Witten, T. A.
1988-01-01
Our recent theory of the free energy and conformations of end-grafted polymer « brushes » is extended to polymers attached to curved surfaces. Several important systems, e.g., layers of polymeric surfactants or of strongly segregated diblock copolymers, can be well described as brushes. By expanding in powers of the curvature the free energy of a brush on a curved surface, the mean and Gaussian bending moduli may be obtained analytically. Results for K and K of monodisperse brushes are consis...
Storm, C; Storm, Cornelis; Nelson, Philip
2002-01-01
We formulate and solve a two-state model for the elasticity of nicked, double-stranded DNA that borrows features from both the Worm Like Chain and the Bragg--Zimm model. Our model is computationally simple, and gives an excellent fit to recent experimental data through the entire overstretching transition. The fit gives the first value for the bending stiffness of the overstretched state as about 10 nm*kbt, a value quite different from either B-form or single-stranded DNA.
Extension versus Bending for Continuum Robots
Directory of Open Access Journals (Sweden)
George Grimes
2008-11-01
Full Text Available In this paper, we analyze the capabilities of a novel class of continuous-backbone ("continuum" robots. These robots are inspired by biological "trunks, and tentacles". However, the capabilities of established continuum robot designs, which feature controlled bending but not extension, fall short of those of their biological counterparts. In this paper, we argue that the addition of controlled extension provides dual and complementary functionality, and correspondingly enhanced performance, in continuum robots. We present an interval-based analysis to show how the inclusion of controllable extension significantly enhances the workspace and capabilities of continuum robots.
Wooden Model of Wide AA Bending Magnet
1978-01-01
The very particular lattice of the AA required 2 types of dipoles (bending magnets: BLG, long and narrow; BST, short and wide). A wide one had a steel length of 2.71 m, a "good field" width of 0.564 m, and a weight of about 75 t. A wooden model was build in 1978, to gain dimensional experience. Here, Peter Zettwoch, one of the largest men at CERN at that time, is putting a hand in the mouth of the wooden BST monster.
Institute of Scientific and Technical Information of China (English)
Odishelidze; N; Criado-Aldeanueva; F
2010-01-01
This paper addresses the problem of plate bending for a doubly connected body with outer and inner boundaries in the form of regular polygons with a common center and parallel sides.The neighborhoods of the vertices of the inner boundary are equal full-strength smooth arcs symmetric about the rays coming from the vertices to the center,but have unknown positions.Rigid bars are attached to the linear parts of the boundary.The plate bends by the moments applied to the middle point bars.The unknown arcs are free from external stresses.The same problem of plate bending is considered for a regular hexagon weakened by a full-strength hole.Using the methods of complex analysis,the analytical image of Kolosov-Muskhelishvili’s complex potentials (characterizing an elastic equilibrium of the body),the plate deflection and unknown parts of its boundary are determined under the condition that the tangential normal moment on that plate takes a constant value.Numerical analyses are also performed and the corresponding graphs are constructed.
Simulation of dilute pneumatic conveying with different types of bends by CFD-DEM
International Nuclear Information System (INIS)
Bends are one of the most commonly used facilities to change flow direction in pneumatic conveying. It is important to understand the effect of the bend to the gas-solid flow structures in a pneumatic conveying system. CFD-DEM is one of powerful methods to study the fundamentals of gas-solid flow, as it takes the particle-particle and particle-wall collisions into account. But the time consumption is one of major limitations for its application. In this paper, a three-dimensional CFD-DEM model which ignores the effect of void fraction to the gas phase is used to simulate the dilute gas-solid flow. Gas-solid flows in different types of bends including horizontal-vertical, vertical-horizontal and horizontal-horizontal 90° bends are studied. The present CFD-DEM model is verified by compared the rope structure with the result for traditional CFD-DEM model in horizontal-vertical case. Compared the particle rope dispersion in different types of bends, the rope disperses more quickly in the vertical-horizontal case than others, and the solid flow structure is the most complicated in the horizontal- horizontal case. As their various solid flow structures, the collision data of three cases also seem different
Local electrostatic moments and periodic boundary conditions
Energy Technology Data Exchange (ETDEWEB)
Schultz, P.A. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)
1999-07-01
Electronic structure calculations frequently invoke the supercell approximation and solve for electrostatic potentials within periodic boundary conditions. For systems that are electronically charged, or contain dipole (or higher) moments, this artifice introduces spurious potentials due to interactions between the system and multipole moments of its periodic images in aperiodic directions. I describe a method to handle properly the multipole moments of the electron density in electronic structure calculations using supercells. The density is divided into two pieces. A model local density is constructed to match multipole moments of the full density. The potential from this piece is obtained treating this density as isolated. With the density of this local-moment countercharge removed from the full density, the remainder density no longer contains moments with long-range potentials, and its electrostatic potential can be evaluated accurately using periodic boundary conditions. {copyright} {ital 1999} {ital The American Physical Society}
Magnetic Moment Fields in Dense Relativistic Plasma Interacting with Laser Radiations
Directory of Open Access Journals (Sweden)
B.Ghosh1* , S.N.Paul 1 , S.Bannerjee2 and C.Das3
2013-04-01
Full Text Available Theory of the generation of magnetic moment field from resonant interaction of three high frequency electromagnetic waves in un-magnetized dense electron plasma is developed including the relativistic change of electron mass. It is shown that the inclusion of relativistic effect enhances the magnetic moment field. For high intensity laser beams this moment field may be of the order of a few mega gauss. Such a high magnetic field can considerably affect the transport of electrons in fusion plasma
COMPARATIVE STUDY ON BENDING LOSS BETWEEN DIFFERENT S-SHAPED WAVEGUIDE BENDS USING MATRIX METHOD
Directory of Open Access Journals (Sweden)
Koushik Bhattacharya
2013-02-01
Full Text Available Bending loss in the waveguide as well as the leakage losses and absorption losses along with a comparative study among different types of S-shaped bend structures has been computed with the help of a simple matrix method.This method needs simple 2×2 matrix multiplication. The effective-index profile of the bended waveguide is then transformed to an equivalent straight waveguide with the help of a suitable mapping technique and is partitioned into large number of thin sections of different refractive indices. The transfer matrix of the two adjacent layers will be a 2×2 matrix relating the field components in adjacent layers. The total transfer matrix is obtained through multiplication of all these transfer matrices. The excitation efficiency of the wave in the guiding layer shows a Lorentzian profile. The power attenuation coefficient of the bent waveguide is the full-width-half-maximum (FWHM of this peak .Now the transition losses and pure bending losses can be computed from these FWHM datas.The computation technique is quite fast and it is applicable for any waveguide having different parameters and wavelength of light for both polarizations(TE and TM.
Noncommutative QED and anomalous dipole moments
International Nuclear Information System (INIS)
We study QED on noncommutative spaces, NCQED. In particular we present the detailed calculation for the noncommutative electron-photon vertex and show that the Ward identity is satisfied. We discuss that in the noncommutative case moving electron will show electric dipole effects. In addition, we work out the electric and magnetic dipole moments up to one loop level. For the magnetic moment we show that noncommutative electron has an intrinsic (spin independent) magnetic moment. (author)
What's the value in more moments?
Daley, Timothy; Smith, Andrew D
2016-01-01
The moment-based non-parametric species richness estimator of Chao is one of the most widely used estimators for the number of unobserved species in a sampling experiment. This is due in large part to its simplicity and robustness. This simplicity can also be a drawback, as it only uses a small amount of information contained in the observed experiment, essentially only the first moment. Previous authors, specifically Harris and Chao, have presented a general moment-based framework for estima...
Risk-adjusted option-implied moments
Brinkmann, Felix; KORN Olaf
2014-01-01
Option-implied moments, like implied volatility, contain useful information about an underlying asset's return distribution, but are derived under the risk-neutral probability measure. This paper shows how to convert risk-neutral moments into the corresponding physical ones. The main theoretical result expresses moments under the physical probability measure in terms of observed option prices and the preferences of a representative investor. Based on this result, we investigate several empiri...
Option Implied Trees and Implied Moments
silvia Muzzioli; Alessio Ruggieri
2013-01-01
Implied trees are simple non-parametric discretizations of one- or two-dimension diffusions, aimed at introducing non-constant volatility in an option pricing model. The aim of the paper is twofold. First we investigate the ability of different option implied trees in pricing European options. Second, we compare the implied moments obtained with the use of option implied trees with the risk–neutral moments obtained with the use of Bakshi et al. (2003) formula and with realised physical moment...
Six-quark bag, exchange currents and trinucleon magnetic moments
International Nuclear Information System (INIS)
The magnetic moments of 3H and 3He are reexamined in the Karl-Miller-Rafelski model of six-quark bag formation. Realistic three-nucleon wavefunctions are taken, and long-range one-pion exchange current corrections are included. It is concluded that the model is compatible with the data. (orig.)
Elasticity of randomly diluted honeycomb and diamond lattices with bending forces.
Liarte, Danilo B; Stenull, O; Mao, Xiaoming; Lubensky, T C
2016-04-27
We use numerical simulations and an effective-medium theory to study the rigidity percolation transition of the honeycomb and diamond lattices when weak bond-bending forces are included. We use a rotationally invariant bond-bending potential, which, in contrast to the Keating potential, does not involve any stretching. As a result, the bulk modulus does not depend on the bending stiffness κ. We obtain scaling functions for the behavior of some elastic moduli in the limits of small [Formula: see text], and small [Formula: see text], where [Formula: see text] is an occupation probability of each bond, and [Formula: see text] is the critical probability at which rigidity percolation occurs. We find good quantitative agreement between effective-medium theory and simulations for both lattices for [Formula: see text] close to one. PMID:27023434
Correlation of in-plane bending test and FEA results for thin-walled elbows
International Nuclear Information System (INIS)
The objective of this study is to validate a finite element analysis (FEA) simulation methodology to predict the global behavior of thin-walled elbows subjected to in-plane bending. Two in-plane closing mode bending tests and one in-plane opening mode bending test were conducted on 2'' schedule 10 elbows, and a nonlinear FEA procedure was used to simulate the tests. A detailed FEA study was carried out to determine the relative importance of weld size and location, measured wall thicknesses, and original cross-section dimensions on the reconciliation results. When the weld bead was included in the analysis, the reconciliation results for load-displacement behavior and some of the strain measurements were excellent. For those cases in which the strain measurements reconciliations were not so good, a possible explanation is provided
The Moment Guided Monte Carlo Method
Degond, Pierre; Pareschi, Lorenzo
2009-01-01
In this work we propose a new approach for the numerical simulation of kinetic equations through Monte Carlo schemes. We introduce a new technique which permits to reduce the variance of particle methods through a matching with a set of suitable macroscopic moment equations. In order to guarantee that the moment equations provide the correct solutions, they are coupled to the kinetic equation through a non equilibrium term. The basic idea, on which the method relies, consists in guiding the particle positions and velocities through moment equations so that the concurrent solution of the moment and kinetic models furnishes the same macroscopic quantities.
A uniform parameterization of moment tensors
Tape, C.; Tape, W.
2015-12-01
A moment tensor is a 3 x 3 symmetric matrix that expresses an earthquake source. We construct a parameterization of the five-dimensional space of all moment tensors of unit norm. The coordinates associated with the parameterization are closely related to moment tensor orientations and source types. The parameterization is uniform, in the sense that equal volumes in the coordinate domain of the parameterization correspond to equal volumes of moment tensors. Uniformly distributed points in the coordinate domain therefore give uniformly distributed moment tensors. A cartesian grid in the coordinate domain can be used to search efficiently over moment tensors. We find that uniformly distributed moment tensors have uniformly distributed orientations (eigenframes), but that their source types (eigenvalue triples) are distributed so as to favor double couples. An appropriate choice of a priori moment tensor probability is a prerequisite for parameter estimation. As a seemingly sensible choice, we consider the homogeneous probability, in which equal volumes of moment tensors are equally likely. We believe that it will lead to improved characterization of source processes.
Analysis of scaled-factorial-moment data
International Nuclear Information System (INIS)
We discuss the two standard constructions used in the search for intermittency, the exclusive and inclusive scaled factorial moments. We propose the use of a new scaled factorial moment that reduces to the exclusive moment in the appropriate limit and is free of undesirable multiplicity correlations that are contained in the inclusive moment. We show that there are some similarities among most of the models that have been proposed to explain factorial-moment data, and that these similarities can be used to increase the efficiency of testing these models. We begin by calculating factorial moments from a simple independent-cluster model that assumes only approximate boost invariance of the cluster rapidity distribution and an approximate relation among the moments of the cluster multiplicity distribution. We find two scaling laws that are essentially model independent. The first scaling law relates the moments to each other with a simple formula, indicating that the different factorial moments are not independent. The second scaling law relates samples with different rapidity densities. We find evidence for much larger clusters in heavy-ion data than in light-ion data, indicating possible spatial intermittency in the heavy-ion events
Practical Fast Computation of Zernike Moments
Institute of Scientific and Technical Information of China (English)
Al-Rawi Mohammed; 杨杰
2002-01-01
The fast computation of Zernike moments from normalized geometric moments has been developed in this paper. The computation is multiplication free and only additions are needed to generate Zernike moments. Geometric moments are generated using Hatamian's filter up to high orders by a very simple and straightforward computation scheme. Other kinds of moments (e.g., Legendre, pseudo Zernike) can be computed using the same algorithm after giving the proper transformations that state their relations to geometric moments. Proper normalizations of geometric moments are necessary so that the method can be used in the efficient computation of Zernike moments. To ensure fair comparisons, recursive algorithms are used to generate Zernike polynomials and other coefficients. The computational complexity model and test programs show that the speed-up factor of the proposed algorithm is superior with respect to other fast and/or direct computations. It perhaps is the first time that Zernike moments can be computed in real time rates, which encourages the use of Zernike momentfeatures in different image retrieval systems that support huge databases such as the XM experimental model stated for the MPEG-7 experimental core. It is concluded that choosing direct computation would be impractical.
Invariant Image Watermarking Using Accurate Zernike Moments
Directory of Open Access Journals (Sweden)
Ismail A. Ismail
2010-01-01
Full Text Available problem statement: Digital image watermarking is the most popular method for image authentication, copyright protection and content description. Zernike moments are the most widely used moments in image processing and pattern recognition. The magnitudes of Zernike moments are rotation invariant so they can be used just as a watermark signal or be further modified to carry embedded data. The computed Zernike moments in Cartesian coordinate are not accurate due to geometrical and numerical error. Approach: In this study, we employed a robust image-watermarking algorithm using accurate Zernike moments. These moments are computed in polar coordinate, where both approximation and geometric errors are removed. Accurate Zernike moments are used in image watermarking and proved to be robust against different kind of geometric attacks. The performance of the proposed algorithm is evaluated using standard images. Results: Experimental results show that, accurate Zernike moments achieve higher degree of robustness than those approximated ones against rotation, scaling, flipping, shearing and affine transformation. Conclusion: By computing accurate Zernike moments, the embedded bits watermark can be extracted at low error rate.
Optimized Set of RST Moment Invariants
Directory of Open Access Journals (Sweden)
Khalid M. Hosny
2008-01-01
Full Text Available Moment invariants are widely used in image processing, pattern recognition and computer vision. Several methods and algorithms have been proposed for fast and efficient calculation of moment's invariants where numerical approximation errors are involved in most of these methods. In this paper, an optimized set of moment invariants with respect to rotation, scaling and translation is presented. An accurate method is used for exact computation of moment invariants for gray level images. A fast algorithm is applied to accelerate the process of computation. Error analysis is presented and a comparison with other conventional methods is performed. The obtained results explain the superiority of the proposed method.
