Wire Type Research Articles

Clinical outcomes of closed, displaced phalangeal neck fractures in children with different types of kirschner wire fixation: A retrospective observational study.

Inappropriate treatment of Closed displaced phalangeal neck fractures (CDPNF) in children usually leads to poor outcomes.This study was to evaluate the clinical outcomes of closed/open reduction, age, and different types of fracture and Kirschner wire (K-wire) fixation in the treatment of CDPNF. Participants: Sixty patients (male, 46 and female,14; right-handed, 35 and left-handed, 25; mean age, 7.9-years-old [range, 1.0-14.5 years]) who had CDPNF were included. Preoperative x-rays showed that the fractures were displaced and exhibited obvious deformities. Interventions: First, reduction (four cases of open reduction and 56 cases of closed reduction) was performed followed by percutaneous K-wire fixation (cross fixation, 24 cases; longitudinal and slanting fixation, 17 cases; homolateral fixation, four cases; and single longitudinal fixation, 15 cases,) and immobilized by cast. x-ray examination following removal of the K-wires showed that the fractures were healed; the criteria for fracture healing were callus formation and the absence of fracture lines. Clinical outcome and radiographs between groups were compared. According to the visual analogue scale, the pain scores were excellent. According to the Al-Qattan Grade system(AGS),all the patients presented with closed, type II phalangeal neck fractures,the results were excellent in 36 cases (36/60, 60%), good in 15 cases (15/60, 25%), fair in 5 cases (5/60, 8.3%) and poor in 4 cases (4/60, 6.7%). There were significant differences in different fracture type groups (P = 0.013*), operation age groups (P = 0.025*) and open/closed reduction groups (P = 0.042*). There was no significant difference in K-wire fixation type groups (P > 0.05). Patients with open reduction, the more serious fracture type, the older at the operation, were more likely to have poor AGS result. Different K-wire fixation types for CDPNF in children had the same satisfactory results.

Comparative Study on Laser Welding Thick-Walled TC4 Titanium Alloy with Flux-Cored Wire and Cable Wire

In the welding process of thick-walled titanium alloys, the selection of the wire type is one of the critical factors affecting the welding quality. In this paper, flux-cored and cable wires were used as filler materials in the welding of thick-walled titanium alloys. The macrostructure, microstructure, texture, and grain size of both welded joints were compared by employing an optical microscope (OM), scanning electron microscope (SEM), and transmission electron microscope (TEM), and the tensile and impact properties were also evaluated. The comparison result showed that the fusion zone microstructure of both welded joints was dominated by a basketweave structure composed of interwoven acicular α' martensite, whereas the microstructure of flux-cored wire welded joints was finer, and the degree of anisotropy was low. The strength of both welded joints was higher than that of the base metal, ensuring that fracture occurred in the base metal area during tension. The Charpy impact energy of the flux-cored wire welded joint was 16.7% higher than that of the cable wire welded joint, indicating that the welded joint obtained with the flux-cored wire performed better in the welding process of thick-walled titanium alloys.

Deserted Devices and Wasted Fences: Everyday Technologies in Extreme Circumstances

Deserted Devices and Wasted Fences: Everyday Technologies in Extreme Circumstances

Corrosion Fatigue Degradation Characteristics of Galvanized and Galfan High-Strength Steel Wire.

Cables are the main load-bearing components of a cable bridge and typically composed of high strength steel wires with a galvanized coating or Galfan coating. Galfan steel wire has recently started to be widely used because of its better corrosion resistance than galvanized steel wire. The corrosion characteristics of the coating and the difference in the corrosion fatigue process of the two types of steel wire are unclear. To further improve the service performance and maintenance of cable bridges, this study investigated the corrosion characteristics of galvanized steel wire and Galfan steel wire through accelerated corrosion tests and established a time-varying model of uniform corrosion and pitting corrosion of high-strength steel wire. Then, a long-span suspension bridge was taken as the research object, and the corrosion fatigue degradation of the two kinds of steel wire under a traffic load was analyzed on the basis of traffic monitoring data. The results showed that the uniform corrosion of the two types of steel wire conformed to an exponential development trend, the corrosion coefficient of galvanized steel wire conformed to the normal distribution, and the corrosion coefficient of Galfan steel wire conformed to the Cauchy distribution. The maximum pitting coefficient distribution of the two kinds of steel wire conformed to the generalized extreme value distribution. The location parameters and scale parameters of the two distributions showed an exponential downward trend with the increase of corrosion duration. When the traffic intensity was low, the corrosion characteristics of the steel wire was the main factor affecting its service life, and the average service life of Galfan steel wire was significantly higher than that of galvanized steel wire. Under a dense traffic flow, the service life of the steel wire was mainly controlled by the traffic load, and the service life of Galfan steel wire was slightly improved. Effective anti-corrosion measures are a key factor for improving the service life of steel wire.

