Stainless Steel Ring Research Articles

Trapped magnetic-field properties of prototype for Gd-Ba-Cu-O/MgB2 hybrid-type superconducting bulk magnet

We have studied experimentally and numerically the trapped magnetic-field properties of a hybrid-type superconducting bulk magnet, which comprised an inner Gd-Ba-Cu-O (GdBCO) disk-bulk and an outer MgB2 ring-bulk, under field-cooled magnetization (FCM) and pulsed-field magnetization (PFM). The trapped field by FCM at the center of the hybrid bulk was 4.5 T at 20 K, which was 0.2 T higher than that of the inner GdBCO disk-bulk without MgB2 ring-bulk. The experimental results by FCM were quantitatively reproduced by the numerical estimations for a model, which makes it possible to understand the trapped field properties of the hybrid bulk. The total magnetic flux by FCM, which was estimated numerically, was enhanced by about 1.7 times from 0.91 mWb of the single GdBCO bulk to 1.53 mWb of the hybrid bulk. We also succeeded in magnetizing the whole hybrid bulk by applying multi-pulsed-fields. The central trapped field of 1.88 T was not enhanced, but the total magnetic flux, which was obtained experimentally, was evidently increased by 2.5 times (0.25 0.62 mWb) for the hybrid bulk. The obtained results suggest that the hybridization is effective to enhance the total magnetic flux. To confirm the reinforcing effect of the MgB2 ring to the GdBCO disk during the cooling and magnetization processes, we have measured the thermal dilatation, , of the GdBCO, MgB2 and stainless steel. As a result, the thermal dilatation of MgB2 was smaller than that of GdBCO. MgB2 ring-bulk shows no compression effect to resist the hoop stress of the GdBCO disk-bulk during the FCM process. The reinforcing material such as the stainless steel ring must be set outside the GdBCO disk-bulk.

Chinese IUD removal techniques in a Chinese population in central Italy

To describe routine techniques and a newly developed approach to the removal of Chinese intrauterine devices (IUs).Office records regarding women of Chinese nationality who presented to a tertiary care hospital for IUD removal between January 2007 and March 2012 were retrieved. Their demographic data were reviewed and menstrual/obstetric history, IUD type, and reasons given for removal were recorded. All underwent pelvic transvaginal ultrasound scanning.Of 134 Chinese IUDs, 18 (13.4%) were removed successfully in an office setting using a hook or uterine curette without general anesthesia or cervical dilation. Extraction under brief general anesthesia was performed in 55 (41.0%) cases. A further 61 (45.5%) Chinese IUDs were successfully removed in an office setting using a miniature resectoscope. Four types of Chinese IUDs were removed, the most common being the stainless steel ring (55.7%).All removal procedures were effective and safe. The mini-resectoscope appears to be a safe and effective tool enabling minimally invasive surgery.

The electro-spraying characteristics of ethanol for application in a small-scale combustor under combined electric field

A small-scale combustor with electro-spraying technique was investigated. It consisted of vertical quartz glass tubes with an inner diameter of 16.0 mm. A stainless steel ring and a stainless steel mesh were used as an extractor and a collector, respectively. A capillary tube with an inner diameter of 0.9 mm was used as a nozzle. The nozzle and the steel ring were connected to the positive electrode of Direct Current power sources. The steel mesh was the droplets collector and a flame holder. Stable combustion flame was observed under combined electric fields. The electro-spraying modes of pulsed-jet, cone-jet, skewed cone-jet, and multi-jet were observed. The operating ranges were divided into several regions at various voltages and flow rates. The whole fluid field was divided into the jet region and spraying region. The driving force in the jet region came from the electrostatic induction field between the nozzle and the steel ring. The electric field between the steel ring and steel mesh supplied the driving force to move liquid droplets in the spraying region. The steel mesh is a key component for the directional movement of liquid droplets. Taylor angles measured at cone-jet mode were in the range of 75.18°–82.45°.

Effect of Phosphoric Acid Pre-etching on Fatigue Limits of Self-etching Adhesives.