Piecewise Filter of Infrared Image Based on Moment Theory
Institute of Scientific and Technical Information of China (English)
GAO Yang; LI Yan-jun; ZHANG Ke
2007-01-01
The disadvantages of IR images mostly include high noise, blurry edge and so on. The characteristics make the existent smoothing methods ineffective in preserving edge. To solve this problem, a piecewise moment filter (PMF) is put forward. By using moment and piecewise linear theory, the filter can preserve edge. Based on the statistical model of random noise, a related-coefficient method is presented to estimate the variance of noise. The edge region and model are then detected by the estimated variance. The expectation of first-order derivatives is used in getting the reliable offset of edge.At last, a fast moment filter of double-stair edge model is used to gain the piecewise smoothing results and reduce the calculation. The experimental result shows that the new method has a better capability than other methods in suppressing noise and preserving edge.
1998-05-01
illustrates how the appearance of a stellar image at the focal plane is fully controllable. Fast and thorough optical adjustment ensures the best possible optical quality at all times . 9. Image Quality of the VLT This diagram demonstrates that First Light specifications have been fully met and, more impressively, that the actual VLT performance is sometimes already within the more stringent specifications that were expected to be fulfilled only three years from now. The final steps before "First Light" The final, critical testing phase commenced with the installation of the 8.2-m primary (at that time still uncoated) Zerodur mirror and 1.1-m secondary Beryllium mirror during the second half of April. The optics were then gradually brought into position during carefully planned, successive adjustments. Due to the full integration of an advanced, active control system into the VLT concept, this delicate process went amazingly fast, especially when compared to other ground-based telescopes. It included a number of short test exposures in early May, first with the Guide Camera that is used to steer the telescope. Later, some exposures were made with the Test Camera mounted just below the main mirror at the Cassegrain Focus, in a central space inside the mirror cell. It will continue to be used during the upcoming Commissioning Phase, until the first major instruments (FORS and ISAAC) are attached to the UT1, later in 1998. The 8.2-m mirror was successfully aluminized at the Paranal Mirror Coating facility on May 20 and was reattached to the telescope tube the day thereafter, cf. ESO PR Photos 13a-e/98 and ESO PR Photos 14a-i/98. Further test exposures were then made to check the proper functioning of the telescope mechanics, optics and electronics. This has lead up to the moment of First Light , i.e. the time when the telescope is considered able to produce the first, astronomically useful images. Despite an intervening spell of bad atmospheric conditions, this important event
Institute of Scientific and Technical Information of China (English)
张海波; 彭立山; 白雷杰; 赵志伟; 刘旭; 巩忠旺
2014-01-01
针对X70钢级大径厚比热煨弯管的制造难点，合理改进了弯管机组设备，优化弯管成型工艺参数，精确测量和控制弯管煨制温度和速度，开发了一套完整的大径厚比弯管制造工艺，该工艺解决了大径厚比弯管成型后管体椭圆度超标和弯管综合力学性能差等问题。采用该工艺进行了单根和批量生产，产品符合伊拉克MOEP工程《弯管技术规格书》要求。%In this article,according to the manufacturing difficulties of X70 grade hot bending bends with large diameter-thickness ratio,it reasonably improved bends unit equipment,optimized bends forming process parameters,accurately measured and controlled the temperature and speed in bends forming process. A complete set of large diameter-thickness ratio bends manufacturing process was developed, it resolved some problems,including ovality of bends body exceeding the standard requirements,the comprehensive mechanic properties not good,and other manufacturing difficulties. It adopted the above manufacturing process to conduct single and bulk production, the products accord with the requirements of Iraq MOEP Project Technical Specification for Bending Bends.
Bending strain tolerance of MgB2 superconducting wires
Kováč, P.; Hušek, I.; Melišek, T.; Kulich, M.; Kopera, L.
2016-04-01
This work describes the strain tolerance of MgB2 superconductors subjected to variable bending stresses. Bending of MgB2 wire was done at room temperature in different modes: (i) direct bending of straight annealed samples to variable diameters and by (ii) indirect bending by straightening of bent and annealed samples. I c-bending strain characteristics of samples made by in situ PIT and by the internal magnesium diffusion (IMD) process were measured at 4.2 K. The results show a good agreement between the direct and indirect bending mode, which allows easier estimation of limits important for the winding process of MgB2 superconductors with brittle filaments. A comparison of MgB2 wires made by in situ PIT and IMD processes showed improved strain tolerance for IMD due to better grain connectivity the low annealing temperature, which does not appear to reduce the mechanical strength of sheath material.
Reduction Bending of Thin Crystalline Silicon Solar Cells
Institute of Scientific and Technical Information of China (English)
SHEN Lan-xian; LIU Zu-ming; LIAO Hua; TU Jie-lei; DENG Shu-kang
2009-01-01
Reported are the results of reduction the bending of thin crystalline silicon solar ceils after printing and sintering of back electrode by changing the back electrode paste and adjusting the screen printing parameters without effecting the electrical properties of the cell. Theory and experiments showed that the bending of the cell is changed with its thickness of suhstrate, the thinner cell, the more serious bending. The bending of the cell is decreased with the thickness decrease of the back contact paste. The substrate with the thickness of 190μm printing with sheet aluminum paste shows a relatively lower bend compared with that of the substrate printing with ordinary aluminum paste, and the minimum bend is 0.55 mm which is reduced by52%.
International Nuclear Information System (INIS)
In order to study the protection offered by reinforced concrete shell structures against soft projectiles impacts, we need first to characterize that kind of impact. In this document, we propose a new unified classification of shocks, allowing to distinguish soft and hard impacts. We show that aircraft crash, like every soft impact, produces bending and shear waves, which generate global and local damage: concrete cracking and reinforcement yielding in the whole structure, and possible perforation with a yield cone in the impact area. To model these phenomena we propose two computational tools. The first one is a membrane-bending non linear constitutive law for reinforced concrete slabs. This global model, using resultant variables, can simulate concrete cracking through damage theory and inelastic strains through plasticity theory. The Johansen bending yield criterion is improved to account for membrane effects. This material law has been implemented in Europlexus, an industrial finite element software for fast dynamics, and validated by comparison with experimental tests and other computational models. The second simulation tool is a perforation criterion for reinforced concrete slabs. It is a static criterion depending on bending moment, normal force, and shear force, and derived using limit analysis. We prove that it is possible to predict perforation in case of soft impact, applying this criterion on stress resultant variables coming from a dynamic computation. (author)
The Italian-Americans of the South Bend-Mishawaka Area.
Fotia, Elizabeth R.; Rasmussen, Karen
Developed as part of an ethnic heritage studies program, this historical narrative of Italian Americans can enhance cultural awareness. This document presents the story of Italians beginning with cultural roots in Italy and their subsequent emigration to the United States, including to South Bend, Indiana. Four major areas are explored. An account…
Validation of cfd and simplified models with experimental data for multiphase flow in bends
Nennie, E.D.; Belfroid, S.P.C.; O'Mahoney, T.S.D.
2013-01-01
In this paper details of the measurement results of the forces on the bends in a 4" setup are compared to two models. The first model is a simple analytical model and is used to estimate the forces. In the second model, CFD is used. In the experiments only resulting forces, including upstream and do
49 CFR 192.315 - Wrinkle bends in steel pipe.
2010-10-01
... 49 Transportation 3 2010-10-01 2010-10-01 false Wrinkle bends in steel pipe. 192.315 Section 192... Transmission Lines and Mains § 192.315 Wrinkle bends in steel pipe. (a) A wrinkle bend may not be made on steel pipe to be operated at a pressure that produces a hoop stress of 30 percent, or more, of SMYS. (b)...
Bamboo Taper Effect on Third Point Loading Bending Test
Naresworo Nugroho; Effendi Tri Bahtiar
2013-01-01
Geometrical shape of bamboo usually assumed as tapered hollow pipe. This study proved that the dimensional changes along the bamboo stem significantly affected to its Modulus of Rupture (SR) value which measured from third point loading bending test. Therefore if the bending test applied using third point loading configuration, the SR value should be adjusted by strength ratio of taper (Ct). Ct is theratio between (SR) calculated in the center span and the maximum bending stress along the bam...
Bending instability characteristics of double-walled carbon nanotubes
Wang, Q.; Hu, T.; Chen, G.; Jiang, Q.
2005-01-01
The bending instability characteristics of double-walled carbon nanotubes (DWNTs) of various configurations are studied using a hybrid approach in which the deformation-induced increase of the intratube interaction energy is modeled with the bending deformation energy using the elastic theory of beams. The intertube interaction energy is calculated using the van der Waals interatomic potential. This study shows that the bending instability may take place through the formation of a single kink...
Compliance measurements of chevron notched four point bend specimen
Calomino, Anthony; Bubsey, Raymond; Ghosn, Louis J.
1994-01-01
The experimental stress intensity factors for various chevron notched four point bend specimens are presented. The experimental compliance is verified using the analytical solution for a straight through crack four point bend specimen and the boundary integral equation method for one chevron geometry. Excellent agreement is obtained between the experimental and analytical results. In this report, stress intensity factors, loading displacements and crack mouth opening displacements are reported for different crack lengths and different chevron geometries, under four point bend loading condition.
Behaviour of a Moment Resisting Composite Steel and Concrete Joint Under Alternate Loading
Institute of Scientific and Technical Information of China (English)
Alberto Zanchettin; Bruno Briseghella; Tobia Zordan; Junqing Xue
2011-01-01
The authors show the results of a study conducted on a joint connecting a concrete column to a composite steel concrete floor, subjected to tension on the beams as a result of the decomposition of sagging bending moment. The beam to column connection is achieved by means of headed studs welded to the beam and embedded in the concrete cast. Five different configurations have been tested at failure and the results are compared to formulae proposed in literature. Different degrees of ductility, reliability and strength have been obtained varying geometry and reinforcement ratio on the joints tested.
Directory of Open Access Journals (Sweden)
Jose A. Rodríguez-Gutiérrez
2014-07-01
Full Text Available An analytical method that calculates both the short- and long-term response of slender columns made of high-strength concrete (HSC and tubes filled with concrete with generalized end conditions and subjected to transverse loads along the span and axial load at the ends (causing a single or double curvature under uniaxial or biaxial bending is presented. The proposed method, which is an extension of a method previously developed by the authors, is capable of predicting not only the complete load-rotation and load-deflection curves (both the ascending and descending parts but also the maximum load capacity. The columns that can be analyzed include solid and hollow (rectangular, circular, oval, C-, T-, L-, or any arbitrary shape cross sections and columns made of circular and rectangular steel tubes filled with HSC. The fiber method is used to calculate the moment-curvature diagrams at different levels of the applied axial load (i.e., the M-P-φ curves, and the Gauss method of integration (for the sum of the contributions of the fibers parallel to the neutral axis is used to calculate the lateral rotations and deflections along the column span. Long-term effects, such as creep and shrinkage of the concrete, are also included. However, the effects of the shear deformations and torsion along the member are not included. The validity of the proposed method is presented in a companion paper and compared against the experimental results for over seventy column specimens reported in the technical literature by different researchers.
PERMEABILITY OF SALTSTONE MEASUREMENT BY BEAM BENDING
International Nuclear Information System (INIS)
One of the goals of the Saltstone variability study is to identify (and, quantify the impact of) the operational and compositional variables that control or influence the important processing and performance properties of Saltstone mixes. A performance property for Saltstone mixes that is important but not routinely measured is the liquid permeability or saturated hydraulic conductivity of the cured Saltstone mix. The value for the saturated hydraulic conductivity is an input into the Performance Assessment for the SRS Z-Area vaults. Therefore, it is important to have a method available that allows for an accurate and reproducible measurement of permeability quickly and inexpensively. One such method that could potentially meet these requirements for the measurement of saturated hydraulic conductivity is the technique of beam bending, developed by Professor George Scherer at Princeton University. In order to determine the feasibility of this technique for Saltstone mixes, a summer student, David Feliciano, was hired to work at Princeton under the direction of George Scherer. This report details the results of this study which demonstrated the feasibility and applicability of the beam bending method to measurement of permeability of Saltstone samples. This research effort used samples made at Princeton from a Modular Caustic side solvent extraction Unit based simulant (MCU) and premix at a water to premix ratio of 0.60. The saturated hydraulic conductivities for these mixes were measured by the beam bending technique and the values determined were of the order of 1.4 to 3.4 x 10-9 cm/sec. These values of hydraulic conductivity are consistent with independently measured values of this property on similar MCU based mixes by Dixon and Phifer. These values are also consistent with the hydraulic conductivity of a generic Saltstone mix measured by Langton in 1985. The high water to premix ratio used for Saltstone along with the relatively low degree of hydration for MCU
Static Fatigue of Optical Fibers in Bending
Roberts, D.; Cuellar, E.; Middleman, L.; Zucker, J.
1987-02-01
While delayed fracture, or static fatigue, of optical fibers is well known, it is not well understood, and the prediction of the time to failure under a given set of conditions can be problematic. Unlike short term fracture, which is quite well understood and quantified in terms of the theory of linear elastic fracture mechanics, the long term strength remains empirical. The goal of this study is to determine the design criteria for optical fibers subjected to long term applied mechanical loads. One difficulty in making lifetime predictions, as pointed out by Matthewson (Reference 1) and others, is that predictions made from data taken in tension and in bending do not agree. Another difficulty is the statistical nature of the fracture of glass. In making lifetime predictions it becomes important therefore that one (a) have ample data for statistical analysis and (b) have data for the loading configuration of interest. This is the purpose of our work. Since there is less data available in bending, and since several applications (such as wiring in aircraft and missiles) require bending, the data are taken in that configuration. The most significant finding in our work so far is the very large difference in static fatigue behavior between buffer coatings. Chandan and Kalish (Reference 2) and others have reported static fatigue curves, log (time to failure) versus log (applied stress), which are not linear, but rather bimodal. Our study confirms this result, but so far only for acrylate coated fibers. Silicone coated fibers show unimodal behavior. That is, the log (time to failure) versus log (applied stress) curve is linear, at least on the time scale studied so far. Data for acrylate coated fibers at 80°C in water are linear only for time scales of about one day, where a pronounced "knee" is observed. Data for silicone coated fibers under the same conditions are linear up to at least 6 months. Longer time scale tests and tests on fibers with other buffer materials
Bend sensors based on periodically-tapered soft glass fibers
Wang, Y.; Richardson, D. J.; Brambilla, G; Feng, X.; Petrovich, M.N.; Ding, M.; Song, Z.(Central China Normal University, Wuhan, China)
2011-01-01
We demonstrate a technique for tapering periodically an all-solid soft glass fiber consisting of two types of lead silicate glasses by the use of a CO2 laser and investigate the bend sensing applications of the periodically-tapered soft glass fiber. Such a soft glass fiber with periodic microtapers could be used to develop a promising bend sensor with a sensitivity of ?27.75 ?W/m-1 by means of measuring the bend-induced change of light intensity. The proposed bend sensor exhibits a very low m...
