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...
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
Influence of Whipping on Long term Vertical Bending Moment
DEFF Research Database (Denmark)
Baarholm, G. S.; Jensen, Jørgen Juncher
2004-01-01
This paper is concerned with estimating the response value corresponding to a long return period, say a twenty years. Time domain simulation is required to obtain the nonlinear response, and long time series are required to limit the statistical uncertainty in the simulations. It is crucial to in......). Results are presented for the S-175 container ship, (15th & 16th ITTC Seakeeping Committee 1983). The analysis shoes that whipping increases the vertical bending moment and that the correlation is significant...
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
Estimation of Ship Long-term Wave-induced Bending Moment using Closed-Form Expressions
DEFF Research Database (Denmark)
Jensen, Jørgen Juncher; Mansour, A. E.
2002-01-01
A semi-analytical approach is used to derive frequency response functions and standard deviations for the wave-induced bending moment amidships for mono-hull ships. The results are given as closed-form expressions and the required input information for the procedure is restricted to the main...... dimensions: Length, breadth, draught, block coefficient and bow flare coefficient, speed and heading, and the sea state parameters HS and TZ. Extreme value predictions are performed based on a user-defined operational profile and takes into account non-linearities due to bow flare using a semi......-empirical closed-form expression for the skewness. The effect of whipping is included by assuming that whipping and wave-induced responses are conditionally independent given Hs. The procedure is simple and can be used to make quick estimates of the design wave bending moment at the conceptual design phase...
Bending Moment Calculations for Piles Based on the Finite Element Method
Directory of Open Access Journals (Sweden)
Yu-xin Jie
2013-01-01
Full Text Available Using the finite element analysis program ABAQUS, a series of calculations on a cantilever beam, pile, and sheet pile wall were made to investigate the bending moment computational methods. The analyses demonstrated that the shear locking is not significant for the passive pile embedded in soil. Therefore, higher-order elements are not always necessary in the computation. The number of grids across the pile section is important for bending moment calculated with stress and less significant for that calculated with displacement. Although computing bending moment with displacement requires fewer grid numbers across the pile section, it sometimes results in variation of the results. For displacement calculation, a pile row can be suitably represented by an equivalent sheet pile wall, whereas the resulting bending moments may be different. Calculated results of bending moment may differ greatly with different grid partitions and computational methods. Therefore, a comparison of results is necessary when performing the analysis.
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.
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.
Strength performance of mortise and loose-tenon furniture joints under uniaxial bending moment
Institute of Scientific and Technical Information of China (English)
Mohammad Derikvand; Ghanbar Ebrahimi
2014-01-01
We determined the effects of adhesive type and loose tenon dimensions (length and thickness) on bending strength of T-shaped mor-tise and loose-tenon joints. Polyvinyl acetate (PVAc) and two-component polyurethane (PU) adhesives were used to construct joint specimens. The bending moment capacity of joints increased significantly with increased length and thickness of the loose tenon. Bending moment capacity of joints constructed with PU adhesive was approximately 13%higher than for joints constructed with PVAc adhesive. We developed a predictive equation as a function of adhesive type and loose tenon dimensions to estimate the strength of the joints constructed of oriental beech (Fagus orientalis L.) under uniaxial bending load.
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.
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...
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...
On the Effect of Green Water on Deck on the Wave Bending Moment
DEFF Research Database (Denmark)
Wang, Zhaohui; Jensen, Jørgen Juncher; Xia, Jinzhu
1998-01-01
and a momentum term, using an effective relative motion calibrated with the model tests, model the green water load. The resulting loads are of the same magnitude as the slamming loads. The results show only a marginal influence of the green water load on the maximum wave bending moment, although the time signal...
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.
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...
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
DEFF Research Database (Denmark)
Poulios, Konstantinos; Niordson, Christian Frithiof
2016-01-01
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......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...... of the matrix and the fibers....
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.
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.
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
Determine Bending Moment of Plane Bending Beam by Graphical Method%用图解法确定平面弯曲梁的弯矩
Institute of Scientific and Technical Information of China (English)
闫志琴
2014-01-01
针对传统“解析法”的弊端，利用剪力图中剪力所围区域面积的代数量与弯矩图中的弯矩代数量间存在一一对应关系的特点，采用“图解法”介绍了求解、校核平面弯曲梁强度和刚度的核心内容———弯矩值，凸显了图解法快速、准确、易学、深刻记忆的优点。%Aiming at shortcomings of conventional analytical method and utilizing the characteristic of the one to one correspon‐dence between the algebra of area surrounding by shearing force and algebra of bending moment in bending moment diagram ,in this paper ,we introduced the utilization of graphical method to solve and check bending moment value which is the core contents of intensity and rigidity of plane bending beam .Our graphical method highlights the advantage of the novel method:rapidity ,ac‐curacy ,learnability ,and profound memory .
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.
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
Institute of Scientific and Technical Information of China (English)
Daien Shi; Ziqi Cai; Archie Eaglesham; Zhengming Gao
2015-01-01
The bending moment acting on the overhung shaft of a gas-sparged vessel stirred by a Rushton turbine, as one of the results of fluid and structure interactions in stirred vessels, was measured using a moment sensor equipped with digital telemetry. An analysis of the shaft bending moment amplitude shows that the amplitude distribution of the bending moment, which indicates the elasticity nature of shaft material against bending deformation, fol-lows the Weibull distribution. The trends of amplitude mean, standard deviation and peak deviation character-istics manifest an“S”shape versus gas flow. The“S”trend of the relative mean bending moment over gas flow rate, depending on the flow regime in gas–liquid stirred vessels, resulted from the competition among the non-uniformity of bubbly flow around the impeller, the formation of gas cavities behind the blades, and the gas direct impact on the impel er when gas is introduced. A further analysis of the bending moment power spectral density shows that the rather low frequency and speed frequency are evident. The low-frequency contribution to bend-ing moment fluctuation peaks in the complete dispersion regime.
Institute of Scientific and Technical Information of China (English)
无
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 me...
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
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.
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.
Calculation of muscle forces during normal gait under consideration of femoral bending moments.
Lutz, Frederick; Mastel, Roland; Runge, Martin; Stief, Felix; Schmidt, André; Meurer, Andrea; Witte, Hartmut
2016-09-01
This paper introduces a new approach for computing lower extremity muscle forces by incorporating equations that consider "bone structure" and "prevention of bending by load reduction" into existing optimization algorithms. Lower extremity muscle and joint forces, during normal gait, were calculated and compared using two different optimization approaches. We added constraint equations that prevent femoral bending loads to an existing approach that considers "minimal total muscular force". Gait parameters such as kinematics, ground reaction forces, and surface electromyographic activation patterns were examined using standardized gait analysis. A subject-specific anatomic model of the lower extremities, obtained from magnetic resonance images of a healthy male, was used for the simulations. Finite element analysis was used to calculate femoral loads. The conventional method of calculating muscle forces leads to higher rates of femoral bending and structural stress than the new approach. Adding equations with structural subject-specific parameters in our new approach resulted in reduced femoral stress patterns. These findings show that our new approach improves the accuracy of femoral stress and strain simulations. Structural overloads caused by bending can be avoided during inverse calculation of muscle forces.
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.
DEFF Research Database (Denmark)
Andersen, Ingrid Marie Vincent; Jensen, Jørgen Juncher
2012-01-01
of 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 the 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...
Energy Technology Data Exchange (ETDEWEB)
Soerensen, B.F.; Joergensen, K.; Oestergaard, R.C. [Risoe National Lab., Materials Dept., Roskilde (Denmark); Jacobsen, T.K. [LM Glasfiber A/S, Lunderskov (Denmark)
2004-03-01
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 ratio between 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 be obtained by a J integral based approach. As a preliminary example, fracture of adhesive joints between two glass-fibre laminates was studied. The mixed mode fracture resistance increased with increasing crack length due to fibre cross over bridging, eventually reaching a steady-state level (R-curve behaviour). The steady-state fracture toughness level increased with increasing tangential crack opening displacement. Cohesive stresses were determined by a J integral approach. The deducted shear stress was found to be relative high ({approx} = 20 MPa) in comparison with the normal stress ({approx} = 1 MPa). (au)
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.
Liu, Yang; Shu, Dong-Wei
2014-08-01
Delaminations in structures may significantly reduce the stiffness and strength of the structures and may affect their vibration characteristics. As structural components, beams have been used for various purposes, in many of which beams are often subjected to axial loads and static end moments. In the present study, an analytical solution is developed to study the coupled bending-torsion vibration of a homogeneous beam with a single delamination subjected to axial loads and static end moments. Euler-Bernoulli beam theory and the "free mode" assumption in delamination vibration are adopted. This is the first study of the influences of static end moments upon the effects of delaminations on natural frequencies, critical buckling loads and critical moments for lateral instability. The results show that the effects of delamination on reducing natural frequencies, critical buckling load and critical moment for lateral instability are aggravated by the presence of static end moment. In turn, the effects of static end moments on vibration and instability characteristics are affected by the presence of delamination. The analytical results of this study can serve as a benchmark for finite element method and other numerical solutions.
舵机弯矩电动加载测试系统的设计%Design of Motor-Driven Bending Moment Loading Test System
Institute of Scientific and Technical Information of China (English)
周军; 刘光辉; 周凤岐; 张佼龙
2011-01-01
针对舵机测试需求,设计了一种弯矩电动加载测试系统.系统以直流电机为执行元件能够实现几百到几万牛力加载,介绍了系统的工作原理和机械结构,分析计算了弯矩加载对其他力矩加载的干扰和系统影响,从测试技术要求上论证了方案的可行性.最后进行了理论分析和研究,建立了加载系统的数学模型,基于PID控制算法,进行了计算机仿真.仿真结果表明,能够满足系统预定的性能指标要求.%To meet the requirements to current rudder motor test, the bending moment loading test system is designed. The system can achieve a few hundred to tens of thousands of N force output with DC motor driven. Based on an introduction to the structure and principle of electrical loading system, and the calculation of disturbance on torque from bending moment, the test system design is feasible to meet rudder motor test requirements. A mathematical model of the system is established to analyze and to computer simulate with PID control arithmetic. Simulation results indicated that the performance of the motor-driven bending moment loading test system is competent for rudder motor test.
DEFF Research Database (Denmark)
Jensen, Jørgen Juncher; Mansour, A. E.
2003-01-01
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...... 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...
Djoković, Jelena M.; Nikolić, Ružica R.; Bujňák, Ján
2015-12-01
In this paper it is analyzed the welded T-joint exposed to the axial tensile force and the bending moment, for determining the impact of the weld geometry on the fracture mechanics parameters. The stress intensity factor was calculated analytically, based on the concept of the linear elastic fracture mechanics (LEFM), by application of the Mathematica® programming routine. The presence of the weld was taken into account through the corresponding correction factors. The results show that increase of the size of the triangular welds leads to decrease of the stress intensity factor, while the SIF increases with increase of the welds' width. The ratio of the two welded plates' thicknesses shows that plate thicknesses do not exhibit significant influence on the stress intensity factor behavior.
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; 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.
Kopferman, H; Massey, H S W
1958-01-01
Nuclear Moments focuses on the processes, methodologies, reactions, and transformations of molecules and atoms, including magnetic resonance and nuclear moments. The book first offers information on nuclear moments in free atoms and molecules, including theoretical foundations of hyperfine structure, isotope shift, spectra of diatomic molecules, and vector model of molecules. The manuscript then takes a look at nuclear moments in liquids and crystals. Discussions focus on nuclear paramagnetic and magnetic resonance and nuclear quadrupole resonance. The text discusses nuclear moments and nucl
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.
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...
Institute of Scientific and Technical Information of China (English)
陈丽华; 李爱群; 娄宇; 李培彬
2009-01-01
Static load tests and bearing capacity analyses are cardeA out for two outer-plated steel-concrete continuous composite beams.The load-deflection curve and the loat-strain culve of specimens are obtained and analyzed.The test results indicate that effective cooperation can be achieved by the shear-resistant connection between the reinforcement in the negative moment area and the outer-plated steel beam,and the overall working performance of the composite beams is favorable.At the load-bearing limiting state,the plastic strain on the maximum negative and positive moment section becomes fully developed so as to form relatively ideal plastic hinges.With the increase in the reinforcement ratio,the moment-carrying capacity of the composite beams improves significantly,but the ductility of the beams and the rotation ability of the plastic hinges decrease.The formulae for calculating the limit bending capacity in the negative moment area of outer-plated steel-concrete composite beams are proposed based on the test data.The calculated results agree well with the test results.%对2根外包钢-混凝土连续梁试件进行了静力加载实验研究与承栽力分析.测量并分析了试件的荷栽-挠度及荷载-应变关系曲线.结果表明:外包钢-混凝土组合梁负弯矩区钢筋和外包钢梁通过抗剪连接措施能有效地共同工作,整体工作性能良好.在承栽能力极限状态,负弯矩和正弯矩最大截面的塑性应变均充分发展,并形成比较理想的塑性铰.随着配筋率的提高,组合梁受弯承栽力明显提高,而延性和转动能力相应降低.在试验数据基础上,给出了外包钢-混凝土组合梁在负弯矩区极限受弯承载力的计算公式,计算结果与实验结果吻合良好.
Chen, Samuel; Arsenault, Marc; Moglo, Kodjo
2012-11-01
The human neck is susceptible to traumatic injuries due to impacts as well as chronic injuries caused by loads such as those attributed to the wearing of heavy headgear. To facilitate the analysis of the loads that cause injuries to the cervical spine, it is possible to replicate the human neck's behaviour with mechanical devices. The goal of this work is to lay the foundation for the eventual development of a novel mechanism used to simulate the behaviour of the cervical spine during laboratory experiments. The research presented herein focuses on the design of a mechanism capable of reproducing the non-linear relationships between moments applied to the C3 vertebra and its corresponding rotations with respect to the C4 vertebra. The geometrical and mechanical properties of the mechanism are optimized based on the ability of the latter to replicate the load-deflection profile of the osteoligamentous structure of the C3-C4 vertebral pair in the flexion-extension and lateral bending directions. The results show that the proposed design concept is capable of faithfully replicating the non-linear behaviour of the motion segment within acceptable tolerances.
Institute of Scientific and Technical Information of China (English)
王玮波; R.; A.; SHENOI; 崔维成
2006-01-01
The snap buckling case in a curved composite beam under a closing bending moment is dealt with.A theoretical approach is developed for the non-linear problem of delamination buckling which is likely to occur in curved composite structures.The approach is based on large deflection characterisation of a curved beam,coupled with fracture mechanics concepts.The general solution is applied to analyse a special case in which delamination occurs very close to inner surface of the beam and snap buckling happens in this delaminated thin layer. The effect of the arc angle of delamination crack on the critical load is also studied.%研究了复合材料曲梁在受到合拢弯矩作用下发生的屈曲情况,并给出一种理论解析方法来分析这种很可能发生在复合材料弯曲结构中的脱层耦合屈曲问题.该方法是基于曲梁大变形理论及断裂力学而提出来的.文中并用该解析方法分析了一个特定的常见的情况,在该题例中脱层发生在非常靠近内表面处并且突变屈曲就发生在该薄脱层.在文中也对脱层裂纹的弧角对极限载荷的影响进行了研究.
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
Paul R. Reed; Carol J. Cumber
2000-01-01
In October, 1996 Private Moments, an adult novelty store, opened for business in Huntsville, Texas. Huntsville had no ordinances in place to prevent the opening of this type of business. In fact, the local Small Business Development Center provided guidance and assistance to Edward Delagarza, the founder and owner of Private Moments. Many of the Huntsville citizens, unhappy with the opening of Private Moments, approached the City Council requesting that it be closed immediately and asked for ...
Bending stresses in Facetted Glass Shells
DEFF Research Database (Denmark)
Bagger, Anne; Jönsson, Jeppe; Almegaard, Henrik
2008-01-01
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...
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.
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 secon......-torus symmetry in terms of tri-symplectic geometry of four-manifolds. (C) 2012 Elsevier Inc. All rights reserved....
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 c......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 cluster of knots. In a previous investigation test specimens, each containing one weak zone, have been tested in bending separately. Based on these tests a hierarchical model with two levels was formulated. The test results show that the bending strength of the long timber members on the average is 5...
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
2002-01-01
A Japanese team has found a way to bend and shape silicon substrates by growing a thin layer of diamond on top. The technique has been proposed as an alternative to mechanical bending, which is currently used to make reflective lenses for X-ray systems and particle physics systems (2 paragraphs).
Bending Capacity of Middle Joints of Upholstered Furniture Frames
Directory of Open Access Journals (Sweden)
Vasiliki Kamperidou, Vasileios Vasileiou
2012-12-01
Full Text Available This study evaluates the edgewise bending moment capacity of the four most frequently used middle joints in the upholstered furniture frames. The research included the following joints: Mortise and Tenon, double Dowel, Corner Blocks and double Gusset Plates, designed in the form of middle joints and made of beech and poplar solid wood. The test results indicated that regarding the edgewise bending force, the strongest middle joint was the double dowel joint made of beech wood (1896.9 N, while the respective joint made of poplar marked quite a low value of bending force (937.2 N. The strength of wooden corner blocks was proved to be quite powerful, made either of beech wood, poplar wood or the combination of the two wood species (beech: 1881.8 N, poplar: 1237.6 N, beech-poplar: 1783.6 N. The gusset plate joint made of beech resulted in weaker values (1378.2 N, compared to the dowel and corner block joints made of beech, whereas the same joint made of poplar demonstrated very satisfying values of edgewise bending force (1471.8 N. Finally, the mortise and tenon joint appeared to have the lowest strength, both in the case of beech (1306 N and poplar (634 N. The highest coeffi cient of elasticity (CE derived from double gusset plate joint, made of beech. All the joints showed good elasticity, except the mortise and tenon joint made of poplar, as well as, the dowel joint made of poplar, which recorded the lowest elasticity values of all. Generally, beech wood resulted in stronger and more elastic joints compared to poplar.
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.
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),…
Bending and stretching of plates
Mansfield, E H; Hemp, W S
1964-01-01
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
Bending strength of delaminated aerospace composites.
Kinawy, Moustafa; Butler, Richard; Hunt, Giles W
2012-04-28
Buckling-driven delamination is considered among the most critical failure modes in composite laminates. This paper examines the propagation of delaminations in a beam under pure bending. A pre-developed analytical model to predict the critical buckling moment of a thin sub-laminate is extended to account for propagation prediction, using mixed-mode fracture analysis. Fractography analysis is performed to distinguish between mode I and mode II contributions to the final failure of specimens. Comparison between experimental results and analysis shows agreement to within 5 per cent in static propagation moment for two different materials. It is concluded that static fracture is almost entirely driven by mode II effects. This result was unexpected because it arises from a buckling mode that opens the delamination. For this reason, and because of the excellent repeatability of the experiments, the method of testing may be a promising means of establishing the critical value of mode II fracture toughness, G(IIC), of the material. Fatigue testing on similar samples showed that buckled delamination resulted in a fatigue threshold that was over 80 per cent lower than the static propagation moment. Such an outcome highlights the significance of predicting snap-buckling moment and subsequent propagation for design purposes.
