Bending Tolerance Research Articles

Magnetic Field Design of Combined-function Magnets Wound with Coated Conductors

For accelerator magnets, high Tc superconductors (HTS) are a remarkable option comparing with low Tc superconductors (LTS), since they possess several distinctive characteristics, such as good thermal stability and high cooling efficiency. On the other side, HTSs have strong mechanical constraints which make them hard to shape, like bending and winding. In this paper, a method is proposed to solve the mechanical constraint problems of HTSs, and the feasibility of applying HTSs to combined-function accelerator magnets is proved. The detailed method is presented to apply coated conductors into the design of a combined function accelerator magnet containing both dipole and quadrupole magnetic field components, which is named 2+4 pole magnet in this paper. This method takes electromagnetic characteristics of coated conductors into account, and it is capable of solving their mechanical constraint problems. First a 2D cross-sectional design of the straight section was completed, with a layout in the form of multi-layers to generate required magnetic fields. Then a 3D design was carried out to wind coil ends considering flat-wise/edge- wise bending and torsion tolerance. The locations and angles of coated conductors were optimized to improve the efficiency of field generation and minimize the field error. Results show that coil ends can be successfully designed, and electromagnetic analyses show that the designed magnet can properly generate required magnetic field.

15-1 極薄フィルム上に形成した酸化物半導体TFTの湾曲評価(第15部門情報ディスプレイ)

15-1 極薄フィルム上に形成した酸化物半導体TFTの湾曲評価(第15部門情報ディスプレイ)

Characteristics of a-IGZO/ITO Hybrid Layer Deposited by Magnetron Sputtering

Transparent a-IGZO (In-Ga-Zn-O) films have been actively studied for use in the fabrication of high-quality TFTs. In this study, a-IGZO films and a-IGZO/ITO double layers were deposited by DC magnetron sputtering under various oxygen flow rates. The a-IGZO films showed an amorphous structure up to 500 degrees C. The deposition rate of these films decreased with an increase in the amount of oxygen gas. The amount of indium atoms in the film was confirmed to be 11.4% higher than the target. The resistivity of double layer follows the rules for parallel DC circuits The maximum Hall mobility of the a-IGZO/ITO double layers was found to be 37.42 cm2/V x N s. The electrical properties of the double layers were strongly dependent on their thickness ratio. The IGZO/ITO double layer was subjected to compressive stress, while the ITO/IGZO double layer was subjected to tensile stress. The bending tolerance was found to depend on the a-IGZO thickness.

Injury tolerance of tibia for the car–pedestrian impact

Lower limbs are normally the first contacted body region during car–pedestrian accidents, and easily suffer serious injuries. The previous tibia bending tolerances for pedestrian safety were mainly developed from three-point bending tests on tibia mid-shaft. The tibia tolerances of other locations are still not investigated enough. In addition, tibia loading condition under the car–pedestrian impact should be explored to compare with the three-point bending. This work aims to investigate the injury tolerance of tibia fracture with combined experimental data and numerical simulation. Eleven new reported quasi-static bending tests of tibia mid-shaft, and additional eleven dynamic mid-shaft bending test results in the previous literature were used to define injury risk functions. Furthermore, to investigate the influence of tibia locations on bending tolerance, finite element simulations with lower limb model were implemented according to three-point bending and pedestrian impact conditions. The regressive curve of tibia bending tolerance was obtained from the simulations on the different impact locations, and indicated that tibia fracture tolerance could vary largely due to the impact locations for the car–pedestrian crash.

Bending strain analysis considering a shift of the neutral axis for YBCO coated conductorswith and without a Cu stabilizing layer

Bending tolerance is one of the most fundamental mechanical propertiesof YBCO coated conductors for application to a superconductingcoil. In order to reveal the origin of the difference in critical current (Ic) with bending radius among various conductors, it is essential to estimate the bendingstrain at a superconducting layer. In this study, the bending strain was evaluated bothexperimentally and analytically for YBCO coated conductors with and without a Custabilizing layer. The internal tensile and bending strain of YBCO film in a compositeconductor was directly evaluated from the shift of the Bragg peaks of a YBCO film usingsynchrotron radiation. We also present an analytical method to calculate the neutral axisposition by considering its shift due to the progress of plastic deformation of thecomponents such as Cu, Ag and Hastelloy. The validity of our strain analysis wasconfirmed by agreement of the measured and calculated internal bending strains. Thecalculation result shows that yielding of the Cu stabilizing layer has a stronginfluence on the position of the neutral axis and results in a weaker dependence ofIc. A comparison with tensile strain measurements shows that the effect of bending can bepredicted from the tensile strain dependence.