A preliminary bending fatigue spectrum for steel monostrand cables
DEFF Research Database (Denmark)
Winkler, Jan; Fischer, Gregor; Georgakis, Christos T.; Kotas, Agnieszka
2011-01-01
This paper presents the results of the experimental study on the bending fatigue resistance of high-strength steel monostrand cables. From the conducted fatigue tests in the high-stress, low-cycle region, a preliminary bending fatigue spectrum is derived for the estimation of monostrand cable...... service life expectancy. The presented preliminary bending fatigue spectrum of high-strength monostrands is currently unavailable in the published literature. The presented results provide relevant information on the bending mechanism and fatigue characteristics of monostrand steel cables in tension and...
SRI CAT Section 1 bending magnet beamline description
International Nuclear Information System (INIS)
This report discusses: APS bending magnet source; beamline layout; beamline optical components; beamline operation; time-resolved studies station; polarization studies station; and commissioning and operational schedule
Calo, Victor M.
2014-01-01
We analyze the discontinuous Petrov-Galerkin (DPG) method with optimal test functions when applied to solve the Reissner-Mindlin model of plate bending. We prove that the hybrid variational formulation underlying the DPG method is well-posed (stable) with a thickness-dependent constant in a norm encompassing the L2-norms of the bending moment, the shear force, the transverse deflection and the rotation vector. We then construct a numerical solution scheme based on quadrilateral scalar and vector finite elements of degree p. We show that for affine meshes the discretization inherits the stability of the continuous formulation provided that the optimal test functions are approximated by polynomials of degree p+3. We prove a theoretical error estimate in terms of the mesh size h and polynomial degree p and demonstrate numerical convergence on affine as well as non-affine mesh sequences. © 2013 Elsevier Ltd. All rights reserved.
A Unified Methodology for Computing Accurate Quaternion Color Moments and Moment Invariants.
Karakasis, Evangelos G; Papakostas, George A; Koulouriotis, Dimitrios E; Tourassis, Vassilios D
2014-02-01
In this paper, a general framework for computing accurate quaternion color moments and their corresponding invariants is proposed. The proposed unified scheme arose by studying the characteristics of different orthogonal polynomials. These polynomials are used as kernels in order to form moments, the invariants of which can easily be derived. The resulted scheme permits the usage of any polynomial-like kernel in a unified and consistent way. The resulted moments and moment invariants demonstrate robustness to noisy conditions and high discriminative power. Additionally, in the case of continuous moments, accurate computations take place to avoid approximation errors. Based on this general methodology, the quaternion Tchebichef, Krawtchouk, Dual Hahn, Legendre, orthogonal Fourier-Mellin, pseudo Zernike and Zernike color moments, and their corresponding invariants are introduced. A selected paradigm presents the reconstruction capability of each moment family, whereas proper classification scenarios evaluate the performance of color moment invariants. PMID:24216719
Energy Technology Data Exchange (ETDEWEB)
Fukuda, H. [Science Univ. of Tokyo (Japan)
1998-05-15
In the second generation report of 1982 fiscal year, most of testing methods at that time are included. For bending test, not only the bending testing method of hard plastics in ISO 178-1975, that of woven glass roving reinforced plastics in ISO 3597-1971, that of hard plastics in JIS K7203-1982, and that of plastics and electrical insulating materials in ASTM D790-80, but also private companies` specifications as well as BS, DIN, NF and so forth are recorded. In this paper, to avoid duplication with them, those established after them are describe. In JIS K7055-1987 established in following of JIS K7203, only glass fiber reinforced plastics is limited to specify the three points bending (A method) and the four points bending (B method). In JIS K7074-1988, a bending testing method of carbon fiber reinforced plastics is specified. As a research on bending test, stress distribution at bending test, effect of insert material, simple bending, compression bending and so on are conducted. 15 refs., 9 figs., 3 tabs.
Kim, Byoung-Joon; Shin, Hae-A.-Seul; Lee, Ji-Hoon; Joo, Young-Chang
2016-06-01
The electrical reliability of a multi-layer metal film on a polymer substrate during cyclic inner bending and outer bending is investigated using a bending fatigue system. The electrical resistance of a Cu film on a polymer substrate during cyclic outer bending increases due to fatigue damage formation, such as cracks and extrusion. Cyclic inner bending also leads to fatigue damage and a similar increase in the electrical resistance. In a sample having a NiCr under-layer, however, the electrical resistance increases significantly during outer bending but not during inner bending mode. Cross-sectional observations reveal that brittle cracking in the hard under-layer results in different fatigue behaviors according to the stress mode. By applying an Al over-layer, the fatigue resistance is improved during both outer bending and inner bending by suppressing fatigue damage formation. The effects of the position, materials, and thickness of the inter-layer on the electrical reliability of a multi-layer sample are also investigated. This study can provide meaningful information for designing a multi-layer structure under various mechanical deformations including tensile and compressive stress.
Predicting Robust Learning with the Visual Form of the Moment-by-Moment Learning Curve
Baker, Ryan S.; Hershkovitz, Arnon; Rossi, Lisa M.; Goldstein, Adam B.; Gowda, Sujith M.
2013-01-01
We present a new method for analyzing a student's learning over time for a specific skill: analysis of the graph of the student's moment-by-moment learning over time. Moment-by-moment learning is calculated using a data-mined model that assesses the probability that a student learned a skill or concept at a specific time during learning…
Acoustic emission monitoring of recycled aggregate concrete under bending
Tsoumani, A. A.; Barkoula, N.-M.; Matikas, T. E.
2015-03-01
The amount of construction and demolition waste has increased considerably over the last few years, making desirable the reuse of this waste in the concrete industry. In the present study concrete specimens are subjected at the age of 28 days to four-point bending with concurrent monitoring of their acoustic emission (AE) activity. Several concrete mixtures prepared using recycled aggregates at various percentages of the total coarse aggregate and also a reference mix using natural aggregates, were included to investigate their influence of the recycled aggregates on the load bearing capacity, as well as on the fracture mechanisms. The results reveal that for low levels of substitution the influence of using recycled aggregates on the flexural strength is negligible while higher levels of substitution lead into its deterioration. The total AE activity, as well as the AE signals emitted during failure, was related to flexural strength. The results obtained during test processing were found to be in agreement with visual observation.
Stabilization of helical macromolecular phases by confined bending
Williams, Matthew J
2015-01-01
By means of extensive replica-exchange simulations of generic coarse-grained models for helical polymers, we systematically investigate the structural transitions into all possible helical phases for flexible and semiflexible elastic polymers with self-interaction under the influence of torsion barriers. The competing interactions lead to a variety of conformational phases including disordered helical arrangements, single helices, and ordered, tertiary helix bundles. Most remarkably, we find that a bending restraint entails a clear separation and stabilization of the helical phases. This aids in understanding why semiflexible polymers such as double-stranded DNA tend to form pronounced helical structures and proteins often exhibit an abundance of helical structures, such as helix bundles, within their tertiary structure.
A mechanical model for FRP-strengthened beams in bending
Directory of Open Access Journals (Sweden)
P. S. Valvo
2012-10-01
Full Text Available We analyse the problem of a simply supported beam, strengthened with a fibre-reinforced polymer (FRP strip bonded to its intrados and subjected to bending couples applied to its end sections. A mechanical model is proposed, whereby the beam and FRP strip are modelled according to classical beam theory, while the adhesive and its neighbouring layers are modelled as an interface having a piecewise linear constitutive law defined over three intervals (elastic response – softening response – debonding. The model is described by a set of differential equations with appropriate boundary conditions. An analytical solution to the problem is determined, including explicit expressions for the internal forces, displacements and interfacial stresses. The model predicts an overall non-linear mechanical response for the strengthened beam, ranging over several stages: from linearly elastic behaviour to damage, until the complete detachment of the FRP reinforcement.
Geometrically nonlinear bending analysis of laminated composite plate
Dash, Padmanav; Singh, B. N.
2010-10-01
In this work, a transverse bending of shear deformable laminated composite plates in Green-Lagrange sense accounting for the transverse shear and large rotations are presented. Governing equations are developed in the framework of higher order shear deformation theory. All higher order terms arising from nonlinear strain-displacement relations are included in the formulation. The present plate theory satisfies zero transverse shear strains conditions at the top and bottom surfaces of the plate in von-Karman sense. A C0 isoparametric finite element is developed for the present nonlinear model. Numerical results for the laminated composite plates of orthotropic materials with different system parameters and boundary conditions are found out. The results are also compared with those available in the literature. Some new results with different parameters are also presented.
Design Study: ELENA Bending Magnet Prototype
Schoerling, D
2013-01-01
The ELENA bending magnet prototype shall prove that the proposed design meets the requirements set by the ELENA beam dynamics. The following points will be discussed in detail: (i) production process of a magnetic yoke diluted with stainless steel plates, (ii) the stability and repeatability of the field homogeneity of such a yoke over the full working range, (iii) choice of soft magnetic steel, (iv) hysteresis effects, (v) mechanical deformations, (vi) thermal insulation to intercept heat load from baking for activation of NEG coating in the vacuum chamber, (vii) end shim design. In order to verify these points the following measurements will be performed: (i) Hall probe scanning, (ii) integrated field homogeneity measurement (DC), (iii) integrated field homogeneity measurement (AC).
Bending the Cost Curve in Childhood Cancer.
Russell, Heidi; Bernhardt, M Brooke
2016-08-01
Healthcare for children with cancer costs significantly more than other children. Cost reduction efforts aimed toward relatively small populations of patients that use a disproportionate amount of care, like childhood cancer, could have a dramatic impact on healthcare spending. The aims of this review are to provide stakeholders with an overview of the drivers of financial costs of childhood cancer and to identify possible directions to curb or decrease these costs. Costs are incurred throughout the spectrum of care. Recent trends in pharmaceutical costs, evidence identifying the contribution of administration costs, and overuse of surveillance studies are described. Awareness of cost and value, i.e., the outcome achieved per dollar or burden spent, in delivery of care and research is necessary to bend the cost curve. Incorporation of these dimensions of care requires methodology development, prioritization, and ethical balance. PMID:27193602
Bending of pipes with inconel cladding
Energy Technology Data Exchange (ETDEWEB)
Nachpitz, Leonardo; Menezes, Carlos Eduardo B.; Vieira, Carlos R. Tavares [Primus Processamento de Tubos S.A. (PROTUBO), Macae, RJ (Brazil)
2009-07-01
The high-frequency induction bending process, using API pipes coated with Inconel 625 reconciled to a mechanical transformation for a higher degree of resistance, was developed through a careful specification and control of the manufacturing parameters and inherent heat treatments. The effects of this technology were investigated by a qualification process consisting of a sequence of tests and acceptance criteria typically required by the offshore industry, and through the obtained results was proved the effectiveness of this entire manufacturing process, without causing interference in the properties and the quality of the inconel cladding, adding a gain of resistance to the base material, guaranteed by the requirements of the API 5L Standard. (author)
Separation of blood in microchannel bends
Blattert, Christoph; Jurischka, Reinhold; Schoth, Andreas; Kerth, Paul; Menz, Wolfgang
2004-01-01
Biological applications of micro assay devices require integrated on-chip microfluidics for separation of plasma or serum from blood. This is achieved by a new blood separation technique based on a microchannel bend structure developed within the collaborative Micro-Tele-BioChip (μTBC) project co-funded by the German Ministry For Education and Research (BMBF). Different prototype polymer chips have been manufactured with an UV-LIGA process and hot embossing technology. The separation efficiency of these chips has been determined by experimental measurements using human whole blood. Results show different separation efficiencies for cells and plasma depending on microchannel geometry and blood sample characteristics and suggest an alternative blood separation method as compared to existing micro separation technologies.
On the gravitational seesaw and light bending
Accioly, Antonio; Shapiro, Ilya L
2016-01-01
Local gravitational theories with more than four derivatives are superrenormalizable, and also may be unitary in the Lee-Wick sense. It makes sense to study low-energy properties of these theories, e.g., identify observables which might be useful for experimental detection of higher derivatives. Using an analogy with neutrino Physics, we explore the possibility of a gravitational seesaw mechanism, in which several dimensional parameters of the same order of magnitude produce a hierarchy in the masses of propagating particles and make a relatively light degree of freedom detectable by frequency dependence in the gravitational light bending. It turns out that such a seesaw mechanism in the six- and more-derivative theories is unable to reduce the lightest mass more than in the simplest four-derivative model. Adding more derivatives can only make heavier masses even larger. This fact may be favorable for protecting the theory from instabilities, but makes experimental detection of higher derivatives more difficu...
Factors affecting U-bend cracking
International Nuclear Information System (INIS)
Stress corrosion cracking of alloy 600 in pure water is assumed to be the damaging process of a large number of small radius U-bends of PWR steam generators. The possible influencing parameters are reviewed. The determining factor is a too high level of stress arising from two main origins: residual stresses; and overstresses induced by the inner pressure in deformed cross sections. The latter have been assessed by two dimensional finite elements computation and by strain gages measurements. Stress corrosion tests in boiling MgCl2 sustain the previous results for outer surface overstresses. Geometrical characterizations were performed on: in service SG tubes by internal spherical gages; and laboratory samples by internal spherical gages, LVDT and ultrasonic measurements, cross sectioning
Electric dipole moment of diatomic molecules
International Nuclear Information System (INIS)
The calculation of the electric dipole moment of diatomic molecules by the Variational Cellular Method is presented, discussed and compared with the semiempirical CNDO/2 method. The molecule HF is taken as example. It is also shown that the value of the electric dipole moment by the VCM improves considerably when the electronegativity of the atoms of the molecule is taken into account. (Author)
Joint moments of proper delay times
Energy Technology Data Exchange (ETDEWEB)
Martínez-Argüello, Angel M.; Martínez-Mares, Moisés [Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, Apartado Postal 55-534, 09340 México Distrito Federal (Mexico); García, Julio C. [Departamento de Matemáticas, Universidad Autónoma Metropolitana-Iztapalapa, Apartado Postal 55-534, 09340 México Distrito Federal (Mexico)
2014-08-15
We calculate negative moments of the N-dimensional Laguerre distribution for the orthogonal, unitary, and symplectic symmetries. These moments correspond to those of the proper delay times, which are needed to determine the statistical fluctuations of several transport properties through classically chaotic cavities, like quantum dots and microwave cavities with ideal coupling.
A note on noncommutative moment problems
Institute of Scientific and Technical Information of China (English)
MA; Xiujuan
2005-01-01
Noncommutative moment problems for C*-algebras are studied. We generalize a result of Hadwin on tracial states to nontracial case. Our results are applied to obtain simple solutions to moment problems on the square and the circle as well as extend the positive unital functionals from a (discrete) complex group algebra to states on the group C*-algebra.
Learn to Live in the Present Moment
Institute of Scientific and Technical Information of China (English)
贾庆文
2002-01-01
To a large degree, the measure of our peace of mind is determined by how much we are able to live in the present moment. Irrespective of what happened yesterday or last year, and what may or may not happen tomorrow, the present moment is where you are-always!
Teachable Moment: Google Earth Takes Us There
Williams, Ann; Davinroy, Thomas C.
