Wire Spacing Research Articles

High-performance shim coil design and engineering optimization for use in an extremely high field superconducting magnet

The extremely high field has significant advantages in imaging quality and analyzing the fine structure of substances. However, its excellent performance requires the support of a higher-performance shim technique. In this paper, a novel structural design pattern of the shim coil for a 27 T extremely high field superconducting magnet is proposed. According to the contours of the stream function, we designed and optimized the shim coil pattern and engineering processing. The novel design was realized by using the contours as the centerline, and the wire spacing was controlled at 1 mm. The performance of the novel pattern was compared with those of alternative winding schemes. The results indicate that the novel design can improve coil performance, achieving higher fidelity and lower power dissipation.

Numerical study on flow-induced vibration of LBE-cooled wire-wrapped rod bundle

Flow-induced vibration (FIV) characteristics of LBE-cooled wire-wrapped rod bundle are crucial to the wire-to-cladding fretting. In the present study, numerical simulation on FIV of wire-wrapped rod bundle in LBE flow was performed using a fluid–structure interaction methodology based on the coupling between fluid and solid domains. The effects of geometry parameters on the FIV of wire-wrapped single rod and rod bundle were obtained. The results show that the circumferential force of coolant on the single fuel rod was uneven, which made the fuel rod undergo elliptical and off-axis periodic vibration. The variations of structure parameters of wire spacers had weak effects on the vibration of the single rod, while significant effects on the vibration trajectory of rod bundle. The vibration characteristics of border rods were more sensitive to the variations of transverse flow, while the center fuel rods were more sensitive to the difference in support constraint.

Wireless‐SpaceWire bridge for intrasatellite transmissions

SummaryThe scope of this paper is to present the proof‐of‐concept and functional verification of a Wireless‐SpaceWire bridge (High‐Throughput Wireless‐SpaceWire Bridge for Intra‐Satellite Transmissions [HiSAT] bridge) designed to replace the wired SpaceWire (SpW) connections for intraspacecraft communications. To provide proper data handling and conversion, the proposed solution implements two main components: (1) the SpW Converter, which provides the SpW interface, and (2) the Wireless Converter, which provides the multiantenna radio frequency (RF) front‐end. High‐end research infrastructure is used in the solution implementation. STAR‐Dundee SpW products emulate real spacecraft instrumentation and implement the SpW links and interfaces. Xilinx FPGA ZCU102 boards are used for the implementation of the hardware/software communication stack of the SpW Converter. A comprehensive National Instruments USRP Software Defined Radio platform is used to implement the Wireless Converter. End‐to‐end laboratory tests are run to evaluate the performance of the proposed solution in terms of average end‐to‐end delay, average data rate, and packet success rate and to assess the technology readiness. The results demonstrate that the HiSAT bridge is TRL4 and that the technological approach (i.e., using FPGAs and OFDM transmissions) can successfully replace an on‐board intraspacecraft SpW link.

Study on mechanical properties of corroded concrete columns strengthened with SMA wires.

Ocean crossing bridges suffer from seawater corrosion all year round and their mechanical properties will be substantially diminished. In order to enhance the mechanical properties of reinforced concrete columns corroded by seawater, SMA wire is used to restrain the reinforced concrete columns corroded by seawater to study their mechanical properties. 14 specimens were produced through the test, and the natural seawater corrosion was simulated by preparing a certain concentration of synthetic seawater. The mechanical properties of SMA strengthened specimens and unreinforced specimens are compared and analyzed, including failure mode, hysteresis curve, bearing capacity, ductility, stiffness and energy dissipation; the effects of different synthetic seawater corrosion concentrations on the mechanical properties of reinforced concrete columns are discussed. The results show that the bearing capacity and stiffness of reinforced concrete columns subjected to synthetic seawater corrosion are substantially diminished than those of uncorroded specimens, and the bearing capacity of specimens decreases more with the increase of synthetic seawater corrosion concentration; synthetic seawater corrosion has obscure effect on the ductility and energy dissipation performance of the specimens. The mechanical properties of the corroded specimens strengthened with SMA wire have been substantially enhanced, particularly the energy dissipation performance and bearing capacity have been notably enhanced, and the ductility and stiffness have also been somewhat enhanced. At the same time, based on the test, the finite element model is created according to the test specimen, while the accuracy of the model is verified, and the effects of the spacing and diameter of SMA wire, the strength of concrete and the thickness of protective layer on the mechanical properties of the specimen are analyzed.

