Huang, Yonghui; Yang, Zhicheng; Liu, Airong; Fu, Jiyang
2018-05-28
The buckling behavior of functionally graded graphene platelet-reinforced composite (FG-GPLRC) shallow arches with elastic rotational constraints under uniform radial load is investigated in this paper. The nonlinear equilibrium equation of the FG-GPLRC shallow arch with elastic rotational constraints under uniform radial load is established using the Halpin-Tsai micromechanics model and the principle of virtual work, from which the critical buckling load of FG-GPLRC shallow arches with elastic rotational constraints can be obtained. This paper gives special attention to the effect of the GPL distribution pattern, weight fraction, geometric parameters, and the constraint stiffness on the buckling load. The numerical results show that all of the FG-GPLRC shallow arches with elastic rotational constraints have a higher buckling load-carrying capacity compared to the pure epoxy arch, and arches of the distribution pattern X have the highest buckling load among four distribution patterns. When the GPL weight fraction is constant, the thinner and larger GPL can provide the better reinforcing effect to the FG-GPLRC shallow arch. However, when the value of the aspect ratio is greater than 4, the flakiness ratio is greater than 103, and the effect of GPL's dimensions on the buckling load of the FG-GPLRC shallow arch is less significant. In addition, the buckling model of FG-GPLRC shallow arch with elastic rotational constraints is changed as the GPL distribution patterns or the constraint stiffness changes. It is expected that the method and the results that are presented in this paper will be useful as a reference for the stability design of this type of arch in the future.
Comparison of Deterministic and Probabilistic Radial Distribution Systems Load Flow
Gupta, Atma Ram; Kumar, Ashwani
2017-12-01
Distribution system network today is facing the challenge of meeting increased load demands from the industrial, commercial and residential sectors. The pattern of load is highly dependent on consumer behavior and temporal factors such as season of the year, day of the week or time of the day. For deterministic radial distribution load flow studies load is taken as constant. But, load varies continually with a high degree of uncertainty. So, there is a need to model probable realistic load. Monte-Carlo Simulation is used to model the probable realistic load by generating random values of active and reactive power load from the mean and standard deviation of the load and for solving a Deterministic Radial Load Flow with these values. The probabilistic solution is reconstructed from deterministic data obtained for each simulation. The main contribution of the work is: Finding impact of probable realistic ZIP load modeling on balanced radial distribution load flow. Finding impact of probable realistic ZIP load modeling on unbalanced radial distribution load flow. Compare the voltage profile and losses with probable realistic ZIP load modeling for balanced and unbalanced radial distribution load flow.
International Nuclear Information System (INIS)
Kim, Haksung; Ho Pyeon, Cheol; Lim, Jae-Yong; Misawa, Tsuyoshi
2012-01-01
The effects of silicon cross section and neutron spectrum on the radial uniformity of a Si-ingot are examined experimentally with various neutron spectrum conditions. For the cross section effect, the numerical results using silicon single crystal cross section reveal good agreements with experiments within relative difference of 6%, whereas the discrepancy is approximately 20% in free-gas cross section. For the neutron spectrum effect, the radial uniformity in hard neutron spectrum is found to be more flattening than that in soft spectrum. - Highlights: ► The effects of silicon cross section and neutron spectrum on the radial uniformity in NTD were experimentally investigated. ► The numerical results using silicon single crystal cross section reveal good agreements. ► The radial uniformity in hard neutron spectrum was more flat than that in soft spectrum. ► The silicon single crystal cross section and hard neutron spectrum are recommended for numerical analyses and radial uniformity flattening in NTD, respectively.
Directory of Open Access Journals (Sweden)
Christos F. Markides
2017-04-01
Full Text Available A recently introduced solution for the stress- and displacement-fields, developed in a multi-layered circular ring, composed of a finite number of linearly elastic concentric layers, subjected to a parabolic distribution of ra-dial stresses, is here extended to encompass a more general loading scheme, closer to actual conditions. The loading scheme includes, besides the para¬-bolic radial stresses, a combination of uniform pressures acting along the outer- and inner- most boundaries of the layered ring. The analytic solution of the problem is achieved by adopting Savin’s pioneering approach for an infinite plate with a hole strengthened by rings. Taking advantage of the results provided by the ana¬lytic solution, a numerical model, simulating the configuration of a three-layered ring (quite commonly encountered in practic¬al applications is validated. The numerical model is then used for a parametric analysis enlightening some crucial aspects of the overall response of the ring.
International Nuclear Information System (INIS)
Bayat, Mehdi; Saleem, M.; Sahari, B.B.; Hamouda, A.M.S.; Mahdi, E.
2009-01-01
Rotating disks have many applications in the aerospace industry such as gas turbines and gears. These disks normally work under thermo mechanical loads. Minimizing the weight of such components can help reduce the overall payload in aerospace industry. For this purpose, a rotating functionally graded (FG) disk with variable thickness under a steady temperature field is considered in this paper. Thermo elastic solutions and the weight of the disk are related to the material grading index and the geometry of the disk. It is found that a disk with parabolic or hyperbolic convergent thickness profile has smaller stresses and displacements compared to a uniform thickness disk. Maximum radial stress due to centrifugal load in the solid disk with parabolic thickness profile may not be at the center unlike uniform thickness disk. Functionally graded disk with variable thickness has smaller stresses due to thermal load compared to those with uniform thickness. It is seen that for a given value of grading index, the FG disk having concave thickness profile is the lightest in weight whereas the FG disk with uniform thickness profile is the heaviest. Also for any given thickness profile, the weight of the FG disk lies in between the weights of the all-metal and the all-ceramic disks.
International Nuclear Information System (INIS)
Zhang Yuru; Xu Xiang; Wang Younian; Bogaerts, Annemie
2012-01-01
A two-dimensional fluid model, including the full set of Maxwell equations, has been developed and applied to investigate the effect of a phase shift between two power sources on the radial uniformity of several plasma characteristics in a hydrogen capacitively coupled plasma. This study was carried out at various frequencies in the range 13.56-200 MHz. When the frequency is low, at 13.56 MHz, the plasma density is characterized by an off-axis peak when both power sources are in-phase (φ = 0), and the best radial uniformity is obtained at φ = π. This trend can be explained because the radial nonuniformity caused by the electrostatic edge effect can be effectively suppressed by the phase-shift effect at a phase difference equal to π. When the frequency rises to 60 MHz, the plasma density profiles shift smoothly from edge-peaked over uniform to centre-peaked as the phase difference increases, due to the pronounced standing-wave effect, and the best radial uniformity is reached at φ = 0.3π. At a frequency of 100 MHz, a similar behaviour is observed, except that the maximum of the plasma density moves again towards the radial edge at the reverse-phase case (φ = π), because of the dominant skin effect. When the frequency is 200 MHz, the bulk plasma density increases significantly with increasing phase-shift values, and a better uniformity is obtained at φ = 0.4π. This is because the density in the centre increases faster than at the radial edge as the phase difference rises, due to the increasing power deposition P z in the centre and the decreasing power density P r at the radial edge. As the phase difference increases to π, the maximum near the radial edge becomes obvious again. This is because the skin effect has a predominant influence on the plasma density under this condition, resulting in a high density at the radial edge. Moreover, the axial ion flux increases monotonically with phase difference, and exhibits similar profiles to the plasma density
Kim, Haksung; Ho Pyeon, Cheol; Lim, Jae-Yong; Misawa, Tsuyoshi
2012-01-01
The effects of silicon cross section and neutron spectrum on the radial uniformity of a Si-ingot are examined experimentally with various neutron spectrum conditions. For the cross section effect, the numerical results using silicon single crystal cross section reveal good agreements with experiments within relative difference of 6%, whereas the discrepancy is approximately 20% in free-gas cross section. For the neutron spectrum effect, the radial uniformity in hard neutron spectrum is found to be more flattening than that in soft spectrum. Copyright © 2011 Elsevier Ltd. All rights reserved.
Radial loads and axial thrusts on centrifugal pumps
International Nuclear Information System (INIS)
Anon.
1986-01-01
The proceedings of a seminar organised by the Power Industries Division of the IMechE are presented in this text. Complete contents: Review of parameters influencing hydraulic forces on centrifugal impellers; The effect of fluid forces at various operation conditions on the vibrations of vertical turbine pumps; A review of the pump rotor axial equilibrium problem - some case studies; Dynamic hydraulic loading on a centrifugal pump impeller; Experimental research on axial thrust loads of double suction centrifugal pumps; A comparison of pressure distribution and radial loads on centrifugal pumps; A theoretical and experimental investigation of axial thrusts within a multi-stage centrifugal pump
Energy Technology Data Exchange (ETDEWEB)
Han, Seung Hak; Nam, Seok Ho; Lee, Je Yull; Song, Seung Hyun; Jeon, Hae Ryong; Baek, Geon Woo; Ko, Tae Kuk [Yonsei University, Seoul (Korea, Republic of); Kang, Hyoung Ku [Korea National University of Transportation, Chungju (Korea, Republic of)
2017-09-15
Current lead is a device that connects the power supply and superconducting magnets. High temperature superconductor (HTS) has lower thermal conductivity and higher current density than normal metal. For these reasons, the heat load can be reduced by replacing the normal metal of the current lead with the HTS. Conventional HTS current lead has same cross-sectional area in the axial direction. However, this is over-designed at the cold-end (4.2 K) in terms of current. The heat load can be reduced by reducing this part because the heat load is proportional to the cross-sectional area. Therefore, in this paper, heat load was calculated from the heat diffusion equation of HTS current leads with uniform and non-uniform cross-sectional areas. The cross-sectional area of the warm-end (65K) is designed considering burnout time when cooling system failure occurs. In cold-end, Joule heat and heat load due to current conduction occurs at the same time, so the cross-sectional area where the sum of the two heat is minimum is obtained. As a result of simulation, current leads for KSTAR TF coils with uniform and non-uniform cross-sectional areas were designed, and it was confirmed that the non-uniform cross-sectional areas could further reduce the heat load.
Tire-rim interface pressure of a commercial vehicle wheel under radial loads: theory and experiment
Wan, Xiaofei; Shan, Yingchun; Liu, Xiandong; He, Tian; Wang, Jiegong
2017-11-01
The simulation of the radial fatigue test of a wheel has been a necessary tool to improve the design of the wheel and calculate its fatigue life. The simulation model, including the strong nonlinearity of the tire structure and material, may produce accurate results, but often leads to a divergence in calculation. Thus, a simplified simulation model in which the complicated tire model is replaced with a tire-wheel contact pressure model is used extensively in the industry. In this paper, a simplified tire-rim interface pressure model of a wheel under a radial load is established, and the pressure of the wheel under different radial loads is tested. The tire-rim contact behavior affected by the radial load is studied and analyzed according to the test result, and the tire-rim interface pressure extracted from the test result is used to evaluate the simplified pressure model and the traditional cosine function model. The results show that the proposed model may provide a more accurate prediction of the wheel radial fatigue life than the traditional cosine function model.
Park, Jinil; Shin, Taehoon; Yoon, Soon Ho; Goo, Jin Mo; Park, Jang-Yeon
2016-05-01
The purpose of this work was to develop a 3D radial-sampling strategy which maintains uniform k-space sample density after retrospective respiratory gating, and demonstrate its feasibility in free-breathing ultrashort-echo-time lung MRI. A multi-shot, interleaved 3D radial sampling function was designed by segmenting a single-shot trajectory of projection views such that each interleaf samples k-space in an incoherent fashion. An optimal segmentation factor for the interleaved acquisition was derived based on an approximate model of respiratory patterns such that radial interleaves are evenly accepted during the retrospective gating. The optimality of the proposed sampling scheme was tested by numerical simulations and phantom experiments using human respiratory waveforms. Retrospectively, respiratory-gated, free-breathing lung MRI with the proposed sampling strategy was performed in healthy subjects. The simulation yielded the most uniform k-space sample density with the optimal segmentation factor, as evidenced by the smallest standard deviation of the number of neighboring samples as well as minimal side-lobe energy in the point spread function. The optimality of the proposed scheme was also confirmed by minimal image artifacts in phantom images. Human lung images showed that the proposed sampling scheme significantly reduced streak and ring artifacts compared with the conventional retrospective respiratory gating while suppressing motion-related blurring compared with full sampling without respiratory gating. In conclusion, the proposed 3D radial-sampling scheme can effectively suppress the image artifacts due to non-uniform k-space sample density in retrospectively respiratory-gated lung MRI by uniformly distributing gated radial views across the k-space. Copyright © 2016 John Wiley & Sons, Ltd.
Orbay, Jorge L; Mijares, Michael R; Berriz, Cecilia G
2016-01-01
When designing a radial head replacement, the magnitude and direction of forces applied across the proximal radio-ulnar joint (PRUJ) and the radiocapitellar joint must be included. These designs often focus on axial loads transmitted to the radial head by the capitellum; however, the radial head also bears a significant transverse force at the PRUJ. Load transmission by the central band of the interosseous ligament induces a force component in a lateral direction perpendicular to the axis of the limb, which is borne by the articular surfaces of the proximal and distal radio-ulnar joints. The objective of this study is to establish the relationship between distally applied axial forces and proximal transverse reaction forces. Five cadaveric, human forearms with intact interosseous membranes were used to measure the magnitude of transversely-directed forces experienced by the radial head during axial loading of the forearm at the lunate fossa. A Mark-10 test stand applied a gradual and continuous axial load on the articular surface of the distal radius. A Mark-10 force gauge measured the resultant transverse force experienced by the radial head in the proximal radioulnar joint. Classical mechanics and static force analysis were applied in order to predict lateral force values that would occur when the interosseous ligament is treated as the major load transmitter between the radius and ulna. Acquired data show that the radial head bears a force in the transverse direction that averages 18% (SD 3.89%) in magnitude of the axial force applied at the wrist. This figure is in close accordance with the predicted value of 22% that was calculated by way of free-body plotting. Physiologic forearm loading results in a clinically significant transverse force component transmitted through the interosseous ligament complex. The existence of transverse forces in the human forearm may explain clinical problems seen after radial head resection and suggest that radial head implants
Thin viscoelastic disc subjected to radial non-stationary loading
Directory of Open Access Journals (Sweden)
Adámek V.
2010-07-01
Full Text Available The investigation of non-stationary wave phenomena in isotropic viscoelastic solids using analytical approaches is the aim of this paper. Concretely, the problem of a thin homogeneous disc subjected to radial pressure load nonzero on the part of its rim is solved. The external excitation is described by the Heaviside function in time, so the nonstationary state of stress is induced in the disc. Dissipative material behaviour of solid studied is represented by the discrete material model of standard linear viscoelastic solid in the Zener configuration. After the derivation of motion equations final form, the method of integral transforms in combination with the Fourier method is used for finding the problem solution. The solving process results in the derivation of integral transforms of radial and circumferential displacement components. Finally, the type of derived functions singularities and possible methods for their inverse Laplace transform are mentioned.
Energy Technology Data Exchange (ETDEWEB)
Altran, A.B.; Lotufo, A.D.P.; Minussi, C.R. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Ilha Solteira, SP (Brazil). Dept. de Engenharia Eletrica], Emails: lealtran@yahoo.com.br, annadiva@dee.feis.unesp.br, minussi@dee.feis.unesp.br; Lopes, M.L.M. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Ilha Solteira, SP (Brazil). Dept. de Matematica], E-mail: mara@mat.feis.unesp.br
2009-07-01
This paper presents a methodology for electrical load forecasting, using radial base functions as activation function in artificial neural networks with the training by backpropagation algorithm. This methodology is applied to short term electrical load forecasting (24 h ahead). Therefore, results are presented analyzing the use of radial base functions substituting the sigmoid function as activation function in multilayer perceptron neural networks. However, the main contribution of this paper is the proposal of a new formulation of load forecasting dedicated to the forecasting in several points of the electrical network, as well as considering several types of users (residential, commercial, industrial). It deals with the MLF (Multimodal Load Forecasting), with the same processing time as the GLF (Global Load Forecasting). (author)
Radial basis function neural network for power system load-flow
International Nuclear Information System (INIS)
Karami, A.; Mohammadi, M.S.
2008-01-01
This paper presents a method for solving the load-flow problem of the electric power systems using radial basis function (RBF) neural network with a fast hybrid training method. The main idea is that some operating conditions (values) are needed to solve the set of non-linear algebraic equations of load-flow by employing an iterative numerical technique. Therefore, we may view the outputs of a load-flow program as functions of the operating conditions. Indeed, we are faced with a function approximation problem and this can be done by an RBF neural network. The proposed approach has been successfully applied to the 10-machine and 39-bus New England test system. In addition, this method has been compared with that of a multi-layer perceptron (MLP) neural network model. The simulation results show that the RBF neural network is a simpler method to implement and requires less training time to converge than the MLP neural network. (author)
Effect of radial head implant shape on joint contact area and location during static loading.
Shannon, Hannah L; Deluce, Simon R; Lalone, Emily A; Willing, Ryan; King, Graham J W; Johnson, James A
2015-04-01
To examine the effect of implant shape on radiocapitellar joint contact area and location in vitro. We used 8 fresh-frozen cadaveric upper extremities. An elbow loading simulator examined joint contact in pronation, neutral rotation, and supination with the elbow at 90° flexion. Muscle tendons were attached to pneumatic actuators to allow for computer-controlled loading to achieve the desired forearm rotation. We performed testing with the native radial head, an axisymmetric implant, a reverse-engineered patient-specific implant, and a population-based quasi-anatomic implant. Implants were inserted using computer navigation. Contact area and location were quantified using a casting technique. We found no significant difference between contact locations for the native radial head and the 3 implants. All of the implants had a contact area lower than the native radial head; however, only the axisymmetric implant was significantly different. There was no significant difference in contact area between implant shapes. The similar contact areas and locations of the 3 implant designs suggest that the shape of the implant may not be important with respect to radiocapitellar joint contact mechanics when placed optimally using computer navigation. Further work is needed to explore the sensitivity of radial head implant malpositioning on articular contact. The lower contact area of the radial head implants relative to the native radial head is similar to previous benchtop studies and is likely the result of the greater stiffness of the implant. Radial head implant shape does not appear to have a pronounced influence on articular contact, and both axisymmetric and anatomic metal designs result in elevated cartilage stress relative to the intact state. Copyright © 2015 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.
International Nuclear Information System (INIS)
Girka, I.A.; Stepanov, K.N.
1990-01-01
Dispersion equation for fast plasma cylinder with longitudinal current including a weak azimuthal magnetic field β 0v is obtained and analyzed on the basis of perturbation theory. Simple asymptotic expressions for S w , S n and σ k are derived under different limiting cases (propagation of small-scale waves with high values of radial wave number, wave in the uniform cylinder, surface mode etc.). 10 refs.; 1 fig
Flow control by combining radial pulsation and rotation of a cylinder in uniform flow
Oualli, H.; Hanchi, S.; Bouabdallah, A.; Gad-El-Hak, M.
2008-11-01
Flow visualizations and hot-wire measurements are carried out to study a circular cylinder undergoing simultaneous radial pulsation and rotation and placed in a uniform flow. The Reynolds number is in the range of 1,000--22,000, for which transition in the shear layers and near wake is expected. Our previous experimental and numerical investigations in this subcritical flow regime have established the existence of an important energy transfer mechanism from the mean flow to the fluctuations. Radial pulsations cause and enhance that energy transfer. Certain values of the amplitude and frequency of the pulsations lead to negative drag (i.e. thrust). The nonlinear interaction between the Magnus effect induced by the steady rotation of the cylinder and the near-wake modulated by the bluff body's pulsation leads to alteration of the omnipresent Kármán vortices and the possibility of optimizing the lift-to-drag ratio as well as the rates of heat and mass transfer. Other useful applications include the ability to enhance or suppress the turbulence intensity, and to avoid the potentially destructive lock-in phenomenon in the wake of bridges, electric cables and other structures.
International Nuclear Information System (INIS)
Stone, I.Z.
1992-01-01
As in-core fuel management designs evolve to meet the demands of increasing energy output, more innovative methods are developed to maintain power peaking within acceptable thermal margin limits. In-core fuel management staff must utilize various loading pattern strategies such as cross-core movement of fuel assemblies, multibatch enrichment schemes, and burnable absorbers as the primary means of controlling the radial power distribution. The utilization of fresh asymmetrically loaded gadolinia-bearing assemblies as a fuel management tool provides an additional means of controlling the radial power distribution. At Siemens Nuclear Power Corporation (SNP), fresh fuel assemblies fabricated with asymmetrically loaded gadolinia-bearing fuel rods have been used successfully for several cycles of reactor operation. Asymmetric assemblies are neutronically modeled using the same tools and models that SNP uses to model symmetrically loaded gadolinia-bearing fuel assemblies. The CASMO-2E code is used to produce the homogenized macroscopic assembly cross sections for the nodal core simulator. Optimum fuel pin locations within the asymmetrical assembly are determined using the pin-by-pin PDQ7 assembly core model for each new assembly design. The optimum pin location is determined by the rod loading that minimizes the peak-to-average pin power
International Nuclear Information System (INIS)
Soliman, S.F.; Gill, S.S.
1979-01-01
Charts are presented giving the elastic stress concentration factors in spherical pressure vessels with pad and integral reinforcement for radial branches subjected to radial load and moment. The effect of all the geometrical parameters is discussed, including the limitations of thin shell theory on the validity of the results. (author)
Directory of Open Access Journals (Sweden)
Mir Hamid Reza Ghoreishy
2014-10-01
Full Text Available This research work is devoted to the simulation of a steel-belted radial tire under different static loads. The nonlinear finite element calculations were performed using the MSC.MARC code, installed on a computer system equipped with a parallel processing technology. Hybrid elements in conjunction with two hyperelastic models, namely Marlow and Yeoh, and rebar layer implemented in surface elements were used for the modeling of rubbery and reinforcing parts, respectively. Linear elastic material models were also used for the modeling of the reinforcing elements including steel cord in belts, polyester cord in carcass and nylon cord in cap ply section. Two-dimensional axisymmetric elements were used for the modeling of rim-mounting and inflation and three-dimensional models were developed for the application of the radial, tangential, lateral and torsional loads. Different finite element models were developed, in which both linear and quadratic elements were used in conjunction with different mesh densities in order to find the optimum finite element model. Based on the results of the load deflection (displacement data, the tire stiffness under radial, tangential, lateral and torsional loads were calculated and compared with their corresponding experimentally measured values. The comparison was verified by the accuracy of the measured radial stiffness. However, due to the neglecting of the stiffness in shear and bending modes in cord-rubber composites, modeled with rebar layer methodology, the difference between computed values and real data are not small enough so that a more robust material models and element formulation are required to be developed.
Directory of Open Access Journals (Sweden)
2006-01-01
Full Text Available This paper highlights the use of the finite element technique for analyzing stress and displacement distributions in wheels of automotive vehicles when subject to the conjoint influence of inflation pressure and radial load. The most commonly used considerations in the design of the rotating body are elucidated. A potentially viable technique for finite element modeling of radial wheel, subjected to loading, is highlighted. The extrinsic influence of inflation pressure on performance of the rotating body, that is, the wheel, is rationalized.
Philosophy, design and testing of a uniform applied load flat plate testing machine
International Nuclear Information System (INIS)
Quirk, A.; Crook, C.
1976-08-01
The presence of a central crack, and its associated plastic zones may significantly affect distribution of the stress applied by a loading machine, to a test plate. As a result the fracture stress may be affected, usually optimistically. Examples of these effects are discussed. The design of a machine in which the load is uniformly applied to the test specimen is described and preliminary test data presented. (author)
Institute of Scientific and Technical Information of China (English)
You-wen LIU; Chao XIE; Chun-zhi JIANG; Qi-hong FANG
2010-01-01
In this paper,the analytical solution of stress field for a strained reinforcement layer bonded to a lip-shaped crack under a remote mode Ⅲ uniform load and a concentrated load is obtained explicitly in the series form by using the technical of conformal mapping and the method of analytic continuation.The effects of material combinations,bond of interface and geometric configurations on interfacial stresses generated by eigenstrain,remote load and concentrated load are studied.The results show that the stress concentration and interfacial stresses can be reduced by rational material combinations and geometric configurations designs for different load forms.
Bhatia, Sanjeev; Civitarese, David M; Turnbull, Travis Lee; LaPrade, Christopher M; Nitri, Marco; Wijdicks, Coen A; LaPrade, Robert F
2016-03-01
Complete radial tears of the medial meniscus have been reported to be functionally similar to a total meniscectomy. At present, there is no consensus on an ideal technique for repair of radial midbody tears of the medial meniscus. Prior attempts at repair with double horizontal mattress suture techniques have led to a reportedly high rate of incomplete healing or healing in a nonanatomic (gapped) position, which compromises the ability of the meniscus to withstand hoop stresses. A newly proposed 2-tunnel radial meniscal repair method will result in decreased gapping and increased ultimate failure loads compared with the double horizontal mattress suture repair technique under cyclic loading. Controlled laboratory study. Ten matched pairs of male human cadaveric knees (average age, 58.6 years; range, 48-66 years) were used. A complete radial medial meniscal tear was made at the junction of the posterior one-third and middle third of the meniscus. One knee underwent a horizontal mattress inside-out repair, while the contralateral knee underwent a radial meniscal repair entailing the same technique with a concurrent novel 2-tunnel repair. Specimens were potted and mounted on a universal testing machine. Each specimen was cyclically loaded 1000 times with loads between 5 and 20 N before experiencing a load to failure. Gap distances at the tear site and failure load were measured. The 2-tunnel repairs exhibited a significantly stronger ultimate failure load (median, 196 N; range, 163-212 N) than did the double horizontal mattress suture repairs (median, 106 N; range, 63-229 N) (P = .004). In addition, the 2-tunnel repairs demonstrated decreased gapping at all testing states (P meniscus significantly decrease the ability of the meniscus to dissipate tibiofemoral loads, predisposing patients to early osteoarthritis. Improving the ability to repair medial meniscal radial tears in a way that withstands cyclic loads and heals in an anatomic position could significantly
Directory of Open Access Journals (Sweden)
M. M. Potsane
2014-01-01
Full Text Available The transport of chemicals through soils to the groundwater or precipitation at the soils surfaces leads to degradation of these resources. Serious consequences may be suffered in the long run. In this paper, we consider macroscopic deterministic models describing contaminant transport in saturated soils under uniform radial water flow backgrounds. The arising convection-dispersion equation given in terms of the stream functions is analyzed using classical Lie point symmetries. A number of exotic Lie point symmetries are admitted. Group invariant solutions are classified according to the elements of the one-dimensional optimal systems. We analyzed the group invariant solutions which satisfy the physical boundary conditions.
Seismic Responses of a Cable-Stayed Bridge with Consideration of Uniform Temperature Load
Directory of Open Access Journals (Sweden)
Junjun Guo
2016-12-01
Full Text Available The effects of temperature load on the dynamic responses of cable-stayed bridges have attracted the attention of researchers in recent years. However, these investigations mainly focus on the influence of temperature on the dynamic characteristics of structures, such as vibration mode and frequency. This paper discusses the effects of uniform temperature changes on the seismic responses of a cable-stayed bridge. A three dimensional finite element model of a cable-stayed bridge using OpenSees is established for nonlinear time history analysis, and uniform temperature load is applied to the prototype bridge before the conducting of seismic excitation. Three ground motion records are selected from the PEER strong motion database based on the design spectrum. Case studies are then performed considering the varying temperature and the connections between the deck and pylons of the bridge. The result shows that the seismic responses of the bridge are significantly increased with the consideration of temperature load. Meanwhile, the types between the deck and pylon also have notable impacts on the seismic responses of the bridge with and without temperature changes. This research could provide a reference for designers during the design phase of cable-stayed brides.
Numerical study of radial stepwise fuel load reshuffling traveling wave reactor
International Nuclear Information System (INIS)
Zhang Dalin; Zheng Meiyin; Tian Wenxi; Qiu Suizheng; Su Guanghui
2015-01-01
Traveling wave reactor is a new conceptual fast breeder reactor, which can adopt natural uranium, depleted uranium and thorium directly to realize the self sustainable breeding and burning to achieve very high fuel utilization fraction. Based on the mechanism of traveling wave reactor, a concept of radial stepwise fuel load reshuffling traveling wave reactor was proposed for realistic application. It was combined with the typical design of sodium-cooled fast reactors, with which the asymptotic characteristics of the inwards stepwise fuel load reshuffling were studied numerically in two-dimension. The calculated results show that the asymptotic k_e_f_f parabolically varies with the reshuffling cycle length, while the burnup increases linearly. The highest burnup satisfying the reactor critical condition is 38%. The power peak shifts from the fuel discharging zone (core centre) to the fuel uploading zone (core periphery) and correspondingly the power peaking factor decreases along with the reshuffling cycle length. In addition, at the high burnup case the axial power distribution close to the core centre displays the M-shaped deformation. (authors)
A METHOD FOR EVALUATION OF NON-UNIFORM RADIANT-CONVECTIVE LOAD ON HUMAN BODY DURING MENTAL WORK
Directory of Open Access Journals (Sweden)
Lenka Prokšová Zuská
2017-10-01
Full Text Available The objective of this study was to develop a documentation for the amendment of the microclimatic part of the Czech Government Regulation, particularly in a non-uniform radiant-convective load evaluation. Changes in regulation were made based on experimental data obtained on a group of experimental individuals in a climatic chamber. One of the objectives of the climatic chamber experiments was to evaluate whether there was a possibility to use an alternative method, which utilizes a new value – stereotemperature, for the assessment. A group of 24 women was exposed to a non-uniform radiant-convective load in a climatic chamber for 1 hour during their computer work. Measurements were divided according to the globe temperature into 3 stages. The physical parameters of air were continuously measured: the air temperature, globe temperature, air velocity, radiant temperature, relative humidity, stereotemperature and physiological parameters. Thermal sensations of experimental subjects were expressed in the seven-point scale according to EN ISO 7730. The thermal sensation correlated very well with the difference of stereotemperature and the globe temperature. The stereotemperature correlated very well with the radiant temperature. In this work, the composed equations were used to develop the limit values for the thermal stress evaluation in the uniform and non-uniform thermal environment at workplaces. It is possible to determine how the body of an exposed person perceives the non-uniform climatic conditions in the indoor environment, by adding the stereotemperature to government regulations.
Numerical Investigation of the Effect of Radial Lip Seal Geometry on Sealing Performance
Tok, G.; Parlar, Z.; Temiz, V.
2018-01-01
Sealing elements are often needed in industry and especially in machine design. With the change and development of machine technology from day to day, sealing elements show continuous development and change in parallel with these developments. Many factors influence the performance of the sealing elements such as shaft surface roughness, radial force, lip geometry etc. In addition, the radial lip seals must have a certain pre-load and interference in order to provide a good sealing. This also affects the friction torque. Researchers are developing new seal designs to reduce friction losses in mechanical systems. In the presented study, the effect of the lip seal geometry on sealing performance will be examined numerically. The numerical model created for this purpose will be verified with experimental data firstly. In the numerical model, shaft and seal will be modeled as hyper-elastic in 2D and 3D. NBR (Nitrile Butadiene Rubber) as seal material will be analyzed for the rotating shaft state at constant speed by applying a uniform radial force.
DEFF Research Database (Denmark)
Moslemian, Ramin; Quispitupa, Amilcar; Berggreen, Christian
2012-01-01
This paper deals with the failure of compression-loaded sandwich panels with an implanted circular face/core debond. Uniform compression tests were conducted on intact sandwich panels with three different types of core material (H130, H250 and PMI) and on similar panels with circular face...
Smith, Karl H.
2002-01-01
A radial wedge flange clamp comprising a pair of flanges each comprising a plurality of peripheral flat wedge facets having flat wedge surfaces and opposed and mating flat surfaces attached to or otherwise engaged with two elements to be joined and including a series of generally U-shaped wedge clamps each having flat wedge interior surfaces and engaging one pair of said peripheral flat wedge facets. Each of said generally U-shaped wedge clamps has in its opposing extremities apertures for the tangential insertion of bolts to apply uniform radial force to said wedge clamps when assembled about said wedge segments.
Analytical examination of a spiral beam scanning method for uniform irradiation
Energy Technology Data Exchange (ETDEWEB)
Fukuda, Mitsuhiro; Okumura, Susumu; Arakawa, Kazuo [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment
1997-03-01
A new circular beam scanning method for uniform irradiation of high-energy, intense ion beams over a large area has been developed. A sweeping speed and a trajectory density in a radial direction are kept constant to obtain uniform fluence distribution. A radial position of a beam spot on a target and an angular frequency of the circular motion are expressed by an irrational function of time. The beam is swept continuously, and a beam trajectory becomes spiral. More than 90 % uniformity of the fluence distribution can been achieved over a large area. (author)
Radial electron beam laser excitation: the REBLE report
International Nuclear Information System (INIS)
Ramirez, J.J.; Prestwich, K.R.
1978-10-01
The results of an investigation of techniques to generate high-power radially converging electron beams and the application of these beams to gas lasers is discussed. The design and performance of the REBLE accelerator that was developed for this program is presented. Reliable operation of the radial diode has been obtained at levels up to 1 MV, 200 kA, and 20 ns. It has been demonstrated that the anode current density can be made uniform to better than 15% over 1000 cm 2 areas with 100 to 250 A/cm 2 intensities. The measured total and spatially resolved energy deposition of this radial electron beam in various gases is compared with Monte Carlo calculations. In most cases, these codes give an accurate description of the beam transport and energy deposition. With the electron beam pumping xenon gas, the amplitude of xenon excimer radiation (1720 A 0 ) was radially uniform to within the experimental uncertainty. The efficiency of converting deposited electron beam energy to xenon excimer radiation was 20%
Kamali, M.; Shamsi, M.; Saidi, A. R.
2018-03-01
As a first endeavor, the effect of nonlinear elastic foundation on the postbuckling behavior of smart magneto-electro-elastic (MEE) composite nanotubes is investigated. The composite nanotube is affected by a non-uniform thermal environment. A typical MEE composite nanotube consists of microtubules (MTs) and carbon nanotubes (CNTs) with a MEE cylindrical nanoshell for smart control. It is assumed that the nanoscale layers of the system are coupled by a polymer matrix or filament network depending on the application. In addition to thermal loads, magneto-electro-mechanical loads are applied to the composite nanostructure. Length scale effects are taken into account using the nonlocal elasticity theory. The principle of virtual work and von Karman's relations are used to derive the nonlinear governing differential equations of MEE CNT-MT nanotubes. Using Galerkin's method, nonlinear critical buckling loads are determined. Various types of non-uniform temperature distribution in the radial direction are considered. Finally, the effects of various parameters such as the nonlinear constant of elastic medium, thermal loading factor and small scale coefficient on the postbuckling of MEE CNT-MT nanotubes are studied.
Parry, Ellis; Kim, Dong-Jin; Castrejón-Pita, Alfonso A.; Elston, Steve J.; Morris, Stephen M.
2018-06-01
This paper investigates the drop-on-demand inkjet printing of a nematic liquid crystal (LC) onto a variety of substrates. Achieving both a well-defined droplet boundary and uniformity of the LC director in printed droplets can be challenging when traditional alignment surfaces are employed. Despite the increasing popularity of inkjet printing LCs, the mechanisms that are involved during the deposition process such as drop impact, wetting and spreading have received very little attention, in the way of experiments, as viable routes for promoting alignment of the resultant LC droplets. In this work, radial alignment of the director and uniformity of the droplet boundary are achieved in combination via the use of a partially-wet polymer substrate, which makes use of the forces and flow generated during droplet impact and subsequent wetting process. Our findings could have important consequences for future LC inkjet applications, including the development of smart inks, printable sensors and lasers.
International Nuclear Information System (INIS)
Wang, Haiqiang; Wang, Penglu; Chen, Xiongbo; Wu, Zhongbiao
2017-01-01
Highlights: • VOSO_4 exhibited better synergistic effect with titanate nanotubes than NH_4VO_3. • Ion-exchange reaction occurs between VOSO_4 and titanate nanotubes. • Ion-exchange resulting in uniformly vanadium distribution on titanate nanotubes. • VOSO_4-based catalyst exhibited impressive SCR activity and alkaline resistance. - Abstract: In this work, protonated titanate nanotubes was performed as a potential useful support and different vanadium precursors (NH_4VO_3 and VOSO_4) were used to synthesize deNO_x catalysts. The results showed that VOSO_4 exhibited better synergistic effect with titanate nanotubes than NH_4VO_3, which was caused by the ion-exchange reaction. Then high loading content of vanadium, uniformly active phase distribution, better dispersion of vanadium, more acid sites, better V"5"+/V"4"+ redox cycles and superior oxygen mobility were achieved. Besides, VOSO_4-based titanate nanotubes catalysts also showed enhanced alkaline resistance than particles (P25) based catalysts. It was strongly associated with its abundant acid sites, large surface area, flexible redox cycles and oxygen transfer ability. For the loading on protonated titanate nanotubes, active metal with cation groups was better precursors than anion ones. V_2O_5/TNTs catalyst was a promising substitute for the commercial vanadium catalysts and the work conducted herein provided a useful idea to design uniformly active phase loaded catalyst.
Gao, Qingfei; Wang, Zonglin; Jia, Hongyu; Liu, Chenguang; Li, Jun; Guo, Binqiang; Zhong, Junfei
2015-01-01
To address the drawback of traditional method of investigating dynamic responses of the continuous girder bridge with uniform cross-section under moving vehicular loads, the orthogonal experimental design method is proposed in this paper. Firstly, some empirical formulas of natural frequencies are obtained by theoretical derivation and numerical simulation. The effects of different parameters on dynamic responses of the vehicle-bridge coupled vibration system are discussed using our own progr...
Energy Technology Data Exchange (ETDEWEB)
Pazirandeh, Ali [Islamic Azad Univ., Tehran (Iran, Islamic Republic of). Science and Research Branch; Hooshyar Mobaraki, Almas
2017-07-15
The safe operation of a reactor is based on feedback models. In this paper we attempted to discuss the influence of a non-uniform radial temperature distribution on the fuel rod temperature coefficient of reactivity. The paper demonstrates that the neutron properties of a reactor core is based on effective temperature of the fuel to obtain the correct fuel temperature feedback. The value of volume-averaged temperature being used in the calculations of neutron physics with feedbacks would result in underestimating the probable event. In the calculation it is necessary to use the effective temperature of the fuel in order to provide correct accounting of the fuel temperature feedback. Fuel temperature changes in different zones of the core and consequently reactivity coefficient change are an important parameter for analysis of transient conditions. The restricting factor that compensates the inserted reactivity is the temperature reactivity coefficient and effective delayed neutron fraction.
Ghaffari, I.; Parhizkar Yaghoobi, M.; Ghannad, M.
2018-01-01
The purpose of this study is to offer a complete solution to analyze the mechanical behavior (bending, buckling and vibration) of Nano-beam under non-uniform loading. Furthermore, the effects of size (nonlocal parameters), non-homogeneity constants, and different boundary conditions are investigated by using this method. The exact solution presented here reduces costs incurred by experiments. In this research, the displacement field obeys the kinematics of the Euler-Bernoulli beam theory and non-local elasticity theory has been used. The governing equations and general boundary conditions are derived for a beam by using energy method. The presented solution enables us to analyze any kind of loading profile and boundary conditions with no limitations. Furthermore, this solution, unlike previous studies, is not a series-solution; hence, there is no limitation prior to existing with the series-solution, nor does it need to check convergence. Based on the developed analytical solution, the influence of size, non-homogeneity and non-uniform loads on bending, buckling and vibration behaviors is discussed. Also, the obtained result is highly accurate and in good agreement with previous research. In theoretical method, the allowable range for non-local parameters can be determined so as to make a major contribution to the reduction of the cost of experiments determining the value of non-local parameters.
International Nuclear Information System (INIS)
Coleman, P.; Rauch, J.; Rix, W.; Thompson, J.; Wilson, R.
1997-01-01
Hammer (1996) and Velikovich (1996) have discussed ways to mitigate the growth of the magneto-Rayleigh-Taylor (MRT) instability in z-pinch (PRS) implosions. They predict that initial mass distributions more complex than a simple annular shell will reduce instability development. Sanford (1996) reported experimental data showing a benefit for a uniform mass distribution compared to a shell; those tests used ''conventional'' load radii of 2.25 and 1.25 cm respectively, and implosion times under 100 ns. However, the instability problem is expected to grow exponentially as the implosion time, or alternatively the initial radius, increases. Thus we made a comparison of a uniform fill load with a shell but at larger radii, 3.6 and 2.5 cm respectively, and at implosion times well above 100 ns. We see nearly a factor of 10X improvement in peak K-shell power and 2X increase in K-shell yield for the uniform mass load. Hence it appears that suitable tailoring of the imploding mass distribution can significantly limit the instability growth
Directory of Open Access Journals (Sweden)
Hao Dong
2015-01-01
Full Text Available In order to implement the uniform load distribution of the power-split transmission system, a pseudostatic model is built. Based on the loaded tooth contact analysis (LTCA technique, the actual meshing process of each gear pair is simulated and the fitting curve of time-varying mesh stiffness is obtained. And then, the torsional angle deformation compatibility conditions are proposed according to the closed-loop characteristic of power flow, which will be combined with the torque equilibrium conditions and elastic support conditions to calculate the transfer torque of each gear pair. Finally, the load-sharing coefficient of the power-split transmission system is obtained, and the influences of the installation errors are analyzed. The results show that the above-mentioned installation errors comprehensively influence the load-sharing characteristics, and the reduction of only one error could not effectively achieve perfect load-sharing characteristics. Allowing for the spline clearance floating and constrained by the radial spacing ring, the influence of the floating pinion is analyzed. It shows that the floating pinion can improve the load-sharing characteristics. Through the comparison between the theoretical and related experimental data, the reasonability and feasibility of the above-proposed method and model are verified.
Static Load Distribution in Ball Bearings
Ricci, Mario
2010-01-01
A numerical procedure for computing the internal loading distribution in statically loaded, single-row, angular-contact ball bearings when subjected to a known combined radial and thrust load is presented. The combined radial and thrust load must be applied in order to avoid tilting between inner and outer rings. The numerical procedure requires the iterative solution of Z + 2 simultaneous nonlinear equations - where Z is the number of the balls - to yield an exact solution for axial and radial deflections, and contact angles. Numerical results for a 218 angular-contact ball bearing have been compared with those from the literature and show significant differences in the magnitudes of the ball loads, contact angles, and the extent of the loading zone.
Evaluation model development for sprinkler irrigation uniformity ...
African Journals Online (AJOL)
A new evaluation method with accompanying software was developed to precisely calculate uniformity from catch-can test data, assuming sprinkler distribution data to be a continuous variable. Two interpolation steps are required to compute unknown water application depths at grid distribution points from radial ...
A visual study of radial inward choked flow of liquid nitrogen.
Hendricks, R. C.; Simoneau, R. J.; Hsu, Y. Y.
1973-01-01
Data and high speed movies were acquired on pressurized subcooled liquid nitrogen flowing radially inward through a 0.0076 cm gap. The stagnation pressure ranged from 0.7 to 4 MN/sq m. Steady radial inward choked flow appears equivalent to steady choked flow through axisymmetric nozzles. Transient choked flows through the radial gap are not uniform and the discharge pattern appears as nonuniform impinging jets. The critical mass flow rate data for the transient case appear different from those for the steady case. On the mass flow rate vs pressure map, the slope and separation of the isotherms appear to be less for transient than for steady radial choked flow.
Energy Technology Data Exchange (ETDEWEB)
Wang, Haiqiang; Wang, Penglu [Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental & Resources Science, Zhejiang University, 310058 Hangzhou (China); Zhejiang Provincial Engineering Research Center of Industrial Boiler & Furnace Flue Gas Pollution Control, Hangzhou 310027 (China); Chen, Xiongbo [South China Institute of Environmental Sciences, Ministry of Environmental Protection, Guangzhou 510655 (China); Wu, Zhongbiao, E-mail: zbwu@zju.edu.cn [Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental & Resources Science, Zhejiang University, 310058 Hangzhou (China); Zhejiang Provincial Engineering Research Center of Industrial Boiler & Furnace Flue Gas Pollution Control, Hangzhou 310027 (China)
2017-02-15
Highlights: • VOSO{sub 4} exhibited better synergistic effect with titanate nanotubes than NH{sub 4}VO{sub 3}. • Ion-exchange reaction occurs between VOSO{sub 4} and titanate nanotubes. • Ion-exchange resulting in uniformly vanadium distribution on titanate nanotubes. • VOSO{sub 4}-based catalyst exhibited impressive SCR activity and alkaline resistance. - Abstract: In this work, protonated titanate nanotubes was performed as a potential useful support and different vanadium precursors (NH{sub 4}VO{sub 3} and VOSO{sub 4}) were used to synthesize deNO{sub x} catalysts. The results showed that VOSO{sub 4} exhibited better synergistic effect with titanate nanotubes than NH{sub 4}VO{sub 3}, which was caused by the ion-exchange reaction. Then high loading content of vanadium, uniformly active phase distribution, better dispersion of vanadium, more acid sites, better V{sup 5+}/V{sup 4+} redox cycles and superior oxygen mobility were achieved. Besides, VOSO{sub 4}-based titanate nanotubes catalysts also showed enhanced alkaline resistance than particles (P25) based catalysts. It was strongly associated with its abundant acid sites, large surface area, flexible redox cycles and oxygen transfer ability. For the loading on protonated titanate nanotubes, active metal with cation groups was better precursors than anion ones. V{sub 2}O{sub 5}/TNTs catalyst was a promising substitute for the commercial vanadium catalysts and the work conducted herein provided a useful idea to design uniformly active phase loaded catalyst.
Tian, Pengyi; Tao, Dashuai; Yin, Wei; Zhang, Xiangjun; Meng, Yonggang; Tian, Yu
2016-09-01
Comprehension of stick-slip motion is very important for understanding tribological principles. The transition from creep-dominated to inertia-dominated stick-slip as the increase of sliding velocity has been described by researchers. However, the associated micro-contact behavior during this transition has not been fully disclosed yet. In this study, we investigated the stick-slip behaviors of two polymethyl methacrylate blocks actively modulated from the creep-dominated to inertia-dominated dynamics through a non-uniform loading along the interface by slightly tilting the angle of the two blocks. Increasing the tilt angle increases the critical transition velocity from creep-dominated to inertia-dominated stick-slip behaviors. Results from finite element simulation disclosed that a positive tilt angle led to a higher normal stress and a higher temperature on blocks at the opposite side of the crack initiating edge, which enhanced the creep of asperities during sliding friction. Acoustic emission (AE) during the stick-slip has also been measured, which is closely related to the different rupture modes regulated by the distribution of the ratio of shear to normal stress along the sliding interface. This study provided a more comprehensive understanding of the effect of tilted non-uniform loading on the local stress ratio, the local temperature, and the stick-slip behaviors.
Modelling and analysis of radial thermal stresses and temperature ...
African Journals Online (AJOL)
A theoretical investigation has been undertaken to study operating temperatures, heat fluxes and radial thermal stresses in the valves of a modern diesel engine with and without air-cavity. Temperatures, heat fluxes and radial thermal stresses were measured theoretically for both cases under all four thermal loading ...
Ultrasonic transducer design for uniform insonation
International Nuclear Information System (INIS)
Harrison, G.H.; Balcer-Kubiczek, E.K.; McCulloch, D.
1984-01-01
Techniques used in transducer development for acoustical imaging have been evaluated for the purpose of producing broad, uniform ultrasonic fields from planar radiators. Such fields should be useful in hyperthermia, physical therapy, and ultrasonic bioeffects studies. Fourier inversion of the circ function yielded a source velocity distribution proportional to (P/r) exp ((-ik/2Z) (2Z/sup 2/+r/sup 2/)) J/sub 1/(krP/Z), where r is the radial source coordinate, k is the wave number, and P is the desired radius of uniform insonation at a depth Z in water. This source distribution can be truncated without significantly degrading the solution. A simpler solution consists of exponentially shading the edge of an otherwise uniformly excited disk transducer. This approach was successfully approximated experimentally
Uniform current density and divergence control in high power extraction ion diodes
International Nuclear Information System (INIS)
Desjarlais, M.P.; Coats, R.S.; Lockner, T.R.; Pointon, T.D.; Johnson, D.J.; Slutz, S.A.; Lemke, R.W.; Cuneo, M.E.; Mehlhorn, T.A.
1996-01-01
A theory of radial beam uniformity in extraction ion diodes is presented. The theory is based on a locally one-dimensional analysis of the diamagnetic compression of magnetic streamlines and the self-consistent determination of the virtual cathode location. The radial dependence of the applied magnetic field is used to determine the critical parameters of this locally one-dimensional treatment. The theory has been incorporated into the ATHETA magnetic field code to allow the rapid evaluation of realistic magnetic field configurations. Comparisons between the theoretical results, simulations with the QUICKSILVER code, and experiments on the PBFA-X accelerator establish the usefulness of this tool for tuning magnetic fields to improve ion beam uniformity. The consequences of poor beam uniformity on the evolution of ion diode instabilities are discussed with supporting evidence from simulations, theory, and experiments. (author). 8 figs., 15 refs
Uniform current density and divergence control in high power extraction ion diodes
International Nuclear Information System (INIS)
Desjarlais, M.P.; Coats, R.S.; Lockner, T.R.; Pointon, T.D.; Johnson, D.J.; Slutz, S.A.; Lemke, R.W.; Cuneo, M.E.; Melhorn, T.A.
1996-01-01
A theory of radial beam uniformity in extraction ion diodes is presented. The theory is based on a locally one dimensional analysis of the diamagnetic compression of magnetic streamlines and the self consistent determination of the virtual cathode location. The radial dependence of the applied magnetic field is used to determine the critical parameters of this locally one dimensional treatment. The theory has been incorporated into the ATHETA magnetic field code to allow the rapid evaluation of realistic magnetic field configurations. Comparisons between the theoretical results, simulations with the QUICKSILVER code, and experiments on the PBFA-X accelerator establish the usefulness of this tool for tuning magnetic fields to improve ion beam uniformity. The consequences of poor beam uniformity on the evolution of ion diode instabilities are discussed with supporting evidence from simulations, theory, and experiments
Uniform current density and divergence control in high power extraction ion diodes
Energy Technology Data Exchange (ETDEWEB)
Desjarlais, M P; Coats, R S; Lockner, T R; Pointon, T D; Johnson, D J; Slutz, S A; Lemke, R W; Cuneo, M E; Mehlhorn, T A [Sandia Labs., Albuquerque, NM (United States)
1997-12-31
A theory of radial beam uniformity in extraction ion diodes is presented. The theory is based on a locally one-dimensional analysis of the diamagnetic compression of magnetic streamlines and the self-consistent determination of the virtual cathode location. The radial dependence of the applied magnetic field is used to determine the critical parameters of this locally one-dimensional treatment. The theory has been incorporated into the ATHETA magnetic field code to allow the rapid evaluation of realistic magnetic field configurations. Comparisons between the theoretical results, simulations with the QUICKSILVER code, and experiments on the PBFA-X accelerator establish the usefulness of this tool for tuning magnetic fields to improve ion beam uniformity. The consequences of poor beam uniformity on the evolution of ion diode instabilities are discussed with supporting evidence from simulations, theory, and experiments. (author). 8 figs., 15 refs.
Axial and radial velocities in the creeping flow in a pipe
Directory of Open Access Journals (Sweden)
Zuykov Andrey L'vovich
2014-05-01
Full Text Available The article is devoted to analytical study of transformation fields of axial and radial velocities in uneven steady creeping flow of a Newtonian fluid in the initial portion of the cylindrical channel. It is shown that the velocity field of the flow is two-dimensional and determined by the stream function. The article is a continuation of a series of papers, where normalized analytic functions of radial axial distributions in uneven steady creeping flow in a cylindrical tube with azimuthal vorticity and stream function were obtained. There is Poiseuille profile for the axial velocity in the uniform motion of a fluid at an infinite distance from the entrance of the pipe (at x = ∞, here taken equal to zero radial velocity. There is uniform distribution of the axial velocity in the cross section at the tube inlet at x = 0, at which the axial velocity is constant along the current radius. Due to the axial symmetry of the flow on the axis of the pipe (at r = 0, the radial velocities and the partial derivative of the axial velocity along the radius, corresponding to the condition of the soft function extremum, are equal to zero. The authors stated vanishing of the velocity of the fluid on the walls of the pipe (at r = R , where R - radius of the tube due to its viscous sticking and tightness of the walls. The condition of conservation of volume flow along the tube was also accepted. All the solutions are obtained in the form of the Fourier - Bessel. It is shown that the hydraulic losses at uniform creeping flow of a Newtonian fluid correspond to Poiseuille - Hagen formula.
Peak load-impulse characterization of critical pulse loads in structural dynamics
International Nuclear Information System (INIS)
Abrahamson, G.R.; Lindberg, H.E.
1975-01-01
In presenting the characterization scheme, some general features are described first. A detailed analysis is given for the rigid-plastic system of one degree of freedom to illustrate the calculation of critical load curves in terms of peak load and impulse. This is followed by the presentation of critical load curves for uniformly loaded rigid-plastic beams and plates and for dynamic buckling of cylindrical shells under uniform lateral loads. The peak load-impulse characterization of critical pulse loads is compared with the dynamic load factor characterization, and some aspects of the history of the peak load-pulse scheme are presented. (orig./HP) [de
Directory of Open Access Journals (Sweden)
Andreev Vladimir Igorevich
2018-01-01
Full Text Available Subject: one of the promising trends in the development of structural mechanics is the development of methods for solving problems in the theory of elasticity for bodies with continuous inhomogeneity of any deformation characteristics: these methods make it possible to use the strength of the material most fully. In this paper, we consider the two-dimensional problem for the case when a vertical, locally distributed load acts on the hemisphere and the inhomogeneity is caused by the influence of the temperature field. Research objectives: derive governing system of equations in spherical coordinates for determination of the stress state of the radially inhomogeneous hemispherical shell under locally distributed vertical load. Materials and methods: as a mechanical model, we chose a thick-walled reinforced concrete shell (hemisphere with inner and outer radii a and b, respectively, b > a. The shell’s parameters are a = 3.3 m, b = 4.5 m, Poisson’s ratio ν = 0.16; the load parameters are f = 10MPa - vertical localized load distributed over the outer face, θ0 = 30°, temperature on the internal surface of the shell Ta = 500 °C, temperature on the external surface of the shell Tb = 0 °C. The resulting boundary-value problem (a system of differential equations with variable coefficients is solved using the Maple software package. Results: maximal compressive stresses σr with allowance for material inhomogeneity are reduced by 10 % compared with the case when the inhomogeneity is ignored. But it is not so important compared with a 3-fold decrease in the tensile stress σθ on the inner surface and a 2-fold reduction in the tensile stress σθ on the outer surface of the hemisphere as concretes generally have a tensile strength substantially smaller than the compressive strength. Conclusions: the method presented in this article makes it possible to reduce the deformation characteristics of the material, i.e. it leads to a reduction in stresses
International Nuclear Information System (INIS)
Liu, K.C.
1975-01-01
Two tubular specimens of type 304 stainless steel with uniform thin walls were subjected to a program of segmental combined tension/compression and torsion loadings at room temperature. A proportional, or radial, loading into the plastic range was initially applied to each specimen. Two nonproportional (nonradial) loadings along straight line segments for which neither the loading paths nor their linear extrapolations passed through the origin of the stress space were then applied. The axial and torsional stress-strain curves for these segmental prestress loadings were plotted. Hence, the stress-strain response characteristics for nonproportional loadings as well as for proportional loading can be studied. In addition, the axial and torsional plastic strain components were calculated, and the total plastic strain trajectories were plotted in a plastic strain space. Finally, using results from a detailed study of yield surfaces, which was performed for the first specimen, a spectrum of initial and subsequent yield curves corresponding to the segmental prestress loadings is presented. (U.S.)
MODERATOR ELEMENTS FOR UNIFORM POWER NUCLEAR REACTOR
Balent, R.
1963-03-12
This patent describes a method of obtaining a flatter flux and more uniform power generation across the core of a nuclear reactor. The method comprises using moderator elements having differing moderating strength. The elements have an increasing amount of the better moderating material as a function of radial and/or axial distance from the reactor core center. (AEC)
Directory of Open Access Journals (Sweden)
Yiqi Liu
2015-04-01
Full Text Available The rational power sharing among different interface converters should be determined by the converter capacity. In order to guarantee that each converter operates at the ideal condition, considering the radial and mesh configuration, a modified strategy for load power sharing accuracy enhancement in droop-controlled DC microgrid is proposed in this paper. Two compensating terms which include averaging output power control and averaging DC voltage control of neighboring converters are employed. Since only the information of the neighboring converter is used, the complexity of the communication network can be reduced. The rational distribution of load power for different line resistance conditions is realized by using modified droop control that can be regarded as a distributed approach. Low bandwidth communication is used for exchanging sampled information between different converters. The feasibility and effectiveness of the proposed method for different network configurations and line resistances under different communication delay is analyzed in detail. Simulation results derived from a DC microgrid with three converters is implemented in MATLAB/Simulink to verify the proposed approach. Experimental results from a 3 × 10 kW prototype also show the performance of the proposed modified droop control scheme.
On The Dynamic Analysis of Non-Uniform Beams Under Uniformly ...
African Journals Online (AJOL)
... the non-uniform continuous beam was replaced by a non-continuous (discrete) system made up of beam elements. The modified elemental and overall stiffness, and mass matrices, the elemental and overall centripetal acceleration matrices as well as the load vector were derived. Next, the Newmark's direct integration ...
Post-Buckling Strength of Uniformly Compressed Plates
Bakker, M.C.M.; Rosmanit, M.; Hofmeyer, H.; Camotim, D; Silvestre, N; Dinis, P.B.
2006-01-01
In this paper it is discussed how existing analytical and semi-analytical formulas for describing the elastic-post-buckling behavior of uniformly compressed square plates with initial imperfections, for loads up to three times the buckling load can be simplified and improved. For loads larger than
Wang, Xu; Schiavone, Peter
2018-06-01
We consider a confocally coated rigid elliptical inclusion, loaded by a couple and introduced into a remote uniform stress field. We show that uniform interfacial and hoop stresses along the inclusion-coating interface can be achieved when the two remote normal stresses and the remote shear stress each satisfy certain conditions. Our analysis indicates that: (i) the uniform interfacial tangential stress depends only on the area of the inclusion and the moment of the couple; (ii) the rigid-body rotation of the rigid inclusion depends only on the area of the inclusion, the coating thickness, the shear moduli of the composite and the moment of the couple; (iii) for given remote normal stresses and material parameters, the coating thickness and the aspect ratio of the inclusion are required to satisfy a particular relationship; (iv) for prescribed remote shear stress, moment and given material parameters, the coating thickness, the size and aspect ratio of the inclusion are also related. Finally, a harmonic rigid inclusion emerges as a special case if the coating and the matrix have identical elastic properties.
Energy Technology Data Exchange (ETDEWEB)
Senatore, Giacomo [Department of Aerospace Engineering, Universita di Pisa, Pisa 56122 (Italy); Davis, Sean; Jacobs, Gustaaf, E-mail: gjacobs@mail.sdsu.edu [Department of Aerospace Engineering and Engineering Mechanics, San Diego State University, San Diego, 92182 California (United States)
2015-03-15
The effect of non-uniformity in bulk particle mass loading on the linear development of a particle-laden shear layer is analyzed by means of a stochastic Eulerian-Eulerian model. From the set of governing equations of the two-fluid model, a modified Rayleigh equation is derived that governs the linear growth of a spatially periodic disturbance. Eigenvalues for this Rayleigh equation are determined numerically using proper conditions at the co-flowing gas and particle interface locations. For the first time, it is shown that non-uniform loading of small-inertia particles (Stokes number (St) <0.2) may destabilize the inviscid mixing layer development as compared to the pure-gas flow. The destabilization is triggered by an energy transfer rate that globally flows from the particle phase to the gas phase. For intermediate St (1 < St < 10), a maximum stabilizing effect is computed, while at larger St, two unstable modes may coexist. The growth rate computations from linear stability analysis are verified numerically through simulations based on an Eulerian-Lagrangian (EL) model based on the inviscid Euler equations and a point particle model. The growth rates found in numerical experiments using the EL method are in very good agreement with growth rates from the linear stability analysis and validate the destabilizing effect induced by the presence of particles with low St.
DEFF Research Database (Denmark)
Tsakadze, Erekle; Ostrikov, K.N.; Tsakadze, Z.L.
2004-01-01
) discharge modes using two miniature magnetic probes. It is shown that the radial uniformity and depth of the rf power deposition can be improved as compared with conventional sources of inductively coupled plasmas with external flat spiral ("pancake") antennas. Relatively deeper rf power deposition...... in the plasma source results in more uniform profiles of the optical emission intensity, which indicates on the improvement of the plasma uniformity over large chamber volumes. The results of the numerical modeling of the radial magnetic field profiles are found in a reasonable agreement with the experimental...
Wang, Xiao; Wen, Zhijie; Jiang, Yujing; Huang, Hao
2018-03-01
The mechanical and acoustic emission characteristics of rock-like materials under non-uniform loads were investigated by means of a self-developed mining-induced stress testing system and acoustic emission monitoring system. In the experiments, the specimens were divided into three regions and different initial vertical stresses and stress loading rates were used to simulate different mining conditions. The mechanical and acoustic emission characteristics between regions were compared, and the effects of different initial vertical stresses and different stress loading rates were analysed. The results showed that the mechanical properties and acoustic emission characteristics of rock-like materials can be notably localized. When the initial vertical stress and stress loading rate are fixed, the peak strength of region B is approximately two times that of region A, and the maximum acoustic emission hit value of region A is approximately 1-2 times that of region B. The effects of the initial vertical stress and stress loading rate on the peck strain, maximum hit value, and occurrence time of the maximum hit are similar in that when either of the former increase, the latter all decrease. However, peck strength will increase with the increase in loading rate and decrease with the increase in initial vertical stress. The acoustic emission hits can be used to analyse the damage in rock material, but the number of acoustic emission hits cannot be used alone to determine the degree of rock damage directly.