2015-01-01
In the current educational climate, where clearly articulated learning objectives are required, it is clear that the spontaneous teachable moment still has its place. Authors Ann Williams and Thomas Davinroy think that instructors from almost any discipline can employ Google Earth as a tool to take advantage of teachable moments through the…
HELMHOLTZ COILS FOR MEASURING MAGNETIC MOMENTS
Directory of Open Access Journals (Sweden)
P. N. Dobrodeyev
2013-01-01
Full Text Available The optimal configuration of the double Helmholtz coils for measuring of the magnetic dipole moments was defined. It was determined that measuring coils should have round shape and compensative coils – the square one. Analytically confirmed the feasibility of the proposed configuration of these coils as primary transmitters of magnetic dipole moments.
How to Introduce the Magnetic Dipole Moment
Bezerra, M.; Kort-Kamp, W. J. M.; Cougo-Pinto, M. V.; Farina, C.
2012-01-01
We show how the concept of the magnetic dipole moment can be introduced in the same way as the concept of the electric dipole moment in introductory courses on electromagnetism. Considering a localized steady current distribution, we make a Taylor expansion directly in the Biot-Savart law to obtain, explicitly, the dominant contribution of the…
Ruggiero, Matteo Luca
2016-05-01
In the framework of f(T) gravity, we focus on a weak-field and spherically symmetric solution for the Lagrangian f(T) = T + αT2, where α is a small constant which parametrizes the departure from general relativity (GR). In particular, we study the propagation of light and obtain the correction to the general relativistic bending angle. Moreover, we discuss the impact of this correction on some gravitational lensing observables, and evaluate the possibility of constraining the theory parameter α by means of observations. In particular, on taking into account the astrometric accuracy in the Solar System, we obtain that |α|≤ 1.85 × 105m2; this bound is looser than those deriving from the analysis of Solar System dynamics, e.g. |α|≤ 5 × 10‑1m2 [L. Iorio, N. Radicella and M. L. Ruggiero, J. Cosmol. Astropart. Phys. 1508 (2015) 021, arXiv:1505.06996 [gr-qc].], |α|≤ 1.8 × 104m2 [L. Iorio and E. N. Saridakis, Mon. Not. R. Astron. Soc. 427 (2012) 1555, arXiv:1203.5781 [gr-qc].] or |α|≤ 1.2 × 102m2 [Y. Xie and X. M. Deng, Mon. Not. R. Astron. Soc. 433 (2013) 3584, arXiv:1312.4103 [gr-qc].]. However, we suggest that, since the effect only depends on the impact parameter, better constraints could be obtained by studying light bending from planetary objects.
Wigner Distribution Moments Measured as Intensity Moments in Separable First-Order Optical Systems
Directory of Open Access Journals (Sweden)
Tatiana Alieva
2005-06-01
Full Text Available It is shown how all global Wigner distribution moments of arbitrary order can be measured as intensity moments in the output plane of an appropriate number of separable first-order optical systems (generally anamorphic ones. The minimum number of such systems that are needed for the determination of these moments is derived.
On the accuracy of analyses for in-plane bending of smooth pipe bends with end constraints
International Nuclear Information System (INIS)
The accuracy of theoretical analyses for in-plane bending of smooth pipebends with end constraints is discussed and investigated with a view to explaining and reducing the differences between the major works. An earlier theory of the authors is improved to give more accurate answers for bends with rigid flanges. Flanged bends are then examined in some detail, quantifying for the first time the important influence of the flange rigidity on the bend flexibility and stresses. A summary of some finite element analyses is presented from which it is clear that further work is desirable. (orig.)
International Nuclear Information System (INIS)
The influence of the geometry change during creep on the failure life of 90 deg. pipe bends, subjected to internal pressure, was investigated using finite element creep damage analyses. The bends were considered to be circular in shape with no initial ovality. The failure lives obtained using the material properties for a CrMoV pipe steel at 640 deg. C clearly show a significant life reduction when the geometry change is included. In the range of the pipe bend dimension ratios investigated, it was found that the failure lives could be reduced to between 65 and 78% of those obtained from constant geometry cases, indicating that the influence of geometry change may need to be appraised for detailed numerical analysis. The results were compared with those of the corresponding straight pipes and their relevance considered. It has been shown that under constant geometry conditions, the failure life for pipe bends is about 30% lower than that for the straight pipes
International Nuclear Information System (INIS)
The last status report on the non-destructive examination of U-bends removed from Trojan steam generator D was dated July 7, 1980. As part of this activity, the measurement of wall thicknesses on selected U-bends was planned using an ultrasonic gage. These readings were not made because reproducible results could not be obtained using water as the coupling fluid which was necessary to avoid contamination. Three tubes from the same heat were selected for destructive examination at Westinghouse: one leaking U-bend (R1-C6) and two tubes with no indications (R1-C10 and R1-C22). Results of the examination procedure are presented. The non-destructive examination results from the July 7, 1980 report for 29 U-bends are included
Anton, Steven R; Erturk, Alper; Inman, Daniel
2012-06-01
The topic of multifunctional material systems using active or smart materials has recently gained attention in the research community. Multifunctional piezoelectric systems present the ability to combine multiple functions into a single active piezoelectric element, namely, combining sensing, actuation, or energy conversion ability with load-bearing capacity. Quantification of the bending strength of various piezoelectric materials is, therefore, critical in the development of load-bearing piezoelectric systems. Three-point bend tests are carried out on a variety of piezoelectric ceramics including soft monolithic piezoceramics (PZT-5A and PZT-5H), hard monolithic ceramics (PZT-4 and PZT-8), single-crystal piezoelectrics (PMN-PT and PMN-PZT), and commercially packaged composite devices (which contain active PZT-5A layers). A common 3-point bend test procedure is used throughout the experimental tests. The bending strengths of these materials are found using Euler-Bernoulli beam theory to be 44.9 MPa for PMN-PZT, 60.6 MPa for PMN-PT, 114.8 MPa for PZT- 5H, 123.2 MPa for PZT-4, 127.5 MPa for PZT-8, 140.4 MPa for PZT-5A, and 186.6 MPa for the commercial composite. The high strength of the commercial configuration is a result of the composite structure that allows for shear stresses on the surfaces of the piezoelectric layers, whereas the low strength of the single-crystal materials is due to their unique crystal structure, which allows for rapid propagation of cracks initiating at flaw sites. The experimental bending strength results reported, which are linear estimates without nonlinear ferroelastic considerations, are intended for use in the design of multifunctional piezoelectric systems in which the active device is subjected to bending loads. PMID:22711404
Distributed force probe bending model of critical dimension atomic force microscopy bias
Ukraintsev, Vladimir A.; Orji, Ndubuisi G.; Vorburger, Theodore V.; Dixson, Ronald G.; Fu, Joseph; Silver, Rick M.
2013-04-01
Critical dimension atomic force microscopy (CD-AFM) is a widely used reference metrology technique. To characterize modern semiconductor devices, small and flexible probes, often 15 to 20 nm in diameter, are used. Recent studies have reported uncontrolled and significant probe-to-probe bias variation during linewidth and sidewall angle measurements. To understand the source of these variations, tip-sample interactions between high aspect ratio features and small flexible probes, and their influence on measurement bias, should be carefully studied. Using theoretical and experimental procedures, one-dimensional (1-D) and two-dimensional (2-D) models of cylindrical probe bending relevant to carbon nanotube (CNT) AFM probes were developed and tested. An earlier 1-D bending model was refined, and a new 2-D distributed force (DF) model was developed. Contributions from several factors were considered, including: probe misalignment, CNT tip apex diameter variation, probe bending before snapping, and distributed van der Waals-London force. A method for extracting Hamaker probe-surface interaction energy from experimental probe-bending data was developed. Comparison of the new 2-D model with 1-D single point force (SPF) model revealed a difference of about 28% in probe bending. A simple linear relation between biases predicted by the 1-D SPF and 2-D DF models was found. The results suggest that probe bending can be on the order of several nanometers and can partially explain the observed CD-AFM probe-to-probe variation. New 2-D and three-dimensional CD-AFM data analysis software is needed to take full advantage of the new bias correction modeling capabilities.
International Nuclear Information System (INIS)
Highlights: → We proposed the combination rule of multiple cracks as that of multiple flaws. → We proposed additional safety factor for conventional buckling equations. → The margin for the buckling load of a cylinder with multiple flaws is saved 2.0. - Abstract: The procedures described in based on the p-M (internal pressure ratio and external bending moment ratio) method () were used to predict the plastic initiation condition and the collapse condition for cylinders with a local thin area (LTA) subjected to combined internal pressure and bending moment. The effective wall thickness, t*, for the buckling assessment on a vessel with an LTA was proposed for use instead of wall thickness based on approximation which simply took into account only the effect of section modulus reduction (). The buckling evaluation on a vessel with an LTA was presented by and that was shown to be easily and adequately conducted by applying t* to the well-known Donnell's or Miller's equation. In this paper, the attention was focused on the procedure for assessing the buckling of large D/t vessels with multiple aligned or non-aligned local thin areas. From the comparison with the results of non-linear FEA, a combination rule and a buckling assessment procedure for multiple LTAs (flaws) subjected to external moment are proposed. The interaction-affected area for multiple cracks can be applied as the combination rule to evaluate the buckling of a large diameter vessel with multiple flaws subjected to external moment. From the comparison between the buckling loads of FEA results and the conventional buckling equations using the measured yield stress, an additional safety factor 'ks' is proposed so as to maintain the margin of 1.5. When the specified minimum yield stress is applied to Donnell's or Miller's equations, the margin for the buckling load of a cylinder with multiple flaws is more than 2.08 and 2.29, respectively.
Convergence rates in precise asymptotics for a kind of complete moment convergence
Kong, Lingtao; Dai, Hongshuai
2015-01-01
In Liu and Lin (Statist. Probab. Letters, 2006), they introduced a kind of complete moment convergence which includes complete convergence as a special case. Inspired by the study of complete convergence, in this paper, we study the convergence rates of the precise asymptotics for this kind of complete moment convergence and get the corresponding convergence rates.
International Nuclear Information System (INIS)
This paper firstly presents net-section limit moments for circumferential through-wall and part-through surface cracks at the interface between elbows and attached straight pipes under in-plane bending. Closed-form solutions are proposed based on fitting results from small strain FE limit analyses using elastic-perfectly plastic materials. Net-section limit moments for circumferential cracks at the interface between elbows and attached straight pipes are found to be close to those for cracks in the centre of elbows, implying that the location of the circumferential crack within an elbow has a minimal effect on the net-section limit moment. Accordingly it is also found that the assumption that the crack locates in a straight pipe could significantly overestimate the net-section limit load (and thus maximum load-carrying capacity) of the cracked component. Based on the proposed net-section limit moment, a method to estimate elastic-plastic J based on the reference stress approach is proposed for circumferential cracks at the interface between elbows and attached straight pipes under in-plane bending.
Energy Technology Data Exchange (ETDEWEB)
Neki, I.; Tada, T. [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)
1996-12-31
This paper reports a method to develop a new finite element by source (FES) for a two-dimensional plane problem and a three-dimensional solid problem as a method to analyze ship body structures. The paper describes development of a plate bending element by using a similar method, and the fundamental principle thereof. The present method can prepare a finite element of an arbitrary shape by simply providing a contact point only on a boundary. It can also derive good calculation accuracy with less number of contact points and elements. These facts are shown by examples of analyses on a square plate, a triangle plate and a semi-circular plate. Particularly, since a plate bending problem has a large order of differential calculus in a governing equation, this method being a semi-analytical method derives a result with very good accuracy even with less number of contact points. A hypothetical boundary method or a hypothetical electric charge method presents not a very high accuracy even if a large number of contact points are provided. This is because the method hypothesizes only a bending moment vertical to the boundary, but does not consider a source of the moment relative to the boundary. In contrast, the present method hypothesizes both of bending and twisting as the sources, hence its accuracy is better than with the above two methods. 5 refs., 11 figs., 7 tabs.
Regulation of transcription by synthetic DNA-bending agents.
Bednarski, David; Firestine, Steven M
2006-11-01
Gene expression is regulated by a complex interplay between binding and the three-dimensional arrangement of transcription factors with RNA polymerase and DNA. Previous studies have supported a direct role for DNA bending and conformation in gene expression, which suggests that agents that induce bends in DNA might be able to control gene expression. To test this hypothesis, we examined the effect of triple-helix-forming oligonucleotide (TFO) bending agents on the transcription of luciferase in an in vitro transcriptional/translational system. We find that transcription is regulated only by a TFO that induces a bend in the DNA. Related TFOs that do not induce bends in DNA have no effect on transcription. Reporter expression can be increased by as much as 80 % or decreased by as much as 50 % depending on the phasing of the upstream bend relative to the promoter. We interpret the results as follows: when the bend is positioned such that the upstream DNA is curved toward the RNA polymerase on the same DNA face, transcription is enhanced. When the upstream DNA is curved away, transcription is attenuated. These results support the hypothesis that DNA-bending agents might have the capability to regulate gene expression, thereby opening up a previously undervalued avenue in research on the artificial control of gene expression. PMID:17004274
APPLICABILITY OF THE BEND DEVELOPMENT THEORY IN NATURAL ALLUVIAL RIVERS
Institute of Scientific and Technical Information of China (English)
M.M.RAHMAN; M.A.HAQUE; M.M.HOQUE
2002-01-01
The theoretical conditions for the bend development or attenuation have been reviewed and tested for a study reach of the Meghna river.The field observations in the natural alluvial meander do not support the theories developed for bend development.The limitations of the theory to apply in the natural meandering river are discussed.
A numerical investigation of the continuous bending under tension test
Hadoush, A.; Boogaard, van den A.H.; Emmens, W.C.
2011-01-01
In this paper the continuous bending under tension test is analyzed by numerical simulation. The ability of achieving high strains by combined stretching and bending is considered. This deformation mode has similarities with the deformation that takes place in incremental sheet forming (ISF) and may
On Perturbation Solutions for Axisymmetric Bending Boundary Values of a Deep Thin Spherical Shell
Directory of Open Access Journals (Sweden)
Rong Xiao
2014-01-01
Full Text Available On the basis of the general theory of elastic thin shells and the Kirchhoff-Love hypothesis, a fundamental equation for a thin shell under the moment theory is established. In this study, the author derives Reissner’s equation with a transverse shear force Q1 and the displacement component w. These basic unknown quantities are derived considering the axisymmetry of the deep, thin spherical shell and manage to constitute a boundary value question of axisymmetric bending of the deep thin spherical shell under boundary conditions. The asymptotic solution is obtained by the composite expansion method. At the end of this paper, to prove the correctness and accuracy of the derivation, an example is given to compare the numerical solution by ANSYS and the perturbation solution. Meanwhile, the effects of material and geometric parameters on the nonlinear response of axisymmetric deep thin spherical shell under uniform external pressure are also analyzed in this paper.
Sánchez Maciá, Tania
2013-01-01
[SPA]El objetivo de esta tesis es desarrollar nuevas fórmulas empíricas que nos permitan estimar el valor del máximo momento flector en aguas tranquilas para buques de carga autopropulsados de navegación interior. Una fórmula empírica es una expresión derivada sobre la base de los datos experimentales o numérica de los buques. Por lo tanto, este tipo de fórmulas puede proporcionar soluciones razonables para los cascos convencionales, pero no se puede utilizar para los buques...
DEFF Research Database (Denmark)
Andersen, Ingrid Marie Vincent; Jensen, Jørgen Juncher
2012-01-01
the ship. The theory takes into account non-linear radiation forces (memory effects) through the use of a set of higher order differential equations. The non-linear hydrostatic restoring forces and non-linear Froude-Krylov forces are determined accurately at the instantaneous position of the ship in...... statistical analysis is done using the First Order Reliability Method (FORM) supplemented with Monte Carlo simulations. Furthermore, strip-theory calculations are compared to model tests in regular waves of different wave lengths using a segmented, flexible model of the case-ship and good agreement is...