Flexible Dye-Sensitized Solar Cell Based on Vertical ZnO Nanowire Arrays.

Flexible dye-sensitized solar cells are fabricated using vertically aligned ZnO nanowire arrays that are transferred onto ITO-coated poly(ethylene terephthalate) substrates using a simple peel-off process. The solar cells demonstrate an energy conversion efficiency of 0.44% with good bending tolerance. This technique paves a new route for building large-scale cost-effective flexible photovoltaic and optoelectronic devices.

An Exploration of Maitland's Concept of Pain Irritability in Patients with Low Back Pain

Maitland's construct of musculoskeletal pain irritability is widely used by physical therapists for making decisions about the vigor of examination and treatment, but this construct has not been defined to the extent that its measurement properties can be tested. The purposes of this study were to 1) determine if physical therapists utilize low back pain (LBP) irritability judgments to make treatment decisions, 2) identify LBP characteristics appropriate for an LBP irritability construct, and 3) develop a measurement construct of LBP irritability. Physical therapists evaluated and treated 183 subjects with LBP. The therapists judged the subjects' LBP as irritable or non-irritable, and recorded treatments provided at the initial visit. A principal-components analysis (PCA) was performed on 14 patient-reported LBP characteristics to identify potential components of a measurement construct of LBP irritability. The therapists' irritability judgments were found to be associated with the types of treatments prescribed. Five dimensions of LBP irritability were identified by the PCA from the 14 LBP characteristics considered. Four of these dimensions were associated with the therapists' LBP irritability judgments. The Roland-Morris Disability Questionnaire, presence of distal symptoms, and forward bending tolerance were found to have a stronger association with the irritability judgments than the dimensions of irritability identified in this study. Validated measures of LBP characteristics in current clinical use may adequately capture Maitland's concept of irritability.

Ｆｅ‐Ｇａ合金（Ｇａｌｆｅｎｏｌ）と非磁性材料の積層型ユニモルフアクチュエータ

We investigate a bending actuator based on unimorph, lamination of Galfenol (Iron-gallium alloy) and non-magnetic material. The Galfenol U-shape yoke bonded with stainless plates (lamination) is wound coils, and iscomposed close magnetic loop with connected an iron plate. The magnetostriction in longitude direction is constrained by the stainless, thus, the lamination yields bending deformation with the current induced. The advantage of the actuator is simple, compact and ease of assembling including winding coil, and high tolerance against bending, tensileand impact. We machined the yoke from a plate of 1mm thickness of Galfenol of Research grade using ultra highprecision cutting technique. The prototype with lamination thickness of 1mm was observed the displacement 13 μm and 1st resonance 1.6 kHz, and the high bending (tensile) tolerance withstanding suspended weight of 500g.

Test Results of an Experimental Coil with Bi-2212 Rutherford Cable for High Energy-density HTS-SMES

Since FY 2004, a four-year Japanese national project has been ongoing to develop an HTS-SMES as a sub-program of the Development of Superconducting Power Network Control Technology. The purpose of this project is to confirm the performance of a high energy density SMES coil with Bi-2212 cables. This coil system is composed of an NbTi outer coil and a Bi-2212 inner coil, consisting of 16 double pancakes. A Bi2212 cable of 140 m length is used for the double-pancake windings, and reinforcing materials are co-wound with the cable. A winding inner diameter of 360 mm was set according to the bending tolerance of the cable. The magnet is to be cooled at 4.2 K by liquid helium in order to obtain high overall current density. In the first year of this project, a conceptual design and various experiments for HTS magnet were carried out. This paper describes the test results of the HTS experimental coil that was developed to evaluate the electrical and thermal characteristics of an HTS. It is important to minimize deterioration and damage to the cable, because such defects cause fatal impact to the coil. Consequentially, high accuracy measurement of V-I characteristics up to10−8 V/cm range was performed in this experiment.

Flexion and extension structural properties and strengths for male cervical spine segments