Reducing cardiac tamponade caused by temporary pacemaker perforation in transcatheter aortic valve replacement

BackgroundCardiac tamponade caused by temporary right ventricular (RV) pacemaker perforation is a rare but serious complication in transcatheter aortic valve replacement (TAVR). AimsTo study the incidence of temporary pacemaker related cardiac tamponade in TAVR, and the relation to the type of pacemaker lead used in periprocedural temporary transvenous pacing. MethodsA single center registry of transfemoral TAVRs in 2014–2020. Main inclusion criterion was peri-operative use of a temporary RV pacing lead. Main exclusion criteria were a preoperatively implanted permanent pacemaker or the exclusive use of left ventricular guidewire pacing. Incident cardiac tamponade was classified as pacemaker lead related, or other. Patients were grouped according to type of temporary RV pacing wire. Results810 patients were included (age 80.5 ± 7.3 [mean ± standard deviation], female 319, 39.4%). Of these, 566 (69.9%) received a standard RV temporary pacing wire (RV-TPW), and 244 (30.1%) received temporary RV pacing through a permanent, passive pacemaker lead (RV-TPPL). In total, 18 (2.2%) events of cardiac tamponade occurred, 12 (67%) were pacemaker lead related. All pacemaker lead-related cardiac tamponades occurred in the group who received a standard RV-TPW and none in the group who received RV-TPPL (n = 12 [2.1%] vs. n = 0 [0%], p = 0.022). No difference in cardiac tamponade due to other causes was seen between the groups (p = 0.82). ConclusionsThe use of soft-tip RV-TPPL was associated with a lower risk of pacemaker related cardiac tamponade in TAVR. When perioperative pacing is indicated, temporary RV-TPPL may contribute to a significant reduction of cardiac tamponade in TAVR.

INCREASING THE WEAR RESISTANCE OF HEAVY LOADED FRICTION UNITS OF ANTI-FRICTION GAS THERMAL COATINGS

Purpose. The purpose of this study is to establish technological conditions and parameters for obtaining materials for improving the performance of machine parts under conditions of heavily loaded friction units due to quasi-tribosystems of gas thermal sprayed anti-friction layers.
 Research methods. Priori data were used in combination with our own scientific developments of the dependences of the influence of the chemical composition of gas thermal sprayed anti-friction layers on the physical and mechanical properties of the surface layer of the material, which is destroyed under tribosystem conditions.
 Results. On the basis of the theoretical and practical scientific research, a set of relevant knowledge has been obtained, which makes it possible to determine the main criteria requirements for obtaining anti-friction layers and graphically describe the characteristics of the alloy and show the correlations of the parameters with each other. The positive role of aluminum as a soft component of anti-friction pseudoalloys, which is well sprayed by thermal metallization at an affordable cost, has been experimentally confirmed. It has been proven that gas thermal coatings in the form of pseudoalloys, consisting of particles with different physical and mechanical properties of materials, can have up to 2–3 times higher wear resistance compared to single-component coatings from materials included in the composition.
 Scientific novelty. Theoretical and practical scientific research with the reproduction of system analysis to increase the resistance to destruction under the conditions of quasi-tribosystems of gas thermal sprayed antifriction layers is given. It is shown that in order to ensure a good running in of the contacting surfaces in the friction zone and particles of hard material with high wear resistance and resistance against sticking with the counterbody, anti-friction pseudoalloys of coatings should contain zones of material particles with lower hardness to comply with the Charpy principle. It has been determined that when spraying composite wires for application as a solid component of anti-friction coatings, it is possible to use particles of alloying elements that form intermetallic compounds or phase components of alloys with a high hardness during melting. A comparative analysis showed that two-component coatings deposited with composite wires are characterized by higher hardness and wear resistance under high contact pressures compared to coatings of the same composition deposited with different types of solid wires.
 Practical value. The obtained results allow, within the framework of technical and technological accuracy, which is necessary in the practical engineering forecasts, to determine the physical and mechanical properties of wear resistant gas thermal sprayed anti-friction layers under conditions of quasi-tribosystems. Thus, in comparison with cast antifriction materials of the same composition, anti-friction layers obtained by thermal metallization have a 1.5–1.8 times higher wear resistance.