International Nuclear Information System (INIS)
It is necessary to study on the stress concentration experimentally, which is the main reason to avoid mechanical dilapidation and failure, when designing a mechanical structure. Stress concentration factor of a specimen of cantilever beam with a circular hole in the center was measured using both strain gage and photoelastic methods in this paper. In strain-gage measurement, three strain gages along the line near a hole of the specimen were installed and maximum strain was extrapolated from three measurements. In photoelastic measurement, two methods were employed. First, the Babinet-Soleil compensation method was used to measure the maximum strain. Secondly, photoelastic 4-step phase shilling method was applied to observe the strain distribution around the hole. Measurements obtained by different experiments were comparable within the range of experimental error
Table of Nuclear Electric Quadrupole Moments
International Nuclear Information System (INIS)
This Table is a compilation of experimental measurements of static electric quadrupole moments of ground states and excited states of atomic nuclei throughout the periodic table. To aid identification of the states, their excitation energy, half-life, spin and parity are given, along with a brief indication of the method and any reference standard used in the particular measurement. Experimental data from all quadrupole moment measurements actually provide a value of the product of the moment and the electric field gradient [EFG] acting at the nucleus. Knowledge of the EFG is thus necessary to extract the quadrupole moment. A single recommended value of the moment is given for each state, based, for each element, wherever possible, upon a standard reference moment for a nuclear state of that element studied in a situation in which the electric field gradient has been well calculated. For several elements one or more subsidiary reference EFG/moment references are required and their use is specified. The literature search covers the period to mid-2013. (author)
Table of nuclear electric quadrupole moments
Stone, N. J.
2016-09-01
This Table is a compilation of experimental measurements of static electric quadrupole moments of ground states and excited states of atomic nuclei throughout the periodic table. To aid identification of the states, their excitation energy, half-life, spin and parity are given, along with a brief indication of the method and any reference standard used in the particular measurement. Experimental data from all quadrupole moment measurements actually provide a value of the product of the moment and the electric field gradient [EFG] acting at the nucleus. Knowledge of the EFG is thus necessary to extract the quadrupole moment. A single recommended moment value is given for each state, based, for each element, wherever possible, upon a standard reference moment for a nuclear state of that element studied in a situation in which the electric field gradient has been well calculated. For several elements one or more subsidiary EFG/moment reference is required and their use is specified. The literature search covers the period to mid-2015.
Atmospheric Refractive Electromagnetic Wave Bending and Propagation Delay
Mangum, Jeffrey G
2014-01-01
In this tutorial we summarize the physics and mathematics behind refractive electromagnetic wave bending and delay. Refractive bending and delay through the Earth's atmosphere at both radio/millimetric and optical/IR wavelengths are discussed, but with most emphasis on the former, and with Atacama Large Millimeter Array (ALMA) applications in mind. As modern astronomical measurements often require sub-arcsecond position accuracy, care is required when selecting refractive bending and delay algorithms. For the spherically-uniform model atmospheres generally used for all refractive bending and delay algorithms, positional accuracies $\\lesssim 1^{\\prime\\prime}$ are achievable when observing at zenith angles $\\lesssim 75^\\circ$. A number of computationally economical approximate methods for atmospheric refractive bending and delay calculation are presented, appropriate for astronomical observations under these conditions. For observations under more realistic atmospheric conditions, for zenith angles $\\gtrsim 75^...
Revisit the anomalous bending elasticity of sharply bent DNA
Cong, Peiwen; Chen, Hu; van der Maarel, Johan R C; Doyle, Patrick S; Yan, Jie
2015-01-01
Several recent experiments have suggested that sharply bent DNA has a surprisingly high bending flexibility, but the cause is poorly understood. It has been demonstrated that excitation of flexible defects can explain the results; while whether such defects can be excited under the level of DNA bending in those experiments has remained unclear and been debated. Interestingly, due to experimental design DNA contained pre-existing nicks in nearly all those experiments, while the potential effect of nicks have never been considered. Here, using full-atom molecular dynamics (MD) simulations, we show that nicks promote DNA basepair disruption at the nicked sites which drastically reduced DNA bending energy. In the absence of nicks, basepair disruption can also occur, but it requires a higher level of DNA bending. Overall, our results challenge the interpretations of previous sharp DNA bending experiments and highlight that the micromechanics of sharply bent DNA still remains an open question.
Ultimate Bending Capacity of Strain Hardening Steel Pipes
Institute of Scientific and Technical Information of China (English)
陈严飞; 张娟; 张宏; 李昕; 周晶; 曹静
2016-01-01
Based on Hencky’s total strain theory of plasticity, ultimate bending capacity of steel pipes can be determined analytically assuming an elastic-linear strain hardening material, the simplified analytical solution is proposed as well. Good agreement is observed when ultimate bending capacities obtained from analytical solutions are compared with experimental results from full-size tests of steel pipes. Parametric study conducted as part of this paper indicates that the strain hardening effect has significant influence on the ultimate bending capacity of steel pipes. It is shown that pipe considering strain hardening yields higher bending capacity than that of pipe assumed as elastic-perfectly plastic material. Thus, the ignorance of strain hardening effect, as commonly assumed in current codes, may underestimate the ultimate bending capacity of steel pipes. The solutions proposed in this paper are applicable in the design of offshore/onshore steel pipes, supports of offshore platforms and other tubular structural steel members.
Limits of stability in supported graphene nanoribbons subject to bending
Korhonen, Topi; Koskinen, Pekka
2016-06-01
Graphene nanoribbons are prone to in-plane bending even when supported on flat substrates. However, the amount of bending that ribbons can stably withstand remains poorly known. Here, by using molecular dynamics simulations, we study the stability limits of 0.5-1.9-nm-wide armchair and zigzag graphene nanoribbons subject to bending. We observe that the limits for maximum stable curvatures are below ˜10 deg /nm in case the bending is externally forced and the limit is caused by buckling instability. Furthermore, it turns out that the limits for maximum stable curvatures are also below ˜10 deg /nm in case the bending is not forced and the limit arises only from the corrugated potential-energy landscape due to the substrate. Both of the stability limits lower rapidly when ribbons widen. These results agree with recent experiments and can be understood by means of transparent elasticity models.
Bending Modulus Measurement of Single High Performance Fiber
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
The bending modulus property of high performance fiber is an important property for both polymer science and engineering. The measurement of the bending performance is, however, difficult because of the thin size of the fiber. We have measured this property by the axial compression bending method where single fiber with suitable slenderness is compressed in the fiber axial direction to obtain the peak point of the force-displacement curve. Then the bending modulus and the flexural rigidity can be calculated by measuring the protruding length and diameter of fiber needles and the critical force, Pcr. The measured data show that the bending characteristics of all kinds of high performance fiber are dissimilar evidently.
International Nuclear Information System (INIS)
The objective of this study was to investigate the effect of local wall thinning on the collapse behavior of pipe elbows subjected to a combined internal pressure and in-plane bending load. This study evaluated the global deformation behavior and collapse moment of the elbows, which contained various types of local wall-thinning defects at their intrados or extrados, using three-dimensional elastic-plastic finite element analysis. The analysis results showed that the global deformation behavior of locally wall-thinned elbows was largely governed by the mode of the bending and the elbow geometry rather than the wall-thinning parameters, except for elbows with considerably large and deep wall thinning that showed plastic instabilities induced by local buckling and plastic collapsing in the thinned area. The reduction in the collapse moment with wall-thinning depth was considerable when local buckling occurred in the thinned areas, whereas the effect of the thinning depth was small when ovalization occurred. The effects of the circumferential thinning angle and thinning length on the collapse moment of elbows were not major for shallow wall-thinning cases. For deeper wall-thinning cases, however, their effects were significant and the dependence of collapse moment on the axial thinning length was governed by the stress type applied to the wall-thinned area. Typically, the reduction in the collapse moment due to local wall thinning was clearer when the thinning defect was located at the intrados rather than the extrados, and it was apparent for elbows with larger bend radius
Trois moments de la philosophie juive
Directory of Open Access Journals (Sweden)
Stefan Goltzberg
2012-04-01
Full Text Available Je tiens à remercier pour leur relecture attentive : Noémie Benchimol, Shemuel Lampronti et Georges-Elia Sarfati. L’objet de cet article est de suggérer une nouvelle périodisation de la philosophie juive et de mener une réflexion sur la définition de la philosophie juive. Il ne sera donc pas tant question du contenu des philosophies juives, que du style caractérisant chaque philosophie juive. Trois moments de l’histoire de la philosophie juive seront distingués : le moment arabe, le moment al...
The toroid moment of Majorana neutrino
International Nuclear Information System (INIS)
The total set of electromagnetic characteristics of Majorana neutrinos is considered. It is shown that in the static limit (mi=mf=mν) the Majorana neutrinos possess only one electromagnetic characteristic, the toroidal dipole moment (anapole). We have calculated the diagonal toroidal moment (form factor) of the Majorana neutrino in the one-loop approximation of the Standard Model by the dispersion method. All external particles are on the mass shells and there are no problems with the physical interpretation of the final result. Different applications of the toroidal moment of Majorana neutrino are also discussed. 12 refs., 2 figs., 1 tab
Spin and orbital moments in actinide compounds
DEFF Research Database (Denmark)
Lebech, B.; Wulff, M.; Lander, G.H.
1991-01-01
-electron band-structure calculations, is that the orbital moments of the actinide 5f electrons are considerably reduced from the values anticipated by a simple application of Hund's rules. To test these ideas, and thus to obtain a measure of the hybridization, we have performed a series of neutron scattering...... experiments designed to determine the magnetic moments at the actinide and transition-metal sublattice sites in compounds such as UFe2, NpCo2, and PuFe2 and to separate the spin and orbital components at the actinide sites. The results show, indeed, that the ratio of the orbital to spin moment is reduced as...
Moment analysis of hadronic vacuum polarization
International Nuclear Information System (INIS)
I suggest a new approach to the determination of the hadronic vacuum polarization (HVP) contribution to the anomalous magnetic moment of the muon aμHVP in lattice QCD. It is based on properties of the Mellin transform of the hadronic spectral function and their relation to the HVP self-energy in the Euclidean. I show how aμHVP is very well approximated by a few moments associated to this Mellin transform and how these moments can be evaluated in lattice QCD, providing thus a series of tests when compared with the corresponding determinations using experimental data
Institute of Scientific and Technical Information of China (English)
杨骁; 刘鑫
2008-01-01
Based on the mathematical model of the bending of the incompressible saturated poroelastic beam with axialdiffusion, the quasi-static bendings of the simply supported poroelastic beam subjected to a suddenly applied constant loadwere investigated, and the analytical solutions were obtained for different diffusion conditions of the pore fluid at the beamends. The deflections, the bending moments of the solid skeleton and the equivalent couples of the pore pressures werepresented in figures. It is also shown that the behavior of the saturated poroelastic beams depends closely on the diffusionconditions at the beam ends, especially for the equivalent couples of the pore pressures. It is found that the Mandel-Cryereffect also exists in the bending of the saturated poroelastic beams under specific diffusion conditions at the beam ends.
Numerical Investigation of Bending-Body Projectile Aerodynamics for Maneuver Control
Youn, Eric; Silton, Sidra
2015-11-01
Precision munitions are an active area of research for the U.S. Army. Canard-control actuators have historically been the primary mechanism used to maneuver fin-stabilized, gun-launched munitions. Canards are small, fin-like control surfaces mounted at the forward section of the munition to provide the pitching moment necessary to rotate the body in the freestream flow. The additional lift force due to the rotated body and the canards then alters the flight path toward the intended target. As velocity and maneuverability requirements continue to increase, investigation of other maneuver mechanisms becomes necessary. One option for a projectile with a large length-to-diameter ratio (L/D) is a bending-body design, which imparts a curvature to the projectile body along its axis. This investigation uses full Navier-Stokes computational fluid dynamics simulations to evaluate the effectiveness of an 8-degree bent nose tip on an 8-degree bent forward section of an L/D =10 projectile. The aerodynamic control effectiveness of the bending-body concept is compared to that of a standard L/D =10 straight-body projectile as well as that of the same projectile with traditional canards. All simulations were performed at supersonic velocities between Mach 2-4.
Influence of recreational activity and muscle strength on ulnar bending stiffness in men
Myburgh, K. H.; Charette, S.; Zhou, L.; Steele, C. R.; Arnaud, S.; Marcus, R.
1993-01-01
Bone bending stiffness (modulus of elasticity [E] x moment of inertia [I]), a measure of bone strength, is related to its mineral content (BMC) and geometry and may be influenced by exercise. We evaluated the relationship of habitual recreational exercise and muscle strength to ulnar EI, width, and BMC in 51 healthy men, 28-61 yr of age. BMC and width were measured by single photon absorptiometry and EI by mechanical resistance tissue analysis. Maximum biceps strength was determined dynamically (1-RM) and grip strength isometrically. Subjects were classified as sedentary (S) (N = 13), moderately (M) (N = 18), or highly active (H) (N = 20) and exercised 0.2 +/- 0.2; 2.2 +/- 1.3; and 6.8 +/- 2.3 h.wk-1 (P ulnar BMC (P ulnar EI (P = 0.01) than M or S, who were similar. Amount of activity correlated with grip and biceps strength (r = 0.47 and 0.49; P ulnar width (P Ulnar width and biceps strength were the only independent predictors of EI (r2 = 0.67, P ulnar bending stiffness.
Four-Point Bending Strength Testing of Pultruded Fiberglass Composite Wind Turbine Blade Sections
Energy Technology Data Exchange (ETDEWEB)
Musial, W.; Bourne, B; Hughes, S; Zuteck, M. D. (MDZ Consulting)
2001-07-10
The ultimate strength of the PS Enterprises pultruded blade section was experimentally determined under four-point bending at the National Renewable Energy Laboratory. Thirteen 8-foot long full-scale blade segments were individually tested to determine their maximum moment carrying capability. Three airfoil-bending configurations were tested: high- and low-pressure skin buckling, and low pressure skin buckling with foam interior reinforcement. Maximum strain was recorded for each sample on the compressive and tensile surfaces of each test blade. Test data are compared to the results of three analytical buckling prediction methods. Based on deviations from the linear strain versus load curve, data indicate a post-buckling region. High-pressure side buckling occurred sooner than low-pressure side buckling. The buckling analyses were conservative for both configurations, but high-pressure side buckling in particular was substantially under-predicted. Both high- and low-pressure buckling configurations had very similar failure loads. These results suggests that a redundant load path may be providing strength to the section in the post-buckling region, making the onset of panel buckling a poor predictor of ultimate strength for the PS Enterprises pultrusion.