The purpose of this study was to use shear bond strength (SBS) and shear fatigue limit (SFL) testing to determine the effect of phosphoric acid pre-etching of enamel and dentin prior to application of self-etch adhesives for bonding resin composite to these substrates. Three self-etch adhesives--1) G- ænial Bond (GC Corporation, Tokyo, Japan); 2) OptiBond XTR (Kerr Corp, Orange, CA, USA); and 3) Scotchbond Universal (3M ESPE Dental Products, St Paul, MN, USA)--were used to bond Z100 Restorative resin composite to enamel and dentin surfaces. A stainless-steel metal ring with an inner diameter of 2.4 mm was used to bond the resin composite to flat-ground (4000 grit) tooth surfaces for determination of both SBS and SFL. Fifteen specimens each were used to determine initial SBS to human enamel/dentin, with and without pre-etching with a 35% phosphoric acid (Ultra-Etch, Ultradent Products Inc, South Jordan, UT, USA) for 15 seconds prior to the application of the adhesives. A staircase method of fatigue testing (25 specimens for each test) was then used to determine the SFL of resin composite bonded to enamel/dentin using a frequency of 10 Hz for 50,000 cycles or until failure occurred. A two-way analysis of variance and Tukey post hoc test were used for analysis of SBS data, and a modified t-test with Bonferroni correction was used for the SFL data. Scanning electron microscopy was used to examine the area of the bonded restorative/tooth interface. For all three adhesive systems, phosphoric acid pre-etching of enamel demonstrated significantly higher (p<0.05) SBS and SFL with pre-etching than it did without pre-etching. The SBS and SFL of dentin bonds decreased with phosphoric acid pre-etching. The SBS and SFL of bonds using phosphoric acid prior to application of self-etching adhesives clearly demonstrated different tendencies between enamel and dentin. The effect of using phosphoric acid, prior to the application of the self-etching adhesives, on SBS and SFL was dependent on the adhesive material and tooth substrate and should be carefully considered in clinical situations.

A Multifrequency Notch Filter for Millimeter Wave Plasma Diagnostics based on Photonic Bandgaps in Corrugated Circular Waveguides

Sensitive millimeter wave diagnostics need often to be protected against unwanted radiation like, for example, stray radiation from high power Electron Cyclotron Heating applied in nuclear fusion plasmas. A notch filter based on a waveguide Bragg reflector (photonic band-gap) may provide several stop bands of defined width within up to two standard waveguide frequency bands. A Bragg reflector that reflects an incident fundamental TE11 into a TM1n mode close to cutoff is combined with two waveguide tapers to fundamental waveguide diameter. Here the fundamental TE11 mode is the only propagating mode at both ends of the reflector. The incident TE11 mode couples through the taper and is converted to the high order TM1n mode by the Bragg structure at the specific Bragg resonances. The TM1n mode is trapped in the oversized waveguide section by the tapers. Once reflected at the input taper it will be converted back into the TE11 mode which then can pass through the taper. Therefore at higher order Bragg resonances, the filter acts as a reflector for the incoming TE11 mode. Outside of the Bragg resonances the TE11 mode can propagate through the oversized waveguide structure with only very small Ohmic attenuation compared to propagating in a fundamental waveguide. Coupling to other modes is negligible in the non-resonant case due to the small corrugation amplitude (typically 0.05·λ0, where λ0 is the free space wavelength). A Bragg reflector for 105 and 140 GHz was optimized by mode matching (scattering matrix) simulations and manufactured by SWISSto12 SA, where the required mechanical accuracy of ± 5 μm could be achieved by stacking stainless steel rings, manufactured by micro-machining, in a high precision guiding pipe. The two smooth-wall tapers were fabricated by electroforming. Several measurements were performed using vector network analyzers from Agilent (E8362B), ABmm (MVNA 8-350) and Rohde&Schwarz (ZVA24) together with frequency multipliers. The stop bands around 105 GHz (- 55dB) and 140 GHz (-60dB) correspond to the TE11-TM12 and TE11-TM13 Bragg resonances. Experiments are in good agreement with theory.