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)
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.
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...
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...
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.
Boundary effects in welded steel moment connections
Lee, Kyoung-Hyeog
Unprecedented widespread failure of welded moment connections in steel frames caused by the 1994 Northridge and the 1995 Kobe earthquakes have alarmed the engineering communities throughout the world. Welded moment connections in steel frames have been traditionally designed by using the classical beam theory which leads to assumptions that the flanges transfer moment while the web connection primarily resists the shear force. However, this study shows that the magnitude and direction of the principal stresses in the connection region are better approximated by using truss analogy rather than the classical beam theory. Accordingly, both the bending moment and the shear force are transferred across the connection near the beam flanges through diagonal strut action. Thus, the beam flange region of the traditionally designed connection is overloaded. This conclusion explains, to a large extent, the recently observed steel moment connection failures. In this study, detailed finite element analyses were carried out for a representative beam-to-column subassemblage with fully welded connection. The stress distribution in the beam web and flanges in the vicinity of the connection were closely studied. The factors responsible for stress redistribution and concentration were identified by using fundamental principles of mechanics. It was concluded that peak resultant stresses can exceed the values used in simple design calculations by large margins. Using the finite element analysis results and the truss analogy to establish a realistic load path in the connection, a practical and more rational analysis and design procedure was developed. The proposed design procedure and the new connection details were successfully validated through cyclic load testing of a nearly full size specimen. The truss model represented the force transmission around the beam-to-column moment connection region very well. Results of the finite element analyses and the laboratory testing showed
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.
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...
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
Luo, Yajun; Xu, Minglong; Yan, Bo; Zhang, Xinong
2015-03-01
With increasing of the geometry of various space structures, they easily bring low-frequency, longtime and more bending modal responses. Therefore, it is necessary to suppress effectually the vibration responses above. Adaptive structure design is a common method using the piezoelectric material. However, the conventional piezoelectric actuators hardly control effectually these responses owing to the inadequate actuated performance. This paper first introduces the design of a new dual-stack piezoelectric actuator, which has the bidirectional (can act in both push and pull directions) actuated advantage, using a pair of matching piezoelectric stacks within the actuator house. Two stacks are integrated in a mechanically opposing configuration and are electrically operated out of phase. Further, we design the piezoelectric bending actuator using two dual-stack piezoelectric actuators and a fixed device, and then a five-meter hoop truss can use it to perform the active vibration control. Here the truss is mainly applied to simulate a large hoop mesh antenna. Then, we set up the active control system based on the PD algorithm and build the simulation model by the Matlab/Simulink platform. The simulation results point out the PBA can produce enough actuated moment to suppress effectually the first-order modal response of the hoop truss. Finally, we perform three experiments including one uncontrolled case and two PD controlled cases. The two control cases mainly consider whether the driving voltages are offset or not. The experimental results of both control cases are in accordance with the better simulated analysis. The control ratios of the decay time of the first-order modal response are up to more than 30 percent in the simulations and experiments. That is, this bending actuator has good application foreground in controlling the bending modes of the spacecrafts with a larger size.
Moment inference from tomograms
Day-Lewis, F. D.; Chen, Y.; Singha, K.
2007-01-01
Time-lapse geophysical tomography can provide valuable qualitative insights into hydrologic transport phenomena associated with aquifer dynamics, tracer experiments, and engineered remediation. Increasingly, tomograms are used to infer the spatial and/or temporal moments of solute plumes; these moments provide quantitative information about transport processes (e.g., advection, dispersion, and rate-limited mass transfer) and controlling parameters (e.g., permeability, dispersivity, and rate coefficients). The reliability of moments calculated from tomograms is, however, poorly understood because classic approaches to image appraisal (e.g., the model resolution matrix) are not directly applicable to moment inference. Here, we present a semi-analytical approach to construct a moment resolution matrix based on (1) the classic model resolution matrix and (2) image reconstruction from orthogonal moments. Numerical results for radar and electrical-resistivity imaging of solute plumes demonstrate that moment values calculated from tomograms depend strongly on plume location within the tomogram, survey geometry, regularization criteria, and measurement error. Copyright 2007 by the American Geophysical Union.
Sheet Bending using Soft Tools
Sinke, J.
2011-05-01
Sheet bending is usually performed by air bending and V-die bending processes. Both processes apply rigid tools. These solid tools facilitate the generation of software for the numerical control of those processes. When the lower rigid die is replaced with a soft or rubber tool, the numerical control becomes much more difficult, since the soft tool deforms too. Compared to other bending processes the rubber backed bending process has some distinct advantages, like large radius-to-thickness ratios, applicability to materials with topcoats, well defined radii, and the feasibility of forming details (ridges, beads). These advantages may give the process exclusive benefits over conventional bending processes, not only for industries related to mechanical engineering and sheet metal forming, but also for other disciplines like Architecture and Industrial Design The largest disadvantage is that also the soft (rubber) tool deforms. Although the tool deformation is elastic and recovers after each process cycle, the applied force during bending is related to the deformation of the metal sheet and the deformation of the rubber. The deformation of the rubber interacts with the process but also with sheet parameters. This makes the numerical control of the process much more complicated. This paper presents a model for the bending of sheet materials using a rubber lower die. This model can be implemented in software in order to control the bending process numerically. The model itself is based on numerical and experimental research. In this research a number of variables related to the tooling and the material have been evaluated. The numerical part of the research was used to investigate the influence of the features of the soft lower tool, like the hardness and dimensions, and the influence of the sheet thickness, which also interacts with the soft tool deformation. The experimental research was focused on the relation between the machine control parameters and the most
Oide Effect and Radiation in Bending Magnets
Blanco, Oscar; Bambade, Philip
2014-01-01
Including radiation effects during lattice design optimization is crucial in high energy accelerators. Oide effect and radiation in bending magnets are reviewed aiming to include them in the optical design process to minimize the IP beam size. The Oide double integral is expressed in simpler terms in order to speed up calculations, concluding in how longer quadrupoles with lower gradients may help reducing the Oide effect. Radiation in bending magnets is reviewed for linear lattices, generalizing to the case when the final dispersion is different from zero and making comparisons with theoretical results and particle tracking. An agreement between the theory, the implemented approximation included in MAPCLASS2 and the six-dimensional tracking in PLACET has been found.
Bending behavior of double-row stabilizing piles with constructional time delay
Institute of Scientific and Technical Information of China (English)
Yang YU; Yue-quan SHANG; Hong-yue SUN
2012-01-01
The bending behavior of double-row stabilizing plies is associated with the constructional time delay (CTD),which can be defined as the time interval between the installations of the front stabilizing pile and the rear stabilizing pile.This paper investigates the effect of CTD on the bending moments of double-row stabilizing piles and a method for determining the optimal CTD is proposed.The stabilizing pile is modeled as a cantilever pile embedded in the Winkler elastic foundation.A triangular distributed earth pressure is assumed on the pile segment in the sliding layer.The front stabilizing pile and the rear stabilizing pile are connected by a beam with pinned joints.The analytical solutions of bending moments on the front and the rear stabilizing piles are derived and the accuracy of bending moment solutions is validated by comparing the tensile strain measured from the Hongyan landslide project,Taizhou,Zhejiang,China.It is concluded that CTD has a significant influence on the bending moments of double-row stabilizing piles.An optimal CTD can be obtained when the maximum tensile stress in the front stabilizing pile is equal to that in the rear stabilizing pile,which is 1.4 months for the Hongyan landslide project.
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.
Requirements for Bend Insensitive Fiber in Millimeter-Wave Fronthaul Systems
DEFF Research Database (Denmark)
Rommel, Simon; Cavalcante, Lucas Costa Pereira; Vegas Olmos, Juan José;
2015-01-01
The impact of fiber bending on mm-wave radioover-fiber transmission is investigated and the need for bend insensitive fiber for front-haul installation confirmed. A 70m Wband hybrid photonic-wireless link including bend insensitive fiber is demonstrated with BER
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
Irradiated Effect on Shear-Moment Interaction of Reinforced Concrete Slab
Energy Technology Data Exchange (ETDEWEB)
Kwon, Tae-Hyun; Kim, Jun Yeon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, HyungTae; Park, Kyoungsoo [Yonsei University, Seoul (Korea, Republic of); Kim, Sang-Ho [Hyundai Engineering, Seoul (Korea, Republic of)
2015-10-15
Several deleterious mechanisms include chronic high-temperature exposure, freeze-thaw, and chemical attack and have been reviewed extensively in the literature. On the other hand, the effect of irradiation on RC needs further investigations for the long-term operation of existing NPPs. In this regard, the RC biological shield structure is located in closest proximity to a reactor core and expected to see the highest levels of irradiation over the lifetime. The biological shield structure may undergo a large lateral load from earthquake and become thicker for a suitable shielding. Although the bending strength is easily predictable with the altering steel properties, the more complete behaviors should be studied to see if the promised performance is achievable. Given this, in this study, the shear-moment (VM) interaction of a typical one-way slab representing the biological shield structure is investigated with incremental neutron irradiation. The effect of radiation on the behavior of one-way slab is presented by the shear and moment capacity interaction diagram. The results suggest that the yield strength increase of the longitudinal reinforcement barely affects the shear strength but it increases the bending strength significantly. This may be misleading, however, as the structural capacity to observe the energy from environmental loadings such as earthquake would be actually reducing.
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.
Directory of Open Access Journals (Sweden)
José Christian Chanchí Golondrino
2008-01-01
Full Text Available El presente artículo esboza dos aproximaciones sobre la ecuación de diseño a momento flexionante de secciones T en concreto reforzado que se comportan como secciones rectangulares y que trabajan como viguetería de losas aligeradas. La primera aproximación discute la viabilidad de usar el ancho del nervio de la vigueta en lugar de usar el ancho efectivo de la aleta, dentro del proceso de la obtención del acero, requerida para asumir un momento flexionante; la segunda aproximación discute la viabilidad de aproximar la ecuación cuadrática que rige la obtención del área del acero requerida para obtener un momento flexionante en una ecuación lineal, cuyas únicas variables son el área del acero y la altura efectiva de la sección T. Se ha dimensionado geométricamente un conjunto de secciones de losas aligeradas siguiendo los requisitos del título C13 de la norma sismo resistente colombiana NSR98, los cuales se obtuvieron para un modelo simplemente apoyado, cuya luz varía entre [2 - 7] m y el ancho del casetón ente [0.30 - 1] m. El dimensionamiento antes mencionado fue utilizado para sensibilizar la efectividad de cada una de las aproximaciones propuestas respecto a la solución general para la obtención del área del acero de la sección T que se comporta como rectangular.This article presents two approaches on the moment design equation of T shaped beams. Particularly the beam's T cross section analyzed behaves like a rectangular cross section when the beam works like a component of a slab system built from a set of T shaped beams. The first approach discusses the feasibility to use the web width instead of effective flange width to obtain the steel area associated to the moment solicitation of T shaped beam. The second approach discusses the feasibility to approach the quadratic equation used to obtain the steel required to take the bending moment into linear equation related to variables such as steel area and the effective depth
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)
Bends in nanotubes allow electric spin control and coupling
DEFF Research Database (Denmark)
Flensberg, Karsten; Marcus, Charles Masamed
2010-01-01
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...... 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....
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.
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
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
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.
Doraiswamy, Srikrishna; Rao, Ashwin; Srinivasa, A. R.
2013-04-01
Modeling superelastic behavior of shape memory alloys (SMA) has received considerable attention due to SMAs ability to recover large strains with associated loading{unloading hysteresis enabling them to find many applications. In this work, a simple mechanics of materials modeling approach for simulating superelastic responses of SMA components under tension and bending loading conditions is developed. Following Doraiswamy, Rao and Srinivasa's1 approach, the key idea here would be in separating the thermoelastic and the dissipative part of the hysteretic response with a Gibbs potential based formulation which includes both thermal and mechanical loading in the same framework. The dissipative part is then handled by a discrete Preisach model. The model is formulated directly using tensile stress{strain or bending moment{curvature rather than solving for non-homogeneous stress and strains across the specimen cross-sections and then integrating the same especially for bending loading conditions. The model is capable of simulating complex superelastic responses with multiple internal loops and provides an improved treatment for temperature dependence associated with superelastic responses. The model results are verified with experimental results on SMA components like wires and beams at different temperatures.
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.
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
Pieters, Jurgen
2001-01-01
'Moments of Negotiation' offers the first book-length and indepth analysis of the New Historicist reading method, which the American Shakespeare-scolar Stephen Greenblatt introduced at the beginning of the 1980s. Ever since, Greenblatt has been hailed as the prime representative of this movement, wh
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
Bending behavior of lapped plastic ehv cables
Energy Technology Data Exchange (ETDEWEB)
Morgan, G H; Muller, A C
1980-01-01
One of the factors delaying the development of lapped polymeric cables has been their reputed poor bending characteristics. Complementary programs were begun at BNL several years ago to mathematically model the bending of synthetic tape cables and to develop novel plastic tapes designed to have moduli more favorable to bending. A series of bend tests was recently completed to evaluate the bending performance of several tapes developed for use in experimental superconducting cables. The program is discussed and the results of the bend tests are summarized.
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
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.
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).
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.
Higher Moments of Weighted Integrals of Non-Gaussian Fields
DEFF Research Database (Denmark)
Mohr, Gunnar
1996-01-01
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...... with 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)....
Distributions on unbounded moment spaces and random moment sequences
Nagel, Jan
2010-01-01
In this paper we define distributions on moment spaces corresponding to measures on the real line with an unbounded support. We identify these distributions as limiting distributions of random moment vectors defined on compact moment spaces and as distributions corresponding to random spectral measures associated with the Jacobi, Laguerre and Hermite ensemble from random matrix theory. For random vectors on the unbounded moment spaces we prove a central limit theorem where the centering vectors correspond to the moments of the Marchenko-Pastur distribution and Wigner's semi-circle law.
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...
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
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.
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%.
How two-dimensional bending can extraordinarily stiffen thin sheets
Pini, V.; Ruz, J. J.; Kosaka, P. M.; Malvar, O.; Calleja, M.; Tamayo, J.
2016-07-01
Curved thin sheets are ubiquitously found in nature and manmade structures from macro- to nanoscale. Within the framework of classical thin plate theory, the stiffness of thin sheets is independent of its bending state for small deflections. This assumption, however, goes against intuition. Simple experiments with a cantilever sheet made of paper show that the cantilever stiffness largely increases with small amounts of transversal curvature. We here demonstrate by using simple geometric arguments that thin sheets subject to two-dimensional bending necessarily develop internal stresses. The coupling between the internal stresses and the bending moments can increase the stiffness of the plate by several times. We develop a theory that describes the stiffness of curved thin sheets with simple equations in terms of the longitudinal and transversal curvatures. The theory predicts experimental results with a macroscopic cantilever sheet as well as numerical simulations by the finite element method. The results shed new light on plant and insect wing biomechanics and provide an easy route to engineer micro- and nanomechanical structures based on thin materials with extraordinary stiffness tunability.
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.
A Novel Low-Cost, Large Curvature Bend Sensor Based on a Bowden-Cable.
Jeong, Useok; Cho, Kyu-Jin
2016-06-24
Bend sensors have been developed based on conductive ink, optical fiber, and electronic textiles. Each type has advantages and disadvantages in terms of performance, ease of use, and cost. This study proposes a new and low-cost bend sensor that can measure a wide range of accumulated bend angles with large curvatures. This bend sensor utilizes a Bowden-cable, which consists of a coil sheath and an inner wire. Displacement changes of the Bowden-cable's inner wire, when the shape of the sheath changes, have been considered to be a position error in previous studies. However, this study takes advantage of this position error to detect the bend angle of the sheath. The bend angle of the sensor can be calculated from the displacement measurement of the sensing wire using a Hall-effect sensor or a potentiometer. Simulations and experiments have shown that the accumulated bend angle of the sensor is linearly related to the sensor signal, with an R-square value up to 0.9969 and a root mean square error of 2% of the full sensing range. The proposed sensor is not affected by a bend curvature of up to 80.0 m(-1), unlike previous bend sensors. The proposed sensor is expected to be useful for various applications, including motion capture devices, wearable robots, surgical devices, or generally any device that requires an affordable and low-cost bend sensor.
The quantitative check-measure of the bend strain parameters of the rotating components
Institute of Scientific and Technical Information of China (English)
李文华; 乔中涛
2002-01-01
Based on the principle of the electric-magnetic check-measure, this paper puts forward a new technology and method that use the magnetic marks to check and measure the dynamic physical parameters such as angle speed, bending strain,stress and bending moment. The principles of the check-measure and the dealing and exchanging technology about signals have been demonstrated and the rotating components have been made up. The timely and quantitative check-measure of the dynamic physical parameters during the component in working has been realized by using computer control.
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,
Moment Distributions of Phase Type
DEFF Research Database (Denmark)
Bladt, Mogens; Nielsen, Bo Friis
-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...... alternative representation in terms of sub{intensity matrices. Finally we are able to nd explicit expressions for both the Lorenz curve and the Gini index....
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.)
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.)
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 ...
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
Theory of the Muon Anomalous Magnetic Moment
Melnikov, Kirill
2006-01-01
The theory of the muon anomalous magnetic moment is "particle physics in a nutshell" and as such is interesting, exciting and difficult. The current precision of the experimental value for this quantity, improved significantly in the past several years due to experiment E821 at Brookhaven National Laboratory, is so high that a large number of subtle effects not relevant previously, become important for the interpretation of the experimental result. The theory of the muon anomalous magnetic moment is at the cutting edge of current research in particle physics and includes multiloop calculations in both QED and electroweak theory, precision low-energy hadron physics, isospin violations and scattering of light by light. Any deviation between the theoretical prediction and the experimental value might be interpreted as a signal of an as-yet-unknown new physics. This book provides a comprehensive review of the theory of the muon anomalous magnetic moment.
FACTORS INFLUENCING BENDING RIGIDITY OF SUBMERGED VEGETATION
Institute of Scientific and Technical Information of China (English)
WU Long-hua; YANG Xiao-li
2011-01-01
The bending rigidity of submerged vegetation is closely related with vegetative drag force.This work aims at determining the effects of flow conditions and characteristics of vegetation on the bending rigidity of submerged vegetation.Based on the dimensional analysis method,the factors influencing the bending rigidity of individual submerged vegetation were analyzed.The relationship between the relative bending rigidity and its influencing factors was investigated by experimental observation,and a relative bending rigidity expression for submerged vegetation was obtained by means of multiple linear regression method.The results show that the submerged vegetation has three states under different inflow conditions,and the each critical relative bending rigidity of individual submerged vegetation was determined for the different states of submerged vegetation.
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.