Bending analysis of laminated composite box beams
Energy Technology Data Exchange (ETDEWEB)
Tripathy, A.K.; Patel, H.J.; Pang, S.S. (Louisiana State Univ., Baton Rouge, LA (United States). Dept. of Mechanical Engineering)
1994-01-01
Box beams are widely used in weight reduction structures such as aircraft wings. The use of composite box beams further reduces the weight factor for such structures with the same deflection and stress as that of isotropic box beams. The difference in the behavior of composite box beam with different fiber orientation, number of plies, and number of stringers also provides a wide range of designing parameters to achieve the required performance for a given problem. A bending analysis has been carried out for the study of deflections and stresses for box beams of different material (isotropic and laminated composites), size, and number of stringers subjected to different kinds of loading conditions. A finite element model has been developed based on the strain energy principle, and the results are compared with an available commercial code COSMOS/M.'' Experiments using aluminum and scotchply composite laminates were conducted to verify the results. An optimal design for size and number of stiffeners for a given loading condition has been achieved. Investigations have also been carried out to find the effect of transverse shear on the span-wise normal stress.
Occipital bending (Yakovlevian torque) in bipolar depression.
Maller, Jerome J; Anderson, Rodney; Thomson, Richard H; Rosenfeld, Jeffrey V; Daskalakis, Zafiris J; Fitzgerald, Paul B
2015-01-30
Differing levels of occipital lobe asymmetry and enlarged lateral ventricles have been reported within patients with bipolar disorder (BD) compared with healthy controls, suggesting different rates of occipital bending (OB). This may exert pressure on subcortical structures, such as the hippocampus, reduced among psychiatric patients. We investigated OB prevalence in 35 patients with BD and 36 healthy controls, and ventricular and occipital volumes. Prevalence was four times higher among BD patients (12/35 [34.3%]) than in control subjects (3/36 [8.3%]), as well as larger lateral ventricular volumes (LVVs). Furthermore, we found OB to relate to left-to-right ventricular and occipital lobe volume (OLV) ratios. Those with OB also had reduced left-to-right hippocampal volume ratios. The results suggest that OB is more common among BD patients than healthy subjects, and prevalent in both BD Type I and Type II patients. We posit that anomalies in neural pruning or ventricular enlargement may precipitate OB, consequently resulting in one occipital lobe twisting around the other. Although the clinical implications of these results are unclear, the study suggests that asymmetrical ventricular volume matched with a pattern of oppositely asymmetrical occipital volume is related to OB and may be a marker of psychiatric illness. PMID:25480522
Product Evaluation In Elliptical Helical Pipe Bending
Directory of Open Access Journals (Sweden)
Wasantha Samarathunga
2013-10-01
Full Text Available This research proposes a computation approach to address the evaluation of end product machining accuracy in elliptical surfaced helical pipe bending using 6dof parallel manipulator as a pipe bender. The target end product is wearable metal muscle supporters used in build-to-order welfare product manufacturing. This paper proposes a product testing model that mainly corrects the surface direction estimation errors of existing least squares ellipse fittings, followed by arc length and central angle evaluations. This post-machining modelling requires combination of reverse rotations and translations to a specific location before accuracy evaluation takes place, i.e. the reverse comparing to pre-machining product modelling. This specific location not only allows us to compute surface direction but also the amount of excessive surface twisting as a rotation angle about a specified axis, i.e. quantification of surface torsion. At first we experimented three ellipse fitting methods such as, two least-squares fitting methods with Bookstein constraint and Trace constraint, and one non-linear least squares method using Gauss-newton algorithm. From fitting results, we found that using Trace constraint is more reliable and designed a correction filter for surface torsion observation. Finally we apply 2D total least squares line fitting method with a rectification filter for surface direction detection.
Field measurement for large bending magnets
Energy Technology Data Exchange (ETDEWEB)
Lazzaro, A. [INFN-Laboratori Nazionali del Sud, Via S. Sofia 62, I-95123 Catania (Italy); Cappuzzello, F. [INFN-Laboratori Nazionali del Sud, Via S. Sofia 62, I-95123 Catania (Italy); Dipartimento di Fisica e Astronomia, Universita di Catania, Via S. Sofia 64, I-95123 Catania (Italy)], E-mail: cappuzzello@lns.infn.it; Cunsolo, A.; Cavallaro, M. [INFN-Laboratori Nazionali del Sud, Via S. Sofia 62, I-95123 Catania (Italy); Dipartimento di Fisica e Astronomia, Universita di Catania, Via S. Sofia 64, I-95123 Catania (Italy); Foti, A. [Dipartimento di Fisica e Astronomia, Universita di Catania, Via S. Sofia 64, I-95123 Catania (Italy); INFN-Sezione di Catania, Via S. Sofia 64, I-95123 Catania (Italy); Orrigo, S.E.A.; Rodrigues, M.R.D.; Winfield, J.S. [INFN-Laboratori Nazionali del Sud, Via S. Sofia 62, I-95123 Catania (Italy)
2008-02-01
The results of magnetic field measurements of the large bending magnet of the MAGNEX spectrometer are presented. The experimental values are used to build an Enge function by the least-squares method. The resulting field is compared to the measured one, showing too large deviation for application to ray reconstruction techniques. Similarly, the experimental values are compared with results from a three-dimensional finite elements calculation. Again the deviations between measured and calculated field are too large for a direct application of the latter to ray reconstruction, while its reliability is sufficient for analysis purposes. In particular, it has been applied to study the effect of the inaccuracies in the probe location and orientation on the precision of field reconstruction, and to establish the requirements for the field interpolation. These inaccuracies are found to be rather important, especially for the transversal components of the field, with the consequence that their effect on the reconstructed field should be minimized by special interpolation algorithms.
Moments of the folded logistic distribution
Institute of Scientific and Technical Information of China (English)
Saralees Nadarajah; Samuel Kotz
2007-01-01
The recent paper by Cooray et al. introduced the folded logistic distribution. The moments properties given in the paper appear too complicated. In this note, a simple formula is derived in terms of the well known Lerch function.
Calculation of moments of structure functions
International Nuclear Information System (INIS)
The progress on the lattice computation of low moments of both the unpolarised and polarised nucleon structure functions is reviewed with particular emphasis on continuum and chiral extrapolations and comparison between quenched and unquenched fermions. (orig.)
Magnetic moment of the Roper resonance
Energy Technology Data Exchange (ETDEWEB)
Bauer, T. [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet, D-55099 Mainz (Germany); Gegelia, J., E-mail: gegelia@kph.uni-mainz.de [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet, D-55099 Mainz (Germany); Institut fuer Theoretische Physik II, Ruhr-Universitaet Bochum, 44780 Bochum (Germany); High Energy Physics Institute of TSU, 0186 Tbilisi, Georgia (United States); Scherer, S. [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet, D-55099 Mainz (Germany)
2012-08-29
The magnetic moment of the Roper resonance is calculated in the framework of a low-energy effective field theory of the strong interactions. A systematic power-counting procedure is implemented by applying the complex-mass scheme.
Anomalous magnetic moment with heavy virtual leptons
Energy Technology Data Exchange (ETDEWEB)
Kurz, Alexander [Karlsruher Institut fuer Technologie (Germany). Inst. fuer Theoretische Teilchenphysik; Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Liu, Tao; Steinhauser, Matthias [Karlsruher Institut fuer Technologie (Germany). Inst. fuer Theoretische Teilchenphysik; Marquard, Peter [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)
2013-11-15
We compute the contributions to the electron and muon anomalous magnetic moment induced by heavy leptons up to four-loop order. Asymptotic expansion is applied to obtain three analytic expansion terms which show rapid convergence.
Moments of inertia in a semiclassical approach
International Nuclear Information System (INIS)
Semiclassical calculations have been performed for 31 nuclei. As a result of preliminary non-fully self-consistent calculations, the moments of inertia in investigated nuclei abd spin degrees of freedom are found
Electric dipole moments of fundamental particles
International Nuclear Information System (INIS)
Electric dipole moments (EDM) are at the fore-front of search for physics beyond the standard model. The next generation searches promise to improve by several orders of magnitude the current EDM sensitivity levels
An experimental review of hyperon magnetic moments
International Nuclear Information System (INIS)
Hyperon magnetic moments are important probes for studying the structure of baryons. In this talk, I shall briefly describe how the measurements are made and discuss the current status of the determinations
On recursive relations and moment problems
International Nuclear Information System (INIS)
We investigate in this paper the link between the moment problem for sequences, the associated Jacobi matrices and the Pade approximants of the associated analytic functions. We generalize some classical results by providing simple proofs that use functional calculus. (author)
Magnetic moment of the Roper resonance
Bauer, T.; Gegelia, J.; Scherer, S.
2012-01-01
The magnetic moment of the Roper resonance is calculated in the framework of a low-energy effective field theory of the strong interactions. A systematic power-counting procedure is implemented by applying the complex-mass scheme.
Wavelength Variation Approach in Single Mode-Multimode-Single Mode Optical Fiber as a Bending Sensor
Directory of Open Access Journals (Sweden)
Abdul Samee Khan, Prof. Mohd. Sarwar Raeen
2012-11-01
Full Text Available Multimode interference in optical waveguides has interesting self-imaging properties, which have extensively been investigated and utilized in many integrated optical devices. Multimode interference has also been explored in optical fibers in order to realize fiber devices, including sensors. A basic structure of these devices has been the Single mode –Multimode – Single mode (SMS fiber section concatenation. This dissertation describes theoretical and numerical investigations on multimode interference (MMI devices using a single mode-multimode-single mode (SMS fiber structure for possible use as bending sensor using wavelength variation technique. Several aspects of the SMS edge filters have been investigated, including the effect of bending the SMS fiber cores due to fabrication tolerances, polarization dependence, and temperature dependence. These aspects can impair the performance of a wavelength measurement system. There are several approaches which have been proposed and demonstrated to achieve high resolution and accuracy of wavelength measurement. Bending effects due to the splicing process on the spectral characteristics of SMS fiber structure are investigated experimentally with the help of MATLAB. A limit for the tolerable of the cores of an SMS fiber structure based sensor is proposed, beyond which the fiber spectral performance degrades unacceptably. We use Wavelength variation approach by which we can measure the bending more accurately in optical waveguide, as compare to recent sensors. Due to the power loss the power transmission is decreases and efficiency also reduces. So by wavelength variation approach we developed an efficient spectrometer capable of performing a wide variety of coherent multidimensional measurements at optical wavelengths. In this approach we fixed the power and calculate the variation in the wavelength to sense the bending accurately. We apply our algorithm for performing several comparison
Chung, S M; Yap, A U J; Chandra, S P; Lim, C T
2004-11-15
This study compared two test methods used to evaluate the flexural strength of resin-based dental composites. The two test methods evaluated were the three-point bending test4 and the biaxial flexural test. Materials used in this investigation were from the same manufacturer (3M ESPE) and included microfill (A110), minifill (Z100 and Filtek Z250), polyacid modified (F2000), and flowable [Filtek Flowable (FF)] composites. Flexural strength was determined with the use of both test methods after 1 week of conditioning in water at 37 degrees C. Data were analyzed with the use of an ANOVA/Scheffe test and an independent-samples t test at significance level 0.05. Mean flexural strength (n = 7) ranged from 66.61 to 147.21 and 67.27 to 182.81 MPa for three-point bending and ball-on-three-ball biaxial test methods, respectively. In both test methods, Z100 was significantly stronger than all other composites evaluated. In the three-point bending test, flexural strength of Z250 was significantly higher than A110, F2000 and FF, and FF was significantly stronger than A110 and F2000. The biaxial test method arrived at the same conclusions except that there was no significant difference between Z250 and FF. Pearson's correlation revealed a significantly (p bending test. PMID:15386492
Tube to U-bend support bar in-situ clearance measurement
International Nuclear Information System (INIS)
Most recirculating nuclear steam generators throughout the world have some type of flat bar U-bend restraint or anti-vibration bar for the purpose of positioning the long flexible U-bend tubes in their respective planes. These support bars minimize tube response to flow induced vibration forces and mitigate fretting of tubes due to those forces. Steam generators from all sources have experienced some degree of fretting, usually on a relatively small number of tubes. Flow induced vibration response and fretting are influenced by a large number of parameters including the flow velocity, density, the tube diameter and stiffness, the tube and bar material combination and also the magnitude and consistency of the tube to bar clearances. Over the years the nominal tube to bar support clearances have been systematically reduced. Nevertheless some fretting has still persisted. In pursuing the problem, the expectation is that the situation will be avoided by further reducing nominal clearance. On the other hand, there is little data in hand as to the actual local clearances or the distribution of clearances within a U-bend array. Therefore, it is not possible to ascertain from field data what clearance conditions are necessary for fretting to exist; or more importantly what clearance conditions are necessary to avoid fretting. This paper describes the development for eddy current inspection techniques for in-situ measurement of tube to U-bend support bar clearance. (author)
Link between chips and cutting moments evolution
Cahuc, Olivier; Gérard, Alain; 10.4028/WWW.scientific.net/AMR.423.89
2012-01-01
The better understanding of the material cutting process has been shown with the benefit of the forces and moments measurement since some years ago. In paper, simultaneous six mechanical components and chip orientation measurements were realized during turning tests. During these tests, the influence of the depth of cut or feed rate has been observed and a link between the chip orientation and the moment vector orientation or the central axis characteristics has been shown.
GEL criteria for moment condition models
Smith, Richard J.
2004-01-01
GEL methods which generalize and extend previous contributions are defined and analysed for moment condition models specified in terms of weakly dependent data. These procedures offer alternative one-step estimators and tests that are asymptotically equivalent to their efficient two-step GMM counterparts. The basis for GEL estimation is via a smoothed version of the moment indicators using kernel function weights which incorporate a bandwidth parameter. Examples for the choice of bandwidth pa...
Conditional Moment Models under Weak Identification
Antoine, Bertille; Lavergne, Pascal
2011-01-01
We consider models defined by a set of conditional moment restrictions where weak identification may arise. Weak identification is directly defined through the conditional moments that are allowed to flatten as the sample size increases. We propose a minimum distance estimator of the structural parameters that is robust to potential weak identification and that uses neither instrumental variables nor smoothing. Hence, its properties only depend upon identification weakness, and not on the int...
Affine Moment Invariants Generated by Graph Method
Czech Academy of Sciences Publication Activity Database
Suk, Tomáš; Flusser, Jan
2011-01-01
Roč. 44, č. 9 (2011), 2047 – 2056. ISSN 0031-3203 R&D Projects: GA ČR(CZ) GA102/08/1593 Institutional research plan: CEZ:AV0Z10750506 Keywords : Image moments * Object recognition * Affine transformation * Affine moment invariants * Pseudoinvariants * Graph representation * Irreducibility * Independence Subject RIV: IN - Informatics, Computer Science Impact factor: 2.292, year: 2011 http://library.utia.cas.cz/separaty/2011/ZOI/suk-0359752.pdf
The Moment Guided Monte Carlo Method
Degond, Pierre; Dimarco, Giacomo; Pareschi, Lorenzo
2009-01-01
In this work we propose a new approach for the numerical simulation of kinetic equations through Monte Carlo schemes. We introduce a new technique which permits to reduce the variance of particle methods through a matching with a set of suitable macroscopic moment equations. In order to guarantee that the moment equations provide the correct solutions, they are coupled to the kinetic equation through a non equilibrium term. The basic idea, on which the method relies, consists in guiding the p...
Infrared extrapolations of quadrupole moments and transitions
Odell, D; Platter, L
2015-01-01
We study the convergence of bound-state quadrupole moments in finite harmonic oscillator spaces. We derive an expression for the infrared extrapolation for the quadrupole moment of a nucleus and benchmark our results using different model interactions for the deuteron. We find good agreement between the analytically derived and numerically obtained convergence behavior. We also derive an extrapolation formula for electric quadrupole transitions and find good agreement with the numerical calculation of a simple system.