Over-the-Scope-Clips Can Be Fired Safely Over a Guidewire: Proof of Concept in an Ex-Vivo Porcine Model.

To assist in achieving optimal position when deploying over-the-scope (OTS)-clips, the concept of cannulating the defect with a guidewire, backloading the endoscope onto the wire, and firing the OTS-clip over the wire with subsequent wire removal has been demonstrated. The safety of this technique has not been evaluated. An ex-vivo porcine foregut model was utilized. Biopsy punches were used to create 3-mm diameter full-thickness gastrointestinal tract defects through which a guidewire was threaded. An endoscope was backloaded over the wire and OTS-clips (OVESCO, Tuebingen, Germany) were fired over the mucosal defect and wire. The wire was removed through the endoscope and the removal difficulty was graded using a Likert scale. This process was repeated for each unique combination of nine OTS-clip types, two wire types, four wire angles, and three tissue types. Statistical analysis included t test and ANOVA. Two hundred sixteen OTS-clip firings with wire removal attempts were performed with the following Likert score breakdown: 1 - No difficulty (80.6%), 2 - mild difficulty (16.2%), 3 - moderate difficulty (2.3%), 4 - extreme difficulty (0.9%), and 5 - unable to remove (0%). Statistically significant differences were noted in removal difficulty between OTS-clip sizes (p < 0.05). No differences were identified between clip teeth types, wire types, tissue types, and wire angles (p > 0.05). In this ex-vivo model, the guidewire was successfully removed through the endoscope in all cases. This technique can be employed to facilitate OTS-clip closure of gastrointestinal tract defects, but further study is indicated before wide clinical implementation.

Investigation of WEDM parameters on Material Removal Rate and Plane Roughness of AISI4130 steel

Wire electrical discharge machine is a unconventional machining process. In WEDM Process more or less conductive materials only able to machined it. In WEDM material is removal from the work piece by continuous release of spark linking the work piece and the wire electrode. AISI 4130 low alloy steel is in recent times developed advanced materials having excellent material properties which will be used for aerospace and oil gas industry applications. In this paper the Experiments are conducted by using Tanguchi’s L18 orthogonal array and five input parameter voltage, current, pulse off time, pulse on time, wire type. Appling the ANOVA to conclude most significant machining parameter is voltage for the material removal rate and Plane Roughness

Favorable treatment outcomes and shorter durations: a retrospective case series on seven patients using Orthoworld FASTBRACES®

Objective: This retrospective case series aimed to evaluate the effectiveness and user experience of Orthoworld FASTBRACES® in seven patients undergoing orthodontic treatment. Emphasizing these specific patients was essential for assessing the shorter treatment duration compared to reported treatment ranges of 12 to 14 months for FASTBRACES® Technologies. Data and images were collected from cases treated between 2016 and 2023, and a Treatment Evaluation Form was sent to participating doctors to gather information about patient experiences with the product. Materials and methods: The seven patients included in the study received orthodontic treatment with FASTBRACES® at various orthodontic practices. The Treatment Evaluation Form completed by participating providers included questions related to treatment details, number of visits, types of brackets and wires used, issues encountered during treatment, patient understanding of treatment, overall comfort level, compliance, and satisfaction with treatment speed. Results: The analysis of patient data revealed variability in patient compliance with treatment protocols and understanding of treatment, with scores ranging from 2 to 4 on the respective scales. The number of brackets used ranged from 10 to 28, and the number of wires utilized ranged from 1 to 4. Most patients reported minimal issues during treatment, with only one reported issue in two cases. Overall, patients reported a high level of comfort, with an average score of 3.43 out of 4. Conclusion: The findings highlight the importance of patient education and communication in promoting better compliance and treatment success. The variability in bracket and wire utilization suggests that the severity and complexity of malocclusions may influence the treatment approach. FASTBRACES® demonstrated success in minimizing patient discomfort, achieving faster alignment, and enhancing overall satisfaction. Further research is needed to investigate the factors underlying differences between the metal and ceramic bracket groups and explore mechanisms behind reported issues. The study underscores the significance of precise bracket and wire placement and the expertise of orthodontic practitioners throughout the treatment process. This case series provides valuable insights into the effectiveness and user experience of Orthoworld FASTBRACES® and lays the groundwork for future research and larger-scale studies.

