Wire Matrix Research Articles

Pull-out behaviour of steel and carbon fibers in 3D-printable cement matrices of various compositions

The aim of this study was to investigate some of the factors which affect the fiber–matrix pull-out behaviour and bond strength. 3D-printable cement mixtures with various compositions were used as matrices. The effect of parameters such as type of fiber (steel or carbon), kind of aggregates (sand or limestone powder), and kind of modifier additives (metakaolin or complex nano-sized additive based on SiO2 (CNA)) on fiber–matrix pull-out behaviour were determined. The results demonstrated that the bond strength of a fiber-matrix mainly depends on the fiber type. The bond strength of a “steel wire matrix” was 2–4 times higher than the bond strength of a “carbon fiber matrix”. The fiber–matrix bond strength increased as the conditions for the wetting of a fiber’s surface improved, especially for carbon fiber. Microstructural investigation revealed that the congestion of hydration products in a fiber–matrix interface significantly improved the pull-out behaviour. The use of sand as an aggregate for a cement matrix enhanced the bond strength by 10–15% in “steel wire matrix” systems. The introduction of metakaolin and CNA into a cement matrix increased the bond strength by 15–20% for sand-based and powder-based cement matrices.

Analytic solution for the lightning current induced mutually coupled resistive filament wire model

<abstract><p>When a lightning current flows between the lightning entry and exit points of a structure, the lightning current density varies in different parts of the structure depending on the shape of the structure and material variance. The structure can be discretized into parallel wires, called filament wires, running parallel to the current direction. Furthermore, using the filament wire method, we can calculate the current distribution among the wires. For a structure that has a low resistance material such as aluminum, current distribution can be calculated by considering self-inductance of the wire and mutual-inductance between wires but resistance is not considered. However, in modern aircraft, composite materials are used for parts of the structure because of their strength and weight. These composite materials have high resistance compared to metal, and resistance cannot be ignored. Thus, to solve a system of ordinary differential equations for a filament model, inhomogeneous structure, aperture, and resistance of each wire must be considered to obtain the correct current distribution of each part of the structure. However, the numerical solution of the filament wire model does not reveal the region of convergence and the accuracy of the given mathematical model. It also has high time complexity. This paper presents the analytic solution and stability condition for the mutually coupled resistive filament wire model using eigenvalues of given filament wire matrix model. The stability condition is rigorously calculated and the solution is also consistent with the numerical model.</p></abstract>

Thickness Effects on the Martensite Transformations and Mechanical Properties of Nanocrystalline NiTi Wires.

This paper studied the features of the martensitic transformations and mechanical properties of 40, 60, and 90 µm thick NiTi wires with nanocrystalline B2 structures. It was established that the wires were composites and consisted of a TiNi matrix and a TiO2 + TiNi3 surface layer. Structural methods showed that the wire matrix was formed by grains of up to 20 nm in size. The method of measuring the electrical resistivity during cooling and heating revealed a two-stage nature of the martensitic transformation. Cyclic loading-unloading demonstrated that all the samples exhibited superelasticity effects and completely restored their shape when unloaded from a 4-8% relative strain at room temperature. An increase in mechanical characteristics with respect to the wire thickness was experimentally established. This was due to the change in the composition of the TiNi matrix during drawing.

Simulation of Thermosiphon Reboilers Using Wire Matrix Inserts at Lower Operating Range

Heat transfer enhancement to enlarge the operating range enables a more efficient use of thermosiphon reboilers. For this purpose, the use of wire matrix inserts in thermosiphon reboilers was studied experimentally and via simulation. The boiling of water/glycerol as a wide boiling mixture with an elevated viscosity was investigated at a sub-atmospheric pressure of 0.2 bar abs and a submergence of 110%. With varied driving temperature differences, single-phase reboiler inlet velocities from 0.01 m·s-1 to 0.16 m · s-1 were induced coupled with heat fluxes ranging from 1 kW·m-2 to 22 kW·m-2. By using inserts, the reboiler showed significant improvement of fluid dynamics and thermal performance and could be operated at lower temperature differences. The simulation confirmed the advantageous usage of inserts. However, the heat transfer was underestimated possibly resulting from the neglected subcooled boiling and deficits in the flow boiling model for the wide-boiling mixture at low pressures.