Solubility of a new calcium silicate-based root-end filling material.

Introduction:The purpose of this study was to compare solubility of a new calcium silicate-based cement, Biodentine with three commonly used root-end filling materials viz. glass-ionomer cement (GIC), intermediate restorative material (IRM), and mineral trioxide aggregate (MTA).Materials and Methods:Twenty stainless steel ring molds were filled with cements corresponding to four groups (n = 5). The weight of 20 dried glass bottles was recorded. Samples were transferred to bottles containing 5 ml of distilled water and stored for 24 h. The bottles were dried at 105΀C and weighed. This procedure was repeated for 3, 10, 30, and 60 days. Data was analyzed with one-way analysis of variance (ANOVA) test (P < 0.05).Results:Biodentine demonstrated significantly higher solubility than MTA for 30- and 60-day immersion periods. Statistical difference was noted between the solubility values of Biodentine samples amongst each of the five time intervals.Conclusions:Biodentine exhibited higher solubility in comparison with all other cements.

First results of KALI-30 GW with 1 MV flash X-rays generation and characterization by Imaging plate

The design, development and commissioning of 1 MV pulsed electron accelerator producing Flash X-Rays is described in this paper. This pulsed power system is based on bipolar MARX generator and Blumlein followed by Explosive electron emission diode assembly. The peak pulsed power is ∼ 30 GW. The electron energies in the range of 400 keV to 1030 keV are produced and delivered to experimental load of Industrial diode. Electrons are emitted from a stainless steel ring at ground potential by explosive field emission and bombard the anode tungsten pin for flash X-rays generation. The relativistic electron beam has been simulated within the diode chamber and pattern shows the beam propagation. Imaging plates are used to characterize the source size and optimization has been reported.

Measurement and Prediction of Residual Stresses in Quenched Stainless Steel Components

Austenitic stainless steel cylinders and rings are spray water quenched to create residual stresses at or greater than the yield strength. The residual stresses are measured using neutron diffraction, and two mechanical strain relaxation methods: deep hole drilling and incremental centre hole drilling. This paper compares the measurements with predictions of quenching using finite element analysis. Also finite element analysis is used to mimic deep hole and incremental centre hole drilling methods and to reconstruct residual stresses as if they have been measured. The measurements reveal similar trends to the predictions but there is only limited agreement between their magnitudes. However, there is better agreement between the reconstructed stresses and the measurements. Both the two mechanical strain relaxation methods reveal that large discrepancies occur between measurements and predictions arise because of plasticity. Irrespective of this and surprisingly there is good agreement between deep hole drilling and neutron diffraction measurements.

Hot gas bulging of sealed aluminium alloy tube using resistance heating

A hot gas bulging process of a sealed aluminium alloy tube using resistance heating was developed to simplify a control scheme in gas forming. The tube is bulged by the decrease in flow stress of the tube and the increase in internal pressure of compressed air during resistance heating. Hot gas bulging of the sealed aluminium alloy tube without and with axial feeding was performed. The effects of the initial internal pressure and the current density on the expansion ratio of the tube were examined. The decrease in temperature around the contact with the electrode was prevented by inserting a stainless steel ring having low thermal conductivity and high heat generation between the copper electrode and tube, and thus the bulging length was increased. It was found that the amount of bulging can be controlled for the sealed tube by heating without control of internal pressure during forming.

Bonded bimaterial ring under compressive load

A bonded ring test is proposed to study crack onset under pure and mixed mode conditions. In the existing centre-cracked Brazilian disc configuration, introduction of a central crack may be arbitrary and can easily lead to initial asymmetric crack configuration. Moreover, the crack front geometry is, in general, unknown which may result in serious consequences on crack onset and fracture parameters. In the present work, a bonded ring loaded in compression was investigated numerically and experimentally. Two bimaterial singular points were introduced between the half discs and the adhesive providing privileged crack onset location – controllable during specimen fabrication. Three types of specimens were analysed using digital image correlation and finite element techniques: homogenous poly(methyl methacrylate), bonded poly(methyl methacrylate) and bonded poly(methyl methacrylate) to stainless steel rings. A satisfying agreement between experimental and numerical approaches was found enabling more complex analysis in future. Such test configuration can be of interest for crack onset studies and estimation of fracture parameters under mixed mode I/II loading conditions.