SpaceART SpaceWire Sniffer for Link Monitoring: A Complete Communication Analysis in a Time-Constrained Test Scenario.

The on-board communication standard adopted in current generation space missions of the European Space Agency, and many other agencies as well, is SpaceWire (SpW). In a SpW network, data are exchanged as well-formed packets, whose structure offers low packet overhead and allows developers to tailor their implementation for SpW applications. The development of SpW-compliant devices requires a specific set of test instruments, namely Electrical Ground Support Equipment (EGSE), to verify the correct functionality of SpW units under test. An example of a SpW EGSE is the SpaceART EGSE Emulator, an EGSE for generation and processing of SpW packets for a time-constrained use-case scenario. This EGSE has been developed to address a mission-related SpW communication between a device and an Instrument Control Unit (ICU). It has allowed the generation and processing of specific SpW packets, which cannot be provided by the mostly used general-purpose SpW EGSEs. In this scope, the SpaceART SpW Sniffer, a SpW link analyser for unobtrusive monitoring of SpW link, has been employed to run a comprehensive set of tests and provide further information on the considered scenario. The SpaceART EGSE Emulator-ICU communication has been thoroughly tested through the SpaceART SpW Sniffer, unobtrusively analysing the exchanged data and allowing to assess the compliance with the defined time constraints from an external point of view. The use of the Sniffer has been crucial for testing the on-board communication, providing important support for the success of the mission employing the tested ICU.

SpaceWire-to-UWB Wireless Interface Units for Intra-spacecraft Communication Links.

In the context of the Eu:CROPIS mission requirements, this paper aims to test and validate an intra-spacecraft wireless transmission carried between two SpW-to-UWB Wireless Interface Units (WIUs). The WIUs are designed to replace the on-board SpaceWire (SpW) connections of a spacecraft network. The novelty of this solution resides in prototyping and testing proprietary TRL6 WIUs for the implementation of both PDHU and CDHU units, which constitute a spacecraft network. The validation test scenarios employed in this paper were designed under the Eu:CROPIS mission system requirements as defined by the WiSAT-3 European Space Agency (ESA)-funded project. The SpW-to-UWB WIUs run a custom-built ISA100 over an IEEE 802.15.4 UWB PHY layer communication stack. The WIUs are evaluated based on four mission-specific performance test scenarios: (1) the link setup test, (2) the end-to-end delay test, (3) the maximum data rate test and (4) the housekeeping test. The validation test scenarios of the WIUs are carried out with the use of STAR-Dundee SpW-capable equipment. The test results demonstrate the reliability of the deployed SpW-to-UWB WIUs devices for UWB wireless communications carried out within a space shuttle. The SpW data were successfully transmitted across the intra-spacecraft wireless network in all experimental tests. The technology can be considered to be at the maturity level TRL6 (functionality demonstrated in relevant environment) for LEO missions.

Transformer High-Voltage Primary Coil Quality Detection Method Based on Machine Vision

Aiming at the problems of low efficiency and low accuracy in manual detection of winding angle and wire spacing during automatic winding of high-voltage primary coils of transmission and distribution transformers, a detection scheme using machine vision is proposed. Firstly, the coil image is acquired by the industrial camera, the detection region is segmented, and the ROI (region of interest) image is pre-processed. For winding angle detection, we propose a slicing method for image graying to reduce the interference caused by uneven light irradiation. The gray image is converted to a binary image, and wire skeleton extraction is performed; the skeleton is identified using the Hough transform for feature straight lines, and the winding angle is then calculated. For wire spacing detection, we propose an intersection of the perpendicular lines method, which extracts edge coordinates using contour images and performs endpoint pixel expansion and shape classification. Use the intersection of the vertical lines to determine the centroid coordinates of the wire outline, calculate the pixel distance of the adjacent centroid, and obtain the wire spacing by combining pixel calibration. Comparison experiments have shown that the solution has a high detection accuracy (0.01 mm), and the error of the integrated detection results is not higher than 10%, which enables the real-time detection of coil winding status and corrects the winding process according to the visual real-time detection result to improve the finished product quality of coils.