WIRE-MESH CAPACITANCE TOMOGRAPHY FOR TREATMENT PLANNING SYSTEM OF ELECTRO-CAPACITIVE CANCER THERAPY

The wire-mesh capacitance tomography (WMCT) has been applied to visualize 2D of the distribution of electric field intensity in the treatment planning system (TPS) of electro-capacitive cancer therapy (ECCT) using human head model. WMCT is proposed in this study to estimate accurately the distribution of electric field intensity which is the main optimum factors of ECCT in order to compensate the inaccuracy of TPS ECCT simulation. The experimental and simulation studies were conducted with wire-mesh sensor consisted of 8×8 wire matrix of copper in human head model using two type of helmet ECCT. The result of electric field value at the intersection wire-mesh have been compared between experimental studies and simulation studies. The electric field average value resulted from ECCT helmet-1 is higher than ECCT helmet-2. The average electric field generated by the ECCT helmet-1 is 1585.72 V/m in an air medium, 97.43 V/m in grey matter and 80.58 V/m in the cancer. While the average electric field generated by the ECCT helmet-2 is 1413.28 V/m in an air medium, 64.20 V/m in grey matter and 52.65 V/m in the cancer. ECCT helmet-1 and helmet-2 result the different of electric field distribution pattern. ECCT helmet-1 is more optimal for used to patient has cancer position in the right and bottom, while ECCT helmet-2 is more optimal for used to patient has cancer position in the top and bottom.

Improvement of thermal conductivity by adding tungsten and/or copper wire in F82H

ABSTRACT The F82H, which is one of reduced activation ferritic/martensitic steels, is a strong candidate structure material for fusion reactor because of its satisfactory mechanical property and high swelling resistance in the operating temperature range. One disadvantage of F82H would be its low thermal conductivity as a structural material for divertor. In this study, we have fabricated several F82H-based composite materials by the spark plasma sintering to improve its thermal conductivity by adding tungsten and/or copper wires. F82H-20 vol.% W and F82H-10 vol.% W-10 vol.% Cu composites included reaction layers at the interface between tungsten wire and F82H matrix, resulting in the decrease in ductility and tensile strength because of the formation of tungsten carbide. On the other hand, F82H-20 vol.% Cu composite, sintered for 120 min at 1000°C, included no reaction layers and showed the highest thermal conductivity with a high relative density. Furthermore, it showed a great tensile property, which is comparable to that of the original F82H.

Use of Wire Matrix Inserts in Thermosiphon Reboilers in the Lower Operating Range

AbstractTurbulators are applied to increase the thermal efficiency of heat transfer units. The additional pressure drop can be challenging for the self‐circulation of thermosiphon reboilers. Thus, the effects of hiTRAN®‐wire matrix inserts for the boiling of water and a water/glycerol mixture were investigated herein, using the performance of a thermosiphon reboiler with plain tubes as a reference. The reboiler was operated at sub‐atmospheric pressures, small driving temperature differences, and under flooded conditions. Favorable and unfavorable operating conditions for using inserts were specified. Especially for the water/glycerol mixture, significant improvements of self‐circulation and heat transfer up to six times compared to the plain tube reference were observed, allowing an operation of thermosiphon reboilers at smaller driving temperature differences under sub‐atmospheric pressures.

Influence of porous inserts on flow boiling heat transfer in horizontal tubes

In this paper we want to assess the mechanisms by which metal porous inserts influence flow boiling heat transfer in horizontal tubes. For this purpose, measurement data of the local and circumferentially averaged heat transfer coefficient of CO2 flow boiling in horizontal tubes with two different porous inserts are presented. As inserts, different sponges (open-cell network structures) and a wire matrix element are chosen and compared with each other. Different operating conditions were investigated. The mass flux was varied in a range from 25 kg m−2 s−1 to 190 kg m−2 s−1 and the vapor quality from 10% to 100%. Saturation pressures of 12 bar, 19 bar and 26.5 bar and average heat fluxes up to 65 kW m−2 were realized. By comparing the local heat transfer coefficient with empty tube data, wetting and convective heat transfer can be identified as the main influencing factors. Thus, we can obtain guidelines for the development of a model to describe the heat transfer coefficient of two-phase flow in porous inserts. A model derived in this way describes the measurement data of flow boiling of CO2 in horizontal tubes with inserts with a high degree of accuracy. The model is based on established sub-models without any additional fitting parameter. More than 90% of all measured data are predicted with less than 30% deviation