Blade bowing effects on radial equilibrium of inlet flow in axial compressor cascades
Directory of Open Access Journals (Sweden)
Han XU
2017-10-01
Full Text Available The circumferentially averaged equation of the inlet flow radial equilibrium in axial compressor was deduced. It indicates that the blade inlet radial pressure gradient is closely related to the radial component of the circumferential fluctuation (CF source item. Several simplified cascades with/without aerodynamic loading were numerically studied to investigate the effects of blade bowing on the inlet flow radial equilibrium. A data reduction program was conducted to obtain the CF source from three-dimensional (3D simulation results. Flow parameters at the passage inlet were focused on and each term in the radial equilibrium equation was discussed quantitatively. Results indicate that the inviscid blade force is the inducement of the inlet CF due to geometrical asymmetry. Blade bowing induces variation of the inlet CF, thus changes the radial pressure gradient and leads to flow migration before leading edge (LE in the cascades. Positive bowing drives the inlet flow to migrate from end walls to mid-span and negative bowing turns it to the reverse direction to build a new equilibrium. In addition, comparative studies indicate that the inlet Mach number and blade loading can efficiently impact the effectiveness of blade bowing on radial equilibrium in compressor design.
Optical cage generated by azimuthal- and radial-variant vector beams.
Man, Zhongsheng; Bai, Zhidong; Li, Jinjian; Zhang, Shuoshuo; Li, Xiaoyu; Zhang, Yuquan; Ge, Xiaolu; Fu, Shenggui
2018-05-01
We propose a method to generate an optical cage using azimuthal- and radial-variant vector beams in a high numerical aperture optical system. A new kind of vector beam that has azimuthal- and radial-variant polarization states is proposed and demonstrated theoretically. Then, an integrated analytical model to calculate the electromagnetic field and Poynting vector distributions of the input azimuthal- and radial-variant vector beams is derived and built based on the vector diffraction theory of Richards and Wolf. From calculations, a full polarization-controlled optical cage is obtained by simply tailoring the radial index of the polarization, the uniformity U of which is up to 0.7748, and the cleanness C is zero. Additionally, a perfect optical cage can be achieved with U=1, and C=0 by introducing an amplitude modulation; its magnetic field and energy flow are also demonstrated in detail. Such optical cages may be helpful in applications such as optical trapping and high-resolution imaging.
Effects of Radial Reflector Composition on Core Reactivity and Peak Power
International Nuclear Information System (INIS)
Park, Sang Yoon; Lee, Kyung Hoon; Song, Jae Seung
2007-10-01
The effects of radial SA-240 alloy shroud on core reactivity and peak power are evaluated. The existence of radial SA-240 alloy shroud makes reflector water volume decrease, so the thermal absorption cross section of radial reflector is lower than without SA-240 alloy shroud case. Finally, the cycle length is increased from 788 EFPD to 845 EFPD and the peak power is decreased from 1.66 to 1.49. In the case of without SA-240 alloy shroud, a new core loading pattern search has been performed. For the guarantee of the same equivalent cycle length of with SA-240 alloy shroud case, the enrichment of U-235 should be increased from 4.22 w/o to 4.68 w/o. The nuclear key safety parameters of new core loading pattern have been calculated and recorded for the future
Effects of Radial Reflector Composition on Core Reactivity and Peak Power
Energy Technology Data Exchange (ETDEWEB)
Park, Sang Yoon; Lee, Kyung Hoon; Song, Jae Seung
2007-10-15
The effects of radial SA-240 alloy shroud on core reactivity and peak power are evaluated. The existence of radial SA-240 alloy shroud makes reflector water volume decrease, so the thermal absorption cross section of radial reflector is lower than without SA-240 alloy shroud case. Finally, the cycle length is increased from 788 EFPD to 845 EFPD and the peak power is decreased from 1.66 to 1.49. In the case of without SA-240 alloy shroud, a new core loading pattern search has been performed. For the guarantee of the same equivalent cycle length of with SA-240 alloy shroud case, the enrichment of U-235 should be increased from 4.22 w/o to 4.68 w/o. The nuclear key safety parameters of new core loading pattern have been calculated and recorded for the future.
Kumar Sharma, A.; Murty, V. V. S. N.
2014-12-01
The distribution system is the final link between bulk power system and consumer end. A distinctive load flow solution method is used for analysis of the load flow of radial and weakly meshed network based on Kirchhoff's Current Law (KCL) and KVL. This method has excellent convergence characteristics for both radial as well as weakly meshed structure and is based on bus injection to branch current and branch-current to bus-voltage matrix. The main contribution of the paper is: (i) an analysis has been carried out for a weekly mesh network considering number of loops addition and its impact on the losses, kW and kVAr requirements from a system, and voltage profile, (ii) different load models, realistic ZIP load model and load growth impact on losses, voltage profile, kVA and kVAr requirements, (iii) impact of addition of loops on losses, voltage profile, kVA and kVAr requirements from substation, and (iv) comparison of system performance with radial distribution system. Voltage stability is a major concern in planning and operation of power systems. This paper also includes identifying the closeness critical bus which is the most sensitive to the voltage collapse in radial distribution networks. Node having minimum value of voltage stability index is the most sensitive node. Voltage stability index values are computed for meshed network with number of loops added in the system. The results have been obtained for IEEE 33 and 69 bus test system. The results have also been obtained for radial distribution system for comparison.
Fiber optic based optical tomography sensor for monitoring plasma uniformity
International Nuclear Information System (INIS)
Benck, Eric C.; Etemadi, Kasra
2001-01-01
A new type of fiber optic based optical tomography sensor has been developed for in situ monitoring of plasma uniformity. Optical tomography inverts optical emission measurements into the actual plasma distribution without assuming radial symmetry. The new sensor is designed to operate with only two small windows and acquire the necessary data in less than a second. Optical tomography is being tested on an ICP-GEC RF plasma source. Variations in plasma uniformity are measured as a function of different plasma conditions
International Nuclear Information System (INIS)
Ochoa Valero, R.; Garcia-Herranz, N.; Aragones, J. M.
2010-01-01
The aim of this study is to evaluate the minority actinides transmutation in sodium fast reactors (SFR) assuming a uniform load pattern. It is determined the isotopic evolution of the actinides along burn, and the evolution of the reactivity and the reactivity coefficients. For that, it is used the MCNPX neutron transport code coupled with the inventory code CINDER90.
Energy Technology Data Exchange (ETDEWEB)
Yi, Junhui; Zhang, Shengsen; Wang, Hongjuan; Yu, Hao; Peng, Feng, E-mail: cefpeng@scut.edu.cn
2014-12-15
Graphical abstract: Uniformly dispersed Ag nanoparticles (NPs) were successfully loaded on both the outer and inner surface of the TiO{sub 2} nanotube arrays (NTs) through a simple polyol method, which exhibited the enhanced photoelectrochemical and photocatalytic performances under visible-light irradiation due to the more effective separation of photo-generated electron–hole pairs and faster interfacial charge transfer. - Highlights: • Highly dispersed Ag nanoparticles (NPs) are successfully prepared by polyol method. • Ag NPs are uniformly loaded on the surface of the TiO{sub 2} nanotube arrays (NTs). • Ag/TiO{sub 2}-NTs exhibit the enhanced photocatalytic activity under visible-light. • The enhanced photocurrent is explained by electrochemical impedance spectroscopy. - Abstract: Uniformly dispersed Ag nanoparticles (NPs) were successfully loaded on both the outer and inner surface of the TiO{sub 2} nanotube arrays (NTs) through a simple polyol method. The as-prepared Ag/TiO{sub 2}-NTs were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and UV–vis diffusion reflectance spectroscopy. Photoelectrochemical behaviors were investigated via photocurrent response and electrochemical impedance spectroscopy (EIS). Photocatalytic activity of Ag/TiO{sub 2}-NTs was evaluated by degradation of acid orange II under visible light irradiation. The results showed that photocatalytic efficiency of Ag/TiO{sub 2}-NTs is more than 5 times higher than that of pure TiO{sub 2} NTs. Comparing with the electrochemical deposition method, the photocatalytic activity of Ag/TiO{sub 2}-NTs prepared by polyol method has been obviously increased.
The history, development and application of a uniformly applied load wide plate testing machine
International Nuclear Information System (INIS)
Quirk, A.; Bevitt, E.
1989-01-01
The paper describes early attempts to use a rigid end wide plate testing machine to investigate the behaviour of centre cracked flat plates. Confusing and inconsistent results arising from the above tests lead to a detailed investigation of the loading characteristics of rigid end machines in general and the difficulties which can arise in the interpretation of data obtained by the use of such machines. In order to overcome the above difficulties which stem largely from uneven load distribution, a versatile testing machine was designed which by use of cheap and easily obtainable components allows the application of a uniformly distributed applied load to a centre cracked test plate. The machine which was commissioned in its original form in 1975 was initially capable of testing plate of 820 mm width and 25 or 48 mm thickness up to maximum stress levels of 488 or 254 MPa respectively. The ease of adaptability of the machine has since permitted its capacity to be increased to handle plate up to 2032 mm wide and 76 mm thickness and by use of double-banked hydraulic jacks stress levels up to 350 MPa can be achieved on plate of these dimensions. The configuration of the machine allows adequate access for strain gauging, crack tip observation and measurements, and temperature control, tests having been conducted in the temperature range -40 0 C to 290 0 C. Advantages and potential for further development of the machine are given together with details of two of a number of fracture studies which have been conducted since its commissioning. (orig.)
Experimental and theoretical study of friction torque from radial ball bearings
Geonea, Ionut; Dumitru, Nicolae; Dumitru, Ilie
2017-10-01
In this paper it is presented a numerical simulation and an experimental study of total friction torque from radial ball bearings. For this purpose it is conceived a virtual CAD model of the experimental test bench for bearing friction torque measurement. The virtual model it is used for numerical simulation in Adams software, that allows dynamic study of multi-body systems and in particularly with facility Adams Machinery of dynamic behavior of machine parts. It is manufactured an experimental prototype of the test bench for radial ball bearings friction torque measurement. In order to measure the friction torque of the tested bearings it is used an equal resistance elastic beam element, with strain gauge transducer to measure bending deformations. The actuation electric motor of the bench has the shaft mounted on two bearings and the motor housing is fixed to the free side of the elastic beam, which is bended by a force proportional with the total friction torque. The beam elastic element with strain gauge transducer is calibrated in order to measure the force occurred. Experimental determination of the friction torque is made for several progressive radial loads. It is established the correlation from the friction torque and bearing radial load. The bench allows testing of several types and dimensions of radial bearings, in order to establish the bearing durability and of total friction torque.
The effects of load drop, uniform load and concentrated loads on waste tanks
International Nuclear Information System (INIS)
Marusich, R.M. Westinghouse Hanford
1996-01-01
This document provides the supporting calculations performed by others specifically for the TWRS FSAR and more detailed summaries of the important references issued in the past regarding the effects of various loads
On use of radial evanescence remain term in kinematic hardening
International Nuclear Information System (INIS)
Geyer, P.
1995-10-01
A fine modelling of the material' behaviour can be necessary to study the mechanical strength of nuclear power plant' components under cyclic loads. Ratchetting is one of the last phenomena for which numerical models have to be improved. We discuss in this paper on use of radial evanescence remain term in kinematic hardening to improve the description of ratchetting in biaxial loading tests. It's well known that Chaboche elastoplastic model with two non linear kinematic hardening variables initially proposed by Armstrong and Frederick, usually over-predicts accumulation of ratchetting strain. Burlet and Cailletaud proposed in 1987 a non linear kinematic rule with a radial evanescence remain term. The two models lead to identical formulation for proportional loadings. In the case of a biaxial loading test (primary+secondary loading), Burlet and Cailletaud model leads to accommodation, when Chaboche one's leads to ratchetting with a constant increment of strain. So we can have an under-estimate with the first model and an over-estimate with the second. An easy method to improve the description of ratchetting is to combine the two kinematic rules. Such an idea is already used by Delobelle in his model. With analytical results in the case of tension-torsion tests, we show in a first part of the paper, the interest of radial evanescence remain term in the non linear kinematic rule to describe ratchetting: we give the conditions to get adaptation, accommodation or ratchetting and the value of the strain increment in the last case. In the second part of the paper, we propose to modify the elastoplastic Chaboche model by coupling the two types of hardening by means of two scalar parameters which can be identified independently on biaxial loading tests. Identification of these two parameters returns to speculate on the directions of strain in order to adjust the ratchetting to experimental observations. We use the experimental results on the austenitic steel 316L at room
Petersen, Dick; Howard, Carl; Sawalhi, Nader; Moazen Ahmadi, Alireza; Singh, Sarabjeet
2015-01-01
A method is presented for calculating and analyzing the quasi-static load distribution and varying stiffness of a radially loaded double row bearing with a raceway defect of varying depth, length, and surface roughness. The method is applied to ball bearings on gearbox and fan test rigs seeded with line or extended outer raceway defects. When balls pass through the defect and lose all or part of their load carrying capacity, the load is redistributed between the loaded balls. This includes balls positioned outside the defect such that good raceway sections are subjected to increased loading when a defect is present. The defective bearing stiffness varies periodically at the ball spacing, and only differs from the good bearing case when balls are positioned in the defect. In this instance, the stiffness decreases in the loaded direction and increases in the unloaded direction. For an extended spall, which always has one or more balls positioned in the defect, this results in an average stiffness over the ball spacing period that is lower in the loaded direction in comparison to both the line spall and good bearing cases. The variation in bearing stiffness due to the defect produces parametric excitations of the bearing assembly. The qualitative character of the vibration response correlates to the character of the stiffness variations. Rapid stiffness changes at a defect exit produce impulses. Slower stiffness variations due to large wavelength waviness features in an extended spall produce low frequency excitation which results in defect components in the velocity spectra. The contact forces fluctuate around the quasi-static loads on the balls, with rapid stiffness changes producing high magnitude impulsive force fluctuations. Furthermore, it is shown that analyzing the properties of the dynamic model linearized at the quasi-static solutions provides greater insight into the time-frequency characteristics of the vibration response. This is demonstrated by relating
2010-03-01
blade. Radial Work Redistribution Axial flow compressors do not have uniform blade loading in the radial direction. The work redistribution model... Loading Factor vs. Axial Distance ................................................. 270 Figure 3.293 Change in Blade Incidence Angle from Dry vs...exercised first to load the high pressure Figure 3.9 Schematic of the Mixed Flow Turbofan Compression System Modeled AEDC-TR-09-T-19 48
Two dimensional radial gas flows in atmospheric pressure plasma-enhanced chemical vapor deposition
Kim, Gwihyun; Park, Seran; Shin, Hyunsu; Song, Seungho; Oh, Hoon-Jung; Ko, Dae Hong; Choi, Jung-Il; Baik, Seung Jae
2017-12-01
Atmospheric pressure (AP) operation of plasma-enhanced chemical vapor deposition (PECVD) is one of promising concepts for high quality and low cost processing. Atmospheric plasma discharge requires narrow gap configuration, which causes an inherent feature of AP PECVD. Two dimensional radial gas flows in AP PECVD induces radial variation of mass-transport and that of substrate temperature. The opposite trend of these variations would be the key consideration in the development of uniform deposition process. Another inherent feature of AP PECVD is confined plasma discharge, from which volume power density concept is derived as a key parameter for the control of deposition rate. We investigated deposition rate as a function of volume power density, gas flux, source gas partial pressure, hydrogen partial pressure, plasma source frequency, and substrate temperature; and derived a design guideline of deposition tool and process development in terms of deposition rate and uniformity.
Experimental feasibility study of radial injection cooling of three-pad radial air foil bearings
Shrestha, Suman K.
referenced to the rotor surface speed for radial injection cooling. The mass flow rates for the radial injection were 0.032, 0.0432, 0.054 and 0.068 Kg/min, which result in average injection speed of 150, 200, 250 and 300% of rotor surface speed. Several thermocouples were attached at various circumferential directions of the bearing sleeve, two plenums, bearing holder and ball bearing housings to collect the temperature data of the bearing at 30krpm under 10lb of load. Both axial cooling and radial injection are effective cooling mechanism and effectiveness of both cooling methods is directly proportional to the total mass flow rates. However, axial cooling is slightly more efficient in controlling the average temperature of the bearing sleeve, but results in higher thermal gradient of the shaft along the axial direction and also higher thermal gradient of the bearing sleeve along the circumferential direction compared to the radial injection cooling. The smaller thermal gradient of the radial injection cooling is due to the direct cooling effect of the shaft by impinging jets. While the axial cooling has an effect on only the bearing, the radial injection has a cooling effect on both the bearing sleeve and shaft. It is considered the radial injection cooling needs to be further optimized in terms of number of injection holes and their locations.
Distortion of magnetic field lines caused by radial displacements of ITER toroidal field coils
Energy Technology Data Exchange (ETDEWEB)
Amoskov, V.M., E-mail: sytch@niiefa.spb.su [D.V. Efremov Scientific Research Institute of Electrophysical Apparatus, St. Petersburg (Russian Federation); Gribov, Y.V. [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St Paul Lez Durance Cedex (France); Lamzin, E.A.; Sytchevsky, S.E. [D.V. Efremov Scientific Research Institute of Electrophysical Apparatus, St. Petersburg (Russian Federation)
2017-05-15
An assessment of distortions of ideal (circle) field lines caused by random radial displacements of the TF coils by |∆R| ≤ 5 mm has been performed from the statistical analysis assuming a uniform probability density function for displacements.
Rupture of posterior cruciate ligament leads to radial displacement of the medial meniscus.
Zhang, Can; Deng, Zhenhan; Luo, Wei; Xiao, Wenfeng; Hu, Yihe; Liao, Zhan; Li, Kanghua; He, Hongbo
2017-07-11
To explore the association between the rupture of posterior cruciate ligament (PCL) and the radial displacement of medial meniscus under the conditions of different flexion and various axial loads. The radial displacement value of medial meniscus was measured for the specimens of normal adult knee joints, including 12 intact PCLs, 6 ruptures of the anterolateral bundle (ALB), 6 ruptures of the postmedial bundle (PMB), and 12 complete ruptures. The measurement was conducted at 0°, 30°, 60°, and 90° of knee flexion angles under 200 N, 400 N, 600 N, 800 N and 1000 N of axial loads respectively. The displacement values of medial meniscus of the ALB rupture group increased at 0° flexion under 800 N and 1000 N, and at 30°, 60° and 90° flexion under all loads in comparison with the PCL intact group. The displacement values of the PMB rupture group was higher at 0° and 90° flexion under all loads, and at 30° and 60° flexion under 800 N and 1000 N loads. The displacement of the PCL complete rupture group increased at all flexion angles under all loads. Either partial or complete rupture of the PCL can increase in the radial displacement of the medial meniscus, which may explain the degenerative changes that occuring in the medial meniscus due to PCL injury. Therefore, early reestablishment of the PCL is necessarily required in order to maintain stability of the knee joint after PCL injury.
Analysis of influence of the radial electric field on turbulent transport in tandem mirror plasma
International Nuclear Information System (INIS)
Khvesyuk, Vladimir I.; Chirkov, Alexei Yu.; Pshenichnikov, Anton A.
2000-01-01
The model of anomalous transport in cylindrical non-uniform steady state plasma in uniform magnetic field under the influence of many mode drift wave oscillations is suggested. The effect of anomalous transport suppression due to radial electric field is studied, and physical picture of H mode in plasma of GAMMA-10 tandem mirror device is considered. Presented theoretical and numerical results agree with the experimental data obtained on GAMMA-10. (author)
Meng, Qingxin; Hu, Xiangyun; Pan, Heping; Xi, Yufei
2018-04-01
We propose an algorithm for calculating all-time apparent resistivity from transient electromagnetic induction logging. The algorithm is based on the whole-space transient electric field expression of the uniform model and Halley's optimisation. In trial calculations for uniform models, the all-time algorithm is shown to have high accuracy. We use the finite-difference time-domain method to simulate the transient electromagnetic field in radial two-layer models without wall rock and convert the simulation results to apparent resistivity using the all-time algorithm. The time-varying apparent resistivity reflects the radially layered geoelectrical structure of the models and the apparent resistivity of the earliest time channel follows the true resistivity of the inner layer; however, the apparent resistivity at larger times reflects the comprehensive electrical characteristics of the inner and outer layers. To accurately identify the outer layer resistivity based on the series relationship model of the layered resistance, the apparent resistivity and diffusion depth of the different time channels are approximately replaced by related model parameters; that is, we propose an apparent resistivity correction algorithm. By correcting the time-varying apparent resistivity of radial two-layer models, we show that the correction results reflect the radially layered electrical structure and the corrected resistivities of the larger time channels follow the outer layer resistivity. The transient electromagnetic fields of radially layered models with wall rock are simulated to obtain the 2D time-varying profiles of the apparent resistivity and corrections. The results suggest that the time-varying apparent resistivity and correction results reflect the vertical and radial geoelectrical structures. For models with small wall-rock effect, the correction removes the effect of the low-resistance inner layer on the apparent resistivity of the larger time channels.
Effect of radial meniscal tear on in situ forces of meniscus and tibiofemoral relationship.
Tachibana, Yuta; Mae, Tatsuo; Fujie, Hiromichi; Shino, Konsei; Ohori, Tomoki; Yoshikawa, Hideki; Nakata, Ken
2017-02-01
To clarify the effect of the radial tear of the lateral meniscus on the in situ meniscus force and the tibiofemoral relationship under axial loads and valgus torques. Ten intact porcine knees were settled to a 6-degree of freedom robotic system, while the force and 3-dimensional path of the knees were recorded via Universal Force Sensor (UFS) during 3 cycles of 250-N axial load and 5-Nm valgus torque at 15°, 30°, 45°, and 60° of knee flexion. The same examination was performed on the following 3 meniscal states sequentially; 33, 66, and 100% width of radial tears at the middle segment of the lateral meniscus, while recording the force and path of the knees via UFS. Finally, all paths were reproduced after total lateral meniscectomy and the in situ force of the lateral meniscus were calculated with the principle of superposition. The radial tear of 100% width significantly decreased the in situ force of the lateral meniscus and caused tibial medial shift and valgus rotation at 30°-60° of knee flexion in both testing protocols. Under a 250-N axial load at 60° of knee flexion, the in situ force decreased to 36 ± 29 N with 100% width of radial tear, which was 122 ± 38 N in the intact state. Additionally, the tibia shifted medially by 2.1 ± 0.9 mm and valgusrotated by 2.5 ± 1.9° with the complete radial tear. However, the radial tear of 33 or 66% width had little effect on either the in situ force or the tibial position. A radial tear of 100% width involving the rim significantly decreased the in situ force of the lateral meniscus and caused medial shift and valgus rotation of the tibia, whereas a radial tear of up to 66% width produced only little change. The clinical relevance is that loss of meniscal functions due to complete radial tear can lead to abnormal stress concentration in a focal area of cartilage and can increase the risk of osteoarthritis in the future.
Ray transference of a system with radial gradi- ent index
Directory of Open Access Journals (Sweden)
W. F. Harris
2012-12-01
Full Text Available The ray transference is central to the understanding of the first-order optical character of an optical system including the visual optical system of the eye. It can be calculated for dioptric and catadioptric systems from a knowledge of curvatures, tilts and spacing of surfaces in the system provided the material between successive surfaces has a uniform index of refraction. However the index of the natural lens of the eye is not uniform but varies with position. There is a need, therefore, for a method of calculating the transference of systems containing such gradient-index elements. As a first step this paper shows that the transference of elements in which the index varies radially can be obtained directly from published formulae. The transferences of radial-gradient systems are examined. Expressions are derived for several properties including the power, the front- and back-surface powers and the locations of the cardinal points. Equations are obtained for rays through such systems and for the locations of images of object points through them. Numerical examples are presented in the appen-dix. (S Afr Optom 2012 71(2 57-63
Matching problems in pulse power radial transmission lines
International Nuclear Information System (INIS)
Mittag, K.; Brandelik, A.
1984-12-01
In this report we study the power transfer from a generator along a coaxial transmission line followed by a radial transmission line into a load, which in our application is a pseudo-spark plasma of about one millimeter diameter and about 15 cm in length. First the theoretical background based on transmission line theory is described. Then numerical results are presented. The main conclusion is that when matching the pulse power generator to the pseudo-spark plasma, the effect of the impedance transformation caused by the radial transmission line has to be taken into account. The conditions to obtain an optimal match are described. (orig.) [de
Thermal load non-uniformity estimation for superheater tube bundle damage evaluation
Directory of Open Access Journals (Sweden)
Naď Martin
2018-01-01
Full Text Available Industrial boiler damage is a common phenomenon encountered in boiler operation which usually lasts several decades. Since boiler shutdown may be required because of localized failures, it is crucial to predict the most vulnerable parts. If damage occurs, it is necessary to perform root cause analysis and devise corrective measures (repairs, design modifications, etc.. Boiler tube bundles, such as those in superheaters, preheaters and reheaters, are the most exposed and often the most damaged boiler parts. Both short-term and long-term overheating are common causes of tube failures. In these cases, the design temperatures are exceeded, which often results in decrease of remaining creep life. Advanced models for damage evaluation require temperature history, which is available only in rare cases when it has been measured and recorded for the whole service life. However, in most cases it is necessary to estimate the temperature history from available operation history data (inlet and outlet pressures and temperatures etc.. The task may be very challenging because of the combination of complex flow behaviour in the flue gas domain and heat transfer phenomena. This paper focuses on estimating thermal load non-uniformity on superheater tubes via Computational Fluid Dynamics (CFD simulation of flue gas flow including heat transfer within the domain consisting of a furnace and a part of the first stage of the boiler.
Directory of Open Access Journals (Sweden)
Paulo E. S. Martins
2012-01-01
Full Text Available Neste trabalho o objetivo foi avaliar o perfil radial e a uniformidade de distribuição de água do aspersor fabricado pela empresa NaanDanJain, modelo 427 1/2"M e bocal de 2,8 mm de diâmetro interno, operando com pressões de 150, 200, 300 e 400 kPa em cinco posições do defletor de ajuste (0, 20, 50, 80 e 100%. Para a determinação dos parâmetros avaliados utilizou-se o método da malha e, com o auxílio do aplicativo computacional CATCH 3D, calculou-se a sobreposição das lâminas de água com dez espaçamentos. Os resultados obtidos demonstram que o defletor de ajuste influencia o raio de molhamento e o perfil de distribuição enquanto a uniformidade de aplicação de água se mostrou como mecanismo importante, visto que permite comportamento diferenciado para o aspersor, garantindo ampla faixa de utilização do equipamento.The study aimed to evaluate the radial profile and the uniformity of water distribution of sprinkler manufactured by the company NaanDanJain, model 427 1/2"M and nozzle with 2.8 mm of internal diameter, operating at pressures of 150, 200, 300 and 400 kPa and five positions of the deflector (0, 20, 50, 80 and 100%. For the determination of the parameters evaluated, the grid method was used and with the help of computer application CATCH 3D, overlapping layers of water depths was calculated with ten spacing. The results show that the deflector adjustment influences the radius of wetness and the distribution profile while the uniformity of water application showed as an important mechanism, since it permits different behavior for the sprinkler, ensuring wide track of utilization of the equipment.
Orbits of two electrons released from rest in a uniform transverse magnetic field
Mungan, Carl E.
2018-03-01
Two identical charged particles released from rest repel each other radially. A uniform perpendicular magnetic field will then cause their trajectories to curve into a flower petal pattern. The orbit of each particle is approximately circular with a long period for a strong magnetic field, whereas it becomes a figure-eight for a weak magnetic field with each lobe completed in a cyclotron period. For example, such radially bound motions arise for two-dimensional electron gases. The level of treatment is appropriate for an undergraduate calculus-based electromagnetism course.
Characterization of the loss allocation techniques for radial systems with distributed generation
International Nuclear Information System (INIS)
Carpaneto, Enrico; Chicco, Gianfranco; Sumaili Akilimali, Jean
2008-01-01
In the restructured electricity industry, meaningful loss allocation methods are required in order to send correct signals to the market taking into account the location and characteristics of loads and generations, including the local sources forming the distributed generation (DG). This paper addresses the issues related to loss allocation in radial distribution systems with DG, with a three-fold focus. First, the key differences in the formulation of the loss allocation problem for radial distribution systems with respect to transmission systems are discussed, specifying the modeling and computational issues concerning the treatment of the slack node in radial distribution systems. Then, the characteristics of derivative-based and circuit-based loss allocation techniques are presented and compared, illustrating the arrangements used for adapting the various techniques to be applied to radial distribution systems with DG. Finally, the effects of introducing voltage-controllable local generation on the calculation of the loss allocation coefficients are discussed, proposing the adoption of a ''reduced'' representation of the system capable of taking into proper account the characteristics of the nodes containing voltage-controllable DG units. Numerical results are provided to show the time evolution of the loss allocation coefficients for distribution systems with variable load and local generation patterns. (author)
Higher‐order mode absorption measurement of X-band choke-mode cavities in a radial line structure
International Nuclear Information System (INIS)
Zha, Hao; Shi, Jiaru; Wu, Xiaowei; Chen, Huaibi
2016-01-01
An experiment is presented to study the higher-order mode (HOM) suppression of X-band choke-mode structures with a vector network analyzer (VNA). Specific radial line disks were built to test the reflection from the corresponding damping load and different choke geometries. The mismatch between the radial lines and the VNA was calibrated through a special multi-short-load calibration method. The measured reflections of different choke geometries showed good agreement with the theoretical calculations and verified the HOM absorption feature of each geometric design.
Higher‐order mode absorption measurement of X-band choke-mode cavities in a radial line structure
Energy Technology Data Exchange (ETDEWEB)
Zha, Hao [Department of Engineering Physics, Tsinghua University, Beijing CN-100086 (China); Key Laboratory of Particle and Radiation Imaging, Tsinghua University, Ministry of Education, Beijing (China); The European Organization for Nuclear Research, Geneva CH-1211 (Switzerland); Shi, Jiaru, E-mail: shij@mail.tsinghua.edu.cn [Department of Engineering Physics, Tsinghua University, Beijing CN-100086 (China); Key Laboratory of Particle and Radiation Imaging, Tsinghua University, Ministry of Education, Beijing (China); The European Organization for Nuclear Research, Geneva CH-1211 (Switzerland); Wu, Xiaowei; Chen, Huaibi [Department of Engineering Physics, Tsinghua University, Beijing CN-100086 (China); Key Laboratory of Particle and Radiation Imaging, Tsinghua University, Ministry of Education, Beijing (China)
2016-04-01
An experiment is presented to study the higher-order mode (HOM) suppression of X-band choke-mode structures with a vector network analyzer (VNA). Specific radial line disks were built to test the reflection from the corresponding damping load and different choke geometries. The mismatch between the radial lines and the VNA was calibrated through a special multi-short-load calibration method. The measured reflections of different choke geometries showed good agreement with the theoretical calculations and verified the HOM absorption feature of each geometric design.
Magneto-acoustic resonance in a non-uniform current carrying plasma column
Vaclavik, J.
2017-01-01
The forced radial magneto-acoustic oscillations in a plasma column with nonuniform mass density and temperature are investigated. It turns out that the oscillations have a resonant character similar to that of the magneto-acoustic oscillations in a uniform plasma column. The properties of the axial and azimuthal components of the oscillating magnetic field are discussed in detail
International Nuclear Information System (INIS)
Tsakadze, E.L.; Ostrikov, K.; Tsakadze, Z.L.; Vladimirov, S.V.; Xu, S.
2004-01-01
Radial and axial distributions of magnetic fields in a low-frequency (∼460 kHz) inductively coupled plasma source with two internal crossed planar rf current sheets are reported. The internal antenna configuration comprises two orthogonal sets of eight alternately reconnected parallel and equidistant copper litz wires in quartz enclosures and generates three magnetic (H z , H r , and H φ ) and two electric (E φ and E r ) field components at the fundamental frequency. The measurements have been performed in rarefied and dense plasmas generated in the electrostatic (E) and electromagnetic (H) discharge modes using two miniature magnetic probes. It is shown that the radial uniformity and depth of the rf power deposition can be improved as compared with conventional sources of inductively coupled plasmas with external flat spiral ('pancake') antennas. Relatively deeper rf power deposition in the plasma source results in more uniform profiles of the optical emission intensity, which indicates on the improvement of the plasma uniformity over large chamber volumes. The results of the numerical modeling of the radial magnetic field profiles are found in a reasonable agreement with the experimental data
Directory of Open Access Journals (Sweden)
Tamilselvan V.
2016-06-01
Full Text Available The radial distribution system is a rugged system, it is also the most commonly used system, which suffers by loss and low voltage at the end bus. This loss can be reduced by the use of a capacitor in the system, which injects reactive current and also improves the voltage magnitude in the buses. The real power loss in the distribution line is the I2R loss which depends on the current and resistance. The connection of the capacitor in the bus reduces the reactive current and losses. The loss reduction is equal to the increase in generation, necessary for the electric power provided by firms. For consumers, the quality of power supply depends on the voltage magnitude level, which is also considered and hence the objective of the problem becomes the multi objective of loss minimization and the minimization of voltage deviation. In this paper, the optimal location and size of the capacitor is found using a new computational intelligent algorithm called Flower Pollination Algorithm (FPA. To calculate the power flow and losses in the system, novel data structure load flow is introduced. In this, each bus is considered as a node with bus associated data. Links between the nodes are distribution lines and their own resistance and reactance. To validate the developed FPA solutions standard test cases, IEEE 33 and IEEE 69 radial distribution systems are considered.
Internal loading of an inhomogeneous compressible Earth with phase boundaries
Defraigne, P.; Dehant, V.; Wahr, J. M.
1996-01-01
The geoid and the boundary topography caused by mass loads inside the earth were estimated. It is shown that the estimates are affected by compressibility, by a radially varying density distribution, and by the presence of phase boundaries with density discontinuities. The geoid predicted in the chemical boundary case is 30 to 40 percent smaller than that predicted in the phase case. The effects of compressibility and radially varying density are likely to be small. The inner core-outer core topography for loading inside the mantle and for loading inside the inner core were computed.
Generating higher-order radial Laguerre-Gaussian modes using a digital laser
CSIR Research Space (South Africa)
Bell, Teboho
2015-07-01
Full Text Available Using the digital laser one can generate various types of modes, like, Laguerre-Gaussian modes. The digital laser was forced to generate high-order radial Laguerre-Gaussian modes, LGp , with zero azimuthal order, by loading a digital hologram...
Applying controlled non-uniform deformation for in vitro studies of cell mechanobiology.
Balestrini, Jenna L; Skorinko, Jeremy K; Hera, Adriana; Gaudette, Glenn R; Billiar, Kristen L
2010-06-01
Cells within connective tissues routinely experience a wide range of non-uniform mechanical loads that regulate many cell behaviors. In this study, we developed an experimental system to produce complex strain patterns for the study of strain magnitude, anisotropy, and gradient effects on cells in culture. A standard equibiaxial cell stretching system was modified by affixing glass coverslips (5, 10, or 15 mm diameter) to the center of 35 mm diameter flexible-bottomed culture wells. Ring inserts were utilized to limit applied strain to different levels in each individual well at a given vacuum pressure thus enabling parallel experiments at different strain levels. Deformation fields were measured using high-density mapping for up to 6% applied strain. The addition of the rigid inclusion creates strong circumferential and radial strain gradients, with a continuous range of stretch anisotropy ranging from strip biaxial to equibiaxial strain and radial strains up to 24% near the inclusion. Dermal fibroblasts seeded within our 2D system (5 mm inclusions; 2% applied strain for 2 days at 0.2 Hz) demonstrated the characteristic orientation perpendicular to the direction of principal strain. Dermal fibroblasts seeded within fibrin gels (5 mm inclusions; 6% applied strain for 8 days at 0.2 Hz) oriented themselves similarly and compacted their surrounding matrix to an increasing extent with local strain magnitude. This study verifies how inhomogeneous strain fields can be produced in a tunable and simply constructed system and demonstrates the potential utility for studying gradients with a continuous spectrum of strain magnitudes and anisotropies.
Non-axial-symmetric Alfven waves in cylindrical, radial inhomogeneous plasmas
International Nuclear Information System (INIS)
Raeuchle, E.
1978-08-01
The propagation of nonaxialsymmetric Alfven waves is investigated theoretically. Eigenfunctions and dispersion relations are calculated numerically for radial inhomogeneous cylindrical plasmas. In the MHD treatment resistivity, neutral particle loading and ion cyclotron effects are included. The investigations are of importance for plasma heating by Alfven waves. (orig.) [de
Energy Technology Data Exchange (ETDEWEB)
Canobbio, E [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires. Services de Physique Appliquee, Service d' Ionique Generale, Section d' Etudes des Interactions Ondes Plasmas; Finzi, U [Institut de Physique Theorique de Milan (Italy)
1966-07-01
The motion of a charged particle in an axial uniform steady magnetic field, under the action of a radial space charge is calculated. A cylindrical symmetric charge distribution similar to the one which is observed in HF plasma accelerators is assumed. The particle motion is discussed with the method of effective potentials. A radial acceleration of ions is shown to be possible if the space charge density is sufficiently high. The displacement of the turning points of the trajectories due to the electrostatic field is calculated in the low plasma density approximation. Finally a HF circularly polarized electric field is introduced, the shift in cyclotron resonance is calculated and a low frequency resonance is found to be possible. (authors) [French] On etudie le mouvement d'une particule dans un champ magnetique axial uniforme et constant en presence d'un champ de charge d'espace radial. On considere une distribution de charge a symetrie cylindrique, semblable a celle qu'on observe dans les accelerateurs de plasma a H.F. On se sert des potentiels effectifs pour discuter les caracteristiques du mouvement. Une acceleration radiale des ions est possible lorsque la densite de charge est assez elevee. On calcule aussi les deplacements des points de rebroussement des trajectoires produits par un champ electrostatique faible. On introduit enfin un champ electrique HF polarise circulairement et on calcule le deplacement de la resonance de cyclotron du au champ de charge d'espace. En meme temps on voit apparaitre dans l'energie cinetique de la particule une resonance a basse frequence. (auteurs)
Radial force on the vacuum chamber wall during thermal quench in tokamaks
Energy Technology Data Exchange (ETDEWEB)
Pustovitov, V. D., E-mail: pustovitov-vd@nrcki.ru [National Research Centre Kurchatov Institute (Russian Federation)
2015-12-15
The radial force balance during a thermal quench in tokamaks is analyzed. As a rule, the duration τ{sub tp} of such events is much shorter than the resistive time τ{sub w} of the vacuum chamber wall. Therefore, the perturbations of the magnetic field B produced by the evolving plasma cannot penetrate the wall, which makes different the magnetic pressures on its inner and outer sides. The goal of this work is the analytical estimation of the resulting integral radial force on the wall. The plasma is considered axially symmetric; for the description of radial forces on the wall, the results of V.D. Shafranov’s classical work [J. Nucl. Energy C 5, 251 (1963)] are used. Developed for tokamaks, the standard equilibrium theory considers three interacting systems: plasma, poloidal field coils, and toroidal field coils. Here, the wall is additionally incorporated with currents driven by ∂B/∂t≠0 accompanying the fast loss of the plasma thermal energy. It is shown that they essentially affect the force redistribution, thereby leading to large loads on the wall. The estimates prove that these loads have to be accounted for in the disruptive scenarios in large tokamaks.
Scheres, B.J.G.; Di Laurenzio, L.; Willemsen, V.; Hauser, M.-T.; Janmaat, K.; Benfey, P.N.
1995-01-01
The primary root of Arabidopsis thaliana has a remarkably uniform cellular organisation. The fixed radial pattern of cell types in the mature root arises from proliferative divisions within the root meristem. The root meristem, in turn, is laid down during embryogenesis. We have analysed six
Porous stainless steel hollow fibers with shrinkage-controlled small radial dimensions
Luiten-Olieman, Maria W.J.; Raaijmakers, Michiel; Raaijmakers, Michiel J.T.; Winnubst, Aloysius J.A.; Wessling, Matthias; Nijmeijer, Arian; Benes, Nieck Edwin
2011-01-01
A method is presented for the preparation of thin (∼250 μm) porous stainless steel hollow fiber membranes based on dry–wet spinning of a particle-loaded polymer solution followed by heat treatment. Extraordinarily small radial dimensions were achieved by controlled shrinkage during thermal
Directory of Open Access Journals (Sweden)
Yonghui Xie
2014-01-01
Full Text Available A three-dimensional fluid-thermal-structural coupled analysis for a radial inflow micro gas turbine is conducted. First, a fluid-thermal coupled analysis of the flow and temperature fields of the nozzle passage and the blade passage is performed by using computational fluid dynamics (CFD. The flow and heat transfer characteristics of different sections are analyzed in detail. The thermal load and the aerodynamic load are then obtained from the temperature field and the pressure distribution. The stress distributions of the blade are finally studied by using computational solid mechanics (CSM considering three cases of loads: thermal load, aerodynamics load combined with centrifugal load, and all the three types of loads. The detailed parameters of the flow, temperature, and the stress are obtained and analyzed. The numerical results obtained provide a useful knowledge base for further exploration of radial gas turbine design.
Shaft centre orbit for dynamically loaded radial bearings
DEFF Research Database (Denmark)
Klit, Peder; Vølund, Anders
2002-01-01
The aim of this work is to demonstrate how to utilize the bearings damping coefficients to estimate the orbit for a dynamically loaded journal bearing. The classical method for this analysis was developed by Booker in 1965 Booker1 and described further in 1972 Booker2. Several authors have refine...
Yin, Yujian; Su, Ping; Ma, Jianshe
2018-01-01
A method to improve the radial resolution using special structured light is proposed in the field of digital holographic microscopy (DHM). A specimen is illuminated with circular symmetrical structured light that makes the spectrum have radial movement, so that high frequency components of the specimen are moved into the passband of the receiver to overcome the diffraction limit. In the DHM imaging system, Computer Generated Hologram (CGH) technology is used to generate the required structured light grating. Then the grating is loaded into a spatial light modulator (SLM) to obtain specific structured illumination. After recording the hologram, digital reconstruction, for the microstructure of a binary optical element that needs to observe radial distribution, the radial resolution of the specimen is improved experimentally compare it with the result of one-dimensional sinusoidal structured light imaging. And a method of designing structured light is presented.
The effect of non-uniform fuel rod temperatures on effective resonance integrals
International Nuclear Information System (INIS)
Reichel, A.
1961-06-01
The effective resonance integral for heterogeneous lattices can be reduced to the effective resonance integral for an equivalent homogeneous system with a fairly well defined error depending on lump size and geometry. This report investigates the effect of a radial parabolic temperature variation in cylindrical lumps on the equivalent homogeneous effective resonance integral. Also determined is the equivalent uniform temperature to be taken in the usual formulae to allow for non-uniform fuel rod temperature. This effective temperature is found to be T eff. = T s + 4/9 (T c - T s ) where T s and T c are the surface and central temperatures of the lump. (author)
Directory of Open Access Journals (Sweden)
Qingfei Gao
2015-01-01
Full Text Available To address the drawback of traditional method of investigating dynamic responses of the continuous girder bridge with uniform cross-section under moving vehicular loads, the orthogonal experimental design method is proposed in this paper. Firstly, some empirical formulas of natural frequencies are obtained by theoretical derivation and numerical simulation. The effects of different parameters on dynamic responses of the vehicle-bridge coupled vibration system are discussed using our own program. Finally, the orthogonal experimental design method is proposed for the dynamic responses analysis. The results show that the effects of factors on dynamic responses are dependent on both the selected position and the type of the responses. In addition, the interaction effects between different factors cannot be ignored. To efficiently reduce experimental runs, the conventional orthogonal design is divided into two phases. It has been proved that the proposed method of the orthogonal experimental design greatly reduces calculation cost, and it is efficient and rational enough to study multifactor problems. Furthermore, it provides a good way to obtain more rational empirical formulas of the DLA and other dynamic responses, which may be adopted in the codes of design and evaluation.
Probabilistic uniformities of uniform spaces
Energy Technology Data Exchange (ETDEWEB)
Rodriguez Lopez, J.; Romaguera, S.; Sanchis, M.
2017-07-01
The theory of metric spaces in the fuzzy context has shown to be an interesting area of study not only from a theoretical point of view but also for its applications. Nevertheless, it is usual to consider these spaces as classical topological or uniform spaces and there are not too many results about constructing fuzzy topological structures starting from a fuzzy metric. Maybe, H/{sup o}hle was the first to show how to construct a probabilistic uniformity and a Lowen uniformity from a probabilistic pseudometric /cite{Hohle78,Hohle82a}. His method can be directly translated to the context of fuzzy metrics and allows to characterize the categories of probabilistic uniform spaces or Lowen uniform spaces by means of certain families of fuzzy pseudometrics /cite{RL}. On the other hand, other different fuzzy uniformities can be constructed in a fuzzy metric space: a Hutton $[0,1]$-quasi-uniformity /cite{GGPV06}; a fuzzifiying uniformity /cite{YueShi10}, etc. The paper /cite{GGRLRo} gives a study of several methods of endowing a fuzzy pseudometric space with a probabilistic uniformity and a Hutton $[0,1]$-quasi-uniformity. In 2010, J. Guti/'errez Garc/'{/i}a, S. Romaguera and M. Sanchis /cite{GGRoSanchis10} proved that the category of uniform spaces is isomorphic to a category formed by sets endowed with a fuzzy uniform structure, i. e. a family of fuzzy pseudometrics satisfying certain conditions. We will show here that, by means of this isomorphism, we can obtain several methods to endow a uniform space with a probabilistic uniformity. Furthermore, these constructions allow to obtain a factorization of some functors introduced in /cite{GGRoSanchis10}. (Author)
Neuropathy - radial nerve; Radial nerve palsy; Mononeuropathy ... Damage to one nerve group, such as the radial nerve, is called mononeuropathy . Mononeuropathy means there is damage to a single nerve. Both ...
Akahoshi, Hikaru; Takahashi, Kazunori; Ando, Akira
2018-03-01
High temperature electrons generated near a radial wall of a cylindrical source tube in a radiofrequency (rf) inductively-coupled plasma is filtered by an axisymmetric radial magnetic field formed near the source exit by locating annular permanent magnets, where the axial magnetic field strength in the radially central region is fairly uniform inside the source tube and is close to zero near the source exit. The source is operated at 3 mTorr in argon and the rf antenna is powered by a 13.56 MHz and 400 W rf generator. Measurement of electron energy probability functions shows the presence of the peripheral high temperature electrons inside the source, while the temperature of the peripheral electrons downstream of the source is observed to be reduced.
Analysis of A Uniform Bernoulli – Euler Beam on Winkler Foundation ...
African Journals Online (AJOL)
ADOWIE PERE
2018-03-09
Mar 9, 2018 ... method to analyze Winkler foundation subjected to a harmonic moving load on a uniform Bernoulli – Euler Beam. MATLAB software was used to implement the Newmark time integration method to ... A lot of engineering structures under moving loads .... Because numerical procedure produce stability issue,.
Chai, Bo; Xu, Mengqiu; Yan, Juntao; Ren, Zhandong
2018-02-01
The MoS2/CdS composites with layered MoS2 loaded on uniform CdS nanospheres were synthesized by a two-step process combination hydrothermal and solvothermal treatments, and then applied in photocatalytic hydrogen evolution under visible light irradiation. The as-prepared samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectrometer (EDS), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), Raman spectra, UV-vis diffuse reflectance absorption spectra (UV-DRS), nitrogen adsorption-desorption measurement, photoluminescence spectra (PL) and photoelectrochemical tests. The effects of loading contents of MoS2 in the composites on the photocatalytic H2 evolution activity were comparatively investigated with 0.45 mol L-1 Na2S and 0.55 mol L-1 Na2SO3 as sacrificial agents. The results showed that the 5 wt% MoS2/CdS composite could achieve the highest photocatalytic H2 evolution rate of 372 μmol h-1 and apparent quantum efficiency (AQE) about 7.31% under 420 nm monochromatic light irradiation. The remarkably enhanced photocatalytic activity of MoS2/CdS composite could be attributed to the effective transfer and separation of photogenerated charge carriers, and MoS2 being as a cocatalyst to facilitating photocatalytic H2 evolution reaction. A tentative mechanism of MoS2/CdS composites as photocatalysts for H2 evolution was proposed.
Loading Deformation Characteristic Simulation Study of Engineering Vehicle Refurbished Tire
Qiang, Wang; Xiaojie, Qi; Zhao, Yang; Yunlong, Wang; Guotian, Wang; Degang, Lv
2018-05-01
The paper constructed engineering vehicle refurbished tire computer geometry model, mechanics model, contact model, finite element analysis model, did simulation study on load-deformation property of engineering vehicle refurbished tire by comparing with that of the new and the same type tire, got load-deformation of engineering vehicle refurbished tire under the working condition of static state and ground contact. The analysis result shows that change rules of radial-direction deformation and side-direction deformation of engineering vehicle refurbished tire are close to that of the new tire, radial-direction and side-direction deformation value is a little less than that of the new tire. When air inflation pressure was certain, radial-direction deformation linear rule of engineer vehicle refurbished tire would increase with load adding, however, side-direction deformation showed linear change rule, when air inflation pressure was low; and it would show increase of non-linear change rule, when air inflation pressure was very high.
Neu, C P; Hull, M L
2003-04-01
Recent magnetic resonance imaging (MRI) techniques have shown potential for measuring non-uniform deformations throughout the volume (i.e. three-dimensional (3D) deformations) in small orthopedic tissues such as articular cartilage. However, to analyze cartilage deformation using MRI techniques, a system is required which can construct images from multiple acquisitions of MRI signals from the cartilage in both the underformed and deformed states. The objectives of the work reported in this article were to 1) design an apparatus that could apply highly repeatable cyclic compressive loads of 400 N and operate in the bore of an MRI scanner, 2) demonstrate that the apparatus and MRI scanner can be successfully integrated to observe 3D deformations in a phantom material, 3) use the apparatus to determine the load cycle necessary to achieve a steady-state deformation response in normal bovine articular cartilage samples using a flat-surfaced and nonporous indentor in unconfined compression. Composed of electronic and pneumatic components, the apparatus regulated pressure to a double-acting pneumatic cylinder so that (1) load-controlled compression cycles were applied to cartilage samples immersed in a saline bath, (2) loading and recovery periods within a cycle varied in time duration, and (3) load magnitude varied so that the stress applied to cartilage samples was within typical physiological ranges. In addition the apparatus allowed gating for MR image acquisition, and operation within the bore of an MRI scanner without creating image artifacts. The apparatus demonstrated high repeatability in load application with a standard deviation of 1.8% of the mean 400 N load applied. When the apparatus was integrated with an MRI scanner programmed with appropriate pulse sequences, images of a phantom material in both the underformed and deformed states were constructed by assembling data acquired through multiple signal acquisitions. Additionally, the number of cycles to reach
Calculation of hydrostatic radial bearing for main circulating pump of 500 BIKS type
International Nuclear Information System (INIS)
Hnatek, T.; Sojka, P.
1978-01-01
Computer calculations of the radial hydrostatic bearing were performed for the main circulating pump of the 500 BIKS type designed for WWER reactors. The calculations were based on the Reynolds equation of thin layer hydrodynamic pressure in turbulent flow. Relations were derived for orifice reducer flow. In contrast to previous calculations conducted for laminar flow, the results are more accurate because the nature of bearing lubrication evidently is turbulent. The required loading of 21,700 N in normal pump operation is fully compensated at a full eccentricity of 0.77. Operating tests of the pump also confirmed that the actual radial forces on the rotor did not attain the desired loading. On the other hand, thanks to the bearing brass design, the bearing is capable of short-time operation with limit eccentricity, ie., at start, in deceleration and in emergency conditions. (Z.M.)
Energy Technology Data Exchange (ETDEWEB)
Griffiths, S.K.; Nilson, R.H.
1996-06-01
A second-order perturbation solution describing the radial transport of a reactive species and concurrent deposition on wafer surfaces is derived for use in optimizing CVD process conditions. The result is applicable to a variety of deposition reactions and accounts for both diffusive and advective transport, as well as both ordinary and Knudsen diffusion. Based on the first-order approximation, the deposition rate is maximized subject to a constraint on the radial uniformity of the deposition rate. For a fixed reactant mole fraction, the optimum pressure and optimum temperature are obtained using the method of Lagrange multipliers. This yields a weak one-sided maximum; deposition rates fall as pressures are reduced but remain nearly constant at all pressures above the optimum value. The deposition rate is also maximized subject to dual constraints on the uniformity and particle nucleation rate. In this case, the optimum pressure, optimum temperature and optimum reactant fraction are similarly obtained, and the resulting maximum deposition rate is well defined. These results are also applicable to CVI processes used in composites manufacturing.
Energy Technology Data Exchange (ETDEWEB)
Fukuyama, H.; Takizawa, T. [NSK Ltd., Kanagawa (Japan)
1999-11-25
In the design of a large-scale flywheel. load capacity and bearing constants (i.e. spring and damping constants) should be accurately calculated. In this report, a newly developed analysis method for radial-type superconducting magnetic bearings (SMBs) composed of several couples of magnet rings and magnetic material spacers is described. The analysis based both on electromagnetic FEM of the magnetic field and the 2-dimensional Bean model for analysis of the magnetization of type-2 superconductors. To obtain accurate magnetization hysteresis that reflects the complex magnetic fields, a superconductor is meshed into cells and then the electromagnetic force between the magnetic fields of magnetics and the magnetization of the superconductor are calculated. Recently, computer programs which can calculate the axial load capacity of radial-type SMBs have been developed. Furthermore, programs which can calculate bearing constants are close to being completed. Calculated results on axial load capacity showed good agreement with the experimental results. (author)
Radial head button holing: a cause of irreducible anterior radial head dislocation
Energy Technology Data Exchange (ETDEWEB)
Shin, Su-Mi; Chai, Jee Won; You, Ja Yeon; Park, Jina [Seoul National University Seoul Metropolitan Government Boramae Medical Center, Department of Radiology, Seoul (Korea, Republic of); Bae, Kee Jeong [Seoul National University Seoul Metropolitan Government Boramae Medical Center, Department of Orthopedic Surgery, Seoul (Korea, Republic of)
2016-10-15
''Buttonholing'' of the radial head through the anterior joint capsule is a known cause of irreducible anterior radial head dislocation associated with Monteggia injuries in pediatric patients. To the best of our knowledge, no report has described an injury consisting of buttonholing of the radial head through the annular ligament and a simultaneous radial head fracture in an adolescent. In the present case, the radiographic findings were a radial head fracture with anterior dislocation and lack of the anterior fat pad sign. Magnetic resonance imaging (MRI) clearly demonstrated anterior dislocation of the fractured radial head through the torn annular ligament. The anterior joint capsule and proximal portion of the annular ligament were interposed between the radial head and capitellum, preventing closed reduction of the radial head. Familiarity with this condition and imaging findings will aid clinicians to make a proper diagnosis and fast decision to perform an open reduction. (orig.)
Three-Phase Unbalanced Load Flow Tool for Distribution Networks
DEFF Research Database (Denmark)
Demirok, Erhan; Kjær, Søren Bækhøj; Sera, Dezso
2012-01-01
This work develops a three-phase unbalanced load flow tool tailored for radial distribution networks based on Matlab®. The tool can be used to assess steady-state voltage variations, thermal limits of grid components and power losses in radial MV-LV networks with photovoltaic (PV) generators where...... most of the systems are single phase. New ancillary service such as static reactive power support by PV inverters can be also merged together with the load flow solution tool and thus, the impact of the various reactive power control strategies on the steady-state grid operation can be simply...... investigated. Performance of the load flow solution tool in the sense of resulting bus voltage magnitudes is compared and validated with IEEE 13-bus test feeder....
Stabe, Roy G.; Schwab, John R.
1991-01-01
A 0.767-scale model of a turbine stator designed for the core of a high-bypass-ratio aircraft engine was tested with uniform inlet conditions and with an inlet radial temperature profile simulating engine conditions. The principal measurements were radial and circumferential surveys of stator-exit total temperature, total pressure, and flow angle. The stator-exit flow field was also computed by using a three-dimensional Navier-Stokes solver. Other than temperature, there were no apparent differences in performance due to the inlet conditions. The computed results compared quite well with the experimental results.
Manipulation of viscous fingering in a radially tapered cell geometry
Bongrand, Grégoire; Tsai, Peichun Amy
2018-06-01
When a more mobile fluid displaces another immiscible one in a porous medium, viscous fingering propagates with a partial sweep, which hinders oil recovery and soil remedy. We experimentally investigate the feasibility of tuning such fingering propagation in a nonuniform narrow passage with a radial injection, which is widely used in various applications. We show that a radially converging cell can suppress the common viscous fingering observed in a uniform passage, and a full sweep of the displaced fluid is then achieved. The injection flow rate Q can be further exploited to manipulate the viscous fingering instability. For a fixed gap gradient α , our experimental results show a full sweep at a small Q but partial displacement with fingering at a sufficient Q . Finally, by varying α , we identify and characterize the variation of the critical threshold between stable and unstable displacements. Our experimental results reveal good agreement with theoretical predictions by a linear stability analysis.
Liquid jets injected into non-uniform crossflow
Tambe, Samir
An experimental study has been conducted with liquid jets injected transversely into a crossflow to study the effect of non-uniformities in the crossflow velocity distribution to the jet behavior. Two different non-uniform crossflows were created during this work, a shear-laden crossflow and a swirling crossflow. The shear-laden crossflow was generated by merging two independent, co-directional, parallel airstreams creating a shear mixing layer at the interface between them. The crossflow exhibited a quasi-linear velocity gradient across the height of the test chamber. By varying the velocities of the two airstreams, the sense and the slope of the crossflow velocity gradient could be changed. Particle Image Velocimetry (PIV) studies were conducted to characterize the crossflow. The parameter, UR, is defined as the ratio of the velocities of the two streams and governs the velocity gradient. A positive velocity gradient was observed for UR > 1 and a negative velocity gradient for UR Phase Doppler Particle Anemometry (PDPA) studies were conducted to study the penetration and atomization of 0.5 mm diameter water jets injected into this crossflow. The crossflow velocity gradient was observed to have a significant effect on jet penetration as well as the post breakup spray. For high UR (> 1), jet penetration increased and the Sauter Mean Diameter (SMD) distribution became more uniform. For low UR (Doppler Velocimetry (LDV) was used to study the crossflow velocities. The axial (Ux) and the tangential (Utheta) components of the crossflow velocity were observed to decrease with increasing radial distance away from the centerbody. The flow angle of the crossflow was smaller than the vane exit angle, with the difference increasing with the vane exit angle. Water jets were injected from a 0.5 mm diameter orifice located on a cylindrical centerbody. Multi-plane PIV measurements were conducted to study the penetration and droplet velocity distribution of the jets. The jets were
Directory of Open Access Journals (Sweden)
Hikaru Akahoshi
2018-03-01
Full Text Available High temperature electrons generated near a radial wall of a cylindrical source tube in a radiofrequency (rf inductively-coupled plasma is filtered by an axisymmetric radial magnetic field formed near the source exit by locating annular permanent magnets, where the axial magnetic field strength in the radially central region is fairly uniform inside the source tube and is close to zero near the source exit. The source is operated at 3 mTorr in argon and the rf antenna is powered by a 13.56 MHz and 400 W rf generator. Measurement of electron energy probability functions shows the presence of the peripheral high temperature electrons inside the source, while the temperature of the peripheral electrons downstream of the source is observed to be reduced.
An automated optimization of core fuel loading pattern for pressurized water reactors
International Nuclear Information System (INIS)
Chen Renji
1988-11-01
An optimum method was adopted to search for an optimum fuel loading pattern in pressurized water reactors. A radial power peak factor was chosen as the objective function of the optimum loading. The direct search method with shuffling rules is used to find optimum solution. The search for an optimum loading pattern with the smallest radial power peak by exchanging fuel assemblies was made. The search process is divided into two steps. In the first step fresh fuels or high reactivity fuels are arranged which are placed in core interior to have a reasonable fuel loading pattern. To further reduce the radial power peak factor, the second step will be necessary to rearrange the exposed lower reactivity fuel around the assemblies which has the radial power peak. In optimum process 1.5 group coarse mesh diffusion theory or two group nodal Green function diffusion theory is utilized to calculate the two dimensional power distribution after each shuffle. Also, above two methods are combinatively utilized to calculate the state quantity. It is not only true to save CPU time, but also can obtian exact results. Besides above function, the code MSOFEL is used to search critical boron concentration and to predict burn-up. The code has been written with FORTRAN-4. The optimum loading pattern was chosen for OCONEE and QINSHAN nuclear power plants as reference examples. The validity and feasibility of MSOFEL was demonstrated
Khine, Y. Y.; Walker, J. S.
1996-08-01
Centrifugal pumping flows are produced in the melt by the rotations of crystal and crucible during the Czochralski growth of silicon crystals. This paper treats the centrifugal pumping effects with a steady, strong, non-uniform axisymmetric magnetic field. We consider a family of magnetic fields ranging from a uniform axial field to a "cusp" field, which has a purely radial field at the crystal-melt interface and free surface. We present the numerical solutions for the centrifugal pumping flows as the magnetic field is changed continuously from a uniform axial field to a cusp one, and for arbitrary Hartmann number. Since the perfect alignment between the local magnetic field vector and the crystal-melt interface or free surface is not likely, we also investigate the effects of a slight misalignment.
International Nuclear Information System (INIS)
Li Ying; Qiu Xinming; Yin Yajun; Yang Fan; Fan Qinshan
2009-01-01
Under hydrostatic pressure, the equivalent elastic moduli of a zigzag single-walled carbon nanotube (SWNT) are analytically determined by energy conservation, with the consideration of the covalent bond deformation. The theoretical predictions on the transverse mechanical properties of a zigzag SWNT agree reasonably well with those given by the molecular structures mechanics simulations and also the ab initio calculations. From the simple geometry calculation, the circumferential strain is about 2-3 times of the axial strain of a zigzag SWNT under hydrostatic pressure. The bulk modulus of a zigzag SWNT is found to be 3/7 times of its radial Young's modulus.