From moments to functions in quantum chromodynamics
International Nuclear Information System (INIS)
Single-scale quantities, like the QCD anomalous dimensions andWilson coefficients, obey difference equations. Therefore their analytic form can be determined from a finite number of moments. We demonstrate this in an explicit calculation by establishing and solving large scale recursions by means of computer algebra for the anomalous dimensions and Wilson coefficients in unpolarized deeply inelastic scattering from their Mellin moments to 3-loop order. (orig.)
From moments to functions in quantum chromodynamics
Energy Technology Data Exchange (ETDEWEB)
Bluemlein, Johannes; Klein, Sebastian [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Kauers, Manuel; Schneider, Carsten [Johannes Kepler Univ., Linz (Austria). Research Inst. for Symbolic Computation
2009-02-15
Single-scale quantities, like the QCD anomalous dimensions andWilson coefficients, obey difference equations. Therefore their analytic form can be determined from a finite number of moments. We demonstrate this in an explicit calculation by establishing and solving large scale recursions by means of computer algebra for the anomalous dimensions and Wilson coefficients in unpolarized deeply inelastic scattering from their Mellin moments to 3-loop order. (orig.)
PROGRESS IN STUDIES ON ICE ACCUMULATION IN RIVER BENDS
Institute of Scientific and Technical Information of China (English)
WANG Jun; CHEN Pang-pang; SUI Jue-yi
2011-01-01
River ice is an important hydraulic element in temperate and polar environments and would affect hydrodynamic conditions of rivers through changes both in the boundary conditions and the thermal regime.The river bend has been reported as the common location for the initiation of ice jams because the water flow along a river bend is markedly affected by the channel curvature.In this article,the experimental studies about the ice accumulation in a river bend are reviewed.Based on experiments conducted so far,the criteria for the formation of ice jams in the river bend,the mechanisms of the ice accumulation in the river bend and the thickness profile of the ice accumulation in the river bend are discussed.The k- ε two-equation turbulence model is used to simulate the ice accumulation under an ice cover along a river bend.A formula is proposed for describing the deformation of the ice jam bottom.Our results indicate that all simulated thickness of the ice accumulation agrees reasonably well with the measured thickness of the ice accumulation in the laboratory.
Entropy production moment closures and effective transport coefficients
International Nuclear Information System (INIS)
If transport of a given (classical, fermionic, or bosonic) particle species in media is described by a Boltzmann transport equation (BTE), it is often expedient to solve this BTE in the framework of a moment expansion of the particle distribution function, while an exact solution or simulation of the problem with real material properties and complex geometries is unpractical or even unfeasible. Whereas for local thermal equilibrium (LTE) the well-known hydrodynamic equations for the densities of the conserved quantities are derived from the BTE, for non-LTE it is not obvious how to define moments and to close the truncated hierarchy of partial differential equations for these moments. This paper reviews a closure based on entropy production rate minimization, which is applicable to incoherent transport of independent particles in non-LTE interacting with an LTE-medium. The BTE is then linear, includes emission-absorption and elastic scattering processes, and is equivalent to radiative transfer equations. In a large range from diffusive (opaque media) to ballistic (transparent media) transport behaviour, the closure provides useful mean transport coefficients that are exact in the LTE limit, in contrast to the often used maximum entropy moment closure. After an introduction into the underlying theory for massive and wave-like particles, two illustrative examples are discussed. First, the two-moment approximation of radiative heat transfer is reviewed and effective absorption coefficients and the Eddington factor are calculated for a real absorption spectrum. Secondly, the approach is applied to semi-classical electric transport in mesoscopic systems and is shown to provide the correct conductance of a quasi-one-dimensional ballistic conductor with elastic scattering. (topical review)
Entropy production moment closures and effective transport coefficients
Christen, Thomas; Kassubek, Frank
2014-09-01
If transport of a given (classical, fermionic, or bosonic) particle species in media is described by a Boltzmann transport equation (BTE), it is often expedient to solve this BTE in the framework of a moment expansion of the particle distribution function, while an exact solution or simulation of the problem with real material properties and complex geometries is unpractical or even unfeasible. Whereas for local thermal equilibrium (LTE) the well-known hydrodynamic equations for the densities of the conserved quantities are derived from the BTE, for non-LTE it is not obvious how to define moments and to close the truncated hierarchy of partial differential equations for these moments. This paper reviews a closure based on entropy production rate minimization, which is applicable to incoherent transport of independent particles in non-LTE interacting with an LTE-medium. The BTE is then linear, includes emission-absorption and elastic scattering processes, and is equivalent to radiative transfer equations. In a large range from diffusive (opaque media) to ballistic (transparent media) transport behaviour, the closure provides useful mean transport coefficients that are exact in the LTE limit, in contrast to the often used maximum entropy moment closure. After an introduction into the underlying theory for massive and wave-like particles, two illustrative examples are discussed. First, the two-moment approximation of radiative heat transfer is reviewed and effective absorption coefficients and the Eddington factor are calculated for a real absorption spectrum. Secondly, the approach is applied to semi-classical electric transport in mesoscopic systems and is shown to provide the correct conductance of a quasi-one-dimensional ballistic conductor with elastic scattering.
Source-Type Identification Analysis Using Regional Seismic Moment Tensors
Chiang, A.; Dreger, D. S.; Ford, S. R.; Walter, W. R.
2012-12-01
Waveform inversion to determine the seismic moment tensor is a standard approach in determining the source mechanism of natural and manmade seismicity, and may be used to identify, or discriminate different types of seismic sources. The successful applications of the regional moment tensor method at the Nevada Test Site (NTS) and the 2006 and 2009 North Korean nuclear tests (Ford et al., 2009a, 2009b, 2010) show that the method is robust and capable for source-type discrimination at regional distances. The well-separated populations of explosions, earthquakes and collapses on a Hudson et al., (1989) source-type diagram enables source-type discrimination; however the question remains whether or not the separation of events is universal in other regions, where we have limited station coverage and knowledge of Earth structure. Ford et al., (2012) have shown that combining regional waveform data and P-wave first motions removes the CLVD-isotropic tradeoff and uniquely discriminating the 2009 North Korean test as an explosion. Therefore, including additional constraints from regional and teleseismic P-wave first motions enables source-type discrimination at regions with limited station coverage. We present moment tensor analysis of earthquakes and explosions (M6) from Lop Nor and Semipalatinsk test sites for station paths crossing Kazakhstan and Western China. We also present analyses of smaller events from industrial sites. In these sparse coverage situations we combine regional long-period waveforms, and high-frequency P-wave polarity from the same stations, as well as from teleseismic arrays to constrain the source type. Discrimination capability with respect to velocity model and station coverage is examined, and additionally we investigate the velocity model dependence of vanishing free-surface traction effects on seismic moment tensor inversion of shallow sources and recovery of explosive scalar moment. Our synthetic data tests indicate that biases in scalar
Response of Flexible Risers in Bend Stiffener Area
Løseth, Kim
2011-01-01
Flexible risers is a vital part of a floating production system (FPS). In order to predict the riser life time, many procedure may be applied. In this thesis it is assumed that the pipe could be represented with help of performing two sets of global anlayis. Where in the first set it is assumed that the bending stiffness of the pipe is similar to the stick region of the flexible pipe and in the second part the bending stiffness it is assumed a bending stiffness similar to the slip regime of t...
Response of Flexible Risers in Bend Stiffener Area
Løseth, Kim
2011-01-01
Flexible risers is a vital part of a floating production system (FPS). In order to predict the riser life time, many procedure may be applied.In this thesis it is assumed that the pipe could be represented with help of performing two sets of global anlayis. Where in the first set it is assumed that the bending stiffness of the pipe is similar to the stick region of the flexible pipe and in the second part the bending stiffness it is assumed a bending stiffness similar to the slip regime of th...
Investigation of ion induced bending mechanism for nanostructures
International Nuclear Information System (INIS)
Ion induced bending is a promising controlled technique for manipulating nanoscale structures. However, the underlying mechanism of the process is not well understood. In this letter, we report a detailed study of the bending mechanism of Si nanowires (NWs) under Ga+ irradiation. The microstructural changes in the NW due to ion beam irradiation are studied and molecular dynamics simulations are used to explore the ion–NW interaction processes. The simulation results are compared with the microstructural studies of the NW. The investigations inform a generic understanding of the bending process in crystalline materials, which we suggest to be feasible as a versatile manipulation and integration technique in nanotechnology. (paper)
Influence of plywood grain direction on sandwich panel bending properties
Jaroslav Kljak; Mladen Brezović; Alan Antonović
2009-01-01
This paper investigates the influence of plywood grain direction on bending properties of a sandwich panel, as well as on stress distribution in each layer. Experimental sandwich panels (tnom= 29 mm) were made of two three-ply plywood panels and a rigid PVC core between them. Grain directions of plywood panels were between 0° and 90°, continuously raised by 15°. Seven models of sandwich panels were made. Bending properties of a sandwich panel was determined by three point bending method and s...
Localized bending fatigue behavior of high-strength steel monostrands
DEFF Research Database (Denmark)
Winkler, Jan; Fischer, Gregor; Georgakis, Christos T.
2012-01-01
strain distribution in the strand and helps in identifying potential failure mechanisms along the strand and at the wedge location. Initial analysis of the deformations shows that the bending fatigue behavior of the monostrand may be controlled either by local bending deformations or by relative......In this paper, the localized bending fatigue behavior of pretensioned high strength steel monostrands is investigated. Furthermore, a new methodology using an optical photogrammetry system, which can quantify surface deformations on the strand is presented. The system allows measurement of the...
Bertolotto, Jorge A.; Umazano, Juan P.
2016-06-01
In the present work we make a theoretical study of the steady state electric linear dichroism of DNA fragments in aqueous solution. The here developed theoretical approach considers a flexible bent rod model with a saturating induced dipole moment. The electric polarizability tensor of bent DNA fragments is calculated considering a phenomenological model which theoretical and experimental backgroung is presented here. The model has into account the electric polarizability longitudinal and transversal to the macroion. Molecular flexibility is described using an elastic potential. We consider DNA fragments originally bent with bending fluctuations around an average bending angle. The induced dipole moment is supposed constant once the electric field strength grows up at critical value. To calculate the reduced electric linear dichroism we determine the optical factor considering the basis of the bent DNA perpendicular to the molecular axis. The orientational distribution function has into account the anisotropic electric properties and the molecule flexibility. We applied the present theoretical background to fit electric dichroism experimental data of DNA fragments reported in the bibliography in a wide range of molecular weight and electric field. From these fits, values of DNA physical properties are estimated. We compare and discuss the results here obtained with the theoretical and experimental data presented by other authors. The original contributions of this work are: the inclusion of the transversal electric polarizability saturating with the electric field, the description of the electric properties with an electric polarizability tensor dependant on the bending angle and the use of an arc model originally bent.
Bradfield, C A; Demetropoulos, C K; Luongo, M E; Pyles, C O; Armiger, R S; Merkle, A C
2015-01-01
Underbody blast (UBB) events transmit high-rate vertical loads through the seated occupants lumbar spine and have a high probability of inducing severe injury. While previous studies have characterized the lumbar spine under quasi-static loading, additional work should focus on the complex kinetic and kinematic response under high loading rates. To discern the biomechanical influence of the lumbar spines anatomical structures during dynamic loading, the axial force, flexion-extension moments and range of motion for lumbar motion segments (n=18) were measured during different states of progressive dissection. Pre-compression was applied using a static mass while dynamic bending was applied using an offset drop mass. Dynamic loading resulted in peak axial loads of 4,224±133 N, while maximum peak extension and flexion moments were 19.6±12.5 and -44.8±8.6 Nm in the pre-dissected state, respectively. Upon dissection, transection of the interspinous ligament, ligamentum flavum and facet capsules resulted in significantly larger flexion angles, while the removal of the posterior elements increased the total peak angular displacement in extension from 3.3±1.5 to 5.0±1.7 degrees (p=0.002). This study provides insight on the contribution of individual anatomical components on overall lumbar response under high-rate loading, as well as validation data for numerical models. PMID:25996712
Continuous time random walk: Galilei invariance and relation for the nth moment
International Nuclear Information System (INIS)
We consider a decoupled continuous time random walk model with a generic waiting time probability density function (PDF). For the force-free case we derive an integro-differential diffusion equation which is related to the Galilei invariance for the probability density. We also derive a general relation which connects the nth moment in the presence of any external force to the second moment without external force, i.e. it is valid for any waiting time PDF. This general relation includes the generalized second Einstein relation, which connects the first moment in the presence of any external force to the second moment without any external force. These expressions for the first two moments are verified by using several kinds of the waiting time PDF. Moreover, we present new anomalous diffusion behaviours for a waiting time PDF given by a product of power-law and exponential function.
Strange Quark Magnetic Moment of the Nucleon at Physical Point
Sufian, Raza Sabbir; Alexandru, Andrei; Draper, Terrence; Liu, Keh-Fei; Liang, Jian
2016-01-01
We report a lattice QCD calculation of the strange quark contribution to the proton's magnetic moment and charge radius. This analysis presents the first direct determination of strange electromagnetic form factors including the physical pion mass with chiral fermions. We perform a model-independent extraction of the strange magnetic moment and the strange charge radius from the electromagnetic form factors in the momentum transfer range of $0.051 \\,\\text{GeV}^2 \\lesssim Q^2 \\lesssim 1.31 \\,\\text{GeV}^2 $. The finite lattice spacing and finite volume corrections are included in a global fitting with $17$ valence quark masses on three lattices with different lattice spacings, different volumes, and three sea quark masses including one at the physical pion mass. We obtain the strange magnetic moment $G^s_M(0) = - 0.073(17)(08)\\, \\mu_N$. The 4-sigma precision in statistics is achieved partly due to the low-mode averaging of the quark loop and low-mode substitution of the nucleon source to improve the statistics ...
Advantages of customer/supplier involvement in the upgrade of River Bend`s IST program
Energy Technology Data Exchange (ETDEWEB)
Womack, R.L.; Addison, J.A.
1996-12-01
At River Bend Station, IST testing had problems. Operations could not perform the test with the required repeatability; engineering could not reliably trend test data to detect degradation; licensing was heavily burdened with regulatory concerns; and maintenance could not do preventative maintenance because of poor prediction of system health status. Using Energy`s Total Quality principles, it was determined that the causes were: lack of ownership, inadequate test equipment usage, lack of adequate procedures, and lack of program maintenance. After identifying the customers and suppliers of the IST program data, Energy management put together an upgrade team to address these concerns. These customers and suppliers made up the IST upgrade team. The team`s mission was to supply River Bend with a reliable, functional, industry correct and user friendly IST program. The IST program in place went through a verification process that identified and corrected over 400 individual program discrepancies. Over 200 components were identified for improved testing methods. An IST basis document was developed. The operations department was trained on ASME Section XI testing. All IST tests have been simplified and shortened, due to heavy involvement by operations in the procedure development process. This significantly reduced testing time, resulting in lower cost, less dose and greater system availability.
Preliminary Project Investigation : Holla Bend National Wildlife Refuge
US Fish and Wildlife Service, Department of the Interior — This report covers the proposed expansion of Holla Bend National Wildlife Refuge to increase the quantity and quality of wintering habitat primarily for mallards...