New vehicle safety standards are designed to limit the amount of neck tension and extension seen by out-of-position motor vehicle occupants during airbag deployments. The criteria used to assess airbag injury risk are currently based on volunteer data and animal studies due to a lack of bending tolerance data for the adult cervical spine. This study provides quantitative data on the flexion–extension bending properties and strength on the male cervical spine, and tests the hypothesis that the male is stronger than the female in pure bending. An additional objective is to determine if there are significant differences in stiffness and strength between the male upper and lower cervical spine. Pure-moment flexibility and failure testing was conducted on 41 male spinal segments (O–C2, C4–C5, C6–C7) in a pure-moment test frame and the results were compared with a previous study of females. Failures were conducted at approximately 90 N-m/s. In extension, the male upper cervical spine (O–C2) fails at a moment of 49.5 (s.d. 17.6) N-m and at an angle of 42.4° (s.d. 8.0°). In flexion, the mean moment at failure is 39.0 (s.d. 6.3°) N-m and an angle of 58.7° (s.d. 5.1°). The difference in strength between flexion and extension is not statistically significant. The difference in the angles is statistically significant. The upper cervical spine was significantly stronger than the lower cervical spine in both flexion and extension. The male upper cervical spine was significantly stiffer than the female and significantly stronger than the female in flexion. Odontoid fractures were the most common injury produced in extension, suggesting a tensile mechanism due to tensile loads in the odontoid ligamentous complex.

Computer aided process planning for sheet metal bending: A state of the art

Purpose of this paper is to offer the reader an overview of recently performed and ongoing research related to process planning for sheet metal bending, thus providing a starting point for further exploration of this field. The scope of this review paper is limited to sheet metal bending as performed on numerically controlled press brakes, with special focus on air bending. Automatic process planning requires a good understanding of the material behaviour under process conditions. Therefore, some space has been reserved for an overview of bend modelling efforts and, directly linked to this, in-process measurement and adaptive control methods. Part representation and feature classification methods for bent sheet metal parts are also discussed. Sections are dedicated to the core problems of fully automated process planning in sheet metal bending: bend sequencing, collision detection, tolerance verification and tool selection. The state of the art review is completed with an overview of ergonomic analysis methods for process plan evaluation.

Reliable Polymer-Stabilized Ferroelectric Liquid Crystal Device Using Thin Plastic Substrates

We developed a rollable polymer-stabilized ferroelectric liquid crystal (FLC) display device using thin plastic substrates. In a device using 200-μm-thick substrates which are fastened by polymer walls and networks made by photopolymerization-induced phase separation, disorder of the FLC alignment was caused by exfoliation of these walls in curvature radii of under 30 mm. Otherwise, the uniformity of the FLC alignment was maintained even after a device using 100-μm-thick substrates was bent at a radius of 7 mm. The enhanced bending tolerance does not depend on the FLC alignment direction, and the device could be bent both convexly and concavely without any FLC alignment change. A rollable device with a size of 100 × 100 mm exhibited uniform grayscale display operation between crossed polarizers when bent with a radius of 15 mm.

ＰＩＴ法で作製したＭｇＢ２超電導線材及びコイルの臨界電流特性

This paper reports on the successful fabrication and testing of a MgB2 coil. We have fabricated a 15 m-long MgB2/stainless steel mono-core tape using a mixture of commercial MgB2 powder and tin powder (10wt% of MgB2 powder) using the PIT method. The tape is made applying an ex-situ process without any heat treatment during the processing procedure. The MgB2 superconducting tapes show good uniformity, with a high Jc value (180-290 A/mm2 at 4.2 K and 3 T) along the tape's length, as well as good bending tolerance. Ic degradation of the tape occurred at a bending strain of as high as 1.3%. Using wire over 12 m-long, we made a small solenoid coil, 48.5 mm in outer diameter and 40 mm height, and tested it at 4.2 K and self-field. The highest Ic value we obtained was 255 A, which generated a central field of 0.5 T, and a maximum magnetic field of 0.575 T.

Fabrication and transport properties of MgB 2 wire and coil

The paper reports the first successful fabrication and test of a MgB 2 coil. We have fabricated 15 m long MgB 2-superconducting wires by a powder-in-tube method using Ni-sheath without any heat treatments during the processing. The MgB 2/Ni tape has a good uniformity of high J c value (500–600 A/mm 2 at 4.2 K and 0 T) along the tape length as well as a nice bending tolerance. I c degradation of the tape occurred at the bending strain of as high as 1%. Using a 10 m long Ni-sheath tape, we have made a small solenoidal coil with 80 turns to be tested in liquid helium. The coil showed a typical training effect, I c increasing by repeating the excitation, and the highest I c value we obtained was 105 A, which generated the central field of 0.13 T.

Dynamic Bending Tolerance of the Human Forearm

With the wide-spread use of supplemental restraint systems (airbags), occasional new injuries have developed because of the significant force associated with these systems upon deployment. Recent case studies have demonstrated forearm fractures associated with the deployment of the airbag. The present study was conducted to determine the tolerance of the human forearm under a dynamic bending mode. A total of 30 human cadaver forearm specimens were tested using three-point bending techniques to failure at 3.3 m/s and 7.6 m/s velocities. Results indicated significantly (p < 0.01) greater biomechanical parameters associated with males compared to females. The bending tolerance of the human forearm was found to be most highly correlated to bone mineral density and forearm weight. The mean failure bending moment for all specimens was 94 Nm - 41, but for smaller-sized occupants with lower bone mineral it was approximately 45 Nm. The present investigation offers quantitative information regarding tolerance of the human forearm useful for design of injury-mitigating devices.