Stability of radial and non-radial pulsation modes of massive ZAMS models
International Nuclear Information System (INIS)
Odell, A.P.; Pausenwein, A.; Weiss, W.W.; Hajek, A.
1987-01-01
The authors have computed non-adiabatic eigenvalues for radial and non-radial pulsation modes of star models between 80 and 120 M solar with composition of chi=0.70 and Z=0.02. The radial fundamental mode is unstable in models with mass greater than 95 M solar , but the first overtone mode is always stable. The non-radial modes are all stable for all models, but the iota=2 f-mode is the closest to being driven. The non-radial modes are progressively more stable with higher iota and with higher n (for both rho- and g-modes). Thus, their results indicate that radial pulsation limits the upper mass of a star
Rotary and radial forcing effects on center-of-mass locomotion dynamics.
Shen, Z H; Larson, P L; Seipel, J E
2014-09-01
Rotary and radial forcing are two common actuation methods for legged robots. However, these two orthogonal methods of center-of-mass (CoM) forcing have not been compared as potentially alternative strategies of actuation. In this paper, we compare the CoM stability and energetics of running with rotary and radial actuation through the simulation of two models: the rotary-forced spring-loaded inverted pendulum (rotary-forced-SLIP), and the radially-forced-SLIP. We model both radial and rotary actuation in the simplest way, applying them as a constant force during the stance portion of the gait. A simple application of constant rotary forcing throughout stance is capable of producing fully-asymptotically stable motion; however, a similarly constant application of radial forcing throughout the stance is not capable of producing stable solutions. We then allow both the applied rotary and radial forcing functions to turn on or off based on the occurrence of the mid-stance event, which breaks the symmetry of actuation during stance towards a net forward propulsion. We find that both a rotary force applied in the first half of stance and a radial force applied in the second half of stance, are capable of stabilizing running. Interestingly, these two forcing methods improve the motion stability in different ways. Rotary forcing first reduces then greatly increases the size of the stable parameter region when gradually increased. Radial forcing expands the stable parameter region, but only in a moderate way. Also, it is found that parameter region stabilized by rotary and radial forcing are largely complementary. Overall, rotary forcing can better stabilize running for both constant and event-based forcing functions that were attempted. This indicates that rotary forcing has an inherent capability of stabilizing running, even when minimal time-or-event-or-state feedback is present. Radial forcing, however, tends to be more energy efficient when compared to rotary forcing
Leveraging Non-Uniform Resources for Parallel Query Processing
DEFF Research Database (Denmark)
Mayr, Tobias; Bonnet, Philippe; Gehrke, Johannes
2003-01-01
Modular clusters are now composed of non- uniform nodes with different CPUs, disks or network cards so that customers can adapt the cluster configuration to the changing technologies and to their changing needs. This challenges dataflow parallelism as the primary load balancing technique of exist...
Some properties of a non-static uniform density sphere with center singularity
International Nuclear Information System (INIS)
Knutsen, H.
1984-01-01
A class of exact models for non-static uniform density spheres with pressure gradient and singularity is investigated. Necessary and sufficient conditions are given for the pressure gradient to be negative and for the circumference of the sphere to be an increasing function of radial coordinate. The time history of marginally trapped surfaces are studied, and it is found that for physically acceptable models the singularity is always hidden by a trapped surface. (Auth.)
Kewel, M.; Renner, J.
2017-12-01
The variation of hydraulic properties during sliding events is of importance for source mechanics and analyses of the evolution in effective stresses. We conducted laboratory experiments on samples of Padang granite to elucidate the interrelation between shear displacement on faults and their hydraulic properties. The cylindrical samples of 30 mm diameter and 75 mm length were prepared with a ground sawcut, inclined 35° to the cylindrical axis and accessed by a central bore of 3 mm diameter. The conventional triaxial compression experiments were conducted at effective pressures of 30, 50, and 70 MPa at slip rates of 2×10-4 and 8×10-4 mm s-1. The nominally constant fluid pressure of 30 MPa was modulated by oscillations with an amplitude of up to 0.5 MPa. Permeability and specific storage capacity of the fault were determined using the oscillatory radial-flow method that rests on an analysis of amplitude ratio and phase shift between the oscillatory fluid pressure and the oscillatory fluid flow from and into the fault plane. This method allowed us to continuously monitor the hydraulic evolution during elastic loading and frictional sliding. The chosen oscillation period of 60 s guaranteed a resolution of hydraulic properties for slip increments as small as 20 μm. The determined hydraulic properties show a fairly uniform dependence on normal stress at hydrostatic conditions and initial elastic loading. The samples exhibited stable frictional sliding with modest strengthening with increasing strain. Since not all phase-shift values fell inside the theoretical range for purely radial pressure diffusion during frictional sliding, the records of equivalent hydraulic properties exhibit some gaps. In the phases with evaluable phase-shift values, permeability fluctuates by almost one order of magnitude over slip intervals of as little as 100 μm. We suppose that the observed fluctuations are related to comminution and reconfiguration of asperities on the fault planes
Comparing CTH simulations and experiments on explosively loaded rings
Braithwaite, C. H.; Aydelotte, Brady; Collins, Adam; Thadhani, Naresh; Williamson, David Martin
2012-03-01
A series of experiments were conducted on explosively loaded metallic rings for the purpose of studying fragmentation. In addition to the collection of fragments for analysis, the radial velocity of the expanding ring was measured with photon Doppler velocimetry (PDV) and the arrangement was imaged using high speed photography. Both the ring material and the material used as the explosive container were altered and the results compared with simulations performed in CTH. Good agreement was found between the simulations and the experiments. The maximum radial velocity attained was approximately 380 m/s, which was achieved through loading with a 5g PETN based charge.
Effect of bed configuration on pebble flow uniformity and stagnation in the pebble bed reactor
International Nuclear Information System (INIS)
Gui, Nan; Yang, Xingtuan; Tu, Jiyuan; Jiang, Shengyao
2014-01-01
Highlights: • Pebble flow uniformity and stagnation characteristics are very important for HTR-PM. • Arc- and brachistochrone-shaped configuration effects are studied by DEM simulation. • Best bed configurations with uniform flow and no stagnated pebbles are suggested. • Detailed quantified characteristics of bed configuration effects are shown for explanation. - Abstract: Pebble flow uniformity and stagnation characteristics are very important for the design of pebble bed high temperature gas-cooled reactor. Pebble flows inside some specifically designed contraction configurations of pebble bed are studied by discrete element method. The results show the characteristics of stagnation rates, recycling rates, radial distribution of pebble velocity and residence time. It is demonstrated clearly that the bed with a brachistochrone-shaped configuration achieves optimum levels of flow uniformity and recycling rate concentration, and almost no pebbles are stagnated in the bed. Moreover, the optimum choice among the arc-shaped bed configurations is demonstrated too. Detailed information shows the quantified characteristics of bed configuration effects on flow uniformity. In addition, a good design of the pebble bed configuration is suggested
Bridge density functional approximation for non-uniform hard core repulsive Yukawa fluid
International Nuclear Information System (INIS)
Zhou Shiqi
2008-01-01
In this work, a bridge density functional approximation (BDFA) (J. Chem. Phys. 112, 8079 (2000)) for a non-uniform hard-sphere fluid is extended to a non-uniform hard-core repulsive Yukawa (HCRY) fluid. It is found that the choice of a bulk bridge functional approximation is crucial for both a uniform HCRY fluid and a non-uniform HCRY fluid. A new bridge functional approximation is proposed, which can accurately predict the radial distribution function of the bulk HCRY fluid. With the new bridge functional approximation and its associated bulk second order direct correlation function as input, the BDFA can be used to well calculate the density profile of the HCRY fluid subjected to the influence of varying external fields, and the theoretical predictions are in good agreement with the corresponding simulation data. The calculated results indicate that the present BDFA captures quantitatively the phenomena such as the coexistence of solid-like high density phase and low density gas phase, and the adsorption properties of the HCRY fluid, which qualitatively differ from those of the fluids combining both hard-core repulsion and an attractive tail. (condensed matter: structure, thermal and mechanical properties)
Rotary and radial forcing effects on center-of-mass locomotion dynamics
International Nuclear Information System (INIS)
Shen, Z H; Larson, P L; Seipel, J E
2014-01-01
Rotary and radial forcing are two common actuation methods for legged robots. However, these two orthogonal methods of center-of-mass (CoM) forcing have not been compared as potentially alternative strategies of actuation. In this paper, we compare the CoM stability and energetics of running with rotary and radial actuation through the simulation of two models: the rotary-forced spring-loaded inverted pendulum (rotary-forced-SLIP), and the radially-forced-SLIP. We model both radial and rotary actuation in the simplest way, applying them as a constant force during the stance portion of the gait. A simple application of constant rotary forcing throughout stance is capable of producing fully-asymptotically stable motion; however, a similarly constant application of radial forcing throughout the stance is not capable of producing stable solutions. We then allow both the applied rotary and radial forcing functions to turn on or off based on the occurrence of the mid-stance event, which breaks the symmetry of actuation during stance towards a net forward propulsion. We find that both a rotary force applied in the first half of stance and a radial force applied in the second half of stance, are capable of stabilizing running. Interestingly, these two forcing methods improve the motion stability in different ways. Rotary forcing first reduces then greatly increases the size of the stable parameter region when gradually increased. Radial forcing expands the stable parameter region, but only in a moderate way. Also, it is found that parameter region stabilized by rotary and radial forcing are largely complementary. Overall, rotary forcing can better stabilize running for both constant and event-based forcing functions that were attempted. This indicates that rotary forcing has an inherent capability of stabilizing running, even when minimal time-or-event-or-state feedback is present. Radial forcing, however, tends to be more energy efficient when compared to rotary forcing
Radial effects in heating and thermal stability of a sub-ignited tokamak
International Nuclear Information System (INIS)
Fuchs, V.; Shoucri, M.M.; Thibaudeau, G.; Harten, L.; Bers, A.
1982-02-01
The existence of thermally stable sub-ignited equilibria of a tokamak reactor, sustained in operation by a feedback-controlled supplementary heating source, is demonstrated. The establishment of stability depends on a number of radially non-uniform, nonlinear processes whose effect is analyzed. One-dimensional (radial) stability analyses of model transport equations, together with numerical results from a 1-D transport code, are used in studying the heating of DT-plasmas in the thermonuclear regime. Plasma core supplementary heating is found to be a thermally more stable process than bulk heating. In the presence of impurity line radiation, however, core-heated temperature profiles may collapse, contracting inward from the limiter, the result of an instability caused by the increasing nature of the radiative cooling rate, with decreasing temperature. Conditions are established for the realization of a sub-ignited high-Q, toroidal reactor plasma with appreciable output power
Computing closest saddle node bifurcations in a radial system via conic programming
Energy Technology Data Exchange (ETDEWEB)
Jabr, R.A. [Electrical, Computer and Communication Engineering Department, Notre Dame University, P.O. Box 72, Zouk Mikhael, Zouk Mosbeh (Lebanon); Pal, B.C. [Department of Electrical and Electronic Engineering, Imperial College London, SW7 2BT (United Kingdom)
2009-07-15
This paper considers the problem of computing the loading limits in a radial system which are (i) locally closest to current operating load powers and (ii) at which saddle node bifurcation occurs. The procedure is based on a known technique which requires iterating between two computational steps until convergence. In essence, step 1 produces a vector normal to the real and/or reactive load solution space boundary, whereas step 2 computes the bifurcation point along that vector. The paper shows that each of the above computational steps can be formulated as a second-order cone program for which polynomial time interior-point methods and efficient implementations exist. The proposed conic programming approach is used to compute the closest bifurcation points and the corresponding worst case load power margins of eleven different distribution systems. The approach is validated graphically and the existence of multiple load power margins is investigated. (author)
Root cortical aerenchyma inhibits radial nutrient transport in maize (Zea mays).
Hu, Bo; Henry, Amelia; Brown, Kathleen M; Lynch, Jonathan P
2014-01-01
Formation of root cortical aerenchyma (RCA) can be induced by nutrient deficiency. In species adapted to aerobic soil conditions, this response is adaptive by reducing root maintenance requirements, thereby permitting greater soil exploration. One trade-off of RCA formation may be reduced radial transport of nutrients due to reduction in living cortical tissue. To test this hypothesis, radial nutrient transport in intact roots of maize (Zea mays) was investigated in two radiolabelling experiments employing genotypes with contrasting RCA. In the first experiment, time-course dynamics of phosphate loading into the xylem were measured from excised nodal roots that varied in RCA formation. In the second experiment, uptake of phosphate, calcium and sulphate was measured in seminal roots of intact young plants in which variation in RCA was induced by treatments altering ethylene action or genetic differences. In each of three paired genotype comparisons, the rate of phosphate exudation of high-RCA genotypes was significantly less than that of low-RCA genotypes. In the second experiment, radial nutrient transport of phosphate and calcium was negatively correlated with the extent of RCA for some genotypes. The results support the hypothesis that RCA can reduce radial transport of some nutrients in some genotypes, which could be an important trade-off of this trait.
International Nuclear Information System (INIS)
Xia, Huanxiong; Xiang, Dong; Yang, Wang; Mou, Peng
2014-01-01
Low-temperature plasma technique is one of the critical techniques in IC manufacturing process, such as etching and thin-film deposition, and the uniformity greatly impacts the process quality, so the design for the plasma uniformity control is very important but difficult. It is hard to finely and flexibly regulate the spatial distribution of the plasma in the chamber via controlling the discharge parameters or modifying the structure in zero-dimensional space, and it just can adjust the overall level of the process factors. In the view of this problem, a segmented non-uniform dielectric module design solution is proposed for the regulation of the plasma profile in a CCP chamber. The solution achieves refined and flexible regulation of the plasma profile in the radial direction via configuring the relative permittivity and the width of each segment. In order to solve this design problem, a novel simulation-based auto-design approach is proposed, which can automatically design the positional sequence with multi independent variables to make the output target profile in the parameterized simulation model approximate the one that users preset. This approach employs an idea of quasi-closed-loop control system, and works in an iterative mode. It starts from initial values of the design variable sequences, and predicts better sequences via the feedback of the profile error between the output target profile and the expected one. It never stops until the profile error is narrowed in the preset tolerance
Modal Analysis of a Steel Radial Gate Exposed to Different Water Levels
Brusewicz, Krzysztof; Sterpejkowicz-Wersocki, Witold; Jankowski, Robert
2017-06-01
With the increase in water retention needs and planned river regulation, it might be important to investigate the dynamic resistance of vulnerable elements of hydroelectric power plants, including steelwater locks. The most frequent dynamic loads affecting hydroengineering structures in Poland include vibrations caused by heavy road and railway traffic, piling works and mining tremors. More destructive dynamic loads, including earthquakes, may also occur in our country, although their incidence is relatively low. However, given the unpredictable nature of such events, as well as serious consequences they might cause, the study of the seismic resistance of the steel water gate, as one of the most vulnerable elements of a hydroelectric power plant, seems to be important. In this study, a steel radial gate has been analyzed. As far as water gates are concerned, it is among the most popular solutions because of its relatively small weight, compared to plain gates. A modal analysis of the steel radial gate was conducted with the use of the FEM in the ABAQUS software. All structural members were modelled using shell elements with detailed geometry representing a real structure.Water was modelled as an added mass affecting the structure. Different water levels were used to determine the most vulnerable state of the working steel water gate. The results of the modal analysis allowed us to compare the frequencies and their eigenmodes in response to different loads, which is one of the first steps in researching the dynamic properties of steel water gates and their behaviour during extreme dynamic loads, including earthquakes.
Optimum Control for Nonlinear Dynamic Radial Deformation of Turbine Casing with Time-Varying LSSVM
Directory of Open Access Journals (Sweden)
Cheng-Wei Fei
2015-01-01
Full Text Available With the development of the high performance and high reliability of aeroengine, the blade-tip radial running clearance (BTRRC of high pressure turbine seriously influences the reliability and performance of aeroengine, wherein the radial deformation control of turbine casing has to be concerned in BTRRC design. To improve BTRRC design, the optimum control-based probabilistic optimization of turbine casing radial deformation was implemented using time-varying least square support vector machine (T-LSSVM by considering nonlinear material properties and dynamic thermal load. First the T-LSSVM method was proposed and its mathematical model was established. And then the nonlinear dynamic optimal control model of casing radial deformation was constructed with T-LSSVM. Thirdly, through the numerical experiments, the T-LSSVM method is demonstrated to be a promising approach in reducing additional design samples and improving computational efficiency with acceptable computational precision. Through the optimum control-based probabilistic optimization for nonlinear dynamic radial turbine casing deformation, the optimum radial deformation is 7.865 × 10−4 m with acceptable reliability degree 0.995 6, which is reduced by 7.86 × 10−5 m relative to that before optimization. These results validate the effectiveness and feasibility of the proposed T-LSSVM method, which provides a useful insight into casing radial deformation, BTRRC control, and the development of gas turbine with high performance and high reliability.
Dynamic behaviour of non-uniform Bernoulli-Euler beams subjected ...
African Journals Online (AJOL)
This paper investigates the dynamics behaviour of non-uniform Bernoulli-Euler beams subjected to concentrated loads ravelling at variable velocities. The solution technique is based on the Generalized Galerkin Method and the use of the generating function of the Bessel function type. The results show that, for all the ...
Petersen, Dick; Howard, Carl; Prime, Zebb
2015-02-01
This paper presents an analytical formulation of the load distribution and varying effective stiffness of a ball bearing assembly with a raceway defect of varying size, subjected to static loading in the radial, axial and rotational degrees of freedom. The analytical formulation is used to study the effect of the size of the defect on the load distribution and varying stiffness of the bearing assembly. The study considers a square-shaped outer raceway defect centered in the load zone and the bearing is loaded in the radial and axial directions while the moment loads are zero. Analysis of the load distributions shows that as the defect size increases, defect-free raceway sections are subjected to increased static loading when one or more balls completely or partly destress when positioned in the defect zone. The stiffness variations that occur when balls pass through the defect zone are significantly larger and change more rapidly at the defect entrance and exit than the stiffness variations that occur for the defect-free bearing case. These larger, more rapid stiffness variations generate parametric excitations which produce the low frequency defect entrance and exit events typically observed in the vibration response of a bearing with a square-shaped raceway defect. Analysis of the stiffness variations further shows that as the defect size increases, the mean radial stiffness decreases in the loaded radial and axial directions and increases in the unloaded radial direction. The effects of such stiffness changes on the low frequency entrance and exit events in the vibration response are simulated with a multi-body nonlinear dynamic model. Previous work used the time difference between the low frequency entrance event and the high frequency exit event to estimate the size of the defect. However, these previous defect size estimation techniques cannot distinguish between defects that differ in size by an integer number of the ball angular spacing, and a third feature
International Nuclear Information System (INIS)
Crebbin, K.C.
1985-05-01
Uniform magnetic field perturbations cause a closed orbit distortion in a circular accelerator. If the magnetic guide field is non-linear these perturbations can also cause a Nu shift in the betatron oscillations. Such a shift in radial Nu values has been observed in the Bevalac while studying the low energy resonant extraction system. In the Bevalac, the radial perturbation comes from the quadrants being magnetically about 0.8% longer than 90 0 . The normal effect of this type of perturbation is a radial closed orbit shift and orbit distortion. The Nu shift, associated with this type of perturbation in the presence of a non-linear guide field, is discussed in this paper. A method of handling the non-linear n values is discussed as well as the mechanism for the associated Nu shift. Computer calculations are compared to measurements. 2 refs., 4 figs
Heuristic for solving capacitor allocation problems in electric energy radial distribution networks
Directory of Open Access Journals (Sweden)
Maria A. Biagio
2012-04-01
Full Text Available The goal of the capacitor allocation problem in radial distribution networks is to minimize technical losses with consequential positive impacts on economic and environmental areas. The main objective is to define the size and location of the capacitors while considering load variations in a given horizon. The mathematical formulation for this planning problem is given by an integer nonlinear mathematical programming model that demands great computational effort to be solved. With the goal of solving this problem, this paper proposes a methodology that is composed of heuristics and Tabu Search procedures. The methodology presented explores network system characteristics of the network system reactive loads for identifying regions where procedures of local and intensive searches should be performed. A description of the proposed methodology and an analysis of computational results obtained which are based on several test systems including actual systems are presented. The solutions reached are as good as or better than those indicated by well referenced methodologies. The technique proposed is simple in its use and does not require calibrating an excessive amount of parameters, making it an attractive alternative for companies involved in the planning of radial distribution networks.
Directory of Open Access Journals (Sweden)
Jeom Kee Paik
2012-01-01
Full Text Available The Galerkin method is applied to analyze the elastic large deflection behavior of metal plates subject to a combination of in-plane loads such as biaxial loads, edge shear and biaxial inplane bending moments, and uniformly or nonuniformly distributed lateral pressure loads. The motive of the present study was initiated by the fact that metal plates of ships and ship-shaped offshore structures at sea are often subjected to non-uniformly distributed lateral pressure loads arising from cargo or water pressure, together with inplane axial loads or inplane bending moments, but the current practice of the maritime industry usually applies some simplified design methods assuming that the non-uniform pressure distribution in the plates can be replaced by an equivalence of uniform pressure distribution. Applied examples are presented, demonstrating that the current plate design methods of the maritime industry may be inappropriate when the non-uniformity of lateral pressure loads becomes more significant.
International Nuclear Information System (INIS)
Ruiz-Rodriguez, F.J.; Gomez-Gonzalez, M.; Jurado, F.
2013-01-01
Highlights: ► Loads and distributed generation production are modeled as random variables. ► Distribution system with biomass fueled gas engines. ► Random nature of lower heat value of biomass and load. ► The Cornish–Fisher expansion is used for approximating quantiles of a random variable. ► Computational cost is low enough than that required for Monte Carlo simulation. - Abstract: This paper shows that the technical constraints must be considered in radial distribution networks, where the voltage regulation is one of the primary problems to be dealt in distributed generation systems based on biomass fueled engine. Loads and distributed generation production are modeled as random variables. Results prove that the proposed method can be applied for the keeping of voltages within desired limits at all load buses of a distribution system with biomass fueled gas engines. To evaluate the performance of this distribution system, this paper has developed a probabilistic model that takes into account the random nature of lower heat value of biomass and load. The Cornish–Fisher expansion is used for approximating quantiles of a random variable. This work introduces a hybrid method that utilizes a new optimization method based on swarm intelligence and probabilistic radial load flow. It is demonstrated the reduction in computation time achieved by the more efficient probabilistic load flow in comparison to Monte Carlo simulation. Acceptable solutions are reached in a smaller number of iterations. Therefore, convergence is more rapidly attained and computational cost is significantly lower than that required for Monte Carlo methods.
Klemen, Jane; Büchel, Christian; Bühler, Mira; Menz, Mareike M; Rose, Michael
2010-03-01
Attentional interference between tasks performed in parallel is known to have strong and often undesired effects. As yet, however, the mechanisms by which interference operates remain elusive. A better knowledge of these processes may facilitate our understanding of the effects of attention on human performance and the debilitating consequences that disruptions to attention can have. According to the load theory of cognitive control, processing of task-irrelevant stimuli is increased by attending in parallel to a relevant task with high cognitive demands. This is due to the relevant task engaging cognitive control resources that are, hence, unavailable to inhibit the processing of task-irrelevant stimuli. However, it has also been demonstrated that a variety of types of load (perceptual and emotional) can result in a reduction of the processing of task-irrelevant stimuli, suggesting a uniform effect of increased load irrespective of the type of load. In the present study, we concurrently presented a relevant auditory matching task [n-back working memory (WM)] of low or high cognitive load (1-back or 2-back WM) and task-irrelevant images at one of three object visibility levels (0%, 50%, or 100%). fMRI activation during the processing of the task-irrelevant visual stimuli was measured in the lateral occipital cortex and found to be reduced under high, compared to low, WM load. In combination with previous findings, this result is suggestive of a more generalized load theory, whereby cognitive load, as well as other types of load (e.g., perceptual), can result in a reduction of the processing of task-irrelevant stimuli, in line with a uniform effect of increased load irrespective of the type of load.
Energy Technology Data Exchange (ETDEWEB)
Surek, D.
2001-07-30
In the field of turbo-compressors, the following problems must be solved in order to extend the range of operation: (a) Prevention of rotating stall at part load; (b) Extension of the permissible operating range at part load; (c) Extension of the operation range of radial and side channel compressors in higher vacuum below p{sub s}=50kPa. (c) can be achieved by changing the flow pattern in the rotor and in the region of interaction between the blade wheel and guide wheel of radial compressors or by actively influencing transient flow, e.g. by coupling radial compressor stages with a side channel compressor stage as final stage. The contribution goes into detail about the latter solution. [German] Fuer den Turboverdichterbau sind gegenwaertig folgende Probleme zur Erweiterung der Betriebsbereiche dringend zu loesen: (a) Vermeiden oder beseitigen von Rotating Stall im Teillastbereich,(b) Erweiterung des zulaessigen Arbeitsbereiches im Teillastgebiet, (c) Erschliessung des Arbeitsbereichs von Radial- und Seitenkanalverdichtern im hoeheren Vakuumbereich unterhalb von p{sub s}=50 kPa. Die Erweiterung des zulaessigen Arbeitsbereichs im Teillastgebiet kann durch Veraenderung der Stroemungsstruktur im Laufrad und im Interaktionsbereich zwischen Lauf- und Leitrad von Radialverdichtern oder durch die aktive Beeinflussung der instationaeren Stroemung z.B. durch Kopplung von Radialverdichterstufen mit einer Seitenkanalverdichterstufe als Endstufe erfolgen. Seitenkanalverdichter verfuegen ueber stabile Kennlinien im gesamten Betriebsbereich. Im Kombinationsbetrieb einer Radialverdichterstufe mit nach- oder vorgeschalteter Seitenkanalverdichterstufe praegte die Seitenkanalverdichterstufe dem Kombinationsverdichter ihr stabiles Kennlinienverhalten auf, so dass sich eine stabile Gesamtkennlinie ergibt. Eine Pumpgrenze tritt nicht mehr auf, so dass der Betrieb von Verdichterkombinationen aus Radial- und Seitenkanalstufe im gesamten Kennlinienbereich moeglich ist. Die
Determination of the radial profile of the photoelastic coefficient of polymer optical fibers
Acheroy, Sophie; Merken, Patrick; Geernaert, Thomas; Ottevaere, Heidi; Thienpont, Hugo; Berghmans, Francis
2016-04-01
We determine the radial profile of the photoelastic constant C(r) in two single mode and one multimode polymer optical fibers (POFs), all fabricated from polymethylmethacrylate (PMMA). To determine C(r) we first determine the retardance of the laterally illuminated fiber submitted to a known tensile stress uniformly distributed over the fiber cross-section. Then we determine the inverse Abel transform of the measured retardance to finally obtain C(r). We compare two algorithms based on the Fourier theory to perform the inverse transform. We obtain disparate distributions of C(r) in the three fibers. The mean value of C(r) varies from -7.6×10-14 to 5.4×10-12 Pa-1. This indicates that, in contrast to glass fibers, the radial profile of the photoelastic constant can considerable vary depending on the type and treatment of POFs, even when made from similar materials, and hence the photoelastic constant should be measured for each type of POF.
Kudo, Toshiya; Hara, Akira; Iwase, Hideaki; Ichihara, Satoshi; Nagao, Masashi; Maruyama, Yuichiro; Kaneko, Kazuo
2016-10-01
Previous reports have questioned whether an orthogonal or parallel configuration is superior for distal humeral articular fractures. In previous clinical and biomechanical studies, implant failure of the posterolateral plate has been reported with orthogonal configurations; however, the reason for screw loosening in the posterolateral plate is unclear. The purpose of this study was to evaluate biomechanical properties and to clarify the causes of posterolateral plate loosening using a humeral fracture model under axial compression on the radial or ulnar column separately. And we changed only the plate set up: parallel or orthogonal. We used artificial bone to create an Association for the Study of Internal Fixation type 13-C2.3 intra-articular fracture model with a 1-cm supracondylar gap. We used an anatomically-preshaped distal humerus locking compression plate system (Synthes GmbH, Solothurn, Switzerland). Although this is originally an orthogonal plate system, we designed a mediolateral parallel configuration to use the contralateral medial plate instead of the posterolateral plate in the system. We calculated the stiffness of the radial and ulnar columns and anterior movement of the condylar fragment in the lateral view. The parallel configuration was superior to the orthogonal configuration regarding the stiffness of the radial column axial compression. There were significant differences between the two configurations regarding anterior movement of the capitellum during axial loading of the radial column. The posterolateral plate tended to bend anteriorly under axial compression compared with the medial or lateral plate. We believe that in the orthogonal configuration axial compression induced more anterior displacement of the capitellum than the trochlea, which eventually induced secondary fragment or screw dislocation on the posterolateral plate, or nonunion at the supracondylar level. In the parallel configuration, anterior movement of the capitellum or
International Nuclear Information System (INIS)
Tu Yumeng; Gong Huaping; Chen Jixuan; Jin Yongxing
2011-01-01
The model of force analysis on a uniform strength beam is built by the general finite element program (ANSYS software). The flexivity profile produced by uniform strength beam with different forces is simulated by ANSYS software. In experiment, a fiber Bragg grating sensor is fixed on the uniform strength beam with modified acrylate. The flexivity and strain are varied by changing the load on the end of the beam. The strain of the uniform strength beam is measured with FBG when applied force is varied from 2.45N to14.7N with a step of 2.45N. Both the simulated and experimental results show that, the strain induced by the uniform strength beam is linear with the load force. The sensitivity is 18.32με/N for experimental measurement, and 19.72με/N for simulation. The experimental results are consistent with the simulation results, with the maximum measurement error of strain being 7.4%. It indicates that, the FBG sensor fixed with modified acrylate is proved to be effectively and reliably in the applications of civil engineering.
Directory of Open Access Journals (Sweden)
Günter Offner
2015-06-01
Full Text Available The investigation of component dynamics is one of the main tasks of internal combustion engine (ICE simulation. This prediction is important in order to understand complex loading conditions, which happen in a running ICE. Due to the need for fuel saving, mechanical friction, in particular in radial slider bearings, is one important investigation target. A generic friction modeling approach for radial slider bearings, which can be applied to lubricated contact regimes, will be presented in this paper. Besides viscous friction, the approach considers in particular boundary friction. The parameterization of the friction model is done using surface material and surface roughness measurement data. Furthermore, fluid properties depending on the applied oil additives are being considered. The application of the model will be demonstrated for a typical engineering task of a connecting rod big end study to outline the effects of contact surface texture. AlSn-based and polymer coated bearing shells will be analyzed and compared with respect to friction reduction effects, running-in behavior and thermal load capabilities.
Latitudinal Dependence of the Radial IMF Component: Coronal Imprint
Suess, S. T.; Smith, E. J.
1996-01-01
Measurements by Ulysses have confirmed that there is no significant gradient with respect to heliomagnetic latitude in the radial component, B(sub r,) of the interplanetary magnetic field. In the corona, the plasma, beta is much less than 1, except directly above streamers, so longitudinal and latitudinal gradients in field strength will relax due to the transverse magnetic pressure gradient force as the solar wind carries magnetic flux away from the Sun. This happens quickly enough so that the field is essentially uniform by 5 - 10 solar radius, apparently remaining so as it is carried to beyond 1 AU. Here, we illustrate the coronal relaxation with a qualitative physical argument and by reference to a detailed Magneto HydroDynamics (MHD) simulation.
Improved abdominal MRI in non-breath-holding children using a radial k-space sampling technique
Energy Technology Data Exchange (ETDEWEB)
Lee, Jong Hyuk; Choi, Young Hun; Cheon, Jung Eun; Lee, So Mi; Cho, Hyun Hae; Kim, Woo Sun; Kim, In One [Seoul National University Children' s Hospital, Department of Radiology, Seoul (Korea, Republic of); Shin, Su Mi [SMG-SNU Boramae Medical Center, Department of Radiology, Seoul (Korea, Republic of)
2015-06-15
Radial k-space sampling techniques have been shown to reduce motion artifacts in adult abdominal MRI. To compare a T2-weighted radial k-space sampling MRI pulse sequence (BLADE) with standard respiratory-triggered T2-weighted turbo spin echo (TSE) in pediatric abdominal imaging. Axial BLADE and respiratory-triggered turbo spin echo sequences were performed without fat suppression in 32 abdominal MR examinations in children. We retrospectively assessed overall image quality, the presence of respiratory, peristaltic and radial artifact, and lesion conspicuity. We evaluated signal uniformity of each sequence. BLADE showed improved overall image quality (3.35 ± 0.85 vs. 2.59 ± 0.59, P < 0.001), reduced respiratory motion artifact (0.51 ± 0.56 vs. 1.89 ± 0.68, P < 0.001), and improved lesion conspicuity (3.54 ± 0.88 vs. 2.92 ± 0.77, P = 0.006) compared to respiratory triggering turbo spin-echo (TSE) sequences. The bowel motion artifact scores were similar for both sequences (1.65 ± 0.77 vs. 1.79 ± 0.74, P = 0.691). BLADE introduced a radial artifact that was not observed on the respiratory triggering-TSE images (1.10 ± 0.85 vs. 0, P < 0.001). BLADE was associated with diminished signal variation compared with respiratory triggering-TSE in the liver, spleen and air (P < 0.001). The radial k-space sampling technique improved the quality and reduced respiratory motion artifacts in young children compared with conventional respiratory-triggered turbo spin-echo sequences. (orig.)
EXPERIMENTAL EVALUATION OF THE FULLY LOADED ELK RIVER REACTOR
Energy Technology Data Exchange (ETDEWEB)
Fisher, J. R.; Diaz, A.
1963-06-15
The loading and testing program of the Elk River Reactor confirmed the predicted values. The measured cold, clean excess reactivity agrees to 2% and the control rod worths to 1% of the calculated values. The reactivity for various core loadings and rod positions is tabulated. The effects of spiked elements on the reactivity and radial peak-toaverage power ratio were studied. (D.L.C.)
Structural changes of radial forging die surface during service under thermo-mechanical fatigue
International Nuclear Information System (INIS)
Nematzadeh, Fardin; Akbarpour, Mohammad Reza; Kokabi, Amir Hosein; Sadrnezhaad, Seyed Khatiboleslam
2009-01-01
Radial forging is one of the modern open die forging techniques and has a wide application in producing machine parts. During operation at high temperatures, severe temperature change associated with mechanical loads and the resultant wearing of the die surface lead to intense variation in strain on the die surface. Therefore, under this operating condition, thermo-mechanical fatigue (TMF) occurs on the surface of the radial forging die. TMF decreases the life of the die severely. In the present research, different layers were deposited on a 1.2714 steel die by SMAW and GTAW, with a weld wire of UDIMET 520. The microstructure of the radial forging die surface was investigated during welding and service using an optical microscope and scanning electron microscope. The results revealed that, after welding, the structure of the radial forging die surface includes the γ matrix with a homogeneous distribution of fine semi-spherical carbides. The weld structure consisted mostly of columnar dendrites with low grain boundaries. Also, microstructural investigation of the die surface during operation showed that the weld structure of the die surface has remained without any considerable change. Only dendrites were deformed and broken. Moreover, grain boundaries of the dendrites were revealed during service.
Antiproton compression and radial measurements
Andresen, G B; Bowe, P D; Bray, C C; Butler, E; Cesar, C L; Chapman, S; Charlton, M; Fajans, J; Fujiwara, M C; Funakoshi, R; Gill, D R; Hangst, J S; Hardy, W N; Hayano, R S; Hayden, M E; Humphries, A J; Hydomako, R; Jenkins, M J; Jorgensen, L V; Kurchaninov, L; Lambo, R; Madsen, N; Nolan, P; Olchanski, K; Olin, A; Page R D; Povilus, A; Pusa, P; Robicheaux, F; Sarid, E; Seif El Nasr, S; Silveira, D M; Storey, J W; Thompson, R I; Van der Werf, D P; Wurtele, J S; Yamazaki, Y
2008-01-01
Control of the radial proﬁle of trapped antiproton clouds is critical to trapping antihydrogen. We report detailed measurements of the radial manipulation of antiproton clouds, including areal density compressions by factors as large as ten, achieved by manipulating spatially overlapped electron plasmas. We show detailed measurements of the near-axis antiproton radial proﬁle, and its relation to that of the electron plasma. We also measure the outer radial proﬁle by ejecting antiprotons to the trap wall using an octupole magnet.
Temperature uniformity in the CERN CLOUD chamber
Directory of Open Access Journals (Sweden)
A. Dias
2017-12-01
Full Text Available The CLOUD (Cosmics Leaving OUtdoor Droplets experiment at CERN (European Council for Nuclear Research investigates the nucleation and growth of aerosol particles under atmospheric conditions and their activation into cloud droplets. A key feature of the CLOUD experiment is precise control of the experimental parameters. Temperature uniformity and stability in the chamber are important since many of the processes under study are sensitive to temperature and also to contaminants that can be released from the stainless steel walls by upward temperature fluctuations. The air enclosed within the 26 m3 CLOUD chamber is equipped with several arrays (strings of high precision, fast-response thermometers to measure its temperature. Here we present a study of the air temperature uniformity inside the CLOUD chamber under various experimental conditions. Measurements were performed under calibration conditions and run conditions, which are distinguished by the flow rate of fresh air and trace gases entering the chamber at 20 and up to 210 L min−1, respectively. During steady-state calibration runs between −70 and +20 °C, the air temperature uniformity is better than ±0.06 °C in the radial direction and ±0.1 °C in the vertical direction. Larger non-uniformities are present during experimental runs, depending on the temperature control of the make-up air and trace gases (since some trace gases require elevated temperatures until injection into the chamber. The temperature stability is ±0.04 °C over periods of several hours during either calibration or steady-state run conditions. During rapid adiabatic expansions to activate cloud droplets and ice particles, the chamber walls are up to 10 °C warmer than the enclosed air. This results in temperature differences of ±1.5 °C in the vertical direction and ±1 °C in the horizontal direction, while the air returns to its equilibrium temperature with a time constant of about 200 s.
MORPHOLOGICAL ADJUSTMENTS OF THE RADIAL NERVE ARE INTENSITY-DEPENDENT
Directory of Open Access Journals (Sweden)
Patrícia Oliva Carbone
Full Text Available ABSTRACT Introduction: Peripheral nerve adaptation is critical for strength gains. However, information about intensity effects on nerve morphology is scarce. Objective: To compare the effects of different intensities of resistance training on radial nerve structures. Methods: Rats were divided into three groups: control (GC, training with 50% (GF1 and training 75% (GF2 of the animal’s body weight. The morphological analysis of the nerve was done by light and transmission electron microscopy. One-way ANOVA and the Tukey’s post hoc test were applied and the significance level was set at p≤0.05. Results: Training groups had an increase of strength compared to GC (p≤0.05. All measured nerve components (mean area and diameter of myelin fibers and axons, mean area and thickness of the myelin sheath, and of neurofilaments and microtubules were higher in GF2 compared to the other (p≤0.05. Conclusion: Results demonstrated greater morphological changes on radial nerve after heavier loads. This can be important for rehabilitation therapies, training, and progression.
Skin carcinogenesis following uniform and non-uniform β irradiation
International Nuclear Information System (INIS)
Charles, M.W.; Williams, J.P.; Coggle, J.E.
1989-01-01
Where workers or the general public may be exposed to ionising radiation, the irradiation is rarely uniform. The risk figures and dose limits recommended by the International Commission on Radiological Protection (ICRP) are based largely on clinical and epidemiological studies of reasonably uniform irradiated organs. The paucity of clinical or experimental data for highly non-uniform exposures has prevented the ICRP from providing adequate recommendations. This weakness has led on a number of occasions to the postulate that highly non-uniform exposures of organs could be 100,000 times more carcinogenic than ICRP risk figures would predict. This so-called ''hot-particle hypothesis'' found little support among reputable radiobiologists, but could not be clearly and definitively refuted on the basis of experiment. An experiment, based on skin tumour induction in mouse skin, is described which was developed to test the hypothesis. The skin of 1200 SAS/4 male mice has been exposed to a range of uniform and non-uniform sources of the β emitter 170 Tm (E max ∼ 1 MeV). Non-uniform exposures were produced using arrays of 32 or 8 2-mm diameter sources distributed over the same 8-cm 2 area as a uniform control source. Average skin doses varied from 2-100 Gy. The results for the non-uniform sources show a 30% reduction in tumour incidence by the 32-point array at the lower mean doses compared with the response from uniform sources. The eight-point array showed an order-of-magnitude reduction in tumour incidence compared to uniform irradiation at low doses. These results, in direct contradiction to the ''hot particle hypothesis'', indicate that non-uniform exposures produce significantly fewer tumours than uniform exposures. (author)
Directory of Open Access Journals (Sweden)
Moutaz Elgammi
2016-06-01
Full Text Available Prediction of the unsteady aerodynamic flow phenomenon on wind turbines is challenging and still subject to considerable uncertainty. Under yawed rotor conditions, the wind turbine blades are subjected to unsteady flow conditions as a result of the blade advancing and retreating effect and the development of a skewed vortical wake created downstream of the rotor plane. Blade surface pressure measurements conducted on the NREL Phase VI rotor in yawed conditions have shown that dynamic stall causes the wind turbine blades to experience significant cycle-to-cycle variations in aerodynamic loading. These effects were observed even though the rotor was subjected to a fixed speed and a uniform and steady wind flow. This phenomenon is not normally predicted by existing dynamic stall models integrated in wind turbine design codes. This paper couples blade pressure measurements from the NREL Phase VI rotor to a free-wake vortex model to derive the angle of attack time series at the different blade sections over multiple rotor rotations and three different yaw angles. Through the adopted approach it was possible to investigate how the rotor self-induced aerodynamic load fluctuations influence the unsteady variations in the blade angles of attack and induced velocities. The hysteresis loops for the normal and tangential load coefficients plotted against the angle of attack were plotted over multiple rotor revolutions. Although cycle-to-cycle variations in the angles of attack at the different blade radial locations and azimuth positions are found to be relatively small, the corresponding variations in the normal and tangential load coefficients may be significant. Following a statistical analysis, it was concluded that the load coefficients follow a normal distribution at the majority of blade azimuth angles and radial locations. The results of this study provide further insight on how existing engineering models for dynamic stall may be improved through
Linear elastic analysis of pavement structure under non-circular loading
CSIR Research Space (South Africa)
Maina, JW
2012-10-01
Full Text Available the development of a method for pavement structural analysis considering both uniform and non-uniform loads acting over a rectangular area. In this approach, three components of displacements, which satisfy Navier’s equations, are expressed using Neuber...
Stability of radial swirl flows
International Nuclear Information System (INIS)
Dou, H S; Khoo, B C
2012-01-01
The energy gradient theory is used to examine the stability of radial swirl flows. It is found that the flow of free vortex is always stable, while the introduction of a radial flow will induce the flow to be unstable. It is also shown that the pure radial flow is stable. Thus, there is a flow angle between the pure circumferential flow and the pure radial flow at which the flow is most unstable. It is demonstrated that the magnitude of this flow angle is related to the Re number based on the radial flow rate, and it is near the pure circumferential flow. The result obtained in this study is useful for the design of vaneless diffusers of centrifugal compressors and pumps as well as other industrial devices.
A novel compliance measurement in radial arteries using strain-gauge plethysmography
International Nuclear Information System (INIS)
Liu, Shing-Hong; Tyan, Chu-Chang; Chang, Kang-Ming
2009-01-01
We propose a novel method for assessing the compliance of the radial artery by using a two-axis mechanism and a standard positioning procedure for detecting the optimal measuring site. A modified sensor was designed to simultaneously measure the arterial diameter change waveform (ADCW) and pressure pulse waveform with a strain gauge and piezoresistor. In the x-axis scanning, the sensor could be placed close to the middle of the radial artery when the ADCW reached the maximum amplitude. In the z-axis scanning, the contact pressure was continuously increased for data measurement. Upon the deformation of the strain gauge following the change in the vascular cross-section, the ADCW was transferred to the change of the vascular radius. The loaded strain compliance of the radial artery (C strain ) can be determined by dividing the dynamic changed radius by the pulse pressure. Twenty-three untreated, mild or moderate hypertensive patients aged 29–85 were compared with 14 normotensive patients aged 25–62. The maximum strain compliance between the two groups was significantly different (p < 0.005). Of the hypertensive patients, 14 were at risk of developing hyperlipidemia. There was a significant difference between this and the normotension group (p < 0.005)
A novel compliance measurement in radial arteries using strain-gauge plethysmography.
Liu, Shing-Hong; Tyan, Chu-Chang; Chang, Kang-Ming
2009-09-01
We propose a novel method for assessing the compliance of the radial artery by using a two-axis mechanism and a standard positioning procedure for detecting the optimal measuring site. A modified sensor was designed to simultaneously measure the arterial diameter change waveform (ADCW) and pressure pulse waveform with a strain gauge and piezoresistor. In the x-axis scanning, the sensor could be placed close to the middle of the radial artery when the ADCW reached the maximum amplitude. In the Z-axis scanning, the contact pressure was continuously increased for data measurement. Upon the deformation of the strain gauge following the change in the vascular cross-section, the ADCW was transferred to the change of the vascular radius. The loaded strain compliance of the radial artery (C(strain)) can be determined by dividing the dynamic changed radius by the pulse pressure. Twenty-three untreated, mild or moderate hypertensive patients aged 29-85 were compared with 14 normotensive patients aged 25-62. The maximum strain compliance between the two groups was significantly different (p < 0.005). Of the hypertensive patients, 14 were at risk of developing hyperlipidemia. There was a significant difference between this and the normotension group (p < 0.005).
Xie, Cai-Xia; Zhang, Miao; Li, Ya-Jing; Geng, Xiao-Tong; Wang, Feng-Qing; Zhang, Zhong-Yi
2017-11-01
An HPLC method was established to determine the contents of catalpol, acteoside, rehmaionoside A, rehmaionoside D, leonuride in three part of Rehmanni glutinosa in Beijing No.1 variety R. glutinosa during the growth period, This method, in combination with its HPLC fingerprint was used to evaluate its overall quality characteristics.The results showed that：① the content of main components of R. glutinosa varied in different growth stages ;② there was a great difference of the content of main components between theradial striations and the non-radial striations; ③ the two sections almost have the same content distribution of catalpol, acteoside and rehmaionoside D; ④the content of rehmaionoside A in non-radial striations was higher than that in radial striations,while the content of leonuride in radial striations was higher than that in non-radial striations.; ⑤the HPLC fingerprint of radial striations, non-radial striations and whole root tuber were basically identical, except for the big difference in the content of chemical components. The result of clustering displayed that the radial striations, non-radial striations, and whole root were divided into two groups. In conclusion, there was a significant difference in the quality characteristics of radial striations and non-radial striations of R. glutinosa. This research provides a reference for quality evaluation and geoherbalism of R. glutinosa. Copyright© by the Chinese Pharmaceutical Association.
A model for radial cesium transport in a fuel pellet
International Nuclear Information System (INIS)
Imoto, Shosuke
1989-01-01
In order to explain the radial redistribution of cesium in an irradiated pellet, a two-step release model is proposed. The first step involves the migration of cesium by atomic diffusion to some channels, such as grain boundaries and cracks, and the second step assumes a thermomigration down along the temperature gradient. Distribution profiles of cesium are obtained by numerical calculation with the present model assuming a constant and spatially uniform birth rate of cesium in the pellet. The result agrees well with the profile observed by micro-gamma scanning for the LWR fuel in the outer region of the pellet but diverges from it at the inner region. Discussion is made on the steady-state model hitherto generally utilized. (orig.)
International Nuclear Information System (INIS)
Maxwell, R.L.; Holland, R.W.; Stengl, G.R.
1970-06-01
The report presents the results of investigations conducted on a hemisphere with a radial nozzle of 7.875'' O.D. and 7.500'' I.D. and 10'' penetration into the hemisphere. Stress values were determined for the following five types of loadings: (1) internal pressure applied to the hemisphere and nozzle assembly, (2) an axial load applied collinear with nozzle, (3) a pure bending moment, or axial couple, applied to the nozzle, (4) a transverse or shear load applied normal to the nozzle, and (5) a pure torque applied in the radial plane of the nozzle
Stress-intensity factors for cracks emanating from the loaded fastener hole
Shivakumar, V.; Hsu, Y. C.
1977-01-01
Using a series approach and the Muskhelishvili formulation in the two-dimensional theory of elasticity, stress-intensity factors K are derived for problems in which cracks emanate radially from the boundary of an arbitrarily loaded internal circular hole in an infinite plate. Numerical values are obtained for K(I) and K(II) for radial cracks from a hole containing a loose-fitted pin or rivet that is pulled perpendicular to the crack direction in the plane of the plate. The method is a general one for determining K for a set of symmetrically emanating radial cracks for a variety of concentrated or distributed tractions on the circular hole.
International Nuclear Information System (INIS)
Wiencek, T.C.; Domagala, R.F.; Thresh, H.R.
1990-01-01
Two embodiments of a high uranium fuel plate are disclosed which contain a meat comprising structured uranium compound confined between a pari of diffusion bonded ductile metal cladding plates uniformly covering the meat, the meat hiving a uniform high fuel loading comprising a content of uranium compound greater than about 45 Vol. % at a porosity not greater than about 10 Vol. %. In a first embodiment, the meat is a plurality of parallel wires of uranium compound. In a second embodiment, the meat is a dispersion compact containing uranium compound. The fuel plates are fabricated by a hot isostatic pressing process
Miller, Arthur L; Drake, Pamela L; Murphy, Nathaniel C; Cauda, Emanuele G; LeBouf, Ryan F; Markevicius, Gediminas
Miners are exposed to silica-bearing dust which can lead to silicosis, a potentially fatal lung disease. Currently, airborne silica is measured by collecting filter samples and sending them to a laboratory for analysis. Since this may take weeks, a field method is needed to inform decisions aimed at reducing exposures. This study investigates a field-portable Fourier transform infrared (FTIR) method for end-of-shift (EOS) measurement of silica on filter samples. Since the method entails localized analyses, spatial uniformity of dust deposition can affect accuracy and repeatability. The study, therefore, assesses the influence of radial deposition uniformity on the accuracy of the method. Using laboratory-generated Minusil and coal dusts and three different types of sampling systems, multiple sets of filter samples were prepared. All samples were collected in pairs to create parallel sets for training and validation. Silica was measured by FTIR at nine locations across the face of each filter and the data analyzed using a multiple regression analysis technique that compared various models for predicting silica mass on the filters using different numbers of "analysis shots." It was shown that deposition uniformity is independent of particle type (kaolin vs. silica), which suggests the role of aerodynamic separation is negligible. Results also reflected the correlation between the location and number of shots versus the predictive accuracy of the models. The coefficient of variation (CV) for the models when predicting mass of validation samples was 4%-51% depending on the number of points analyzed and the type of sampler used, which affected the uniformity of radial deposition on the filters. It was shown that using a single shot at the center of the filter yielded predictivity adequate for a field method, (93% return, CV approximately 15%) for samples collected with 3-piece cassettes.
International Nuclear Information System (INIS)
Ida, Katsumi; Miura, Yukitoshi; Itoh, Sanae
1994-10-01
Radial structures of plasma rotation and radial electric field are experimentally studied in tokamak, heliotron/torsatron and stellarator devices. The perpendicular and parallel viscosities are measured. The parallel viscosity, which is dominant in determining the toroidal velocity in heliotron/torsatron and stellarator devices, is found to be neoclassical. On the other hand, the perpendicular viscosity, which is dominant in dictating the toroidal rotation in tokamaks, is anomalous. Even without external momentum input, both a plasma rotation and a radial electric field exist in tokamaks and heliotrons/torsatrons. The observed profiles of the radial electric field do not agree with the theoretical prediction based on neoclassical transport. This is mainly due to the existence of anomalous perpendicular viscosity. The shear of the radial electric field improves particle and heat transport both in bulk and edge plasma regimes of tokamaks. (author) 95 refs
Comparative analysis of the construction solution variants for flat arch coverings of buildings
Directory of Open Access Journals (Sweden)
Ibragimov Aleksandr Mayorovich
2014-03-01
Full Text Available Arch structures of long span buildings’ coverings are more beneficial in respect to material expenses, than beam and frame systems. Constructive schemes of roof frameworks of arch coverings are diverse, which means their operation under loading differs much. The authors offer a number of construction solutions for flat arch coverings of long span buildings. The comparative analysis of these construction solutions is presented. The operation of radial link arch is observed. The arch consists of discontinuous top chord and radial bowstring under the single load (uniformly distributed and concentrated in nods with different spans and rises. The problem of radial link arch optimization is solved in dependence with arising forces and rise. The optimal camber of arch was found. In further works the authors plan to analyze spans more than 36 meters and solve the problem in case of asymmetrical loadings.
Laterally Loaded Partially Prestressed Concrete Piles
1989-09-01
of an extensive test program onl laterali y ioadeu. partially pr- estressed concrete fender piles. The study Included service load range as well ats...12,000-psi design strength). Configura- tion G utilized 14 r:- estress strand, in an unsymmetric pattern. To provide a uniform concrete prestress of 540...sudden loss in load carrying capacity directly related to the loss of concrete area. The compression concrete fractured longitudinally and along the
Enceladus's crust as a non-uniform thin shell: I tidal deformations
Beuthe, Mikael
2018-03-01
The geologic activity at Enceladus's south pole remains unexplained, though tidal deformations are probably the ultimate cause. Recent gravity and libration data indicate that Enceladus's icy crust floats on a global ocean, is rather thin, and has a strongly non-uniform thickness. Tidal effects are enhanced by crustal thinning at the south pole, so that realistic models of tidal tectonics and dissipation should take into account the lateral variations of shell structure. I construct here the theory of non-uniform viscoelastic thin shells, allowing for depth-dependent rheology and large lateral variations of shell thickness and rheology. Coupling to tides yields two 2D linear partial differential equations of the fourth order on the sphere which take into account self-gravity, density stratification below the shell, and core viscoelasticity. If the shell is laterally uniform, the solution agrees with analytical formulas for tidal Love numbers; errors on displacements and stresses are less than 5% and 15%, respectively, if the thickness is less than 10% of the radius. If the shell is non-uniform, the tidal thin shell equations are solved as a system of coupled linear equations in a spherical harmonic basis. Compared to finite element models, thin shell predictions are similar for the deformations due to Enceladus's pressurized ocean, but differ for the tides of Ganymede. If Enceladus's shell is conductive with isostatic thickness variations, surface stresses are approximately inversely proportional to the local shell thickness. The radial tide is only moderately enhanced at the south pole. The combination of crustal thinning and convection below the poles can amplify south polar stresses by a factor of 10, but it cannot explain the apparent time lag between the maximum plume brightness and the opening of tiger stripes. In a second paper, I will study the impact of a non-uniform crust on tidal dissipation.
McGovern, P. J., Jr.; Grosfils, E. B.; Le Corvec, N.; Ernst, R. E.; Galgana, G. A.
2017-12-01
Over 200 giant radial dike swarms have been identified on Venus using Magellan data, yielding insight into morphological characteristics long since erased by erosion and other processes on Earth. Since such radial dike systems are typically associated with magma reservoirs, large volcanoes and/or larger-scale plume activity—and because dike geometry reflects stress conditions at the time of intrusion—assessing giant radial dike formation in the context of swarm morphology can place important constraints upon this fundamental volcanotectonic process. Recent numerical models reveal that, contrary to what is reported in much of the published literature, it is not easy, mechanically, to produce either large or small radial dike systems. After extensive numerical examination of reservoir inflation, however, under conditions ranging from a simple halfspace to complex flexural loading, we have thus far identified four scenarios that produce radial dike systems. Two of these scenarios yield dike systems akin to those often associated with shield and stratocone volcanoes on Earth, while the other two, our focus here, are more consistent with the giant radial dike system geometries catalogued on Venus. In this presentation we will (a) review key morphological characteristics of the giant radial systems identified on Venus, (b) briefly illustrate why it is not easy, mechanically, to produce a radial dike system, (c) present the two volcanological circumstances we have identified that do allow a giant radial dike system to form, and (d) discuss current model limitations and potentially fruitful directions for future research.
Davis, Pamela A.; Lopez, Mercedes C.
1987-01-01
An investigation was conducted to determine the static mechanical characteristics of 30 x 115-14.5 bias-ply and radial aircraft tires. The tires were subjected to vertical and lateral loads and mass moment of inertia tests were conducted. Static load deflection curves, spring rates, hysteresis losses, and inertia data are presented along with a discussion of the advantages and disadvantages of one tire over the other.
Radial retinotomy in the macula.
Bovino, J A; Marcus, D F
1984-01-01
Radial retinotomy is an operative procedure usually performed in the peripheral or equatorial retina. To facilitate retinal attachment, the authors used intraocular scissors to perform radial retinotomy in the macula of two patients during vitrectomy surgery. In the first patient, a retinal detachment complicated by periretinal proliferation and macula hole formation was successfully reoperated with the aid of three radial cuts in the retina at the edges of the macular hole. In the second patient, an intraoperative retinal tear in the macula during diabetic vitrectomy was also successfully repaired with the aid of radial retinotomy. In both patients, retinotomy in the macula was required because epiretinal membranes, which could not be easily delaminated, were hindering retinal reattachment.
Diagnostics of load vibrations at the inlet of a mechanism
Dontsu, V. P.; Dontsu, Z. T.; Ragulskis, K. M.; Savka, N. M.
1973-01-01
The torque of a drive shaft in a magnetic recording device was studied by oscillographic recordings. Statistical evaluation of the dynamic spectral densities showed that the principle source of disturbing forces is loading in the drive shaft radial play.
Radial head dislocation during proximal radial shaft osteotomy.
Hazel, Antony; Bindra, Randy R
2014-03-01
The following case report describes a 48-year-old female patient with a longstanding both-bone forearm malunion, who underwent osteotomies of both the radius and ulna to improve symptoms of pain and lack of rotation at the wrist. The osteotomies were templated preoperatively. During surgery, after performing the planned radial shaft osteotomy, the authors recognized that the radial head was subluxated. The osteotomy was then revised from an opening wedge to a closing wedge with improvement of alignment and rotation. The case report discusses the details of the operation, as well as ways in which to avoid similar shortcomings in the future. Copyright © 2014 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.
Maina, J W; Kawana, F; Matsui, K
2017-01-01
In order to better understand the impact of increased loading on roads, studies on tyre-road interaction have gained prominence in recent years. Tyres form an essential interface between vehicles and road pavement surfaces. These are the only parts of the vehicle that are in contact with the road and transmit the vehicle loading to the road surface. The use of the Cartesian coordinate system is convenient in dealing with a uniform/non-uniform tyre load acting over a rectangular area, but few ...
Radial cracks and fracture mechanism of radially oriented ring 2:17 type SmCo magnets
International Nuclear Information System (INIS)
Tian Jianjun; Pan Dean; Zhou Hao; Yin Fuzheng; Tao Siwu; Zhang Shengen; Qu Xuanhui
2009-01-01
Radially oriented ring 2:17 type SmCo magnets have different microstructure in the radial direction (easy magnetization) and axial direction (hard magnetization). The structure of the cross-section in radial direction is close-packed atomic plane, which shows cellular microstructure. The microstructure of the cross-section in axial direction consists of a mixture of rhombic microstructure and parallel lamella phases. So the magnets have obvious anisotropy of thermal expansion in different directions. The difference of the thermal expansion coefficients reaches the maximum value at 830-860 deg. C, which leads to radial cracks during quenching. The magnets have high brittlement because there are fewer slip systems in crystal structure. The fracture is brittle cleavage fracture.
Assessment indices for uniform and non-uniform thermal environments
Institute of Scientific and Technical Information of China (English)
2008-01-01
Different assessment indices for thermal environments were compared and selected for proper assessment of indoor thermal environments.30 subjects reported their overall thermal sensation,thermal comfort,and thermal acceptability in uniform and non-uniform conditions.The results show that these three assessment indices provide equivalent evaluations in uniform environments.However,overall thermal sensation differs from the other two indices and cannot be used as a proper index for the evaluation of non-uniform environments.The relationship between the percentage and the mean vote for each index is established.
Design of an Annular Disc Subject to Thermomechanical Loading
Directory of Open Access Journals (Sweden)
Sergei Alexandrov
2012-01-01
Full Text Available Two solutions to design a thin annular disc of variable thickness subject to thermomechanical loading are proposed. It is assumed that the thickness of the disc is everywhere sufficiently small for the stresses to be averaged through the thickness. The state of stress is plane. The initiation of plastic yielding is controlled by Mises yield criterion. The design criterion for one of the solutions proposed requires that the distribution of stresses is uniform over the entire disc. In this case there is a relation between optimal values of the loading parameters at the final stage. The specific shape of the disc corresponds to each pair of such parameters. The other solution is obtained under the additional requirement that the distribution of strains is uniform. This solution exists for the disc of constant thickness at specific values of the loading parameters.