Intensification of thermo-hydraulic and exergetic performance by wire matrix and wavy tape: An experimental study

The present study contemplates diverse flow range (1500 < Re < 15,000) to deduce the thermo-hydraulic and exergy performance of the twisted tape, wire matrix and wavy tape inserts (with three variants each) involving water as the heat transfer fluid in the 26.5 mm diameter tube. The testing of all the inserts under an identical operating condition (heat flux of 6 kW/m2) ensured realistic energy parameters viz. wall temperature, heat transfer coefficient, exergy destruction and second law efficiency. In comparison, wavy tape proved to be the most cost-effective and lucid design insert which can be incorporated in compact heat exchangers as the thermal advantage is highest as indicated by the performance evaluation criterion – I. Even the lowest exergy destruction complemented by highest second law efficiency made it perfect for the waste heat recovery process. Further, wire matrix being the convoluted design, gave maximum thermo-hydraulic rating (performance evaluation criterion – III) to suggest it in the tubular heat exchangers. Hence based on the thermal or thermo-hydraulic accountability, widely used twisted tape can be replaced by wavy tape or wire matrix. To explore its application further, Nu and f correlations have also been developed and validated.

Thermo-hydraulic and exergy analysis of parabolic trough collector with wire matrix turbulator: an experimental investigation

Thermo-hydraulic and exergy analysis of parabolic trough collector with wire matrix turbulator: an experimental investigation

Thermo-hydraulic and exergy analysis of parabolic trough collector with wire matrix turbulator: an experimental investigation

The parabolic trough collector (PTC) is being researched extensively due to its inherent characteristics. However, the majority of studies are numerical as its receiver is subjected to non-uniform ...

Enhancing deteriorated heat transfer of supercritical nitrogen in a vertical tube with wire matrix insert

In this study, hiTRANTM wire matrix tube insert was used to improve the heat transfer deterioration of supercritical nitrogen (N2) in a heated tube caused by the effects of thermo-physical property variations and buoyancy force. Heat transfer experiments were carried out with N2 flowing upwardly in a vertical circular tube with and without the wire matrix insert under a sequence of experimental conditions including pressures of 35 and 40 bar, mass flow rate of 27.6 and 41.3 g/min and constant heat flux conditions at 6.8, 8.0 and 9.3 kW/m2, respectively. Experimental results show that N2 exhibits similar heat transfer behavior when transiting across the pseudo-critical point as other fluids such as water and CO2. Due to the addition of the wire matrix insert, that intensified the overall fluid mixing in the test tube, the heat transfer performance of N2 was enhanced by more than 42% and up to 2.35 times while the pressure drop increase was negligible compared to the system inlet pressure. Moreover, it has been demonstrated that there might exist an optimum combination of experimental conditions leading to the maximum performance of the wire matrix insert. Furthermore, as the results show, with the Dittus-Boelter correlation and correlations for water and CO2 falling short of fitting the heat transfer data of N2, a heat transfer correlation, exclusively for N2 going through the pseudo-critical point is needed. The findings in this study also reveal that both supercritical N2 internal flow heat transfer and the use of wire matrix insert to enhance the deteriorated heat transfer of supercritical fluids are promising topics and require more significant attentions in future studies.