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
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%
Investigation on the Free Micro-bending Device and Size Effect for H62 Brass%H62黄铜自由微弯曲装置及其尺度效应
Institute of Scientific and Technical Information of China (English)
许桢英; 王匀; 吴俊峰; 朱永书
2012-01-01
Since the micro-bending know-how is different from traditional bending, the device for micro-bending is designed according to the characteristics of micro-bending, and the device mainly includes transmission mechanism, die, data acquisition system and positioning system. Using this device, an experiment of free micro-bending was implemented for the ultra-thin sheet of H62 brass with different thicknesses :0. 1 mm 0. 2mm and 0. 4mm, and the velocity of the die is 0. 077mm/s. According to the curve of bending moment-defeleetion which is fitted by the collected dala, the results show that bending moment decreases with the increasing of average grain size owing to the size effect influence. This can be explained by the Hall-Petch theory and surface layer modeling.%微型化和尺度效应使得微弯曲在成形工艺、方法和装置上和传统弯曲有很大差异.本文针对微弯曲成形的特点研制出微弯曲成形装置,主要包括传动机构、模具、数据采集模块和定位系统.利用该装置,在0.077 mm/s的成形速度下,分别对0.1 mm、0.2 mm和0.4 mm厚的H62黄铜超薄板进行自由弯曲实验,根据采集数据得到弯矩-挠度拟合曲线,分析了微弯曲过程中的尺寸效应:即试样尺寸与晶粒尺寸对弯矩的影响规律,结果表明弯矩随着晶粒尺寸的增大而减小,并用表面层模型和细晶强化理论来进行解释.
All joint moments significantly contribute to trunk angular acceleration.
Nott, Cameron R; Zajac, Felix E; Neptune, Richard R; Kautz, Steven A
2010-09-17
Computationally advanced biomechanical analyses of gait demonstrate the often counter-intuitive roles of joint moments on various aspects of gait such as propulsion, swing initiation, and balance. Each joint moment can produce linear and angular acceleration of all body segments (including those on which the moment does not directly act) due to the dynamic coupling inherent in the interconnected musculoskeletal system. This study presents quantitative relationships between individual joint moments and trunk control with respect to balance during gait to show that the ankle, knee, and hip joint moments all affect the angular acceleration of the trunk. We show that trunk angular acceleration is affected by all joints in the leg with varying degrees of dependence during the gait cycle. Furthermore, it is shown that inter-planar coupling exists and a two-dimensional analysis of trunk balance neglects important out-of-plane joint moments that affect trunk angular acceleration.
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.
Multilevel light bending in nanoplasmonics
El Sherif, Mohamed H.; Ahmed, Osman S.; Bakr, Mohamed H.; Swillam, Mohamed A.
2014-03-01
Nanoplasmonic optical interconnects is proposed to mitigate challenges facing electronics integration. It provides fast and miniaturized data channel that overcome the diffraction limit. We present a three dimensional plasmonic coupler that vertically bends the light to multilevel circuit configurations. It exploits light guiding in nanoscale plasmonic slot waveguides (PSWs). A triangularly-shaped plasmonic slot waveguide rotator is introduced to attain such coupling with good efficiency over a wide bandwidth. Using this approach, light propagating in a horizontal direction is easily converted and coupled to propagate in the vertical direction and vice versa. The proposed configuration is further extended to the design of a multilayer power divider/combiner with ultra-compact footprint that guides the light to multiple channels. A detailed study of the triangular rotator is demonstrated with the analysis of multiple configurations. This structure is suitable for efficient coupling and splitting in multilevel nano circuit environment.
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.
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.
Proteomic Analysis of Fruit Bending in Cucumber (Cucumis sativus L.)
Institute of Scientific and Technical Information of China (English)
WANG Li-li; ZHANG Peng; QIN Zhi-wei; ZHOU Xiu-yan
2014-01-01
In cucumber, fruit shape is an important quality criterion, and fruit bending is known to limit growth, yield, and taste. To investigate the post-transcriptional changes that regulate fruit bending and to better understand the underlying molecular mechanisms, we generated a proteomic proifle of the abdomen and back of cucumber bending fruit. Two-dimensional gel electrophoresis (2-DE) allowed the detection of approximately 900 distinct protein spots in each gel, 32 of which were differentially expressed in the abdomen and back of bending cucumber fruit. Ten of the differentially expressed proteins were analyzed using matrix-assisted laser ionization time of lfight mass spectrometry (MALDI-TOF/MS). A search of primary databases showed that the identiifed proteins are involved in various metabolic processes and cellular responses, including photosynthesis metabolism, energy metabolism, defense and stress response, and regulation. The identiifed proteins included large subunits of ribulose-1,5-bisphosphate carboxylase/oxygenase, which are involved in photosynthesis and photorespiratory metabolism, and isocitrate dehydrogenase, which is involved in the tricarboxylic acid cycle. It is possible that imbalances in catabolic and anabolic processes directly affect the bending of cucumber fruit. The predicted function of the cobalamin-independent methionine synthase isozyme is closely related to ethylene biosynthesis; fruit bending may be regulated by ethylene, or by ethylene signaling crosstalk during fruit development. The 14-3-3 protein is usually considered to be a regulation-related protein, which plays a role in regulating cell hyperplasia, cell differentiation during growth, and apoptosis during senescence. Involvement of guanosine triphosphate (GTP)-binding proteins in signal transmission is known to regulate the development of cells in cucumber fruits and to play a role in fruit shape variation. Patterns of protein expression showed high repeatability. We hypothesize
End effects on elbows subjected to moment loadings. [PWR; BWR
Energy Technology Data Exchange (ETDEWEB)
Rodabaugh, E.C.; Moore, S.E.
1982-01-01
So-called end effects for moment loadings on short-radius and long-radius butt welding elbows of various arc lengths are investigated with a view toward providing more accurate design formulas for critical piping systems. Data developed in this study, along with published information, were used to develop relatively simple design equations for elbows attached at both ends to long sections of straight pipe. These formulas are the basis for an alternate ASME Code procedure for evaluating the bending moment stresses in Class 1 nuclear piping (ASME Code Case N-319). The more complicated problems of elbows with other end conditions, e.g., flanges at one or both ends, are also considered. Comparisons of recently published experimental and theoretical studies with current industrial code design rules for these situations indicate that these rules also need to be improved.
Struppe, J.; Noack, F.; Klose, G.
1997-10-01
The frequency dependence of the longitudinal proton spin relaxation time T1 was measured by field-cycling and standard NMR techniques at different temperatures in the liquid crystalline lamellar phases of bilayer systems, composed of lipids, nonionic surfactants, and lipid-surfactant mixtures. We show by our data analysis, comparing various motional models such as layer undulations (LUs) and relaxation by translational diffusion mediated reorientations (TR), that collective layer undulations with their typical T1~ν behaviour determine the low frequency T1 dispersion in both unoriented and glass plate-oriented bilayer systems. The angular dependence of the T1 dispersion for the oriented bilayer system supports these findings and provides a more critical analysis of the two dimensional self-diffusion than in unoriented samples. The evaluated fitting parameters of the LU model allows, together with the measured second moment of the proton NMR signal for the lipid, calculation of the bending rigidity ϰc for these bilayers at different levels of hydration. The obtained values of ϰc turn out to be too large compared with the literature. However, using recent LU models (B. Halle) which include the obvious couplings between neighbouring bilayers at low Larmor frequencies, the corrected ϰc of the fully hydrated membrane systems are comparable to those obtained from the standard videooptical experiments. Therefore proton spin relaxation measure-ments at low Larmor frequencies with the field-cycling technique are a suitable means to determine the bending rigidity ϰc of model membrane systems at low hydrations and of systems containing surfactants.
Bending of the looping heart: differential growth revisited.
Shi, Yunfei; Yao, Jiang; Xu, Gang; Taber, Larry A
2014-08-01
In the early embryo, the primitive heart tube (HT) undergoes the morphogenetic process of c-looping as it bends and twists into a c-shaped tube. Despite intensive study for nearly a century, the physical forces that drive looping remain poorly understood. This is especially true for the bending component, which is the focus of this paper. For decades, experimental measurements of mitotic rates had seemingly eliminated differential growth as the cause of HT bending, as it has commonly been thought that the heart grows almost exclusively via hyperplasia before birth and hypertrophy after birth. Recently published data, however, suggests that hypertrophic growth may play a role in looping. To test this idea, we developed finite-element models that include regionally measured changes in myocardial volume over the HT. First, models based on idealized cylindrical geometry were used to simulate the bending process in isolated hearts, which bend without the complicating effects of external loads. With the number of free parameters in the model reduced to the extent possible, stress and strain distributions were compared to those measured in embryonic chick hearts that were isolated and cultured for 24 h. The results show that differential growth alone yields results that agree reasonably well with the trends in our data, but adding active changes in myocardial cell shape provides closer quantitative agreement with stress measurements. Next, the estimated parameters were extrapolated to a model based on realistic 3D geometry reconstructed from images of an actual chick heart. This model yields similar results and captures quite well the basic morphology of the looped heart. Overall, our study suggests that differential hypertrophic growth in the myocardium (MY) is the primary cause of the bending component of c-looping, with other mechanisms possibly playing lesser roles.
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...
Discontinious Galerkin formulations for thin bending problems
Nguyen, T.D.
2008-01-01
A structural thin bending problem is essentially associated with a fourth-order partial differential equation. Within the finite element framework, the numerical solution of thin bending problems demands the use of C^1 continuous shape functions. Elements using these functions are challenging and di
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...
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...
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.
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
2015-01-01
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...... in the present paper is based on time series of full scale measurements from three large container ships of 8600, 9400 and 14000 TEU. When carrying out the extreme value estimation the peak-over-threshold (POT) method combined with an appropriate extreme value distribution is applied. The choice of a proper...
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...
Photoacoustic elastic bending in thin film—Substrate system
Energy Technology Data Exchange (ETDEWEB)
Todorović, D. M., E-mail: dmtodor@imsi.bg.ac.rs [Institute for Multidisciplinary Research, University of Belgrade, P.O. Box 33, 11030 Belgrade (Serbia); Rabasović, M. D.; Markushev, D. D. [Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade-Zemun (Serbia)
2013-12-07
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.
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.
Wire and Cable Cold Bending Test
Colozza, Anthony
2010-01-01
One of the factors in assessing the applicability of wire or cable on the lunar surface is its flexibility under extreme cold conditions. Existing wire specifications did not address their mechanical behavior under cold, cryogenic temperature conditions. Therefore tests were performed to provide this information. To assess this characteristic 35 different insulated wire and cable pieces were cold soaked in liquid nitrogen. The segments were then subjected to bending and the force was recorded. Any failure of the insulation or jacketing was also documented for each sample tested. The bending force tests were performed at room temperature to provide a comparison to the change in force needed to bend the samples due to the low temperature conditions. The results from the bending tests were plotted and showed how various types of insulated wire and cable responded to bending under cold conditions. These results were then used to estimate the torque needed to unroll the wire under these low temperature conditions.
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)...
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...
Directory of Open Access Journals (Sweden)
Ricardo Faustino Teles
2010-03-01
Full Text Available This work aims to assess the bending properties of glued laminated timber beams (glulam manufactured with species red louro (Sextonia rubra. Laminations were nondestructively tested using the transverse vibration method (EMlam. Then 10 glulam beams were manufactured and tested in static bending according to ASTM D 198 standard, having modulus of elasticity (EM, modulus of rupture (fM, and bending moment (M determined. The finished beams were also tested by the transverse vibration method (EMvt. It was noted that the EMvt value was only 2% lower than the EM value. Using laminations with a high modulus of elasticity did allow effective gain in stiffness. Therefore, results indicate that the transverse vibration method is a valid, reliable technique both for testing glulam laminations and for assessing stiffness in finished beams. Bending properties in glulam beams were influenced by the stiffness of constituent laminations.
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...
Bend Properties of Sapphire Fibers at Elevated Temperatures. 1; Bend Survivability
Morscher, Gregory N.; Sayir, Haluk
1995-01-01
The effect of temperature on the bend radius that a c-axis-oriented sapphire fiber can withstand was determined for fibers of various diameter. Bend stress rupture tests were performed for times of 1-100 h and temperatures of 300-1700 C. Fibers would survive the bend test undeformed, would fracture or would deform. The bend survival radius was determined to be the radius above which no fibers fractured or deformed for a given time-temperature treatment. It was found that the ability of fibers to withstand curvature decreases substantially with time and increasing temperature and that fibers of smaller diameter (46-83 micron) withstood smaller bend radii than would be expected from just a difference in fiber diameter when compared with the bend results of the fibers of large diameter (144 micron). This was probably due to different flaw populations, causing high temperature bend failure for the tested sapphire fibers of different diameters.
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 methods in extremal geometry
De Laat, D.
2016-01-01
In this thesis we develop techniques for solving problems in extremal geometry. We give an infinite dimensional generalization of moment techniques from polynomial optimization. We use this to construct semidefinite programming hierarchies for approximating optimal packing densities and ground state
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.
Maximizing your teaching moment
... include feelings such as anger, denial, anxiety, or depression; beliefs and attitudes that are not aligned with learning; pain; acute illness; language or cultural differences; physical limitations; and learning differences.
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.
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.
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.
Low Loss S-Bend Structure With Tapered Curved Waveguides
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
A novel S-bend with tapered curved waveguides is proposed. The normalized transmitted power is greater than the conventional bend with weakly guided waveguides. Small size and low loss can be reached by the proposed S-bend.
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
Inquiry-Based Science: Turning Teachable Moments into Learnable Moments
Haug, Berit S.
2014-02-01
This study examines how an inquiry-based approach to teaching and learning creates teachable moments that can foster conceptual understanding in students, and how teachers capitalize upon these moments. Six elementary school teachers were videotaped as they implemented an integrated inquiry-based science and literacy curriculum in their classrooms. In this curriculum, science inquiry implies that students search for evidence in order to make and revise explanations based on the evidence found and through critical and logical thinking. Furthermore, the curriculum material is designed to address science key concepts multiple times through multiple modalities (do it, say it, read it, write it). Two types of teachable moments were identified: planned and spontaneous. Results suggest that the consolidation phases of inquiry, when students reinforce new knowledge and connect their empirical findings to theory, can be considered as planned teachable moments. These are phases of inquiry during which the teacher should expect, and be prepared for, student utterances that create opportunities to further student learning. Spontaneous teachable moments are instances when the teacher must choose to either follow the pace of the curriculum or adapt to the students' need. One implication of the study is that more teacher support is required in terms of how to plan for and effectively utilize the consolidation phases of inquiry.
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
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
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.
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.
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.
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.
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.
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.
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
Van Erps, Jürgen; Debaes, Christof; Nasilowski, Tomasz; Watté, Jan; Wojcik, Jan; Thienpont, Hugo
2008-03-31
We present the design of a low bending loss hole-assisted fiber for a 180?-bend fiber socket application, including a tolerance analysis for manufacturability. To this aim, we make use of statistical design methodology, combined with a fully vectorial mode solver. Two resulting designs are presented and their performance in terms of bending loss, coupling loss to Corning SMF-28 standard telecom fiber, and cut-off wavelength is calculated.
Matrix elements from moments of correlation functions
Bouchard, Chris; Orginos, Kostas; Richards, David
2016-01-01
Momentum-space derivatives of matrix elements can be related to their coordinate-space moments through the Fourier transform. We derive these expressions as a function of momentum transfer $Q^2$ for asymptotic in/out states consisting of a single hadron. We calculate corrections to the finite volume moments by studying the spatial dependence of the lattice correlation functions. This method permits the computation of not only the values of matrix elements at momenta accessible on the lattice, but also the momentum-space derivatives, providing {\\it a priori} information about the $Q^2$ dependence of form factors. As a specific application we use the method, at a single lattice spacing and with unphysically heavy quarks, to directly obtain the slope of the isovector form factor at various $Q^2$, whence the isovector charge radius. The method has potential application in the calculation of any hadronic matrix element with momentum transfer, including those relevant to hadronic weak decays.
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.
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.
Monte Carlo Volcano Seismic Moment Tensors
Waite, G. P.; Brill, K. A.; Lanza, F.
2015-12-01
Inverse modeling of volcano seismic sources can provide insight into the geometry and dynamics of volcanic conduits. But given the logistical challenges of working on an active volcano, seismic networks are typically deficient in spatial and temporal coverage; this potentially leads to large errors in source models. In addition, uncertainties in the centroid location and moment-tensor components, including volumetric components, are difficult to constrain from the linear inversion results, which leads to a poor understanding of the model space. In this study, we employ a nonlinear inversion using a Monte Carlo scheme with the objective of defining robustly resolved elements of model space. The model space is randomized by centroid location and moment tensor eigenvectors. Point sources densely sample the summit area and moment tensors are constrained to a randomly chosen geometry within the inversion; Green's functions for the random moment tensors are all calculated from modeled single forces, making the nonlinear inversion computationally reasonable. We apply this method to very-long-period (VLP) seismic events that accompany minor eruptions at Fuego volcano, Guatemala. The library of single force Green's functions is computed with a 3D finite-difference modeling algorithm through a homogeneous velocity-density model that includes topography, for a 3D grid of nodes, spaced 40 m apart, within the summit region. The homogenous velocity and density model is justified by long wavelength of VLP data. The nonlinear inversion reveals well resolved model features and informs the interpretation through a better understanding of the possible models. This approach can also be used to evaluate possible station geometries in order to optimize networks prior to deployment.
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
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...
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.
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...
Analysis of supersonic stall bending flutter in axial-flow compressor by actuator disk theory
Adamczyk, J. J.
1978-01-01
An analytical model was developed for predicting the onset of supersonic stall bending flutter in axial-flow compressors. The analysis is based on two-dimensional, compressible, unsteady actuator disk theory. It is applied to a rotor blade row by considering a cascade of airfoils. The effects of shock waves and flow separation are included in the model. Calculations show that the model predicts the onset, in an unshrouded rotor, of a bending flutter mode that exhibits many of the characteristics of supersonic stall bending flutter. The validity of the analysis for predicting this flutter mode is demonstrated.
Immediate effect of valgus bracing on knee joint moments in meniscectomised patients
DEFF Research Database (Denmark)
Thorning, Maria; Thorlund, Jonas Bloch; Roos, Ewa M;
2016-01-01
-dimensional analysis of gait, forward lunge and one-leg rise during two conditions: with and without a valgus unloader knee brace. Outcome measures included the peak and impulse of the knee adduction moment and the peak knee flexion moment. RESULTS: The peak knee flexion moment increased during brace condition...
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.
Updating neutrino magnetic moment constraints
Canas, B C; Parada, A; Tortola, M; Valle, J W F
2015-01-01
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 Lambda_i as well as 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 x 10^-11 mu_B at 90% C.L. This corresponds to the individual transition magnetic moment constraints: |Lambda_1| < 5.6 x10^-11 mu_B, |Lambda_2| < 4.0 x 10^-11 mu_B, and |Lambda_3| < 3.1 x 10^-11 mu_B (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 gl...