International Nuclear Information System (INIS)
Lim, Teik-Cheng
2016-01-01
For moderately thick plates, the use of First order Shear Deformation Theory (FSDT) with a constant shear correction factor of 5/6 is sufficient to take into account the plate deflection arising from transverse shear deformation. For very thick plates, the use of Third order Shear Deformation Theory (TSDT) is preferred as it allows the shear strain distribution to be varied through the plate thickness. Therefore no correction factor is required in TSDT, unlike FSDT. Due to the complexity involved in TSDT, this paper obtains a more accurate shear correction factor for use in FSDT of very thick simply supported and uniformly loaded isosceles right triangular plates based on the TSDT. By matching the maximum deflections for this plate according to FSDT and TSDT, a variable shear correction factor is obtained. Results show that the shear correction factor for the simplified TSDT, i.e. 14/17, is least accurate. The commonly adopted shear correction factor of 5/6 in FSDT is valid only for very thin or highly auxetic plates. This paper provides a variable shear correction for FSDT deflection that matches the plate deflection by TSDT. This variable shear correction factor allows designers to justify the use of a commonly adopted shear correction factor of 5/6 even for very thick plates as long as the Poisson’s ratio of the plate material is sufficiently negative. (paper)
An enhanced radial basis function network for short-term electricity price forecasting
International Nuclear Information System (INIS)
Lin, Whei-Min; Gow, Hong-Jey; Tsai, Ming-Tang
2010-01-01
This paper proposed a price forecasting system for electric market participants to reduce the risk of price volatility. Combining the Radial Basis Function Network (RBFN) and Orthogonal Experimental Design (OED), an Enhanced Radial Basis Function Network (ERBFN) has been proposed for the solving process. The Locational Marginal Price (LMP), system load, transmission flow and temperature of the PJM system were collected and the data clusters were embedded in the Excel Database according to the year, season, workday and weekend. With the OED applied to learning rates in the ERBFN, the forecasting error can be reduced during the training process to improve both accuracy and reliability. This would mean that even the ''spikes'' could be tracked closely. The Back-propagation Neural Network (BPN), Probability Neural Network (PNN), other algorithms, and the proposed ERBFN were all developed and compared to check the performance. Simulation results demonstrated the effectiveness of the proposed ERBFN to provide quality information in a price volatile environment. (author)
Energy Technology Data Exchange (ETDEWEB)
Lell, R. M.; Morman, J. A.; Schaefer, R.W.; McKnight, R.D.; Nuclear Engineering Division
2009-02-23
ZPR-6 Assembly 7 (ZPR-6/7) encompasses a series of experiments performed at the ZPR-6 facility at Argonne National Laboratory in 1970 and 1971 as part of the Demonstration Reactor Benchmark Program (Reference 1). Assembly 7 simulated a large sodium-cooled LMFBR with mixed oxide fuel, depleted uranium radial and axial blankets, and a core H/D near unity. ZPR-6/7 was designed to test fast reactor physics data and methods, so configurations in the Assembly 7 program were as simple as possible in terms of geometry and composition. ZPR-6/7 had a very uniform core assembled from small plates of depleted uranium, sodium, iron oxide, U{sub 3}O{sub 8} and Pu-U-Mo alloy loaded into stainless steel drawers. The steel drawers were placed in square stainless steel tubes in the two halves of a split table machine. ZPR-6/7 had a simple, symmetric core unit cell whose neutronic characteristics were dominated by plutonium and {sup 238}U. The core was surrounded by thick radial and axial regions of depleted uranium to simulate radial and axial blankets and to isolate the core from the surrounding room. The ZPR-6/7 program encompassed 139 separate core loadings which include the initial approach to critical and all subsequent core loading changes required to perform specific experiments and measurements. In this context a loading refers to a particular configuration of fueled drawers, radial blanket drawers and experimental equipment (if present) in the matrix of steel tubes. Two principal core configurations were established. The uniform core (Loadings 1-84) had a relatively uniform core composition. The high {sup 240}Pu core (Loadings 85-139) was a variant on the uniform core. The plutonium in the Pu-U-Mo fuel plates in the uniform core contains 11% {sup 240}Pu. In the high {sup 240}Pu core, all Pu-U-Mo plates in the inner core region (central 61 matrix locations per half of the split table machine) were replaced by Pu-U-Mo plates containing 27% {sup 240}Pu in the plutonium
Perceived radial translation during centrifugation
Bos, J.E.; Correia Grácio, B.J.
2015-01-01
BACKGROUND: Linear acceleration generally gives rise to translation perception. Centripetal acceleration during centrifugation, however, has never been reported giving rise to a radial, inward translation perception. OBJECTIVE: To study whether centrifugation can induce a radial translation
International Nuclear Information System (INIS)
Hazeltine, R.D.
1988-12-01
The boundary layer arising in the radial vicinity of a tokamak limiter is examined, with special reference to the TEXT tokamak. It is shown that sheath structure depends upon the self-consistent effects of ion guiding-center orbit modification, as well as the radial variation of E /times/ B-induced toroidal rotation. Reasonable agreement with experiment is obtained from an idealized model which, however simplified, preserves such self-consistent effects. It is argued that the radial sheath, which occurs whenever confining magnetic field-lines lie in the plasma boundary surface, is an object of some intrinsic interest. It differs from the more familiar axial sheath because magnetized charges respond very differently to parallel and perpendicular electric fields. 11 refs., 1 fig
Puetzer, Jennifer L; Bonassar, Lawrence J
2016-07-01
The meniscus is a dense fibrocartilage tissue that withstands the complex loads of the knee via a unique organization of collagen fibers. Attempts to condition engineered menisci with compression or tensile loading alone have failed to reproduce complex structure on the microscale or anatomic scale. Here we show that axial loading of anatomically shaped tissue-engineered meniscus constructs produced spatial distributions of local strain similar to those seen in the meniscus when the knee is loaded at full extension. Such loading drove formation of tissue with large organized collagen fibers, levels of mechanical anisotropy, and compressive moduli that match native tissue. Loading accelerated the development of native-sized and aligned circumferential and radial collagen fibers. These loading patterns contained both tensile and compressive components that enhanced the major biochemical and functional properties of the meniscus, with loading significantly improved glycosaminoglycan (GAG) accumulation 200-250%, collagen accumulation 40-55%, equilibrium modulus 1000-1800%, and tensile moduli 500-1200% (radial and circumferential). Furthermore, this study demonstrates local changes in mechanical environment drive heterogeneous tissue development and organization within individual constructs, highlighting the importance of recapitulating native loading environments. Loaded menisci developed cartilage-like tissue with rounded cells, a dense collagen matrix, and increased GAG accumulation in the more compressively loaded horns, and fibrous collagen-rich tissue in the more tensile loaded outer 2/3, similar to native menisci. Loaded constructs reached a level of organization not seen in any previous engineered menisci and demonstrate great promise as meniscal replacements.
Static and transient beam loading of a synchrotron
International Nuclear Information System (INIS)
Zhang, S.Y.; Weng, W.T.
1992-01-01
In a synchrotron, when the beam induced current is comparable to the driver current, the RF cavity is subjected to beam loading perturbation and corrective steps have to be implemented to regain beam stability. In this paper, the static and transient beam loading will be studied. We first discuss the static beam loading, which includes the cavity detuning condition, the stability condition, and the generator power dissipation. The beam current induced beam phase deviation is used as criterion to study the transient beam loading. The upgraded and the old AGS RF system parameters are used as an example to demonstrate how to choose cavity and generator parameters to satisfy the stability requirements under the beam loading. The dynamic models for the beam loading with beam control, and the beam loading with fast power amplifier feedback are presented and analyzed. It is shown that the beam phase and radial feedbacks alone are insufficient for the transient beam loading compensation, but the fast power amplifier feedback can provide effective correction on the beam loading. The limitation of the fast feedback and the beam loading with tuning and AVC loops are also discussed
Non-uniform plastic deformation of micron scale objects
DEFF Research Database (Denmark)
Niordson, Christian Frithiof; Hutchinson, J. W.
2003-01-01
Significant increases in apparent flow strength are observed when non-uniform plastic deformation of metals occurs at the scale ranging from roughly one to ten microns. Several basic plane strain problems are analyzed numerically in this paper based on a new formulation of strain gradient...... plasticity. The problems are the tangential and normal loading of a finite rectangular block of material bonded to rigid platens and having traction-free ends, and the normal loading of a half-space by a flat, rigid punch. The solutions illustrate fundamental features of plasticity at the micron scale...... that are not captured by conventional plasticity theory. These include the role of material length parameters in establishing the size dependence of strength and the elevation of resistance to plastic flow resulting from constraint on plastic flow at boundaries. Details of the finite element method employed...
International Nuclear Information System (INIS)
Xian Chunyu; Zhang Zongyao
2003-01-01
The expert knowledge library for Daya Bay and Qinshan phase II NPP has been established based on expert knowledge, and the reload core loading pattern heuristic search is performed. The in-core fuel management code system INCORE that has been used in engineering design is employed for neutron calculation, and loading pattern is evaluated by using of cycle length and core radial power peaking factor. The developed system SEDRIO/INCORE has been applied in cycle 4 for unit 2 of Daya Bay NPP and cycle 4 for Phase II in Qinshan NPP. The application demonstrated that the loading patterns obtained by SEDRIO/INCORE system are much better than reference ones from the view of the radial power peak and the cycle length
Shan, Jia
As its role in satisfying the energy demand of the U.S. and as a clean fuel has become more significant than ever, the shale gas production in the U.S. has gained increasing momentum over recent years. Thus, effective and environmentally friendly methods to extract shale gas are critical. Hydraulic fracturing has been proven to be efficient in the production of shale gas. However, environmental issues such as underground water contamination and high usage of water make this technology controversial. A potential technology to eliminate the environmental issues concerning water usage and contamination is to use blast fracturing, which uses explosives to create fractures. It can be further aided by HEGF and multi-pulse pressure loading technology, which causes less crushing effect near the wellbore and induces longer fractures. Radial drilling is another relatively new technology that can bypass damage zones due to drilling and create a larger drainage area through drilling horizontal wellbores. Blast fracturing and radial drilling both have the advantage of cost saving. The successful combination of blast fracturing and radial drilling has a great potential for improving U.S. shale gas production. An analytical productivity model was built in this study, considering linear flow from the reservoir rock to the fracture face, to analyze factors affecting shale gas production from radial lateral wells with shockwave completion. Based on the model analyses, the number of fractures per lateral is concluded to be the most effective factor controlling the productivity index of blast-fractured radial lateral wells. This model can be used for feasibility studies of replacing hydraulic fracturing by blast fracturing in shale gas well completions. Prediction of fracture geometry is recommended for future studies.
Radial pseudoaneurysm following diagnostic coronary angiography
Directory of Open Access Journals (Sweden)
Shankar Laudari
2015-06-01
Full Text Available The radial artery access has gained popularity as a method of diagnostic coronary catheterization compared to femoral artery puncture in terms of vascular complications and early ambulation. However, very rare complication like radial artery pseudoaneurysm may occur following cardiac catheterization which may give rise to serious consequences. Here, we report a patient with radial pseudoaneurysm following diagnostic coronary angiography. Adequate and correct methodology of compression of radial artery following puncture for maintaining hemostasis is the key to prevention.DOI: http://dx.doi.org/10.3126/jcmsn.v10i3.12776 Journal of College of Medical Sciences-Nepal, 2014, Vol-10, No-3, 48-50
DeWitt, John; Schaffner, Grant; Laughlin, Mitzi; Loehr, James; Hagan, R. Donald
2004-01-01
Long-term exposure to microgravity induces detrimefits to the musculcskdetal system (Schneider et al., 1995; LeBlanc et al., 2000). Treadmill exercise is used onboard the International Space Station as an exercise countermeasure to musculoskeletal deconditioning due to spaceflight. During locomotive exercise in weightlessness (0G), crewmembers wear a harness attached to an external loading mechanism (EL). The EL pulls the crewmember toward the treadmill, and provides resistive load during the impact and propulsive phases of gait. The resulting forces may be important in stimulating bone maintenance (Turner, 1998). The EL can be applied via a bungee and carabineer clip configuration attached to the harness and can be manipulated to create varying amounts of load levels during exercise. Ground-based research performed using a vertically mounted treadmill found that peak ground reaction forces (GRF) during running at an EL of less than one body weight (BW) are less than those that occur during running in normal gravity (1G) (Davis et al., 1996). However, it is not known how the GRF are affected by the EL in a true OG environment. Locomotion while suspended may result in biomechanics that differ from free running. The purpose of this investigation was to determine how EL affects peak impact force, peak propulsive force, loading rate, and impulse of the GRF during running in 0G. It was hypothesized that increasing EL would result in increases in each GRF parameter.
DEFF Research Database (Denmark)
Carranza, Christian L; Ballegaard, Martin; Werner, Mads U
2014-01-01
the postoperative complications will be registered, and we will evaluate muscular function, scar appearance, vascular supply to the hand, and the graft patency including the patency of the central radial artery anastomosis. A patency evaluation by multi-slice computer tomography will be done at one year...... to aorto-radial revascularisation techniques but this objective is exploratory. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01848886.Danish Ethics committee number: H-3-2012-116.Danish Data Protection Agency: 2007-58-0015/jr.n:30-0838....
Evaluation of Reinforced Concrete Structural Members under Uniform Loads Using Truss Model
Directory of Open Access Journals (Sweden)
Houshang Dabbagh
2016-03-01
Full Text Available Truss model is an analytical approach to predict the strength of reinforced concrete members with geometric or statical discontinuous regions. This study investigates the use of truss model to predict the structural behavior of reinforced concrete members with discontinuity areas under monotonic loading. The estimated failure load and its corresponding deformation are the main objective of this research. Twenty and three samples including short shear walls, short columns and deep beams tested by other researchers throughout the literature have been selected. Then their truss models as well as their three dimensional finite element models are analyzed using ABAQUS software. The comparison of experimental and analytical results shows fair correlation between them. Also, the structural response of samples estimated by truss model analysis is fairly acceptable.
Numerical simulation of liquid-metal-flows in radial-toroidal-radial bends
International Nuclear Information System (INIS)
Molokov, S.; Buehler, L.
1993-09-01
Magnetohydrodynamic flows in a U-bend and right-angle bend are considered with reference to the radial-toroidal-radial concept of a self-cooled liquid-metal blanket. The ducts composing bends have rectangular cross-section. The applied magnetic field is aligned with the toroidal duct and perpendicular to the radial ones. At high Hartmann number the flow region is divided into cores and boundary layers of different types. The magnetohydrodynamic equations are reduced to a system of partial differential equations governing wall electric potentials and the core pressure. The system is solved numerically by two different methods. The first method is iterative with iteration between wall potential and the core pressure. The second method is a general one for the solution of the core flow equations in curvilinear coordinates generated by channel geometry and magnetic field orientation. Results obtained are in good agreement. They show, that the 3D-pressure drop of MHD flows in a U-bend is not a critical issue for blanket applications. (orig./HP) [de
International Nuclear Information System (INIS)
Vasina, P; Hytkova, T; Elias, M
2009-01-01
The majority of current models of the reactive magnetron sputtering assume a uniform shape of the discharge current density and the same temperature near the target and the substrate. However, in the real experimental set-up, the presence of the magnetic field causes high density plasma to form in front of the cathode in the shape of a toroid. Consequently, the discharge current density is laterally non-uniform. In addition to this, the heating of the background gas by sputtered particles, which is usually referred to as the gas rarefaction, plays an important role. This paper presents an extended model of the reactive magnetron sputtering that assumes the non-uniform discharge current density and which accommodates the gas rarefaction effect. It is devoted mainly to the study of the behaviour of the reactive sputtering rather that to the prediction of the coating properties. Outputs of this model are compared with those that assume uniform discharge current density and uniform temperature profile in the deposition chamber. Particular attention is paid to the modelling of the radial variation of the target composition near transitions from the metallic to the compound mode and vice versa. A study of the target utilization in the metallic and compound mode is performed for two different discharge current density profiles corresponding to typical two pole and multipole magnetics available on the market now. Different shapes of the discharge current density were tested. Finally, hysteresis curves are plotted for various temperature conditions in the reactor.
Integration of a hydraulic production plant in a weak power system on a long radial line
Energy Technology Data Exchange (ETDEWEB)
Lariviere, P. [Hydro-Quebec TransEnergie, 5655 de Marseille, Montreal, Quebec (Canada); Racine, M. [Hydro-Quebec TransEnergie, C.P. 10 000, Montreal, Quebec (Canada)
2009-03-15
Integrating power plants on long lines and weak power systems requires some care. To this effect, a study was conducted to determine if severe disturbances could result when a hydraulic production plant is integrated along a very long radial transmission line. Frequency responses were evaluated to identify possible resonant system operating conditions. Many events such as faults, transformer energyzing and line opening were investigated. All power plant synchronous machines were represented including exciter and governor regulators. Impact of dynamic modeling of the load was examined. The study demonstrates that the overall protective strategy implemented will limit worst overvoltage constraints imposed to equipment and load within an acceptable level. (author)
Experimental study on gas-puff Z-pinch load characteristics on yang accelerator
International Nuclear Information System (INIS)
Ren Xiaodong; Huang Xianbin; Yang Libing; Dan Jiakun; Duan Shuchao; Zhang Zhaohui; Zhou Shaotong
2010-01-01
A supersonic single-shell gas-puff load has been developed for Z-pinch experiments on 'Yang' accelerator. Using a fast responding pressure probe to measure the supersonic gas flow, impact pressure at different position and plenum pressure were acquired, which were combined with gas dynamics formulas to determine gas pressures and densities. The radial density profile displays that positions of gas shell varies with axial position, and the gas densities on axis increases as the distance from nozzle increases. Integral radial densities indicates that the linear mass density peaks at nozzle exit and decreases as increasing the distance from nozzle. Using single-shell supersonic gas-puff load, Z-pinch implosion experiments were performed on 'Yang' accelerator. Primary analysis of implosion process was presented, and computational trajectories of imploding plasma shell using snowplow model are in agreement with the experimental results. (authors)
Dedicated radial ventriculography pigtail catheter
Energy Technology Data Exchange (ETDEWEB)
Vidovich, Mladen I., E-mail: miv@uic.edu
2013-05-15
A new dedicated cardiac ventriculography catheter was specifically designed for radial and upper arm arterial access approach. Two catheter configurations have been developed to facilitate retrograde crossing of the aortic valve and to conform to various subclavian, ascending aortic and left ventricular anatomies. The “short” dedicated radial ventriculography catheter is suited for horizontal ascending aortas, obese body habitus, short stature and small ventricular cavities. The “long” dedicated radial ventriculography catheter is suited for vertical ascending aortas, thin body habitus, tall stature and larger ventricular cavities. This new design allows for improved performance, faster and simpler insertion in the left ventricle which can reduce procedure time, radiation exposure and propensity for radial artery spasm due to excessive catheter manipulation. Two different catheter configurations allow for optimal catheter selection in a broad range of patient anatomies. The catheter is exceptionally stable during contrast power injection and provides equivalent cavity opacification to traditional femoral ventriculography catheter designs.
Limit load assessment of centre cracked plates under biaxial loading
International Nuclear Information System (INIS)
Meek, C.; Ainsworth, R.A.
2015-01-01
Fitness-for-service of equipment and components containing defects is generally assessed using procedures such as BS 7910, API 579 and R6. There is currently little detailed advice in these procedures on the effects of biaxial and triaxial loading on fracture. This poster shows some theoretical bounding solutions of the plastic limit load for centre cracked plates under a variety of biaxial loading ratios and compares the estimates with those found by numerical methods using finite element (FE) analysis using Abacus CAE modelling software. The limit load of a structure is the maximum load that it can carry before plastic collapse occurs; this is often when the plastic zone has become large enough to spread from the crack tip to a remote boundary. For an elastic-perfectly plastic material, the irreversible deformation will continue at stresses no higher than the yield stress. The model for these limit load solutions is a bi-axially loaded plate of width 2W and height 2H, a centre crack of width 2a, acted on by remotely applied uniform stresses σ 2 perpendicular to the crack and Bσ 2 parallel to the crack, where B is the biaxial loading ratio, it means the ratio of the parallel to the perpendicular stress. A quarter plate of an elastic-perfectly plastic material has been modelled. The results show that an exact solution has been found for negative and low positive values of B. For B > 1, the lower bound solution is conservative for all values of a/W and B
Torrent, Daniel; Sánchez-Dehesa, José
2009-08-07
We demonstrate that metamaterials with anisotropic properties can be used to develop a new class of periodic structures that has been named radial wave crystals. They can be sonic or photonic, and wave propagation along the radial directions is obtained through Bloch states like in usual sonic or photonic crystals. The band structure of the proposed structures can be tailored in a large amount to get exciting novel wave phenomena. For example, it is shown that acoustical cavities based on radial sonic crystals can be employed as passive devices for beam forming or dynamically orientated antennas for sound localization.
Intelligent harmonic load model based on neural networks
Ji, Pyeong-Shik; Lee, Dae-Jong; Lee, Jong-Pil; Park, Jae-Won; Lim, Jae-Yoon
2007-12-01
In this study, we developed a RBFNs(Radial Basis Function Networks) based load modeling method with harmonic components. The developed method implemented by using harmonic information as well as fundamental frequency and voltage which are essential input factors in conventional method. Thus, the proposed method makes it possible to effectively estimate load characteristics in power lines with harmonics. The RBFNs have certain advantage such as simple structure and rapid computation ability compared with multilayer perceptron which is extensively applied for load modeling. To show the effectiveness, the proposed method has been intensively tested with various dataset acquired under the different frequency and voltage and compared it with conventional methods such as polynominal 2nd equation method, MLP and RBF without considering harmonic components.
Directory of Open Access Journals (Sweden)
Luiz Ernani Meira Jr.
2011-12-01
Full Text Available Os aneurismas da artéria radial são extremamente raros. Em sua maioria, consistem de pseudoaneurismas pós-traumáticos. Os aneurismas da artéria radial verdadeiros podem ser idiopáticos, congênitos, pós-estenóticos ou associados a patologias, tais como vasculites e doenças do tecido conjuntivo. Foi relatado um caso de aneurisma idiopático de artéria radial em uma criança de três anos, que, após completa investigação diagnóstica complementar, foi submetida à ressecção cirúrgica.Radial artery aneurysms are extremely rare. Post-traumatic pseudoaneurysms are the vast majority. True radial artery aneurysms can be idiopathic, congenital, poststenotic, or associated with some pathologies, such as vasculitis and conjunctive tissue diseases. We report a case of an idiopathic aneurysm of the radial artery in a three-year-old child who was submitted to surgical resection after a complete diagnostic approach.
Analysis of VAWT aerodynamics and design using the Actuator Cylinder flow model
DEFF Research Database (Denmark)
Aagaard Madsen, Helge; Schmidt Paulsen, Uwe; Vita, Luca
2014-01-01
The actuator cylinder (AC) flow model is defined as the ideal VAWT rotor. Radial directed volume forces are applied on the circular path of the VAWT rotor airfoil and constitute an energy conversion in the flow. The power coefficient for the ideal as well as the real energy conversion is defined....... obtainable power coefficient for a fixed pitch VAWT is constrained by the fundamental cyclic variation of inflow angle and relative velocity leading to a loading that deviates considerably from the uniform loading.......The actuator cylinder (AC) flow model is defined as the ideal VAWT rotor. Radial directed volume forces are applied on the circular path of the VAWT rotor airfoil and constitute an energy conversion in the flow. The power coefficient for the ideal as well as the real energy conversion is defined....... The describing equations for the two-dimensional AC model are presented and a solution method splitting the final solution in a linear and non-linear part is briefly described. A family of loadforms approaching the uniform loading is used to study the ideal energy conversion indicating that the maximum power...
Ulnar nerve entrapment complicating radial head excision
Directory of Open Access Journals (Sweden)
Kevin Parfait Bienvenu Bouhelo-Pam
Full Text Available Introduction: Several mechanisms are involved in ischemia or mechanical compression of ulnar nerve at the elbow. Presentation of case: We hereby present the case of a road accident victim, who received a radial head excision for an isolated fracture of the radial head and complicated by onset of cubital tunnel syndrome. This outcome could be the consequence of an iatrogenic valgus of the elbow due to excision of the radial head. Hitherto the surgical treatment of choice it is gradually been abandoned due to development of radial head implant arthroplasty. However, this management option is still being performed in some rural centers with low resources. Discussion: The radial head plays an important role in the stability of the elbow and his iatrogenic deformity can be complicated by cubital tunnel syndrome. Conclusion: An ulnar nerve release was performed with favorable outcome. Keywords: Cubital tunnel syndrome, Peripheral nerve palsy, Radial head excision, Elbow valgus
Short-Term Load Forecast in Electric Energy System in Bulgaria
Directory of Open Access Journals (Sweden)
Irina Asenova
2010-01-01
Full Text Available As the accuracy of the electricity load forecast is crucial in providing better cost effective risk management plans, this paper proposes a Short Term Electricity Load Forecast (STLF model with high forecasting accuracy. Two kind of neural networks, Multilayer Perceptron network model and Radial Basis Function network model, are presented and compared using the mean absolute percentage error. The data used in the models are electricity load historical data. Even though the very good performance of the used model for the load data, weather parameters, especially the temperature, take important part for the energy predicting which is taken into account in this paper. A comparative evaluation between a traditional statistical method and artificial neural networks is presented.
Radial collapse and physical mechanism of carbon nanotube with divacancy and 5-8-5 defects
International Nuclear Information System (INIS)
Zhang Ya-Ping; Ling Cui-Cui; Li Gui-Xia; Zhu Hai-Feng; Zhang Meng-Yu
2015-01-01
By employing molecular mechanics and molecular dynamics simulations, we investigate the radial collapses and elasticities of different chiral single-walled carbon nanotubes (SWCNTs) with divacancy, and 5-8-5 defects. It is found that divacancy and 5-8-5 defect can reduce the collapse pressure (P c ) of SWCNT (10, 10) while 5-8-5 defect can greatly increase P c of SWCNT (17, 0). For example, 5-8-5 defect can make P c of SWCNT (17, 0) increase by 500%. A model is established to understand the effects of chirality, divacancy, and 5-8-5 defect on radial collapse of SWCNTs. The results are particularly of value for understanding the mechanical behavior of SWCNT with divacancy, and the 5-8-5 defect that may be considered as a filler of high loading composites. (paper)
Radial lean direct injection burner
Khan, Abdul Rafey; Kraemer, Gilbert Otto; Stevenson, Christian Xavier
2012-09-04
A burner for use in a gas turbine engine includes a burner tube having an inlet end and an outlet end; a plurality of air passages extending axially in the burner tube configured to convey air flows from the inlet end to the outlet end; a plurality of fuel passages extending axially along the burner tube and spaced around the plurality of air passage configured to convey fuel from the inlet end to the outlet end; and a radial air swirler provided at the outlet end configured to direct the air flows radially toward the outlet end and impart swirl to the air flows. The radial air swirler includes a plurality of vanes to direct and swirl the air flows and an end plate. The end plate includes a plurality of fuel injection holes to inject the fuel radially into the swirling air flows. A method of mixing air and fuel in a burner of a gas turbine is also provided. The burner includes a burner tube including an inlet end, an outlet end, a plurality of axial air passages, and a plurality of axial fuel passages. The method includes introducing an air flow into the air passages at the inlet end; introducing a fuel into fuel passages; swirling the air flow at the outlet end; and radially injecting the fuel into the swirling air flow.
Apparatus for blending small particles
International Nuclear Information System (INIS)
Bradley, R.A.; Reese, C.R.; Sease, J.D.
1975-01-01
An apparatus is described for blending small particles and uniformly loading the blended particles in a receptacle. Measured volumes of various particles are simultaneously fed into a funnel to accomplish radial blending and then directed onto the apex of a conical splitter which collects the blended particles in a multiplicity of equal subvolumes. Thereafter the apparatus sequentially discharges the subvolumes for loading in a receptacle. A system for blending nuclear fuel particles and loading them into fuel rod molds is described in a preferred embodiment
Experimental analysis on the dynamic wake of an actuator disc undergoing transient loads
Yu, W.; Hong, V. W.; Ferreira, C.; van Kuik, G. A. M.
2017-10-01
The Blade Element Momentum model, which is based on the actuator disc theory, is still the model most used for the design of open rotors. Although derived from steady cases with a fully developed wake, this approach is also applied to unsteady cases, with additional engineering corrections. This work aims to study the impact of an unsteady loading on the wake of an actuator disc. The load and flow of an actuator disc are measured in the Open Jet Facility wind tunnel of Delft University of Technology, for steady and unsteady cases. The velocity and turbulence profiles are characterized in three regions: the inner wake region, the shear layer region and the region outside the wake. For unsteady load cases, the measured velocity field shows a hysteresis effect in relation to the loading, showing differences between the cases when loading is increased and loading is decreased. The flow field also shows a transient response to the step change in loading, with either an overshoot or undershoot of the velocity in relation to the steady-state velocity. In general, a smaller reduced ramp time results in a faster velocity transient, and in turn a larger amplitude of overshoot or undershoot. Time constants analysis shows that the flow reaches the new steady-state slower for load increase than for load decrease; the time constants outside the wake are generally larger than at other radial locations for a given downstream plane; the time constants of measured velocity in the wake show radial dependence.The data are relevant for the validation of numerical models for unsteady actuator discs and wind turbines, and are made available in an open source database (see Appendix).
Cell-centered particle weighting algorithm for PIC simulations in a non-uniform 2D axisymmetric mesh
Araki, Samuel J.; Wirz, Richard E.
2014-09-01
Standard area weighting methods for particle-in-cell simulations result in systematic errors on particle densities for a non-uniform mesh in cylindrical coordinates. These errors can be significantly reduced by using weighted cell volumes for density calculations. A detailed description on the corrected volume calculations and cell-centered weighting algorithm in a non-uniform mesh is provided. The simple formulas for the corrected volume can be used for any type of quadrilateral and/or triangular mesh in cylindrical coordinates. Density errors arising from the cell-centered weighting algorithm are computed for radial density profiles of uniform, linearly decreasing, and Bessel function in an adaptive Cartesian mesh and an unstructured mesh. For all the density profiles, it is shown that the weighting algorithm provides a significant improvement for density calculations. However, relatively large density errors may persist at outermost cells for monotonically decreasing density profiles. A further analysis has been performed to investigate the effect of the density errors in potential calculations, and it is shown that the error at the outermost cell does not propagate into the potential solution for the density profiles investigated.
Anomalies of radial and ulnar arteries
Directory of Open Access Journals (Sweden)
Rajani Singh
Full Text Available Abstract During dissection conducted in an anatomy department of the right upper limb of the cadaver of a 70-year-old male, both origin and course of the radial and ulnar arteries were found to be anomalous. After descending 5.5 cm from the lower border of the teres major, the brachial artery anomalously bifurcated into a radial artery medially and an ulnar artery laterally. In the arm, the ulnar artery lay lateral to the median nerve. It followed a normal course in the forearm. The radial artery was medial to the median nerve in the arm and then, at the level of the medial epicondyle, it crossed from the medial to the lateral side of the forearm, superficial to the flexor muscles. The course of the radial artery was superficial and tortuous throughout the arm and forearm. The variations of radial and ulnar arteries described above were associated with anomalous formation and course of the median nerve in the arm. Knowledge of neurovascular anomalies are important for vascular surgeons and radiologists.
LENUS (Irish Health Repository)
Pate, G
2011-10-01
A survey was conducted of medication administered during radial artery cannulation for coronary angiography in 2009 in Ireland; responses were obtained for 15 of 20 centres, in 5 of which no radial access procedures were undertaken. All 10 (100%) centres which provided data used heparin and one or more anti-spasmodics; verapamil in 9 (90%), nitrate in 1 (10%), both in 2 (20%). There were significant variations in the doses used. Further work needs to be done to determine the optimum cocktail to prevent radial artery injury following coronary angiography.
Uniformity testing: assessment of a centralized web-based uniformity analysis system.
Klempa, Meaghan C
2011-06-01
Uniformity testing is performed daily to ensure adequate camera performance before clinical use. The aim of this study is to assess the reliability of Beth Israel Deaconess Medical Center's locally built, centralized, Web-based uniformity analysis system by examining the differences between manufacturer and Web-based National Electrical Manufacturers Association integral uniformity calculations measured in the useful field of view (FOV) and the central FOV. Manufacturer and Web-based integral uniformity calculations measured in the useful FOV and the central FOV were recorded over a 30-d period for 4 cameras from 3 different manufacturers. These data were then statistically analyzed. The differences between the uniformity calculations were computed, in addition to the means and the SDs of these differences for each head of each camera. There was a correlation between the manufacturer and Web-based integral uniformity calculations in the useful FOV and the central FOV over the 30-d period. The average differences between the manufacturer and Web-based useful FOV calculations ranged from -0.30 to 0.099, with SD ranging from 0.092 to 0.32. For the central FOV calculations, the average differences ranged from -0.163 to 0.055, with SD ranging from 0.074 to 0.24. Most of the uniformity calculations computed by this centralized Web-based uniformity analysis system are comparable to the manufacturers' calculations, suggesting that this system is reasonably reliable and effective. This finding is important because centralized Web-based uniformity analysis systems are advantageous in that they test camera performance in the same manner regardless of the manufacturer.
Design of radial reinforcement for prestressed concrete containments
Energy Technology Data Exchange (ETDEWEB)
Wang, Shen, E-mail: swang@bechtel.com [Bechtel Power Corporation, 5275 Westview Drive, BP2-2C3, Frederick, MD 21703 (United States); Munshi, Javeed A., E-mail: jamunshi@bechtel.com [Bechtel Power Corporation, 5275 Westview Drive, BP2-2C3, Frederick, MD 21703 (United States)
2013-02-15
Highlights: ► A rigorous formulae is proposed to calculate radial stress within prestressed concrete containments. ► The proposed method is validated by finite element analysis in an illustrative practical example. ► A partially prestressed condition is more critical than a fully prestressed condition for radial tension. ► Practical design consideration is provided for detailing of radial reinforcement. -- Abstract: Nuclear containments are critical components for safety of nuclear power plants. Failure can result in catastrophic safety consequences as a result of leakage of radiation. Prestressed concrete containments have been used in large nuclear power plants with significant design internal pressure. These containments are generally reinforced with prestressing tendons in the circumferential (hoop) and meridional (vertical) directions. The curvature effect of the tendons introduces radial tensile stresses in the concrete shell which are generally neglected in the design of such structures. It is assumed that such tensile radial stresses are small as such no radial reinforcement is provided for this purpose. But recent instances of significant delaminations in Crystal River Unit 3 in Florida have elevated the need for reevaluation of the radial tension issue in prestressed containment. Note that currently there are no well accepted industry standards for design and detailing of radial reinforcement. This paper discusses the issue of radial tension in prestressed cylindrical and dome shaped structures and proposes formulae to calculate radial stresses. A practical example is presented to illustrate the use of the proposed method which is then verified by using state of art finite element analysis. This paper also provides some practical design consideration for detailing of radial reinforcement in prestressed containments.
Methods and apparatus for radially compliant component mounting
Bulman, David Edward [Cincinnati, OH; Darkins, Jr., Toby George; Stumpf, James Anthony [Columbus, IN; Schroder, Mark S [Greenville, SC; Lipinski, John Joseph [Simpsonville, SC
2012-03-27
Methods and apparatus for a mounting assembly for a liner of a gas turbine engine combustor are provided. The combustor includes a combustor liner and a radially outer annular flow sleeve. The mounting assembly includes an inner ring surrounding a radially outer surface of the liner and including a plurality of axially extending fingers. The mounting assembly also includes a radially outer ring coupled to the inner ring through a plurality of spacers that extend radially from a radially outer surface of the inner ring to the outer ring.
Cohn, Carl A.
1996-01-01
Shortly after implementing a mandatory school uniform policy, the Long Beach (California) Public Schools can boast 99% compliance and a substantial reduction in school crime. The uniforms can't be confused with gang colors, save parents money, and help identify outsiders. A sidebar lists ingredients for a mandatory uniform policy. (MLH)
Dynamic Load on a Pipe Caused by Acetylene Detonations – Experiments and Theoretical Approaches
Directory of Open Access Journals (Sweden)
Axel Sperber
1999-01-01
Full Text Available The load acting on the wall of a pipe by a detonation, which is travelling through, is not yet well characterized. The main reasons are the limited amount of sufficiently accurate pressure time history data and the requirement of considering the dynamics of the system. Laser vibrometry measurements were performed to determine the dynamic response of the pipe wall on a detonation. Different modelling approaches were used to quantify, theoretically, the radial displacements of the pipe wall. There is good agreement between measured and predicted values of vibration frequencies and the propagation velocities of transverse waves. Discrepancies mainly due to wave propagation effects were found in the amplitudes of the radial velocities. They might be overcome by the use of a dynamic load factor or improved modelling methods.
Load bearing capacities and elastic-plastic behavior of reactor vessel internals
International Nuclear Information System (INIS)
Watanabe, Keita; Nagase, Ryuichi
2017-01-01
Radial Support Keys (RSKs) are installed at the bottom of Reactor Vessel Internal (RVI) of Pressurized Water Reactor (PWR) and fit into Core Support Lugs of Reactor Pressure Vessel (RPV). This structure provides reactor core horizontal support and transmits the loads between RVI and RPV. RSK is one of the critical parts of RVI from the view point of earthquake-proof safety. In order to assure the structural integrity of Nuclear Reactor in case of massive earthquake, load bearing capacities of RSK are confirmed by static loading tests with reduced-scale mockups. In addition, collapse loads of actual components calculated by Limit Analyses are conservative enough compared to the load bearing capacities confirmed by the test. Thus, the methodology to calculate collapse load by Limit Analysis is applicable to evaluation of structural integrity for RSK. (author)
Computer model analysis of the radial artery pressure waveform.
Schwid, H A; Taylor, L A; Smith, N T
1987-10-01
Simultaneous measurements of aortic and radial artery pressures are reviewed, and a model of the cardiovascular system is presented. The model is based on resonant networks for the aorta and axillo-brachial-radial arterial system. The model chosen is a simple one, in order to make interpretation of the observed relationships clear. Despite its simplicity, the model produces realistic aortic and radial artery pressure waveforms. It demonstrates that the resonant properties of the arterial wall significantly alter the pressure waveform as it is propagated from the aorta to the radial artery. Although the mean and end-diastolic radial pressures are usually accurate estimates of the corresponding aortic pressures, the systolic pressure at the radial artery is often much higher than that of the aorta due to overshoot caused by the resonant behavior of the radial artery. The radial artery dicrotic notch is predominantly dependent on the axillo-brachial-radial arterial wall properties, rather than on the aortic valve or peripheral resistance. Hence the use of the radial artery dicrotic notch as an estimate of end systole is unreliable. The rate of systolic upstroke, dP/dt, of the radial artery waveform is a function of many factors, making it difficult to interpret. The radial artery waveform usually provides accurate estimates for mean and diastolic aortic pressures; for all other measurements it is an inadequate substitute for the aortic pressure waveform. In the presence of low forearm peripheral resistance the mean radial artery pressure may significantly underestimate the mean aortic pressure, as explained by a voltage divider model.
Dowling-Sendor, Benjamin
2002-01-01
Reviews a recent decision in "Littlefield" by the 5th Circuit upholding a school uniform policy. Advises board member who wish to adopt a school uniform policy to solicit input from parents and students, research the experiences of other school districts with uniform policies, and articulate the interests they wish to promote through uniform…
2016-05-20
Hershaw Thesis submitted to the Faculty of the Medical Psychology Graduate Program Uniformed Services University of the Health ...system while completing a task. The amount of mental effort and cognitive resources required to complete a task depends on cognitive load. Thus, the...load and require greater mental effort for people with mild TBI. PUPILLOMETRIC ASSESSMENT OF COGNITIVE LOAD Differences in cognitive load in
Stochastic Evaluation of Maximum Wind Installation in a Radial Distribution Network
DEFF Research Database (Denmark)
Chen, Peiyuan; Bak-Jensen, Birgitte; Chen, Zhe
2011-01-01
This paper proposes an optimization algorithm to find the maximum wind installation in a radial distribution network. The algorithm imposes a limit on the amount of wind energy that can be curtailed annually. The algorithm implements the wind turbine reactive power control and wind energy...... curtailment using sensitivity factors. The optimization is integrated with Monte Carlo simulation to account for the stochastic behavior of load demand and wind power generation. The proposed algorithm is tested on a real 20 kV Danish distribution system in Støvring. It is demonstrated that the algorithm...... executes reactive compensation and energy curtailment sequentially in an effective and efficient manner....
Sasaki, Youhei; Takehiro, Shin-ichi; Ishiwatari, Masaki; Yamada, Michio
2018-03-01
Linear stability analysis of anelastic thermal convection in a rotating spherical shell with entropy diffusivities varying in the radial direction is performed. The structures of critical convection are obtained in the cases of four different radial distributions of entropy diffusivity; (1) κ is constant, (2) κT0 is constant, (3) κρ0 is constant, and (4) κρ0T0 is constant, where κ is the entropy diffusivity, T0 is the temperature of basic state, and ρ0 is the density of basic state, respectively. The ratio of inner and outer radii, the Prandtl number, the polytropic index, and the density ratio are 0.35, 1, 2, and 5, respectively. The value of the Ekman number is 10-3 or 10-5 . In the case of (1), where the setup is same as that of the anelastic dynamo benchmark (Jones et al., 2011), the structure of critical convection is concentrated near the outer boundary of the spherical shell around the equator. However, in the cases of (2), (3) and (4), the convection columns attach the inner boundary of the spherical shell. A rapidly rotating annulus model for anelastic systems is developed by assuming that convection structure is uniform in the axial direction taking into account the strong effect of Coriolis force. The annulus model well explains the characteristics of critical convection obtained numerically, such as critical azimuthal wavenumber, frequency, Rayleigh number, and the cylindrically radial location of convection columns. The radial distribution of entropy diffusivity, or more generally, diffusion properties in the entropy equation, is important for convection structure, because it determines the distribution of radial basic entropy gradient which is crucial for location of convection columns.
MR accuracy and arthroscopic incidence of meniscal radial tears
Energy Technology Data Exchange (ETDEWEB)
Magee, Thomas; Shapiro, Marc; Williams, David [Department of Radiology, Neuroimaging Institute, 27 East Hibiscus Blvd., Melbourne, FL 32901 (United States)
2002-12-01
A meniscal radial tear is a vertical tear that involves the inner meniscal margin. The tear is most frequent in the middle third of the lateral meniscus and may extend outward in any direction. We report (1) the arthroscopic incidence of radial tears, (2) MR signs that aid in the detection of radial tears and (3) our prospective accuracy in detection of radial tears. Design and patients. Three musculoskeletal radiologists prospectively read 200 consecutive MR examinations of the knee that went on to arthroscopy by one orthopedic surgeon. MR images were assessed for location and MR characteristics of radial tears. MR criteria used for diagnosis of a radial tear were those outlined by Tuckman et al.: truncation, abnormal morphology and/or lack of continuity or absence of the meniscus on one or more MR images. An additional criterion used was abnormal increased signal in that area on fat-saturated proton density or T2-weighted coronal and sagittal images. Prospective MR readings were correlated with the arthroscopic findings.Results. Of the 200 consecutive knee arthroscopies, 28 patients had radial tears reported arthroscopically (14% incidence). MR readings prospectively demonstrated 19 of the 28 radial tears (68% sensitivity) when the criteria for diagnosis of a radial tear were truncation or abnormal morphology of the meniscus. With the use of the additional criterion of increased signal in the area of abnormal morphology on fat-saturated T2-weighted or proton density weighted sequences, the prospective sensitivity was 25 of 28 radial tears (89% sensitivity). There were no radial tears described in MR reports that were not demonstrated on arthroscopy (i.e., there were no false positive MR readings of radial tears in these 200 patients). Radial tears are commonly seen at arthroscopy. There was a 14% incidence in this series of 200 patients who underwent arthroscopy. Prospective detection of radial tears was 68% as compared with arthroscopy when the criteria as
MR accuracy and arthroscopic incidence of meniscal radial tears
International Nuclear Information System (INIS)
Magee, Thomas; Shapiro, Marc; Williams, David
2002-01-01
A meniscal radial tear is a vertical tear that involves the inner meniscal margin. The tear is most frequent in the middle third of the lateral meniscus and may extend outward in any direction. We report (1) the arthroscopic incidence of radial tears, (2) MR signs that aid in the detection of radial tears and (3) our prospective accuracy in detection of radial tears. Design and patients. Three musculoskeletal radiologists prospectively read 200 consecutive MR examinations of the knee that went on to arthroscopy by one orthopedic surgeon. MR images were assessed for location and MR characteristics of radial tears. MR criteria used for diagnosis of a radial tear were those outlined by Tuckman et al.: truncation, abnormal morphology and/or lack of continuity or absence of the meniscus on one or more MR images. An additional criterion used was abnormal increased signal in that area on fat-saturated proton density or T2-weighted coronal and sagittal images. Prospective MR readings were correlated with the arthroscopic findings.Results. Of the 200 consecutive knee arthroscopies, 28 patients had radial tears reported arthroscopically (14% incidence). MR readings prospectively demonstrated 19 of the 28 radial tears (68% sensitivity) when the criteria for diagnosis of a radial tear were truncation or abnormal morphology of the meniscus. With the use of the additional criterion of increased signal in the area of abnormal morphology on fat-saturated T2-weighted or proton density weighted sequences, the prospective sensitivity was 25 of 28 radial tears (89% sensitivity). There were no radial tears described in MR reports that were not demonstrated on arthroscopy (i.e., there were no false positive MR readings of radial tears in these 200 patients). Radial tears are commonly seen at arthroscopy. There was a 14% incidence in this series of 200 patients who underwent arthroscopy. Prospective detection of radial tears was 68% as compared with arthroscopy when the criteria as
High-voltage electrode optimization towards uniform surface treatment by a pulsed volume discharge
International Nuclear Information System (INIS)
Ponomarev, A V; Pedos, M S; Scherbinin, S V; Mamontov, Y I; Ponomarev, S V
2015-01-01
In this study, the shape and material of the high-voltage electrode of an atmospheric pressure plasma generation system were optimised. The research was performed with the goal of achieving maximum uniformity of plasma treatment of the surface of the low-voltage electrode with a diameter of 100 mm. In order to generate low-temperature plasma with the volume of roughly 1 cubic decimetre, a pulsed volume discharge was used initiated with a corona discharge. The uniformity of the plasma in the region of the low-voltage electrode was assessed using a system for measuring the distribution of discharge current density. The system's low-voltage electrode - collector - was a disc of 100 mm in diameter, the conducting surface of which was divided into 64 radially located segments of equal surface area. The current at each segment was registered by a high-speed measuring system controlled by an ARM™-based 32-bit microcontroller. To facilitate the interpretation of results obtained, a computer program was developed to visualise the results. The program provides a 3D image of the current density distribution on the surface of the low-voltage electrode. Based on the results obtained an optimum shape for a high-voltage electrode was determined. Uniformity of the distribution of discharge current density in relation to distance between electrodes was studied. It was proven that the level of non-uniformity of current density distribution depends on the size of the gap between electrodes. Experiments indicated that it is advantageous to use graphite felt VGN-6 (Russian abbreviation) as the material of the high-voltage electrode's emitting surface. (paper)
Fuel loading and homogeneity analysis of HFIR design fuel plates loaded with uranium silicide fuel
International Nuclear Information System (INIS)
Blumenfeld, P.E.
1995-08-01
Twelve nuclear reactor fuel plates were analyzed for fuel loading and fuel loading homogeneity by measuring the attenuation of a collimated X-ray beam as it passed through the plates. The plates were identical to those used by the High Flux Isotope Reactor (HFIR) but were loaded with uranium silicide rather than with HFIR's uranium oxide fuel. Systematic deviations from nominal fuel loading were observed as higher loading near the center of the plates and underloading near the radial edges. These deviations were within those allowed by HFIR specifications. The report begins with a brief background on the thermal-hydraulic uncertainty analysis for the Advanced Neutron Source (ANS) Reactor that motivated a statistical description of fuel loading and homogeneity. The body of the report addresses the homogeneity measurement techniques employed, the numerical correction required to account for a difference in fuel types, and the statistical analysis of the resulting data. This statistical analysis pertains to local variation in fuel loading, as well as to ''hot segment'' analysis of narrow axial regions along the plate and ''hot streak'' analysis, the cumulative effect of hot segment loading variation. The data for all twelve plates were compiled and divided into 20 regions for analysis, with each region represented by a mean and a standard deviation to report percent deviation from nominal fuel loading. The central regions of the plates showed mean values of about +3% deviation, while the edge regions showed mean values of about -7% deviation. The data within these regions roughly approximated random samplings from normal distributions, although the chi-square (χ 2 ) test for goodness of fit to normal distributions was not satisfied
Radial velocities of RR Lyrae stars
International Nuclear Information System (INIS)
Hawley, S.L.; Barnes, T.G. III
1985-01-01
283 spectra of 57 RR Lyrae stars have been obtained using the 2.1-m telescope at McDonald Observatory. Radial velocities were determined using a software cross-correlation technique. New mean radial velocities were determined for 46 of the stars. 11 references
Cantilever arrays with self-aligned nanotips of uniform height
International Nuclear Information System (INIS)
Koelmans, W W; Peters, T; Berenschot, E; De Boer, M J; Siekman, M H; Abelmann, L
2012-01-01
Cantilever arrays are employed to increase the throughput of imaging and manipulation at the nanoscale. We present a fabrication process to construct cantilever arrays with nanotips that show a uniform tip–sample distance. Such uniformity is crucial, because in many applications the cantilevers do not feature individual tip–sample spacing control. Uniform cantilever arrays lead to very similar tip–sample interaction within an array, enable non-contact modes for arrays and give better control over the load force in contact modes. The developed process flow uses a single mask to define both tips and cantilevers. An additional mask is required for the back side etch. The tips are self-aligned in the convex corner at the free end of each cantilever. Although we use standard optical contact lithography, we show that the convex corner can be sharpened to a nanometre scale radius by an isotropic underetch step. The process is robust and wafer-scale. The resonance frequencies of the cantilevers within an array are shown to be highly uniform with a relative standard error of 0.26% or lower. The tip–sample distance within an array of up to ten cantilevers is measured to have a standard error around 10 nm. An imaging demonstration using the AFM shows that all cantilevers in the array have a sharp tip with a radius below 10 nm. The process flow for the cantilever arrays finds application in probe-based nanolithography, probe-based data storage, nanomanufacturing and parallel scanning probe microscopy. (paper)
Feasibility study on silicon doping using high temperature test engineering reactor
International Nuclear Information System (INIS)
Seki, Masaya; Takaki, Naoyuki; Goto, Minoru; Shimakawa, Satoshi
2011-01-01
The feasibility study on silicon doping using the High Temperature engineering Test Reactor (HTTR) is performed by numerical simulations. The HTTR is a High Temperature Gas-cooled Reactor (HTGR) situated at JAEA Oarai research and development center. It has a 30MW thermal power and the outlet coolant temperature is 950degC. The objective of this study is to evaluate the following issues, 1. The impact of loading Si-ingots into the core on the criticality, 2. The uniformity of the neutron capture reaction rate in Si-ingots, and 3. The production rate of silicon semiconductor. In this study, six Si-ingots are loaded into the irradiation area which is located in the peripheral region of the core. They are irradiated with rotation movement around the axial direction to obtain uniform neutron capture reaction rate in the radial direction. Additionally, the neutron filter, which is made of graphite containing boron, is used to obtain uniform neutron capture reaction rate in the axial direction. The evaluations were conducted by performing the HTTR whole core calculations with the Monte Carlo code MVP-2.0. In the calculations, several tally regions were defined on the Si-ingots to investigate the uniformity of the neutron capture reaction rate. As a result, loading the Si-ingots into the core causes negative reactivity by about 0.7%dk/k. Uniform neutron capture reaction rate of Si-ingot is obtained 98% in the radial and the axial direction. In case of the target of semiconductor resistivity is set to 50 Ωcm, the required irradiation time becomes 10 hours. The HTTR is able to produce silicon semiconductor of 540kg in one-time irradiation. This study was conducted as a joint research with JAEA, Nuclear Fuel Industries, LTD, Toyota Tsusho Corporation and Tokai University. (author)
Burkhart, Klaus Josef; Mueller, Lars P; Krezdorn, David; Appelmann, Philipp; Prommersberger, Karl J; Sternstein, Werner; Rommens, Pol M
2007-12-01
Open reduction and internal fixation of radial neck fractures can lead to secondary loss of reduction and nonunion due to insufficient stability. Nevertheless, there are only a few biomechanical studies about the stability achieved by different osteosynthesis constructs. Forty-eight formalin-fixed, human proximal radii were divided into 6 groups according to their bone density (measured by dual-energy x-ray absorptiometry). A 2.7-mm gap osteotomy was performed to simulate an unstable radial neck fracture, which was fixed with 3 nonlocking implants: a 2.4-mm T plate, a 2.4-mm blade plate, and 2.0-mm crossed screws, and 3 locking plates: a 2.0-mm LCP T plate, a 2.0-mm 6x2 grid plate, and a 2.0-mm radial head plate. Implants were tested under axial (N/mm) and torsional (Ncm/ degrees ) loads with a servohydraulic materials testing machine. The radial head plate was significantly stiffer than all other implants under axial as well as under torsional loads, with values of 36 N/mm and 13 Ncm/ degrees . The second-stiffest implant was the blade plate, with values of 20 N/mm and 6 Ncm/ degrees . The weakest implants were the 2.0-mm LCP, with values of 6 N/mm and 2 Ncm/ degrees , and the 2.0-mm crossed screws, with values of 18 N/mm and 2 Ncm/ degrees . The 2.4-mm T plate, with values of 14 N/mm and 4 Ncm/ degrees , and the 2.0-mm grid plate, with values of 8 N/mm and 4 Ncm/ degrees came to lie in the midfield. The 2.0-mm angle-stable plates-depending on their design-allow fixation with comparable or even higher stability than the bulky 2.4-mm nonlocking implants and 2.0-mm crossed screws.
International Nuclear Information System (INIS)
Hewes, R.C.; Miller, T.R.
1988-01-01
To profile optimally each portion of the meniscus, the authors use the multiangle, multisection feature of a General Electric SIGNA 1.5-T imager to produce radial images centered on each meniscus. A total of 12-15 sections are imaged at 10 0 -15 0 intervals of each meniscus, yielding perpendicular images of the entire meniscus, comparable with the arthrographic tangential views. The authors review their technique and demonstrate correlation cases between the radial gradient recalled acquisition in a steady state sequences, sagittal and coronal MR images, and arthrograms. Radial images should be a routine part of knee MR imaging
Directory of Open Access Journals (Sweden)
Mukul Dixit
2017-04-01
The various costs such as purchase active power from grid, DG installation, capacitor installation, DG Operation and Maintenance (O&M are evaluated at two different load scenarios. In addition to that, technical and economical analyses are examined for various combinations of DGs and shunt capacitors. The proposed methodology is successfully demonstrated on 33-bus and 85-bus radial networks and the obtained numerical outcomes validate the suitability, importance and effectiveness to identify locations as well as sizes of DGs and shunt capacitors.
21 CFR 866.4800 - Radial immunodiffusion plate.
2010-04-01
...) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Immunology Laboratory Equipment and Reagents § 866.4800 Radial immunodiffusion plate. (a) Identification. A radial immunodiffusion plate for clinical use...
International Nuclear Information System (INIS)
Hobson, G.H.; Turinsky, P.J.
1986-01-01
Computational capability has been developed to automatically determine a good estimate of the core loading pattern, which minimizes fuel cycle costs for a pressurized water reactor (PWR). Equating fuel cycle cost minimization with core reactivity maximization, the objective is to determine the loading pattern that maximizes core reactivity while satisfying power peaking, discharge burnup, and other constraints. The method utilizes a two-dimensional, coarse-mesh, finite difference scheme to evaluate core reactivity and fluxes for an initial reference loading pattern. First-order perturbation theory is applied to determine the effects of assembly shuffling on reactivity, power distribution, end-of-cycle burnup. Monte Carlo integer programming is then used to determine a near-optimal loading pattern within a range of loading patterns near the reference pattern. The process then repeats with the new loading pattern as the reference loading pattern and terminates when no better loading pattern can be determined. The process was applied with both reactivity maximization and radial power-peaking minimization as objectives. Results on a typical large PWR indicate that the cost of obtaining an 8% improvement in radial power-peaking margin is ≅2% in fuel cycle costs, for the reload core loaded without burnable poisons that was studied
Transient well flow in layered aquifer systems: the uniform well-face drawdown solution
Hemker, C. J.
1999-11-01
Previously a hybrid analytical-numerical solution for the general problem of computing transient well flow in vertically heterogeneous aquifers was proposed by the author. The radial component of flow was treated analytically, while the finite-difference technique was used for the vertical flow component only. In the present work the hybrid solution has been modified by replacing the previously assumed uniform well-face gradient (UWG) boundary condition in such a way that the drawdown remains uniform along the well screen. The resulting uniform well-face drawdown (UWD) solution also includes the effects of a finite diameter well, wellbore storage and a thin skin, while partial penetration and vertical heterogeneity are accommodated by the one-dimensional discretization. Solutions are proposed for well flow caused by constant, variable and slug discharges. The model was verified by comparing wellbore drawdowns and well-face flux distributions with published numerical solutions. Differences between UWG and UWD well flow will occur in all situations with vertical flow components near the well, which is demonstrated by considering: (1) partially penetrating wells in confined aquifers, (2) fully penetrating wells in unconfined aquifers with delayed response and (3) layered aquifers and leaky multiaquifer systems. The presented solution can be a powerful tool for solving many well-hydraulic problems, including well tests, flowmeter tests, slug tests and pumping tests. A computer program for the analysis of pumping tests, based on the hybrid analytical-numerical technique and UWG or UWD conditions, is available from the author.
Stirling Engine With Radial Flow Heat Exchangers
Vitale, N.; Yarr, George
1993-01-01
Conflict between thermodynamical and structural requirements resolved. In Stirling engine of new cylindrical configuration, regenerator and acceptor and rejector heat exchangers channel flow of working gas in radial direction. Isotherms in regenerator ideally concentric cylinders, and gradient of temperature across regenerator radial rather than axial. Acceptor and rejector heat exchangers located radially inward and outward of regenerator, respectively. Enables substantial increase in power of engine without corresponding increase in diameter of pressure vessel.
Choo, Y. K.; Civinskas, K. C.
1985-01-01
The three-dimensional inviscid DENTON code is used to analyze flow through a radial-inflow turbine rotor. Experimental data from the rotor are compared with analytical results obtained by using the code. The experimental data available for comparison are the radial distributions of circumferentially averaged values of absolute flow angle and total pressure downstream of the rotor exit. The computed rotor-exit flow angles are generally underturned relative to the experimental values, which reflect the boundary-layer separation at the trailing edge and the development of wakes downstream of the rotor. The experimental rotor is designed for a higher-than-optimum work factor of 1.126 resulting in a nonoptimum positive incidence and causing a region of rapid flow adjustment and large velocity gradients. For this experimental rotor, the computed radial distribution of rotor-exit to turbine-inlet total pressure ratios are underpredicted due to the errors in the finite-difference approximations in the regions of rapid flow adjustment, and due to using the relatively coarser grids in the middle of the blade region where the flow passage is highly three-dimensional. Additional results obtained from the three-dimensional inviscid computation are also presented, but without comparison due to the lack of experimental data. These include quasi-secondary velocity vectors on cross-channel surfaces, velocity components on the meridional and blade-to-blade surfaces, and blade surface loading diagrams. Computed results show the evolution of a passage vortex and large streamline deviations from the computational streamwise grid lines. Experience gained from applying the code to a radial turbine geometry is also discussed.
Choo, Y. K.; Civinskas, K. C.
1985-01-01
The three-dimensional inviscid DENTON code is used to analyze flow through a radial-inflow turbine rotor. Experimental data from the rotor are compared with analytical results obtained by using the code. The experimental data available for comparison are the radial distributions of circumferentially averaged values of absolute flow angle and total pressure downstream of the rotor exit. The computed rotor-exit flow angles are generally underturned relative to the experimental values, which reflect the boundary-layer separation at the trailing edge and the development of wakes downstream of the rotor. The experimental rotor is designed for a higher-than-optimum work factor of 1.126 resulting in a nonoptimum positive incidence and causing a region of rapid flow adjustment and large velocity gradients. For this experimental rotor, the computed radial distribution of rotor-exit to turbine-inlet total pressure ratios are underpredicted due to the errors in the finite-difference approximations in the regions of rapid flow adjustment, and due to using the relatively coarser grids in the middle of the blade region where the flow passage is highly three-dimensional. Additional results obtained from the three-dimensional inviscid computation are also presented, but without comparison due to the lack of experimental data. These include quasi-secondary velocity vectors on cross-channel surfaces, velocity components on the meridional and blade-to-blade surfaces, and blade surface loading diagrams. Computed results show the evolution of a passage vortex and large streamline deviations from the computational streamwise grid lines. Experience gained from applying the code to a radial turbine geometry is also discussed.
Bachegowda, Lohith S; Cheng, Yan H; Long, Thomas; Shaz, Beth H
2017-01-01
-Substantial variability between different antibody titration methods prompted development and introduction of uniform methods in 2008. -To determine whether uniform methods consistently decrease interlaboratory variation in proficiency testing. -Proficiency testing data for antibody titration between 2009 and 2013 were obtained from the College of American Pathologists. Each laboratory was supplied plasma and red cells to determine anti-A and anti-D antibody titers by their standard method: gel or tube by uniform or other methods at different testing phases (immediate spin and/or room temperature [anti-A], and/or anti-human globulin [AHG: anti-A and anti-D]) with different additives. Interlaboratory variations were compared by analyzing the distribution of titer results by method and phase. -A median of 574 and 1100 responses were reported for anti-A and anti-D antibody titers, respectively, during a 5-year period. The 3 most frequent (median) methods performed for anti-A antibody were uniform tube room temperature (147.5; range, 119-159), uniform tube AHG (143.5; range, 134-150), and other tube AHG (97; range, 82-116); for anti-D antibody, the methods were other tube (451; range, 431-465), uniform tube (404; range, 382-462), and uniform gel (137; range, 121-153). Of the larger reported methods, uniform gel AHG phase for anti-A and anti-D antibodies had the most participants with the same result (mode). For anti-A antibody, 0 of 8 (uniform versus other tube room temperature) and 1 of 8 (uniform versus other tube AHG), and for anti-D antibody, 0 of 8 (uniform versus other tube) and 0 of 8 (uniform versus other gel) proficiency tests showed significant titer variability reduction. -Uniform methods harmonize laboratory techniques but rarely reduce interlaboratory titer variance in comparison with other methods.