Trade-off between wire matrix and twisted tape: SOLTRACE® based indoor study of parabolic trough collector

Heat transfer augmentation using turbulators in PTC is well known. However, based on the methodology its thermo-hydraulic rating can vary. In the present experimental study, variations of wire matrix and twisted tape have been used to analyse the thermo-hydraulic behavior of the PTC by referring two approaches viz. thermo-hydraulic efficiency and performance evaluation criterion. An innovative method comprising, analytical model-SOLTRACE®- differential resistance heating is incorporated to simulate the highly non-uniform solar irradiance over the receiver in an indoor test rig. Under the same operating condition, thermo-hydraulic efficiency of medium dense wire matrix is maximum whereas twisted tape of twist ratio 3.37 yields better result as per performance evaluation criterion. However, thermo-hydraulic efficiency based analysis is recommended due to the role of realistic pumping power. Further, variation in energy parameters viz. thermal efficiency, pumping power, Nusselt number and their effect on receiver length have been analyzed. The trade-off between two inserts is also discussed with respect to operating condition.

Study of electrical fatigue test in gold-coated siliver-4 wt.% palladium bonding wire

Present study investigates the effects of the electrical fatigue test on the microstructures, electrical properties and elemental distribution of gold (Au)-coated Ag-4Pd (ACA4P) alloy wire. The electrical fatigue test is an important method for estimating the reliability of electronic devices to cyclic thermal stress caused by bias-induced Joule heat. In the bias test, the thermal diffusion behavior of Au atoms on the wire surface was more intense with increasing current density. The Au atoms diffused along the grain boundary of the wire and finally distributed throughout the wire matrix. In the bias fatigue test, the electrical resistances of the wire and ball bond decreased, and then increased as the bias cycle increased to 6000 cycles. An increase in grain size of the wire and ball bonded wires by bias-induced thermal energy caused their electrical resistances to decrease. Poisson's effect caused the diameter of the wire to decrease, and thus increased the resistance of the wire. The growth of Ag2Al intermetallic compounds (IMCs) at the bonding interface was responsible for the increase in the resistance of the ball bonded wire.

Synovial Lipomatosis with Chondroblastoma in an 8-year-old Female: A Previously Unreported Entity.

Introduction:Synovial lipomatosis is a rare disease entity and a very small number of cases have been reported so far. It is characterized by villous proliferation of the synovium with expansion by mature adipose tissue. The etiology is unclear, thought cases can be seen secondary to injury, inflammation, chronic degenerative changes and neoplasms. Etiopathogenesis is still unclear, however is seen secondary to injury, inflammation, chronic degenerative conditions and neoplasms.Case Report:An 8-year-old female child presented with pain and swelling in the left knee. Radiological examination suggested of a lytic lesion in upper tibia along with reactive synovial thickening. The lytic lesion was excised and an incisional biopsy was taken from the hyperplastic synovium. Histopathological examination of the synovial tissue showed villi-like structures with mature adipose tissue expanding the synovial lining along with the presence of mild chronic inflammatory cell infiltrate. The lytic lesion showed a cartilaginous tumor comprising mineralized chicken wire matrix surrounding the chondroblasts. A final diagnosis of synovial lipomatosis with chondroblastoma was made on histopathological examination.Conclusion:This may be the first case report in medical literature of synovial lipomatosis coexisting with chondroblastoma in an adolescent girl. It also highlights the need for its increased awareness among young radiologists and pathologists so that an early diagnosis directs correct management and prevents further joint morbidity.

Experimental Augmentation of Heat Transfer in a Shell and Tube Heat Exchanger using Twisted Tape with baffles and hiTrain Wire Matrix Inserts – A Comparative Study

Heat transfer, a mere process of exchange of heat due to a temperature gradient, plays a vital role in industries and domestic applications. Among all the heat exchangers, Shell and Tube Exchanger are used predominantly due to their compact and robust design. For a given design to increase the heat transfer characteristics needs a research investigation. Among all augmentation techniques, a passive method found widely used as it avoids mechanical modification of the existing heat exchanger and addresses only on flow geometry. Twisted tape inserts are extensively used to change the flow geometry of fluid on the tube side. The present research work intended on utilising twisted tape, twisted tape with baffles and hiTrain wire matrix inserts. Experimental investigation reveals that inserts efficiently disturb the tube side fluid flow, in turn, increases pressure drop which increases the fluid wall shear and hence enhances the substantial increase in tube side heat transfer rate. At lower Reynolds number twisted tape with baffles has comparatively higher heat transfer coefficient, and at higher Reynolds, number hiTrain wire has comparatively higher heat transfer coefficient. Friction factor decreases linearly from twisted tape with baffles to hiTrain wire matrix as Reynolds number increases.