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.
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.
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.
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
Elastoswellability: Will it bend or will it buckle?
Holmes, Douglas; Pandey, Anupam
2013-03-01
Soft mechanical structures such as biological tissues and gels exhibit motion, instabilities, and large morphological changes when subjected to external stimuli. Swelling is a robust approach for inducing structural change as it occurs naturally in humid environments and can be easily adapted for industrial design. Small volumes of fluid that interact favorably with a material can cause large, dramatic, and geometrically nonlinear deformations including beam bending, plate buckling, and surface wrinkling. In this talk we address an overarching question regarding swelling-induced deformations: will the structural change occur globally, or will it be confined to the material's surface? We introduce a materials and geometry defined transition point that describes a fluid-structure's characteristic ``elastoswellability'' lengthscale. By locally swelling unconstrained slender beams and plates with solvents of varying solubility, we identify a transition between local surface wrinkling and global structural bending.
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
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)
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.
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.
Tunable thermoelectric properties in bended graphene nanoribbons
Chang-Ning, Pan; Jun, He; Mao-Fa, Fang
2016-07-01
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 quantum 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. Project supported by the National Natural Science Foundation of China (Grant No. 61401153) and the Natural Science Foundation of Hunan Province, China (Grant Nos. 2015JJ2050 and 14JJ3126).
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 ...
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.
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.
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...
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...
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
Yang, Peng-Fei; Sanno, Maximilian; Ganse, Bergita; Koy, Timmo; Brüggemann, Gert-Peter; Müller, Lars Peter; Rittweger, Jörn
2014-01-01
Bending, in addition to compression, is recognized to be a common loading pattern in long bones in animals. However, due to the technical difficulty of measuring bone deformation in humans, our current understanding of bone loading patterns in humans is very limited. In the present study, we hypothesized that bending and torsion are important loading regimes in the human tibia. In vivo tibia segment deformation in humans was assessed during walking and running utilizing a novel optical approach. Results suggest that the proximal tibia primarily bends to the posterior (bending angle: 0.15°-1.30°) and medial aspect (bending angle: 0.38°-0.90°) and that it twists externally (torsion angle: 0.67°-1.66°) in relation to the distal tibia during the stance phase of overground walking at a speed between 2.5 and 6.1 km/h. Peak posterior bending and peak torsion occurred during the first and second half of stance phase, respectively. The peak-to-peak antero-posterior (AP) bending angles increased linearly with vertical ground reaction force and speed. Similarly, peak-to-peak torsion angles increased with the vertical free moment in four of the five test subjects and with the speed in three of the test subjects. There was no correlation between peak-to-peak medio-lateral (ML) bending angles and ground reaction force or speed. On the treadmill, peak-to-peak AP bending angles increased with walking and running speed, but peak-to-peak torsion angles and peak-to-peak ML bending angles remained constant during walking. Peak-to-peak AP bending angle during treadmill running was speed-dependent and larger than that observed during walking. In contrast, peak-to-peak tibia torsion angle was smaller during treadmill running than during walking. To conclude, bending and torsion of substantial magnitude were observed in the human tibia during walking and running. A systematic distribution of peak amplitude was found during the first and second parts of the stance phase.
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...
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.)
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.
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.
Effect of Induction Heat Bending Process on the Properties of ASME SA106 Gr. C Carbon Steel Pipes
Energy Technology Data Exchange (ETDEWEB)
Kim, Ki Tae; Kim, Young Sik [Andong National University, Andong (Korea, Republic of); Chang, Hyun Young; Oh, Young Jin [KEPCO Engineering and Construction Company, Seongnam (Korea, Republic of); Sung, Gi Ho [R and D Center, Busan (Korea, Republic of)
2015-04-15
Recently, the bending process is greatly applied to fabricate the pipe line. Bending process can reduce welding joints and then decrease the number of inspection. Thus, the maintenance cost will be reduced. Induction heat bending process is composed of bending deformation by repeated local heat and cooling. By this thermal process, corrosion properties and microstructure can be affected. This work focused on the effect of induction heating bending process on the properties of ASME SA106 Gr. C low carbon steel pipes. Microstructure analysis, hardness measurements, and immersion corrosion test were performed for base metal and bended area including extrados, intrados, crown up, and down parts. Microstructure was analyzed using an optical microscope and SEM. Hardness was measured using a Rockwell B scale. Induction heat bending process has influenced upon the size and distribution of ferrite and pearlite phases which were transformed into finer structure than those of base metal. Even though the fine microstructure, every bent area showed a little lower hardness than that of base metal. It is considered that softening by the bending process may be arisen. Except of I2, intrados area, the others showed a similar corrosion rate to that of base metal. But even relatively high rate of intrados area was very low and acceptable. Therefore, it is judged that induction heat bending process didn't affect boric acid corrosion behaviour of carbon steel.
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.
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.
Institute of Scientific and Technical Information of China (English)
无
2005-01-01
This paper is based on the fundamental loading model of pure bending and the analytical model of a circular beam element with arbitrary initial deflection. The L.W. Guo solution is modified and generalized according to the elastic theory, and the analytical solution for the stress of the beam element with arbitrary initial deflection under pure bending is derived. Using yield theory of edge strength, an expression for the safety margin of one point in the arbitrary curved beam under pure bending (ACPB) is built. This paper modifies the model for weak points of service structures and establishes a foundation for safe design and inspection of imperfect structures. Also, according to the theory of the method of advanced first-order second-moment(AFOSM), this paper derives an expression for the reliability index of one point in ACPB. Lastly, it modifies the solution for weak points by solving the minimal reliability index.
Energy Technology Data Exchange (ETDEWEB)
Rozumek, D.; Macha, E. [Opole University of Technology, Department of Mechanics and Machine Design, Opole (Poland)
2009-10-15
The paper presents the results of tests on fatigue crack growth under proportional torsion with bending in AlCu4Mg1 aluminium alloy. Specimens with rectangular cross-sections and stress concentrator in the form of external one-sided sharp notch were used. The tests were performed under the different ratios of torsion to bending moments. The results of the experimental tests have been described by a nonlinear formula based on {delta}J-integral range. The tests have shown that the change of ratio of torsion to bending moments from 0.58 to 1.73 caused an increase in crack growth rate. It has been shown that at the constant loading and the change of stress ratio (R) from - 1 to 0, the fatigue crack growth rate also increases. (Abstract Copyright [2009], Wiley Periodicals, Inc.)
SPEECH CLASSIFICATION USING ZERNIKE MOMENTS
Directory of Open Access Journals (Sweden)
Manisha Pacharne
2011-07-01
Full Text Available Speech recognition is very popular field of research and speech classification improves the performance for speech recognition. Different patterns are identified using various characteristics or features of speech to do there classification. Typical speech features set consist of many parameters like standard deviation, magnitude, zero crossing representing speech signal. By considering all these parameters, system computation load and time will increase a lot, so there is need to minimize these parameters by selecting important features. Feature selection aims to get an optimal subset of features from given space, leading to high classification performance. Thus feature selection methods should derive features that should reduce the amount of data used for classification. High recognition accuracy is in demand for speech recognition system. In this paper Zernike moments of speech signal are extracted and used as features of speech signal. Zernike moments are the shape descriptor generally used to describe the shape of region. To extract Zernike moments, one dimensional audio signal is converted into two dimensional image file. Then various feature selection and ranking algorithms like t-Test, Chi Square, Fisher Score, ReliefF, Gini Index and Information Gain are used to select important feature of speech signal. Performances of the algorithms are evaluated using accuracy of classifier. Support Vector Machine (SVM is used as the learning algorithm of classifier and it is observed that accuracy is improved a lot after removing unwanted features.
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
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....... The forward bending of ≥30° was computed from accelerometer recordings for several consecutive days during work, categorized into long (highest tertile) and short-moderate (remaining tertiles) duration. LBPi was measured on a 0-10 scale and categorized into low (≤5) and high (>5) pain. Self-reported social....... 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, workers...
Nickel multilayers and their effects on bend fatigue strength of leads
Institute of Scientific and Technical Information of China (English)
LIU Feihua; WANG Zhanhua; SHEN Zhuoshen
2004-01-01
Nickel is commonly coated on the outer leads for T8 metal package. The leads electrodeposited by conventional dull or bright nickel over 5 μm at direct current from Watt bath are hard to pass the bend fatigue test for three times. Nickel electrodeposited at multi waveform current including direct current, single and double pulse from sulfamate bath can improve the bend fatigue strength of leads. Such nickel plating has a multilayer structure, its morphology of sublayers can be clearly seen in its cross section with SEM. The electrochemical study shows that these sublayers have different corrosion potentials. The bend fatigue test of leads with such plating for T8 metal package shows that the number of bend increases with the decrease of average current density of multi waveform, which can be attributed to the reduction of every sublayer thickness and the increase of layer numbers under the same condition of total thickness.
Bozzini, Clarisa; Champin, Graciela; Alippi, Rosa M; Bozzini, Carlos E
2015-04-01
Long-term glucocorticoid administration to growing rats induces osteopenia and alterations in the biomechanical behavior of the bone. This study was performed to estimate the effects of dexamethasone (DTX), a synthetic steroid with predominant glucocorticoid activity, on the biomechanical properties of the mandible of rats during the growth phase, as assessed by bending test and peripheral quantitative computed tomographic (pQCT) analysis. The data obtained by the two methods will provide more precise information when analyzed together than separately. Female rats aged 23 d (n=7) received 500μg.kg-1 per day of DXT for 4 weeks. At the end of the treatment period, their body weight and body length were 51.3% and 20.6% lower, respectively, than controls. Hemimandible weight and area (an index of mandibular size) were 27.3% and 9.7% lower, respectively. The right hemimandible of each animal was subjected to a mechanical 3-point bending test. Significant weakening of the bone, as shown by a correlative impairment of strength and stiffness, was observed in experimental rats. Bone density and cross-sectional area were measured by pQCT. Cross-sectional, cortical and trabecular areas were reduced by 20% to 30% in the DTX group, as were other cortical parameters, including the bone density, mineral content and cross-sectional moment of inertia. The "bone strength index" (BSI, the product of the pQCT-assessed xCSMI and vCtBMD) was 56% lower in treated rats, which compares well with the 54% and 52% reduction observed in mandibular strength and stiffness determined through the bending test. Data suggest that the corticosteroid exerts a combined, negative action on bone geometry (mass and architecture) and volumetric bone mineral density of cortical bone, which would express independent effects on both cellular (material quality) and tissue (cross-sectional design) levels of biological organization of the skeleton in the species.
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.
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.
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...
Inelastic Deformation Analysis of Aluminum Bending Members
Institute of Scientific and Technical Information of China (English)
CHENG Ming; SHI Yongjiu; WANG Yuanqing
2006-01-01
Aluminum alloys are typical nonlinear materials, and consequently bending members made of this material exhibit a nonlinear behavior. Most design codes do not pay much attention to such deformations and adopt a simple linear analysis for the calculation of deflections. This paper presents an investigation of the nonlinear deformation of aluminum bending members using the finite-element analysis (FEA). The plastic adaptation coefficient, which can be used to limit the residual deflection, is introduced, and the influence of residual deflection is investigated. A method for evaluating the plastic adoption coefficient is proposed. This paper also shows the load-deflection curve of aluminum bending members and the influence of several parameters. A semi-empirical formula is derived, and some numerical examples are given by FEA. The coefficients of the semi-empirical formula are modified by the FEA results using the nonlinear fitting method. Based on these results, two improved design methods for strength and deformation of aluminum bending members are proposed. Through the comparison with test data, these methods are proved to be suitable for structural design.
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.
Axisymmetric bending oscillations of stellar disks
Sellwood, J A
1996-01-01
Self-gravitating stellar disks with random motion support both exponentially growing and, in some cases, purely oscillatory axisymmetric bending modes, unlike their cold disk counterparts. A razor-thin disk with even a very small degree of random motion in the plane is both unstable and possesses a discrete spectrum of neutral modes, irrespective of the sharpness of the edge. Random motion normal to the disk plane has a stabilizing effect but at the same time allows bending waves to couple to the internal vibrations of the particles, which causes the formerly neutral modes to decay through Landau damping. Focusing first on instabilities, I here determine the degree of random motion normal to the plane needed to suppress global, axisymmetric, bending instabilities in a family of self-gravitating disks. As found previously, bending instabilities are suppressed only when the thickness exceeds that expected from a na\\"\\i ve local criterion when the degree of pressure support within the disk plane is comparable to...
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.
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.
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.
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.
Nuclear Quadrupole Moments and Nuclear Shell Structure
Townes, C. H.; Foley, H. M.; Low, W.
1950-06-23
Describes a simple model, based on nuclear shell considerations, which leads to the proper behavior of known nuclear quadrupole moments, although predictions of the magnitudes of some quadrupole moments are seriously in error.
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.
Symmetric bends how to join two lengths of cord
Miles, Roger E
1995-01-01
A bend is a knot securely joining together two lengths of cord (or string or rope), thereby yielding a single longer length. There are many possible different bends, and a natural question that has probably occurred to many is: "Is there a 'best' bend and, if so, what is it?"Most of the well-known bends happen to be symmetric - that is, the two constituent cords within the bend have the same geometric shape and size, and interrelationship with the other. Such 'symmetric bends' have great beauty, especially when the two cords bear different colours. Moreover, they have the practical advantage o
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.
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 ...
On the interpretation of the support moment
Hof, AL
2000-01-01
It has been suggested by Winter (J. Biomech. 13 (1980) 923-927) that the 'support moment', the sum of the sagittal extension moments, shows less variability in walking than any of the joint moments separately. A simple model is put forward to explain this finding. It is proposed to reformulate the d
Finite Element Analysis for Bending Process of U-Bending Specimens
Energy Technology Data Exchange (ETDEWEB)
Park, Won Dong; Bahn, Chi Bum [Pusan National University, Busan (Korea, Republic of)
2015-10-15
ASTM G30 suggests that the applied strain can be calculated by dividing thickness by a bend radius. It should be noted, however, that the formula is reliable under an assumption that the ratio of thickness to bend radius is less than 0.2. Typically, to increase the applied stress/strain, the ratio of thickness to bend radius becomes larger than 0.2. This suggests that the estimated strain values by ASTM G30 are not reliable to predict the actual residual strain state of the highly deformed U-bend specimen. For this reason, finite element analysis (FEA) for the bending process of Ubend specimens was conducted by using a commercial finite element analysis software ABAQUS. ver.6.14- 2;2014. From the results of FEA, PWSCC initiation time and U-bend specimen size can be determined exactly. Since local stress and strain have a significant effect on the initiation of PWSCC, it was inappropriate to apply results of ASTM G30 to the PWSCC test directly. According to results of finite element analysis (FEA), elastic relaxation can cause inaccuracy in intended final residual stress. To modify this inaccuracy, additional process reducing the spring back is required. However this additional process also may cause uncertainty of stress/strain state. Therefore, the U-bending specimen size which is not creating uncertainty should be optimized and selected. With the bending radius of 8.3 mm, the thickness of 3 mm and the roller distance of 32.6 mm, calculated maximum stress and strain were 670 MPa and 0.21, respectively.
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.
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 ...
Experimental review on moment analyses
Calvi, M
2003-01-01
Moments of photon energy spectrum in B->Xs gamma decays, of hadronic mass spectrum and of lepton energy spectrum in B->Xc l nu decays are sensitive to the masses of the heavy quarks as well as to the non-perturbative parameters of the heavy quark expansion. Several measurements have been performed both at the Upsilon(4S) resonance and at Z0 center of mass energies. They provide constraints on the non-perturbative parameters, give a test of the consistency of the theoretical predictions and of the underlying assumptions and allow to reduce the indetermination in the |Vcb| extraction.
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.
Geologic map of Big Bend National Park, Texas
Turner, Kenzie J.; Berry, Margaret E.; Page, William R.; Lehman, Thomas M.; Bohannon, Robert G.; Scott, Robert B.; Miggins, Daniel P.; Budahn, James R.; Cooper, Roger W.; Drenth, Benjamin J.; Anderson, Eric D.; Williams, Van S.
2011-01-01
The purpose of this map is to provide the National Park Service and the public with an updated digital geologic map of Big Bend National Park (BBNP). The geologic map report of Maxwell and others (1967) provides a fully comprehensive account of the important volcanic, structural, geomorphological, and paleontological features that define BBNP. However, the map is on a geographically distorted planimetric base and lacks topography, which has caused difficulty in conducting GIS-based data analyses and georeferencing the many geologic features investigated and depicted on the map. In addition, the map is outdated, excluding significant data from numerous studies that have been carried out since its publication more than 40 years ago. This report includes a modern digital geologic map that can be utilized with standard GIS applications to aid BBNP researchers in geologic data analysis, natural resource and ecosystem management, monitoring, assessment, inventory activities, and educational and recreational uses. The digital map incorporates new data, many revisions, and greater detail than the original map. Although some geologic issues remain unresolved for BBNP, the updated map serves as a foundation for addressing those issues. Funding for the Big Bend National Park geologic map was provided by the United States Geological Survey (USGS) National Cooperative Geologic Mapping Program and the National Park Service. The Big Bend mapping project was administered by staff in the USGS Geology and Environmental Change Science Center, Denver, Colo. Members of the USGS Mineral and Environmental Resources Science Center completed investigations in parallel with the geologic mapping project. Results of these investigations addressed some significant current issues in BBNP and the U.S.-Mexico border region, including contaminants and human health, ecosystems, and water resources. Funding for the high-resolution aeromagnetic survey in BBNP, and associated data analyses and
fMRI-compatible registration of jaw movements using a fiber-optic bend sensor
Directory of Open Access Journals (Sweden)
Peter Sörös
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.
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. ...
A preliminary bending fatigue spectrum for steel monostrand cables
DEFF Research Database (Denmark)
Winkler, Jan; Fischer, Gregor; Georgakis, Christos T.;
2011-01-01
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...
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.
Time invariance violating nuclear electric octupole moments
Flambaum, V V; Orton, S R
1997-01-01
The existence of a nuclear electric octupole moment (EOM) requires both parity and time invariance violation. The EOMs of odd $Z$ nuclei that are induced by a particular T- and P-odd interaction are calculated. We compare such octupole moments with the collective EOMs that can occur in nuclei having a static octupole deformation. A nuclear EOM can induce a parity and time invariance violating atomic electric dipole moment, and the magnitude of this effect is calculated. The contribution of a nuclear EOM to such a dipole moment is found, in most cases, to be smaller than that of other mechanisms of atomic electric dipole moment production.
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...
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.
Moment-to-moment dynamics of ADHD behaviour
Directory of Open Access Journals (Sweden)
Aase Heidi
2005-08-01
learning long behavioural sequences may ultimately lead to deficient development of verbally governed behaviour and self control. The study represents a new approach to analyzing the moment-to-moment dynamics of behaviour, and provides support for the theory that reinforcement processes are altered in ADHD.