Klein, Fred W.
2016-01-01
Several lines of earthquake evidence indicate that the lithospheric plate is broken under the load of the island of Hawai`i, where the geometry of the lithosphere is circular with a central depression. The plate bends concave downward surrounding a stress-free hole, rather than bending concave upward as with past assumptions. Earthquake focal mechanisms show that the center of load stress and the weak hole is between the summits of Mauna Loa and Mauna Kea where the load is greatest. The earthquake gap at 21 km depth coincides with the predicted neutral plane of flexure where horizontal stress changes sign. Focal mechanism P axes below the neutral plane display a striking radial pattern pointing to the stress center. Earthquakes above the neutral plane in the north part of the island have opposite stress patterns; T axes tend to be radial. The M6.2 Honomu and M6.7 Kiholo main shocks (both at 39 km depth) are below the neutral plane and show radial compression, and the M6.0 Kiholo aftershock above the neutral plane has tangential compression. Earthquakes deeper than 20 km define a donut of seismicity around the stress center where flexural bending is a maximum. The hole is interpreted as the soft center where the lithospheric plate is broken. Kilauea's deep conduit is seismically active because it is in the ring of maximum bending. A simplified two-dimensional stress model for a bending slab with a load at one end yields stress orientations that agree with earthquake stress axes and radial P axes below the neutral plane. A previous inversion of deep Hawaiian focal mechanisms found a circular solution around the stress center that agrees with the model. For horizontal faults, the shear stress within the bending slab matches the slip in the deep Kilauea seismic zone and enhances outward slip of active flanks.
Radial pattern of nuclear decay processes
International Nuclear Information System (INIS)
Iskra, W.; Mueller, M.; Rotter, I.; Technische Univ. Dresden
1994-05-01
At high level density of nuclear states, a separation of different time scales is observed (trapping effect). We calculate the radial profile of partial widths in the framework of the continuum shell model for some 1 - resonances with 2p-2h nuclear structure in 16 O as a function of the coupling strength to the continuum. A correlation between the lifetime of a nuclear state and the radial profile of the corresponding decay process is observed. We conclude from our numerical results that the trapping effect creates structures in space and time characterized by a small radial extension and a short lifetime. (orig.)
Discontinuity effects in dynamically loaded tilting pad journal bearings
DEFF Research Database (Denmark)
Thomsen, Kim; Klit, Peder; Vølund, Anders
2011-01-01
This paper describes two discontinuity effects that can occur when modelling radial tilting pad bearings subjected to high dynamic loads. The first effect to be treated is a pressure build-up discontinuity effect. The second effect is a contact-related discontinuity that disappears when a contact...... force is included in the theoretical model. Methods for avoiding the pressure build-up discontinuity effect are proposed....
Intraluminal milrinone for dilation of the radial artery graft.
García-Rinaldi, R; Soltero, E R; Carballido, J; Mojica, J
1999-01-01
There is renewed interest in the use of the radial artery as a conduit for coronary artery bypass surgery. The radial artery is, however, a very muscular artery, prone to vasospasm. Milrinone, a potent vasodilator, has demonstrated vasodilatory properties superior to those of papaverine. In this report, we describe our technique of radial artery harvesting and the adjunctive use of intraluminal milrinone as a vasodilator in the preparation of this conduit for coronary artery bypass grafting. We have used these techniques in 25 patients who have undergone coronary artery bypass grafting using the radial artery. No hand ischemic complications have been observed in this group. Intraluminal milrinone appears to dilate and relax the radial artery, rendering this large conduit spasm free and very easy to use. We recommend the skeletonization technique for radial artery harvesting and the use of intraluminal milrinone as a radial artery vasodilator in routine myocardial revascularization. PMID:10524740
EFFICIENCY EVALUATION OF ENTERPRISE INFORMATION SYSTEMS WITH NON-UNIFORM LOAD
Directory of Open Access Journals (Sweden)
I. V. Kalinin
2015-09-01
Full Text Available The paper deals with the problem of characteristics evaluation for enterprise information systems at the design stage. In the design of ERP-systems the most interest characteristic is not the average time, but the probability of timely delivery of different type messages (for example, command, service, multimedia, files, etc. from the sender to the recipient. In addition,the possibility of using the priority information management built on the basis of service disciplines of general form with mixed priorities needs to be considered. An open queuing network with non-uniform data flow is used for solution of this problem. The method for calculation of information systems characteristics is proposed based on the decomposition of the network model. The end results obtained with this approach and by means of priority management are approximate because different classes of message streams at the output and input nodes of the computer system differ from the simple ones. However, result errors of the proposed analytical method are in acceptable limits for engineering calculations as it was shown by simulation in a wide range of parameters corresponding to real systems. Obtained results are usable for optimization problem solution of data transmission networks in modern information systems, involving routing algorithm definition and priorities specification for different classes of messages to provide given delivery time.
Coghetto Roland
2016-01-01
In this article, using mostly Pervin [9], Kunzi [6], [8], [7], Williams [11] and Bourbaki [3] works, we formalize in Mizar [2] the notions of quasiuniform space, semi-uniform space and locally uniform space.
Channeling of protons through radial deformed carbon nanotubes
Energy Technology Data Exchange (ETDEWEB)
Borka Jovanović, V., E-mail: vborka@vinca.rs [Atomic Physics Laboratory (040), Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia); Borka, D. [Atomic Physics Laboratory (040), Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia); Galijaš, S.M.D. [Faculty of Physics, University of Belgrade, P.O. Box 368, 11001 Belgrade (Serbia)
2017-05-18
Highlights: • For the first time we presented theoretically obtained distributions of channeled protons with radially deformed SWNT. • Our findings indicate that influence of the radial deformation is very strong and it should not be omitted in simulations. • We show that the spatial and angular distributions depend strongly of level of radial deformation of nanotube. • Our obtained results can be compared with measured distributions to reveal the presence of various types of defects in SWNT. - Abstract: In this paper we have presented a theoretical investigation of the channeling of 1 GeV protons with the radial deformed (10, 0) single-wall carbon nanotubes (SWNTs). We have calculated channeling potential within the deformed nanotubes. For the first time we presented theoretically obtained spatial and angular distributions of channeled protons with radially deformed SWNT. We used a Monte Carlo (MC) simulation technique. We show that the spatial and angular distributions depend strongly of level of radial deformation of nanotube. These results may be useful for nanotube characterization and production and guiding of nanosized ion beams.
Lian, Jianhui; Thomas, Daniel; Maraston, Claudia; Goddard, Daniel; Parikh, Taniya; Fernández-Trincado, J. G.; Roman-Lopes, Alexandre; Rong, Yu; Tang, Baitian; Yan, Renbin
2018-05-01
In our previous work, we found that only two scenarios are capable of reproducing the observed integrated mass-metallicity relations for the gas and stellar components of local star-forming galaxies simultaneously. One scenario invokes a time-dependent metal outflow loading factor with stronger outflows at early times. The other scenario uses a time-dependent initial mass function (IMF) slope with a steeper IMF at early times. In this work, we extend our study to investigate the radial profile of gas and stellar metallicity in local star-forming galaxies using spatially resolved spectroscopic data from the SDSS-IV MaNGA survey. We find that most galaxies show negative gradients in both gas and stellar metallicity with steeper gradients in stellar metallicity. The stellar metallicity gradients tend to be mass dependent with steeper gradients in more massive galaxies while no clear mass dependence is found for the gas metallicity gradient. Then we compare the observations with the predictions from a chemical evolution model of the radial profiles of gas and stellar metallicities. We confirm that the two scenarios proposed in our previous work are also required to explain the metallicity gradients. Based on these two scenarios, we successfully reproduce the radial profiles of gas metallicity, stellar metallicity, stellar mass surface density, and star formation rate surface density simultaneously. The origin of the negative gradient in stellar metallicity turns out to be driven by either radially dependent metal outflow or IMF slope. In contrast, the radial dependence of the gas metallicity is less constrained because of the degeneracy in model parameters.
Hérisson, Benjamin; Challamel, Noël; Picandet, Vincent; Perrot, Arnaud
2016-09-01
The static behavior of the Fermi-Pasta-Ulam (FPU) axial chain under distributed loading is examined. The FPU system examined in the paper is a nonlinear elastic lattice with linear and quadratic spring interaction. A dimensionless parameter controls the possible loss of convexity of the associated quadratic and cubic energy. Exact analytical solutions based on Hurwitz zeta functions are developed in presence of linear static loading. It is shown that this nonlinear lattice possesses scale effects and possible localization properties in the absence of energy convexity. A continuous approach is then developed to capture the main phenomena observed regarding the discrete axial problem. The associated continuum is built from a continualization procedure that is mainly based on the asymptotic expansion of the difference operators involved in the lattice problem. This associated continuum is an enriched gradient-based or nonlocal axial medium. A Taylor-based and a rational differential method are both considered in the continualization procedures to approximate the FPU lattice response. The Padé approximant used in the continualization procedure fits the response of the discrete system efficiently, even in the vicinity of the limit load when the non-convex FPU energy is examined. It is concluded that the FPU lattice system behaves as a nonlocal axial system in dynamic but also static loading.
Cheema, Tahseen; Salas, Christina; Morrell, Nathan; Lansing, Letitia; Reda Taha, Mahmoud M; Mercer, Deana
2012-04-01
Radial subluxation and cartilage thinning have been associated with initiation and accelerated development of osteoarthritis of the trapeziometacarpal joint. Few investigators have reported on the benefits of opening wedge trapezial osteotomy for altering the contact mechanics of the trapeziometacarpal joint as a possible deterrent to the initiation or progression of osteoarthritis. We used cadaveric specimens to determine whether opening wedge osteotomy of the trapezium was successful in reducing radial subluxation of the metacarpal base and to quantify the contact area and pressure on the trapezial surface during simulated lateral pinch. We used 8 fresh-frozen specimens in this study. The flexor pollicis longus, abductor pollicis longus, adductor pollicis, abductor pollicis brevis, and flexor pollicis brevis/opponens pollicis tendons were each loaded to simulate the thumb in lateral pinch position. We measured radial subluxation from anteroposterior radiographs before and after placement of a 15° wedge. We used real-time sensors to analyze contact pressure and contact area distribution on the trapezium. Center of force in the normal joint under lateral pinch loading was primarily located in the dorsal region of the trapezium. After wedge placement, contact pressure increased in the ulnar-dorsal region by 76%. Mean contact area increased in the ulnar-dorsal region from 0.05 to 0.07 cm(2), and in the ulnar-volar region from 0.003 to 0.024 cm(2). The average reduction in joint subluxation was 64%. The 15° opening wedge osteotomy of the trapezium reduced radial subluxation of the metacarpal on the trapezium and increased contact pressure and contact area away from the diseased compartments of the trapezial surface. Trapezial osteotomy addresses the 2 preeminent theories about the initiation and progression of osteoarthritis. By reducing radial subluxation and altering contact pressure and contact area, trapezial osteotomy may prove an alternative to first
Meshless Solution of the Problem on the Static Behavior of Thin and Thick Laminated Composite Beams
Xiang, S.; Kang, G. W.
2018-03-01
For the first time, the static behavior of laminated composite beams is analyzed using the meshless collocation method based on a thin-plate-spline radial basis function. In the approximation of a partial differential equation by using a radial basis function, the shape parameter has an important role in ensuring the numerical accuracy. The choice of a shape parameter in the thin plate spline radial basis function is easier than in other radial basis functions. The governing differential equations are derived based on Reddy's third-order shear deformation theory. Numerical results are obtained for symmetric cross-ply laminated composite beams with simple-simple and cantilever boundary conditions under a uniform load. The results found are compared with available published ones and demonstrate the accuracy of the present method.
Directory of Open Access Journals (Sweden)
Coghetto Roland
2016-09-01
Full Text Available In this article, using mostly Pervin [9], Kunzi [6], [8], [7], Williams [11] and Bourbaki [3] works, we formalize in Mizar [2] the notions of quasiuniform space, semi-uniform space and locally uniform space.
White, Kerry A.
2000-01-01
In 1994, Long Beach (California) Unified School District began requiring uniforms in all elementary and middle schools. Now, half of all urban school systems and many suburban schools have uniform policies. Research on uniforms' effectiveness is mixed. Tightened dress codes may be just as effective and less litigious. (MLH)
International Nuclear Information System (INIS)
Brown, S.J.; Fox, M.E.
1977-08-01
A structural problem that has received continued interest and development over the last several decades is the determination of stresses in two normally intersecting cylindrical shells subjected to internal pressure and external loading. In nuclear pressure vessels the external loading of the vessel through the attachment is encountered in thermal interaction, seismic loading and various postulated rupture or failure mechanisms. A simple technique, the Finite Plate Method, (FPM) is presented to analyze stresses in cylinder-to-cylinder junctures. The approach uses shallow shell formulations and a three term series expansion plate formulation, which limits the range of applicability. It is felt that the value of the method is its accuracy, economy, and ease in modeling a structure which falls within the range of applicability. Another appealing feature of the method is that its simplistic approach of superposition of results permits an easy extension to include additional loads not treated. For those mechanical loadings not developed, it is felt that their effect can either be accounted for by the mechanisms discussed or by simple calculations. Generally, the stresses resulting from torsional or transverse shear are small compared to the loads discussed, however, these shear effects may be included. Finally, in the instance of thermal stress within the cylinder-to-cylinder structure, it has been shown in an unpublished study by Brown that the FPM yields very good results for the range of curvatures discussed
Radial electric fields for improved tokamak performance
International Nuclear Information System (INIS)
Downum, W.B.
1981-01-01
The influence of externally-imposed radial electric fields on the fusion energy output, energy multiplication, and alpha-particle ash build-up in a TFTR-sized, fusing tokamak plasma is explored. In an idealized tokamak plasma, an externally-imposed radial electric field leads to plasma rotation, but no charge current flows across the magnetic fields. However, a realistically-low neutral density profile generates a non-zero cross-field conductivity and the species dependence of this conductivity allows the electric field to selectively alter radial particle transport
Flow performance of highly loaded axial fan with bowed rotor blades
Chen, L.; Liu, X. J.; Yang, A. L.; Dai, R.
2013-12-01
In this paper, a partial bowed rotor blade was proposed for a newly designed high loaded axial fan. The blade was positively bowed 30 degrees from hub to 30 percent spanwise position. Flows of radial blade and bowed blade fans were numerically compared for various operation conditions. Results show that the fan's performance is improved. At the designed condition with flow coefficient of 0.52, the efficiency of the bowed blade fan is increased 1.44% and the static pressure rise is increased 11%. Comparing the flow structures, it can be found that the separated flow in the bowed fan is reduced and confined within 20 percent span, which is less than the 35 percent in the radial fan. It means that the bowed blade generates negative blade force and counteracts partial centrifugal force. It is alleviates the radial movements of boundary layers in fan's hub region. Flow losses due to 3D mixing are reduced in the rotor. Inlet flow to downstream stator is also improved.
Interactions between Radial Electric Field, Transport and Structure in Helical Plasmas
International Nuclear Information System (INIS)
Ida, Katsumi and others
2006-01-01
Control of the radial electric field is considered to be important in helical plasmas, because the radial electric field and its shear are expected to reduce neoclassical and anomalous transport, respectively. Particle and heat transport, that determines the radial structure of density and electron profiles, sensitive to the structure of radial electric field. On the other hand, the radial electric field itself is determined by the plasma parameters. In general, the sign of the radial electric field is determined by the plasma collisionality, while the magnitude of the radial electric field is determined by the temperature and/or density gradients. Therefore the structure of radial electric field and temperature and density are strongly coupled through the particle and heat transport and formation mechanism of radial electric field. Interactions between radial electric field, transport and structure in helical plasmas is discussed based on the experiments on Large Helical Device
Anomalous Medial Branch of Radial Artery: A Rare Variant
Directory of Open Access Journals (Sweden)
Surbhi Wadhwa
2016-10-01
Full Text Available Radial artery is an important consistent vessel of the upper limb. It is a useful vascular access site for coronary procedures and its reliable anatomy has resulted in an elevation of radial forearm flaps for reconstructive surgeries of head and neck. Technical failures, in both the procedures, are mainly due to anatomical variations, such as radial loops, ectopic radial arteries or tortuosity in the vessel. We present a rare and a unique anomalous medial branch of the radial artery spiraling around the flexor carpi radialis muscle in the forearm with a high rising superficial palmar branch of radial artery. Developmentally it probably is a remanent of the normal pattern of capillary vessel maintenance and regression. Such a case is of importance for reconstructive surgeons and coronary interventionists, especially in view of its unique medial and deep course.
Fuel radial design using Path Relinking; Diseno radial de combustible usando Path Relinking
Energy Technology Data Exchange (ETDEWEB)
Campos S, Y. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)
2007-07-01
The present work shows the obtained results when implementing the combinatory optimization technique well-known as Path Re linking (Re-linkage of Trajectories), to the problem of the radial design of nuclear fuel assemblies, for boiling water reactors (BWR Boiling Water Reactor by its initials in English), this type of reactors is those that are used in the Laguna Verde Nucleo electric Central, Veracruz. As in any other electric power generation plant of that make use of some fuel to produce heat and that it needs each certain time (from 12 to 14 months) to make a supply of the same one, because this it wears away or it burns, in the nucleolectric plants to this activity is denominated fuel reload. In this reload different activities intervene, among those which its highlight the radial and axial designs of fuel assemblies, the patterns of control rods and the multi cycles study, each one of these stages with their own complexity. This work was limited to study in independent form the radial design, without considering the other activities. These phases are basic for the fuel reload design and of reactor operation strategies. (Author)
SU-F-18C-11: Diameter Dependency of the Radial Dose Distribution in a Long Polyethylene Cylinder
Energy Technology Data Exchange (ETDEWEB)
Bakalyar, D; McKenney, S [Henry Ford Health System, Detroit, MI (United States); Feng, W [New York Presbyterian Hospital, Tenafly, NJ (United States)
2014-06-15
Purpose: The radial dose distribution in the central plane of a long cylinder following a long CT scan depends upon the diameter and composition of the cylinder. An understanding of this behavior is required for determining the spatial average of the dose in the central plane. Polyethylene, the material for construction of the TG200/ICRU phantom (30 cm in diameter) was used for this study. Size effects are germane to the principles incorporated in size specific dose estimates (SSDE); thus diameter dependency was explored as well. Method: ssuming a uniform cylinder and cylindrically symmetric conditions of irradiation, the dose distribution can be described using a radial function. This function must be an even function of the radial distance due to the conditions of symmetry. Two effects are accounted for: The direct beam makes its weakest contribution at the center while the contribution due to scatter is strongest at the center and drops off abruptly at the outer radius. An analytic function incorporating these features was fit to Monte Carlo results determined for infinite polyethylene cylinders of various diameters. A further feature of this function is that it is integrable. Results: Symmetry and continuity dictate a local extremum at the center which is a minimum for the larger sizes. The competing effects described above can Resultin an absolute maximum occurring between the center and outer edge of the cylinders. For the smallest cylinders, the maximum dose may occur at the center. Conclusion: An integrable, analytic function can be used to characterize the radial dependency of dose for cylindrical CT phantoms of various sizes. One use for this is to help determine average dose distribution over the central cylinder plane when equilibrium dose has been reached.
Pacheco, Anderson; Fontana, Filipe; Viotti, Matias R.; Veiga, Celso L. N.; Lothhammer, Lívia R.; Albertazzi G., Armando, Jr.
2015-08-01
The authors developed an achromatic speckle pattern interferometer able to measure in-plane displacements in polar coordinates. It has been used to measure combined stresses resulting from the superposition of mechanical loading and residual stresses. Relaxation methods have been applied to produce on the surface of the specimen a displacement field that can be used to determine the amount of combined stresses. Two relaxation methods are explored in this work: blind hole-drilling and indentation. The first one results from a blind hole drilled with a high-speed drilling unit in the area of interest. The measured displacement data is fitted in an appropriate model to quantify the stress level using an indirect approach based on a set of finite element coefficients. The second approach uses indentation, where a hard spherical tip is firmly pressed against the surface to be measured with a predetermined indentation load. A plastic flow occurs around the indentation mark producing a radial in-plane displacement field that is related to the amount of combined stresses. Also in this case, displacements are measured by the radial interferometer and used to determine the stresses by least square fitting it to a displacement field determined by calibration. Both approaches are used to quantify the amount of bending stresses and moment in eight sections of a 12 m long 200 mm diameter steel pipe submitted to a known transverse loading. Reference values of bending stresses are also determined by strain gauges. The comparison between the four results is discussed in the paper.
Chen, Hongwei; Wang, Ziyang; Shang, Yongjun
2018-06-01
To compare clinical outcomes of unipolar and bipolar radial head prosthesis in the treatment of patients with radial head fracture. Medline, Cochrane, EMBASE, Google Scholar databases were searched until April 18, 2016 using the following search terms: radial head fracture, elbow fracture, radial head arthroplasty, implants, prosthesis, unipolar, bipolar, cemented, and press-fit. Randomized controlled trials, retrospective, and cohort studies were included. The Mayo elbow performance score (MEPS), disabilities of the arm, shoulder, and hand (DASH) score, radiologic assessment, ROM, and grip strength following elbow replacement were similar between prosthetic devices. The pooled mean excellent/good ranking of MEPS was 0.78 for unipolar and 0.73 for bipolar radial head arthroplasty, and the pooled mean MEPS was 86.9 and 79.9, respectively. DASH scores for unipolar and bipolar prosthesis were 19.0 and 16.3, respectively. Range of motion outcomes were similar between groups, with both groups have comparable risk of flexion arc, flexion, extension deficit, rotation arc, pronation, and supination (p values bipolar prosthesis). However, bipolar radial head prosthesis was associated with an increased chance of heterotopic ossification and lucency (p values ≤0.049) while unipolar prosthesis was not (p values ≥0.088). Both groups had risk for development of capitellar osteopenia or erosion/wear (p values ≤0.039). Unipolar and bipolar radial head prostheses were similar with respect to clinical outcomes. Additional comparative studies are necessary to further compare different radial head prostheses used to treat radial head fracture.
Gui, Xulong; Luo, Xiaobing; Wang, Xiaoping; Liu, Sheng
2015-12-01
Micro-electrical-mechanical system (MEMS) has become important for many industries such as automotive, home appliance, portable electronics, especially with the emergence of Internet of Things. Volume testing with temperature compensation has been essential in order to provide MEMS based sensors with repeatability, consistency, reliability, and durability, but low cost. Particularly, in the temperature calibration test, temperature uniformity of thermal cycling based calibration chamber becomes more important for obtaining precision sensors, as each sensor is different before the calibration. When sensor samples are loaded into the chamber, we usually open the door of the chamber, then place fixtures into chamber and mount the samples on the fixtures. These operations may affect temperature uniformity in the chamber. In order to study the influencing factors of sample-loading on the temperature uniformity in the chamber during calibration testing, numerical simulation work was conducted first. Temperature field and flow field were simulated in empty chamber, chamber with open door, chamber with samples, and chamber with fixtures, respectively. By simulation, it was found that opening chamber door, sample size and number of fixture layers all have effects on flow field and temperature field. By experimental validation, it was found that the measured temperature value was consistent with the simulated temperature value.
Directory of Open Access Journals (Sweden)
Mišković Žarko Z.
2016-01-01
Full Text Available One of the most important factors influencing ball bearings service life is its internal radial clearance. However, this parameter is also very complex because it depends on applied radial load and ball bearings dimensions, surface finish and manufacturing materials. Thermal condition of ball bearings also significantly affects internal radial clearance. Despite many researches performed in order to find out relevant facts about different aspects of ball bearings thermal behaviour, only few of them are dealing with the real working conditions, where high concentration of solid contaminant particles is present. That’s why the main goal of research presented in this paper was to establish statistically significant correlation between ball bearings temperatures, their working time and concentration of contaminant particles in their grease. Because of especially difficult working conditions, the typical conveyor idlers bearings were selected as representative test samples and appropriate solid particles from open pit coal mines were used as artificial contaminants. Applied experimental methodology included thermographic inspection, as well as usage of custom designed test rig for ball bearings service life testing. Finally, by obtained experimental data processing in advanced software, statistically significant mathematical correlation between mentioned bearings characteristics was determined and applied in commonly used internal radial clearance equation. That is the most important contribution of performed research - the new equation and methodology for ball bearings internal clearance determination which could be used for eventual improvement of existing bearings service life equations. [Projekat Ministarstva nauke Republike Srbije, br. TR35029 i br. TR14033
Vitreous veils and radial lattice in Marshall syndrome.
Brubaker, Jacob W; Mohney, Brian G; Pulido, Jose S; Babovic-Vuksanovic, Dusica
2008-12-01
To report the findings of membranous vitreous veils and radial lattice in a child with Marshall syndrome. Observational case report. Retrospective review of medical records and fundus photograph of a 6-year-old boy with Marshall syndrome. Vitreoretinal findings were significant for bilateral membranous vitreous veils and radial lattice degeneration. This case demonstrates the occurrence of vitreous veils and radial lattice degeneration in patients with Marshall syndrome.
Mansat, Pierre
2016-01-01
Radial head arthroplasty is used to stabilize the joint after a complex acute radial head fracture that is not amenable for fixation or to treat sequelae of radial head fractures. Most of the currently used radial head prostheses are metallic monoblock implants that are not consistently adaptable and raise technical challenges since their implantation requires lateral elbow subluxation. Metallic modular radial head arthroplasty implants available in various head and stem sizes have been devel...
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Wilson David A
2007-11-01
Full Text Available Abstract The purpose of this investigation was to design and verify the capabilities of an in vitro loading-measurement system that mimics in vivo unconstrained three dimensional (3D relative motion between long bone ends, applies uniform load components over the entire length of a test specimen, and measures 3D relative motion between test segment ends to directly determine test segment construct stiffness free of errors due to potting-fixture-test machine finite stiffness. Intact equine cadaveric radius bones, which were subsequently osteotomized/ostectomized and instrumented with bone plates were subjected to non-destructive axial, torsion, and 4-point bending loads through fixtures designed to allow unconstrained components of non-load associated 3D relative motion between radius ends. 3D relative motion between ends of a 50 mm long test segment was measured by an infrared optical tracking system to directly determine its stiffness. Each specimen was then loaded to ultimate failure in either torsion or bending. Cortical bone cross-section diameters and published bone biomechanical properties were substituted into classical mechanics equations to predict the intact test segment theoretical stiffness for comparison and thus loading-measurement system verification. Intact measured stiffness values were the same order of magnitude as theoretically predicted. The primary component of relative motion between ends of the test segment corresponded to that of the applied load with the other 3D components being evident and consistent in relative magnitude and direction for unconstrained loading of an unsymmetrical double plate oblique fracture configuration. Bone failure configurations were reproducible and consistent with theoretically predicted. The 3D loading-measurement system designed: a mimics unconstrained relative 3D motion between radius ends that occurs in clinical situations, b applies uniform compression, torsion, and 4-point bending loads
Przednowek, Krzysztof; Iskra, Janusz; Wiktorowicz, Krzysztof; Krzeszowski, Tomasz; Maszczyk, Adam
2017-12-01
This paper presents a novel approach to planning training loads in hurdling using artificial neural networks. The neural models performed the task of generating loads for athletes' training for the 400 meters hurdles. All the models were calculated based on the training data of 21 Polish National Team hurdlers, aged 22.25 ± 1.96, competing between 1989 and 2012. The analysis included 144 training plans that represented different stages in the annual training cycle. The main contribution of this paper is to develop neural models for planning training loads for the entire career of a typical hurdler. In the models, 29 variables were used, where four characterized the runner and 25 described the training process. Two artificial neural networks were used: a multi-layer perceptron and a network with radial basis functions. To assess the quality of the models, the leave-one-out cross-validation method was used in which the Normalized Root Mean Squared Error was calculated. The analysis shows that the method generating the smallest error was the radial basis function network with nine neurons in the hidden layer. Most of the calculated training loads demonstrated a non-linear relationship across the entire competitive period. The resulting model can be used as a tool to assist a coach in planning training loads during a selected training period.
Directory of Open Access Journals (Sweden)
Przednowek Krzysztof
2017-12-01
Full Text Available This paper presents a novel approach to planning training loads in hurdling using artificial neural networks. The neural models performed the task of generating loads for athletes’ training for the 400 meters hurdles. All the models were calculated based on the training data of 21 Polish National Team hurdlers, aged 22.25 ± 1.96, competing between 1989 and 2012. The analysis included 144 training plans that represented different stages in the annual training cycle. The main contribution of this paper is to develop neural models for planning training loads for the entire career of a typical hurdler. In the models, 29 variables were used, where four characterized the runner and 25 described the training process. Two artificial neural networks were used: a multi-layer perceptron and a network with radial basis functions. To assess the quality of the models, the leave-one-out cross-validation method was used in which the Normalized Root Mean Squared Error was calculated. The analysis shows that the method generating the smallest error was the radial basis function network with nine neurons in the hidden layer. Most of the calculated training loads demonstrated a non-linear relationship across the entire competitive period. The resulting model can be used as a tool to assist a coach in planning training loads during a selected training period.
Clem, Michelle M.; Woike, Mark R.
2013-01-01
The Aeronautical Sciences Project under NASA`s Fundamental Aeronautics Program is extremely interested in the development of novel measurement technologies, such as optical surface measurements in the internal parts of a flow path, for in situ health monitoring of gas turbine engines. In situ health monitoring has the potential to detect flaws, i.e. cracks in key components, such as engine turbine disks, before the flaws lead to catastrophic failure. In the present study, a cross-correlation imaging technique is investigated in a proof-of-concept study as a possible optical technique to measure the radial growth and strain field on an already cracked sub-scale turbine engine disk under loaded conditions in the NASA Glenn Research Center`s High Precision Rotordynamics Laboratory. The optical strain measurement technique under investigation offers potential fault detection using an applied high-contrast random speckle pattern and imaging the pattern under unloaded and loaded conditions with a CCD camera. Spinning the cracked disk at high speeds induces an external load, resulting in a radial growth of the disk of approximately 50.0-im in the flawed region and hence, a localized strain field. When imaging the cracked disk under static conditions, the disk will be undistorted; however, during rotation the cracked region will grow radially, thus causing the applied particle pattern to be .shifted`. The resulting particle displacements between the two images will then be measured using the two-dimensional cross-correlation algorithms implemented in standard Particle Image Velocimetry (PIV) software to track the disk growth, which facilitates calculation of the localized strain field. In order to develop and validate this optical strain measurement technique an initial proof-of-concept experiment is carried out in a controlled environment. Using PIV optimization principles and guidelines, three potential speckle patterns, for future use on the rotating disk, are developed
Radial head fracture associated with posterior interosseous nerve injury
Directory of Open Access Journals (Sweden)
Bernardo Barcellos Terra
Full Text Available ABSTRACT Fractures of the radial head and radial neck correspond to 1.7-5.4% of all fractures and approximately 30% may present associated injuries. In the literature, there are few reports of radial head fracture with posterior interosseous nerve injury. This study aimed to report a case of radial head fracture associated with posterior interosseous nerve injury. CASE REPORT: A male patient, aged 42 years, sought medical care after falling from a skateboard. The patient related pain and limitation of movement in the right elbow and difficulty to extend the fingers of the right hand. During physical examination, thumb and fingers extension deficit was observed. The wrist extension showed a slight radial deviation. After imaging, it became evident that the patient had a fracture of the radial head that was classified as grade III in the Mason classification. The patient underwent fracture fixation; at the first postoperative day, thumb and fingers extension was observed. Although rare, posterior interosseous nerve branch injury may be associated with radial head fractures. In the present case, the authors believe that neuropraxia occurred as a result of the fracture hematoma and edema.
Masuda, Shumpei; Nakamura, Katsuhiro; Nakahara, Mikio
2018-02-01
We study phase imprinting on Bose-Einstein condensates (BECs) with the fast-forward scaling theory revealing a nontrivial scaling property in quantum dynamics. We introduce a wave packet with uniform momentum density (WPUM) which has peculiar properties but is short-lived. The fast-forward scaling theory is applied to derive the driving potential for creation of the WPUMs in a predetermined time. Fast manipulation is essential for the creation of WPUMs because of the instability of the state. We also study loading of a BEC into a predetermined Bloch state in the lowest band from the ground state of a periodic potential. Controlled linear potential is not sufficient for creation of the Bloch state with large wavenumber because the change in the amplitude of the order parameter is not negligible. We derive the exact driving potential for creation of predetermined Bloch states using the obtained theory.
Radial Field Piezoelectric Diaphragms
Bryant, R. G.; Effinger, R. T., IV; Copeland, B. M., Jr.
2002-01-01
A series of active piezoelectric diaphragms were fabricated and patterned with several geometrically defined Inter-Circulating Electrodes "ICE" and Interdigitated Ring Electrodes "ICE". When a voltage potential is applied to the electrodes, the result is a radially distributed electric field that mechanically strains the piezoceramic along the Z-axis (perpendicular to the applied electric field). Unlike other piezoelectric bender actuators, these Radial Field Diaphragms (RFDs) strain concentrically yet afford high displacements (several times that of the equivalent Unimorph) while maintaining a constant circumference. One of the more intriguing aspects is that the radial strain field reverses itself along the radius of the RFD while the tangential strain remains relatively constant. The result is a Z-deflection that has a conical profile. This paper covers the fabrication and characterization of the 5 cm. (2 in.) diaphragms as a function of poling field strength, ceramic thickness, electrode type and line spacing, as well as the surface topography, the resulting strain field and displacement as a function of applied voltage at low frequencies. The unique features of these RFDs include the ability to be clamped about their perimeter with little or no change in displacement, the environmentally insulated packaging, and a highly repeatable fabrication process that uses commodity materials.
High-uniformity centimeter-wide Si etching method for MEMS devices with large opening elements
Okamoto, Yuki; Tohyama, Yukiya; Inagaki, Shunsuke; Takiguchi, Mikio; Ono, Tomoki; Lebrasseur, Eric; Mita, Yoshio
2018-04-01
We propose a compensated mesh pattern filling method to achieve highly uniform wafer depth etching (over hundreds of microns) with a large-area opening (over centimeter). The mesh opening diameter is gradually changed between the center and the edge of a large etching area. Using such a design, the etching depth distribution depending on sidewall distance (known as the local loading effect) inversely compensates for the over-centimeter-scale etching depth distribution, known as the global or within-die(chip)-scale loading effect. Only a single DRIE with test structure patterns provides a micro-electromechanical systems (MEMS) designer with the etched depth dependence on the mesh opening size as well as on the distance from the chip edge, and the designer only has to set the opening size so as to obtain a uniform etching depth over the entire chip. This method is useful when process optimization cannot be performed, such as in the cases of using standard conditions for a foundry service and of short turn-around-time prototyping. To demonstrate, a large MEMS mirror that needed over 1 cm2 of backside etching was successfully fabricated using as-is-provided DRIE conditions.
Institute of Scientific and Technical Information of China (English)
Linda
2008-01-01
The uniforms for Beijing Olympics’ workers, technical staff and volunteers have been unveiled to mark the 200-day countdown to the Games. The uniforms feature the key element of the clouds of promise and will be in three colors:red for Beijing Olympic Games Committee staff, blue
Directory of Open Access Journals (Sweden)
Ahn KT
2016-04-01
Full Text Available Kye Taek Ahn, Kwang-In Park, Mi Joo Kim, Jin Kyung Oh, Ji Hye Han, Hee Jin Kwon, Seon-Ah Jin, Jun-Hyung Kim, Jae-Hyeong Park, Jae-Hwan Lee, Si Wan Choi, In-Whan Seong, Jin-Ok Jeong Department of Internal Medicine, Division of Cardiology, Chungnam National University Hospital, Chungnam National University School of Medicine, Daejeon, Republic of Korea Objectives: Central hemodynamics may better represent the load imposed on the coronary and cerebral arteries and thereby bear a stronger relationship to cardiovascular outcomes. Methods: Patients who had confirmed hypertension as assessed by daytime 24-hour ambulatory blood pressure monitoring (≥135/85 mmHg were enrolled. Central blood pressure and radial augmentation index (AIx corrected for a heart rate of 75 bpm (radial AIx 75 were measured for all patients. We evaluated the association of age, height, and sex with central hemodynamics in patients with never-treated hypertension. Results: A total of 203 patients were enrolled, of whom men numbered 101 (49.7%. The median height of all patients was 162 cm, and mean age was 53.2 years. In the Pearson correlation analysis, regardless of sex difference (R=-0.627 for height, R=0.035 for age, P-value =0.005, a stronger relationship was observed between height and radial AIx 75 than between age and radial AIx 75. In the multiple regression analysis, the sex difference and height were strongly associated with elevated radial AIx 75 in all patients (adjusted R2=0.428, β=6.237, 95% confidence interval [CI] for women 1.480–10.995, P-value =0.011 and β=-0.632, 95% CI for height -0.929 to -0.335, P-value =0.009, respectively. Conclusion: In patients with never-treated hypertension, female sex and shorter height are the important risk factors of elevated radial AIx 75. Keywords: hypertension, augmentation index, height, sex
Radial transport with perturbed magnetic field
Energy Technology Data Exchange (ETDEWEB)
Hazeltine, R. D. [Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States)
2015-05-15
It is pointed out that the viscosity coefficient describing radial transport of toroidal angular momentum is proportional to the second power of the gyro-radius—like the corresponding coefficients for particle and heat transport—regardless of any geometrical symmetry. The observation is widely appreciated, but worth emphasizing because some literature gives the misleading impression that asymmetry can allow radial moment transport in first-order.
Radial transport with perturbed magnetic field
International Nuclear Information System (INIS)
Hazeltine, R. D.
2015-01-01
It is pointed out that the viscosity coefficient describing radial transport of toroidal angular momentum is proportional to the second power of the gyro-radius—like the corresponding coefficients for particle and heat transport—regardless of any geometrical symmetry. The observation is widely appreciated, but worth emphasizing because some literature gives the misleading impression that asymmetry can allow radial moment transport in first-order
Optimizing load transfer in multiwall nanotubes through interwall coupling: Theory and simulation
International Nuclear Information System (INIS)
Byrne, E.M.; Letertre, A.; McCarthy, M.A.; Curtin, W.A.; Xia, Z.
2010-01-01
An analytical model is developed to determine the length scales over which load is transferred from outer to inner walls of multiwall carbon nanotubes (MWCNTs) as a function of the amount of bonding between walls. The model predicts that the characteristic length for load transfer scales as l∼t√(E/μ-bar), where t is the CNT wall spacing, E is the effective wall Young's modulus, and μ-bar is the average interwall shear modulus due to interwall coupling. Molecular dynamics simulations for MWCNTs with up to six walls, and with interwall coupling achieved by interwall sp 3 bonding at various densities, provide data against which the model is tested. For interwall bonding having a uniform axial distribution, the analytic and simulation models agree well, showing that continuum mechanics concepts apply down to the atomic scale in this problem. The simulation models show, however, that load transfer is sensitive to natural statistical fluctuations in the spatial distribution of the interwall bonding between pairs of walls, and such fluctuations generally increase the net load transfer length needed to fully load an MWCNT. Optimal load transfer is achieved when bonding is uniformly distributed axially, and all interwall regions have the same shear stiffness, implying a linear decrease in the number of interwall bonds with distance from the outer wall. Optimal load transfer into an n-wall MWCNT is shown to occur over a length of ∼1.5nl. The model can be used to design MWCNTs for structural materials, and to interpret load transfer characteristics deduced from experiments on individual MWCNTs.
International Nuclear Information System (INIS)
Ray, M C
2010-01-01
A new hybrid piezoelectric composite (HPZC) reinforced with zigzag single-walled carbon nanotubes (CNTs) and piezoelectric fibers is proposed. The novel constructional feature of this composite is that the uniformly aligned CNTs are radially grown on the surface of piezoelectric fibers. A micromechanics model is derived to estimate the effective piezoelectric and elastic properties. It is found that the effective piezoelectric coefficient e 31 of the proposed HPZC, which accounts for the in-plane actuation, is significantly higher than that of the existing 1-3 piezoelectric composite without reinforcement with carbon nanotubes and the previously reported hybrid piezoelectric composite (Ray and Batra 2009 ASME J. Appl. Mech. 76 034503)
Energy Technology Data Exchange (ETDEWEB)
Brasz, J.J.; Hartmann, K. [Carrier Corp., Syracuse, NY (United States)]|[Carrier Corp., Muenchen (Germany)
2006-07-01
The relative part-load performance of screw compressors and radial compressors is compared. Compressor part load is represented by a 2D characteristic field with the pressure on the vertical axis as a function of mass flow on the horizontal axis, with efficiencies given for any possible combination of pressure and mass flow. While this manner of representation is common for radial compressors, it is new for screw compressors. In the comparison of compression efficiencies, the focus is on vapour compression. For a valid comparative assessment of total compression, also the mechanical and/or electric loss through bearings, transmission, drive and (in case of variable-speed drives) frequency converters must be taken into account. (orig.)
Mitochondrial DNA mutation load in a family with the m.8344A>G point mutation and lipomas
DEFF Research Database (Denmark)
Jeppesen, Tina Dysgaard; Al-Hashimi, Noor; Duno, Morten
2017-01-01
Studies have shown that difference in mtDNA mutation load among tissues is a result of postnatal modification. We present five family members with the m.8344A>G with variable phenotypes but uniform intrapersonal distribution of mutation load, indicating that there is no postnatal modification of mt......DNA mutation load in this genotype....
Chen, Yibin; Chen, Jiaxi; Chen, Xuan; Wang, Min; Wang, Wei
2015-01-01
A new method of uniform sampling is evaluated in this paper. The items and indexes were adopted to evaluate the rationality of the uniform sampling. The evaluation items included convenience of operation, uniformity of sampling site distribution, and accuracy and precision of measured results. The evaluation indexes included operational complexity, occupation rate of sampling site in a row and column, relative accuracy of pill weight, and relative deviation of pill weight. They were obtained from three kinds of drugs with different shape and size by four kinds of sampling methods. Gray correlation analysis was adopted to make the comprehensive evaluation by comparing it with the standard method. The experimental results showed that the convenience of uniform sampling method was 1 (100%), odds ratio of occupation rate in a row and column was infinity, relative accuracy was 99.50-99.89%, reproducibility RSD was 0.45-0.89%, and weighted incidence degree exceeded the standard method. Hence, the uniform sampling method was easy to operate, and the selected samples were distributed uniformly. The experimental results demonstrated that the uniform sampling method has good accuracy and reproducibility, which can be put into use in drugs analysis.
Concepts of radial and angular kinetic energies
DEFF Research Database (Denmark)
Dahl, Jens Peder; Schleich, W.P.
2002-01-01
We consider a general central-field system in D dimensions and show that the division of the kinetic energy into radial and angular parts proceeds differently in the wave-function picture and the Weyl-Wigner phase-space picture, Thus, the radial and angular kinetic energies are different quantities...
Blade design loads on the flow exciting force in centrifugal pump
International Nuclear Information System (INIS)
Xu, Y; Yang, A L; Langand, D P; Dai, R
2012-01-01
The three-dimensional viscous flow field of two centrifugal pumps, which have the same volute, design head, design flow rate and rotational speed but the blade design load, are analyzed based on large eddy simulation. The comparisons are implemented including the hydraulic efficiencies, flow field characteristics, pressure pulsations and unsteady forces applied on the impellers to investigate the effect of the design blade load on hydraulic performance and flow exciting force. The numerical results show that the efficiency of the pump, the impeller blade of which has larger design load, is improved by 1.1%∼2.9% compared to the centrifugal pump with lower blade design load. The pressure fluctuation of the pump with high design load is more remarkable. Its maximum amplitude of coefficient of static pressure is higher by 43% than the latter. At the same time the amplitude of unsteady radial force is increased by 11.6% in the time domain. The results also imply that the blade design load is an important factor on the excitation force in centrifugal pumps.
Effects of radial diffuser hydraulic design on a double-suction centrifugal pump
Hou, H. C.; Zhang, Y. X.; Xu, C.; Zhang, J. Y.; Li, Z. L.
2016-05-01
In order to study effects of radial diffuser on hydraulic performance of crude oil pump, the steady CFD numerical method is applied and one large double-suction oil pump running in long-distance pipeline is considered. The research focuses on analysing the influence of its diffuser vane profile on hydraulic performance of oil pump. The four different types of cylindrical vane have been designed by in-house codes mainly including double arcs (DA), triple arcs (TA), equiangular spiral line (ES) and linear variable angle spiral line (LVS). During design process diffuser vane angles at inlet and outlet are tentatively given within a certain range and then the wrapping angle of the four types of diffuser vanes can be calculated automatically. Under the given inlet and outlet angles, the linear variable angle spiral line profile has the biggest wrapping angle and profile length which is good to delay channel diffusion but bring more friction hydraulic loss. Finally the vane camber line is thickened at the certain uniform thickness distribution and the 3D diffuser models are generated. The whole flow passage of oil pump with different types of diffusers under various flow rate conditions are numerically simulated based on RNG k-ɛ turbulent model and SIMPLEC algorithm. The numerical results show that different types of diffusers can bring about great difference on the hydraulic performance of oil pump, of which the ES profile diffuser with its proper setting angle shows the best hydraulic performance and its inner flow field is improved obviously. Compared with the head data from model sample, all designed diffusers can make a certain improvement on head characteristic. At the large flow rate conditions the hydraulic efficiency increases obviously and the best efficiency point shift to the large flow rate range. The ES profile diffuser embodies the better advantages on pump performance which can be explained theoretically that the diffuser actually acts as a diffusion
Tunali, Ilke; Stringfield, Olya; Guvenis, Albert; Wang, Hua; Liu, Ying; Balagurunathan, Yoganand; Lambin, Philippe; Gillies, Robert J; Schabath, Matthew B
2017-11-10
The goal of this study was to extract features from radial deviation and radial gradient maps which were derived from thoracic CT scans of patients diagnosed with lung adenocarcinoma and assess whether these features are associated with overall survival. We used two independent cohorts from different institutions for training (n= 61) and test (n= 47) and focused our analyses on features that were non-redundant and highly reproducible. To reduce the number of features and covariates into a single parsimonious model, a backward elimination approach was applied. Out of 48 features that were extracted, 31 were eliminated because they were not reproducible or were redundant. We considered 17 features for statistical analysis and identified a final model containing the two most highly informative features that were associated with lung cancer survival. One of the two features, radial deviation outside-border separation standard deviation, was replicated in a test cohort exhibiting a statistically significant association with lung cancer survival (multivariable hazard ratio = 0.40; 95% confidence interval 0.17-0.97). Additionally, we explored the biological underpinnings of these features and found radial gradient and radial deviation image features were significantly associated with semantic radiological features.
Illumination Profile & Dispersion Variation Effects on Radial Velocity Measurements
Grieves, Nolan; Ge, Jian; Thomas, Neil B.; Ma, Bo; Li, Rui; SDSS-III
2015-01-01
The Multi-object APO Radial-Velocity Exoplanet Large-Area Survey (MARVELS) measures radial velocities using a fiber-fed dispersed fixed-delay interferometer (DFDI) with a moderate dispersion spectrograph. This setup allows a unique insight into the 2D illumination profile from the fiber on to the dispersion grating. Illumination profile investigations show large changes in the profile over time and fiber location. These profile changes are correlated with dispersion changes and long-term radial velocity offsets, a major problem within the MARVELS radial velocity data. Characterizing illumination profiles creates a method to both detect and correct radial velocity offsets, allowing for better planet detection. Here we report our early results from this study including improvement of radial velocity data points from detected giant planet candidates. We also report an illumination profile experiment conducted at the Kitt Peak National Observatory using the EXPERT instrument, which has a DFDI mode similar to MARVELS. Using profile controlling octagonal-shaped fibers, long term offsets over a 3 month time period were reduced from ~50 m/s to within the photon limit of ~4 m/s.
Kumano, Teruhisa
As known well, two of the fundamental processes which give rise to voltage collapse in power systems are the on load tap changers of transformers and dynamic characteristics of loads such as induction machines. It has been well established that, comparing among these two, the former makes slower collapse while the latter makes faster. However, in realistic situations, the load level of each induction machine is not uniform and it is well expected that only a part of loads collapses first, followed by collapse process of each load which did not go into instability during the preceding collapses. In such situations the over all equivalent collapse behavior viewed from bulk transmission level becomes somewhat different from the simple collapse driven by one aggregated induction machine. This paper studies the process of cascaded voltage collapse among many induction machines by time simulation, where load distribution on a feeder line is modeled by several hundreds of induction machines and static impedance loads. It is shown that in some cases voltage collapse really cascades among induction machines, where the macroscopic load dynamics viewed from upper voltage level makes slower collapse than expected by the aggregated load model. Also shown is the effects of machine protection of induction machines, which also makes slower collapse.
Radial transfer effects for poloidal rotation
Hallatschek, Klaus
2010-11-01
Radial transfer of energy or momentum is the principal agent responsible for radial structures of Geodesic Acoustic Modes (GAMs) or stationary Zonal Flows (ZF) generated by the turbulence. For the GAM, following a physical approach, it is possible to find useful expressions for the individual components of the Poynting flux or radial group velocity allowing predictions where a mathematical full analysis is unfeasible. Striking differences between up-down symmetric flux surfaces and asymmetric ones have been found. For divertor geometries, e.g., the direction of the propagation depends on the sign of the ion grad-B drift with respect to the X-point, reminiscent of a sensitive determinant of the H-mode threshold. In nonlocal turbulence computations it becomes obvious that the linear energy transfer terms can be completely overwhelmed by the action of the turbulence. In contrast, stationary ZFs are governed by the turbulent radial transfer of momentum. For sufficiently large systems, the Reynolds stress becomes a deterministic functional of the flows, which can be empirically determined from the stress response in computational turbulence studies. The functional allows predictions even on flow/turbulence states not readily obtainable from small amplitude noise, such as certain transport bifurcations or meta-stable states.
Stabe, R. G.; Whitney, W. J.; Moffitt, T. P.
1984-01-01
Experimental results are presented for a 0.767 scale model of the first stage of a two-stage turbine designed for a high by-pass ratio engine. The turbine was tested with both uniform inlet conditions and with an inlet radial temperature profile simulating engine conditions. The inlet temperature profile was essentially mixed-out in the rotor. There was also substantial underturning of the exit flow at the mean diameter. Both of these effects were attributed to strong secondary flows in the rotor blading. There were no significant differences in the stage performance with either inlet condition when differences in tip clearance were considered. Performance was very close to design intent in both cases.
Comparison of Design Methods for Axially Loaded Driven Piles in Cohesionless Soil
DEFF Research Database (Denmark)
Thomassen, Kristina; Andersen, Lars Vabbersgaard; Ibsen, Lars Bo
2012-01-01
For offshore wind turbines on deeper waters, a jacket sub-structure supported by axially loaded piles is thought to be the most suitable solution. The design method recommended by API and two CPT-based design methods are compared for two uniform sand profiles. The analysis show great difference...... in the predictions of bearing capacities calculated by means of the three methods for piles loaded in both tension and compression. This implies that further analysis of the bearing capacity of axially loaded piles in sand should be conducted....
Development of a VVER-1000 core loading pattern optimization program based on perturbation theory
International Nuclear Information System (INIS)
Hosseini, Mohammad; Vosoughi, Naser
2012-01-01
Highlights: ► We use perturbation theory to find an optimum fuel loading pattern in a VVER-1000. ► We provide a software for in-core fuel management optimization. ► We consider two objectives for our method (perturbation theory). ► We show that perturbation theory method is very fast and accurate for optimization. - Abstract: In-core nuclear fuel management is one of the most important concerns in the design of nuclear reactors. Two main goals in core fuel loading pattern design optimization are maximizing the core effective multiplication factor in order to extract the maximum energy, and keeping the local power peaking factor lower than a predetermined value to maintain the fuel integrity. Because of the numerous possible patterns of fuel assemblies in the reactor core, finding the best configuration is so important and challenging. Different techniques for optimization of fuel loading pattern in the reactor core have been introduced by now. In this study, a software is programmed in C language to find an order of the fuel loading pattern of a VVER-1000 reactor core using the perturbation theory. Our optimization method is based on minimizing the radial power peaking factor. The optimization process launches by considering an initial loading pattern and the specifications of the fuel assemblies which are given as the input of the software. The results on a typical VVER-1000 reactor reveal that the method could reach to a pattern with an allowed radial power peaking factor and increases the cycle length 1.1 days, as well.
Scaling laws for radial foil bearings
Honavara Prasad, Srikanth
The effects of fluid pressurization, structural deformation of the compliant members and heat generation in foil bearings make the design and analysis of foil bearings very complicated. The complex fluid-structural-thermal interactions in foil bearings also make modeling efforts challenging because these phenomena are governed by highly non-linear partial differential equations. Consequently, comparison of various bearing designs require detailed calculation of the flow fields (velocities, pressures), bump deflections (structural compliance) and heat transfer phenomena (viscous dissipation in the fluid, frictional heating, temperature profile etc.,) resulting in extensive computational effort (time/hardware). To obviate rigorous computations and aid in feasibility assessments of foil bearings of various sizes, NASA developed the "rule of thumb" design guidelines for estimation of journal bearing load capacity. The guidelines are based on extensive experimental data. The goal of the current work is the development of scaling laws for radial foil bearings to establish an analytical "rule of thumb" for bearing clearance and bump stiffness. The use of scale invariant Reynolds equation and experimentally observed NASA "rule of thumb" yield scale factors which can be deduced from first principles. Power-law relationships between: a. Bearing clearance and bearing radius, and b. bump stiffness and bearing radius, are obtained. The clearance and bump stiffness values obtained from scaling laws are used as inputs for Orbit simulation to study various cases. As the clearance of the bearing reaches the dimensions of the material surface roughness, asperity contact breaks the fluid film which results in wear. Similarly, as the rotor diameter increases (requiring larger bearing diameters), the load capacity of the fluid film should increase to prevent dry rubbing. This imposes limits on the size of the rotor diameter and consequently bearing diameter. Therefore, this thesis aims
Buckling of thin-walled beams under concentrated transverse loading
Menken, C.M.; Erp, van G.M.; Krupta, V.; Drdacky, M.
1991-01-01
The transversely loaded thin-walled beam under a non-uniform bending moment forms an example of the detrimental influence that a local effect may have on the overall behaviour. The local effect is the plate buckling in the region of maximum bending moment. The overall behaviour is the
Inertia effects in the laminar radial flow of a power law fluid with an electromagnetic field
International Nuclear Information System (INIS)
Chen, C.-K.; Chen, K.-H.; Wu, C.-Y.
1984-01-01
An approximate study of the pressure distribution for the radial flow of a non-newtonian (power law) fluid between two parallel disks in the presence of an axial electrical field is obtained by using the momentum and energy integral methods. For a non-newtonian fluid it is shown that the inertia effect must be considered to be significant for the pressure distribution, especially for the power law fluids with n >= 1. Furthermore, it is seen that the inertia effect will also lower the load capacity of the disks. (Auth.)
Anterior transposition of the radial nerve--a cadaveric study.
Yakkanti, Madhusudhan R; Roberts, Craig S; Murphy, Joshua; Acland, Robert D
2008-01-01
The radial nerve is at risk during the posterior plating of the humerus. The purpose of this anatomic study was to assess the extent of radial nerve dissection required for anterior transposition through the fracture site (transfracture anterior transposition). A cadaver study was conducted approaching the humerus by a posterior midline incision. The extent of dissection of the nerve necessary for plate fixation of the humerus fracture was measured. An osteotomy was created to model a humeral shaft fracture at the spiral groove (OTA classification 12-A2, 12-A3). The radial nerve was then transposed anterior to the humeral shaft through the fracture site. The additional dissection of the radial nerve and the extent of release of soft tissue from the humerus shaft to achieve the transposition were measured. Plating required a dissection of the radial nerve 1.78 cm proximal and 2.13 cm distal to the spiral groove. Transfracture anterior transposition of the radial nerve required an average dissection of 2.24 cm proximal and 2.68 cm distal to the spiral groove. The lateral intermuscular septum had to be released for 2.21 cm on the distal fragment to maintain laxity of the transposed nerve. Transfracture anterior transposition of the radial nerve before plating is feasible with dissection proximal and distal to the spiral groove and elevation of the lateral intermuscular septum. Potential clinical advantages of this technique include enhanced fracture site visualization, application of broader plates, and protection of the radial nerve during the internal fixation.
A New Filtering Algorithm Utilizing Radial Velocity Measurement
Institute of Scientific and Technical Information of China (English)
LIU Yan-feng; DU Zi-cheng; PAN Quan
2005-01-01
Pulse Doppler radar measurements consist of range, azimuth, elevation and radial velocity. Most of the radar tracking algorithms in engineering only utilize position measurement. The extended Kalman filter with radial velocity measureneut is presented, then a new filtering algorithm utilizing radial velocity measurement is proposed to improve tracking results and the theoretical analysis is also given. Simulation results of the new algorithm, converted measurement Kalman filter, extended Kalman filter are compared. The effectiveness of the new algorithm is verified by simulation results.
Latitudinal Dependence of the Radial IMF Component - Interplanetary Imprint
Suess, S. T.; Smith, E. J.; Phillips, J.; Goldstein, B. E.; Nerney, S.
1996-01-01
Ulysses measurements have confirmed that there is no significant gradient with respect to heliomagnetic latitude in the radial component, B(sub r,), of the interplanetary magnetic field. There are two processes responsible for this observation. In the corona, the plasma beta is much less than 1, except directly above streamers, so both longitudinal and latitudinal (meridional) gradients in field strength will relax, due to the transverse magnetic pressure gradient force, as the solar wind carries magnetic flux away from the Sun. This happens so quickly that the field is essentially uniform by 5 solar radius. Beyond 10 solar radius, beta is greater than 1 and it is possible for a meridional thermal pressure gradient to redistribute magnetic flux - an effect apparently absent in Ulysses and earlier ICE and Interplanetary Magnetic Physics (IMP) data. We discuss this second effect here, showing that its absence is mainly due to the perpendicular part of the anisotropic thermal pressure gradient in the interplanetary medium being too small to drive significant meridional transport between the Sun and approx. 4 AU. This is done using a linear analytic estimate of meridional transport. The first effect was discussed in an earlier paper.
Calculation and measurement of space charge in MV-size xxtruded cables systems under load conditions
Morshuis, P.H.F.; Bodega, R.; Fabiani, D.; Montanari, G.C.; Dissado, L.A.; Smit, J.J.
2007-01-01
A load current in dc high voltage cables results in a temperature drop across the insulation and hence a radial distribution of the insulation conductivity is found. Direct consequence is an accumulation of space charge in the bulk of the nsulation, that may significantly affect its reliability.
Photoelectric Radial Velocities, Paper XIX Additional Spectroscopic ...
Indian Academy of Sciences (India)
ian velocity curve that does justice to the measurements, but it cannot be expected to have much predictive power. Key words. Stars: late-type—stars: radial velocities—spectroscopic binaries—orbits. 0. Preamble. The 'Redman K stars' are a lot of seventh-magnitude K stars whose radial velocities were first observed by ...
Cally, Paul S.; Xiong, Ming
2018-01-01
Fast sausage modes in solar magnetic coronal loops are only fully contained in unrealistically short dense loops. Otherwise they are leaky, losing energy to their surrounds as outgoing waves. This causes any oscillation to decay exponentially in time. Simultaneous observations of both period and decay rate therefore reveal the eigenfrequency of the observed mode, and potentially insight into the tubes’ nonuniform internal structure. In this article, a global spectral description of the oscillations is presented that results in an implicit matrix eigenvalue equation where the eigenvalues are associated predominantly with the diagonal terms of the matrix. The off-diagonal terms vanish identically if the tube is uniform. A linearized perturbation approach, applied with respect to a uniform reference model, is developed that makes the eigenvalues explicit. The implicit eigenvalue problem is easily solved numerically though, and it is shown that knowledge of the real and imaginary parts of the eigenfrequency is sufficient to determine the width and density contrast of a boundary layer over which the tubes’ enhanced internal densities drop to ambient values. Linearized density kernels are developed that show sensitivity only to the extreme outside of the loops for radial fundamental modes, especially for small density enhancements, with no sensitivity to the core. Higher radial harmonics do show some internal sensitivity, but these will be more difficult to observe. Only kink modes are sensitive to the tube centres. Variation in internal and external Alfvén speed along the loop is shown to have little effect on the fundamental dimensionless eigenfrequency, though the associated eigenfunction becomes more compact at the loop apex as stratification increases, or may even displace from the apex.
Linear theory radial and nonradial pulsations of DA dwarf stars
International Nuclear Information System (INIS)
Starrfield, S.; Cox, A.N.; Hodson, S.; Pesnell, W.D.
1982-01-01
The Los Alamos stellar envelope and radial linear non-adiabatic computer code, along with a new Los Alamos non-radial code are used to investigate the total hydrogen mass necessary to produce the non-radial instability of DA dwarfs
Radial and azimuthal distribution of Io's oxygen neutral cloud observed by Hisaki/EXCEED
Koga, R.; Tsuchiya, F.; Kagitani, M.; Sakanoi, T.; Yoneda, M.; Yoshikawa, I.; Yoshioka, K.; Murakami, G.; Yamazaki, A.; Kimura, T.; Smith, H. T.