Stomatin‐domain protein interactions with acid‐sensing ion channels modulate nociceptor mechanosensitivity

Acid-sensing ion channels (ASICs) and their interaction partners of the stomatin family have all been implicated in sensory transduction. Single gene deletion of asic3, asic2, stomatin, or stoml3 all result in deficits in the mechanosensitivity of distinct cutaneous afferents in the mouse. Here, we generated asic3−/−:stomatin−/−, asic3−/−:stoml3−/− and asic2−/−:stomatin−/− double mutant mice to characterize the functional consequences of stomatin–ASIC protein interactions on sensory afferent mechanosensitivity. The absence of ASIC3 led to a clear increase in mechanosensitivity in rapidly adapting mechanoreceptors (RAMs) and a decrease in the mechanosensitivity in both Aδ- and C-fibre nociceptors. The increased mechanosensitivity of RAMs could be accounted for by a loss of adaptation which could be mimicked by local application of APETx2 a toxin that specifically blocks ASIC3. There is a substantial loss of mechanosensitivity in stoml3−/− mice in which ∼35% of the myelinated fibres lack a mechanosensitive receptive field and this phenotype was found to be identical in asic3−/−:stoml3−/− mutant mice. However, Aδ-nociceptors showed much reduced mechanosensitivity in asic3−/−:stoml3−/− mutant mice compared to asic3−/− controls. Interestingly, in asic2−/−:stomatin−/− mutant mice many Aδ-nociceptors completely lost their mechanosensitivity which was not observed in asic2−/− or stomatin−/− mice. Examination of stomatin−/−:stoml3−/− mutant mice indicated that a stomatin/STOML3 interaction is unlikely to account for the greater Aδ-nociceptor deficits in double mutant mice. A key finding from these studies is that the loss of stomatin or STOML3 in asic3−/− or asic2−/− mutant mice markedly exacerbates deficits in the mechanosensitivity of nociceptors without affecting mechanoreceptor function.

An experimental device to study the revaporisation behaviour of fission product deposits under severe accident conditions

The uncontrolled release into the environment of radioactive fission products (FPs) produced in nuclear fuel is the main threat in case of a severe reactor accident. The chemical state of the FPs and their interaction with the surfaces inside the containment and with the atmosphere have great influence on their mobility and thus on the release source term. A revaporisation device was built to provide experimental data on fission product transport and deposition for severe accident codes (e.g. ASTEC). The other aim was to study in detail revaporisation processes associated with different stages of a severe accident involving fuel degradation including melting.The device allows us to study the transport behaviour of gamma-emitting FPs under oxidising and reducing conditions over the temperature range 200–1000 °C at ambient pressure. A lanthanum (III)-bromide (LaBr3) detector is used to measure the amount of revaporised FPs as a function of time and temperature.This paper describes the main features of this device, including a series of upgrades on-going or planned to extend the applicable range of FPs and atmosphere conditions. Test results of FPs deposited on the surface of stainless steel rings from the upper vertical line of the Phébus FP tests are presented. Experiments under steam atmosphere showed that revaporisation of 137Cs starts at 540 °C progressing rapidly until near the total depletion of the deposit, resulting in a total revaporisation of ∼92%.

Monotonic and cyclic behavior of densely confined concrete using stainless steel rings

This study suggests a dense lateral reinforcement for a Reinforced Concrete (RC) column whose spacing is smaller than the maximum gravel size. This study conducts axial compressive tests of concrete cylinders confined by dense reinforcement to verify the effectiveness of the dense lateral reinforcement. Stainless steel rings are used for the reinforcement since they are corrosion resistant. The dense reinforcing method with stainless steel rings successfully increases the peak strength of the concrete. The strains at the peak strength are much larger than those for the concrete confined by a conventional method with steel reinforcing bars. The failure mode of concrete densely confined by steel rings is due to the gradual fracture of each ring; the fracture of each ring reduces the stress on the concrete. The cyclic behavior of the densely confined concrete is similar to that of concrete confined by conventional steel reinforcement.