Thermal Analysis of Bending Under Tension Test
DEFF Research Database (Denmark)
Ceron, Ermanno; Martins, Paulo A.F.; Bay, Niels
2014-01-01
during testing is similar to the one in the production tool. A universal sheet tribo-tester has been developed, which can run multiple tests automatically from coil. This allows emulating the temperature increase as in production. The present work performs finite element analysis of the evolution...... and distribution of temperature in the bending under tension test by making use of boundary conditions and calibration values directly measured from experiments. The overall methodology combines 2D and 3D models of the bending under tension test with steady state and transient thermal and thermo......-mechanical procedures. Results show that the proposed methodology applied to a single stroke can effectively and accurately predict the interface temperature in the test tool, thus avoiding the otherwise required thousands of thermo-mechanical FEM analyses of temperature development during testing before thermal steady...
Rock bending creep and disturbance effects
Institute of Scientific and Technical Information of China (English)
付志亮; 郑颖人; 刘元雪
2008-01-01
The bending creep and its disturbance effects of red sandstone rock beam and oil shale rock beam were studied by adopting the self-developed gravitation level style rock creep test machine and bending creep test system,and the constitutive equations were established.It is found that fracture morphology of rock beams under no disturbance load is regular,cracking position of fractures is on part of loading concentration,the crack starts from a neutral plane.However,fracture morphology of rock beams under disturbance load is irregular,cracking position of fractures deviates from a neutral plane.Delayed instability of rock beam occurs for some time under constant disturbance load.When disturbance load is beyond a certain range,suddenly instability of occurs rock beam in a certain time.The results show that there is a guiding significance for creep stability in the geotechnical engineering fields.
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.
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.
Parallel monostrand stay cable bending fatigue
DEFF Research Database (Denmark)
Winkler, Jan Pawel
This dissertation investigates the bending fatigue response of high-strength steel monostrands and multistrand stay cables to cyclic transverse deformations. Increasing bridge stock numbers and a push for longer cable-supported span lengths have led to an increased number of reported incidents...... of damage and replacement of bridge stay cables due to wind and traffic-induced fatigue. The understanding of fatigue mechanisms in most steel structures is well established. However, in the case of cables composed of steel strands, many important aspects related with bending fatigue remain to be clarified....... The thesis starts with a literature review of the state-of-the-art in the fields of stay cable fatigue testing and cable fatigue resistance. The study helped to systemize the understanding of the fatigue characteristics of bridge cables subjected to cyclic transverse displacements, failure mechanisms...
Hydrodynamic processes in sharp meander bends and their morphological implications
Blanckaert, K.
2011-01-01
The migration rate of sharp meander bends exhibits large variance and indicates that some sharply curved bends tend to stabilize. These observations remain unexplained. This paper examines three hydrodynamic processes in sharp bends with fixed banks and discusses their morphological implications: se
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
Electron cooling device without bending magnets
Sharapa, A. N.; Shemyakin, A. V.
1993-11-01
The scheme of an axisymmetric electron cooling device without bending magnets is proposed. Solutions for the most important elements, i.e., a gun and a recuperator, are considered. The main characteristics of the recuperator of the Faraday cup type having a reflector and a gun with a ring emitter are explored. In the gun, the beam is formed, the diameter of which is 40 mm and the dimension of a disturbance region is several millimeters.
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.
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.
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...
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...
Breather statics and dynamics in Klein-Gordon chains with a bend.
Cuevas, J; Kevrekidis, P G
2004-05-01
In this paper, we examine a nonlinear model with an impurity emulating a bend. We justify the geometric interpretation of the model and connect it with earlier work on models including geometric effects. We focus on both the bifurcation and stability analysis of the modes that emerge as a function of the strength of the bend angle, but we also examine dynamical effects including the scattering of mobile localized modes (discrete breathers) off of such a geometric structure. The potential outcomes of such numerical experiments (including transmission, trapping within the bend as well as reflection) are highlighted and qualitatively explained. Such models are of interest both theoretically in understanding the interplay of breathers with curvature, but also practically in simple models of photonic crystals or of bent chains of DNA.
Institute of Scientific and Technical Information of China (English)
彭利平; 刘初升; 宋宝成; 武继达; 王帅
2015-01-01
Demand for large vibrating screen is huge in the mineral processing industry. As bending and random vibration are not considered in a traditional design method for beam structures of a large vibrating screen, fatigue damage occurs frequently to affect the screening performance. This work aims to conduct a systematic mechanics analysis of the beam structures and improve the design method. Total motion of a beam structure in screening process can be decomposed into the traditional followed rigid translation (FRT), bending vibration (BV) and axial linear-distributed random rigid translation (ALRRT) excited by the side-plates. When treated as a generalized single-degree-of-freedom (SDOF) elastic system analytically, the BV can be solved by the Rayleigh’s method. Stochastic analysis for random process is conducted for the detailed ALRRT calculation. Expressions for the mechanics property, namely, the shearing force and bending-moment with respect to BV and ALRRT, are derived, respectively. Experimental and numerical investigations demonstrate that the largest BV exists at the beam center and can be nearly ignored in comparison with the FRT during a simplified engineering design. With the BV and FRT considered, the mechanics property accords well with the practical situation with the maximum error of 6.33%, which is less than that obtained by traditional method.
2011-12-29
... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY 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...
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.
On the bending algorithms for soft objects in flows
Guckenberger, Achim; Schraml, Marcel P.; Chen, Paul G.; Leonetti, Marc; Gekle, Stephan
2016-10-01
One of the most challenging aspects in the accurate simulation of three-dimensional soft objects such as vesicles or biological cells is the computation of membrane bending forces. The origin of this difficulty stems from the need to numerically evaluate a fourth order derivative on the discretized surface geometry. Here we investigate six different algorithms to compute membrane bending forces, including regularly used methods as well as novel ones. All are based on the same physical model (due to Canham and Helfrich) and start from a surface discretization with flat triangles. At the same time, they differ substantially in their numerical approach. We start by comparing the numerically obtained mean curvature, the Laplace-Beltrami operator of the mean curvature and finally the surface force density to analytical results for the discocyte resting shape of a red blood cell. We find that none of the considered algorithms converges to zero error at all nodes and that for some algorithms the error even diverges. There is furthermore a pronounced influence of the mesh structure: Discretizations with more irregular triangles and node connectivity present serious difficulties for most investigated methods. To assess the behavior of the algorithms in a realistic physical application, we investigate the deformation of an initially spherical capsule in a linear shear flow at small Reynolds numbers. To exclude any influence of the flow solver, two conceptually very different solvers are employed: the Lattice-Boltzmann and the Boundary Integral Method. Despite the largely different quality of the bending algorithms when applied to the static red blood cell, we find that in the actual flow situation most algorithms give consistent results for both hydrodynamic solvers. Even so, a short review of earlier works reveals a wide scattering of reported results for, e.g., the Taylor deformation parameter. Besides the presented application to biofluidic systems, the investigated
Optical guiding and beam bending in free-electron lasers
Energy Technology Data Exchange (ETDEWEB)
Scharlemann, E.T.
1987-01-01
The electron beam in a free-electron laser (FEL) can act as an optical fiber, guiding or bending the optical beam. The refractive and gain effects of the bunched electron beam can compensate for diffraction, making possible wigglers that are many Rayleigh ranges (i.e., characteristic diffraction lengths) long. The origin of optical guiding can be understood by examining gain and refractive guiding in a fiber with a complex index of refraction, providing a mathematical description applicable also to the FEL, with some extensions. In the exponential gain regime of the FEL, the electron equations of motion must be included, but a self-consistent description of exponential gain with diffraction fully included becomes possible. The origin of the effective index of refraction of an FEL is illustrated with a simple example of bunched, radiating dipoles. Some of the properties of the index of refraction are described. The limited experimental evidence for optical beam bending is summarized. The evidence does not yet provide conclusive proof of the existence of optical guiding, but supports the idea. Finally, the importance of refractive guiding for the performance of a high-gain tapered-wiggler FEL amplifier is illustrated with numerical simulations.
Moment methods for coagulation, breakage and coalescence problems
Diemer, Russell Bertrum, Jr.
This work advances the art of modeling coagulation, breakage and coalescence of agglomerated particles. Such models apply to industrial particle processing unit operations and their analogs (e.g., polymerization and depolymerization). Direct calculation of particle-size distribution evolution proceeds by a division of the size spectrum into many small sections. The computing resources required preclude coupling this approach with detailed equipment piece or process flowsheet simulations. Conventional moment models are computationally less demanding, but sacrifice distribution detail. In this work, a moment approach is developed which restores that lost detail, and includes: (1) a closure rule for solving the general dynamic moment problem, (2) basis sets upon which to reconstruct the distributions from the moment solutions, and (3) a technique to guide the reconstruction. The basis sets are founded upon a new, general class of distribution functions which contains many of the familiar distribution functions. Coalescence alters an agglomerate's surface area without changing its volume. In addition, the coalescence time scale may differ from those characteristic of the volume-altering processes of coagulation and breakage. For these reasons, a single distribution variable (e.g., volume) is generally inadequate to describe coalescing populations. In this work, a bivariate formulation is developed which casts the particle distribution as the product of a marginal distribution in volume and a volume-conditional distribution in surface area. Reconstruction of the full bivariate distribution hinges on a relationship between the bivariate moments and the conditional area moments. These developments are facilitated by a generalization of breakage daughter distributions, and the discernment of bivariate breakage types, leading to the specification of bivariate daughter distributions. Insight toward the moment methodology comes from approximate analytical steady
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)
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}
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.
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......, shown that previous proofs of this result are incorrect. The main result of this paper is based on geometric inequalities in Gauss space and on a generalization of the Krein criterion due to H. L. Pedersen....
Fox-Wolfram Moments in Higgs Physics
Bernaciak, Catherine; Butter, Anja; Plehn, Tilman
2012-01-01
Geometric correlations between jets as part of hard processes or in addition to hard processes are key ingredients to many LHC analyses. Fox--Wolfram moments systematically describe these correlations in terms of spherical harmonics. These moments, either computed from the tagging jets or from all jets in each event, can significantly improve Higgs searches in weak boson fusion. Applications of Fox--Wolfram moments in LHC analyses obviously surpass jets as analysis objects as well as Higgs searches in terms of analyses.
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...
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
Latham, J.P.; Xiang, J.; Belayneh, M.; Nick, H.M.; Tsang, C.F.; Blunt, M.J.
2013-01-01
The influence of in-situ stresses on flow processes in fractured rock is investigated using a novel modelling approach. The combined finite-discrete element method (FEMDEM) is used to model the deformation of a fractured rock mass. The fracture wall displacements and aperture changes are modelled in
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
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.
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
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.
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.
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.
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.
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.
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.
Secondary turbulent flow in an infinte bend
DEFF Research Database (Denmark)
Christensen, H. Bo; Gislason, Kjartan; Fredsøe, Jørgen
1999-01-01
The flow in an infinite circular bend is inverstigated in both the laminar and fully turbulent flow case, by use of laminar flow solver, a k-e turbulence model, and a fully Reynolds stress turbulence model. The topic of the analysis is to investigate whether a counter-rotating secondary flow cell...... model, the influence of the curvature ratio and cross section geometry on the vortex pattern is investigated. Furthermore, it is demonstrated that an-isotropy of turbulence plays an important role for the structure of flow pattern and existence of an extra flow cell....
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.
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.
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 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 ...
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.
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.
Boone, David A; Kobayashi, Toshiki; Chou, Teri G; Arabian, Adam K; Coleman, Kim L; Orendurff, Michael S; Zhang, Ming
2013-04-01
Alignment - the process and measured orientation of the prosthetic socket relative to the foot - is important for proper function of a transtibial prosthesis. Prosthetic alignment is performed by prosthetists using visual gait observation and amputees' feedback. The aim of this study was to investigate the effect of transtibial prosthesis malalignment on the moments measured at the base of the socket: the socket reaction moments. Eleven subjects with transtibial amputation were recruited from the community. An instrumented prosthesis alignment component was used to measure socket reaction moments during ambulation under 17 alignment conditions, including nominally aligned using conventional clinical methods, and angle perturbations of 3° and 6° (flexion, extension, abduction, and adduction) and translation perturbations of 5mm and 10mm (anterior, posterior, lateral, and medial) referenced from the nominal alignment. Coronal alignment perturbations caused systematic changes in the coronal socket reaction moments. All angle and translation perturbations revealed statistically significant differences on coronal socket reaction moments compared to the nominal alignment at 30% and 75% of stance phase (Psocket reaction moments was not as responsive as that of the coronal perturbations. The sagittal angle and translation perturbations of the socket led to statistically significant changes in minimum moment, maximum moment, and moments at 45% of stance phase in the sagittal plane. Therefore, malalignment affected the socket reaction moments in amputees with transtibial prostheses.
Recursive Sketching For Frequency Moments
Braverman, Vladimir
2010-01-01
In a ground-breaking paper, Indyk and Woodruff (STOC 05) showed how to compute $F_k$ (for $k>2$) in space complexity $O(\\mbox{\\em poly-log}(n,m)\\cdot n^{1-\\frac2k})$, which is optimal up to (large) poly-logarithmic factors in $n$ and $m$, where $m$ is the length of the stream and $n$ is the upper bound on the number of distinct elements in a stream. The best known lower bound for large moments is $\\Omega(\\log(n)n^{1-\\frac2k})$. A follow-up work of Bhuvanagiri, Ganguly, Kesh and Saha (SODA 2006) reduced the poly-logarithmic factors of Indyk and Woodruff to $O(\\log^2(m)\\cdot (\\log n+ \\log m)\\cdot n^{1-{2\\over k}})$. Further reduction of poly-log factors has been an elusive goal since 2006, when Indyk and Woodruff method seemed to hit a natural "barrier." Using our simple recursive sketch, we provide a different yet simple approach to obtain a $O(\\log(m)\\log(nm)\\cdot (\\log\\log n)^4\\cdot n^{1-{2\\over k}})$ algorithm for constant $\\epsilon$ (our bound is, in fact, somewhat stronger, where the $(\\log\\log n)$ term c...
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
Microwave spectrum, structure, dipole moment, and Coriolis coupling of 1,1-difluoroallene
Durig, J. R.; Li, Y. S.; Tong, C. C.; Zens, A. P.; Ellis, P. D.
1974-01-01
Microwave spectra from 12.4 to 40.0 GHz were recorded for five isotopic species of 1,1-difluoroallene. A-type transitions were observed and R-branch assignments were made for the ground state and two vibrationally excited states. Several structural parameters of the compounds were determined. The dipole moment value obtained from Stark splitting was 2.07 plus or minus 0.03 D. A Coriolis coupling was observed between the two-low-frequency C = C = C bending modes.
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.
Effects of stem structure and cell wall components on bending strength in wheat
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
Morphological traits, anatomical features, chemical components and bending stress in the stems of three genotypes of wheat (Triticum aestivum L.), namely Xiaoyan54, 8602 and Xiaoyan81, were examined by means of light microscopy coupled with Fourier transform infrared spectroscopy (FTIR). Noticeable changes in morphological and anatomical traits were observed, including outer radius of stem, the ratio of stem outer radius to stem wall thickness, various tissue proportions and variations among different types of vascular bundles. The results of chemical analysis revealed that Xiaoyan81 had the highest cellulose content in comparison with Xiaoyan54 and 8602, whereas lignin level in Xiaoyan81 was lower than that in 8602 but higher that that in Xiaoyan54. Bending stress analysis demonstrated that Xiaoyan81 may be the main target for identification, for it had the highest bending stress among the stems of three genotypes. Associated with bending stress, all the results presented here suggested that the ratio of stem wall thickness to its outer radius, schlerenchyma tissue proportion, the average number of big VB per unit and the cellulose content are four important factors affecting the mechanical strength of Xiaoyan81 wheat stems, which can be considered as the key parameters for selecting varieties with bending stress. Therefore, it was suggested that in the selection of lodging resistant cultivars one should consider those characterized with large ratio of outer radius of stem to stem wall thickness, greaterschlerenchyma tissue proportion, high average number of big VB per unit with high cellulose content in their stems.
Electrostatic model of the energy-bending within organic semiconductors: experiment and simulation
Whitcher, T. J.; Wong, W. S.; Talik, A. N.; Woon, K. L.; Chanlek, N.; Nakajima, H.; Saisopa, T.; Songsiriritthigul, P.
2016-09-01
The interfacial properties between electrodes and the various organic layers that comprise an organic electronic device are of direct relevance in understanding charge injection, extraction and generation. The energy levels and energy-bending of three interfaces; indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), ITO/poly(N-vinylcarbazole) (PVK) and PEDOT:PSS/PVK were measured using ultraviolet photoelectron spectroscopy (UPS) and x-ray photoelectron spectroscopy (XPS). By decoupling the vacuum shift and energy-bending, the energy-bending at these interfaces can be simulated using an electrostatic model that takes into account the energetic disorder of the polymers. The model is further extended to include blended mixtures of semiconductors at differing concentrations and it was found that a very good agreement exists between the experiment and theory for all interfaces. This suggests that the electrostatic model can be used to describe energy-bending at the interface between any organic semiconductors. Further investigation into the effect of the Gaussian density of states width on energy-bending is warranted.
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
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.
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…
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…
Spin and orbital moments in actinide compounds
DEFF Research Database (Denmark)
Lebech, B.; Wulff, M.; Lander, G.H.
1991-01-01
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...
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)
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.
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
Effects of texture on shear band formation in plane strain tension/compression and bending
DEFF Research Database (Denmark)
Kuroda, M.; Tvergaard, Viggo
2007-01-01
In this study, effects of typical texture components observed in rolled aluminum alloy sheets on shear band formation in plane strain tension/compression and bending are systematically studied. The material response is described by a generalized Taylor-type polycrystal model, in which each grain...... model analysis. Third, shear band developments in plane strain pure bending of a sheet specimen with the typical textures are studied. Regions near the surfaces in a bent sheet specimen are approximately subjected to plane strain tension or compression. From this viewpoint, the bendability of a sheet...... specimen may be evaluated, using the knowledge regarding shear band formation in plane strain tension/compression. To confirm this and to encompass overall deformation of a bent sheet specimen, including shear bands, finite element analyses of plane strain pure bending are carried out, and the predicted...
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
Wang, Hong; Wang, Jy-An John
2016-10-01
Behavior of surrogate nuclear fuel rods made of Zircaloy-4 (Zry-4) cladding with alumina pellets under reversed cyclic bending was studied. Tests were performed under load or moment control at 5 Hz. The surrogate rods fractured under moment amplitudes greater than 10.16 Nm with fatigue lives between 2.4 × 103 and 2.2 × 106 cycles. Fatigue response of Zry-4 cladding was characterized by using flexural rigidity. Degradation of flexural rigidity was shown to depend on the moment and the prefatigue condition of specimens. Pellet-to-pellet interface (PPI), pellet-to-cladding interface (PCI), and pellet condition affect surrogate rod failure. Both debonding of PPI/PCI and pellet fracturing contribute to surrogate rod bending fatigue. The effect of sensor spacing on curvature measurement using three-point deflections was studied; the method based on effective gauge length is effective in sensor spacing correction. The database developed and the understanding gained in this study can serve as input to analysis of SNF (spent nuclear fuel) vibration integrity.