2017-12-01
We report the spatial distributions of oxygen neural cloud surrounding Jupiter's moon Io and along Io's orbit observed by the HISAKI satellite. Atomic oxygen and sulfur in Io's atmosphere escape from the exobase and move to corona ( 5.8 Io radii) mainly due to atmospheric sputtering. Io plasma torus is formed by ionization of these atoms by electron impact and charge exchange processes. It is essential to examine the dominant source of Io plasma torus, particularly in the vicinity of Io (5.8 Io radii; extended neutral clouds). The spatial distribution of oxygen and sulfur neutral clouds is important to understand the source. The extreme ultraviolet spectrometer called EXCEED (Extreme Ultraviolet Spectroscope for Exospheric Dynamics) installed on the Hisaki satellite observed Io plasma torus continuously in 2014-2015, and we carried out the monitoring of the distribution of atomic oxygen emission at 130.4 nm. The emission averaged over the distance range of 4.5-6.5 Jovian radii on the dawn and dusk sides strongly depends on the Io phase angle (IPA), and has a emission peak between IPA of 60-90 degrees on the dawn side, and between 240-270 degrees on the dusk side, respectively. It also shows the asymmetry with respect to Io's position: the intensity averaged for IPA 60-90 degrees (13.3 Rayleighs (R)) is 1.2 times greater than that for IPA 90-120 degrees (11.1 R) on the dawn side. The similar tendency is found on the dusk side. Weak atomic oxygen emission (4 R) uniformly distributes in every IPA. We also examined the radial distribution of the oxygen neutral cloud during the same period and found the emission peak near Io's orbit with decreasing the intensity toward 8.0 Jupiter radii. The results show the high density component of the oxygen neutral cloud is concentrated around Io and extends mainly toward leading side of Io. In addition, the low density neutrals uniformly exist along Io's orbit. Both components extend radially outward up to 8 Jovian radii with
CHF multiplier of subcooled flow boiling for non-uniform heating conditions in swirl tube
International Nuclear Information System (INIS)
Inasaka, F.; Nariai, H.
1994-01-01
The high heat flux components of fusion reactors, such as divertor plates and beam dumps of neutral beam injectors, are estimated to be subjected to very high heat loads more than 10 MW/m 2 . Critical heat flux (CHF), which determines the upper limit of heat removal, is one of the most important problems in designing cooling systems. For practical applications in cooling systems, subcooled flow boiling in water combined with swirl-flow in tubes with internal twisted tape is thought to be the most superior for CHF characteristics in fusion reactor components, heat by irradiation comes in from one side of the wall, and cooling channel is then under circumferentially non-uniform heating condition. Authors have conducted the experiments on the CHF with internal twisted tapes under circumferentially non-uniform heating conditions and showed that when the intensity of non-uniformity increased, q cH (peak heat flux at burnout under nonuniform heating condition) in tube with internal twisted tape increased above the q c,unif (CHF under uniform heating condition), though the average qualities were the same for both cases. They also showed that this CHF enhancement was not seen in smooth tubes without tape under the same average qualities
Synthetic approaches to uniform polymers.
Ali, Monzur; Brocchini, Steve
2006-12-30
Uniform polymers are characterised by a narrow molecular weight distribution (MWD). Uniformity is also defined by chemical structure in respect of (1) monomer orientation, sequence and stereo-regularity, (2) polymer shape and morphology and (3) chemical functionality. The function of natural polymers such as polypeptides and polynucleotides is related to their conformational structure (e.g. folded tertiary structure). This is only possible because of their high degree of uniformity. While completely uniform synthetic polymers are rare, polymers with broad structure and MWD are widely used in medicine and the biomedical sciences. They are integral components in final dosage forms, drug delivery systems (DDS) and in implantable devices. Increasingly uniform polymers are being used to develop more complex medicines (e.g. delivery of biopharmaceuticals, enhanced formulations or DDS's for existing actives). In addition to the function imparted by any new polymer it will be required to meet stringent specifications in terms of cost containment, scalability, biocompatibility and performance. Synthetic polymers with therapeutic activity are also being developed to exploit their polyvalent properties, which is not possible with low molecular weight molecules. There is need to utilise uniform polymers for applications where the polymer may interact with the systemic circulation, tissues or cellular environment. There are also potential applications (e.g. stimuli responsive coatings) where uniform polymers may be used for their more defined property profile. While it is not yet practical to prepare synthetic polymers to the same high degree of uniformity as proteins, nature also effectively utilises many polymers with lower degrees of uniformity (e.g. polysaccharides, poly(amino acids), polyhydroxyalkanoates). In recent years it has become possible to prepare with practical experimental protocols sufficient quantities of polymers that display many aspects of uniformity. This
Assessment of Wind Parameter Sensitivity on Extreme and Fatigue Wind Turbine Loads
Energy Technology Data Exchange (ETDEWEB)
Robertson, Amy N [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Sethuraman, Latha [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Jonkman, Jason [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Quick, Julian [National Renewable Energy Laboratory (NREL), Golden, CO (United States)
2018-01-12
Wind turbines are designed using a set of simulations to ascertain the structural loads that the turbine could encounter. While mean hub-height wind speed is considered to vary, other wind parameters such as turbulence spectra, sheer, veer, spatial coherence, and component correlation are fixed or conditional values that, in reality, could have different characteristics at different sites and have a significant effect on the resulting loads. This paper therefore seeks to assess the sensitivity of different wind parameters on the resulting ultimate and fatigue loads on the turbine during normal operational conditions. Eighteen different wind parameters are screened using an Elementary Effects approach with radial points. As expected, the results show a high sensitivity of the loads to the turbulence standard deviation in the primary wind direction, but the sensitivity to wind shear is often much greater. To a lesser extent, other wind parameters that drive loads include the coherence in the primary wind direction and veer.
Flow performance of highly loaded axial fan with bowed rotor blades
International Nuclear Information System (INIS)
Chen, L; Liu, X J; Yang, A L; Dai, R
2013-01-01
In this paper, a partial bowed rotor blade was proposed for a newly designed high loaded axial fan. The blade was positively bowed 30 degrees from hub to 30 percent spanwise position. Flows of radial blade and bowed blade fans were numerically compared for various operation conditions. Results show that the fan's performance is improved. At the designed condition with flow coefficient of 0.52, the efficiency of the bowed blade fan is increased 1.44% and the static pressure rise is increased 11%. Comparing the flow structures, it can be found that the separated flow in the bowed fan is reduced and confined within 20 percent span, which is less than the 35 percent in the radial fan. It means that the bowed blade generates negative blade force and counteracts partial centrifugal force. It is alleviates the radial movements of boundary layers in fan's hub region. Flow losses due to 3D mixing are reduced in the rotor. Inlet flow to downstream stator is also improved
Clem, Michelle M.; Woike, Mark R.; Abdul-Aziz, Ali
2014-01-01
The Aeronautical Sciences Project under NASA's Fundamental Aeronautics Program is interested in the development of novel measurement technologies, such as optical surface measurements for the in situ health monitoring of critical constituents of the internal flow path. In situ health monitoring has the potential to detect flaws, i.e. cracks in key components, such as engine turbine disks, before the flaws lead to catastrophic failure. The present study, aims to further validate and develop an optical strain measurement technique to measure the radial growth and strain field of an already cracked disk, mimicking the geometry of a sub-scale turbine engine disk, under loaded conditions in the NASA Glenn Research Center's High Precision Rotordynamics Laboratory. The technique offers potential fault detection by imaging an applied high-contrast random speckle pattern under unloaded and loaded conditions with a CCD camera. Spinning the cracked disk at high speeds (loaded conditions) induces an external load, resulting in a radial growth of the disk of approximately 50.0-µm in the flawed region and hence, a localized strain field. When imaging the cracked disk under static conditions, the disk will be undistorted; however, during rotation the cracked region will grow radially, thus causing the applied particle pattern to be 'shifted'. The resulting particle displacements between the two images is measured using the two-dimensional cross-correlation algorithms implemented in standard Particle Image Velocimetry (PIV) software to track the disk growth, which facilitates calculation of the localized strain field. A random particle distribution is adhered onto the surface of the cracked disk and two bench top experiments are carried out to evaluate the technique's ability to measure the induced particle displacements. The disk is shifted manually using a translation stage equipped with a fine micrometer and a hotplate is used to induce thermal growth of the disk, causing the
Modelling cell cycle synchronisation in networks of coupled radial glial cells.
Barrack, Duncan S; Thul, Rüdiger; Owen, Markus R
2015-07-21
Radial glial cells play a crucial role in the embryonic mammalian brain. Their proliferation is thought to be controlled, in part, by ATP mediated calcium signals. It has been hypothesised that these signals act to locally synchronise cell cycles, so that clusters of cells proliferate together, shedding daughter cells in uniform sheets. In this paper we investigate this cell cycle synchronisation by taking an ordinary differential equation model that couples the dynamics of intracellular calcium and the cell cycle and extend it to populations of cells coupled via extracellular ATP signals. Through bifurcation analysis we show that although ATP mediated calcium release can lead to cell cycle synchronisation, a number of other asynchronous oscillatory solutions including torus solutions dominate the parameter space and cell cycle synchronisation is far from guaranteed. Despite this, numerical results indicate that the transient and not the asymptotic behaviour of the system is important in accounting for cell cycle synchronisation. In particular, quiescent cells can be entrained on to the cell cycle via ATP mediated calcium signals initiated by a driving cell and crucially will cycle in near synchrony with the driving cell for the duration of neurogenesis. This behaviour is highly sensitive to the timing of ATP release, with release at the G1/S phase transition of the cell cycle far more likely to lead to near synchrony than release during mid G1 phase. This result, which suggests that ATP release timing is critical to radial glia cell cycle synchronisation, may help us to understand normal and pathological brain development. Copyright © 2015 Elsevier Ltd. All rights reserved.
Fracture of thermally loaded disks of materials in elastic-brittle state
International Nuclear Information System (INIS)
Egorov, V.S.; Lanin, A.G.; Fedik, I.I.
1981-01-01
Fracture kinetics and limiting supporting power were studied in a solid thin disk axisymmetrically cooled from the periphery depending on the deqree of the stressed state nonuniformity and crack interaction. Basing on a strength approach of fracture linear mechanism it has become possible to obtain limit equilibrium curves and to evaluate thermoelastic stress redistribution on the boundary of the disk with one, two and four symmetrical radial cracks. Calculated data are confirmed by the results of the experiments performed with zirconium carbide water-cooled disks. It is shown that while determining the limit supporting power of a thermally loaded body, the loading history and fracture kinetics should be taken into account
Reactor core and initially loaded reactor core of nuclear reactor
International Nuclear Information System (INIS)
Koyama, Jun-ichi; Aoyama, Motoo.
1989-01-01
In BWR type reactors, improvement for the reactor shutdown margin is an important characteristic condition togehter with power distribution flattening . However, in the reactor core at high burnup degree, the reactor shutdown margin is different depending on the radial position of the reactor core. That is , the reactor shutdown margin is smaller in the outer peripheral region than in the central region of the reactor core. In view of the above, the reactor core is divided radially into a central region and as outer region. The amount of fissionable material of first fuel assemblies newly loaded in the outer region is made less than the amount of the fissionable material of second fuel assemblies newly loaded in the central region, to thereby improve the reactor shutdown margin in the outer region. Further, the ratio between the amount of the fissionable material in the upper region and that of the fissionable material in the lower portion of the first fuel assemblies is made smaller than the ratio between the amount of the fissionable material in the upper region and that of the fissionable material in the lower region of the second fuel assemblies, to thereby obtain a sufficient thermal margin in the central region. (K.M.)
A new meshless approach to map electromagnetic loads for FEM analysis on DEMO TF coil system
International Nuclear Information System (INIS)
Biancolini, Marco Evangelos; Brutti, Carlo; Giorgetti, Francesco; Muzzi, Luigi; Turtù, Simonetta; Anemona, Alessandro
2015-01-01
Graphical abstract: - Highlights: • Generation and mapping of magnetic load on DEMO using radial basis function. • Good agreement between RBF interpolation and EM TOSCA computations. • Resultant forces are stable with respect to the target mesh used. • Stress results are robust and accurate even if a coarse cloud is used for RBF interpolation. - Abstract: Demonstration fusion reactors (DEMO) are being envisaged to be able to produce commercial electrical power. The design of the DEMO magnets and of the constituting conductors is a crucial issue in the overall engineering design of such a large fusion machine. In the frame of the EU roadmap of the so-called fast track approach, mechanical studies of preliminary DEMO toroidal field (TF) coil system conceptual designs are being enforced. The magnetic field load acting on the DEMO TF coil conductor has to be evaluated as input in the FEM model mesh, in order to evaluate the stresses on the mechanical structure. To gain flexibility, a novel approach based on the meshless method of radial basis functions (RBF) has been implemented. The present paper describes this original and flexible approach for the generation and mapping of magnetic load on DEMO TF coil system.
Atomistic simulation of fcc—bcc phase transition in single crystal Al under uniform compression
International Nuclear Information System (INIS)
Li Li; Liang Jiu-Qing; Shao Jian-Li; Duan Su-Qing; Li Yan-Fang
2012-01-01
By molecular dynamics simulations employing an embedded atom model potential, we investigate the fcc-to-bcc phase transition in single crystal Al, caused by uniform compression. Results show that the fcc structure is unstable when the pressure is over 250 GPa, in reasonable agreement with the calculated value through the density functional theory. The morphology evolution of the structural transition and the corresponding transition mechanism are analysed in detail. The bcc (011) planes are transited from the fcc (111-bar) plane and the (11-bar1) plane. We suggest that the transition mechanism consists mainly of compression, shear, slid and rotation of the lattice. In addition, our radial distribution function analysis explicitly indicates the phase transition of Al from fcc phase to bcc structure. (condensed matter: structural, mechanical, and thermal properties)
Approximate analysis of rigid plate loading on elastic multi-layered systems
CSIR Research Space (South Africa)
Maina, JW
2008-07-01
Full Text Available , this distribution was approximated using uniformly distributed multiple loads and analysis performed using Games. Results have shown good agreement with the theory for the case of a semi-infinite medium. Furthermore, extension of this method to multilayered system...
Directory of Open Access Journals (Sweden)
Jafar Jallad
2018-05-01
Full Text Available In a radial distribution network integrated with distributed generation (DG, frequency and voltage instability could occur due to grid disconnection, which would result in an islanded network. This paper proposes an optimal load shedding scheme to balance the electricity demand and the generated power of DGs. The integration of the Firefly Algorithm and Particle Swarm Optimization (FAPSO is proposed for the application of the planned load shedding and under frequency load shedding (UFLS scheme. In planning mode, the hybrid optimization maximizes the amount of load remaining and improves the voltage profile of load buses within allowable limits. Moreover, the hybrid optimization can be used in UFLS scheme to identify the optimal combination of loads that need to be shed from a network in operation mode. In order to assess the capabilities of the hybrid optimization, the IEEE 33-bus radial distribution system and part of the Malaysian distribution network with different types of DGs were used. The response of the proposed optimization method in planning and operation were compared with other optimization techniques. The simulation results confirmed the effectiveness of the proposed hybrid optimization in planning mode and demonstrated that the proposed UFLS scheme is quick enough to restore the system frequency without overshooting in less execution time.
A Technique for Temperature and Ultimate Load Calculations of Thin Targets in a Pulsed Electron Beam
DEFF Research Database (Denmark)
Hansen, Jørgen-Walther; Lundsager, Per
1979-01-01
A technique is presented for the calculation of transient temperature distributions and ultimate load of rotationally symmetric thin membranes with uniform lateral load and exposed to a pulsed electron beam from a linear accelerator. Heat transfer by conduction is considered the only transfer...... mechanism. The ultimate load is calculated on the basis of large plastic strain analysis. Analysis of one aluminum and one titanium membrane is shown....
Effect of the radial electric field on turbulence
International Nuclear Information System (INIS)
Carreras, B.A.; Lynch, V.E.
1990-01-01
For many years, the neoclassical transport theory for three- dimensional magnetic configurations, such as magnetic mirrors, ELMO Bumpy Tori (EBTs), and stellarators, has recognized the critical role of the radial electric field in the confinement. It was in these confinement devices that the first experimental measurements of the radial electric field were made and correlated with confinement losses. In tokamaks, the axisymmetry implies that the neoclassical fluxes are ambipolar and, as a consequence, independent of the radial electric field. However, axisymmetry is not strict in a tokamak with turbulent fluctuations, and near the limiter ambipolarity clearly breaks down. Therefore, the question of the effect of the radial electric field on tokamak confinement has been raised in recent years. In particular, the radial electric field has been proposed to explain the transition from L-mode to H-mode confinement. There is some initial experimental evidence supporting this type of explanation, although there is not yet a self-consistent theory explaining the generation of the electric field and its effect on the transport. Here, a brief review of recent results is presented. 27 refs., 4 figs
A user's evaluation of radial flow HEPA filters
International Nuclear Information System (INIS)
Purcell, J.A.
1992-07-01
High efficiency particulate air (HEPA) filters of rectangular cross section have been used to remove particulates and the associated radioactivity from air ventilation streams since the advent of nuclear materials processing. Use of round axial flow HEPA filters is also longstanding. The advantages of radial flow filters in a circular configuration have been well demonstrated in UKAEA during the last 5--7 years. An evaluation of radial flow filters for fissile process gloveboxes reveals several substantial benefits in addition to the advantages claimed in UKAEA Facilities. The radial flow filter may be provided in a favorable geometry resulting in improved criticality safety. The filter configuration lends to in-place testing at the glovebox to exhaust duct interface. This will achieve compliance with DOE Order 6430.1A, Section 99.0.2. Preliminary testing at SRS for radial flow filters manufactured by Flanders Filters, Inc. revealed compliance in all the usual specifications for filtration efficiency, pressure differential and materials of construction. An evaluation, further detailed in this report, indicates that the radial flow HEPA filter should be considered for inclusion in new ventilation system designs
Radial extension of drift waves in presence of velocity profiles
International Nuclear Information System (INIS)
Sen, S.; Weiland, J.
1994-01-01
The effect of a radially varying poloidal velocity field on the recently found radially extended toroidal drift waves is investigated analytically. The role of velocity curvature (υ φ '') is found to have robust effects on the radial model structure of the mode. For a positive value of the curvature (Usually found in the H-mode edges) the radial model envelope, similar to the sheared slab case, becomes fully outgoing. The mode is therefore stable. On the other hand, for a negative value of the curvature (usually observed in the L-mode edges) all the characteristics of conventional drift waves return back. The radial mode envelope reduces to a localized Gaussian shape and the mode is therefore unstable again for typical (magnetic) shear values in tokamaks. Velocity shear (υ φ ??) on the other hand is found to have rather insignificant role both in determining the radial model structure and stability
Tackling optimization challenges in industrial load control and full-duplex radios
Gholian, Armen
In price-based demand response programs in smart grid, utilities set the price in accordance with the grid operating conditions and consumers respond to price signals by conducting optimal load control to minimize their energy expenditure while satisfying their energy needs. Industrial sector consumes a large portion of world electricity and addressing optimal load control of energy-intensive industrial complexes, such as steel industry and oil-refinery, is of practical importance. Formulating a general industrial complex and addressing issues in optimal industrial load control in smart grid is the focus of the second part of this dissertation. Several industrial load details are considered in the proposed formulation, including those that do not appear in residential or commercial load control problems. Operation under different smart pricing scenarios, namely, day-ahead pricing, time-of-use pricing, peak pricing, inclining block rates, and critical peak pricing are considered. The use of behind-the-meter renewable generation and energy storage is also considered. The formulated optimization problem is originally nonlinear and nonconvex and thus hard to solve. However, it is then reformulated into a tractable linear mixed-integer program. The performance of the design is assessed through various simulations for an oil refinery and a steel mini-mill. In the third part of this dissertation, a novel all-analog RF interference canceler is proposed. Radio self-interference cancellation (SIC) is the fundamental enabler for full-duplex radios. While SIC methods based on baseband digital signal processing and/or beamforming are inadequate, an all-analog method is useful to drastically reduce the self-interference as the first stage of SIC. It is shown that a uniform architecture with uniformly distributed RF attenuators has a performance highly dependent on the carrier frequency. It is also shown that a new architecture with the attenuators distributed in a clustered
Hanna, Elias B; Mogabgab, Owen N; Baydoun, Hassan
2018-01-01
We present cases of complex, calcified iliac occlusive disease revascularized via a combined radial-femoral access strategy. Through a 6-French, 125-cm transradial guiding catheter, antegrade guidewires and catheters are advanced into the iliac occlusion, while retrograde devices are advanced transfemorally. The transradial and transfemoral channels communicate, allowing the devices to cross the occlusion into the true lumen (radial-femoral antegrade-retrograde rendezvous).
A Novel Analytical Technique for Optimal Allocation of Capacitors in Radial Distribution Systems
Directory of Open Access Journals (Sweden)
Sarfaraz Nawaz
2017-07-01
Full Text Available In this paper, a novel analytical technique is proposed to determine the optimal size and location of shunt capacitor units in radial distribution systems. An objective function is formulated to reduce real power loss, to improve the voltage profile and to increase annual cost savings. A new constant, the Loss Sensitivity Constant (LSC, is proposed here. The value of LSC decides the location and size of candidate buses. The technique is demonstrated on an IEEE-33 bus system at different load levels and the 130-bus distribution system of Jamawa Ramgarh village, Jaipur city. The obtained results are compared with the latest optimization techniques to show the effectiveness and robustness of the proposed technique.
Becerril, L.; Galindo, I.; Martí, J.; Gudmundsson, A.
2015-04-01
Using new surface structural data as well as subsurface structural data obtained from seventeen water galleries, we provide a comprehensive model of the volcano-tectonic evolution of El Hierro (Canary Islands). We have identified, measured and analysed more than 1700 volcano-structural elements including vents, eruptive fissures, dykes and faults. The new data provide important information on the main structural patterns of the island and on its stress and strain fields, all of which are crucial for reliable hazard assessments. We conducted temporal and spatial analyses of the main structural elements, focusing on their relative age and association with the three main cycles in the construction of the island: the Tiñor Edifice, the El Golfo-Las Playas Edifice, and the Rift Volcanism. A radial strike distribution, which can be related to constructive episodes, is observed in the on-land structures. A similar strike distribution is seen in the submarine eruptive fissures, which are radial with respect to the centre of the island. However, the volcano-structural elements identified onshore and reflecting the entire volcano-tectonic evolution of the island also show a predominant NE-SW strike, which coincides with the main regional trend of the Canary archipelago as a whole. Two other dominant directions of structural elements, N-S and WNW-ESE, are evident from the establishment of the El Golfo-Las Playas edifice, during the second constructive cycle. We suggest that the radial-striking structures reflect comparatively uniform stress fields during the constructive episodes, mainly conditioned by the combination of overburden pressure, gravitational spreading, and magma-induced stresses in each of the volcanic edifices. By contrast, in the shallower parts of the edifice the NE-SW, N-S and WNW-ESE-striking structures reflect local stress fields related to the formation of mega-landslides and masking the general and regional radial patterns.
A novel structure of permanent-magnet-biased radial hybrid magnetic bearing
International Nuclear Information System (INIS)
Sun Jinji; Fang Jiancheng
2011-01-01
The paper proposes a novel structure for a permanent-magnet-biased radial hybrid magnetic bearing. Based on the air gap between the rotor and stator of traditional radial hybrid magnetic bearings, a subsidiary air gap is first constructed between the permanent magnets and the inner magnetic parts. Radial magnetic bearing makes X and Y magnetic fields independent of each other with separate stator poles, and the subsidiary air gap makes control flux to a close loop. As a result, magnetic field coupling of the X and Y channels is decreased significantly by the radial hybrid magnetic bearing and makes it easier to design control systems. Then an external rotor structure is designed into the radial hybrid magnetic bearing. The working principle of the radial hybrid magnetic bearing and its mathematical model is discussed. Finally, a non-linear magnetic network method is proposed to analyze the radial hybrid magnetic bearing. Simulation results indicate that magnetic fields in the two channels of the proposed radial hybrid magnetic bearing decouple well from each other.
A novel structure of permanent-magnet-biased radial hybrid magnetic bearing
Energy Technology Data Exchange (ETDEWEB)
Sun Jinji, E-mail: sunjinji@aspe.buaa.edu.c [Key Laboratory of Fundamental Science for National Defense, Novel Inertial Instrument and Navigation System Technology, School of Instrument Science and Opto-electronics Engineering, Beijing University of Aeronautics and Astronautics, 100191 (China); Fang Jiancheng [Key Laboratory of Fundamental Science for National Defense, Novel Inertial Instrument and Navigation System Technology, School of Instrument Science and Opto-electronics Engineering, Beijing University of Aeronautics and Astronautics, 100191 (China)
2011-01-15
The paper proposes a novel structure for a permanent-magnet-biased radial hybrid magnetic bearing. Based on the air gap between the rotor and stator of traditional radial hybrid magnetic bearings, a subsidiary air gap is first constructed between the permanent magnets and the inner magnetic parts. Radial magnetic bearing makes X and Y magnetic fields independent of each other with separate stator poles, and the subsidiary air gap makes control flux to a close loop. As a result, magnetic field coupling of the X and Y channels is decreased significantly by the radial hybrid magnetic bearing and makes it easier to design control systems. Then an external rotor structure is designed into the radial hybrid magnetic bearing. The working principle of the radial hybrid magnetic bearing and its mathematical model is discussed. Finally, a non-linear magnetic network method is proposed to analyze the radial hybrid magnetic bearing. Simulation results indicate that magnetic fields in the two channels of the proposed radial hybrid magnetic bearing decouple well from each other.
Detonation in supersonic radial outflow
Kasimov, Aslan R.
2014-11-07
We report on the structure and dynamics of gaseous detonation stabilized in a supersonic flow emanating radially from a central source. The steady-state solutions are computed and their range of existence is investigated. Two-dimensional simulations are carried out in order to explore the stability of the steady-state solutions. It is found that both collapsing and expanding two-dimensional cellular detonations exist. The latter can be stabilized by putting several rigid obstacles in the flow downstream of the steady-state sonic locus. The problem of initiation of standing detonation stabilized in the radial flow is also investigated numerically. © 2014 Cambridge University Press.
Elongated dust clouds in a uniform DC positive column of low pressure gas discharge
International Nuclear Information System (INIS)
Usachev, A D; Zobnin, A V; Petrov, O F; Fortov, V E; Thoma, M H; Pustylnik, M Y; Fink, M A; Morfill, G E
2016-01-01
Experimental investigations of the formation of elongated dust clouds and their influence on the plasma glow intensity of the uniform direct current (DC) positive column (PC) have been performed under microgravity conditions. For the axial stabilization of the dust cloud position a polarity switching DC gas discharge with a switching frequency of 250 Hz was used. During the experiment, a spontaneous division of one elongated dust cloud into two smaller steady state dust clouds has been observed. Quantitative data on the dust cloud shape, size and dust number density distribution were obtained. Axial and radial distributions of plasma emission within the 585.2 nm and 703.2 nm neon spectral lines were measured over the whole discharge volume. It has been found that both spectral line intensities at the dust cloud region grew 1.7 times with respect to the undisturbed positive column region; in this the 585.2 nm line intensity increased by 10% compared to the 703.2 nm line intensity. For a semi-quantitative explanation of the observed phenomena the Schottky approach based on the equation of diffusion was used. The model reasonably explains the observed glow enhancement as an increasing of the ionization rate in the discharge with dust cloud, which compensates ion-electron recombination on the dust grain surfaces. In this, the ionization rate increases due to the growing of the DC axial electric field, and the glow grows directly proportional to the electric field. It is shown that the fundamental condition of the radial stability of the dusty plasma cloud is equal to the ionization and recombination rates within the cloud volume that is possible only when the electron density is constant and the radial electric field is absent within the dust cloud. (paper)
Radial nerve dysfunction (image)
The radial nerve travels down the arm and supplies movement to the triceps muscle at the back of the upper arm. ... the wrist and hand. The usual causes of nerve dysfunction are direct trauma, prolonged pressure on the ...
Improving prediction accuracy of cooling load using EMD, PSR and RBFNN
Shen, Limin; Wen, Yuanmei; Li, Xiaohong
2017-08-01
To increase the accuracy for the prediction of cooling load demand, this work presents an EMD (empirical mode decomposition)-PSR (phase space reconstruction) based RBFNN (radial basis function neural networks) method. Firstly, analyzed the chaotic nature of the real cooling load demand, transformed the non-stationary cooling load historical data into several stationary intrinsic mode functions (IMFs) by using EMD. Secondly, compared the RBFNN prediction accuracies of each IMFs and proposed an IMF combining scheme that is combine the lower-frequency components (called IMF4-IMF6 combined) while keep the higher frequency component (IMF1, IMF2, IMF3) and the residual unchanged. Thirdly, reconstruct phase space for each combined components separately, process the highest frequency component (IMF1) by differential method and predict with RBFNN in the reconstructed phase spaces. Real cooling load data of a centralized ice storage cooling systems in Guangzhou are used for simulation. The results show that the proposed hybrid method outperforms the traditional methods.
Variable stator radial turbine
Rogo, C.; Hajek, T.; Chen, A. G.
1984-01-01
A radial turbine stage with a variable area nozzle was investigated. A high work capacity turbine design with a known high performance base was modified to accept a fixed vane stagger angle moveable sidewall nozzle. The nozzle area was varied by moving the forward and rearward sidewalls. Diffusing and accelerating rotor inlet ramps were evaluated in combinations with hub and shroud rotor exit rings. Performance of contoured sidewalls and the location of the sidewall split line with respect to the rotor inlet was compared to the baseline. Performance and rotor exit survey data are presented for 31 different geometries. Detail survey data at the nozzle exit are given in contour plot format for five configurations. A data base is provided for a variable geometry concept that is a viable alternative to the more common pivoted vane variable geometry radial turbine.
Dynamic intelligent cleaning model of dirty electric load data
International Nuclear Information System (INIS)
Zhang Xiaoxing; Sun Caixin
2008-01-01
There are a number of dirty data in the load database derived from the supervisory control and data acquisition (SCADA) system. Thus, the data must be carefully and reasonably adjusted before it is used for electric load forecasting or power system analysis. This paper proposes a dynamic and intelligent data cleaning model based on data mining theory. Firstly, on the basis of fuzzy soft clustering, the Kohonen clustering network is improved to fulfill the parallel calculation of fuzzy c-means soft clustering. Then, the proposed dynamic algorithm can automatically find the new clustering center (the characteristic curve of the data) with the updated sample data; At last, it is composed with radial basis function neural network (RBFNN), and then, an intelligent adjusting model is proposed to identify the dirty data. The rapid and dynamic performance of the model makes it suitable for real time calculation, and the efficiency and accuracy of the model is proved by test results of electrical load data analysis in Chongqing
Self-organized dynamics in local load-sharing fiber bundle models.
Biswas, Soumyajyoti; Chakrabarti, Bikas K
2013-10-01
We study the dynamics of a local load-sharing fiber bundle model in two dimensions under an external load (which increases with time at a fixed slow rate) applied at a single point. Due to the local load-sharing nature, the redistributed load remains localized along the boundary of the broken patch. The system then goes to a self-organized state with a stationary average value of load per fiber along the (increasing) boundary of the broken patch (damaged region) and a scale-free distribution of avalanche sizes and other related quantities are observed. In particular, when the load redistribution is only among nearest surviving fiber(s), the numerical estimates of the exponent values are comparable with those of the Manna model. When the load redistribution is uniform along the patch boundary, the model shows a simple mean-field limit of this self-organizing critical behavior, for which we give analytical estimates of the saturation load per fiber values and avalanche size distribution exponent. These are in good agreement with numerical simulation results.
46 CFR 310.11 - Cadet uniforms.
2010-10-01
... for State, Territorial or Regional Maritime Academies and Colleges § 310.11 Cadet uniforms. Cadet uniforms shall be supplied at the school in accordance with the uniform regulations of the School. Those... 46 Shipping 8 2010-10-01 2010-10-01 false Cadet uniforms. 310.11 Section 310.11 Shipping MARITIME...
Radial-probe EBUS for the diagnosis of peripheral pulmonary lesions
Directory of Open Access Journals (Sweden)
Marcia Jacomelli
Full Text Available ABSTRACT Objective: Conventional bronchoscopy has a low diagnostic yield for peripheral pulmonary lesions. Radial-probe EBUS employs a rotating ultrasound transducer at the end of a probe that is passed through the working channel of the bronchoscope. Radial-probe EBUS facilitates the localization of peripheral pulmonary nodules, thus increasing the diagnostic yield. The objective of this study was to present our initial experience using radial-probe EBUS in the diagnosis of peripheral pulmonary lesions at a tertiary hospital. Methods: We conducted a retrospective analysis of 54 patients who underwent radial-probe EBUS-guided bronchoscopy for the investigation of pulmonary nodules or masses between February of 2012 and September of 2013. Radial-probe EBUS was performed with a flexible 20-MHz probe, which was passed through the working channel of the bronchoscope and advanced through the bronchus to the target lesion. For localization of the lesion and for collection procedures (bronchial brushing, transbronchial needle aspiration, and transbronchial biopsy, we used fluoroscopy. Results: Radial-probe EBUS identified 39 nodules (mean diameter, 1.9 ± 0.7 cm and 19 masses (mean diameter, 4.1 ± 0.9 cm. The overall sensitivity of the method was 66.7% (79.5% and 25.0%, respectively, for lesions that were visible and not visible by radial-probe EBUS. Among the lesions that were visible by radial-probe EBUS, the sensitivity was 91.7% for masses and 74.1% for nodules. The complications were pneumothorax (in 3.7% and bronchial bleeding, which was controlled bronchoscopically (in 9.3%. Conclusions: Radial-probe EBUS shows a good safety profile, a low complication rate, and high sensitivity for the diagnosis of peripheral pulmonary lesions.
Sharp Dissection versus Electrocautery for Radial Artery Harvesting
Marzban, Mehrab; Arya, Reza; Mandegar, Mohammad Hossein; Karimi, Abbas Ali; Abbasi, Kiomars; Movahed, Namvar; Abbasi, Seyed Hesameddin
2006-01-01
Radial arteries have been increasingly used during the last decade as conduits for coronary artery revascularization. Although various harvesting techniques have been described, there has been little comparative study of arterial damage and patency. A radial artery graft was used in 44 consecutive patients, who were randomly divided into 2 groups. In the 1st group, the radial artery was harvested by sharp dissection and in the 2nd, by electrocautery. These groups were compared with regard to radial artery free flow, harvest time, number of clips used, complications, and endothelial damage. Radial artery free flow before and after intraluminal administration of papaverine was significantly greater in the electrocautery group (84.3 ± 50.7 mL/min and 109.7 ± 68.5 mL/min) than in the sharp-dissection group (52.9 ± 18.3 mL/min and 69.6 ± 28.2 mL/ min) (P =0.003). Harvesting time by electrocautery was significantly shorter (25.4 ± 4.3 min vs 34.4 ± 5.9 min) (P =0.0001). Electrocautery consumed an average of 9.76 clips, versus 22.45 clips consumed by sharp dissection. The 2 groups were not different regarding postoperative complications, except for 3 cases of temporary paresthesia of the thumb in the electrocautery group; histopathologic examination found no endothelial damage. We conclude that radial artery harvesting by electrocautery is faster and more economical than harvesting by sharp dissection and is associated with better intraoperative flow and good preservation of endothelial integrity. PMID:16572861
Rahman, Yuli Asmi; Manjang, Salama; Yusran, Ilham, Amil Ahmad
2018-03-01
Power loss minimization have many advantagess to the distribution system radial among others reduction of power flow in feeder lines, freeing stress on feeder loading, deterrence of power procurement from the grid and also the cost of loss compensating instruments. This paper, presents capacitor and photovoltaic (PV) placement as alternative means to decrease power system losses. The paper aims to evaluate the best alternative for decreasing power system losses and improving voltage profile in the radial distribution system. To achieve the objectives of paper, they are used three cases tested by Electric Transient and Analysis Program (ETAP) simulation. Firstly, it performs simulation of placement capacitor. Secondly, simulated placement of PV. Lastly, it runs simulation of placement capacitor and PV simultaneously. The simulations were validated using the IEEE 34-bus test system. As a result, they proved that the installation of capacitor and PV integration simultaneously leading to voltage profile correction and power losses minimization significantly.
Should School Nurses Wear Uniforms?
Journal of School Health, 2001
2001-01-01
This 1958 paper questions whether school nurses should wear uniforms (specifically, white uniforms). It concludes that white uniforms are often associated with the treatment of ill people, and since many people have a fear reaction to them, they are not necessary and are even undesirable. Since school nurses are school staff members, they should…
Radial distribution of ions in pores with a surface charge
Stegen, J.H.G. van der; Görtzen, J.; Kuipers, J.A.M.; Hogendoorn, J.A.; Versteeg, G.F.
2001-01-01
A sorption model applicable to calculate the radial equilibrium concentrations of ions in the pores of ion-selective membranes with a pore structure is developed. The model is called the radial uptake model. Because the model is applied to a Nafion sulfonic layer with very small pores and the radial
International Nuclear Information System (INIS)
Li Zhikang; Zhao Libo; Ye Zhiying; Zhao Yulong; Jiang Zhuangde; Wang Hongyan
2013-01-01
The resonant frequency of a microplate is influenced by various physical parameters such as mass, surface stress, hydrostatic pressure and electrostatic force. In this paper, the effects of both electrostatic force and uniform hydrostatic pressure on the resonant frequency of a clamped circular microplate are investigated. An approximate solution is derived for the fundamental resonance frequency of the mciroplate under both types of loads using an energy equivalent method. It is found that both electrostatic force and uniform hydrostatic pressure decrease the resonant frequency of the microplate under small deflections. Additionally, the linearized expression of this solution shows that the resonant frequency varies linearly with pressure in the low and ultra-low range, and the corresponding pressure sensitivity depends on the voltage applied to the microplate. The analytical results are well validated by the finite element method. This study may be helpful for the design and optimization of electrostatically actuated resonance devices based on microplates, especially electrostatically actuated low- or ultra-low-pressure sensors. (paper)
The Matlab Radial Basis Function Toolbox
Directory of Open Access Journals (Sweden)
Scott A. Sarra
2017-03-01
Full Text Available Radial Basis Function (RBF methods are important tools for scattered data interpolation and for the solution of Partial Differential Equations in complexly shaped domains. The most straight forward approach used to evaluate the methods involves solving a linear system which is typically poorly conditioned. The Matlab Radial Basis Function toolbox features a regularization method for the ill-conditioned system, extended precision floating point arithmetic, and symmetry exploitation for the purpose of reducing flop counts of the associated numerical linear algebra algorithms.
Stellar Angular Momentum Distributions and Preferential Radial Migration
Wyse, Rosemary; Daniel, Kathryne J.
2018-04-01
I will present some results from our recent investigations into the efficiency of radial migration in stellar disks of differing angular momentum distributions, within a given adopted 2D spiral disk potential. We apply to our models an analytic criterion that determines whether or not individual stars are in orbits that could lead to radial migration around the corotation resonance. We couch our results in terms of the local stellar velocity dispersion and find that the fraction of stars that could migrate radially decreases as the velocity dispersion increases. I will discuss implications and comparisons with the results of other approaches.
Research on Radial Vibration of a Circular Plate
Directory of Open Access Journals (Sweden)
Wei Liu
2016-01-01
Full Text Available Radial vibration of the circular plate is presented using wave propagation approach and classical method containing Bessel solution and Hankel solution for calculating the natural frequency theoretically. In cylindrical coordinate system, in order to obtain natural frequency, propagation and reflection matrices are deduced at the boundaries of free-free, fixed-fixed, and fixed-free using wave propagation approach. Furthermore, radial phononic crystal is constructed by connecting two materials periodically for the analysis of band phenomenon. Also, Finite Element Simulation (FEM is adopted to verify the theoretical results. Finally, the radial and piezoelectric effects on the band are also discussed.
Radial-probe EBUS for the diagnosis of peripheral pulmonary lesions.
Jacomelli, Marcia; Demarzo, Sergio Eduardo; Cardoso, Paulo Francisco Guerreiro; Palomino, Addy Lidvina Mejia; Figueiredo, Viviane Rossi
2016-01-01
Conventional bronchoscopy has a low diagnostic yield for peripheral pulmonary lesions. Radial-probe EBUS employs a rotating ultrasound transducer at the end of a probe that is passed through the working channel of the bronchoscope. Radial-probe EBUS facilitates the localization of peripheral pulmonary nodules, thus increasing the diagnostic yield. The objective of this study was to present our initial experience using radial-probe EBUS in the diagnosis of peripheral pulmonary lesions at a tertiary hospital. We conducted a retrospective analysis of 54 patients who underwent radial-probe EBUS-guided bronchoscopy for the investigation of pulmonary nodules or masses between February of 2012 and September of 2013. Radial-probe EBUS was performed with a flexible 20-MHz probe, which was passed through the working channel of the bronchoscope and advanced through the bronchus to the target lesion. For localization of the lesion and for collection procedures (bronchial brushing, transbronchial needle aspiration, and transbronchial biopsy), we used fluoroscopy. Radial-probe EBUS identified 39 nodules (mean diameter, 1.9 ± 0.7 cm) and 19 masses (mean diameter, 4.1 ± 0.9 cm). The overall sensitivity of the method was 66.7% (79.5% and 25.0%, respectively, for lesions that were visible and not visible by radial-probe EBUS). Among the lesions that were visible by radial-probe EBUS, the sensitivity was 91.7% for masses and 74.1% for nodules. The complications were pneumothorax (in 3.7%) and bronchial bleeding, which was controlled bronchoscopically (in 9.3%). Radial-probe EBUS shows a good safety profile, a low complication rate, and high sensitivity for the diagnosis of peripheral pulmonary lesions. A broncoscopia convencional possui baixo rendimento diagnóstico para lesões pulmonares periféricas. A ecobroncoscopia radial (EBUS radial) emprega um transdutor ultrassonográfico rotatório na extremidade de uma sonda que é inserida no canal de trabalho do broncoscópio. O EBUS
Radial vibration and ultrasonic field of a long tubular ultrasonic radiator.
Shuyu, Lin; Zhiqiang, Fu; Xiaoli, Zhang; Yong, Wang; Jing, Hu
2013-09-01
The radial vibration of a metal long circular tube is studied analytically and its electro-mechanical equivalent circuit is obtained. Based on the equivalent circuit, the radial resonance frequency equation is derived. The theoretical relationship between the radial resonance frequency and the geometrical dimensions is studied. Finite element method is used to simulate the radial vibration and the radiated ultrasonic field and the results are compared with those from the analytical method. It is concluded that the radial resonance frequency for a solid metal rod is larger than that for a metal tube with the same outer radius. The radial resonance frequencies from the analytical method are in good agreement with those from the numerical method. Based on the acoustic field analysis, it is concluded that the long metal tube with small wall thickness is superior to that with large wall thickness in producing radial vibration and ultrasonic radiation. Therefore, it is expected to be used as an effective radial ultrasonic radiator in ultrasonic sewage treatment, ultrasonic antiscale and descaling and other ultrasonic liquid handling applications. Copyright © 2013 Elsevier B.V. All rights reserved.
Stabe, R. G.; Whitney, W. J.; Moffitt, T. P.
1984-01-01
Experimental results are presented for a 0.767 scale model of the first stage of a two-stage turbine designed for a high by-pass ratio engine. The turbine was tested with both uniform inlet conditions and with an inlet radial temperature profile simulating engine conditions. The inlet temperature profile was essentially mixed-out in the rotor. There was also substantial underturning of the exit flow at the mean diameter. Both of these effects were attributed to strong secondary flows in the rotor blading. There were no significant differences in the stage performance with either inlet condition when differences in tip clearance were considered. Performance was very close to design intent in both cases. Previously announced in STAR as N84-24589
Assessment of Wind Parameter Sensitivity on Ultimate and Fatigue Wind Turbine Loads: Preprint
Energy Technology Data Exchange (ETDEWEB)
Robertson, Amy N [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Sethuraman, Latha [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Jonkman, Jason [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Quick, Julian [National Renewable Energy Laboratory (NREL), Golden, CO (United States)
2018-02-13
Wind turbines are designed using a set of simulations to ascertain the structural loads that the turbine could encounter. While mean hub-height wind speed is considered to vary, other wind parameters such as turbulence spectra, sheer, veer, spatial coherence, and component correlation are fixed or conditional values that, in reality, could have different characteristics at different sites and have a significant effect on the resulting loads. This paper therefore seeks to assess the sensitivity of different wind parameters on the resulting ultimate and fatigue loads on the turbine during normal operational conditions. Eighteen different wind parameters are screened using an Elementary Effects approach with radial points. As expected, the results show a high sensitivity of the loads to the turbulence standard deviation in the primary wind direction, but the sensitivity to wind shear is often much greater. To a lesser extent, other wind parameters that drive loads include the coherence in the primary wind direction and veer.
Czech Academy of Sciences Publication Activity Database
Coufal, David
2017-01-01
Roč. 319, 15 July (2017), s. 1-27 ISSN 0165-0114 R&D Projects: GA MŠk(CZ) LD13002 Institutional support: RVO:67985807 Keywords : fuzzy systems * radial functions * coherence Subject RIV: BA - General Mathematics OBOR OECD: Computer sciences, information science, bioinformathics (hardware development to be 2.2, social aspect to be 5.8) Impact factor: 2.718, year: 2016
Directory of Open Access Journals (Sweden)
Pedro Beraldo de Andrade
2011-04-01
Full Text Available FUNDAMENTO: Embora a técnica radial exiba resultados incontestáveis na redução de complicações vasculares e ocorrência de sangramento grave quando comparada à técnica femoral, seu emprego permanece restrito a poucos centros que a elegeram como via de acesso preferencial. OBJETIVO: Avaliar o cenário atual das intervenções coronarianas percutâneas no Brasil quanto à utilização da via de acesso radial. MÉTODOS: Análise dos dados cadastrados de forma espontânea na Central Nacional de Intervenções Cardiovasculares (CENIC durante o quadriênio de 2005-2008, o que totaliza 83.376 procedimentos. RESULTADOS: A técnica radial foi utilizada em 12,6% dos procedimentos efetivados, e a técnica femoral, em 84,3%. Os 3,1% restantes foram representados pela dissecção ou punção braquial. Com uma taxa de sucesso de 97,5%, a opção pelo acesso radial associou-se à redução significativa de complicações vasculares quando comparado ao femoral (2,5% versus 3,6%, p FUNDAMENTO: Aunque la técnica radial exhiba resultados incontestables en la reducción de complicaciones vasculares y ocurrencia de sangrado grave cuando es comparada a la técnica femoral, su empleo permanece restringido a pocos centros que la eligieron como vía de acceso preferencial. OBJETIVO:Evaluar el escenario actual de las intervenciones coronarias percutáneas en el Brasil en cuanto a la utilización de la vía de acceso radial. MÉTODOS:Análisis de los datos registrados de forma espontánea en la Central Nacional de Intervenciones Cardiovasculares (CENIC durante el cuatrienio de 2005-2008, lo que totaliza 83.376 procedimientos. RESULTADOS:La técnica radial fue utilizada en 12,6% de los procedimientos efectuados, y la técnica femoral, en 84,3%. Los 3,1% restantes fueron representados por la disección o punción braquial. Con una tasa de éxito de 97,5%, la opción por el acceso radial se asoció a la reducción significativa de complicaciones vasculares cuando
Velocidades radiales en Collinder 121
Arnal, M.; Morrell, N.
Se han llevado a cabo observaciones espectroscópicas de unas treinta estrellas que son posibles miembros del cúmulo abierto Collinder 121. Las mismas fueron realizadas con el telescopio de 2.15m del Complejo Astronómico El Leoncito (CASLEO). El análisis de las velocidades radiales derivadas del material obtenido, confirma la realidad de Collinder 121, al menos desde el punto de vista cinemático. La velocidad radial baricentral (LSR) del cúmulo es de +17 ± 3 km.s-1. Esta velocidad coincide, dentro de los errores, con la velocidad radial (LSR) de la nebulosa anillo S308, la cual es de ~20 ± 10 km.s-1. Como S308 se encuentra físicamente asociada a la estrella Wolf-Rayet HD~50896, es muy probable que esta última sea un miembro de Collinder 121. Desde un punto de vista cinemático, la supergigante roja HD~50877 (K3Iab) también pertenecería a Collinder 121. Basándonos en la pertenencia de HD~50896 a Collinder 121, y en la interacción encontrada entre el viento de esta estrella y el medio interestelar circundante a la misma, se estima para este cúmulo una distancia del orden de 1 kpc.
Core/corona modeling of diode-imploded annular loads
Terry, R. E.; Guillory, J. U.
1980-11-01
The effects of a tenuous exterior plasma corona with anomalous resistivity on the compression and heating of a hollow, collisional aluminum z-pinch plasma are predicted by a one-dimensional code. As the interior ("core") plasma is imploded by its axial current, the energy exchange between core and corona determines the current partition. Under the conditions of rapid core heating and compression, the increase in coronal current provides a trade-off between radial acceleration and compression, which reduces the implosion forces and softens the pitch. Combined with a heuristic account of energy and momentum transport in the strongly coupled core plasma and an approximate radiative loss calculation including Al line, recombination and Bremsstrahlung emission, the current model can provide a reasonably accurate description of imploding annular plasma loads that remain azimuthally symmetric. The implications for optimization of generator load coupling are examined.
Radial supports of face motors with slack compensation
Energy Technology Data Exchange (ETDEWEB)
Kuznetsova, I I; Gelman, A B; Krekina, T V
1982-01-01
The design of a radial support of a face motor with slack compensation is described, and gives the results of field tests which confirm the performance capacity of the experimental support both from the viewpoint of durability, and in relation to preventing radial slack of the face motor shaft.
Directory of Open Access Journals (Sweden)
José Edilberto Pacheco Serrano
2000-06-01
Full Text Available La miniqueratotomía radial se viene realizando desde 1995. Se plantea que incisiones más cortas tienen el mismo efecto y producen menos debilidad corneal, ya que disminuye la susceptibilidad a sufrir complicaciones graves provenientes de traumas de la vida cotidiana. Esta idea nos motivó a realizar un estudio para observar el comportamiento de incisiones más cortas en nuestro centro y, en caso de resultados positivos, implementar la técnica de manera que nuestros pacientes puedan beneficiarse de ella. Se comparan resultados de la aplicación de dos técnicas quirúrgicas refractivas para corrección de miopía entre leve y moderada. Se seleccionaron 38 pacientes entre 20 y 40 años de edad, con miopías entre -2 y -6 dioptrías y astigmatismo no mayor a -0,75 dioptrías. Se realizó queratotomía radial convencional en el ojo derecho y miniqueratotomía radial en el ojo izquierdo del mismo paciente. Las variaciones obtenidas en promedio fueron, en el ojo derecho: la esfera (en dioptrías D de -3,38 a -0,32, cilindro de -0,48 a -0,45 D, la queratometría de 44,75 a 41,21 D. En el ojo izquierdo: la esfera de -3,38 D a -0,44 D, cilindro de -0,44 D a -0,38 D, la queratometría de 44,83 a 41,80 D. Hubo una mejoría de la agudeza visual sin cristales de 0,61 en el ojo derecho y 0,59 en el ojo izquierdo. Las dos técnicas no mostraron diferencias estadísticamente significativas, con el beneficio de que la nueva técnica disminuye el riesgo de ruptura postraumática, según la bibliografía revisada, a causa de la menor injuria corneal.In this hospital, radial keratotomy is performed sice 1995. We propose that shorter incisions have some effect and cause less corneal weakness, since dicreases susceptibility to severe complications from traumata of daily life. This notion encouraged us to carry out a study to observe behaviour of shorter incisions in our service, and in the event of positive results, implementation of the technique so that our
Gagne, Nolan L; Cutright, Daniel R; Rivard, Mark J
2012-09-01
To improve tumor dose conformity and homogeneity for COMS plaque brachytherapy by investigating the dosimetric effects of varying component source ring radionuclides and source strengths. The MCNP5 Monte Carlo (MC) radiation transport code was used to simulate plaque heterogeneity-corrected dose distributions for individually-activated source rings of 14, 16 and 18 mm diameter COMS plaques, populated with (103)Pd, (125)I and (131)Cs sources. Ellipsoidal tumors were contoured for each plaque size and MATLAB programming was developed to generate tumor dose distributions for all possible ring weighting and radionuclide permutations for a given plaque size and source strength resolution, assuming a 75 Gy apical prescription dose. These dose distributions were analyzed for conformity and homogeneity and compared to reference dose distributions from uniformly-loaded (125)I plaques. The most conformal and homogeneous dose distributions were reproduced within a reference eye environment to assess organ-at-risk (OAR) doses in the Pinnacle(3) treatment planning system (TPS). The gamma-index analysis method was used to quantitatively compare MC and TPS-generated dose distributions. Concentrating > 97% of the total source strength in a single or pair of central (103)Pd seeds produced the most conformal dose distributions, with tumor basal doses a factor of 2-3 higher and OAR doses a factor of 2-3 lower than those of corresponding uniformly-loaded (125)I plaques. Concentrating 82-86% of the total source strength in peripherally-loaded (131)Cs seeds produced the most homogeneous dose distributions, with tumor basal doses 17-25% lower and OAR doses typically 20% higher than those of corresponding uniformly-loaded (125)I plaques. Gamma-index analysis found > 99% agreement between MC and TPS dose distributions. A method was developed to select intra-plaque ring radionuclide compositions and source strengths to deliver more conformal and homogeneous tumor dose distributions than
International Nuclear Information System (INIS)
Scherpelz, R.I.; MacLellan, J.A.
1987-09-01
The Pacific Northwest Laboratory (PNL) is sending a torso phantom with radioactive material uniformly distributed in the lungs to in vivo bioassay laboratories for analysis. Although the radionuclides ultimately chosen for the studies had relatively long half-lives, future accreditation testing will require repeated tests with short half-life test nuclides. Computer modeling was used to simulate the major components of the phantom. Radiation transport calculations were then performed using the computer models to calculate dose rates either 15 cm from the chest or at its surface. For 144 Ce and 60 Co, three configurations were used for the lung comparison tests. Calculations show that, for most detector positions, a single plug containing 40 K located in the back of the heart provides a good approximation to a uniform distribution of 40 K. The approximation would lead, however, to a positive bias for the detector reading if the detector were located at the chest surface near the center. Loading the 40 K in a uniform layer inside the chest wall is not a good approximation of the uniform distribution in the lungs, because most of the radionuclides would be situated close to the detector location and the only shielding would be the thickness of the chest wall. The calculated dose rates for 60 Co and 144 Ce were similar at all calculated reference points. 3 refs., 5 figs., 10 tabs
Pseudarthrosis of radial shaft with dislocation of heads of radial and ulnar bones (case report
Directory of Open Access Journals (Sweden)
M. E. Puseva
2013-01-01
Full Text Available The authors presented a rare clinical case - the injury of forearm complicated by the formation of the pseudarthrosis of the radial shaft in combination with old dislocation of heads the radius and ulna. The differentiated approach to the choice of surgical tactics was proposed, which consists of several consistent stages: taking free autotransplant from the crest of iliac bone, resection of pseudarthrosis of radius with replacement of the bone defect by the graft for restoration of anatomic length, conducting combined strained osteosynthesis and elimination of dislocation of a head of radial and ulnar bones by transosseous osteosynthesis. The chosen treatment strategy allowed to restore the anatomy and function of the upper extremity.
Numerical Simulation of the Ground Response to the Tire Load Using Finite Element Method
Valaskova, Veronika; Vlcek, Jozef
2017-10-01
Response of the pavement to the excitation caused by the moving vehicle is one of the actual problems of the civil engineering practice. The load from the vehicle is transferred to the pavement structure through contact area of the tires. Experimental studies show nonuniform distribution of the pressure in the area. This non-uniformity is caused by the flexible nature and the shape of the tire and is influenced by the tire inflation. Several tire load patterns, including uniform distribution and point load, were involved in the numerical modelling using finite element method. Applied tire loads were based on the tire contact forces of the lorry Tatra 815. There were selected two procedures for the calculations. The first one was based on the simplification of the vehicle to the half-part model. The characteristics of the vehicle model were verified by the experiment and by the numerical model in the software ADINA, when vehicle behaviour during the ride was investigated. Second step involved application of the calculated contact forces for the front axle as the load on the multi-layered half space representing the pavement structure. This procedure was realized in the software Plaxis and considered various stress patterns for the load. The response of the ground to the vehicle load was then analyzed. Axisymmetric model was established for this procedure. The paper presents the results of the investigation of the contact pressure distribution and corresponding reaction of the pavement to various load distribution patterns. The results show differences in some calculated quantities for different load patterns, which need to be verified by the experimental way when also ground response should be observed.
Devaney's chaos on uniform limit maps
International Nuclear Information System (INIS)
Yan Kesong; Zeng Fanping; Zhang Gengrong
2011-01-01
Highlights: → The transitivity may not been inherited even if the sequence functions mixing. → The sensitivity may not been inherited even if the iterates of sequence have some uniform convergence. → Some equivalence conditions for the transitivity and sensitivity for uniform limit function are given. → A non-transitive sequence may converge uniformly to a transitive map. - Abstract: Let (X, d) be a compact metric space and f n : X → X a sequence of continuous maps such that (f n ) converges uniformly to a map f. The purpose of this paper is to study the Devaney's chaos on the uniform limit f. On the one hand, we show that f is not necessarily transitive even if all f n mixing, and the sensitive dependence on initial conditions may not been inherited to f even if the iterates of the sequence have some uniform convergence, which correct two wrong claims in . On the other hand, we give some equivalence conditions for the uniform limit f to be transitive and to have sensitive dependence on initial conditions. Moreover, we present an example to show that a non-transitive sequence may converge uniformly to a transitive map.
Dependence of the trapping regions with the radial electric field in TJ-II
International Nuclear Information System (INIS)
Guasp, J.; Liniers, M.
1997-01-01
The influence of the electric field upon the radial and angular distributions of trapped ions of energies between 0.1 and 1 keV in TJ-II is analysed. Near the magnetic axis, with moderate electric fields, the trapped fraction increases for negative potentials and decreases for positive ones. Nevertheless for high potentials this decreasing for positive sign can be reversed. Near the plasma periphery trapping is affected only for high potentials and always increases, independently of the potential sign. The sensibility to negative potentials is always higher than for the positive ones. These trapping changes are almost uniform in poloidal and toroidal angular profiles and affect mainly to marginally trapped or passing particles. Nevertheless for high potentials or energie the resonances modify this behaviour and inhibit the increasing of trapping in the outer side or the torus. For the locally trapped population fraction a steady decrease with the potential appears independently of the sign, except very near the magnetic axis or the plasma periphery. The global result of all these partial effects is the presence of a wide trapping minimum for moderate positive electric potential, potential that increases with the ion energy as well as a strong increase for high electric fields of either sign, more visible for negative potentials and high energies. For the locally trapped population a steady decrease with potential appears independently of the sign. All these effects can be explained by the combined action of the appearance and elimination of radial magnetic barriers and of the electric field resonances. (Author)
Inductrack III configuration--a maglev system for high loads
Post, Richard F
2013-11-12
Inductrack III configurations are suited for use in transporting heavy freight loads. Inductrack III addresses a problem associated with the cantilevered track of the Inductrack II configuration. The use of a cantilevered track could present mechanical design problems in attempting to achieve a strong enough track system such that it would be capable of supporting very heavy loads. In Inductrack III, the levitating portion of the track can be supported uniformly from below, as the levitating Halbach array used on the moving vehicle is a single-sided one, thus does not require the cantilevered track as employed in Inductrack II.
Rf beam loading in the Brookhaven AGS with booster injection
International Nuclear Information System (INIS)
Zhang, S.Y.; Raka, E.; Weng, W.T.
1992-01-01
Multi-batch bunched beam loading during injection from the Booster to the AGS will be discussed. The full intensity beam injection to the upgraded AGS rf system with beam phase and radial feedbacks will be studied. It is shown that a beam phase feedback is necessary in order to guarantee a predictable hewn behavior after the first batch injection, otherwise the initial phase deviation for the following batch injections cannot be controlled. However, the effectiveness of the phase feedback control of the transient beam loading may be limited by an emittance blow up in the process. It is shown that a fast power amplifier feedback with a moderate gain can significantly reduce the transient effect of the bunched beam injection
Manufacturing of Precision Forgings by Radial Forging
International Nuclear Information System (INIS)
Wallner, S.; Harrer, O.; Buchmayr, B.; Hofer, F.
2011-01-01
Radial forging is a multi purpose incremental forging process using four tools on the same plane. It is widely used for the forming of tool steels, super alloys as well as titanium- and refractory metals. The range of application goes from reducing the diameters of shafts, tubes, stepped shafts and axels, as well as for creating internal profiles for tubes in Near-Net-Shape and Net-Shape quality. Based on actual development of a weight optimized transmission input shaft, the specific features of radial forging technology is demonstrated. Also a Finite Element Model for the simulation of the process is shown which leads to reduced pre-processing effort and reduced computing time compared to other published simulation methods for radial forging. The finite element model can be applied to quantify the effects of different forging strategies.
Radially truncated galactic discs
Grijs, R. de; Kregel, M.; Wesson, K H
2000-01-01
Abstract: We present the first results of a systematic analysis of radially truncatedexponential discs for four galaxies of a sample of disc-dominated edge-onspiral galaxies. Edge-on galaxies are very useful for the study of truncatedgalactic discs, since we can follow their light distributions out
Effects of drive current rise-time and initial load density distribution on Z-pinch characteristics
Institute of Scientific and Technical Information of China (English)
Duan Yao-Yong; Guo Yong-Hui; Wang Wen-Sheng; Qiu Ai-Ci
2005-01-01
A two-dimensional, three-temperature radiation magneto-hydrodynamics model is applied to the investigation of evolutional trends in x-ray radiation power, energy, peak plasma temperature and density as functions of drive current rise-time and initial load density distribution by using the typical experimental parameters of tungsten wire-array Z-pinch on the Qiangguang-Ⅰ generator. The numerical results show that as the drive current rise-time is shortened, x-ray radiation peak power, energy, peak plasma density and peak ion temperature increase approximately linearly, but among them the x-ray radiation peak power increases more quickly. As the initial plasma density distribution in the radial direction becomes gradually flattened, the peak radiation power and the peak ion-temperature almost exponentially increase, while the radiation energy and the peak plasma density change only a little. The main effect of shortening drive current rise-time is to enhance compression of plasma, and the effect of flattening initial load density distribution in the radial direction is to raise the plasma temperature. Both of the approaches elevate the x-ray peak radiation power.