An Optimized GIB Routing Architecture with Bent Wires for FPGA

Field-programmable gate arrays (FGPAs) are widely used because of the superiority in flexibility and lower non-recurring engineering cost. How to optimize the routing architecture is a key problem for FPGA architects because it has a large impact on FPGA area, delay, and routability. In academia, the routing architecture is mainly based on the connection blocks (CBs) and switch blocks (SBs), whereas most research has focused on SB architectures, such as Wilton, Universal, and Disjoint SB patterns. In this article, we propose a novel unidirectional routing architecture—general interconnection block (GIB)—to improve FPGA performance. With the GIB architecture, logic block (LB) pins can directly connect with the adjacent GIBs without programmable switches. Inside a GIB, LB pins can connect to the routing channel tracks on the four sides of a GIB. In particular, the logic pins from different neighboring LBs that connect to the same GIB can connect with each other with only one programmable switch. In addition, we enhance VTR to support the GIB with bent wires and develop a searching framework based on the simulated annealing algorithm to search for a near-optimal distribution of wire types. We evaluate the GIB architecture on VTR 8 with the provided benchmark circuits. The experimental results show that the GIB architecture with length-4 wires can achieve 9.5% improvement on the critical path delay and 11.1% improvement on the area-delay product compared to the VTR CB-SB architecture with length-4 wires. After exploring mixed wire types, the optimized GIB architecture can further improve the delay by 16.4% and area-delay product by 17.1% compared to the CB-SB architecture with length-4 wires.

Machine vision-based transverse vibration measurement of diamond wire

Diamond wire sawing is one of the key technologies for wafering in the semiconductor industry. The transverse vibration of the wire during sawing will generate additional displacement that not only reduces the as-cut wafer quality but increases the critical adhesion gap between the wires, which is an important factor limiting the development of diamond wire slicing technology toward narrower kerf loss and thinner as-cut wafer. The vibration measurement of the diamond wire provides an indispensable test basis for its vibration control. Therefore, a machine vision-based transverse vibration measurement method of diamond wire is developed in this paper. The approximate edge position of the wire in the image midline is obtained to crop the region of interest in the image by using the maximum continuous same-directional pixel gradient algorithm and thus reduce the computing time. The wire edges in the image are accurately extracted by an adaptive image segmentation method proposed based on the image histogram. According to the surface topography characteristics of diamond wire, a feature extraction algorithm based on the multiple inward line fitting using the least square method is proposed, which can effectively detect the position of the inner diameter boundary of the diamond wire. Accordingly, the equation of the central axis of the wire in the image is obtained to realize the transverse vibration detection of the diamond wire. To conclude, a diamond wire vibration measurement experiment is conducted and the machine vision detection results are compared with the vibration displacement measured by the accelerometer at the same position of the wire end. The results show that the measurement error of the machine vision vibration inspection is generally small for the different types of diamond wires and the different frequencies of the wire transverse vibration, which means that the measurement method proposed in this paper has good accuracy, and applicability, and robustness.

Effect of Protection on Guy Wire Related to Corrosion Defects

Guy wires are a powerful mechanical tool used widely in all industries. Most of the applications are employed in supporting tall structures such as antenna, communication towers, transmission lines, electric poles, and erecting flare stacks on an oil and gas platform or plant. Severe wind events such as tornadoes are the primary failurein transmitting line structure in many places worldwide. So, this research aims to investigate the effect of different types of guy wire on corrosion defects. There are many lay and strand design types in the production of guy wire. The two most common are the 7-wires and 19-wires lay. There are four samples with four conditions: the first sample is not protected with any material, the second is protected by lubrication using WD-40, the third is protected using rubber hose casing, and the last is protected by a combination of both lubrication and rubber hose casing technique. The result shows that the sample protected by a combination of lubrication and rubber hose casing has no corrosion defect.