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.
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)
Flexible bending of aluminum profiles with polyurethane pad
Institute of Scientific and Technical Information of China (English)
HE Zhu-bin; LIU Gang; WANG Zhong-ren
2006-01-01
The high flexibility of profile bending with hyperelastic pad enables it to be a promising method for small lot or single part production, especially for space frame and roof-rail parts in automotive and aerospace industries. Bending of two aluminum profiles with different sections was carried out to investigate the effect of main process parameters on the bending process. Results show that the shape of the cross-section and its relative thickness and section modulus in bending are the main factors that determine the bending properties of the profiles. Roller stroke, properties of polyurethane pad and constraints on profiles are key factors that determine the bending radius and section deformation of bent profiles. Failures and quality problems met in experiments were also analyzed.
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%.
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.
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)...
BEND3 mediates transcriptional repression and heterochromatin organization.
Khan, Abid; Prasanth, Supriya G
2015-01-01
Transcription repression plays a central role in gene regulation. Transcription repressors utilize diverse strategies to mediate transcriptional repression. We have recently demonstrated that BEND3 (BANP, E5R and Nac1 domain) protein represses rDNA transcription by stabilizing a NoRC component. We discuss the role of BEND3 as a global regulator of gene expression and propose a model whereby BEND3 associates with chromatin remodeling complexes to modulate gene expression and heterochromatin organization.
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...
Earthworm populations were surveyed in soils from a variety of habitats associated with the Hornsby Bend Biosolids Management Plant, Austin, Texas, from November 2009 through March 2010. Seven species of terrestrial Oligochaeta, including one species new to science, are reported from two families, ...
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
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.
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.
Metric of a Slow Rotating Body with Quadrupole Moment from the Erez-Rosen Metric
Frutos-Alfaro, Francisco; Cordero-García, Iván; Ulloa-Esquivel, Oscar
2012-01-01
A metric representing a slow rotating object with quadrupole moment is obtained using the Newman-Janis formalism to include rotation into the weak limit of the Erez-Rosen metric. This metric is intended to tackle relativistic astrometry and gravitational lensing problems in which a quadrupole moment has to be taken into account.
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.
PERMEABILITY OF SALTSTONE MEASUREMENT BY BEAM BENDING
Energy Technology Data Exchange (ETDEWEB)
Harbour, J; Tommy Edwards, T; Vickie Williams, V
2008-01-30
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{sup -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
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 loss in surface plasmon polariton band-gap structures
DEFF Research Database (Denmark)
Bozhevolnyi, S.I.; Volkov, V.S.; Leosson, Kristjan;
2001-01-01
Using near-field optical microscopy, we investigate propagation of surface plasmon polaritons (SPPs) excited in the wavelength range of 720-830 nm at a corrugated gold-film surface with areas of 200-nm-wide and 45-nm-high scatterers arranged in a 410-nm-period triangular lattice containing line...... defects with double bends. We find that, for similar to2-mum-wide line defects and the wavelength of similar to 740 nm, the double bend losses for bend angles of 15 degrees and 30 degrees are below 2 and 10 dB, respectively. Our data indicate that the bend loss increases approximately quadratically...
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...
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
Moment closure in a Moran model with recombination
Baake, Ellen
2011-01-01
We extend the Moran model with single-crossover recombination to include general recombination and mutation. We show that, in the case without resampling, the expectations of products of marginal processes defined via partitions of sites form a closed hierarchy, which is exhaustively described by a finite system of differential equations. One thus has the exceptional situation of moment closure in a nonlinear system. Surprisingly, this property is lost when resampling (i.e., genetic drift) is included.
Energy Technology Data Exchange (ETDEWEB)
Kim, Nam In; Kim, Young Sik [Andong National University, Andong (Korea, Republic of); Kim, Kyung Soo; Chang, Hyun Young; Park, Heung Bae; Sung, Gi Ho [KEPCO Engineering and Construction Company, Seongnam (Korea, Republic of); Sung, Gi Ho [R and D Center, Busan (Korea, Republic of)
2015-06-15
The usage of bending products recently have increased since many industries such as automobile, aerospace, shipbuilding, and chemical plants need the application of pipings. Bending process is one of the inevitable steps to fabricate the facilities. Induction heat bending is composed of compressive bending process by local heating and cooling. This work focused on the effect of induction heat bending process on the properties of ASME SA312 Gr. TP304 stainless steel pipes. Tests were performed for base metal and bended area including extrados, intrados, crown up, and down parts. Microstructure was analyzed using an optical microscope and SEM. In order to determine intergranular corrosion resistance, Double Loop Electrochemical Potentiokinetic Reactivation (DL-EPR) test and ASTM A262 practice A and C tests were done. Every specimen revealed non-metallic inclusion free under the criteria of 1.5i of the standard and the induction heat bending process did not affect the non-metallic inclusion in the alloys. Also, all the bended specimens had finer grain size than ASTM grain size number 5 corresponding to the grain sizes of the base metal and thus the grain size of the pipe bended by induction heat bending process is acceptable. Hardness of transition start, bend, and transition end areas of ASME SA312 TP304 stainless steel was a little higher than that of base metal. Intergranular corrosion behavior was determined by ASTM A262 practice A and C and DL-EPR test, and respectively step structure, corrosion rate under 0.3 mm/y, and Degree of Sensitization (DOS) of 0.001 - 0.075 % were obtained. That is, the induction heat bending process didn't affect the intergranular corrosion behavior of ASME SA312 TP304 stainless steel.
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.
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.
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.
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)
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
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).
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.
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.
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.
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.
Making Knowledge Actionable: Three Key Translation Moments
Directory of Open Access Journals (Sweden)
John R. Austin
2013-12-01
Full Text Available Leaders regularly experience pressure to move innovation and change initiatives through their organizations. They face the challenge of transforming organizational changes and innovations from ideas into sustained behavior. In this commentary, I argue that successful implementation requires leaders to engage in a translation process that contains three key translation “moments”. The challenges presented by these translation moments are magnified by the difficulty leaders often have in shifting from one moment to the next. Techniques for handling each translation moment are discussed.
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...
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.
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.
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
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
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
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.
A Moment Matching Approach for Generating Synthetic Data.
Bogle, Brittany Megan; Mehrotra, Sanjay
2016-09-01
Synthetic data are becoming increasingly important mechanisms for sharing data among collaborators and with the public. Multiple methods for the generation of synthetic data have been proposed, but many have short comings with respect to maintaining the statistical properties of the original data. We propose a new method for fully synthetic data generation that leverages linear and integer mathematical programming models in order to match the moments of the original data in the synthetic data. This method has no inherent disclosure risk and does not require parametric or distributional assumptions. We demonstrate this methodology using the Framingham Heart Study. Existing synthetic data methods that use chained equations were compared with our approach. We fit Cox proportional hazards, logistic regression, and nonparametric models to synthetic data and compared with models fitted to the original data. True coverage, the proportion of synthetic data parameter confidence intervals that include the original data's parameter estimate, was 100% for parametric models when up to four moments were matched, and consistently outperformed the chained equations approach. The area under the curve and accuracy of the nonparametric models trained on synthetic data marginally differed when tested on the full original data. Models were also trained on synthetic data and a partition of original data and were tested on a held-out portion of original data. Fourth-order moment matched synthetic data outperformed others with respect to fitted parametric models but did not always outperform other methods with fitted nonparametric models. No single synthetic data method consistently outperformed others when assessing the performance of nonparametric models. The performance of fourth-order moment matched synthetic data in fitting parametric models suggests its use in these cases. Our empirical results also suggest that the performance of synthetic data generation techniques, including the
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 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.
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.
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
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
Magnetic moments in graphene with vacancies.
Chen, Jing-Jing; Wu, Han-Chun; Yu, Da-Peng; Liao, Zhi-Min
2014-08-01
Vacancies can induce local magnetic moments in graphene, paving the way to make magnetic functional graphene. Due to the interaction between magnetic moments and conduction carriers, the magnetotransport properties of graphene can be modulated. Here, the effects of vacancy induced magnetic moments on the electrical properties of graphene are studied via magnetotransport measurements and spin-polarized density functional theory calculations. We show by quantum Hall measurements that a sharp resonant Vπ state is introduced in the midgap region of graphene with vacancies, resulting in the local magnetic moment. The coupling between the localized Vπ state and the itinerant carrier is tuned by varying the carrier concentration, temperature, magnetic field, and vacancy density, which results in a transition between hopping transport and the Kondo effect and a transition between giant negative magnetoresistance (MR) and positive MR. This modulated magnetotransport is valuable for graphene based spintronic devices.
Turbulence characteristics in sharp open-channel bends
Blanckaert, K.; De Vriend, H.J.
2005-01-01
In spite of its importance, little is known about the turbulence characteristics in open-channel bends. This paper reports on an experimental investigation of turbulence in one cross section of an open-channel bend. Typical flow features are a bicellular pattern of cross-stream circulation (secondar
On the Bending Problem for Large Scale Mapping
Esteban, I.; Booij, O.; Dijk, J.; Groen, F.
2010-01-01
During Simultaneous Localization And Mapping, geometrical constraints are established between map features. These constraints, introduced through measurements and motion prediction, produce a bending effect in the event of closing a large loop. In this paper we present a discussion of the bending pr
On the bending problem for large scale mapping
I. Esteban; O. Booij; J. Dijk; F. Groen
2009-01-01
During Simultaneous Localization And Mapping, geometrical constraints are established between map features. These constraints, introduced through measurements and motion prediction, produce a bending effect in the event of closing a large loop. In this paper we present a discussion of the bending pr
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.
36 CFR 7.41 - Big Bend National Park.
2010-07-01
... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Big Bend National Park. 7.41 Section 7.41 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.41 Big Bend National Park. (a) Fishing; closed...
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
System effects influencing the bending strength of timber beams
DEFF Research Database (Denmark)
Ditlevsen, Ove Dalager; Källsner, B.
1998-01-01
A stochastic model of hierarchical series system type for the bending strength of spruce beams isdefined from the anticipation that the bending failure takes place at a cross-section with a defect cluster formed by knots or grain irregularities. The parameters of the model are estimated from meas...
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.
Truncated Moment Analysis of Nucleon Structure Functions
Energy Technology Data Exchange (ETDEWEB)
A. Psaker; W. Melnitchouk; M. E. Christy; C. E. Keppel
2007-11-16
We employ a novel new approach using "truncated" moments, or integrals of structure functions over restricted regions of x, to study local quark-hadron duality, and the degree to which individual resonance regions are dominated by leading twists. Because truncated moments obey the same Q^2 evolution equations as the leading twist parton distributions, this approach makes possible for the first time a description of resonance region data and the phenomenon of quark-hadron duality directly from QCD.
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...
From Moments to Functions in Quantum Chromodynamics
Blümlein, J; Klein, S; Schneider, C
2009-01-01
Single-scale quantities, like the QCD anomalous dimensions and Wilson 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.
On the Neutron Electric Dipole Moment
Institute of Scientific and Technical Information of China (English)
Z. Bentalha; O. Lazrec
2004-01-01
@@ Within the Kobayashi-Maskawa mechanism of electroweak interaction and using the recent measured mass of the top quark, we estimate the neutron electric dipole moment (NEDM) via the diquark electroweak interaction.The resulting moment is about 10-30 e cm. The actual upper bound on the NEDM is 6.3 × 10-26 ecm and it can reach the value 5 × 10-28 ecm predicted by experiments in recent years.
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.
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.)
Ultrasensitive vector bending sensor based on multicore optical fiber.
Villatoro, Joel; Van Newkirk, Amy; Antonio-Lopez, Enrique; Zubia, Joseba; Schülzgen, Axel; Amezcua-Correa, Rodrigo
2016-02-15
In this Letter, we demonstrate a compellingly simple directional bending sensor based on multicore optical fibers (MCF). The device operates in reflection mode and consists of a short segment of a three-core MCF that is fusion spliced at the distal end of a standard single mode optical fiber. The asymmetry of our MCF along with the high sensitivity of the supermodes of the MCF make the small bending on the MCF induce drastic changes in the supermodes, their excitation, and, consequently, on the reflected spectrum. Our MCF bending sensor was found to be highly sensitive (4094 pm/deg) to small bending angles. Moreover, it is capable of distinguishing multiple bending orientations. PMID:26872200
Sorting of bending magnets for the SSRF booster
Institute of Scientific and Technical Information of China (English)
HOU Jie; LIU Gui-Min; LI Hao-Hu; ZHANG Man-Zhou
2008-01-01
The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.
Sorting of bending magnets for the SSRF booster
Hou, Jie; Liu, Gui-Min; Li, Hao-Hu; Zhang, Man-Zhou
2008-04-01
The Shanghai Synchrotron Radiation Facility (SSRF)booster ring, a full energy injector for the storage ring, is deigned to accelerate the electron beam energy from 150 MeV to 3.5 GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping. Closed orbit distortion (COD) caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting. Considering the affections of random errors in measurement, both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5 is given as the final installation sequence of the booster bending magnets in this paper. Supported by SSRF Project
Analysis and Simulation of Adiabatic Bend Transitions in Optical Fibers
Institute of Scientific and Technical Information of China (English)
YAO Lei; LOU Shu-Qin; JIAN Shui-Sheng
2009-01-01
A low-loss criterion for bend transitions in optical fibers is proposed. An optical fiber can be tightly bent with low loss to be adiabatic for the fundamental mode, provided that an approximate upper bound on the rate of change of bend curvature for a given bend curvature is satisfied. Two typical adiabatic bend transition paths, the optimum profile and linear profile, are analyzed and studied numerically. A realizable adiabatic transition with an Archimedean spiral profile is introduced for low bend loss in tightly bent optical fibers. Design of the transitions is based on modeling of the propagation and coupling characteristics of the core and cladding modes,which clearly illustrate the physical processes involved.
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.
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^...
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.
Schmidt, Hendrik; Heuer, Frank; Wilke, Hans-Joachim
2009-01-01
Dynamic stabilization devices have been introduced to clinics as an alternative to rigid fixation. The stiffness of these devices varies widely, whereas the optimal stiffness, achieving a predefined stabilization of the spine, is unknown. This study was focused on the determination of stiffness values for posterior stabilization devices achieving a flexible, semi-flexible or rigid connection between two vertebrae. An extensively validated finite element model of a lumbar spinal segment L4-5 with an implanted posterior fixation device was used in this study. The model was exposed to pure moments of 7.5 and 20Nm around the three principal anatomical directions, simulating flexion, extension, lateral bending and axial rotation. In parametrical studies, the influence of the axial and bending fixator stiffness on the spinal range of motion was investigated. In order to examine the validity of the computed results, an in-vitro study was carried out. In this, the influence of two posterior stabilization devices (DSS and rigidly internal fixator) on the segmental stabilization was investigated. The finite element (FE)-model predicted that each load direction caused a pairing of stiffness relations between axial and bending stiffness. In flexion and extension, however, the bending stiffness had a neglectable effect on the segmental stabilization, compared to the axial stiffness. In contrast, lateral bending and axial rotation were influenced by both stiffness parameters. Except in axial rotation, the model predictions were in a good agreement with the determined in-vitro data. In axial rotation, the FE-model predicted a stiffer segmental behavior than it was determined in the in-vitro study. It is usually expected that high stiffness values are required for a posterior stabilization device to stiffen a spinal segment. We found that already small stiffness values were sufficient to cause a stiffening. Using these data, it may possible to develop implants for certain clinical
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.
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.
2010-11-24
... decision-making process so interested and affected public may ] participate and contribute to the final... improve forest health and fuel conditions within the 25,700-acre West Bend planning area. The planning..., and on the west by the Bend Watershed Roadless Area. The planning area is entirely within public...
Four-dimensional transform fault processes: progressive evolution of step-overs and bends
Wakabayashi, John; Hengesh, James V.; Sawyer, Thomas L.
2004-11-01
Many bends or step-overs along strike-slip faults may evolve by propagation of the strike-slip fault on one side of the structure and progressive shut-off of the strike-slip fault on the other side. In such a process, new transverse structures form, and the bend or step-over region migrates with respect to materials that were once affected by it. This process is the progressive asymmetric development of a strike-slip duplex. Consequences of this type of step-over evolution include: (1) the amount of structural relief in the restraining step-over or bend region is less than expected; (2) pull-apart basin deposits are left outside of the active basin; and (3) local tectonic inversion occurs that is not linked to regional plate boundary kinematic changes. This type of evolution of step-overs and bends may be common along the dextral San Andreas fault system of California; we present evidence at different scales for the evolution of bends and step-overs along this fault system. Examples of pull-apart basin deposits related to migrating releasing (right) bends or step-overs are the Plio-Pleistocene Merced Formation (tens of km along strike), the Pleistocene Olema Creek Formation (several km along strike) along the San Andreas fault in the San Francisco Bay area, and an inverted colluvial graben exposed in a paleoseismic trench across the Miller Creek fault (meters to tens of meters along strike) in the eastern San Francisco Bay area. Examples of migrating restraining bends or step-overs include the transfer of slip from the Calaveras to Hayward fault, and the Greenville to the Concord fault (ten km or more along strike), the offshore San Gregorio fold and thrust belt (40 km along strike), and the progressive transfer of slip from the eastern faults of the San Andreas system to the migrating Mendocino triple junction (over 150 km along strike). Similar 4D evolution may characterize the evolution of other regions in the world, including the Dead Sea pull-apart, the Gulf
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.
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
Four-Dimensional Transform Fault Processes: Evolution of Step-Overs and Bends at Different Scales
Wakabayashi, J.; Hengesh, J. V.; Sawyer, T. L.
2002-12-01
Many bends or step-overs along strike-slip faults may evolve by propagation of the strike-slip fault on one side of the structure and progressive shut off of the strike-slip fault on the other side. In such a process, new transverse structures form, old ones become inactive, and the bend or step-over region migrates with respect to materials that were once affected by it. This process is the progressive asymmetric development of a strike-slip duplex. Consequences of this type of step-over evolution include the following: 1. the amount of vertical structural relief in restraining step-over or bend regions is less than expected (apatite fission track ages associated with these step-over regions predate the strike-slip faulting); 2. pull-apart basin deposits are left outside of the active basin and commonly subjected to contractional deformation and uplift; and 3. local basin inversion occurs that is not linked to regional plate motion changes. This type of evolution of step-overs and bends may be common along the dextral San Andreas fault system of California. Examples of pull-apart basin deposits related to migrating releasing () bends or step-overs are the Plio-Pleistocene Merced Formation (tens of km along strike), the Pleistocene Olema Creek Formation (several km along strike) along the San Andreas fault in the San Francisco Bay area, and an inverted colluvial graben exposed in a paleoseismic trench across the Miller Creek fault (meters to tens of meters along strike) in the eastern San Francisco Bay area. Examples of migrating restraining bends or step-overs include the transfer of slip from the Calaveras to Hayward fault in the Mission Peak area, and the Greenville to the Concord fault at Mount Diablo (10 km or more along strike), the offshore San Gregorio fold and thrust belt (40 km along strike), and the progressive transfer of slip from the eastern faults of the San Andreas system to the migrating Mendocino triple junction (over 150 km along strike). Another
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 ...