Simulation of a 5MW wind turbine in an atmospheric boundary layer
International Nuclear Information System (INIS)
Meister, Konrad; Lutz, Thorsten; Krämer, Ewald
2014-01-01
This article presents detached eddy simulation (DES) results of a 5MW wind turbine in an unsteady atmospheric boundary layer. The evaluation performed in this article focuses on turbine blade loads as well as on the influence of atmospheric turbulence and tower on blade loads. Therefore, the turbulence transport of the atmospheric boundary layer to the turbine position is analyzed. To determine the influence of atmospheric turbulence on wind turbines the blade load spectrum is evaluated and compared to wind turbine simulation results with uniform inflow. Moreover, the influences of different frequency regimes and the tower on the blade loads are discussed. Finally, the normal force coefficient spectrum is analyzed at three different radial positions and the influence of tower and atmospheric turbulence is shown
Radial velocity observations of VB10
Deshpande, R.; Martin, E.; Zapatero Osorio, M. R.; Del Burgo, C.; Rodler, F.; Montgomery, M. M.
2011-07-01
VB 10 is the smallest star known to harbor a planet according to the recent astrometric study of Pravdo & Shaklan [1]. Here we present near-infrared (J-band) radial velocity of VB 10 performed from high resolution (R~20,000) spectroscopy (NIRSPEC/KECK II). Our results [2] suggest radial velocity variability with amplitude of ~1 km/s, a result that is consistent with the presence of a massive planet companion around VB10 as found via long-term astrometric monitoring of the star by Pravdo & Shaklan. Employing an entirely different technique we verify the results of Pravdo & Shaklan.
Zhang, Dong-ming; Yang, Yu-shun; Chu, Ya-pei; Zhang, Xiang; Xue, Yan-guang
2018-06-01
The triaxial compression test of crystalline sandstone under different loading and unloading velocity of confining pressure is carried out by using the self-made "THM coupled with servo-controlled seepage apparatus for containing-gas coal", analyzed the strength, deformation and permeability characteristics of the sample, the results show that: with the increase of confining pressures loading-unloading velocity, Mohr's stress circle center of the specimen shift to the right, and the ultimate intensity, peak strain and residual stress of the specimens increase gradually. With the decrease of unloading velocity of confining pressure, the axial strain, the radial strain and the volumetric strain of the sample decrease first and then increases, but the radial strain decreases more greatly. The loading and unloading of confining pressure has greater influence on axial strain of specimens. The deformation modulus decreases rapidly with the increase of axial strain and the Poisson's ratio decreases gradually at the initial stage of loading. When the confining pressure is loaded, the deformation modulus decrease gradually, and the Poisson's ratio increases gradually. When the confining pressure is unloaded, the deformation modulus increase gradually, and the Poisson's ratio decreases gradually. When the specimen reaches the ultimate intensity, the deformation modulus decreases rapidly, while the Poisson's ratio increases rapidly. The fitting curve of the confining pressure and the deformation modulus and the Poisson's ratio in accordance with the distribution of quadratic polynomial function in the loading-unloading confining pressure. There is a corresponding relationship between the evolution of rock permeability and damage deformation during the process of loading and unloading. In the late stage of yielding, the permeability increases slowly, and the permeability increases sharply after the rock sample is destroyed. Fitting the permeability and confining pressure
Experimental study on the CHF in uniformly and non-uniformly heated vertical annuli
Energy Technology Data Exchange (ETDEWEB)
Chun, Se Young; Moon, Sang Ki; Chung, Heung June; Park, Jong Kuk; Kim, Bok Deuk; Youn, Young Jung; Chung, Moon Ki
2001-09-01
Up to now, KAERI has performed critical heat flux experiments in water under zero-flow and low-flow conditions using a RCS CHF loop facility with uniformly and non-uniformly heated vertical annulus. Since the existing CHF experiments were mainly performed under low-pressure conditions, we performed the CHF experiment to investigate the pressure effect on the CHF under zero-flow and low-flow conditions for a wide range of system pressures. Also, two vertical annuli with the same geometry have been used to investigate the axial heat flux distributions on the CHF. This report summarizes the experimental results and provides the CHF data that can be used for the development for CHF correlation and a thermal hydraulic analysis code. The CHF data have been collected for system pressures ranging from 0.57 to 15.15 MPa, mass flux 0 and from 200 to 650 kg/m2s, inlet subcooling from 75 to 360 kJ/kg and exit quality from 0.07 to 0.57. At low-flow conditions, the total number of data are 242 and 290 with uniformly heated- and non-uniformly heated test sections, respectively. 41 and 94 CHF data are generated with uniformly heated- and non-uniformly heated test sections, respectively, in zero-flow CHF experiments that are performed by blocking test section bottoms. The CHF experiment result shows that the effects of system pressure, mass flux and inlet subcooling are consistent with conventional understandings and similar to those for round tubes. The behavior of the CHF is relatively complex at low pressures. Also, the effects of axial heat flux profile are large at low-pressure conditions.
Experimental study on the CHF in uniformly and non-uniformly heated vertical annuli
International Nuclear Information System (INIS)
Chun, Se Young; Moon, Sang Ki; Chung, Heung June; Park, Jong Kuk; Kim, Bok Deuk; Youn, Young Jung; Chung, Moon Ki
2001-09-01
Up to now, KAERI has performed critical heat flux experiments in water under zero-flow and low-flow conditions using a RCS CHF loop facility with uniformly and non-uniformly heated vertical annulus. Since the existing CHF experiments were mainly performed under low-pressure conditions, we performed the CHF experiment to investigate the pressure effect on the CHF under zero-flow and low-flow conditions for a wide range of system pressures. Also, two vertical annuli with the same geometry have been used to investigate the axial heat flux distributions on the CHF. This report summarizes the experimental results and provides the CHF data that can be used for the development for CHF correlation and a thermal hydraulic analysis code. The CHF data have been collected for system pressures ranging from 0.57 to 15.15 MPa, mass flux 0 and from 200 to 650 kg/m2s, inlet subcooling from 75 to 360 kJ/kg and exit quality from 0.07 to 0.57. At low-flow conditions, the total number of data are 242 and 290 with uniformly heated- and non-uniformly heated test sections, respectively. 41 and 94 CHF data are generated with uniformly heated- and non-uniformly heated test sections, respectively, in zero-flow CHF experiments that are performed by blocking test section bottoms. The CHF experiment result shows that the effects of system pressure, mass flux and inlet subcooling are consistent with conventional understandings and similar to those for round tubes. The behavior of the CHF is relatively complex at low pressures. Also, the effects of axial heat flux profile are large at low-pressure conditions
Radial scar/complex sclerosing lesion of the breast--value of ultrasound.
Grunwald, S; Heyer, H; Kühl, A; Schwesinger, G; Schimming, A; Köhler, G; Ohlinger, R
2007-04-01
Although benign, radial scar/complex sclerosing adenosis is a lesion which histopathologically resembles tubular carcinoma. On physical examination, it is difficult to distinguish radial scar from a malignant tumour. Mammography cannot differentiate radial scar from malignancy. This clinical study aims to delineate the role of preoperative ultrasonography with emphasis on the question whether ultrasonography could lower the number of false-positive readings and therefore the number of open biopsies required. In this examination, we present the clinical, mammographic, ultrasonographic, and histopathological features of 6 cases of radial scars. Although most authors describe radial scars as non-palpable, 2 of 6 lesions were indeed palpable. On mammograms, radial scars have a spiculated appearance, a feature observed in all of our cases. Numerous ultrasonographic characteristics are listed in the literature, but ultrasonography is not reported to have clear-cut advantages. Although this study did not elucidate any unique ultrasonographic features to characterise these lesions, the analysis of all ultrasonographic results made us recognise a set of "nearly specific ultrasonographic features" of radial scars. Current B-mode imaging does not appear to lead to the desirable reduction of the rate of unnecessary open biopsies.
Radial Structure Scaffolds Convolution Patterns of Developing Cerebral Cortex
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Mir Jalil Razavi
2017-08-01
Full Text Available Commonly-preserved radial convolution is a prominent characteristic of the mammalian cerebral cortex. Endeavors from multiple disciplines have been devoted for decades to explore the causes for this enigmatic structure. However, the underlying mechanisms that lead to consistent cortical convolution patterns still remain poorly understood. In this work, inspired by prior studies, we propose and evaluate a plausible theory that radial convolution during the early development of the brain is sculptured by radial structures consisting of radial glial cells (RGCs and maturing axons. Specifically, the regionally heterogeneous development and distribution of RGCs controlled by Trnp1 regulate the convex and concave convolution patterns (gyri and sulci in the radial direction, while the interplay of RGCs' effects on convolution and axons regulates the convex (gyral convolution patterns. This theory is assessed by observations and measurements in literature from multiple disciplines such as neurobiology, genetics, biomechanics, etc., at multiple scales to date. Particularly, this theory is further validated by multimodal imaging data analysis and computational simulations in this study. We offer a versatile and descriptive study model that can provide reasonable explanations of observations, experiments, and simulations of the characteristic mammalian cortical folding.
School Uniforms. Research Brief
Walker, Karen
2007-01-01
Does clothing make the person or does the person make the clothing? How does what attire a student wears to school affect their academic achievement? In 1996, President Clinton cited examples of school violence and discipline issues that might have been avoided had the students been wearing uniforms ("School uniforms: Prevention or suppression?").…
Beni, Yaghoub Tadi; Zeverdejani, M Karimi; Mehralian, Fahimeh
2017-10-01
Protein microtubules (MTs) are one of the important intercellular components and have a vital role in the stability and strength of the cells. Due to applied external loads, protein microtubules may be involved buckling phenomenon. Due to impact of protein microtubules in cell reactions, it is important to determine their critical buckling load. Considering nature of protein microtubules, various parameters are effective on microtubules buckling. The small size of microtubules and also lack of uniformity of MTs properties in different directions caused the necessity of accuracy in the analysis of these bio-structure. In fact, microtubules must be considered as a size dependent cylinder, which behave as an orthotropic material. Hence, in the present work using first-order shear deformation model (FSDT), the buckling equations of anisotropic MTs are derived based on new modified couple stress theory (NMCST). After solving the stability equations, the influences of various parameters are measured on the MTs critical buckling load. Copyright © 2017 Elsevier Inc. All rights reserved.
Davis, Pamela A.; Lopez, Mercedes C.
1988-01-01
An investigation was conducted to determine the static mechanical properties of a 30 x 11.5 to 14.5, Type 8, bias-ply and radial-belted aircraft tire. The properties measured were the spring rate and damping characteristics of each tire from vertical- and lateral-loading hysteresis loops. Mass moment of inertia tests were also conducted. The results of the study are presented along with a discussion of the advantages and disadvantages of each type of tire.
International Nuclear Information System (INIS)
De, P.K.; John, J.T.; Raman, V.V.; Banerjee, S.
1991-01-01
Zr-2.5Nb-0.5Cu garter springs which are placed between coolant and calandria tubes in PHWRs experience complex loading due to simultaneous application of tension, compression and torus bending moment due to coolant tubes. The gradual pick up of hydrogen by the garter springs during service is likely to have hydride platelets reoriented under the applied stresses. In the present paper, the magnitudes and the directions of the principal stresses under the complex loading condition obtained have been calculated and the extent of hydride reorientation predicted. Simulation experiments consisting of simulated loading of hydrogen (upto 400 ppm) precharged springs at the service temperature (300degC) and also in-situ hydrogen charging of the springs under simulated loading conditions have been carried out. In addition, hydrogen precharged springs have been subjected to temperature cycling between 50 and 300degC under complex loading conditions, to evaluate the influence of temperature variation on hydride reorientation. Metallographic examination of the hydride platelets in the above springs has shown an excellent agreement with the analytical prediction. Torus bending moment values appear to play a significant role in reorienting the hydride platelets. It has been observed that under normal torus bending moment corresponding to 90 mm dia coolant tubes hydrogen platelets close to the outer rim of the spiral get reoriented in the radial direction. However, on application a torus bending moment corresponding to 30 mm dia tubes, hydride platelets get reoriented along the radial direction, irrespective of the magnitude of tensile and compression loading. (author). 9 refs., 15 figs., 1 appendix
Energy Technology Data Exchange (ETDEWEB)
Pintsuk, G., E-mail: g.pintsuk@fz-juelich.de [Forschungszentrum Jülich GmbH, Euratom Association, D-52425 Jülich (Germany); Bobin-Vastra, I.; Constans, S. [AREVA NP PTCMI-F, Centre Technique, Fusion, F-71200 Le Creusot (France); Gavila, P. [Fusion for Energy, E-08019 Barcelona (Spain); Rödig, M. [Forschungszentrum Jülich GmbH, Euratom Association, D-52425 Jülich (Germany); Riccardi, B. [Fusion for Energy, E-08019 Barcelona (Spain)
2013-10-15
Highlights: • We characterize tungsten mono-block components after exposure to ITER relevant heat loads. • We qualify the manufacturing technology, i.e., hot isostatic pressing and hot radial pressing, and repair technologies. • We determine the microstructural influences, i.e., rod vs. plate material, on the damage evolution. • Needle like microstructures increase the risk of deep crack formation due to a limited fracture strength. -- Abstract: In order to evaluate the option to start the ITER operation with a full tungsten (W) divertor, high heat flux tests were performed in the electron beam facility FE200, Le Creusot, France. Thereby, in total eight small-scale and three medium-scale monoblock mock-ups produced with different manufacturing technologies and different tungsten grades were exposed to cyclic steady state heat loads. The applied power density ranges from 10 to 20 MW/m{sup 2} with a maximum of 1000 cycles at each particular loading step. Finally, on a reduced number of tiles, critical heat flux tests in the range of 30 MW/m{sup 2} were performed. Besides macroscopic and microscopic images of the loaded surface areas, detailed metallographic analyses were performed in order to characterize the occurring damages, i.e., crack formation, recrystallization, and melting. Thereby, the different joining technologies, i.e., hot radial pressing (HRP) vs. hot isostatic pressing (HIP) of tungsten to the Cu-based cooling tube, were qualified showing a higher stability and reproducibility of the HIP technology also as repair technology. Finally, the material response at the loaded top surface was found to be depending on the material grade, microstructural orientation, and recrystallization state of the material. These damages might be triggered by the application of thermal shock loads during electron beam surface scanning and not by the steady state heat load only. However, the superposition of thermal fatigue loads and thermal shocks as also expected
Hope, Sarah A; Meredith, Ian T; Tay, David; Cameron, James D
2007-09-01
Arterial transfer functions (TFs) describe the relationship between the pressure waveform at different arterial sites. Generalized TFs are used to reconstruct central aortic waveforms from non-invasively obtained peripheral waveforms and have been promoted as potentially clinically useful. A limitation is the paucity of information on their 'generalizability' with no information existing on the number of subjects required to construct a satisfactory TF, nor is adequate prospective validation available. We therefore investigated the uniformity of radial-aortic TFs and prospectively estimated the capacity of a generalized TF to reconstruct individual central blood pressure parameters. Ninety-three subjects (64 male) were studied by simultaneous radial applanation and high-fidelity (Millar Mikro-tip catheter) direct measurement of central aortic BP during elective coronary procedures. Subjects were prospectively randomized to either a derivation or validation group. Increasing numbers of individual TFs from the derivation group were averaged to form a generalized TF. There was minimal change with greater than 20 TFs averaged. In the validation group, the error in most reconstructed parameters related to the absolute value of the directly measured parameter [systolic blood pressure (SBP) and pulse pressure, Pcentral aortic SBP and pulse pressure (negatively) and time to peak systole (positively) (all PInclusion of more than 20 individual TFs in the construction of a generalized TF does not improve 'generalizability'. There appear to be systematic errors in derived central pressure waveforms and derived aortic augmentation index is inaccurate compared to the directly measured value.
Interfacial characteristics of hybrid nanocomposite under thermomechanical loading
Choyal, Vijay; Kundalwal, Shailesh I.
2017-12-01
In this work, an improved shear lag model was developed to investigate the interfacial characteristics of three-phase hybrid nanocomposite which is reinforced with microscale fibers augmented with carbon nanotubes on their circumferential surfaces. The shear lag model accounts for (i) radial and axial deformations of different transversely isotropic constituents, (ii) thermomechanical loads on the representative volume element (RVE), and (iii) staggering effect of adjacent RVEs. The results from the current newly developed shear lag model are validated with the finite element simulations and found to be in good agreement. This study reveals that the reduction in the maximum value of the axial stress in the fiber and the interfacial shear stress along its length become more pronounced in the presence of applied thermomechanical loads on the staggered RVEs. The existence of shear tractions along the RVE length plays a significant role in the interfacial characteristics and cannot be ignored.
Helicon modes in uniform plasmas. III. Angular momentum
International Nuclear Information System (INIS)
Stenzel, R. L.; Urrutia, J. M.
2015-01-01
Helicons are electromagnetic waves with helical phase fronts propagating in the whistler mode in magnetized plasmas and solids. They have similar properties to electromagnetic waves with angular momentum in free space. Helicons are circularly polarized waves carrying spin angular momentum and orbital angular momentum due to their propagation around the ambient magnetic field B 0 . These properties have not been considered in the community of researchers working on helicon plasma sources, but are the topic of the present work. The present work focuses on the field topology of helicons in unbounded plasmas, not on helicon source physics. Helicons are excited in a large uniform laboratory plasma with a magnetic loop antenna whose dipole axis is aligned along or across B 0 . The wave fields are measured in orthogonal planes and extended to three dimensions (3D) by interpolation. Since density and B 0 are uniform, small amplitude waves from loops at different locations can be superimposed to generate complex antenna patterns. With a circular array of phase shifted loops, whistler modes with angular and axial wave propagation, i.e., helicons, are generated. Without boundaries radial propagation also arises. The azimuthal mode number m can be positive or negative while the field polarization remains right-hand circular. The conservation of energy and momentum implies that these field quantities are transferred to matter which causes damping or reflection. Wave-particle interactions with fast electrons are possible by Doppler shifted resonances. The transverse Doppler shift is demonstrated. Wave-wave interactions are also shown by showing collisions between different helicons. Whistler turbulence does not always have to be created by nonlinear wave-interactions but can also be a linear superposition of waves from random sources. In helicon collisions, the linear and/or orbital angular momenta can be canceled, which results in a great variety of field topologies. The work
The mathematical description of uniformity and related theorems
International Nuclear Information System (INIS)
Luo Chuanwen; Yi Chundi; Wang Gang; Li Longsuo; Wang Chuncheng
2009-01-01
Uniform index is a conception that can describe the uniformity of a finite point set in a polyhedron, and is closely related to chaos. In order to study uniform index, the concept of contained uniform index is defined, which is similar to uniform index and has good mathematical properties. In this paper, we prove the convergence of the contained uniform index, and develop the base of proving the convergence of uniform index.
Fuel radial design using Path Relinking
International Nuclear Information System (INIS)
Campos S, Y.
2007-01-01
The present work shows the obtained results when implementing the combinatory optimization technique well-known as Path Re linking (Re-linkage of Trajectories), to the problem of the radial design of nuclear fuel assemblies, for boiling water reactors (BWR Boiling Water Reactor by its initials in English), this type of reactors is those that are used in the Laguna Verde Nucleo electric Central, Veracruz. As in any other electric power generation plant of that make use of some fuel to produce heat and that it needs each certain time (from 12 to 14 months) to make a supply of the same one, because this it wears away or it burns, in the nucleolectric plants to this activity is denominated fuel reload. In this reload different activities intervene, among those which its highlight the radial and axial designs of fuel assemblies, the patterns of control rods and the multi cycles study, each one of these stages with their own complexity. This work was limited to study in independent form the radial design, without considering the other activities. These phases are basic for the fuel reload design and of reactor operation strategies. (Author)
Numerical Simulation of Hydraulic Fracture Propagation Guided by Single Radial Boreholes
Directory of Open Access Journals (Sweden)
Tiankui Guo
2017-10-01
Full Text Available Conventional hydraulic fracturing is not effective in target oil development zones with available wellbores located in the azimuth of the non-maximum horizontal in-situ stress. To some extent, we think that the radial hydraulic jet drilling has the function of guiding hydraulic fracture propagation direction and promoting deep penetration, but this notion currently lacks an effective theoretical support for fracture propagation. In order to verify the technology, a 3D extended finite element numerical model of hydraulic fracturing promoted by the single radial borehole was established, and the influences of nine factors on propagation of hydraulic fracture guided by the single radial borehole were comprehensively analyzed. Moreover, the term ‘Guidance factor (Gf’ was introduced for the first time to effectively quantify the radial borehole guidance. The guidance of nine factors was evaluated through gray correlation analysis. The experimental results were consistent with the numerical simulation results to a certain extent. The study provides theoretical evidence for the artificial control technology of directional propagation of hydraulic fracture promoted by the single radial borehole, and it predicts the guidance effect of a single radial borehole on hydraulic fracture to a certain extent, which is helpful for planning well-completion and fracturing operation parameters in radial borehole-promoted hydraulic fracturing technology.
Radial collective flow in heavy-ion collisions at intermediate energies
International Nuclear Information System (INIS)
Borderie, B.
1996-11-01
The production of radial collective flow is associated with collisions leading to sources which undergo multifragmentation/explosion processes. After a theoretical survey of possible causes of production of radial flow, methods used to derive experimental values are discussed. Finally, a large set of data is presented which can be used to study and disentangle the different effects leading to radial collective flow. The dominant role of compression in the lower energy domain is emphasized. (author)
Engineering to Control Noise, Loading, and Optimal Operating Points
International Nuclear Information System (INIS)
Mitchell R. Swartz
2000-01-01
Successful engineering of low-energy nuclear systems requires control of noise, loading, and optimum operating point (OOP) manifolds. The latter result from the biphasic system response of low-energy nuclear reaction (LENR)/cold fusion systems, and their ash production rate, to input electrical power. Knowledge of the optimal operating point manifold can improve the reproducibility and efficacy of these systems in several ways. Improved control of noise, loading, and peak production rates is available through the study, and use, of OOP manifolds. Engineering of systems toward the OOP-manifold drive-point peak may, with inclusion of geometric factors, permit more accurate uniform determinations of the calibrated activity of these materials/systems
Crumb Rubber-Concrete Panels Under Blast Loads
2010-05-01
and the samples were labeled. Samples were picked up with an overhead crane and a form spreader connected to two points on the sample, each outside...uniform loading. Shortly after test started 8 to 9 cracks developed within quarter points and 2 cracks developed through pick points where form spreader ...dynamic behaviour of recycled tyre rubber-filled concrete.” Cem. Concr. Res., 32, 1587–1596. Huang, B., Li, G., Pang, S. S., and Eggers, J. (2004
Excitation and analytical characteristics of an ethanol loaded U-shaped arc
Directory of Open Access Journals (Sweden)
MIRJANA TRIPKOVIC
2003-02-01
Full Text Available The effect of the ethanol load on the discharge and analytical parameters of an argon stabilised U-shaped DC arc has been recorded. Measurements of the radial distribution of the apparent temperatures and the electron number density of the DC plasma showed that ethanol addition causes a decrease in both plasma parameters. The changes in the plasma characteristics, as well as in transport and atomisation processes of the analyte cause a general change in the spectral line intensities, which depends on the physical characteristics of the analyte and the quantity of ethanol loaded into the plasma. Improved detection limits were obtained for V and Mn when a 10 % (v/v waterethanol solution was nebulized into the plasma.
Fast radial basis functions for engineering applications
Biancolini, Marco Evangelos
2017-01-01
This book presents the first “How To” guide to the use of radial basis functions (RBF). It provides a clear vision of their potential, an overview of ready-for-use computational tools and precise guidelines to implement new engineering applications of RBF. Radial basis functions (RBF) are a mathematical tool mature enough for useful engineering applications. Their mathematical foundation is well established and the tool has proven to be effective in many fields, as the mathematical framework can be adapted in several ways. A candidate application can be faced considering the features of RBF: multidimensional space (including 2D and 3D), numerous radial functions available, global and compact support, interpolation/regression. This great flexibility makes RBF attractive – and their great potential has only been partially discovered. This is because of the difficulty in taking a first step toward RBF as they are not commonly part of engineers’ cultural background, but also due to the numerical complex...
Uniform irradiation using rotational-linear scanning method for narrow synchrotron radiation beam
International Nuclear Information System (INIS)
Nariyama, N.; Ohnishi, S.; Odano, N.
2004-01-01
At SPring-8, photon intensity monitors for synchrotron radiation have been developed. Using these monitors, the responses of radiation detectors and dosimeters to monoenergetic photons can be measured. In most cases, uniform irradiation to the sample is necessary. Here, two scanning methods are proposed. One is an XZ-linear scanning method, which moves the sample simultaneously in both the X and Z direction, that is, in zigzag fashion. The other is a rotational-linear scanning method, which rotates the sample moving in the X direction. To investigate the validity of the two methods, thermoluminescent dosimeters were irradiated with a broad synchrotron-radiation beam, and the readings from the two methods were compared with that of the dosimeters fixed in the beam. The results for both scanning methods virtually agreed with that of the fixed method. The advantages of the rotational-linear scanning method are that low- and medium-dose irradiation is possible, uniformity is excellent and the load to the scanning equipment is light: hence, this method is superior to the XZ-linear scanning method for most applications. (author)
Fields of an ultrashort tightly focused radially polarized laser pulse in a linear response plasma
Salamin, Yousef I.
2017-10-01
Analytical expressions for the fields of a radially polarized, ultrashort, and tightly focused laser pulse propagating in a linear-response plasma are derived and discussed. The fields are obtained from solving the inhomogeneous wave equations for the vector and scalar potentials, linked by the Lorenz gauge, in a plasma background. First, the scalar potential is eliminated using the gauge condition, then the vector potential is synthesized from Fourier components of an initial uniform distribution of wavenumbers, and the inverse Fourier transformation is carried out term-by-term in a truncated series (finite sum). The zeroth-order term in, for example, the axial electric field component is shown to model a pulse much better than its widely used paraxial approximation counterpart. Some of the propagation characteristics of the fields are discussed and all fields are shown to have manifested the expected limits for propagation in a vacuum.
On improved confinement in mirror plasmas by a radial electric field
Ågren, O.; Moiseenko, V. E.
2017-11-01
A weak radial electric field can suppress radial excursions of a guiding center from its mean magnetic surface. The physical origin of this effect is the smearing action by a poloidal E × B rotation, which tend to cancel out the inward and outward radial drifts. A use of this phenomenon may provide larger margins for magnetic field shaping with radial confinement of particles maintained in the collision free idealization. Mirror fields, stabilized by a quadrupolar field component, are of particular interest for their MHD stability and the possibility to control the quasi neutral radial electric field by biased potential plates outside the confinement region. Flux surface footprints on the end tank wall have to be traced to avoid short-circuiting between biased plates. Assuming a robust biasing procedure, moderate voltage demands for the biased plates seems adequate to cure even the radial excursions of Yushmanov ions which could be locally trapped near the mirrors. Analytical expressions are obtained for a magnetic quadrupolar mirror configuration which possesses minimal radial magnetic drifts in the central confinement region. By adding a weak controlled radial quasi-neutral electric field, the majority of gyro centers are predicted to be forced to move even closer to their respective mean magnetic surface. The gyro center radial coordinate is in such a case an accurate approximation for a constant of motion. By using this constant of motion, the analysis is in a Vlasov description extended to finite β. A correspondence between that Vlasov system and a fluid description with a scalar pressure and an electric potential is verified. The minimum B criterion is considered and implications for flute mode stability in the considered magnetic field is analyzed. By carrying out a long-thin expansion to a higher order, the validity of the calculations are extended to shorter and more compact device designs.
Probability distribution of distance in a uniform ellipsoid: Theory and applications to physics
International Nuclear Information System (INIS)
Parry, Michelle; Fischbach, Ephraim
2000-01-01
A number of authors have previously found the probability P n (r) that two points uniformly distributed in an n-dimensional sphere are separated by a distance r. This result greatly facilitates the calculation of self-energies of spherically symmetric matter distributions interacting by means of an arbitrary radially symmetric two-body potential. We present here the analogous results for P 2 (r;ε) and P 3 (r;ε) which respectively describe an ellipse and an ellipsoid whose major and minor axes are 2a and 2b. It is shown that for ε=(1-b 2 /a 2 ) 1/2 ≤1, P 2 (r;ε) and P 3 (r;ε) can be obtained as an expansion in powers of ε, and our results are valid through order ε 4 . As an application of these results we calculate the Coulomb energy of an ellipsoidal nucleus, and compare our result to an earlier result quoted in the literature. (c) 2000 American Institute of Physics
Radial Transport and Meridional Circulation in Accretion Disks
Energy Technology Data Exchange (ETDEWEB)
Philippov, Alexander A. [Department of Astrophysical Sciences, Princeton University, Ivy Lane, Princeton, NJ 08540 (United States); Rafikov, Roman R., E-mail: sashaph@princeton.edu [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States)
2017-03-10
Radial transport of particles, elements and fluid driven by internal stresses in three-dimensional (3D) astrophysical accretion disks is an important phenomenon, potentially relevant for the outward dust transport in protoplanetary disks, origin of the refractory particles in comets, isotopic equilibration in the Earth–Moon system, etc. To gain better insight into these processes, we explore the dependence of meridional circulation in 3D disks with shear viscosity on their thermal stratification, and demonstrate a strong effect of the latter on the radial flow. Previous locally isothermal studies have normally found a pattern of the radial outflow near the midplane, switching to inflow higher up. Here we show, both analytically and numerically, that a flow that is inward at all altitudes is possible in disks with entropy and temperature steeply increasing with height. Such thermodynamic conditions may be typical in the optically thin, viscously heated accretion disks. Disks in which these conditions do not hold should feature radial outflow near the midplane, as long as their internal stress is provided by the shear viscosity. Our results can also be used for designing hydrodynamical disk simulations with a prescribed pattern of the meridional circulation.
Detonation in supersonic radial outflow
Kasimov, Aslan R.; Korneev, Svyatoslav
2014-01-01
We report on the structure and dynamics of gaseous detonation stabilized in a supersonic flow emanating radially from a central source. The steady-state solutions are computed and their range of existence is investigated. Two-dimensional simulations
Uniform Statistical Convergence on Time Scales
Directory of Open Access Journals (Sweden)
Yavuz Altin
2014-01-01
Full Text Available We will introduce the concept of m- and (λ,m-uniform density of a set and m- and (λ,m-uniform statistical convergence on an arbitrary time scale. However, we will define m-uniform Cauchy function on a time scale. Furthermore, some relations about these new notions are also obtained.
International Nuclear Information System (INIS)
Gvildys, J.
1985-01-01
A sensitivity study of the HCDA slug impact response of fast reactor primary containment to properties of core surrounding structures was performed. Parameters such as the strength of the radial shield material, mass, void, and compressibility properties of the gas plenum material, mass of core material, and mass and compressibility properties of the coolant were used as variables to determine the magnitude of the slug impact loads. The response of the reactor primary containment and the partition of energy were also given. A study was also performed using water as coolant to study the difference in slug impact loads
International Nuclear Information System (INIS)
Avila, Ruben; Cabello-González, Ares; Ramos, Eduardo
2013-01-01
Highlights: • The Tau-Chebyshev method solves the linear fluid flow equations in spherical shells. • The fluid motion is driven by a central force proportional to the radial position. • The full Navier–Stokes equations are solved by the spectral element method. • The linear results are verified with the solution of the Navier–Stokes equations. • The solution of the linear problems is used to initiate non-linear calculations. -- Abstract: The onset of thermal convection in a non-rotating spherical shell is investigated using linear theory. The Tau-Chebyshev spectral method is used to integrate the linearized equations. We investigate the onset of thermal convection by considering two cases of the radial gravitational field (i) a local acceleration, acting radially inward, that is proportional to the distance from the center r, and (ii) a radial gravitational central force that is proportional to r −n . The former case has been widely analyzed in the literature, because it constitutes a simplified model that is usually used, in astrophysics and geophysics, and is studied here to validate the numerical method. The latter case was analyzed since the case n = 5 has been experimentally realized (by means of the dielectrophoretic effect) under microgravity condition, in the experimental container called GeoFlow, inside the International Space Station. Our study is aimed to clarify the role of (i) a radially inward central force (either proportional to r or to r −n ), (ii) a base conductive temperature distribution provided by either a uniform heat source or an imposed temperature difference between outer and inner spheres, and (iii) the aspect ratio η (ratio of the radii of the inner and outer spheres), on the critical Rayleigh number. In all cases the surface of the spheres has been assumed to be rigid. The results obtained with the linear theory based on the Tau-Chebyshev spectral method are compared with those of the integration of the full non
THE OCCURRENCE OF THE RADIAL CLUB HAND IN CHILDREN WITH DIFFERENT SYNDROMES
Directory of Open Access Journals (Sweden)
Sergey Ivanovich Golyana
2013-03-01
Full Text Available Radial club hand is a developmental anomaly of the upper extremity, being characterized as a longitudinal underdevelopment of a forearm and a hand on the radial surface, consisting in a hypo-/ aplazy radial bone and the thumb of various degree of expressiveness. Characteristic symptoms of this developmental anomaly are: shortening and bow-shaped curvature of a forearm, palmar and radial deviation of a hand, underdevelopment of the thumb from its proximal departments and structures, anomaly of development of three-phalanx fingers of a hand (is more often than the 2-4th, violation of a cosmetic condition and functionality of the affected segment. From 2000 for 2012 in FSI SRICO n.a. H.Turner examination and treatment of 23 children with various syndromes at which the radial club hand was revealed are conducted. The main syndromes at which it is revealed radial club hand - Holt-Orama syndrome, TAR- syndrome and VACTERL syndrome. Tactics and techniques of surgical treatment of a radial club hand it various syndromes most often don’t differ from treatment of other types of a radial club hand though demand an individual approach depending on severity and a type of deformation of the upper extremity.
The effect of radial migration on galactic disks
International Nuclear Information System (INIS)
Vera-Ciro, Carlos; D'Onghia, Elena; Navarro, Julio; Abadi, Mario
2014-01-01
We study the radial migration of stars driven by recurring multi-arm spiral features in an exponential disk embedded in a dark matter halo. The spiral perturbations redistribute angular momentum within the disk and lead to substantial radial displacements of individual stars, in a manner that largely preserves the circularity of their orbits and that results, after 5 Gyr (∼40 full rotations at the disk scale length), in little radial heating and no appreciable changes to the vertical or radial structure of the disk. Our results clarify a number of issues related to the spatial distribution and kinematics of migrators. In particular, we find that migrators are a heavily biased subset of stars with preferentially low vertical velocity dispersions. This 'provenance bias' for migrators is not surprising in hindsight, for stars with small vertical excursions spend more time near the disk plane, and thus respond more readily to non-axisymmetric perturbations. We also find that the vertical velocity dispersion of outward migrators always decreases, whereas the opposite holds for inward migrators. To first order, newly arrived migrators simply replace stars that have migrated off to other radii, thus inheriting the vertical bias of the latter. Extreme migrators might therefore be recognized, if present, by the unexpectedly small amplitude of their vertical excursions. Our results show that migration, understood as changes in angular momentum that preserve circularity, can strongly affect the thin disk, but cast doubts on models that envision the Galactic thick disk as a relic of radial migration.
Rayleigh-Taylor instability of cylindrical jets with radial motion
International Nuclear Information System (INIS)
Chen, X.M.; Schrock, V.E.; Peterson, P.F.
1997-01-01
Rayleigh-Taylor instability of an interface between fluids with different densities subjected to acceleration normal to itself has interested researchers for almost a century. The classic analyses of a flat interface by Rayleigh and Taylor have shown that this type of instability depends on the direction of acceleration and the density differences of the two fluids. Plesset later analyzed the stability of a spherically symmetric flows (and a spherical interface) and concluded that the instability also depends on the velocity of the interface as well as the direction and magnitude of radial acceleration. The instability induced by radial motion in cylindrical systems seems to have been neglected by previous researchers. This paper analyzes the Rayleigh-Taylor type of instability for a cylindrical surface with radial motions. The results of the analysis show that, like the spherical case, the radial velocity also plays an important role. As an application, the example of a liquid jet surface in an Inertial Confinement Fusion (ICF) reactor design is analyzed. (orig.)
Directory of Open Access Journals (Sweden)
Jinji Sun
2014-01-01
Full Text Available In this paper, a novel integrated structure is proposed in order to reduce the axial length of the high speed of a magnetically suspended motor (HSMSM to ensure the maximum speed, which combines radial displacement sensor probes and the permanent magnet biased radial magnetic bearing in HSMSM. The sensor probes are integrated in the magnetic bearing, and the sensor preamplifiers are placed in the control system of the HSMSM, separate from the sensor probes. The proposed integrated structure can save space in HSMSMs, improve the working frequency, reduce the influence of temperature on the sensor circuit, and improve the stability of HSMSMs.
Radial-piston pump for drive of test machines
Nizhegorodov, A. I.; Gavrilin, A. N.; Moyzes, B. B.; Cherkasov, A. I.; Zharkevich, O. M.; Zhetessova, G. S.; Savelyeva, N. A.
2018-01-01
The article reviews the development of radial-piston pump with phase control and alternating-flow mode for seismic-testing platforms and other test machines. The prospects for use of the developed device are proved. It is noted that the method of frequency modulation with the detection of the natural frequencies is easily realized by using the radial-piston pump. The prospects of further research are given proof.
Controlling of density uniformity of polyacrylate foams
International Nuclear Information System (INIS)
Shan Wenwen; Yuan Baohe; Wang Yanhong; Xu Jiayun; Zhang Lin
2010-01-01
The density non-uniformity existing in most low-density foams will affect performance of the foams. The trimethylolpropane trimethacrylate (TMPTA) foam targets were prepared and controlling methods of the foams, density uniformity were explored together with its forming mechanism. It has been found that the UV-light with high intensity can improve the distribution uniformity of the free radicals induced by UV photons in the solvents, thus improve the density uniformity of the foams. In addition, container wall would influence the concentration distribution of the solution, which affects the density uniformity of the foams. Thus, the UV-light with high intensity was chosen together with polytetrafluoroethylene molds instead of glass molds to prepare the foams with the density non-uniformity less than 10%. β-ray detection technology was used to measure the density uniformity of the TMPTA foams with the density in the range of 10 to 100 mg · cm -3 , and the results show that the lower the foam density is, the worse the density uniformity is. (authors)
Douma, M.; Ligierko, G.; Angelov, I.
2008-10-01
The need for information has increased exponentially over the past decades. The current systems for constructing, exploring, classifying, organizing, and searching information face the growing challenge of enabling their users to operate efficiently and intuitively in knowledge-heavy environments. This paper presents SpicyNodes, an advanced user interface for difficult interaction contexts. It is based on an underlying structure known as a radial map, which allows users to manipulate and interact in a natural manner with entities called nodes. This technology overcomes certain limitations of existing solutions and solves the problem of browsing complex sets of linked information. SpicyNodes is also an organic system that projects users into a living space, stimulating exploratory behavior and fostering creative thought. Our interactive radial layout is used for educational purposes and has the potential for numerous other applications.
Preliminary study of S-CO{sub 2} cycle control logic for part load operation
Energy Technology Data Exchange (ETDEWEB)
Ahn, Yoonhan; Lee, Jeong Ik [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)
2016-05-15
The benefits of S-CO{sub 2} cycle are relatively high efficiency under the mild turbine inlet temperature region, simple layout configuration and small foot-print. In addition, the safety of the SFR system can be inherently enhanced as the violent sodium-water reaction can be substituted with the mild sodium-CO{sub 2} reaction. 75MWe S-CO{sub 2} recompression cycle with radial type turbomachineries and PCHE was designed. Under various part load conditions (30-100% thermal load), off-design performance of the designed system was assessed, and different control logics were first tested. It was identified that the inventory control strategy is the most efficient logic for the part load operation. In the system operation, the compressor surge condition is seriously considered and controlled to avoid the system damage.
Long-term monitoring FBG-based cable load sensor
Zhang, Zhichun; Zhou, Zhi; Wang, Chuan; Ou, Jinping
2006-03-01
Stay cables are the main load-bearing components of stayed-cable bridges. The cables stress status is an important factor to the stayed-cable bridge structure safety evaluation. So it's very important not only to the bridge construction, but also to the long-term safety evaluation for the bridge structure in-service. The accurate measurement for cable load depends on an effective sensor, especially to meet the long time durability and measurement demand. FBG, for its great advantage of corrosion resistance, absolute measurement, high accuracy, electro-magnetic resistance, quasi-distribution sensing, absolute measurement and so on, is the most promising sensor, which can cater for the cable force monitoring. In this paper, a load sensor has been developed, which is made up of a bushing elastic supporting body, 4 FBGs uniformly-spaced attached outside of the bushing supporting body, and a temperature compensation FBG for other four FBGs, moreover a cover for protection of FBGs. Firstly, the sensor measuring principle is analyzed, and relationship equation of FBG wavelength shifts and extrinsic load has also been gotten. And then the sensor calibration experiments of a steel cable stretching test with the FBG load sensor and a reference electric pressure sensor is finished, and the results shows excellent linearity of extrinsic load and FBG wavelength shifts, and good repeatability, which indicates that such kind of FBG-based load sensor is suitable for load measurement, especially for long-term, real time monitoring of stay-cables.
A novel integrated 4-DOF radial hybrid magnetic bearing for MSCMG
Energy Technology Data Exchange (ETDEWEB)
Jinji, Sun; Ziyan, Ju [School of Instrumentation Science & Opto-electronics Engineering, Beijing University of Aeronautics and Astronautics, Science and Technology on Inertial Laboratory, Beijing 100191 (China); Weitao, Han, E-mail: hanweitaotao@163.com [CRRC Qingdao Sifang CO., LTD, Qingdao 266111 (China); Gang, Liu [School of Instrumentation Science & Opto-electronics Engineering, Beijing University of Aeronautics and Astronautics, Science and Technology on Inertial Laboratory, Beijing 100191 (China)
2017-01-01
This paper proposes a novel integrated radial hybrid magnetic bearing (RHMB) for application with the small-sized magnetically suspended control moment gyroscope (MSCMG), which can control four degrees of freedom (4-DOFs), including two radial translational DOFs and two radial tilting DOFs, and provide the axial passive resilience. The configuration and working principle of the RHMB are introduced. Mathematical models of radial force, axial resilience and moment are established by using equivalent magnetic circuit method (EMCM), from which the radial force–radial displacement, radial force–current relationships are derived, as well as axial resilience–axial displacement, moment–tilting angle and moment–current. Finite element method (FEM) is also applied to analyze the performance and characteristics of the RHMB. The analysis results are in good agreement with that calculated by the EMCM, which is helpful in designing, optimizing and controlling the RHMB. The comparisons between the performances of the integrated 4-DOF RHMB and the traditional 4-DOF RHMB are made. The contrast results indicate that the proposed integrated 4-DOF RHMB possesses better performance compared to the traditional structure, such as copper loss, current stiffness, and tilting current stiffness. - Highlights: • An integrated 4-DOF RHMB is proposed for the small-sized MSCMG. • The 4-DOF RHMB has good linear force–displacement and force–current characteristics. • The RHMB has good linear moment–current and the moment–tilting angle characteristic.
MRI of radial displacement of the meniscus in the knee
International Nuclear Information System (INIS)
Chen Jian; Lv Houshan; Lao Shan; Guan Zhenpeng; Hong Nan; Liang Hao
2006-01-01
Objective: To describe the phenomenon of radial displacement of the meniscus of the knees in the study population with MR imaging, and to establish MRI diagnostic criteria for radial displacement of the meniscus and displacement index. Methods: MR signs of radial displacement of the meniscus were evaluated retrospectively in 398 patients with knee symptoms who were examined with non- weight bearing MR images from Jan. 2000 to Feb. 2004. The patients younger than 18 years old, with joint effusion or serious arthropathy were excluded and 312 patients were eligible to be enrolled in this study. The criterion for radial displacement of the meniscus was defined as the location of the edge of meniscal body beyond the femoral and tibial outer border line. A displacement index, defined as the ratio of meniscal overhang to meniscal width, was used to quantify meniscal displacement. Results: The prevalence of radial displacement of the meniscus was 16.7% (52/312) and 13.9% (21/151) in right knee and 19.3% (31/161 )in left knee, respectively. There was no significant difference between left and right knee (χ 2 =1.60, P>0.05) and the ratio between medial and lateral meniscus was 7.8:1. The average displacement index was 0.54±0.24. The displacement indices were significant higher in older group (F=3.63, P<0.05). The incidence and indices of radial displacement of the meniscus for patients under or above 50 year older were 12.0%(17/142), 0.46±0.22 and 20.6% (35/170), 0.64±0.20, respectively. Difference was highly significant (t=0.84, P<0.01). Conclusion: It was concluded that radial displacement of the meniscus in knees was not a rare finding with MR imaging in patients with knee symptoms. The incidence increased in older age group. Further investigations were recommended to understand the etiology and clinical significance of the phenomenon of radial displacement of the meniscus. (authors)
Directory of Open Access Journals (Sweden)
M. F. Akorede
2017-06-01
Full Text Available The intent of power distribution companies (DISCOs is to deliver electric power to their customers in an efficient and reliable manner – with minimal energy loss cost. One major way to minimise power loss on a given power system is to install distributed generation (DG units on the distribution networks. However, to maximise benefits, it is highly crucial for a DISCO to ensure that these DG units are of optimal size and sited in the best locations on the network. This paper gives an overview of a software package developed in this study, called Power System Analysis and DG Optimisation Tool (PFADOT. The main purpose of the graphical user interface-based package is to guide a DISCO in finding the optimal size and location for DG placement in radial distribution networks. The package, which is also suitable for load flow analysis, employs the GUI feature of MATLAB. Three objective functions are formulated into a single optimisation problem and solved with fuzzy genetic algorithm to simultaneously obtain DG optimal size and location. The accuracy and reliability of the developed tool was validated using several radial test systems, and the results obtained are evaluated against the existing similar package cited in the literature, which are impressive and computationally efficient.
International Nuclear Information System (INIS)
Sahoo, N.C.; Prasad, K.
2006-01-01
This paper presents a fuzzy genetic approach for reconfiguration of radial distribution systems (RDS) so as to maximize the voltage stability of the network for a specific set of loads. The network reconfiguration involves a mechanism for selection of the best set of branches to be opened, one from each loop, such that the reconfigured RDS possesses desired performance characteristics. This discrete solution space is better handled by the proposed scheme, which maximizes a suitable optimizing function (computed using two different approaches). In the first approach, this function is chosen as the average of a voltage stability index of all the buses in the RDS, while in the second approach, the complete RDS is reduced to a two bus equivalent system and the optimizing function is the voltage stability index of this reduced two bus system. The fuzzy genetic algorithm uses a suitable coding and decoding scheme for maintaining the radial nature of the network at every stage of genetic evolution, and it also uses a fuzzy rule based mutation controller for efficient search of the solution space. This method, tested on 69 bus and 33 bus RDSs, shows promising results for the both approaches. It is also observed that the network losses are reduced when the voltage stability is enhanced by the network reconfiguration
Two Stage Secure Dynamic Load Balancing Architecture for SIP Server Clusters
Directory of Open Access Journals (Sweden)
G. Vennila
2014-08-01
Full Text Available Session Initiation Protocol (SIP is a signaling protocol emerged with an aim to enhance the IP network capabilities in terms of complex service provision. SIP server scalability with load balancing has a greater concern due to the dramatic increase in SIP service demand. Load balancing of session method (request/response and security measures optimizes the SIP server to regulate of network traffic in Voice over Internet Protocol (VoIP. Establishing a honeywall prior to the load balancer significantly reduces SIP traffic and drops inbound malicious load. In this paper, we propose Active Least Call in SIP Server (ALC_Server algorithm fulfills objectives like congestion avoidance, improved response times, throughput, resource utilization, reducing server faults, scalability and protection of SIP call from DoS attacks. From the test bed, the proposed two-tier architecture demonstrates that the ALC_Server method dynamically controls the overload and provides robust security, uniform load distribution for SIP servers.
Vortex Whistle in Radial Intake
National Research Council Canada - National Science Library
Tse, Man-Chun
2004-01-01
In a radial-to-axial intake with inlet guide vanes (IGV) at the entry, a strong flow circulation Gamma can be generated from the tangential flow components created by the IGVs when their setting exceed about halfclosing (approx. 45 deg...
Radial force measurement of endovascular stents: Influence of stent design and diameter.
Matsumoto, Takuya; Matsubara, Yutaka; Aoyagi, Yukihiko; Matsuda, Daisuke; Okadome, Jun; Morisaki, Koichi; Inoue, Kentarou; Tanaka, Shinichi; Ohkusa, Tomoko; Maehara, Yoshihiko
2016-04-01
Angioplasty and endovascular stent placement is used in case to rescue the coverage of main branches to supply blood to brain from aortic arch in thoracic endovascular aortic repair. This study assessed mechanical properties, especially differences in radial force, of different endovascular and thoracic stents. We analyzed the radial force of three stent models (Epic, E-Luminexx and SMART) stents using radial force-tester method in single or overlapping conditions. We also analyzed radial force in three thoracic stents using Mylar film testing method: conformable Gore-TAG, Relay, and Valiant Thoracic Stent Graft. Overlapping SMART stents had greater radial force than overlapping Epic or Luminexx stents (P stents was greater than that of all three endovascular stents (P stents, site of deployment, and layer characteristics. In clinical settings, an understanding of the mechanical characteristics, including radial force, is important in choosing a stent for each patient. © The Author(s) 2015.
Energy Technology Data Exchange (ETDEWEB)
Martin del Campo M, C.; Carmona H, R.; Oropeza C, I.P. [UNAM, Paseo Cuauhnahuac 8532, 62550 Jiutepec, Morelos (Mexico)]. e-mail: cmcm@fi-b.unam.mx
2006-07-01
The development of the application of the Genetic Algorithms (GA) to the optimization of the radial distribution of enrichment in a cell of fuel of a BWR (Boiling Water Reactor) is presented. The optimization process it was ties to the HELIOS simulator, which is a transport code of neutron simulation of fuel cells that has been validated for the calculation of nuclear banks for BWRs. With heterogeneous radial designs can improve the radial distribution of the power, for what the radial design of fuel has a strong influence in the global design of fuel recharges. The optimum radial distribution of fuel bars is looked for with different enrichments of U{sup 235} and contents of consumable poison. For it is necessary to define the representation of the solution, the objective function and the implementation of the specific optimization process to the solution of the problem. The optimization process it was coded in 'C' language, it was automated the creation of the entrances to the simulator, the execution of the simulator and the extraction, in the exit of the simulator, of the parameters that intervene in the objective function. The objective function includes four parameters: average enrichment of the cell, average gadolinia concentration of the cell, peak factor of radial power and k-infinite multiplication factor. To be able to calculate the parameters that intervene in the objective function, the one evaluation process of GA was ties to the HELIOS code executed in a Compaq Alpha workstation. It was applied to the design of a fuel cell of 10 x 10 that it can be employee in the fuel assemble designs that are used at the moment in the Laguna Verde Nucleo electric Central. Its were considered 10 different fuel compositions which four contain gadolinia. Three heuristic rules that consist in prohibiting the placement of bars with gadolinia in the ends of the cell, to place the compositions with the smallest enrichment in the corners of the cell and to fix
7 CFR 1006.61 - Computation of uniform prices.
2010-01-01
..., the market administrator shall compute a uniform butterfat price, a uniform skim milk price, and a... section. (b) Uniform skim milk price. The uniform skim milk price per hundredweight, rounded to the... paragraph (a) of this section times 3.5 pounds of butterfat; and (2) Multiply the uniform skim milk price...
7 CFR 1131.61 - Computation of uniform prices.
2010-01-01
..., the market administrator shall compute a uniform butterfat price, a uniform skim milk price, and a... section. (b) Uniform skim milk price. The uniform skim milk price per hundredweight, rounded to the... paragraph (a) of this section times 3.5 pounds of butterfat; and (2) Multiply the uniform skim milk price...
7 CFR 1007.61 - Computation of uniform prices.
2010-01-01
..., the market administrator shall compute a uniform butterfat price, a uniform skim milk price, and a... section. (b) Uniform skim milk price. The uniform skim milk price per hundredweight, rounded to the... paragraph (a) of this section times 3.5 pounds of butterfat; and (2) Multiply the uniform skim milk price...
Directory of Open Access Journals (Sweden)
Krishna Kumar
2010-11-01
Full Text Available Radial spasm is often very prolonged and painful to the patient. Here, we describe a novel way to deal with the same. The total spasm lasted over 4 hours. A 3.4 6 JR catheter was introduced via the femoral route and papav arine one ampoule was injected directly into the right subclavian artery. After about 10 min we were able to pull out the radial catheter. Radial angiography is a simple procedure with reportedly less complications 1,2. How ever ,it has one major complication radial spasm. We describe here a patient with radial spasm that persisted for more than 2 hours and how we dealt with it.
Uniformity in radiation protection legislation in Australia: a case study
International Nuclear Information System (INIS)
Robotham, F.P.J.
2003-01-01
This paper describes a recent licensing/approval process conducted by a company that has three plants utilizing large sealed sources of Cobalt-60, in one case approximately 70PBq. The company has operated successfully in one Australian State since 1971 and in a second since 1985. By 1999 it became apparent that there was sufficient business to warrant the opening of a third plant in a third Australian State. The plant chosen has a design capacity of 185PBq and an initial loading of 1 IPBq. This paper describes some of the licensing process and demonstrates, I believe, the urgent need for both uniformity in Australian Radiation Safety Legislation and consistency in interpretation and implementation. Copyright (2003) Australasian Radiation Protection Society Inc
7 CFR 1005.61 - Computation of uniform prices.
2010-01-01
... month, the market administrator shall compute a uniform butterfat price, a uniform skim milk price, and...) and (a)(2) of this section. (b) Uniform skim milk price. The uniform skim milk price per hundredweight... paragraph (a) of this section times 3.5 pounds of butterfat; and (2) Multiply the uniform skim milk price...
The First Experience of Triple Nerve Transfer in Proximal Radial Nerve Palsy.
Emamhadi, Mohammadreza; Andalib, Sasan
2018-01-01
Injury to distal portion of posterior cord of brachial plexus leads to palsy of radial and axillary nerves. Symptoms are usually motor deficits of the deltoid muscle; triceps brachii muscle; and extensor muscles of the wrist, thumb, and fingers. Tendon transfers, nerve grafts, and nerve transfers are options for surgical treatment of proximal radial nerve palsy to restore some motor functions. Tendon transfer is painful, requires a long immobilization, and decreases donor muscle strength; nevertheless, nerve transfer produces promising outcomes. We present a patient with proximal radial nerve palsy following a blunt injury undergoing triple nerve transfer. The patient was involved in a motorcycle accident with complete palsy of the radial and axillary nerves. After 6 months, on admission, he showed spontaneous recovery of axillary nerve palsy, but radial nerve palsy remained. We performed triple nerve transfer, fascicle of ulnar nerve to long head of the triceps branch of radial nerve, flexor digitorum superficialis branch of median nerve to extensor carpi radialis brevis branch of radial nerve, and flexor carpi radialis branch of median nerve to posterior interosseous nerve, for restoration of elbow, wrist, and finger extensions, respectively. Our experience confirmed functional elbow, wrist, and finger extensions in the patient. Triple nerve transfer restores functions of the upper limb in patients with debilitating radial nerve palsy after blunt injuries. Copyright © 2017 Elsevier Inc. All rights reserved.
Development of a Radial Deconsolidation Method
Energy Technology Data Exchange (ETDEWEB)
Helmreich, Grant W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Montgomery, Fred C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hunn, John D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
2015-12-01
A series of experiments have been initiated to determine the retention or mobility of fission products* in AGR fuel compacts [Petti, et al. 2010]. This information is needed to refine fission product transport models. The AGR-3/4 irradiation test involved half-inch-long compacts that each contained twenty designed-to-fail (DTF) particles, with 20-μm thick carbon-coated kernels whose coatings were deliberately fabricated such that they would crack under irradiation, providing a known source of post-irradiation isotopes. The DTF particles in these compacts were axially distributed along the compact centerline so that the diffusion of fission products released from the DTF kernels would be radially symmetric [Hunn, et al. 2012; Hunn et al. 2011; Kercher, et al. 2011; Hunn, et al. 2007]. Compacts containing DTF particles were irradiated at Idaho National Laboratory (INL) at the Advanced Test Reactor (ATR) [Collin, 2015]. Analysis of the diffusion of these various post-irradiation isotopes through the compact requires a method to radially deconsolidate the compacts so that nested-annular volumes may be analyzed for post-irradiation isotope inventory in the compact matrix, TRISO outer pyrolytic carbon (OPyC), and DTF kernels. An effective radial deconsolidation method and apparatus appropriate to this application has been developed and parametrically characterized.
Mcgovern, Patrick J.; Solomon, Sean C.
1993-01-01
Magellan radar imaging and topography data are now available for a number of volcanoes on Venus greater than 100 km in radius. These data can be examined to reveal evidence of the flexural response of the lithosphere to the volcanic load. On Venus, erosion and sediment deposition are negligible, so tectonic evidence of deformation around large volcanoes should be evident except where buried by very young flows. Radar images reveal that most tectonic features and flow units on the flanks of these volcanoes have predominantly radial orientations. However, both Tepev Mons in Bell Regio and Sapas Mons in Atla Regio exhibit circumferential graben on their flanks. In addition, images reveal several flow units with an annular character around the north and west flanks of Tepev Mons. This pattern most likely results from ponding of flows in an annular flexural moat. Maat Mons in Atla Regio and Sif Mons in Eistla Regio are examples of volcanoes that lack circumferential graben and annular flows; discernible flow units and fractures on these constructs appear to be predominantly radial. Altimetry data can also provide evidence of flexural response. Tepev Mons is partially encircled by depressions that may be sections of a flexural moat that has not been completely filled. The locations of these depressions generally coincide with the annular flows described above. There is weaker evidence for such depressions around Maat Mons as well. The lack of circumferential tectonic features around most volcanoes on Venus might be explained by gradual moat filling and coverage by radial flows. The depressions around Tepev (and possible Maat) may indicate that this process is currently continuing. We use analytic models of plate flexure in an axisymmetric geometry to constrain the elastic plate thickness supporting Tepev Mons. If we consider the outer radius of the ponded flows to be the edge of a moat, we find that models with elastic plate thickness of 10-20 km fit best. Finite element
Multicycle Optimization of Advanced Gas-Cooled Reactor Loading Patterns Using Genetic Algorithms
International Nuclear Information System (INIS)
Ziver, A. Kemal; Carter, Jonathan N.; Pain, Christopher C.; Oliveira, Cassiano R.E. de; Goddard, Antony J. H.; Overton, Richard S.
2003-01-01
A genetic algorithm (GA)-based optimizer (GAOPT) has been developed for in-core fuel management of advanced gas-cooled reactors (AGRs) at HINKLEY B and HARTLEPOOL, which employ on-load and off-load refueling, respectively. The optimizer has been linked to the reactor analysis code PANTHER for the automated evaluation of loading patterns in a two-dimensional geometry, which is collapsed from the three-dimensional reactor model. GAOPT uses a directed stochastic (Monte Carlo) algorithm to generate initial population members, within predetermined constraints, for use in GAs, which apply the standard genetic operators: selection by tournament, crossover, and mutation. The GAOPT is able to generate and optimize loading patterns for successive reactor cycles (multicycle) within acceptable CPU times even on single-processor systems. The algorithm allows radial shuffling of fuel assemblies in a multicycle refueling optimization, which is constructed to aid long-term core management planning decisions. This paper presents the application of the GA-based optimization to two AGR stations, which apply different in-core management operational rules. Results obtained from the testing of GAOPT are discussed
Partially Loaded Cavity Analysis by Using the 2-D FDTD Method
International Nuclear Information System (INIS)
Yao Bin; Zheng Qin-Hong; Peng Jin-Hui; Zhong Ru-Neng; Xiang Tai; Xu Wan-Song
2011-01-01
A compact two-dimensional (2-D) finite-difference time-domain (FDTD) method is proposed to calculate the resonant frequencies and quality factors of a partially loaded cavity that is uniform in the z-direction and has an arbitrary cross section in the x—y plane. With the description of z dependence by k z , the three-dimensional (3-D) problem can be transformed into a 2-D problem. Therefore, less memory and CPU time are required as compared to the conventional 3-D FDTD method. Three representative examples, a half-loaded rectangular cavity, an inhomogeneous cylindrical cavity and a cubic cavity loaded with dielectric post, are presented to validate the utility and efficiency of the proposed method. (cross-disciplinary physics and related areas of science and technology)
Spacetime transformations from a uniformly accelerated frame
International Nuclear Information System (INIS)
Friedman, Yaakov; Scarr, Tzvi
2013-01-01
We use the generalized Fermi–Walker transport to construct a one-parameter family of inertial frames which are instantaneously comoving to a uniformly accelerated observer. We explain the connection between our approach and that of Mashhoon. We show that our solutions of uniformly accelerated motion have constant acceleration in the comoving frame. Assuming the weak hypothesis of locality, we obtain local spacetime transformations from a uniformly accelerated frame K′ to an inertial frame K. The spacetime transformations between two uniformly accelerated frames with the same acceleration are Lorentz. We compute the metric at an arbitrary point of a uniformly accelerated frame. (paper)
Aft-body loading function for penetrators based on the spherical cavity-expansion approximation.
Energy Technology Data Exchange (ETDEWEB)
Longcope, Donald B., Jr.; Warren, Thomas Lynn; Duong, Henry
2009-12-01
In this paper we develop an aft-body loading function for penetration simulations that is based on the spherical cavity-expansion approximation. This loading function assumes that there is a preexisting cavity of radius a{sub o} before the expansion occurs. This causes the radial stress on the cavity surface to be less than what is obtained if the cavity is opened from a zero initial radius. This in turn causes less resistance on the aft body as it penetrates the target which allows for greater rotation of the penetrator. Results from simulations are compared with experimental results for oblique penetration into a concrete target with an unconfined compressive strength of 23 MPa.