Computational homogenization of the elastic and thermal properties of superconducting composite MgB2 wire

Magnetic Resonance Imaging (MRI) background magnets are made from superconducting composite wires that are a metal matrix composite (MMC). Thermal and mechanical properties of the specific wire matrix must be known to optimize the wire configuration for MRI magnet designs. Computational analysis techniques based on numerical homogenization may provide an accurate characterization of a multifilament MMC wire and can reduce the expenses and time required for experimental tests. Recent developments in magnesium diboride (MgB2) superconducting wire has demonstrated their feasibility in a liquid helium (LHe) free conduction-cooled MRI magnet. Computational analysis of an entire superconducting magnet design requires the elastic and thermal properties of these wires. In this work, the temperature dependent elastic modulus, Poisson’s ratio, thermal expansion coefficients, thermal conductivity, and specific heat are estimated using Finite Element Analysis (FEA) and compared to analytical approaches. The orthotropic elastic and thermal properties of four different superconducting composite wire configurations are evaluated. The experimental thermal conductivity and specific heat at room temperature agree well with its corresponding computational results. FEA based computational homogenization has been demonstrated as an acceptable method to estimate the required material properties of the MMC superconducting wire for magnet analysis of MRI manufacturing and operation.

Modelling and parametric study of an efficient Alpha type Stirling engine performance based on 3D CFD analysis

As an externally heated engine the Stirling engine has the advantage of being able to efficiently exploit various waste heat sources. Computational fluid dynamic simulation (CFD) for the thermodynamic performance of such engines can provide a powerful tool to predict and improve the design and performance. Despite the advantages of alpha type Stirling engines, there has been very limited published work regarding the use of CFD modelling to improve its performance. This paper, proposed a new methodology combining the thermodynamic model with 3D CFD analysis to investigate the performance of a V-Alpha Type Stirling engine under various operating conditions and design parameters. The thermodynamic model of an alpha type Stirling engine has been developed using non-ideal adiabatic analysis and validated against experimental measurements of the engine prototype. A 3D CFD model was then developed and the results, compared to the those of the thermodynamic model, showed good agreement in predicting the indicated power.The CFD model was used to carry out a parametric study to investigate the effects of various design parameters and operating conditions such as, regenerator porosity, charge pressure, matrix wire diameter, dead volume and hot/cold ends temperatures on the engine performance in terms of power output through predicting the PV diagram of the engine. Results showed that maximum power can be achieved by increasing the porosity up to 80% and the wire matrix diameter to 0.02mm at a temperature of the hot and cold sides at 600°C and 20°C respectively. Further decreasing of the cold end temperature to −20°C can produce 162W. For the heater and the cooler volumes, it was found that a height of 140mm produced the highest engine power output of 170W. This work highlights the potential of using CFD modelling to improve the design parameters and operating conditions to enhance the performance of alpha type Stirling engines.

姿勢解析のための網型圧力センサアレイ

In recent years, studies on posture analysis have been actively conducted in order to solve health problems related to posture. In this paper, we propose a net-type pressure sensor array using wires. The pressure distribution is estimated by the wire tension with pulleys and force sensors. By adopting a matrix-like structure, it is possible to configure with fewer sensors than the resolution of the pressure distribution. Furthermore, the“Center Of Pressure: COP”position, which is closely related to the posture, can be estimated by measuring each wire matrix. In this paper, the estimation accuracy of COP is verified by experiments and the estimation accuracy is improved by using Gaussian filter.

姿勢解析のための網型圧力センサアレイ

In recent years, studies on posture analysis have been actively conducted in order to solve health problems related to posture. In this paper, we propose a net-type pressure sensor array using wires. The pressure distribution is estimated by the wire tension with pulleys and force sensors. By adopting a matrix-like structure, it is possible to configure with fewer sensors than the resolution of the pressure distribution. Furthermore, the “Center Of Pressure: COP” position, which is closely related to the posture, can be estimated by measuring each wire matrix. In this paper, the estimation accuracy of COP is verified by experiments and the estimation accuracy is improved by using Gaussian filter.