Seventeen Moments in Soviet History
Bhatia, Karan; Edwards, Zak; Layser, Matthew; Moore, Austin
2015-01-01
Items included: SovietHistory-Final (1).docx - Editable Word Document of Final Report. SovietHistory-Final (3).pdf - PDF version of final report. SovietHistory.pdf - Final Complete requirements report. SovietHistoryReport.pdf - PDF version of our report for easier viewing. SovietHistoryPresentation.pdf - PDF version of our PowerPoint presentation for our project. SovietHistoryPresentation.pptx - PowerPoint version of our project presentation. This describes results of t...
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.
Continuous time random walk: Galilei invariance and relation for the nth moment
Sau Fa, Kwok
2011-01-01
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.
Inhibition of the gravitropic bending response of flowering shoots by salicylic acid.
Friedman, Haya; Meir, Shimon; Halevy, Abraham H; Philosoph-Hadas, Sonia
2003-10-01
The upward gravitropic bending of cut snapdragon, lupinus and anemone flowering shoots was inhibited by salicylic acid (SA) applied at 0.5 mM and above. This effect was probably not due to acidification of the cytoplasm, since other weak acids did not inhibit bending of snapdragon shoots. In order to study its mode of inhibitory action, we have examined in cut snapdragon shoots the effect of SA on three processes of the gravity-signaling pathway, including: amyloplast sedimentation, formation of ethylene gradient across the stem, and differential growth response. The results show that 1 mM SA inhibited differential ethylene production rates across the horizontal stem and the gravity-induced growth, without significantly inhibiting vertical growth or amyloplast sedimentation following horizontal placement. However, 5 mM SA inhibited all three gravity-induced processes, as well as the growth of vertical shoots, while increasing flower wilting. It may, therefore, be concluded that SA inhibits bending of various cut flowering shoots in a concentration-dependent manner. Thus, at a low concentration SA exerts its effect in snapdragon shoots by inhibiting processes operating downstream to stimulus sensing exerted by amyloplast sedimentation. At a higher concentration SA inhibits bending probably by exerting general negative effects on various cellular processes.
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)
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
A Study of Neutron Star Structure in Strong Magnetic Fields that includes Anomalous Magnetic Moments
Institute of Scientific and Technical Information of China (English)
Guang-Jun Mao; Akira Iwamoto; Zhu-Xia Li
2003-01-01
We study the effect of strong magnetic fields on the structure of neutronstar. We find that if the interior field is on the same order as the surface fieldcurrently observed, then the influences of the field on the star's mass and radius arenegligible; if the field is as large as that estimated from the scalar virial theorem,then considerable effects will be induced. The maximum mass of the star will beincreased substantially while the central density is greatly reduced. The radius ofa magnetic star can be larger by about 10% ～ 20% than a nonmagnetic star of thesame mass.
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.
Energy Technology Data Exchange (ETDEWEB)
Zhang, G. P., E-mail: gpzhang@indstate.edu [Department of Physics, Indiana State University, Terre Haute, Indiana 47809 (United States); Si, M. S. [Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000 (China); George, Thomas F. [Office of the Chancellor and Center for Nanoscience, Departments of Chemistry and Biochemistry and Physics and Astronomy, University of Missouri-St. Louis, St. Louis, Missouri 63121 (United States)
2015-05-07
When a laser pulse excites a ferromagnet, its spin undergoes a dramatic change. The initial demagnetization process is very fast. Experimentally, it is found that the demagnetization time is related to the spin moment in the sample. In this study, we employ the first-principles method to directly simulate such a process. We use the fixed spin moment method to change the spin moment in ferromagnetic nickel, and then we employ the Liouville equation to couple the laser pulse to the system. We find that in general the dependence of demagnetization time on the spin moment is nonlinear: It decreases with the spin moment up to a point, after which an increase with the spin moment is observed, followed by a second decrease. To understand this, we employ an extended Heisenberg model, which includes both the exchange interaction and spin-orbit coupling. The model directly links the demagnetization rate to the spin moment itself and demonstrates analytically that the spin relaxes more slowly with a small spin moment. A future experimental test of our predictions is needed.
Zhang, G. P.; Si, M. S.; George, Thomas F.
2015-05-01
When a laser pulse excites a ferromagnet, its spin undergoes a dramatic change. The initial demagnetization process is very fast. Experimentally, it is found that the demagnetization time is related to the spin moment in the sample. In this study, we employ the first-principles method to directly simulate such a process. We use the fixed spin moment method to change the spin moment in ferromagnetic nickel, and then we employ the Liouville equation to couple the laser pulse to the system. We find that in general the dependence of demagnetization time on the spin moment is nonlinear: It decreases with the spin moment up to a point, after which an increase with the spin moment is observed, followed by a second decrease. To understand this, we employ an extended Heisenberg model, which includes both the exchange interaction and spin-orbit coupling. The model directly links the demagnetization rate to the spin moment itself and demonstrates analytically that the spin relaxes more slowly with a small spin moment. A future experimental test of our predictions is needed.
Homogeneous spaces, multi-moment maps and (2,3)-trivial algebras
DEFF Research Database (Denmark)
Madsen, T. B.; Swann, A.
2011-01-01
For geometries with a closed three-form we briefly overview the notion of multi-moment maps. We then give concrete examples of multi-moment maps for homogeneous hypercomplex and nearly Kahler manifolds. A special role in the theory is played by Lie algebras with second and third Betti numbers equal...... to zero. These we call (2,3)-trivial. We provide a number of examples of such algebras including a complete list in dimensions up to and including five....
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...
Buffers Affect the Bending Rigidity of Model Lipid Membranes
DEFF Research Database (Denmark)
Bouvrais, H.; Duelund, L.; Ipsen, J. H.
2014-01-01
In biophysical and biochemical studies of lipid bilayers the influence of the used buffer is often ignored or assumed to be negligible on membrane structure, elasticity, or physical properties. However, we here present experimental evidence, through bending rigidity measurements performed on giant...... vesicles, of a more complex behavior, where the buffering molecules may considerably affect the bending rigidity of phosphatidylcholine bilayers. Furthermore, a synergistic effect on the bending modulus is observed in the presence of both salt and buffer molecules, which serves as a warning...... to experimentalists in the data interpretation of their studies, since typical lipid bilayer studies contain buffer and ion molecules....
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)
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...
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
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.
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.
MCDHF calculations of the electric dipole moment of radium induced by the nuclear Schiff moment
Bieron, Jacek; Gaidamauskas, Erikas; Fritzsche, Sephan; Indelicato, Paul; Jönsson, Per
2009-01-01
The multiconfiguration Dirac-Hartree-Fock theory (MCDHF) has been employed to calculate the electric dipole moment of the 7s6d 3D2 state of radium induced by the nuclear Schiff moment. The results are dominated by valence and core-valence electron correlation effects. We show that the correlation effects can be evaluated in a converged series of multiconfiguration expansions.
Measurement of the electric dipole moment and magnetic moment anomaly of the muon
Onderwater, CJG
2005-01-01
The experimental precision of the anomalous magnetic moment of the muon has been improved to 0.5 part-per-million by the Brookhaven E821 experiment, similar to the theoretical uncertainty. In the same experiment, a new limit on the electric dipole moment of 2.8 x 10(-19) e-cm (95% CL) was set. The e
Skew t distribution and its moments
Institute of Scientific and Technical Information of China (English)
Saralees NADARAJAH; Arjun K.GUPTA
2006-01-01
A random variable X is said to have the skew- t distribution if its pdf is f (x) = 2g (x) G (λx), where g (·) and G(·), respectively, denote the pdf and the cdf of the Student's t distribution with degrees of freedom ν. The moments of this distribution appear not to have been studied in detail. In this paper, we derive general expressions for the nth moment of X by considering the cases ν odd and ν even separately. These expressions turn out to involve sums of the Gauss hypergeometric function. We also provide closed form expressions for the moments of X for the particular cases ν = 2, …, 10.
Moment distributions of phase-type
DEFF Research Database (Denmark)
Bladt, Mogens; Nielsen, Bo Friis
2012-01-01
with phase-type distributions. For the first order distribution we present an explicit formula for the related Lorenz curve and Gini index. Moment distributions of orders one, two and three have been extensively used in areas such as economy, physics, demography and civil engineering.......Both matrix-exponential and phase-type distributions have a number of important closure properties. Among those are the distributions of the age and residual life-time of a stationary renewal process with inter-arrivals of either type. In this talk we show that the spread, which is the sum...... of the age an residual life-time, is also phase-type distributed. Moreover, we give some explicit representations. The spread is known to have a first order moment distribution. If X is a positive random variable and ?i is its i'th moment, then the function fi(x) = xif(x)/?i is a density function...
The inverse moment problem for convex polytopes
Gravin, Nick; Pasechnik, Dmitrii; Robins, Sinai
2011-01-01
The goal of this paper is to present a general and novel approach for the reconstruction of any convex d-dimensional polytope P, from knowledge of its moments. In particular, we show that the vertices of an N-vertex polytope in R^d can be reconstructed from the knowledge of O(DN) axial moments (w.r.t. to an unknown polynomial measure od degree D) in d+1 distinct generic directions. Our approach is based on the collection of moment formulas due to Brion, Lawrence, Khovanskii-Pukhikov, and Barvinok that arise in the discrete geometry of polytopes, and what variously known as Prony's method, or Vandermonde factorization of finite rank Hankel matrices.
Real object recognition using moment invariants
Indian Academy of Sciences (India)
Muharrem Mercimek; Kayhan Gulez; Tarik Veli Mumcu
2005-12-01
Moments and functions of moments have been extensively employed as invariant global features of images in pattern recognition. In this study, a flexible recognition system that can compute the good features for high classiﬁcation of 3-D real objects is investigated. For object recognition, regardless of orientation, size and position, feature vectors are computed with the help of nonlinear moment invariant functions. Representations of objects using two-dimensional images that are taken from different angles of view are the main features leading us to our objective. After efﬁcient feature extraction, the main focus of this study, the recognition performance of classiﬁers in conjunction with moment–based feature sets, is introduced.
Magnetic moment nonconservation in magnetohydrodynamic turbulence models.
Dalena, S; Greco, A; Rappazzo, A F; Mace, R L; Matthaeus, W H
2012-07-01
The fundamental assumptions of the adiabatic theory do not apply in the presence of sharp field gradients or in the presence of well-developed magnetohydrodynamic turbulence. For this reason, in such conditions the magnetic moment μ is no longer expected to be constant. This can influence particle acceleration and have considerable implications in many astrophysical problems. Starting with the resonant interaction between ions and a single parallel propagating electromagnetic wave, we derive expressions for the magnetic moment trapping width Δμ (defined as the half peak-to-peak difference in the particle magnetic moments) and the bounce frequency ω(b). We perform test-particle simulations to investigate magnetic moment behavior when resonance overlapping occurs and during the interaction of a ring-beam particle distribution with a broadband slab spectrum. We find that the changes of magnetic moment and changes of pitch angle are related when the level of magnetic fluctuations is low, δB/B(0) = (10(-3),10(-2)), where B(0) is the constant and uniform background magnetic field. Stochasticity arises for intermediate fluctuation values and its effect on pitch angle is the isotropization of the distribution function f(α). This is a transient regime during which magnetic moment distribution f(μ) exhibits a characteristic one-sided long tail and starts to be influenced by the onset of spatial parallel diffusion, i.e., the variance grows linearly in time as in normal diffusion. With strong fluctuations f(α) becomes completely isotropic, spatial diffusion sets in, and the f(μ) behavior is closely related to the sampling of the varying magnetic field associated with that spatial diffusion.
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.
Nucleon Magnetic Moments and Electric Polarizabilities
Energy Technology Data Exchange (ETDEWEB)
W Detmold, B C Tiburzi, A Walker-Loud
2010-06-01
Electromagnetic properties of the nucleon are explored with lattice QCD using a novel technique. Focusing on background electric fields, we show how the electric polarizability can be extracted from nucleon correlation functions. A crucial step concerns addressing contributions from the magnetic moment, which affects the relativistic propagation of nucleons in electric fields. By properly handing these contributions, we can determine both magnetic moments and electric po larizabilities. Lattice results from anisotropic clover lattices are presented. Our method is not limited to the neutron; we show results for the proton as well.
Second moment of the pion's distribution amplitude
International Nuclear Information System (INIS)
We present preliminary results from the QCDSF/UKQCD collaborations for the second moment of the pion's distribution amplitude with two flavours of dynamical fermions. We use nonperturbatively determined renormalisation coefficients to convert our results to the MS scheme at 5 GeV2. Employing a linear chiral extrapolation from our large pion masses > 550 MeV, we find left angle ξ2 right angle = 0.281(28), leading to a value of α2 = 0.236(82) for the second Gegenbauer moment. (orig.)
Second moment of the pion's distribution amplitude
International Nuclear Information System (INIS)
We present preliminary results from the QCDSF/UKQCD collaborations for the second moment of the pion's distribution amplitude with two flavours of dynamical fermions. We use nonperturbatively determined renormalisation coefficients to convert our results to the MS-bar scheme at 5GeV2. Employing a linear chiral extrapolation from our large pion masses >550MeV, we find 2>=0.281(28), leading to a value of a2=0.236(82) for the second Gegenbauer moment
Moment searching algorithm for bioluminescence tomography
Institute of Scientific and Technical Information of China (English)
Ludong Jin; Yan Wu; Jie Tian; Heyu Huang; Xiaochao Qu
2009-01-01
To avoid the ill-posedness in the inverse problem of bioluminescence tomography, a moment searching algorithm fusing the finite element method (FEM) with the moment concept in theoretical mechanics is developed. In the algorithm, the source's information is mapped to the surface photon flux density by FEM, and the source's position is modified with the feedback through the algorithm of barycenter searching, which makes full use of the position information of the photon flux density on surface. The position is modified in every iterative step and will finally converge to the real source's value theoretically.
Dipole moments of the τ-neutrino
International Nuclear Information System (INIS)
Bounds on the anomalous magnetic moment and the electric dipole moment of the τ -neutrino are calculated through the reaction e+e- → ν ν-bar γ at the Z1-pole, and in the framework of a left-right symmetric model. The results are based on the recent data reported by the L3 Collaboration at CERN LEP. We find that the bounds are almost independent of the mixing angle φ of the model in the allowed experimental range for this parameter
Moment in Peking and Chinese Traditional Culture
Institute of Scientific and Technical Information of China (English)
杨晶金
2014-01-01
Lin Yutang’s Moment in Peking was a huge success, because he showed the long history of Chinese traditional culture in the book. The era background, character set and the plot of Moment in Peking reflects the significance of Chinese culture in many aspects. The great English masterpiece is a Chinese culture carrier which painted a grand social and historical picture, created a series of vivid images, especially images of traditional Chinese women character. The philosophy of novel is going through the history of space and time tunnel and becoming the main clue of many events in the book.
Distortional Buckling Analysis of Steel-Concrete Composite Girders in Negative Moment Area
Directory of Open Access Journals (Sweden)
Zhou Wangbao
2014-01-01
Full Text Available Distortional buckling is one of the most important buckling modes of the steel-concrete composite girder under negative moment. In this study, the equivalent lateral and torsional restraints of the bottom flange of a steel-concrete composite girder under negative moments due to variable axial forces are thoroughly investigated. The results show that there is a coupling effect between the applied forces and the lateral and torsional restraint of the bottom flange. Based on the calculation formula of lateral and torsional restraints, the critical buckling stress of I-steel-concrete composite girders and steel-concrete composite box girders under variable axial force is obtained. The critical bending moment of the steel-concrete composite girders can be further calculated. Compared to the traditional calculation methods of elastic foundation beam, the paper introduces an improved method, which considers coupling effect of the external loads and the foundation spring constraints of the bottom flange. Fifteen examples of the steel-concrete composite girders in different conditions are calculated. The calculation results show a good match between the hand calculation and the ANSYS finite element method, which validated that the analytic calculation method proposed in this paper is practical.
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.
Computational Strategies for the Architectural Design of Bending Active Structures
DEFF Research Database (Denmark)
Tamke, Martin; Nicholas, Paul
2013-01-01
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 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...
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...
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...
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...
Tang, Jiqiang; Xiang, Biao; Zhang, Yongbin
2014-07-01
For a magnetically suspended control moment gyroscope, stiffness and damping of magnetic bearing will influence modal frequency of a rotor. In this paper the relationship between modal frequency and stiffness and damping has been investigated. The mathematic calculation model of axial passive magnetic bearing (PMB) stiffness is developed. And PID control based on internal model control is introduced into control of radial active magnetic bearing (AMB), considering the radial coupling of axial PMB, a mathematic calculation model of stiffness and damping of radial AMB is established. According to modal analysis, the relationship between modal frequency and modal shapes is achieved. Radial vibration frequency is mainly influenced by stiffness of radial AMB; however, when stiffness increases, radial vibration will disappear and a high frequency bending modal will appear. Stiffness of axial PMB mainly affects the axial vibration mode, which will turn into high-order bending modal. Axial PMB causes bigger influence on torsion modal of the rotor.
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
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.
Accounting for Fiber Bending Effects in Homogenization of Long Fiber Reinforced Composites
DEFF Research Database (Denmark)
Poulios, Konstantinos; Niordson, Christian Frithiof
2015-01-01
of the material micro-structure including individual fibers, homogenized models are computationally more efficient and hence more suitable for modeling of larger and complex structure. Nevertheless, the formulation of homogenized models is more complicated, especially if the bending stiffness of the reinforcing...... constitutive laws for the fiber and the matrix materials, respectively expressed in the frameworks of hyper-elasticity and hyper-elasto-plasticity. The presented numerical results include comparisons between the homogenized model and an explicit discretization of the composite microstructure. Both models...... are in good agreement. In cases where the fiber bending stiffness is significant,the homogenized finite-element model exhibits size-scale dependent material behavior, as predicted by the model with explicitly discretized individual fibers....
A limit theorem for moments in space of the increments of Brownian local time
Campese, Simon
2015-01-01
We proof a limit theorem for moments in space of the increments of Brownian local time. As special cases for the second and third moments, previous results by Chen et al. (Ann. Prob. 38, 2010, no. 1) and Rosen (Stoch. Dyn. 11, 2011, no. 1), which were later reproven by Hu and Nualart (Electron. Commun. Probab. 14, 2009; Electron. Commun. Probab. 15, 2010) and Rosen (S\\'eminaire de Probabilit\\'es XLIII, Springer, 2011) are included. Furthermore, a conjecture of Rosen for the fourth moment is s...