Analysis of axial compressive loaded beam under random support excitations
Xiao, Wensheng; Wang, Fengde; Liu, Jian
2017-12-01
An analytical procedure to investigate the response spectrum of a uniform Bernoulli-Euler beam with axial compressive load subjected to random support excitations is implemented based on the Mindlin-Goodman method and the mode superposition method in the frequency domain. The random response spectrum of the simply supported beam subjected to white noise excitation and to Pierson-Moskowitz spectrum excitation is investigated, and the characteristics of the response spectrum are further explored. Moreover, the effect of axial compressive load is studied and a method to determine the axial load is proposed. The research results show that the response spectrum mainly consists of the beam's additional displacement response spectrum when the excitation is white noise; however, the quasi-static displacement response spectrum is the main component when the excitation is the Pierson-Moskowitz spectrum. Under white noise excitation, the amplitude of the power spectral density function decreased as the axial compressive load increased, while the frequency band of the vibration response spectrum increased with the increase of axial compressive load.
Directory of Open Access Journals (Sweden)
Jaime Alberto Echeverri Arias
2009-07-01
Full Text Available La eliminación del ruido impulsivo es un problema clásico del procesado no lineal para el mejoramiento de imágenes y las funciones de base radial de soporte global son útiles para enfrentarlo. Este trabajo presenta una técnica de interpolación que disminuye eficientemente el ruido impulsivo en imágenes, mediante el uso de interpolante obtenido por funciones de base radial en el marco de la investigación enfocada en el desarrollo de un Sistema de recuperación de imágenes de recursos acuáticos amazónicos. Esta técnica primero etiqueta los píxeles de la imagen que son ruidosos y, mediante la interpolación, genera un valor de reconstrucción de dicho píxel usando sus vecinos. Los resultados obtenidos son comparables y muchas veces mejores que otras técnicas ya publicadas y reconocidas. Según el análisis de resultados, se puede aplicar a imágenes con altas tasas de ruido, manteniendo un bajo error de reconstrucción de los píxeles "ruidosos", así como la calidad visual.Global support radial base functions are effective in eliminating impulsive noise in non-linear processing. This paper introduces an interpolation technique which efficiently reduces image impulsive noise by means of an interpolant obtained through radial base functions. These functions have been used in a research project designed to develop a system for the recovery of images of Amazonian aquatic resources. This technique starts with the tagging by interpolation of noisy image pixels. Thus, a value of reconstruction for the noisy pixels is generated using neighboring pixels. The results obtained with this technique have proved comparable and often better than those obtained with previously known techniques. According to results analysis, this technique can be successfully applied on images with high noise levels. The results are low error in noisy pixel reconstruction and better visual quality.
Sirenomelia with radial dysplasia.
Kulkarni, M L; Abdul Manaf, K M; Prasannakumar, D G; Kulkarni, Preethi M
2004-05-01
Sirenomelia is a rare anomaly usually associated with other multiple malformations. In this communication the authors report a case of sirenomelia associated with multiple malformations, which include radial hypoplasia also. Though several theories have been proposed regarding the etiology of multiple malformation syndromes in the past, the recent theory of primary developmental defect during blastogenesis holds good in this case.
Introducing radiality constraints in capacitated location-routing problems
Directory of Open Access Journals (Sweden)
Eliana Mirledy Toro Ocampo
2017-03-01
Full Text Available In this paper, we introduce a unified mathematical formulation for the Capacitated Vehicle Routing Problem (CVRP and for the Capacitated Location Routing Problem (CLRP, adopting radiality constraints in order to guarantee valid routes and eliminate subtours. This idea is inspired by formulations already employed in electric power distribution networks, which requires a radial topology in its operation. The results show that the proposed formulation greatly improves the convergence of the solver.
Analysis on Coupled Vibration of a Radially Polarized Piezoelectric Cylindrical Transducer
Directory of Open Access Journals (Sweden)
Jie Xu
2017-12-01
Full Text Available Coupled vibration of a radially polarized piezoelectric cylindrical transducer is analyzed with the mechanical coupling coefficient method. The method has been utilized to analyze the metal cylindrical transducer and the axially polarized piezoelectric cylindrical transducer. In this method, the mechanical coupling coefficient is introduced and defined as the stress ratio in different directions. Coupled vibration of the cylindrical transducer is regarded as the interaction of the plane radial vibration of a ring and the longitudinal vibration of a tube. For the radially polarized piezoelectric cylindrical transducer, the radial and longitudinal electric admittances as functions of mechanical coupling coefficients and angular frequencies are derived, respectively. The resonance frequency equations are obtained. The dependence of resonance frequency and mechanical coupling coefficient on aspect ratio is studied. Vibrational distributions on the surfaces of the cylindrical transducer are presented with experimental measurement. On the support of experiments, this work is verified and provides a theoretical foundation for the analysis and design of the radially polarized piezoelectric cylindrical transducer.
Elastic stability of biaxially loaded longitudinally stiffened composite structures.
Viswanathan, A. V.; Tamekuni, M.; Tripp, L. L.
1973-01-01
A linear analysis method is presented for the elastic stability of structures of uniform cross section, that may be idealized as an assemblage of laminated plate-strips, flat and curved, and beams. Each plate-strip and beam covers the entire length of the structure and is simply supported on the edges normal to the longitudinal axis. Arbitrary boundary conditions may be specified on any external longitudinal side of plate-strips. The structure or selected plate-strips may be loaded in any desired combination of inplane biaxial loads. The analysis simultaneously considers all modes of instability and is applicable for the buckling of laminated composite structures. Some numerical results are presented to indicate possible applications.
International Nuclear Information System (INIS)
Ohta, M.M.
1978-02-01
In the spring of 1974, WNRE began development and demonstration of a dry storage concept, called the concrete canister, as a possible alternative to storage of irradiated CANDU fuel in water pools. The canister is a thick-walled concrete monolith containing baskets of fuel in the dry state. The decay heat from the fuel is dissipated to the environment by natural heat transfer. Four canisters were designed and constructed. Two canisters containing electric heaters have been subjected to heat loads of 2.5 times the design, ramp heat-load cycling, and simulated weathering tests. The other two canisters were loaded with irradiated fuel, one containing fuel bundles of uniform decay heat and the other containing bundles of non-uniform decay heat in a non-symmetrical radial and axial array. The collected data were used to verify the analytical tools for prediction of effectiveness of heat transfer and radiation shielding and to verify the design of the basket and canisters. The demonstration canisters have shown that this concept is a viable alternative to water pools for the storage of irradiated CANDU fuel. (author)
Energy Technology Data Exchange (ETDEWEB)
Payan, J
1994-05-01
After a review of turbulence and transport phenomena in tokamak plasmas and the radial electric field shear effect in various tokamaks, experimental measurements obtained at Tore Supra by the means of the ALTAIR plasma diagnostic technique, are presented. Electronic drift waves destabilization mechanisms, which are the main features that could describe the experimentally observed microturbulence, are then examined. The effect of a radial electric field shear on electronic drift waves is then introduced, and results with ohmic heating are studied together with relations between turbulence and transport. The possible existence of ionic waves is rejected, and a spectral frequency modelization is presented, based on the existence of an electric field sheared radial profile. The position of the inversion point of this field is calculated for different values of the mean density and the plasma current, and the modelization is applied to the TEXT tokamak. The radial electric field at Tore Supra is then estimated. The effect of the ergodic divertor on turbulence and abnormal transport is then described and the density fluctuation radial profile in presence of the ergodic divertor is modelled. 80 figs., 120 refs.
International Nuclear Information System (INIS)
Maslov, V.I.; Barchuk, S.V.; Lapshin, V.I.; Volkov, E.D.; Melentsov, Yu.V.
2006-01-01
It is shown, that at development of instability due to a radial gradient of density in the crossed electric and magnetic fields in nuclear fusion installations ordering convective cells can be excited. It provides anomalous particle transport. The spatial structures of these convective cells have been constructed. The radial dimensions of these convective cells depend on their amplitudes and on a radial gradient of density. The convective-diffusion equation for radial dynamics of the electrons has been derived. At the certain value of the universal controlling parameter, the convective cell excitation and the anomalous radial transport are suppressed. (author)
Energy Technology Data Exchange (ETDEWEB)
Zupančič, Matevž, E-mail: matevz.zupancic@fs.uni-lj.si; Može, Matic; Gregorčič, Peter; Golobič, Iztok
2017-03-31
Highlights: • Surfaces with periodically changed wettability were produced by a ns marking laser. • Heat transfer was investigated on uniformly and non-uniformly wettable surfaces. • Microporous surfaces with non-uniform wettability enhance boiling heat transfer. • The most bubble nucleations were observed in the vicinity of the microcavities. • Results agree with the predictions of the nucleation criteria. - Abstract: Microstructured uniformly and non-uniformly wettable surfaces were created on 25-μm-thin stainless steel foils by laser texturing using a marking nanosecond Nd:YAG laser (λ = 1064 nm) and utilizing various laser fluences and scan line separations. High-speed photography and high-speed IR thermography were used to investigate nucleate boiling heat transfer on the microstructured surfaces. The most pronounced results were obtained on a surface with non-uniform microstructure and non-uniform wettability. The obtained results show up to a 110% higher heat transfer coefficients and 20–40 times higher nucleation site densities compared to the untextured surface. We show that the number of active nucleation sites is significantly increased in the vicinity of microcavities that appeared in areas with the smallest (10 μm) scan line separation. Furthermore, this confirms the predictions of nucleation criteria and proves that straightforward, cost-effective nanosecond laser texturing allows the production of cavities with diameters of up to a few micrometers and surfaces with non-uniform wettability. Additionally, this opens up important possibilities for a more deterministic control over the complex boiling process.
Non-uniform shrinkage of multiple-walled carbon nanotubes under in situ electron beam irradiation
Energy Technology Data Exchange (ETDEWEB)
Li, Lunxiong [South China Normal University, Brain Science Institute, Guangzhou (China); Xiamen University, China-Australia Joint Laboratory for Functional Nanomaterials and Physics Department, Xiamen (China); Su, Jiangbin [Xiamen University, China-Australia Joint Laboratory for Functional Nanomaterials and Physics Department, Xiamen (China); Chang Zhou University, School of Mathematics and Physics, Changzhou (China); Zhu, Xianfang [Xiamen University, China-Australia Joint Laboratory for Functional Nanomaterials and Physics Department, Xiamen (China)
2016-10-15
Instability of multiple-walled carbon nanotubes (MWCNTs) was investigated by in situ transmission electron microscopy at room temperature. Specially, the non-uniform shrinkage of tubes was found: The pristine MWCNT shrank preferentially in its axial direction from the most curved free cap end of the tube, but the shrinkage of the tube diameter was offset by the axial shrinkage: For the complex MWCNT, the two inner MWCNTs also preferentially axially shrank from their most curved cap ends and separated from each other. However, for the effect of the radial pressure from the out walls which enveloped the two inner tubes and the tube amorphization, the two inner tubes were extruded to come close to each other and finally touched again. The new ''evaporation'' and ''diffusion'' mechanisms of carbon atoms as driven by the nano-curvature of CNT and the electron beam-induced athermal activation were suggested to explain the above phenomena. (orig.)
Plasma Signatures of Radial Field Power Dropouts
International Nuclear Information System (INIS)
Lucek, E.A.; Horbury, T.S.; Balogh, A.; McComas, D.J.
1998-01-01
A class of small scale structures, with a near-radial magnetic field and a drop in magnetic field fluctuation power, have recently been identified in the polar solar wind. An earlier study of 24 events, each lasting for 6 hours or more, identified no clear plasma signature. In an extension of that work, radial intervals lasting for 4 hours or more (89 in total), have been used to search for a statistically significant plasma signature. It was found that, despite considerable variations between intervals, there was a small but significant drop, on average, in plasma temperature, density and β during these events
Reble, a radially converging electron beam accelerator
International Nuclear Information System (INIS)
Ramirez, J.J.; Prestwich, K.R.
1976-01-01
The Reble accelerator at Sandia Laboratories is described. This accelerator was developed to provide an experimental source for studying the relevant diode physics, beam propagation, beam energy deposition in a gas using a radially converging e-beam. The nominal parameters for Reble are 1 MV, 200 kA, 20 ns e-beam pulse. The anode and cathode are concentric cylinders with the anode as the inner cylinder. The radial beam can be propagated through the thin foil anode into the laser gas volume. The design and performance of the various components of the accelerator are presented
Stresses and displacements in vessels due to loads imposed by single and multiple piping attachments
International Nuclear Information System (INIS)
Wong, F.M.G.; Craft, W.J.; East, G.H.
1985-01-01
The Fourier solution for thin shell equations models pressure vessels as continuous simply connected surfaces with local loads. The technique allows placement of tractions with combinations of radial, shear, and axial components. Unlike Bijlaard, the solution in this paper includes loads placed at any position along the cylinder. Stiffness and the enhanced load-carrying capacity that internal pressure gives to thin vessels can be simulated. Numerical convergence problems are reduced by an improved displacement-load algorithm, and by use of load sites that allow the circular functions to be compactly grouped. A variety of loading distributions may be analyzed including large and small nozzles near and away from centerlines. Both rectangular and circular attachments are simulated. Through superposition, multiple attachments with their own loads may be examined. The attachments to the vessel may be either rigid or soft. A comparison to analytical results from Bijlaard shows excellent agreement. Comparisons with experimental tests on an API-650 nozzle on a storage tank are in good agreement. Variations between experimental and calculated results are primarily caused by assuming a simply supported base in the calculation, whereas in the experimental test, the base is more nearly fixed
Atmospheric pressure loading effects on Global Positioning System coordinate determinations
Vandam, Tonie M.; Blewitt, Geoffrey; Heflin, Michael B.
1994-01-01
Earth deformation signals caused by atmospheric pressure loading are detected in vertical position estimates at Global Positioning System (GPS) stations. Surface displacements due to changes in atmospheric pressure account for up to 24% of the total variance in the GPS height estimates. The detected loading signals are larger at higher latitudes where pressure variations are greatest; the largest effect is observed at Fairbanks, Alaska (latitude 65 deg), with a signal root mean square (RMS) of 5 mm. Out of 19 continuously operating GPS sites (with a mean of 281 daily solutions per site), 18 show a positive correlation between the GPS vertical estimates and the modeled loading displacements. Accounting for loading reduces the variance of the vertical station positions on 12 of the 19 sites investigated. Removing the modeled pressure loading from GPS determinations of baseline length for baselines longer than 6000 km reduces the variance on 73 of the 117 baselines investigated. The slight increase in variance for some of the sites and baselines is consistent with expected statistical fluctuations. The results from most stations are consistent with approximately 65% of the modeled pressure load being found in the GPS vertical position measurements. Removing an annual signal from both the measured heights and the modeled load time series leaves this value unchanged. The source of the remaining discrepancy between the modeled and observed loading signal may be the result of (1) anisotropic effects in the Earth's loading response, (2) errors in GPS estimates of tropospheric delay, (3) errors in the surface pressure data, or (4) annual signals in the time series of loading and station heights. In addition, we find that using site dependent coefficients, determined by fitting local pressure to the modeled radial displacements, reduces the variance of the measured station heights as well as or better than using the global convolution sum.
International Nuclear Information System (INIS)
Yang, Zhao Jian; Peng, Ze Jun; Kim, Seock Sam
2004-01-01
A model in the form of a Bearing Load Distribution (BLD) matrix in the Multi Bearing Rotor System (MBRS) is established by a transfer matrix equation with the consideration of a bearing load, elevation and uniform load distribution. The concept of Bearing Load Sensitivity (BLS) is proposed and matrices for load and elevation sensitivity are obtained. In order to share MBRS design resources on the internet with remote customers, the basic principle of Remote Computing (RC) based on the internet is introduced ; the RC of the BLD and BLS is achieved by Microsoft Active Server Pages (ASP) technology
24 CFR 5.801 - Uniform financial reporting standards.
2010-04-01
... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Uniform financial reporting... and Urban Development GENERAL HUD PROGRAM REQUIREMENTS; WAIVERS Uniform Financial Reporting Standards § 5.801 Uniform financial reporting standards. (a) Applicability. This subpart H implements uniform...
Observational hints of radial migration in disc galaxies from CALIFA
Ruiz-Lara, T.; Pérez, I.; Florido, E.; Sánchez-Blázquez, P.; Méndez-Abreu, J.; Sánchez-Menguiano, L.; Sánchez, S. F.; Lyubenova, M.; Falcón-Barroso, J.; van de Ven, G.; Marino, R. A.; de Lorenzo-Cáceres, A.; Catalán-Torrecilla, C.; Costantin, L.; Bland-Hawthorn, J.; Galbany, L.; García-Benito, R.; Husemann, B.; Kehrig, C.; Márquez, I.; Mast, D.; Walcher, C. J.; Zibetti, S.; Ziegler, B.
2017-01-01
Context. According to numerical simulations, stars are not always kept at their birth galactocentric distances but they have a tendency to migrate. The importance of this radial migration in shaping galactic light distributions is still unclear. However, if radial migration is indeed important,
Radial mixing of material in the asterodial zone
International Nuclear Information System (INIS)
Ruzmaikina, T.V.; Safronov, V.S.; Weidenschilling, S.J.
1989-01-01
The asteroid belt shows radial zoning of compositional structure. The most abundant types are successively S, C and P types from the inner to the outer parts of the main belt, and D type in the Trojan clouds. Boundaries between compositional zones are not sharp, but gradual transitions over scales ∼1 AU in semimajor axis. The authors examine processes for producing this structure before, during and after the accretion of asteroids. The initial structure is established by temperature and composition gradients in the turbulent solar nebula during the collapse of the presolar cloud. The radial scale of the zoning, comparable to the disk thickness, favors disk models with relatively low turbulent viscosity. Radial decay of solid bodies due to gas drag during settling to the central plane and planetesimal formation probably causes only a small degree of mixing, due to the systematic nature of drag-induced motions
Mixed-Degree Spherical Simplex-Radial Cubature Kalman Filter
Directory of Open Access Journals (Sweden)
Shiyuan Wang
2017-01-01
Full Text Available Conventional low degree spherical simplex-radial cubature Kalman filters often generate low filtering accuracy or even diverge for handling highly nonlinear systems. The high-degree Kalman filters can improve filtering accuracy at the cost of increasing computational complexity; nevertheless their stability will be influenced by the negative weights existing in the high-dimensional systems. To efficiently improve filtering accuracy and stability, a novel mixed-degree spherical simplex-radial cubature Kalman filter (MSSRCKF is proposed in this paper. The accuracy analysis shows that the true posterior mean and covariance calculated by the proposed MSSRCKF can agree accurately with the third-order moment and the second-order moment, respectively. Simulation results show that, in comparison with the conventional spherical simplex-radial cubature Kalman filters that are based on the same degrees, the proposed MSSRCKF can perform superior results from the aspects of filtering accuracy and computational complexity.
Decidability of uniform recurrence of morphic sequences
Durand , Fabien
2012-01-01
We prove that the uniform recurrence of morphic sequences is decidable. For this we show that the number of derived sequences of uniformly recurrent morphic sequences is bounded. As a corollary we obtain that uniformly recurrent morphic sequences are primitive substitutive sequences.
School uniforms: tradition, benefit or predicament?
Van Aardt, Annette Marie; Wilken, Ilani
2012-01-01
This article focuses on the controversies surrounding school uniforms. Roleplayers in this debate in South Africa are parents, learners and educators, and arguments centre on aspects such as identity, economy and the equalising effect of school uniforms, which are considered in the literature to be benefits. Opposing viewpoints highlight the fact that compulsory uniforms infringe on learners’ constitutional rights to self-expression. The aim of this research was to determine the perspectives ...
Analysis of radial runout for symmetric and asymmetric HDD spindle motors with rotor eccentricity
International Nuclear Information System (INIS)
Kim, T.-J.; Kim, K.-T.; Hwang, S.-M.; Lee, S.-B.; Park, N.-G.
2001-01-01
Radial runout of disk drive spindle is one of the major limiting factors in achieving higher track densities in hard disk drives. Mechanical, magnetic and their coupled origins, such as unbalanced mass, reaction forces and magnetic forces, introduce radial runout of spindle motors. In this paper, radial magnetic forces are calculated with respect to the various rotor eccentricities using analytic method. Based on the results of the radial magnetic forces, the radial runout of the spindle motor is analyzed using finite element and transfer matrices. Results show that an asymmetric motor has a worse performance on unbalanced magnetic forces and radial runout when mechanical and magnetic coupling exists
The radial-hedgehog solution in Landau–de Gennes' theory for nematic liquid crystals
MAJUMDAR, APALA
2011-09-06
We study the radial-hedgehog solution in a three-dimensional spherical droplet, with homeotropic boundary conditions, within the Landau-de Gennes theory for nematic liquid crystals. The radial-hedgehog solution is a candidate for a global Landau-de Gennes minimiser in this model framework and is also a prototype configuration for studying isolated point defects in condensed matter physics. The static properties of the radial-hedgehog solution are governed by a non-linear singular ordinary differential equation. We study the analogies between Ginzburg-Landau vortices and the radial-hedgehog solution and demonstrate a Ginzburg-Landau limit for the Landau-de Gennes theory. We prove that the radial-hedgehog solution is not the global Landau-de Gennes minimiser for droplets of finite radius and sufficiently low temperatures and prove the stability of the radial-hedgehog solution in other parameter regimes. These results contain quantitative information about the effect of geometry and temperature on the properties of the radial-hedgehog solution and the associated biaxial instabilities. © Copyright Cambridge University Press 2011.
The radial-hedgehog solution in Landau–de Gennes' theory for nematic liquid crystals
MAJUMDAR, APALA
2011-01-01
We study the radial-hedgehog solution in a three-dimensional spherical droplet, with homeotropic boundary conditions, within the Landau-de Gennes theory for nematic liquid crystals. The radial-hedgehog solution is a candidate for a global Landau-de Gennes minimiser in this model framework and is also a prototype configuration for studying isolated point defects in condensed matter physics. The static properties of the radial-hedgehog solution are governed by a non-linear singular ordinary differential equation. We study the analogies between Ginzburg-Landau vortices and the radial-hedgehog solution and demonstrate a Ginzburg-Landau limit for the Landau-de Gennes theory. We prove that the radial-hedgehog solution is not the global Landau-de Gennes minimiser for droplets of finite radius and sufficiently low temperatures and prove the stability of the radial-hedgehog solution in other parameter regimes. These results contain quantitative information about the effect of geometry and temperature on the properties of the radial-hedgehog solution and the associated biaxial instabilities. © Copyright Cambridge University Press 2011.
Feng, Yongjiu; Liu, Miaolong; Tong, Xiaohua
2007-06-01
An improved fractal measurement, the weighted radial dimension, is put forward for highway transportation networks distribution. The radial dimension (DL), originated from subway investigation in Stuttgart, is a fractal measurement for transportation systems under ideal assumption considering all the network lines to be homogeneous curves, ignoring the difference on spatial structure, quality and level, especially the highway networks. Considering these defects of radial dimension, an improved fractal measurement called weighted radial dimension (D WL) is introduced and the transportation system in Guangdong province is studied in detail using this novel method. Weighted radial dimensions are measured and calculated, and the spatial structure, intensity and connectivity of transportation networks are discussed in Guangdong province and the four sub-areas: the Pearl River Delta area, the East Costal area, the West Costal area and the Northern Guangdong area. In Guangdong province, the fractal spatial pattern characteristics of transportation system vary remarkably: it is the highest in the Pearl River Delta area, moderate in Costal area and lowest in the Northern Guangdong area. With the Pearl River Delta area as the centre, the weighted radial dimensions decrease with the distance increasing, while the decline level is smaller in the costal area and greater in the Northern Guangdong province. By analysis of the conic of highway density, it is recognized that the density decrease with the distance increasing from the calculation centre (Guangzhou), demonstrating the same trend as weighted radial dimensions shown. Evidently, the improved fractal measurement, weighted radial dimension, is an indictor describing the characteristics of highway transportation system more effectively and accurately.
Radial nerve palsy in mid/distal humeral fractures: is early exploration effective?
Keighley, Geffrey; Hermans, Deborah; Lawton, Vidya; Duckworth, David
2018-03-01
Radial nerve palsies are a common complication with displaced distal humeral fractures. This case series examines the outcomes of early operative exploration and decompression of the nerve with fracture fixation with the view that this provides a solid construct for optimisation of nerve recovery. A total of 10 consecutive patients with a displaced distal humeral fracture and an acute radial nerve palsy were treated by the senior author by open reduction and internal fixation of the distal humerus and exploration and decompression of the radial nerve. Motor function and sensation of the radial nerve was assessed in the post-operative period every 2 months or until full recovery of the radial nerve function had occurred. All patients (100%) had recovery of motor and sensation function of their upper limb in the radial nerve distribution over a 12-month period. Recovery times ranged between 4 and 32 weeks, with the median time to recovery occurring at 26 weeks and the average time to full recovery being 22.9 weeks. Wrist extension recovered by an average of 3 months (range 2-26 weeks) and then finger extension started to recover 2-6 weeks after this. Disability of the arm, shoulder and hand scores ranged from 0 to 11.8 at greater than 1 year post-operatively. Our study demonstrated that early operative exploration of the radial nerve when performing an open stabilization of displaced distal humeral fractures resulted in a 100% recovery of the radial nerve. © 2017 Royal Australasian College of Surgeons.
Observational hints of radial migration in disc galaxies from CALIFA
Ruiz-Lara, T.; Pérez, I.; Florido, E.; Sánchez-Blázquez, P.; Méndez-Abreu, J.; Sánchez-Menguiano, L.; Sánchez, S. F.; Lyubenova, M.; Falcón-Barroso, J.; van de Ven, G.; Marino, R. A.; de Lorenzo-Cáceres, A.; Catalán-Torrecilla, C.; Costantin, L.; Bland-Hawthorn, J.; Galbany, L.; García-Benito, R.; Husemann, B.; Kehrig, C.; Márquez, I.; Mast, D.; Walcher, C. J.; Zibetti, S.; Ziegler, B.; Califa Team
2017-07-01
Context. According to numerical simulations, stars are not always kept at their birth galactocentric distances but they have a tendency to migrate. The importance of this radial migration in shaping galactic light distributions is still unclear. However, if radial migration is indeed important, galaxies with different surface brightness (SB) profiles must display differences in their stellar population properties. Aims: We investigate the role of radial migration in the light distribution and radial stellar content by comparing the inner colour, age, and metallicity gradients for galaxies with different SB profiles. We define these inner parts, avoiding the bulge and bar regions and up to around three disc scale lengths (type I, pure exponential) or the break radius (type II, downbending; type III, upbending). Methods: We analysed 214 spiral galaxies from the CALIFA survey covering different SB profiles. We made use of GASP2D and SDSS data to characterise the light distribution and obtain colour profiles of these spiral galaxies. The stellar age and metallicity profiles were computed using a methodology based on full-spectrum fitting techniques (pPXF, GANDALF, and STECKMAP) to the Integral Field Spectroscopic CALIFA data. Results: The distributions of the colour, stellar age, and stellar metallicity gradients in the inner parts for galaxies displaying different SB profiles are unalike as suggested by Kolmogorov-Smirnov and Anderson-Darling tests. We find a trend in which type II galaxies show the steepest profiles of all, type III show the shallowest, and type I display an intermediate behaviour. Conclusions: These results are consistent with a scenario in which radial migration is more efficient for type III galaxies than for type I systems, where type II galaxies present the lowest radial migration efficiency. In such a scenario, radial migration mixes the stellar content, thereby flattening the radial stellar properties and shaping different SB profiles. However
Instruction sequence based non-uniform complexity classes
Bergstra, J.A.; Middelburg, C.A.
2013-01-01
We present an approach to non-uniform complexity in which single-pass instruction sequences play a key part, and answer various questions that arise from this approach. We introduce several kinds of non-uniform complexity classes. One kind includes a counterpart of the well-known non-uniform
Kimura, T.; Hiraki, Y.; Tao, C.; Tsuchiya, F.; Delamere, P. A.; Yoshioka, K.; Murakami, G.; Yamazaki, A.; Kita, H.; Badman, S. V.; Fukazawa, K.; Yoshikawa, I.; Fujimoto, M.
2018-03-01
The production and transport of plasma mass are essential processes in the dynamics of planetary magnetospheres. At Jupiter, it is hypothesized that Io's volcanic plasma carried out of the plasma torus is transported radially outward in the rotating magnetosphere and is recurrently ejected as plasmoid via tail reconnection. The plasmoid ejection is likely associated with particle energization, radial plasma flow, and transient auroral emissions. However, it has not been demonstrated that plasmoid ejection is sensitive to mass loading because of the lack of simultaneous observations of both processes. We report the response of plasmoid ejection to mass loading during large volcanic eruptions at Io in 2015. Response of the transient aurora to the mass loading rate was investigated based on a combination of Hisaki satellite monitoring and a newly developed analytic model. We found that the transient aurora frequently recurred at a 2-6 day period in response to a mass loading increase from 0.3 to 0.5 t/s. In general, the recurrence of the transient aurora was not significantly correlated with the solar wind, although there was an exceptional event with a maximum emission power of 10 TW after the solar wind shock arrival. The recurrence of plasmoid ejection requires the precondition that an amount comparable to the total mass of magnetosphere, 1.5 Mt, is accumulated in the magnetosphere. A plasmoid mass of more than 0.1 Mt is necessary in case that the plasmoid ejection is the only process for mass release.
Radially global δf computation of neoclassical phenomena in a tokamak pedestal
International Nuclear Information System (INIS)
Landreman, Matt; Parra, Felix I; Catto, Peter J; Ernst, Darin R; Pusztai, Istvan
2014-01-01
Conventional radially-local neoclassical calculations become inadequate if the radial gradient scale lengths of the H-mode pedestal become as small as the poloidal ion gyroradius. Here, we describe a radially global δf continuum code that generalizes neoclassical calculations to allow for stronger gradients. As with conventional neoclassical calculations, the formulation is time-independent and requires only the solution of a single sparse linear system. We demonstrate precise agreement with an asymptotic analytic solution of the radially global kinetic equation in the appropriate limits of aspect ratio and collisionality. This agreement depends crucially on accurate treatment of finite orbit width effects. (paper)
School Uniforms: Esprit de Corps.
Ryan, Rosemary P.; Ryan, Thomas E.
1998-01-01
The benefits of school uniforms far outweigh their short-term costs. School uniforms not only keep students safe, but they increase their self-esteem, promote a more positive attitude toward school, lead to improved student behavior, and help blur social-class distinctions. Students are allowed to wear their own political or religious messages,…
Comments on Beckmann's Uniform Reducts
Cook, Stephen
2006-01-01
Arnold Beckmann defined the uniform reduct of a propositional proof system f to be the set of those bounded arithmetical formulas whose propositional translations have polynomial size f-proofs. We prove that the uniform reduct of f + Extended Frege consists of all true bounded arithmetical formulas iff f + Extended Frege simulates every proof system.
Pellicle transmission uniformity requirements
Brown, Thomas L.; Ito, Kunihiro
1998-12-01
Controlling critical dimensions of devices is a constant battle for the photolithography engineer. Current DUV lithographic process exposure latitude is typically 12 to 15% of the total dose. A third of this exposure latitude budget may be used up by a variable related to masking that has not previously received much attention. The emphasis on pellicle transmission has been focused on increasing the average transmission. Much less, attention has been paid to transmission uniformity. This paper explores the total demand on the photospeed latitude budget, the causes of pellicle transmission nonuniformity and examines reasonable expectations for pellicle performance. Modeling is used to examine how the two primary errors in pellicle manufacturing contribute to nonuniformity in transmission. World-class pellicle transmission uniformity standards are discussed and a comparison made between specifications of other components in the photolithographic process. Specifications for other materials or parameters are used as benchmarks to develop a proposed industry standard for pellicle transmission uniformity.
Directory of Open Access Journals (Sweden)
Mohammadjavad Hosseini
2017-07-01
Full Text Available A high-performance centrifugal compressor is needed for numerous industry applications nowadays. The radial gap ratio between the impeller and the diffuser vanes plays an important role in the improvement of the compressor performance. In this paper, the effects of the radial gap ratio on a high-pressure ratio centrifugal compressor are investigated using numerical simulations. The performance and the flow field are compared for six different radial gap ratios and five rotational speeds. The minimal radial gap ratio was 1.04 and the maximal was 1.14. Results showed that reducing the radial gap ratio decreases the choke mass flow rate. For the tip-speed Mach number (impeller inlet with Mu < 1, the pressure recovery and the loss coefficients are not sensitive to the radial gap ratio. However, for Mu ≥ 1, the best radial gap ratio is 1.08 for the pressure recovery and the loss coefficients. Furthermore, the impeller pressure ratio and efficiency are reduced by increasing the radial gap ratio. Finally, the compressor efficiency was compared for different radial gap ratios. For Mu < 1, the radial gap ratio does not have noticeable effects. In comparison, the radial gap ratio of 1.08 has the best performance for Mu ≥ 1.
Downsampling Non-Uniformly Sampled Data
Directory of Open Access Journals (Sweden)
Fredrik Gustafsson
2007-10-01
Full Text Available Decimating a uniformly sampled signal a factor D involves low-pass antialias filtering with normalized cutoff frequency 1/D followed by picking out every Dth sample. Alternatively, decimation can be done in the frequency domain using the fast Fourier transform (FFT algorithm, after zero-padding the signal and truncating the FFT. We outline three approaches to decimate non-uniformly sampled signals, which are all based on interpolation. The interpolation is done in different domains, and the inter-sample behavior does not need to be known. The first one interpolates the signal to a uniformly sampling, after which standard decimation can be applied. The second one interpolates a continuous-time convolution integral, that implements the antialias filter, after which every Dth sample can be picked out. The third frequency domain approach computes an approximate Fourier transform, after which truncation and IFFT give the desired result. Simulations indicate that the second approach is particularly useful. A thorough analysis is therefore performed for this case, using the assumption that the non-uniformly distributed sampling instants are generated by a stochastic process.
Propagation of a radial phased-locked Lorentz beam array in turbulent atmosphere.
Zhou, Guoquan
2011-11-21
A radial phased-locked (PL) Lorentz beam array provides an appropriate theoretical model to describe a coherent diode laser array, which is an efficient radiation source for high-power beaming use. The propagation of a radial PL Lorentz beam array in turbulent atmosphere is investigated. Based on the extended Huygens-Fresnel integral and some mathematical techniques, analytical formulae for the average intensity and the effective beam size of a radial PL Lorentz beam array are derived in turbulent atmosphere. The average intensity distribution and the spreading properties of a radial PL Lorentz beam array in turbulent atmosphere are numerically calculated. The influences of the beam parameters and the structure constant of the atmospheric turbulence on the propagation of a radial PL Lorentz beam array in turbulent atmosphere are discussed in detail. © 2011 Optical Society of America
Study on the radial vibration and acoustic field of an isotropic circular ring radiator.
Lin, Shuyu; Xu, Long
2012-01-01
Based on the exact analytical theory, the radial vibration of an isotropic circular ring is studied and its electro-mechanical equivalent circuit is obtained. By means of the equivalent circuit model, the resonance frequency equation is derived; the relationship between the radial resonance frequency, the radial displacement amplitude magnification and the geometrical dimensions, the material property is analyzed. For comparison, numerical method is used to simulate the radial vibration of isotropic circular rings. The resonance frequency and the radial vibrational displacement distribution are obtained, and the radial radiation acoustic field of the circular ring in radial vibration is simulated. It is illustrated that the radial resonance frequencies from the analytical method and the numerical method are in good agreement when the height is much less than the radius. When the height becomes large relative to the radius, the frequency deviation from the two methods becomes large. The reason is that the exact analytical theory is limited to thin circular ring whose height must be much less than its radius. Copyright © 2011 Elsevier B.V. All rights reserved.
Surface interpolation with radial basis functions for medical imaging
International Nuclear Information System (INIS)
Carr, J.C.; Beatson, R.K.; Fright, W.R.
1997-01-01
Radial basis functions are presented as a practical solution to the problem of interpolating incomplete surfaces derived from three-dimensional (3-D) medical graphics. The specific application considered is the design of cranial implants for the repair of defects, usually holes, in the skull. Radial basis functions impose few restrictions on the geometry of the interpolation centers and are suited to problems where interpolation centers do not form a regular grid. However, their high computational requirements have previously limited their use to problems where the number of interpolation centers is small (<300). Recently developed fast evaluation techniques have overcome these limitations and made radial basis interpolation a practical approach for larger data sets. In this paper radial basis functions are fitted to depth-maps of the skull's surface, obtained from X-ray computed tomography (CT) data using ray-tracing techniques. They are used to smoothly interpolate the surface of the skull across defect regions. The resulting mathematical description of the skull's surface can be evaluated at any desired resolution to be rendered on a graphics workstation or to generate instructions for operating a computer numerically controlled (CNC) mill
An axially averaged-radial transport model of tokamak edge plasmas
International Nuclear Information System (INIS)
Prinja, A.K.; Conn, R.W.
1984-01-01
A two-zone axially averaged-radial transport model for edge plasmas is described that incorporates parallel electron and ion conduction, localized recycling, parallel electron pressure gradient effects and sheath losses. Results for high recycling show that the radial electron temperature profile is determined by parallel electron conduction over short radial distances (proportional 3 cm). At larger radius where Tsub(e) has fallen appreciably, convective transport becomes equally important. The downstream density and ion temperature profiles are very flat over the region where electron conduction dominates. This is seen to result from a sharply decaying velocity profile that follows the radial electron temperature. A one-dimensional analytical recycling model shows that at high neutral pumping rates, the plasma density at the plate, nsub(ia), scales linearly with the unperturbed background density, nsub(io). When ionization dominates nsub(ia)/nsub(io) proportional exp(nsub(io)) while in the intermediate regime nsub(ia)/nsub(io) proportional exp(proportional nsub(io)). Such behavior is qualitatively in accord with experimental observations. (orig.)
Weak completeness of the Bourbaki quasi-uniformity
Directory of Open Access Journals (Sweden)
M.A. Sánchez Granero
2001-04-01
Full Text Available The concept of semicompleteness (weaker than half-completeness is defined for the Bourbaki quasi-uniformity of the hyperspace of a quasi-uniform space. It is proved that the Bourbaki quasi-uniformity is semicomplete in the space of nonempty sets of a quasi-uniform space (X,U if and only if each stable filter on (X,U* has a cluster point in (X,U. As a consequence the space of nonempty sets of a quasi-pseudometric space is semicomplete if and only if the space itself is half-complete. It is also given a characterization of semicompleteness of the space of nonempty U*-compact sets of a quasi-uniform space (X,U which extends the well known Zenor-Morita theorem.
Linear radial pulsation theory. Lecture 5
International Nuclear Information System (INIS)
Cox, A.N.
1983-01-01
We describe a method for getting an equilibrium stellar envelope model using as input the total mass, the envelope mass, the surface effective temperature, the total surface luminosity, and the composition of the envelope. Then wih the structure of the envelope model known, we present a method for obtaining the raidal pulsation periods and growth rates for low order modes. The large amplitude pulsations observed for the yellow and red giants and supergiants are always these radial models, but for the stars nearer the main sequence, as for all of our stars and for the white dwarfs, there frequently are nonradial modes occuring also. Application of linear theory radial pulsation theory is made to the giant star sigma Scuti variables, while the linear nonradial theory will be used for the B stars in later lectures
Distribution profiling of a transverse load using the DGD spectrum of chirped FBGs.
Descamps, Frédéric; Caucheteur, Christophe; Mégret, Patrice; Bette, Sébastien
2015-07-13
In this paper, we propose a new method to determine the longitudinal distribution of a non-uniform transverse force applied to an optical fiber. For that purpose, we use a chirped fiber Bragg grating (CFBG) for which we monitor the polarization parameters in reflection. In particular, we demonstrate that the differential group delay (DGD) spectrum of the CFBG is an imprint of the load profile so that it can be used for the shape determination of an applied load. Thereafter, we discuss the influence of the CFBG parameters on the achievable accuracy and resolution of our technique. An experimental validation is finally reported with two 48 mm long CFBGs subject to step transverse load profiles.
Análisis de sistemas de distribución radiales bajo condiciones de polución armónica
Directory of Open Access Journals (Sweden)
Ramón Alfonso Gallego Rendón
2005-11-01
Full Text Available Los sistemas de distribución presentan un alto contenido de armónicos debido a la presencia de cargas no lineales tales como equipos electrónicos y elementos ferromagnéticos en saturación. El análisis de este tipo de sistemas es el objetivo del flujo de carga armónico. En este artículo se muestra una metodología de flujo de carga armónico adaptado a los sistemas de distribución dadas las particularidades propias de estos sistemas como es la topología radial. Igualmente se muestra una implementación computacional desarrollada bajo el esquema de programación orientada a objetos usando el sistema operativo Windows. Se presentan ejemplos de prueba IEEE. / Distribution systems can present a high harmonic level due to existence of non linear loads such as electronic equipment. The analysis of these systems is the objective of harmonic load flow. This document shows a new methodology of harmonic load flow which considers the distribution systems characteristics. Likewise it shows an object oriented software developed in Windows. IEEE test systems are presented.
Directory of Open Access Journals (Sweden)
Adnan M.F.
2017-01-01
Full Text Available Non-uniform thickness section section is considered one of the most effective approaches to reduce automotive part weight. Reduction in term of mass and size result in less fuel consumption and greenhouse gases. Thickness is the most significant parameter to formability, therefore forming a section with non-uniform thickness becomes a great challenge. Improper process and incorrect decision may lead to severe defect and one of the main concerns is the springback. This study will focus on springback behaviour of non-uniform thickness AA6061 strip with complex profile using Taguchi Method. Profile projector (PC 3000 is used to measure the spring back and two-line technique is applied to measure angles (after loading between two lines. Three parameters (i.e. annealing temperature, thickness ratio and bend angle are studied, and results determine that the most significant parameter is bend angle, followed by thickness ratio, and then by the annealing temperature of the specimen during bending process.
Optimization of a radially cooled pebble bed reactor - HTR2008-58117
International Nuclear Information System (INIS)
Boer, B.; Kloosterman, J. L.; Lathouwers, D.; Van Der Hagen, T. H. J. J.; Van Dam, H.
2008-01-01
By altering the coolant flow direction in a pebble bed reactor from axial to radial, the pressure drop can be reduced tremendously. In this case the coolant flows from the outer reflector through the pebble bed and finally to flow paths in the inner reflector. As a consequence, the fuel temperatures are elevated due to the reduced heat transfer of the coolant. However, the power profile and pebble size in a radially cooled pebble bed reactor can be optimized to achieve lower fuel temperatures than current axially cooled designs, while the low pressure drop can be maintained. The radial power profile in the core can be altered by adopting multi-pass fuel management using several radial fuel zones in the core. The optimal power profile yielding a flat temperature profile is derived analytically and is approximated by radial fuel zoning. In this case, the pebbles pass through the outer region of the core first and each consecutive pass is located in a fuel zone closer to the inner reflector. Thereby, the resulting radial distribution of the fissile material in the core is influenced and the temperature profile is close to optimal. The fuel temperature in the pebbles can be further reduced by reducing the standard pebble diameter from 6 cm to a value as low as I cm. An analytical investigation is used to demonstrate the effects on the fuel temperature and pressure drop for both radial and axial cooling. Finally, two-dimensional numerical calculations were performed, using codes for neutronics, thermal-hydraulics and fuel depletion analysis, in order to validate the results for the optimized design that were obtained from the analytical investigations. It was found that for a radially cooled design with an optimized power profile and reduced pebble diameter (below 3.5 cm) both a reduction in the pressure drop (Δp = -2.6 bar), which increases the reactor efficiency with several percent, and a reduction in the maximum fuel temperature (ΔT = -50 deg. C) can be achieved
Radiographic study of distal radial physeal closure in thoroughbred horses
International Nuclear Information System (INIS)
Vulcano, L.C.; Mamprim, M.J.; Muniz, L.M.R.; Moreira, A.F.; Luna, S.P.L.
1997-01-01
Monthly radiography was performed to study distal radial physeal closure in ten male and ten female Throughbred horses. The height, thoracic circumference and metacarpus circumference were also measured, Distal radial physeal closure time was sooner in females than males, and took 701 +/- 37 and 748 +/- 55 days respectively
On Prolonging Network Lifetime through Load-Similar Node Deployment in Wireless Sensor Networks
Li, Qiao-Qin; Gong, Haigang; Liu, Ming; Yang, Mei; Zheng, Jun
2011-01-01
This paper is focused on the study of the energy hole problem in the Progressive Multi-hop Rotational Clustered (PMRC)-structure, a highly scalable wireless sensor network (WSN) architecture. Based on an analysis on the traffic load distribution in PMRC-based WSNs, we propose a novel load-similar node distribution strategy combined with the Minimum Overlapping Layers (MOL) scheme to address the energy hole problem in PMRC-based WSNs. In this strategy, sensor nodes are deployed in the network area according to the load distribution. That is, more nodes shall be deployed in the range where the average load is higher, and then the loads among different areas in the sensor network tend to be balanced. Simulation results demonstrate that the load-similar node distribution strategy prolongs network lifetime and reduces the average packet latency in comparison with existing nonuniform node distribution and uniform node distribution strategies. Note that, besides the PMRC structure, the analysis model and the proposed load-similar node distribution strategy are also applicable to other multi-hop WSN structures. PMID:22163809
Swozzle based burner tube premixer including inlet air conditioner for low emissions combustion
Tuthill, Richard Sterling; Bechtel, II, William Theodore; Benoit, Jeffrey Arthur; Black, Stephen Hugh; Bland, Robert James; DeLeonardo, Guy Wayne; Meyer, Stefan Martin; Taura, Joseph Charles; Battaglioli, John Luigi
2002-01-01
A burner for use in a combustion system of a heavy-duty industrial gas turbine includes a fuel/air premixer having an air inlet, a fuel inlet, and an annular mixing passage. The fuel/air premixer mixes fuel and air into a uniform mixture for injection into a combustor reaction zone. The burner also includes an inlet flow conditioner disposed at the air inlet of the fuel/air premixer for controlling a radial and circumferential distribution of incoming air. The pattern of perforations in the inlet flow conditioner is designed such that a uniform air flow distribution is produced at the swirler inlet annulus in both the radial and circumference directions. The premixer includes a swozzle assembly having a series of preferably air foil shaped turning vanes that impart swirl to the airflow entering via the inlet flow conditioner. Each air foil contains internal fuel flow passages that introduce natural gas fuel into the air stream via fuel metering holes that pass through the walls of the air foil shaped turning vanes. By injecting fuel in this manner, an aerodynamically clean flow field is maintained throughout the premixer. By injecting fuel via two separate passages, the fuel/air mixture strength distribution can be controlled in the radial direction to obtain optimum radial concentration profiles for control of emissions, lean blow outs, and combustion driven dynamic pressure activity as machine and combustor load are varied.
Suwannoi, Panita; Chomnawang, Mullika; Sarisuta, Narong; Reichl, Stephan; Müller-Goymann, Christel C
2017-12-01
The aim of the present study was to develop acyclovir (ACV) ocular drug delivery systems of bovine serum albumin (BSA) nanoparticles as well as to assess their in vitro transcorneal permeation across human corneal epithelial (HCE-T) cell multilayers. The ACV-loaded BSA nanoparticles were prepared by desolvation method along with physicochemical characterization, cytotoxicity, as well as in vitro transcorneal permeation studies across HCE-T cell multilayers. The nanoparticles appeared to be spherical in shape and nearly uniform in size of about 200 nm. The size of nanoparticles became smaller with decreasing BSA concentration, while the ratios of water to ethanol seemed not to affect the size. Increasing the amount of ethanol in desolvation process led to significant reduction of drug entrapment of nanoparticles with smaller size and more uniformity. The ACV-loaded BSA nanoparticles prepared were shown to have no cytotoxic effect on HCE-T cells used in permeation studies. The in vitro transcorneal permeation results revealed that ACV could permeate through the HCE-T cell multilayers significantly higher from BSA nanoparticles than from aqueous ACV solutions. The ACV-loaded BSA nanoparticles could be prepared by desolvation method without glutaraldehyde in the formulation. ACV could increasingly permeate through the multilayers of HCE-T cells from the ACV-loaded BSA nanoparticles. Therefore, the ACV-loaded BSA nanoparticles could be a highly potential ocular drug delivery system.
Effects of relativistic small radial component on atomic photoionization cross sections
International Nuclear Information System (INIS)
Liu Xiaobin; Xing Yongzhong; Sun Xiaowei
2008-01-01
The effects of relativistic small radial component on atomic photoionization cross sections have been studied within relativistic average self-consistent field theory. Relativistic effects are relatively unimportant for low photon energy, along with a review of high-energy photoionization the relativistic effects are quite important. The effects of relativistic small radial component on photoionization process should show breakdown when the nuclear finite-size effects is taken into account. The compression of wavefunction into the space near nucleus is so strong in highly charged ions that the electronic radius greatly decreases, and the effects of relativistic small radial component on photoionization cross sections turn to stronger than ordinary atoms. Since relativistic effects are extremely sensitive to the behavior of small radial component, the results are in good agreement with relativistic effects on photoionization cross section. (authors)
Bessel-like beams modulated by arbitrary radial functions
Herman; Wiggins
2000-06-01
An approximate method for determining the radial and axial intensity of a Bessel-like beam is presented for the general case in which a radial Bessel distribution of any order is modulated by an arbitrary function. For Bessel-Gauss, generalized Bessel-Gauss, and Bessel-super-Gauss beams, this simple approximation yields results that are very close to the exact values, while they are exact for Bessel beams. A practical beam that can be generated with a combination of simple lenses is also analyzed and illustrated.
Bilateral radial neck fractures – A Case Report
Directory of Open Access Journals (Sweden)
ABY Ng
2007-11-01
Full Text Available Radial head and neck fractures are the most frequently seen elbow fractures. The usual cause of this injury is a fall onto an outstretched hand with a partly flexed elbow. We report here an unusual case of bilateral non-displaced radial neck fractures in a patient who presented with complaints of pain in both elbows following a simple fall. This case highlights the need for a high index of suspicion in the diagnosis of multiple injuries, no matter how `trivial` the mechanism of injury.
46 CFR 310.63 - Uniforms and textbooks.
2010-10-01
... 46 Shipping 8 2010-10-01 2010-10-01 false Uniforms and textbooks. 310.63 Section 310.63 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION TRAINING MERCHANT MARINE TRAINING Admission and Training of Midshipmen at the United States Merchant Marine Academy § 310.63 Uniforms and textbooks. The Academy shall supply midshipmen uniforms an...
Energy Technology Data Exchange (ETDEWEB)
Blue, C.A.; Sikka, V.K. [Oak Ridge National Lab., TN (United States); Chun, Jung-Hoon [Massachusetts Institute of Technology, Cambridge, MA (United States); Ando, T. [Tufts Univ., Medford, MA (United States)
1997-04-01
The uniform-droplet process is a new method of liquid-metal atomization that results in single droplets that can be used to produce mono-size powders or sprayed-on to substrates to produce near-net shapes with tailored microstructure. The mono-sized powder-production capability of the uniform-droplet process also has the potential of permitting engineered powder blends to produce components of controlled porosity. Metal and alloy powders are commercially produced by at least three different methods: gas atomization, water atomization, and rotating disk. All three methods produce powders of a broad range in size with a very small yield of fine powders with single-sized droplets that can be used to produce mono-size powders or sprayed-on substrates to produce near-net shapes with tailored microstructures. The economical analysis has shown the process to have the potential of reducing capital cost by 50% and operating cost by 37.5% when applied to powder making. For the spray-forming process, a 25% savings is expected in both the capital and operating costs. The project is jointly carried out at Massachusetts Institute of Technology (MIT), Tuffs University, and Oak Ridge National Laboratory (ORNL). Preliminary interactions with both finished parts and powder producers have shown a strong interest in the uniform-droplet process. Systematic studies are being conducted to optimize the process parameters, understand the solidification of droplets and spray deposits, and develop a uniform-droplet-system (UDS) apparatus appropriate for processing engineering alloys.
Energy Technology Data Exchange (ETDEWEB)
Sahoo, N.C. [Faculty of Engineering and Technology, Multimedia University, Jalan Ayer Keroh Lama, Bukit Beruang, 75450 Melaka (Malaysia); Prasad, K. [Faculty of Information Science and Technology, Multimedia University, Jalan Ayer Keroh Lama, Bukit Beruang, 75450 Melaka (Malaysia)
2006-11-15
This paper presents a fuzzy genetic approach for reconfiguration of radial distribution systems (RDS) so as to maximize the voltage stability of the network for a specific set of loads. The network reconfiguration involves a mechanism for selection of the best set of branches to be opened, one from each loop, such that the reconfigured RDS possesses desired performance characteristics. This discrete solution space is better handled by the proposed scheme, which maximizes a suitable optimizing function (computed using two different approaches). In the first approach, this function is chosen as the average of a voltage stability index of all the buses in the RDS, while in the second approach, the complete RDS is reduced to a two bus equivalent system and the optimizing function is the voltage stability index of this reduced two bus system. The fuzzy genetic algorithm uses a suitable coding and decoding scheme for maintaining the radial nature of the network at every stage of genetic evolution, and it also uses a fuzzy rule based mutation controller for efficient search of the solution space. This method, tested on 69 bus and 33 bus RDSs, shows promising results for the both approaches. It is also observed that the network losses are reduced when the voltage stability is enhanced by the network reconfiguration. (author)
WHEELSET AXLE WITH THE CAVITY OF UNIFORM CROSS SECTION
Directory of Open Access Journals (Sweden)
S. R. Kolesnykov
2014-10-01
Full Text Available Purpose. Due to operation in complex loading conditions, the rolling stock wheelsets should provide high reliability, since the train traffic safety largely depends on them. Design and technical condition of wheelsets affect the smoothness, intensity of forces generated by the interaction between the car and track, and the motion resistance. Specificity of the axle operation consists in the fact that it undergoes the bending stresses under loading. These stresses are unevenly distributed along the cross-sectional area, reaching the highest values in the outer fibers and the minimal values in the internal ones. This aspect sets the problem of replacement of the uniform cross section with the hollow cross section. The disadvantages of hollow axle design, which are used at the present time, should include a significant manufacturing complexity of the variable section cavity. The purpose is to develop a modernized design of the wheelset axle. Methodology. A construction of the hollow axle having an inner longitudinal cylindrical through hole of the constant diameter throughout its length was proposed. The item is made of steel seamless tube. The inner surface of the tube is treated by mechanical means to remove the voltage concentrations in the internal longitudinal cylindrical through hole, which has a constant diameter along the entire length of the axle. Findings. Application of this design will facilitate manufacturing of the hollow axle and the machining of the inner longitudinal through hole, while retaining all the use advantages of the hollow axle in the rolling stock wheel pairs. Another use advantage of the hollow axle of this design is the absence of partial heterogeneity of the metal, which is inevitably, occurs during the solid axles blanking. Originality. A new design of the wheelset hollow axle of railway rolling stock was proposed. Practical value. Introduction of the new design simplifying the manufacture and mechanical treatment of
A Secured Load Mitigation and Distribution Scheme for Securing SIP Server
Directory of Open Access Journals (Sweden)
Vennila Ganesan
2017-01-01
Full Text Available Managing the performance of the Session Initiation Protocol (SIP server under heavy load conditions is a critical task in a Voice over Internet Protocol (VoIP network. In this paper, a two-tier model is proposed for the security, load mitigation, and distribution issues of the SIP server. In the first tier, the proposed handler segregates and drops the malicious traffic. The second tier provides a uniform load of distribution, using the least session termination time (LSTT algorithm. Besides, the mean session termination time is minimized by reducing the waiting time of the SIP messages. Efficiency of the LSTT algorithm is evaluated through the experimental test bed by considering with and without a handler. The experimental results establish that the proposed two-tier model improves the throughput and the CPU utilization. It also reduces the response time and error rate while preserving the quality of multimedia session delivery. This two-tier model provides robust security, dynamic load distribution, appropriate server selection, and session synchronization.
Ultimate design load analysis of planetary gearbox bearings under extreme events
DEFF Research Database (Denmark)
Gallego Calderon, Juan Felipe; Natarajan, Anand; Cutululis, Nicolaos Antonio
2017-01-01
This paper investigates the impact of extreme events on the planet bearings of a 5 MW gearbox. The system is simulated using an aeroelastic tool, where the turbine structure is modeled, and MATLAB/Simulink, where the drivetrain (gearbox and generator) are modeled using a lumped-parameter approach....... Three extreme events are assessed: low-voltage ride through, emergency stop and normal stop. The analysis is focused on finding which event has the most negative impact on the bearing extreme radial loads. The two latter events are carried out following the guidelines of the International...
Radial Color Gradient in a Globular Cluster 1. M68
Directory of Open Access Journals (Sweden)
Sukyoung Yi
1990-12-01
Full Text Available Stars in M68 from the observed color-magnitude diagrams with CCD were integrated to find any radial gradient. The result shows that M68 has a slightly bluer core. The main cause of these calculated radial color variations seems to come from the random distribution of giants.
Low reflectance radio frequency load
Ives, R. Lawrence; Mizuhara, Yosuke M
2014-04-01
A load for traveling microwave energy has an absorptive volume defined by cylindrical body enclosed by a first end cap and a second end cap. The first end cap has an aperture for the passage of an input waveguide with a rotating part that is coupled to a reflective mirror. The inner surfaces of the absorptive volume consist of a resistive material or are coated with a coating which absorbs a fraction of incident RF energy, and the remainder of the RF energy reflects. The angle of the reflector and end caps is selected such that reflected RF energy dissipates an increasing percentage of the remaining RF energy at each reflection, and the reflected RF energy which returns to the rotating mirror is directed to the back surface of the rotating reflector, and is not coupled to the input waveguide. Additionally, the reflector may have a surface which generates a more uniform power distribution function axially and laterally, to increase the power handling capability of the RF load. The input waveguide may be corrugated for HE11 mode input energy.
Uniform Single Valued Neutrosophic Graphs
Directory of Open Access Journals (Sweden)
S. Broumi
2017-09-01
Full Text Available In this paper, we propose a new concept named the uniform single valued neutrosophic graph. An illustrative example and some properties are examined. Next, we develop an algorithmic approach for computing the complement of the single valued neutrosophic graph. A numerical example is demonstrated for computing the complement of single valued neutrosophic graphs and uniform single valued neutrosophic graph.
Uniform-related infection control practices of dental students
Directory of Open Access Journals (Sweden)
Aljohani Y
2017-04-01
Full Text Available Yazan Aljohani,1 Mohammed Almutadares,1 Khalid Alfaifi,1 Mona El Madhoun,1 Maysoon H Albahiti,2 Nadia Al-Hazmi3 1Internship Program, Faculty of dentistry, King Abdulaziz University, 2Department of Endodontics, King Abdulaziz University, 3Department of Oral Biology, King Abdulaziz University, Faculty of Dentistry, Jeddah, Saudi Arabia Background: Uniform-related infection control practices are sometimes overlooked and underemphasized. In Saudi Arabia, personal protective equipment must meet global standards for infection control, but the country’s Islamic legislature also needs to be taken into account. Aim: To assess uniform-related infection control practices of a group of dental students in a dental school in Saudi Arabia and compare the results with existing literature related to cross-contamination through uniforms in the dental field. Method: A questionnaire was formulated and distributed to dental students at King Abdulaziz University Faculty of Dentistry in Jeddah, Saudi Arabia, which queried the students about their uniform-related infection control practices and their methods and frequency of laundering and sanitizing their uniforms, footwear, and name tags. Results: There is a significant difference between genders with regard to daily uniform habits. The frequency of uniform washing was below the standard and almost 30% of students were not aware of how their uniforms are washed. Added to this, there is no consensus on a unified uniform for male and female students. Conclusion: Information on preventing cross-contamination through wearing uniforms must be supplied, reinforced, and emphasized while taking into consideration the cultural needs of the Saudi society. Keywords: cross-contamination, infection control, dental students, uniforms
Apparatus for feeding nuclear fuel pellets to a loading tray
International Nuclear Information System (INIS)
Huggins, T.B.
1979-01-01
Apparatus for feeding nuclear fuel pellets at a uniform predetermined rate between pellet centering and grinding apparatus and a tray for loading pellets into nuclear fuel rod. Pellets discharged from the grinding apparatus are conveyed by a belt to a drive wheel forcing the pellets in engagement with the belt. The pellets under the drive wheel are capable of pushing a line of about 36 pellets onto a pellet dumping mechanism. As the dumping mechanism is actuated to dump the pellets on to a loading tray, the pellets moving toward the mechanism are stopped and the drive wheel is simultaneously lifted off the pellets until the pellet dumping process is completed. (U.K.)
Plastic collapse of tubes submitted to a ring load by optimization
International Nuclear Information System (INIS)
Zouain, N.
1982-05-01
The limit analysis of a tube with finite lenght, made of a rigid - plastic material, is considered for the case of an internal load uniformely distributed in a cross section of the tube. The exact creep law is calculated for several qualitatively differents cases, namely different tube lenghts. The corresponding stress and collapse mechanisms are given so that they can be compared to the approximations developed here. The static and kinematic theorems on plastic collapse are used for establishing two numerical methods of resolution, specifically mathematical programming and finite element method. These mathematical methods are applied to collapse load for the considered tube. (E.G.) [pt
Stress distribution in a semi-infinite body symmetrically loaded over a circular area
Mcginness, H.
1980-01-01
Algorithms are developed for computing stresses in a semi-infinite body when loaded by a uniform pressure acting over a circular area. The algorithm allows easy determination of any stress component in a semi-infinite body having a known Poisson's ratio. Example curves are plotted for Portland cement grout and metal representative values.