NUMERICAL INVESTIGATION ON FLOW CHARACTERISTICS IN RIBBED BEND
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
Previous research［1］by the author has proved that ribbed bend technology is a simple and efficient anti-erosion method. The present paper is a further study to unveil the mechanism of the technology by using numerical method. The flow characteristics in ribbed bend were studied. A k-ε turbulence model was used and the simulations were carried out in the body-fitted coordinates. This procedure was confirmed to be credible by showing the satisfactory agreement between the predications and experimental results. It is concluded that the character of the longitudinal flow in ribbed bend especially in the concave parts between ribs has a beneficial effect on increasing the anti-erosion ability of ribbed bend but the secondary flow will have little effect on determining the particle trajectory.
Holla Bend National Wildlife Refuge: Comprehensive Conservation Plan
US Fish and Wildlife Service, Department of the Interior — This Comprehensive Conservation Plan (CCP) was written to guide management on Holla Bend NWR for the next 15 years. This plan outlines the Refuge vision and purpose...
Fishery Manangement Plan : Holla Bend National Wildlife Refuge
US Fish and Wildlife Service, Department of the Interior — This plan describes fishery management for Holla Bend National Wildlife Refuge in 1990. The plan outlines goals, objectives for fishery management for the benefit...
Computational Strategies for the Architectural Design of Bending Active Structures
DEFF Research Database (Denmark)
Tamke, Martin; Nicholas, Paul
2013-01-01
stiffness, it is possible to control and pre-calibrate the bending behaviour of a composite element. This material capacity challenges architecture’s existing methods for design, specification and prediction. In this paper, we demonstrate how architects might connect the designed nature of composites with...... the design of bending-active structures, through computational strategies. We report three built structures that develop architecturally oriented design methods for bending-active systems using composite materials. These projects demonstrate the application and limits of the introduction of advanced......Active bending introduces a new level of integration into the design of architectural structures, and opens up new complexities for the architectural design process. In particular, the introduction of material variation reconfigures the design space. Through the precise specification of their...
Technique cuts time and cost of bending jacketed piping
Gardner, J. N.
1967-01-01
Technique uses a stiff medium in the annular space between inner and outer pipes of jacketed piping in transfer lines. The process eliminates splitting and welding and makes possible the use of standard pipe-bending tools.
Cylindrical Bending of Deformable Textile Rectangular Patch Antennas
Freek Boeykens; Hendrik Rogier; Luigi Vallozzi
2012-01-01
Textile patch antennas are well known as basic components for wearable systems that allow communication between a human body and the external world. Due to their flexibility, textile antennas are subjected to bending when worn, causing a variation in resonance frequency and radiation pattern with respect to the flat state in which their nominal design is performed. Hence, it is important for textile antenna engineers to be able to predict these performance parameters as a function of the bend...
Species-specific patterns of DNA bending and sequence.
VanWye, J D; Bronson, E C; Anderson, J N
1991-01-01
Nucleotide sequences in the GenEMBL database were analyzed using strategies designed to reveal species-specific patterns of DNA bending and DNA sequence. The results uncovered striking species-dependent patterns of bending with more variations among individual organisms than between prokaryotes and eukaryotes. The frequency of bent sites in sequences from different bacteria was related to genomic A + T content and this relationship was confirmed by electrophoretic analysis of genomic DNA. How...
Theory of bending waves with applications to disk galaxies
Energy Technology Data Exchange (ETDEWEB)
Mark, J.W.K.
1982-01-01
A theory of bending waves is surveyed which provides an explanation for the required amplification of the warp in the Milky Way. It also provides for self-generated warps in isolated external galaxies. The shape of observed warps and partly their existence in isolated galaxies are indicative of substantial spheroidal components. The theory also provides a plausible explanation for the bending of the inner disk (<2 kpc) of the Milky Way.
Theory of bending waves with applications to disk galaxies
International Nuclear Information System (INIS)
A theory of bending waves is surveyed which provides an explanation for the required amplification of the warp in the Milky Way. It also provides for self-generated warps in isolated external galaxies. The shape of observed warps and partly their existence in isolated galaxies are indicative of substantial spheroidal components. The theory also provides a plausible explanation for the bending of the inner disk (<2 kpc) of the Milky Way
Dynamics of fast charged particle beam rotation in bended crystals
International Nuclear Information System (INIS)
Dynamics of fast charged particle beam rotation in a bended monocrystal is considered. Face and volume mechanisms of capture in channels are taken into account simultaneously in the model presented. Functions of distribution in transverse energies (φ) of channeled and dechanneled particles are obtained. Charge-energy ''scale invariance'' in ion channeling with charge Z in a bended crystal determined by scale parameter W=pv/Z (p and v are pulse and velocity local to transverse planes) follows from the model presented
Geometric structures on moment-angle manifolds
International Nuclear Information System (INIS)
A moment-angle complex ZK is a cell complex with a torus action constructed from a finite simplicial complex K. When this construction is applied to a triangulated sphere K or, in particular, to the boundary of a simplicial polytope, the result is a manifold. Moment-angle manifolds and complexes are central objects in toric topology, and currently are gaining much interest in homotopy theory and complex and symplectic geometry. The geometric aspects of the theory of moment-angle complexes are the main theme of this survey. Constructions of non-Kähler complex-analytic structures on moment-angle manifolds corresponding to polytopes and complete simplicial fans are reviewed, and invariants of these structures such as the Hodge numbers and Dolbeault cohomology rings are described. Symplectic and Lagrangian aspects of the theory are also of considerable interest. Moment-angle manifolds appear as level sets for quadratic Hamiltonians of torus actions, and can be used to construct new families of Hamiltonian-minimal Lagrangian submanifolds in a complex space, complex projective space, or toric varieties. Bibliography: 59 titles
Steiner, Oliver; Coisne, Caroline; Engelhardt, Britta; Lyck, Ruth
2010-01-01
Important insights into the molecular mechanism of T cell extravasation across the blood–brain barrier (BBB) have already been obtained using immortalized mouse brain endothelioma cell lines (bEnd). However, compared with bEnd, primary brain endothelial cells have been shown to establish better barrier characteristics, including complex tight junctions and low permeability. In this study, we asked whether bEnd5 and primary mouse brain microvascular endothelial cells (pMBMECs) were equally sui...
Power monitor miter bends for high-power microwave transmission
Energy Technology Data Exchange (ETDEWEB)
Doane, John, E-mail: doane@fusion.gat.com; Anderson, James; Grunloh, Howard; Wu, Wen
2015-04-15
Two miter bends are described for monitoring the power transmitted in an oversized corrugated wave-guide. One has an array of holes in its mirror that couples a small fraction of the incident power to a rectangular waveguide directly machined into the mirror. Millimeter-wave detectors on the outputs of this miter bend can respond very rapidly to the transmitted power, but the coupling is sensitive to the mode purity in the oversized waveguide. The other miter bend monitors the power by measuring the rise in temperature of the cooling water passing through the mirror. The mirror is well isolated from the miter bend housing to prevent heat from neighboring waveguides from reaching the mirror. The measurement requires about 200 s to reach steady state, but it is relatively insensitive to mode purity. The measurement does require knowledge of the input polarization. Thermo-mechanical analyses of the miter bends indicate that they are capable of reliable operation with 1.5 MW transmitted through them. High-power long-pulse 170 GHz tests of these miter bends at the Japan Atomic Energy Agency (JAEA) are described.
Influence of plywood grain direction on sandwich panel bending properties
Directory of Open Access Journals (Sweden)
Jaroslav Kljak
2009-06-01
Full Text Available This paper investigates the influence of plywood grain direction on bending properties of a sandwich panel, as well as on stress distribution in each layer. Experimental sandwich panels (tnom= 29 mm were made of two three-ply plywood panels and a rigid PVC core between them. Grain directions of plywood panels were between 0° and 90°, continuously raised by 15°. Seven models of sandwich panels were made. Bending properties of a sandwich panel was determined by three point bending method and stress in each layer was determined by using finite element method. Simulation models were developed with equal load conditions as applied during empirical measurement of bending properties of the sandwich panel. The research results show that grain direction has a great influence on bending properties of the sandwich panel, as well as on stress values in each layer. Results also indicate the importance of analyzing stress in each layer of plywood for the purpose of avoiding stress concentration in respective layers and for optimizing structural construction of the sandwich panel. Such stress analyses are not covered by standardized empirical methods for determining bending properties of sandwich panels.
Tunable characteristics of bending resonance frequency in magnetoelectric laminated composites
Chen, Lei; Li, Ping; Wen, Yu-Mei; Zhu, Yong
2013-07-01
As the magnetoelectric (ME) effect in piezoelectric/magnetostrictive laminated composites is mediated by mechanical deformation, the ME effect is significantly enhanced in the vicinity of resonance frequency. The bending resonance frequency (fr) of bilayered Terfenol-D/PZT (MP) laminated composites is studied, and our analysis predicts that (i) the bending resonance frequency of an MP laminated composite can be tuned by an applied dc magnetic bias (Hdc) due to the ΔE effect; (ii) the bending resonance frequency of the MP laminated composite can be controlled by incorporating FeCuNbSiB layers with different thicknesses. The experimental results show that with Hdc increasing from 0 Oe (1 Oe=79.5775 A/m) to 700 Oe, the bending resonance frequency can be shifted in a range of 32.68 kHz bending resonance frequency of the MP laminated composite gradually increases from 33.66 kHz to 39.18 kHz. This study offers a method of adjusting the strength of dc magnetic bias or the thicknesses of the FeCuNbSiB layer to tune the bending resonance frequency for ME composite, which plays a guiding role in the ME composite design for real applications.
Tunable characteristics of bending resonance frequency in magnetoelectric laminated composites
Institute of Scientific and Technical Information of China (English)
Chen Lei; Li Ping; Wen Yu-Mei; Zhu Yong
2013-01-01
As the magnetoelectric (ME) effect in piezoelectric/magnetostrictive laminated composites is mediated by mechanical deformation,the ME effect is significantly enhanced in the vicinity of resonance frequency.The bending resonance frequency (fr) of bilayered Terfenol-D/PZT (MP) laminated composites is studied,and our analysis predicts that (i) the bending resonance frequency of an MP laminated composite can be tuned by an applied dc magnetic bias (Hdc) due to the △E effect; (ii) the bending resonance frequency of the MP laminated composite can be controlled by incorporating FeCuNbSiB layers with different thicknesses.The experimental results show that with Hdc increasing from 0Oe (1 Oe=79.5775 A/m)to 700 Oe,the bending resonance frequency can be shifted in a range of 32.68 kHz ≤ fr ≤ 33.96 kHz.In addition,with the thickness of the FeCuNbSiB layer increasing from 0 μm to 90 μm,the bending resonance frequency of the MP laminated composite gradually increases from 33.66 kHz to 39.18 kHz.This study offers a method of adjusting the strength of dc magnetic bias or the thicknesses of the FeCuNbSiB layer to tune the bending resonance frequency for ME composite,which plays a guiding role in the ME composite design for real applications.
Optimal Orthogonal Graph Drawing with Convex Bend Costs
Bläsius, Thomas; Wagner, Dorothea
2012-01-01
Traditionally, the quality of orthogonal planar drawings is quantified by either the total number of bends, or the maximum number of bends per edge. However, this neglects that in typical applications, edges have varying importance. Moreover, as bend minimization over all planar embeddings is NP-hard, most approaches focus on a fixed planar embedding. We consider the problem OptimalFlexDraw that is defined as follows. Given a planar graph G on n vertices with maximum degree 4 and for each edge e a cost function cost_e : N_0 --> R defining costs depending on the number of bends on e, compute an orthogonal drawing of G of minimum cost. Note that this optimizes over all planar embeddings of the input graphs, and the cost functions allow fine-grained control on the bends of edges. In this generality OptimalFlexDraw is NP-hard. We show that it can be solved efficiently if 1) the cost function of each edge is convex and 2) the first bend on each edge does not cause any cost (which is a condition similar to the posi...
Conservative Moment Equations for Neutrino Radiation Transport with Limited Relativity
Endeve, Eirik; Mezzacappa, Anthony
2012-01-01
We derive conservative, multidimensional, energy-dependent moment equations for neutrino transport in core-collapse supernovae and related astrophysical systems, with particular attention to the consistency of conservative four-momentum and lepton number transport equations. After taking angular moments of conservative formulations of the general relativistic Boltzmann equation, we specialize to a conformally flat spacetime, which also serves as the basis for four further limits. Two of these---the multidimensional special relativistic case, and a conformally flat formulation of the spherically symmetric general relativistic case---are given in appendices for the sake of comparison with extant literature. The third limit is a weak-field, `pseudo-Newtonian' approach \\citep{kim_etal_2009,kim_etal_2012} in which the source of the gravitational potential includes the trace of the stress-energy tensor (rather than just the mass density), and all orders in fluid velocity $v$ are retained. Our primary interest here ...
Magnetic moments of odd-odd spherical nuclei
Achakovskiy, O I; Saperstein, E E; Tolokonnikov, S V
2013-01-01
Magnetic moments of more than one hundred odd-odd spherical nuclei in ground and excited states are calculated within the self-consistent TFFS based on the EDF method by Fayans {\\it et al}. We limit ourselves to nuclei with a neutron and a proton particle (hole) added to the magic or semimagic core. A simple model of no interaction between the odd nucleons is used. In most the cases we analyzed, a good agreement with the experimental data is obtained. Several cases are considered where this simple model does not work and it is necessary to go beyond. The unknown values of magnetic moments of many unstable odd and odd-odd nuclei are predicted including sixty values for excited odd-odd nuclei.
Ground-State Electromagnetic Moments of Calcium Isotopes
Ruiz, R F Garcia; Blaum, K; Frommgen, N; Hammen, M; Holt, J D; Kowalska, M; Kreim, K; Menendez, J; Neugart, R; Neyens, G; Nortershauser, W; Nowacki, F; Papuga, J; Poves, A; Schwenk, A; Simonis, J; Yordanov, D T
2015-01-01
High-resolution bunched-beam collinear laser spectroscopy was used to measure the optical hyperfine spectra of the $^{43-51}$Ca isotopes. The ground state magnetic moments of $^{49,51}$Ca and quadrupole moments of $^{47,49,51}$Ca were measured for the first time, and the $^{51}$Ca ground state spin $I=3/2$ was determined in a model-independent way. Our results provide a critical test of modern nuclear theories based on shell-model calculations using phenomenological as well as microscopic interactions. The results for the neutron-rich isotopes are in excellent agreement with predictions using interactions derived from chiral effective field theory including three-nucleon forces, while lighter isotopes illustrate the presence of particle-hole excitations of the $^{40}$Ca core in their ground state.
Constraining neutrino magnetic moment with solar neutrino data
Tortola, M A
2003-01-01
We use solar neutrino data to derive stringent bounds on Majorana neutrino transition moments (TMs). Such moments, if present, would contribute to the neutrino-electron scattering cross section and hence alter the signal observed in Super-Kamiokande. Using the latest solar neutrino data, combined with the results of the reactor experiment KamLAND, we perform a simultaneous fit of the oscillation parameters and TMs. Furthermore, we include data from the reactor experiments Rovno, TEXONO and MUNU in our analysis, improving significantly the current constraints on TMs. A comparison with previous works shows that our bounds are the strongest and most general results presented up to now. Finally, we perform a simulation of the future Borexino experiment and show that it will improve the bounds from today's data by order of magnitude.