TIG-cladding of Al-Cu and Al-Cu-Sn alloys on pure Al substrate

A tungsten inert gas (TIG) welding process was utilized successfully to produce a dense and hard cladding layer on a commercial purity Al substrate using two commercial filler wires (L-CuP6 and L-CuSn6). Effect of the type of filler wire, welding frequency, and the type of electrical current (AC or DCEN) on the microstructure, hardness, and the residual stress of the cladding layer were studied using scanning electron microscopy, X-ray diffraction, and a hardness test. The results showed that the L-CuP6 wire produced a homogeneous layer containing Al 2 Cu-Al eutectic in an α-Al matrix. The microstructure of the cladding layer formed with the L-CuSn6 wire also contained Al 2 Cu (θ) primary intermetallic and β-Sn grains. The hardness of the cladding layer was found to depend on the fraction of Al 2 Cu intermetallic formed in the microstructure. Increasing the frequency or using a DCEN instead of AC caused the fraction of Al 2 Cu formed to decrease. These effects were attributed to the decrease in the volume of the weld pool and the inability of the DCEN to remove the oxide film from the Al substrate, respectively.

The Effect of Elastic and Metallic Ligation Methods on the Unloading Forces for Three Different Types of Nickel-Titanium Archwires Inserted Into Metallic Brackets: An In-vitro Study.

One of the unique properties of the nickel-titanium (NiTi) archwires is the release of light continuous forces with a wide range of activation, which is affected by the method of ligating the wire to the bracket. Both elastomeric modules and metallic ligatures are the most common components to ligate the archwire to the bracket. This study aimed to evaluate the effect of elastomeric versus metallic ligatures on the released forces of three types of rectangular 0.016- by 0.022-inch NiTi wires. This investigation evaluated three different situations of ligating the NiTi archwires to metallic brackets. The produced forces by these wires were evaluated using a modified three-point bending test (a universal testing machine: Testometric 350M®, Instron, Lincoln Close, Rochdale, England). A 0.022-inch slot-size premolar bracket was used for this investigation with zero torque and zero angulation (Master Series®, American Orthodontics, Sheboygan, USA). The first situation involved no ligation to the metallic brackets using three types of NiTi wires, whereas the second situation (the elastic ligation) involved the use of colored elastomeric modules with a 0.045-inch inner diameter and a 0.115-inch outer diameter (Color Ligatures®, American Orthodontics, Sheboygan, USA) to ligate the archwire into the metallic bracket's slot. In the third situation (metallic ligation), stainless steel metallic ligatures with a 0.012-inch (Preformed Ligature Wire®, American Orthodontics, Sheboygan, USA) were used to perform the ligation. The employed NiTi wires were 0.016 x 0.022-inch in diameter (American Orthodontics®, Sheboygan, Wisconsin, USA), and they were of three different types: (1)the superplastic wires (NT3-SE®), the thermally activated wires at 25°C (Thermal Ti-D®), and the thermally activated wires at 35°C (Thermal Ti-Lite®). The thermally activated wires at 35°C (Thermal Ti-Lite®) recorded the lowest force levels for the three ligation methods, while the highest result appeared with the superelastic type (NT3-SE®) and the thermally activated type at 25°C (Thermal Ti-D®) which showed a varied force for different ligation methods. Regarding the three different NiTi wires used, the elastic and metallic ligation increased the force levels for the superelastic type (NT3-SE®) over non-ligation by 50% and 110%, respectively, whereas the elastic ligation raised only the forces for the thermal types (Thermal Ti-D®and Thermal Ti-Lite®) by 75% and 22%, respectively. Both thermally activated types (Thermal Ti-D®and Thermal Ti-Lite®) released forces in the elastic ligation method greater than that of the metallic method by 125% and 20%, respectively. The elastic ligation method raised the unloading forces in comparison with the non-ligation for all tested archwires, whereas the metallic ligation method raised the released forces for the superelastic type (NT3-SE®) and decreased those related to the activated types (Thermal Ti-D®, Thermal Ti-Lite®)due to the increased friction and the instability of the crystalline structure. Only the heat-activated type at 35°C (Thermal Ti-Lite®) reflected the unique properties of the NiTi wires in producing light continuous forces with a wide range of activations regardless of the type of ligation.