Objective identification of meanders and bends

Traditional methods of studying meander planform geometry have assumed that meanders contain a single bend or apex and that the inflection points or half-meander endpoints can be identified unambiguously. Along many meandering channel reaches both assumptions are often violated. Accordingly, a distinction is drawn between half-meanders and bends, and a method of objectively identifying these features is developed. This method, termed the planform differencing technique, is based on direction-change measurements made at a fixed interval along the channel and uses a single criterion variable, the half-meander tolerance, to identify half-meanders and bends alike. A second criterion variable, the bend tolerance, is employed to determine the lengths of bends. The planform differencing technique permits meanders and bends to be identified on the basis of explicitly stated quantitative criteria and yields reproducible and spatially consistent results. When the technique is applied to a small meandering stream in western New York, it reveals that almost half the bends do not contain pools. The dearth of pools in relatively open bends is at odds with the idea that bends form at pools by the lateral migration of the outswinging channel thalweg. The development of bends at locations other than pools appears to be caused mainly by inhomogeneities in the bank material.

Fabrication and evaluation of a cryostable Nb&amp;lt;inf&amp;gt;3&amp;lt;/inf&amp;gt;Sn superconductor for the Mirror Fusion Test Facility (MFTF-B)

The MFTF-B magnet system requires two 12.5T, 36 cm bore, insert coils. These coils are being constructed with a cryostable Nb 3 Sn conductor manufactured by Furukawa Electric Co. The conductor consists of a core soldered into a cold-worked copper housing, which provides strength. The Nb 3 Sn core is made by a triple extrusion bronze process. A total of 57 lengths, each 295 m long, have been made and tested. We have made extensive tests on this conductor; these tests include critical current, ambient and 4.2 K mechanical property measurements, critical current as a function of tensile strain, and bending tolerance tests. The critical current density was found to be quite anisotropic in this conductor, with J c (12T) = 650A/mm2for field perpendicular to the conductor wide face, and J c (12T) = 500A/mm2for field parallel to the conductor wide face. These values are among the highest reported for a production lot of Nb 3 Sn conductor.

Replacement of the femoral head by ceramic endoprosthesis. An experimental study on rabbits.

In 31 rabbits the femoral head was replaced by a ceramic endoprosthesis. For 11 of the experimental animals the endoprostheses were made by the Arabia China Factory in Helsinki, and for 20 by Staatliche Porzellan Manufaktur in Berlin. The operation was performed under fully sterile conditions and the follow-up time was between 6 and 34 weeks. The hip joint was examined clinically, roentgenologically, macroscopically and histologically. The bending tolerance of the ceramic endoprosthesis was not adequate. Mechanical loosening of the proximal part of the prosthesis occurred in 68 per cent and was combined with fracture of the prosthetic stem. This created a pseudarthrosis-like reaction in the acetabular area and limited the movement of the hip joint. The distal fragment of the stem was always surrounded by a thin layer of dense bone. In the nonfractured cases (32 per cent), however, the reaction was only moderate and the movement of the hip joint was well preserved. The tissue reactions to the ceramic material were slight, but the great number of secondary reactions following stem fractures make the use of the ceramic endoprosthesis questionable in experiments with rabbits.

Report on New Experiments with Super-conductors : H. Kamerlingh Onnes (Communications, Phys. Lab., Leyden, Supplement No. 50.)

Bending tolerance is one of the most fundamental mechanical properties of REBCO coated conductors for application to a superconducting coil. In this study, we investigated critical current degradation of REBCO coated conductors under bending and uniaxial tensile strain at 77 K and self-field with three different kinds of production from SuperPower Inc, Suzhou Advanced Materials Research Institute (SAMRI) and Shanghai Superconductor Technology (STT), respectively. All the tapes showed better bending tolerance under compressive strain than tensile strain, particularly for STT tapes, which showed no Ic degradation in compressive bending strain even with bending radius of 4.5 mm, but a 5% Ic degradation in tensile strain with bending radius of 6–6.5 mm. A uniaxial tensile strain test was also carried out to verify the dependence of Ic under tensile bending strain, the test results showed a good agreement between them. The tensile strain tolerance was 0.28–0.29% for STT tapes, 0.4–0.43% for SAMRI tapes, and 0.5–0.55% for SuperPower tapes.