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...
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.
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...
Real Moments of the Restrictive Factor
Indian Academy of Sciences (India)
Andrew Ledoan; Alexandru Zaharescu
2009-09-01
Let be a real number such that 0 < < 1. We establish asymptotic formulas for the weighted real moments $\\sum_{n≤ x}R^(n)(1-n/x)$, where $R(n)=\\prod^k_{v=1}p^{ v-1}_v$ is the Atanassov strong restrictive factor function and $n=\\prod^k_{v=1}p^{ v}_v$ is the prime factorization of .
Moments in Collaboration: Experiments in Concept Work
DEFF Research Database (Denmark)
Korsby, Trine Mygind; Stavrianakis, Anthony
2016-01-01
-discursive entities, created through and emerging as objects and practices of inquiry. The article focuses on the centrality of specific moments of conceptual creation through collaboration, understood as the temporal, material and affective qualities of thinking together. Keywords: Collaboration, form, ethics...
Using Aha! Moments to Understand Leadership Theory
Moore, Lori L.; Lewis, Lauren J.
2012-01-01
As Huber (2002) noted, striving to understand how leadership is taught and learned is both a challenge and an opportunity facing leadership educators. This article describes the "Leadership Aha! Moment" assignment used in a leadership theory course to help students recognize the intersection of leadership theories and their daily lives while…
The Approach of Moments for Polynomial Equations
Laurent, M.; Rostalski, P.
2010-01-01
In this article we present the moment based approach for computing all real solutions of a given system of polynomial equations. This approach builds upon a lifting method for constructing semidefinite relaxations of several nonconvex optimization problems, using sums of squares of polynomials and t
A Note on Moments of Dividends
Institute of Scientific and Technical Information of China (English)
Hansj(o)rg Albrecher; Hans U. Gerber
2011-01-01
We reconsider a formula for arbitrary moments of expected discounted dividend payments in a spectrally negative Lévy risk model that was obtained in Renaud and Zhou (2007, [4]) and in Kyprianou and Palmowski (2007, [3]) and extend the result to stationary Markov processes that are skip-free upwards.
The isotopic dipole moment of HDO
Energy Technology Data Exchange (ETDEWEB)
Assafrao, Denise; Mohallem, Jose R [Laboratorio de Atomos e Moleculas Especiais, Departamento de Fisica, ICEx, Universidade Federal de Minas Gerais, CP 702, 30123-970, Belo Horizonte, MG (Brazil)
2007-03-14
An adiabatic variational approximation is used to study the monodeuterated water molecule, HDO, accounting for the isotopic effect. The isotopic dipole moment, pointing from D to H, is then calculated for the first time, yielding (1.5 {+-} 0.1) x 10{sup -3} Debye, being helpful in the interpretation of experiments. (fast track communication)
Critical moments in police-citizen reconciliation
Stronks, Sara; Adang, Otto M. J.
2015-01-01
Purpose - The purpose of this paper is to analyze the interaction of police and citizen representatives during critical moments in reconciliation processes through a relational model. Design/methodology/approach - Based on 26 in-depth interviews with key actors in three different cases of media-sali
Magnetic moment of iron in metallic environments
International Nuclear Information System (INIS)
Rare-earth iron nitrides are emerging as an important class of magnetic materials. In certain rare-earth iron compounds, the insertion of small atoms such as nitrogen and boron has resulted in significant changes in the magnetic properties in the form of higher Curie temperatures, enhanced magnetic moments, and stronger anisotropies. In an attempt to understand some of the above, we have focused on two nitride phases of Fe, namely Fe4N (cubic) and Fe16N2 (tetragonal). For the Fe16N2 phase, the average Fe moment reported by different experimental groups varies over a wide range of values, from 2.3μB to 3.5μB. We will discuss some of the recent experiments and examine some related theoretical questions with regard to Fe having such an unusually large moment in a metallic environment. Employing a Hubbard-Stoner-like model in addition to local-density results, it is shown that an unusually large on-site Coulomb repulsion is necessary if one is to obtain a moment as large as 3.5μB. (c) 2000 The American Physical Society
The Doubling Moment: Resurrecting Edgar Allan Poe
Minnick, J. Bradley; Mergil, Fernando
2008-01-01
This article expands upon Jeffrey Wilhelm's and Brian Edmiston's (1998) concept of a doubling of viewpoints by encouraging middle level students to use dramatization to take on multiple perspectives, to pose interpretive questions, and to enhance critical inquiry from inside and outside of texts. The doubling moment is both the activation of…
Anomalous magnetic moment and Compton wavelength
Heyrovska, Raji
2004-01-01
The relativistic and quantum theoretical explanations of the magnetic moment anomaly of the electron (or proton) show that it is a complicated function of the fine structure constant. In this work, a simple non-relativistic approach shows that the translational motion of the particle during its spin is responsible for the observed effects.
Transition radiation of the neutrino magnetic moment
Sakuda, M.; Kurihara, Y
1994-01-01
If the neutrino has a finite mass and a magnetic moment it would produce transition radiation when crossing the interface between two media. We found that the probability of transition radiation is larger by an order of magnitude using the quantum theory than that recently reported by one of us using classical electrodynamics, and that the energy spectrum of the radiation is nearly uniform.
SEARCH FOR A NEUTRON ELECTRIC DIPOLE MOMENT
Morse, J
1984-01-01
To search for evidence of a breakdown of symmetry under the time reversal transformation, a magnetic resonance measurement is made to detect an electric dipole moment (EDM) of ultracold neutrons stored for periods ≈60s in the presence of a strong electric field. The measured neutron EDM is (0.3 ± 4.8) x 10-25 ecm.
Pedagogical Moments: Affective Sexual Literacies in Film
Clarke, Kyra
2013-01-01
This paper considers three pedagogical moments in the film "Tomorrow, When the War Began" (2010), contemplating the way in which they open a space for conversations about feelings, sexuality and gender. "Tomorrow, When the War Began" follows the plight of 17-year-old Ellie who returns to her rural town from a camping trip with…
Applications of circularly polarized photons at the ALS with a bend magnet source
Energy Technology Data Exchange (ETDEWEB)
1992-02-01
The purpose of this workshop is to focus attention on, and to stimulate the scientific exploitation of, the natural polarization properties of bend-magnet synchrotron radiation at the ALS -- for research in biology, materials science, physics, and chemistry. The topics include: The Advanced Light Source; Magnetic Circular Dichroism and Differential Scattering on Biomolecules; Tests of Fundamental Symmetries; High {Tc} Superconductivity; Photoemission from Magnetic and Non-magnetic Solids; Studies of Highly Correlated Systems; and Instrumentation for Photon Transport and Polarization Measurements.
Methods and apparatus for twist bend coupled (TCB) wind turbine blades
Moroz, Emilian Mieczyslaw; LeMieux, David Lawrence; Pierce, Kirk Gee
2006-10-10
A method for controlling a wind turbine having twist bend coupled rotor blades on a rotor mechanically coupled to a generator includes determining a speed of a rotor blade tip of the wind turbine, measuring a current twist distribution and current blade loading, and adjusting a torque of a generator to change the speed of the rotor blade tip to thereby increase an energy capture power coefficient of the wind turbine.
Applications of circularly polarized photons at the ALS with a bend magnet source
International Nuclear Information System (INIS)
The purpose of this workshop is to focus attention on, and to stimulate the scientific exploitation of, the natural polarization properties of bend-magnet synchrotron radiation at the ALS -- for research in biology, materials science, physics, and chemistry. The topics include: The Advanced Light Source; Magnetic Circular Dichroism and Differential Scattering on Biomolecules; Tests of Fundamental Symmetries; High Tc Superconductivity; Photoemission from Magnetic and Non-magnetic Solids; Studies of Highly Correlated Systems; and Instrumentation for Photon Transport and Polarization Measurements
Exploration of Learning Strategies Associated With Aha Learning Moments.
Pilcher, Jobeth W
2016-01-01
Educators recognize aha moments as powerful aspects of learning. Yet limited research has been performed regarding how to promote these learning moments. This article describes an exploratory study of aha learning moments as experienced and described by participants. Findings showed use of visuals, scenarios, storytelling, Socratic questions, and expert explanation led to aha learning moments. The findings provide guidance regarding the types of learning strategies that can be used to promote aha moments. PMID:26985751
Extracting the Omega- electric quadrupole moment from lattice QCD data
Energy Technology Data Exchange (ETDEWEB)
G. Ramalho, M.T. Pena
2011-03-01
The Omega- has an extremely long lifetime, and is the most stable of the baryons with spin 3/2. Therefore the Omega- magnetic moment is very accurately known. Nevertheless, its electric quadrupole moment was never measured, although estimates exist in different formalisms. In principle, lattice QCD simulations provide at present the most appropriate way to estimate the Omega- form factors, as function of the square of the transferred four-momentum, Q2, since it describes baryon systems at the physical mass for the strange quark. However, lattice QCD form factors, and in particular GE2, are determined at finite Q2 only, and the extraction of the electric quadrupole moment, Q_Omega= GE2(0) e/(2 M_Omega), involves an extrapolation of the numerical lattice results. In this work we reproduce the lattice QCD data with a covariant spectator quark model for Omega- which includes a mixture of S and two D states for the relative quark-diquark motion. Once the model is calibrated, it is used to determine Q_Omega. Our prediction is Q_Omega= (0.96 +/- 0.02)*10^(-2) efm2 [GE2(0)=0.680 +/- 0.012].
Moment tensors of a dislocation in a porous medium
Wang, Zhi; Hu, Hengshan
2016-06-01
A dislocation can be represented by a moment tensor for calculating seismic waves. However, the moment tensor expression was derived in an elastic medium and cannot completely describe a dislocation in a porous medium. In this paper, effective moment tensors of a dislocation in a porous medium are derived. It is found that the dislocation is equivalent to two independent moment tensors, i.e., the bulk moment tensor acting on the bulk of the porous medium and the isotropic fluid moment tensor acting on the pore fluid. Both of them are caused by the solid dislocation as well as the fluid-solid relative motion corresponding to fluid injection towards the surrounding rocks (or fluid outflow) through the fault plane. For a shear dislocation, the fluid moment tensor is zero, and the dislocation is equivalent to a double couple acting on the bulk; for an opening dislocation or fluid injection, the two moment tensors are needed to describe the source. The fluid moment tensor only affects the radiated compressional waves. By calculating the ratio of the radiation fields generated by unit fluid moment tensor and bulk moment tensor, it is found that the fast compressional wave radiated by the bulk moment tensor is much stronger than that radiated by the fluid moment tensor, while the slow compressional wave radiated by the fluid moment tensor is several times stronger than that radiated by the bulk moment tensor.
The effect of skin passing on the material behavior of metal strip in pure bending and tension
Weiss, Matthias; Ryan, Will; Rolfe, Bernard; Yang, Chunhui
2010-06-01
The metal strip used in roll forming has often been preprocessed by (tension or roller) leveling or by skin-pass rolling, and as a consequence, may contain residual stresses. These stresses are not well observed by the tensile test, but could have a significant effect on the bending and springback behavior. With the advent of improved process design techniques for roll forming, including advanced finite element techniques, the need for precise material property data has become important. The major deformation mode of roll forming is that of bending combined with unloading and reverse bending, and hence property data derived from bend tests could be more relevant than that from tensile testing. This work presents a numerical study on the effect of skin passing on the material behavior of stainless steel strip in pure bending and tension. A two dimensional (2-D) numerical model was developed using Abaqus Explicit to analyze the affect of skin passing on the residual stress profile across a section for various working conditions. The deformed meshes and their final stress fields were then imported as pre-defined fields into Abaqus Standard, and the post-skin passing material behavior in pure bending was determined. The results show that a residual stress profile is introduced into the steel strip during skin passing, and that its shape and stress level depend on the overall thickness reduction as well as the number of rolling passes used in the skin passing process. The material behavior in bending and the amount of springback changed significantly depending on the skin pass condition.
Magnetic moment and electric dipole moment of the τ-lepton
International Nuclear Information System (INIS)
Limits on the anomalous magnetic moment and the electric dipole moment of the τ lepton are calculated through the reaction e+e- → τ+τ- γ at the Z1-pole and in the framework of a left-right symmetric model. The results are based on the recent data reported by the L3 Collaboration at CERN LEP. Due to the stringent limit of the model mixing angle φ, the effect of this angle on the dipole moments is quite small
Energy Technology Data Exchange (ETDEWEB)
McGraw R.
2012-03-01
Moment methods are finding increasing usage for simulations of particle population balance in box models and in more complex flows including two-phase flows. These highly efficient methods have nevertheless had little impact to date for multi-moment representation of aerosols and clouds in atmospheric models. There are evidently two reasons for this: First, atmospheric models, especially if the goal is to simulate climate, tend to be extremely complex and take many man-years to develop. Thus there is considerable inertia to the implementation of novel approaches. Second, and more fundamental, the nonlinear transport algorithms designed to reduce numerical diffusion during advection of various species (tracers) from cell to cell, in the typically coarse grid arrays of these models, can and occasionally do fail to preserve correlations between the moments. Other correlated tracers such as isotopic abundances, composition of aerosol mixtures, hydrometeor phase, etc., are subject to this same fate. In the case of moments, this loss of correlation can and occasionally does give rise to unphysical moment sets. When this happens the simulation can come to a halt. Following a brief description and review of moment methods, the goal of this paper is to present two new approaches that both test moment sequences for validity and correct them when they fail. The new approaches work on individual grid cells without requiring stored information from previous time-steps or neighboring cells.
Directory of Open Access Journals (Sweden)
Andrea Bulletti
2015-01-01
Full Text Available Interdigital transducers fabricated with piezopolymer film have been realized to excite ultrasonic Lamb waves in a composite laminate subjected to pure bending stresses. Lamb waves were generated and detected in a cross-ply [0°/90°] 4 mm thick carbon-fiber composite, by using two interdigital transducers in pitch-catch configuration. We demonstrate that the choice of the piezopolymer transducer technology is suitable for this type of investigation and the advantages of the proposed transducer assembly and bonding are described. A full set-up is described to determine the relationship between the time of flight of the recorded signals and the applied bending moment. Interdigital transducers were designed according to simulations of the dispersion curves, in order to operate at a central frequency of 450 kHz. This frequency corresponds to a central wavelength of 16 mm and to a group velocity of about 6000 m/s for the first symmetric guided wave mode. The variations in the time of flight of ultrasonic recorded signals were measured as a function of the variations in the bending moment. The static and dynamic load tests were in good agreement with strain gage measurements performed in the micro deformation range (0–1400 µm/m.
Thomas-BMT equation generalized to electric dipole moments and field gradients
Metodiev, Eric M.
2015-01-01
An expression is presented for the relativistic equations of motion, including field gradients, of a particle and its spin with electric and magnetic dipole moments aligned along the spin axis. An electromagnetic duality transformation is used to generalize a Thomas-BMT equation with gradient terms. Corrections to particle dynamics in storage rings for precision $(g-2)$ and electric dipole moment measurements are calculated, and applications to precision particle tracking programs are conside...
Finite temperature theory of the scissors mode in a Bose gas using the moment method
Nikuni, T.
2001-01-01
We use a generalized Gross-Pitaevskii equation for the condensate and a semi-classical kinetic equation for the noncondensate atoms to discuss the scissors mode in a trapped Bose-condensed gas at finite temperatures. Both equations include the effect of $C_{12}$ collisions between the condensate and noncondensate atoms. We solve the coupled moment equations describing oscillations of the quadrupole moments of the condensate and noncondensate components to find the collective mode frequencies ...
Study of thermodynamic properties of AuCu superlattice by the statistical moment method
International Nuclear Information System (INIS)
We have investigated the thermodynamic quantities of AuCu superlattice using the statistical moment method in the statistical physics. The free energy, thermal lattice expansion coefficients, mean-square atomic displacements, and specific heats at the constant volume and those at the constant pressure, Cv and Cp, are derived in closed analytic forms in terms of the power moments of the atomic displacements. The present analytic formulas including the anharmonic effects of the lattice vibration give the predicted values of these quantities.
Modeling and bonding-free fabrication of flexible fluidic microactuators with a bending motion
Gorissen, Benjamin; Vincentie, Wannes; Al-Bender, Farid; Reynaerts, Dominiek; De Volder, Michaël
2013-04-01
Flexible fluidic actuators recently attracted the interest of the microsystem community, especially for soft robotic applications including minimally invasive surgery. These actuators, based on a well-known actuator design where a void is surrounded by an asymmetric elastic structure, can achieve large bending strokes when pressurized. Miniaturized versions of these actuators typically fail due to poor bonding of constituting components, and further, there is little theoretical understanding of these devices. This paper presents a new actuator design which does not require any bonding and provides new insights into the modeling of these actuators. The newly developed production process of the actuators is based on out-of-plane high aspect ratio micromolding, which enables high-throughput bonding-free fabrication. Furthermore, a mathematical model based on Euler-Bernoulli's beam equation with a deformable cross section is developed that shows good agreement with validation experiments on prototypes. These theoretical insights greatly facilitate the design and optimization of flexible bending actuators.
Directory of Open Access Journals (Sweden)
K. Kamardin
2015-09-01
Full Text Available Textile diamond dipole and Artificial Magnetic Conductor (AMC have been proposed and tested under wearable and body centric measurements. The proposed antenna and AMC sheet are entirely made of textiles for both the substrate and conducting parts, thus making it suitable for wearable communications. Directive radiation patterns with high gain are obtained with the proposed AMC sheet, hence minimizing the radiation towards the human body. In this study, wearable and body centric measurements are investigated which include bending, wetness and Specific Absorption Rate (SAR. Bending is found not to give significant effect to the antenna and AMC performance, as opposed to wetness that yields severe performance distortion. However, the original performance is retrieved once the antenna and AMC dried. Moreover, notable SAR reduction is achieved with the introduction of the AMC sheet, which is appropriate to reduce the radiation that penetrates into human flesh.
Light bending in the galactic halo by Rindler-Ishak method
Bhattacharya, Amrita; Isaev, Ruslan; Scalia, Massimo; Cattani, Carlo; Nandi, Kamal K.
2010-09-01
After the work of Rindler and Ishak, it is now well established that the bending of light is influenced by the cosmological constant Λ appearing in the Schwarzschild-de Sitter spacetime. We show that their method, when applied to the exact Mannheim-Kazanas-de Sitter solution of the Weyl conformal gravity, nicely yields the expected answer together with several other physically interesting new terms. Apart from Λ, the solution is parametrized by a conformal parameter γ, which is known to play a dominant role in the galactic halo gravity. The application of the method yields exactly the same γ- correction to Schwarzschild bending as obtained by standard methods. Different cases are analyzed, which include some corrections to the special cases considered in the original paper by Rindler and Ishak.