Structure optimization of non-magnetic electric heating film for spin exchange relaxation free magnetometer

Spin exchange relaxation free (SERF) atomic magnetometer is one of the most sensitive magnetometers. High temperature and a non-magnetic environment are two key conditions to achieve ultra-high sensitivity. In this paper, a non-magnetic heating film with magnetic field self-suppression is optimized by the genetic algorithm method. Four structural parameters of the non-magnetic heating film including the wire spacing, wire width, wire thickness, and layer distance are optimized to minimize the magnetic field in the heated space. The simulation result based on the finite element analysis method shows that the magnetic field and the temperature field produced by a pair of heating films at the vapour cell are uniform. Finally, the magnetic field experiment proved that when the current is 10 ​mA, the magnetic field is 3.0520 ​nT. The temperature control experiment indicates that the temperature could be stabilized at 180 ​± ​0.2 ​°C. This study is significant for electric heating with a lower magnetic field and contributes to further improving the performance of atomic sensors.

Sensitivity analysis and practical application of an automatic snow-melting membrane roof

In recent decades, numerous membrane structures have been built in the cold regions of China. Nevertheless, uneven snow distribution and snow sliding from the edge of roofs cause frequent collapsing, which threatens people's lives and properties. To prevent the collapsing of membrane structures, we present an automatic snow-melting membrane roof based on an electrical–thermal system (ASMR-ETS) in this paper. ASMR-ETS is environmentally friendly, clean, and can be used for eliminating snow that accumulates on membrane roofs. The most important task in designing ASMR-ETS is the determination of its feasibility. A thermal simulation method for the snow-melting process is described in this paper. The surface temperature was obtained using the commercial software ABAQUS. The applicability and rationality of the thermal simulation were verified via snow-melting experiments. The heating wire spacing and heating wire power were set as heating wire parameters. The wind velocity, solar irradiation, ambient temperature, and snow thickness were selected to be the climatic conditions. The surface temperature of ASMR-ETS was simulated, and the snow-melting performance (snow-free area ratio and coefficient of variation of temperature) was analyzed for different heating wire parameters and climatic conditions. According to the simulation results, increasing the wind velocity and snow thickness decreases the snow-free area ratio and improves the coefficient of variation of temperature, whereas solar irradiation and ambient temperature showed an opposite effect. Furthermore, the snow-melting performance of the membrane structure was studied, and different layout schemes of the heating wire were considered. The results show that ASMR-ETS is practical and can therefore be used to clear snow on membrane structures.

Feasibility of a snow-melting membrane roof with an electrical–thermal system and prediction of its performance

Snow removal from membrane structures used for roofing is a critical activity to effectively avoid collapse accidents caused by non-uniform snow distribution. Electrical–thermal systems that combine electrical with thermal techniques are proposed as a substitute for chemical and mechanical snow removal methods. These systems overcome the problems of conventional chemical-based snow- melting in construction material corrosion and environmental pollution. The aims of this study are to analyze the performance of an automatic snow-melting membrane roof utilizing an electrical–thermal system with heating wires, determine the suitable heating wire parameters and climatic conditions based on the snow-melting performance, and evaluate the system using experimental data. The findings indicate that a copper–nickel alloy heating wire can provide a stable heat source and is suitable for electrical–thermal systems. The surface temperature reached a stable point at 38 °C after 240 min of heating using electrical energy. The recommended heating wire parameters were identified based on the snow-melting performance and energy consumption. The optimal heating wire spacing is 7.5 cm and the most energy-efficient heating wire power is 250 W/m2. The automatic snow-melting membrane roof is always free of snow if snow melting is started at the instant when the snow thickness is less than 20 mm and the solar irradiance is in the range of 100–250 W/m2. The ambient temperature contributes minimally to the snow-melting performance. Finally, artificial neural network (ANN) and multiple linear regression (MLR) models were built to predict the snow-melting performance using the aforementioned parameters as inputs. The ANN model can predict and evaluate the snow-melting performance trend more accurately than the MLR model. The results indicate the possibility for large-scale practical engineering applications of electrical–thermal systems for snow removal.