Mechanical and Metallurgical Characterization of Nickel-Titanium Wire Types for Rotary Endodontic Instrument Manufacture

This study aimed to evaluate and compare the effects of ambient temperature and post-manufacture heat-treatment on the mechanical behavior of nickel-titanium (NiTi) wires. Four types of commercial NiTi variants (Stock NiTi, heat treated "Blue", "Gold", "Superflex", all Dentsply Maillefer, Ballaigues, Switzerland) were stressed in a tensile testing machine in a temperature-controlled water bath at three different temperatures. Stress and strain values were extrapolated from the raw data, and 2-way ANOVA and Tukey's test for multiple comparisons were performed to compare the differences of the mechanical constants. Differential scanning calorimetry (DSC) tests established the martensitic transformation starting (Ms), finishing (Mf) and austenitic (reverse-martensitic) starting (As) and finishing (Af) points. Austenitic modulus of elasticity and transformation stress values increased with temperature for all NiTi groups. The martensitic modulus of elasticity, maximum transformation strain and ultimate tensile stress were not significantly affected by temperature changes. Stock NiTi and Gold wire samples presented with clearly delineated austenitic and martensitic transformations in the DSC experiments. Differences in manufacturing/heat treatment conditions and ambient temperature affect the mechanical behavior of nickel-titanium and may have clinical implications. Further improvements to the experimental setup could be considered to provide more accurate measurements of strain.

Low-velocity impact behavior of SWRH82B steel wires considering different section shapes based on experiments and simulations

SWRH82B steel wires are commonly used in suspended-cable structures, large-span structures, and cable-stayed bridges owing to their light weight, strong bearing capacity, and safe and reliable operation. In this study, the dynamic mechanical performance of SWRH82B steel wires under low-velocity impact was studied experimentally and numerically. A drop-hammer impact test system was adopted for the impact experiments, considering the influence of the specimen diameter, specimen span, indenter shape, and impact position. Two-section steel wires, including circular and Z-shaped wires, were investigated. The experimental results indicated that local denting deformation occurred at the impact position with a lower impact energy, and wire breakage occurred near the position of the clamping device with a larger impact energy. Circular wires were stronger and stiffer than Z-shaped wires of the same diameter because they can provide a higher impact resistance and stronger energy absorption capacity with a regular section shape. The experimental data indicated that the specimen diameter positively affects the impact bearing capacity, providing more flexural rigidity. However, the specimen span negatively influences the dynamic performance of both types of steel wires; a greater increase in peak load was observed when using a cylinder hammer. In addition, a finite element model was established to further analyze the failure modes and discuss a larger range of parameters. Finally, a numerical model of prestressed steel wires was developed using ABAQUS/EXPLICIT, with the results indicating that the prestress force could strengthen the impact resistance of steel wires at a lower level.

An in vitro comparative evaluation of surface roughness characteristics of different orthodontic archwires: An atomic force microscopy study.

Background. The present study evaluated and compared the surface roughness (SR) of five different types of orthodontic archwires made by two different manufacturers. Methods. In this in vitro study, 10 samples of five different archwires comprising of three types of shape memory wires, SmartArch (Ormco), Damon (Ormco), Heat-activated NiTi (HANT) (G&H Orthodontics), Stainless Steel wire (SS) (Ormco), and conventional NiTi (G&H Orthodontics) were examined by atomic force microscopy (AFM). The processing of 3D images was carried out using Gwyddion software, from which the root mean square (rms), the roughness average (Ra), and the maximum height (mh) of the scanned surface profile were documented. The data were analyzed with one-way ANOVA followed by post hoc Tukey tests for intergroup comparisons. Results. The mean SR of SS wires was the least (Ra=8.70±0.17), followed by NiTi wires (10.29±2.00) with a significant difference between them (P<0.05). Among the three shape-memory wires, the HANT wires had the least SR (Ra=22.97±16.56) compared to SmartArch wires (Ra=25.55±3.78) and Damon wires (Ra=25.67±4.54), but the difference was not significant (P>0.05). Conclusion. The SS wires by Ormco had the least SR followed by G&H orthodontics NiTi wires. The three different shape-memory wires tested had no significant difference in SR values.