Numerical investigation for the effect of the liquid film volume on thermocapillary flow direction in a thin circular liquid film

NASA Astronaut Dr. Pettit carried out a thermocapillary flow experiment onboard the International Space Station in 2003. In this experiment a thin water film containing milk powder was formed in a stainless-steel wire ring. Heating a section of the ring by a soldering iron induced in the water film a thermocapillary flow towards the heated section of the ring (outward flow: cold to hot). This flow was in the opposite direction of the usually observed thermocapillary flows (inward flow: hot to cold). To shed light on this interesting phenomenon observed in the space experiment, we have conducted a three-dimensional numerical simulation study. Simulation results showed that the film geometry of the water film is a key factor determining flow direction and flow strength. When the liquid film free surfaces are convex, i.e., the water film volume is larger than that when the free surfaces are flat, an outward flow develops in the film as observed in the space experiment. However, when the free surfaces are concave, the simulation predicts an inward flow.

Shrinkage stress compensation in composite-restored teeth: Relaxation or hygroscopic expansion?

ObjectivesPolymerization of composite restorations causes shrinkage, which deforms and thus stresses restored teeth. This shrinkage deformation, however, has been shown to decrease over time. The objective was to investigate whether this reduction was caused by hygroscopic expansion or stress relaxation of the composite/tooth complex. MethodsExtracted molars were mounted in rigid stainless steel rings with four spherical reference areas. Twelve molars were prepared with large mesio-occluso-distal slots, etched, bonded, and restored with a composite material (Filtek Supreme, 3M ESPE) in two horizontal layers. Ten intact molars were the controls. The teeth were stored either in deionized water or silicone oil. They were scanned after preparation (baseline), restoration (0-week), and after 1, 2, and 4 weeks storage. Scanned tooth surfaces were aligned with the baseline using the unchanged reference areas. Cuspal flexure was calculated from lingual and buccal surface deformation. To verify that the restorations had remained bonded, dye penetration at the interfaces was assessed using basic fuchsin dye. Statistical assessment was done by ANOVA followed by Student–Newman–Keuls post hoc test (p=0.05). ResultsSubstantial cuspal contraction was found for restored teeth after the composite was cured (13–14μm cuspal flexure). After 4 weeks cuspal contraction decreased significantly for restored teeth stored in water (7.3±3.2) but not for those stored in silicone oil (11.4±5.0). Dye penetration of the occlusal interface was minimal in both groups (106±87 and 21±28μm in water and silicone oil, respectively). SignificanceThe results suggest that hygroscopic expansion was the main mechanism for shrinkage stress compensation.

Delayed linear dimensional changes of five high strength gypsum products used for the fabrication of definitive casts

Prolonged storage of definitive casts made from Type IV and Type V gypsum products, especially in an environment of increased temperature and low humidity, may result in contraction. The purpose of this study was to evaluate the linear dimensional changes of 5 different high strength stones after exposing them to 2 different storage conditions over a period of 3 weeks. Three Type IV dental stones (Fujirock, Vel-Mix, Suprastone) and 2 Type V dental stones (Hard Rock, Jade Stone) were tested in this study. A circular conical stainless steel die with a diameter of 66 mm and a height of 10 mm was made. Two V-shaped grooves, 38 mm apart, were scribed on the surface of the die for the purposes of measurement. A conical stainless steel ring with a bottom inner diameter of 68 mm and a top inner diameter of 65 mm was also fabricated to fit precisely around the stainless steel die. The dental stone was mixed with water under vacuum and poured under vibration onto the stainless steel die, which was surrounded by the ring. The specimens (n=20) were separated from the stainless steel die 1 hour after pouring. Half of these specimens (control) were stored in a room at 22 ±1°C with relative humidity of 50 ±5%, while the rest of the specimens were placed in a temperature regulating incubator at 40 ±1°C and relative humidity of <20%. The linear dimensional changes were recorded at designated time intervals with a traveling microscope over a 3 week period. Collected data were subjected to a 2-way repeated-measures analysis of variance (ANOVA) (α=.05). The highest expansion values for the specimens in the control group were recorded between 72 and 96 hours. A contraction was noticed thereafter for all specimens, in both groups. No difference in the measurements was registered between the second and third week. ANOVA revealed significant differences (P<.001) among different Type IV and V dental stone products, time, and storage conditions. The highest expansion values for all specimens in the control group were recorded between 72 and 96 hours. The highest expansion values for all specimens in the experimental group were recorded at 24 hours. For all specimens, contraction was noticed up to the 2-week measurements. All factors examined (dental stone, time, storage condition) significantly affected the linear dimensional changes.