Study on the effects from spacer wires on coolant flow within a CiADS fuel assembly

Spacer wires are frequently applied as the positioning components of fuel rods in lead-based fast reactors. It is extremely important to carry out the research of the impacts from spacer wires on coolant flow within fuel assemblies, and therefore the safety performances of reactor core. In this paper, the open source CFD calculation software OpenFOAM was adopted to perform the refined numerical simulation on the rod bundle of the fuel assembly in CiADS. The results show that spacer wires will increase the pressure drop along the rod bundle section of the fuel assembly. The empirical formula of Remhe and Novendstern can better evaluate the pressure drop along the rod bundle section of the fuel assembly in CiADS. The mixing effect of spacer wires may enhance the LBE flow velocity and heat transfer coefficiency. The winding pattern has a noticeable effect on the temperature distribution at the assembly outlet. When the winding angle of spacer wires is set at 30°, the temperature distribution at the outlet of the assembly will be more uniform.

Influence of wire spacing and plate spacing on electrostatic precipitation of nanoparticles: An approach involving electrostatic shielding and diffusion charging

Electrostatic precipitation is a process widely used as gas cleaning device, to removal particles from gas flows. However, in a conventional and well-sized precipitator, the collection efficiency decreases for ultrafine particles, making it difficult to employ this equipment for controlling nanoparticle pollution. This paper investigates the influence of plate spacing (4 and 6.5 cm) and wire spacing (4, 6, and 12 cm) on the electric current and nanoparticle collection efficiency, considering the effect of diffusion charging and electrostatic shielding. Two laboratory-scale dry wire-plate electrostatic precipitators with different plate spacings were tested for the collection of nanoparticles (6.15–241.4 nm) at three air velocities (1.9, 2.9, and 3.9 cm/s). The results demonstrated the effectiveness of the equipment in removing nanoparticles (99.9%) under the highest electric fields. Higher values of the wire spacing led to increases in the current and the collection efficiency. This was associated with reduced electrostatic shielding, which is more evident in smaller ducts with a higher density of field lines. It is expected that the findings should improve knowledge on electrostatic precipitation of nanoparticles, enabling optimization of collection efficiency by considering the effects of geometric parameters.

Study on axial compression bearing capacity of in-sulated sandwich concrete wall with embedded columns

An insulated sandwich concrete wall with embedded columns (ISCW-EC) is proposed by introducing horizontal reinforcements and cold formed steel embedded columns to the traditional insulated sandwich concrete wall. Axial compression load tests were performed on two full-scale specimens with different horizontal reinforcement spacings to investigate the failure mode of ISCW-EC. The failure patterns of both specimens are the same: splitting cracks present at the bottom of specimen and local buckling occurs at the bottom of the embedded column. The test results show that the specimen with smaller horizontal reinforcement spacing has smaller cracking load, lower secant stiffness, lower ductility and higher compression bearing capacity. Based on the test results, refined finite element models were established to perform a multi-parameter analysis in which the influences of horizontal reinforcement spacing, embedded column spacing, concrete strength and steel wire diameter are studied. The multi-parameter analysis results show that the increase of concrete strength and wire diameter improve the axial compression bearing capacity while the increase of the horizontal reinforcement spacing and embedded column spacing reduce it. Finally, the calculation formula of axial compression capacity of ISCW-EC is put forward based on both test and finite element analysis results.