The measuring systems of the wire tension for the MEG II Drift Chamber by means of the resonant frequency technique

The ultra-low mass cylindrical drift chamber designed for the MEG II experiment is a challenging apparatus made of 1728 ϕ=20μm gold plated tungsten sense wires, 7680 ϕ=40μm and 2496 ϕ=50μm silver plated aluminium field wires. Because of electrostatic stability requirements all the wires have to be stretched at mechanical tensions of ∼25, ∼19 and ∼29g respectively which must be controlled at a level better than 0.5g. This chamber is presently in acquisition, but during its construction ∼100 field wires broke, because of chemical corrosion induced by the atmospheric humidity.On the basis of the experience gained with this chamber we decided to build a new one, equipped with a different type of wires less sensitive to corrosion. The choice of the new wire required a deep inspection of its characteristics and one of the main tools for doing this is a system for measuring the wire tension by means of the resonant frequency technique, which is described in this paper. The system forces the wires to oscillate by applying a sinusoidal signal at a known frequency, and then measures the variation of the capacitance between a wire and a common ground plane as a function of the external signal frequency. We present the details of the measuring system and the results obtained by scanning the mechanical tensions of two samples of MEG II cylindrical drift chamber wires and discuss the possible improvements of the experimental apparatus and of the measuring technique.

Influence of Knitting Structure and Metal Wire Amount on Electromagnetic Shielding Effectiveness of Knitted Fabrics

The aim of this study is to investigate the influence of knitting structure and metal wire amount on the electromagnetic shielding effectiveness (EMSE) of knitted fabrics comparatively. Single jersey, single pique, weft locknit, and cross miss fabrics involving stainless steel or copper wires were produced on a flat knitting machine. A free space measurement technique was used for the EMSE measurements in an anechoic chamber. The variance analysis results of the EMSE values reveal that the effect of knitting structure, metal wire type, metal wire amount, and incident wave frequency is highly significant. It was observed that fabrics with tuck and miss loop structures had higher EMSE values than single jersey fabrics. It was found that single pique fabrics had higher EMSE values than single jersey fabrics that contain twice as much metal wire. It indicates that changing the knitting structure is more effective than changing the metal wire amount.

Comparison of microleakage and shear bond strength of ribbon and twisted wire retainers bonded on human mandibular incisors with two different types of adhesives with and without primer: An in-vitro study

Background and objectivesShear bond strength and microleakage are the success factors of fixed retainers. Recently, primer-free composites were introduced to reduce chair time. The main objectives of this study were to compare the shear bond strength (SBS) and microleakage of GC Ortho ConnectTM Flow (OF) and TransbondTM XT (TXT) with two types of common retainer wires (0.0175-inch twisted wire and 0.028×.0.008-inch ribbon dead soft wire retainers). The secondary objectives of the study were to compare enamel-adhesive interface and wire-adhesive interface microleakages. Materials and methodsThis in vitro study was conducted on 132 human mandibular incisors (96 for bond strength and 36 for microleakage). The teeth were randomly divided into four groups for use of ribbon and twisted wires with OF and TXT adhesives. The bond strength was measured by a universal testing machine. Microleakage was evaluated by the dye penetration test using 0.05% fuchsine. Data were analysed by two-way ANOVA (alpha=0.05). ResultsNo significant difference was noted in bond strength among the four groups (P>0.05). However, the microleakage of OF was significantly higher than that of TXT at both the enamel-adhesive and wire-adhesive interfaces (P<0.001). The microleakage at the wire-adhesive and enamel-adhesive interface was not significantly different in groups 1 and 4 and was significant in group 2 and 3. ConclusionType of adhesive significantly affected the microleakage, and OF resulted in higher microleakage than TXT at both the enamel-adhesive and wire-adhesive interfaces. Type of wire had no significant effect on microleakage. Although OF showed comparable SBS to TXT, its higher microleakage may compromise its successful long-term clinical service.