Confined compression and torsion experiments on a pHEMA gel in various bath concentrations

The constitutive behaviour of cartilaginous tissue is the result of complex interaction between electrical, chemical and mechanical forces. Electrostatic interactions between fixed charges and mobile ions are usually accounted for by means of Donnan osmotic pressure. Recent experimental data show, however, that the shear modulus of articular cartilage depends on ionic concentration even if the strain is kept constant. Poisson-Boltzmann simulations suggest that this dependence is intrinsic to the double-layer around the proteoglycan chains. In order to verify this premise, this study measures whether--at a given strain--this ionic concentration-dependent shear modulus is present in a polymerized hydroxy-ethyl-methacrylate gel or not. A combined 1D confined compression and torque experiment is performed on a thin cylindrical hydrogel sample, which is brought in equilibrium with, respectively, 1, 0.1 and 0.03 M NaCl. The sample was placed in a chamber that consists of a stainless steel ring placed on a sintered glass filter, and on top a sintered glass piston. Stepwise ionic loading was cascaded by stepwise 1D compression, measuring the total stress after equilibration of the sample. In addition, a torque experiment was interweaved by applying a harmonic angular displacement and measuring the torque, revealing the relation between aggregate shear modulus and salt concentration at a given strain.

Tribological Characteristics of DLC Coatings in Vacuum under Sliding Contact

Diamond-like Carbon (DLC) coatings of thickness 3 μm and 10 μm were deposited with and without radical nitriding on stainless steel disk and ring specimens. Plasma CVD method was used to deposit the DLC coatings with silicon as dopant. The specimens were tested in vacuum under sliding contact condition to evaluate the tribological characteristics with reference to the DLC coating thickness and sliding distance. The results revealed that wear resistance was more for the highest coating thickness. The changes on the worn surfaces were observed and wear mechanism is discussed using ex situ analysis.

Modelling and simulation of a novel giant magnetostrictive force sensor

Utilising a giant magnetostrictive material (GMM) rod as the sensitive element, a new type of magnetostrictive force sensor is studied. A Hall sensor with a stainless steel ring integrated in the sensor is used to measure the bias magnetic field intensity. In view of the hysteresis of GMM, a model for the sensor is established based on Jiles–Atherton model and magnetomechanical effect method. Moreover, the numerical solution method and simulation process of the model are expounded in detail. The simulation results show that the model can reveal the process mechanism of magnetisation and have a good ability in describing the hysteretic non-linearity. The experimental results indicate that the model can effectively describe the relationship between the induced voltage and force under a constant magnetic field and dynamic force simultaneously.

Model NbTi Helical Solenoid Fabrication and Test Results

A program to develop model magnets for a helical cooling channel is under way at Fermilab. In the first steps of a planned sequence of magnets, two four-coil helical solenoid models with 300 mm aperture have been fabricated and tested. These two models, HSM01 and HSM02, used insulated NbTi Rutherford cable wound onto stainless steel rings with spliceless transitions between coils. Strip heaters were included for quench protection of each coil, and the coils were epoxy-impregnated after winding inside the support structures. Based on the results of the first model the second model was made using a cable with optimized cross-section, improved winding and epoxy-impregnation procedures, enhanced ground insulation, and included heat exchange tubing for a test of conduction cooling. We report on the results and lessons learned from fabrication and tests of these two models.