Monitoring of Surgical Wounds with Purely Textile, Measuring Wound Pads—III: Detection of Bleeding or Seroma Discharge by the Measurement of Wound Weeping

To enable stating a final common sensor design of purely textile, measuring wound pads for the monitoring of surgically provided wounds with regard to tissue temperature, moisture release and stretching (as indicators for the most prominent wound healing disruptions bacterial inflammation, bleeding/seroma discharge, and haematoma/seroma formation), the aim of this investigation was to identify and quantify possible variables practically affecting the detection of water in a systematic study. The textile sensors comprise insulated electrical wires stitched onto a textile backing and parallel wires form a plane sensor structure whose electrical capacitance is increased by water (contained in blood or lymph) in the textiles. Only parallel sensor wires forming double meanders were examined because this structure enables all the parameters of interest to be measured. Surprisingly the results are complex, neither simple nor consistent. The change in electrical capacitance (measuring signal) upon the standardized addition of water was not additive, i.e., it was not found to be correlated to the moistened area of the sensor array, but inversely correlated to the diameter of the sensor wire, mildly pronounced in connection with smaller stitching spacing (stitching loops along the sensor wires). The measuring signal reached a maximum with medium sensor wire spacings and pronounced with a smaller stitching spacing. Without exception, the measuring signal was systematically higher in connection with smaller (compared with larger) stitching spacings. The results presented indicate that the optimization of the capacitive textile sensors cannot be calculated but must instead be carried out empirically.

Effect of diffusion on the peak value of energy loss observed in a LArTPC

Liquid Argon Time Projection Chamber (LArTPC) detectors observe ionization electrons to measure charged particle trajectories and energy. In a LArTPC, the long time (∼ms) between when the ionization is produced and when it is collected means that diffusion can smear the charge by an amount comparable to the spatial resolution of the detector, given by the spacing between charge sensing channels (∼mm). This smearing has an impact on the distribution of energy losses measured by each channel. In particular, the smearing increases the length of the charged particle trajectory observed by each channel, and therefore the most-probable-value (MPV) of particle energy loss recorded by that channel. We find, for example, that this effect shifts the MPV dE/dx of a muon with an energy of 1 GeV by ∼4% for a 2 ms drift time and 4.7 mm wire spacing, as in the DUNE-FD LArTPC. This has implications for the energy-scale calibration and electron lifetime measurements in a LArTPC, which both use the MPV of the muon energy loss distribution as a “standard candle”. The impact of diffusion on these calibrations is assessed.

Study on Flexural Behaviour of Ferrocement Composites Reinforced with Polypropylene Warp Knitted Fabric.

Ferrocement is a cost-effective construction material used in the low-cost constructions. It is produced with the combination of cement mortar with closely spaced wire mesh known as chicken wire mesh. Ferrocement process eliminates coarse aggregates when compared to reinforced concrete thus makes the process simple. This paper deals with the influence of various characteristics of warp knitted fabric on the flexural properties of ferrocement composites. Ferrocement composites have a wide range of applications in the construction industry and it has some limitations due to the durability issues. Among the various durability issues, corrosion is one of the main issues to be addressed to enhance the long-term service life of the ferrocement composites. The idea of using non-metallic mesh to eliminate the corrosion problem is discussed in this paper. In this experiment, warp knitted fabric reinforced ferrocement composites were produced using polypropylene warp knitted fabrics. This paper deals with the flexural properties of ferrocement composites made of warp knitted fabric coated with expoxy. This paper deals with the flexural properties of ferrocement composites made of warp knitted fabric coated with expoxy. These composites were analyzed for their flexural strength, energy absorption and ductile property. The variables in the experiment are filament thickness, warp knitted structure and number of layers in the composites. Experimental results proved that the replacement of chicken mesh wire by warp knitted fabrics has an impact in the flexural properties of the composites and the effect of variables in the experiment set up has been analyzed. There is an imporvement of 200% is observed in the first crack load and 120% improvement in the ultimate load of the warp knit fabric reinforced composite compared to control sample. Experimental results proved that there is an increase in flexural strength of ferrocement composites made up with warp knitted fabrics. Microstructure studies like SEM and EDX on ferrocement laminates confirmed good bonding between the mortar mix and warp knitted fabrics.

Heat transfer enhancement of spray cooling by copper micromesh surface

Spray cooling has become one of the most promising heat dissipation technologies for thermal management of super high heat flux. The traditional strategies to enhance spray cooling have mainly strengthened the forced convection at high spray flow rate, or extended the triple line area for evaporation by micro/nano structure, which is challenging in promoting heat transfer efficiency. In this work, multi-layer copper micromesh is applied to increase the heat transfer proportion of liquid film boiling in spray cooling, which improves onset of nucleate boiling (ONB), and enhances the critical heat flux (CHF) and heat transfer coefficient (HTC) simultaneously. Synergistic effects of micromesh structures (including thickness and spacing width) and spray flow rate on liquid supply and bubble escape are demonstrated: high micromesh thickness, small wire spacing width, and large spray flow rate increasing liquid supply but impeding bubble escape. It is shown that the surface temperature at ONB on multi-layer micromesh has decreased by 16 °C approximately, and #100 4-layer micromesh sample exhibits the best heat transfer performance at 1.14 ml/s with CHF of 605.2 W/cm2 and maximum HTC of 71.45 kW/(m2·K), which is enhanced by 127.3% and 175.7% compared with flat surface, respectively.

Development Technology of Special Tool for Replacing Double-split Wire Spacer Rod

Development Technology of Special Tool for Replacing Double-split Wire Spacer Rod

Removal of Magnetic Fine Particles From Carbon Black Powder by High Gradient Magnetic Separation Under Dry Condition

Removal of magnetic fine particles from carbon-black powder by utilizing the high gradient magnetic separation with a newly developed magnetic wire filter under dry condition was studied. The developed magnetic filtering system has magnetic thin wires arranged in one direction with a regular interval and the rotating layered structure perpendicular to the magnetic field direction. This makes it possible to capture the magnetic fine particles without clogging the filter under dry condition. The capture rate in the magnetic filter was investigated in detail by both magnetic separation experiments and three-dimensional FEM particle trajectory simulations. With reducing both the magnetic wire size and the wire spacing, and with increasing the number of layers, the capture rate increased significantly. By optimizing the filter design, we succeeded in removing 100% of iron particles with a size of 48 microns in carbon black powder under low magnetic fields without clogging the filter. Consequently, it became clear that the newly developed filter is very effective in removing magnetic particles in the powder under dry condition.

刷辊式葡萄藤防寒土清土装置参数优化与试验研究

Aiming at the problems of low efficiency, and low degree of mechanization of artificial soil clearing and considering that grapevines are easy to be damaged in northern China, a brush roll grapevine cold-proof soil clearing device suitable for removing soil in northern grape planting areas is studied and designed. The machine is mainly composed of a suspension device, soil removing device, hydraulic control system, telescopic device, etc. In this paper, a brush roll grapevine cold-proof soil clearing device was fabricated to investigate critical parameters such as rotation rate of soil removing device, brush spacing, and brush wire length on the machine performance. The three-factor and three-level quadratic regression orthogonal tests were carried out with the rotation rate of soil removing device, brush spacing, and brush wire length were taken as experimental factors and the soil removal rate and soil clearing distance were used as the evaluation indexes of soil clearing effect. The results show that the influence order of three factors on the soil removal rate was: rotation rate of soil removing device > brush spacing > brush wire length. The order of influence on the soil clearing distance was: rotation rate of soil removing device > brush wire length > brush spacing. The results show that when the rotation rate of the soil removing device was 248.71 r/min, brush spacing was 18.84 mm and brush wire length was 329.3 mm, the soil removal rate was 91.62% and the soil clearing distance was 11.63 cm. The relative error between the experimental verification value and the theoretical optimization value is less than 4%. This study provides the theoretical basis for the development of other types of grapevine coldproof soil clearing devices.