Wire Resistance Research Articles

NAND Flash Based Novel Synaptic Architecture for Highly Robust and High-Density Quantized Neural Networks With Binary Neuron Activation of (1, 0)

We propose a novel synaptic architecture based on a NAND flash memory for highly robust and high-density quantized neural networks (QNN) with 4-bit weight and binary neuron activation, for the first time. The proposed synaptic architecture is fully compatible with the conventional NAND flash memory architecture by adopting a differential sensing scheme and a binary neuron activation of (1, 0). A binary neuron enables using a 1-bit sense amplifier, which significantly reduces the burden of peripheral circuits and power consumption and enables bitwise communication between the layers of neural networks. Operating NAND cells in the saturation region eliminates the effect of metal wire resistance and serial resistance of the NAND cells. With a read-verify-write (RVW) scheme, low-variance conductance distribution is demonstrated for 8 levels. Vector-matrix multiplication (VMM) of a 4-bit weight and binary activation can be accomplished by only one input pulse, eliminating the need of a multiplier and an additional logic operation. In addition, quantization training can minimize the degradation of the inference accuracy compared to post-training quantization. Finally, the low-variance conductance distribution of the NAND cells achieves a higher inference accuracy compared to that of resistive random access memory (RRAM) devices by 2~7 % and 0.04~0.23 % for CIFAR 10 and MNIST datasets, respectively.

Active Currents, Power Factor, and Apparent Power for Practical Power Delivery Systems

Concepts of apparent power and power factor as measures of a system's power delivery capability are over a century old but have not been defined in one general, rigorous and acceptable way. Instantaneous power is defined precisely, and average power measured over a selected period is widely accepted. The many ways of defining and measuring reactive and apparent power in single and three phase systems are based on different assumptions and give different results in real cases. Building on definitions in the IEEE Standard 1459-2010, this paper formulates in vector space linear algebra and the frequency domain, the active wire currents as those that cause the minimum losses in a network for the power delivered. Power factor measures the relative efficiency of power delivery as defined by the losses. Apparent power consistent with early terminology is the maximum power that can be sourced for the same original line losses and has the unit of power: Watt. It is identified without requiring the contentious concept of reactive and non-active power components. Measurements based on this approach are independent of assumptions about sinusoidal waveform, voltage and current balance, and frequency-dependent wire resistances, and apply to power delivery systems with any number of wires. The rigor of this novel general formulation is important for technical design of compensators and inverters; analyzing power system losses, delivery efficiency and voltage stability; and electricity cost allocation and pricing.

EMF Analysis for a 380kV Transmission OHL in the Vicinity of Buried Pipelines

The induction of Electromagnetic Fields that are generated through the interaction of highvoltage transmission lines with neighboring buried metallic pipelines produce uncontrolled hazardous potential voltages, which can infringe safety limits. The paper presents the findings of the electromagnetic interference effects on water buried pipelines constructed within the vicinity of an Extra High-Voltage 380 kV transmission overhead line (OHL) in Riyadh-Salboukh route within the Saudi national grid power network. The presented case study showed that some segments of the buried pipelines under this line have not experienced voltages that exceeded the standard limits for the steady-state condition. However, in the event of L-G fault currents (short circuits), the pipelines experienced a voltage level that is above the local electric utility safety limits. Therefore, the work produced implemented the mitigation method of gradient control wires to reduce the potential voltages experienced by the pipelines to enforce the safety limit. The variation of wire resistance has been proven to be a feasible solution to reduce the excessive induced voltages. The comparison has shown that a 0.1 Ω is sufficient to maintain the safe limit for at least this line. These findings may vary depending on the OHL design and site topology.

Miniature Biomass Conversion Unit for Learning the Fundamentals of Heterogeneous Reactions through Analysis of Heat Transfer and Thermochemical Conversion

HighlightsA miniaturized thermochemical conversion system has been designed, manufactured, and optimized.Five laboratories can be performed with the system, incorporating heat transfer and reaction engineering phenomena.Educational materials to deploy the system in the classroom, including worksheets and solutions, are provided.Pyrolysis, combustion, and gasification exercises are shown with reaction visualization and product validation.Abstract. We describe a simple new miniaturized thermochemical module (MTM). Special considerations are needed to make the MTM useful not only for studying biomass conversion but also for providing safe classroom learning opportunities for heat and mass transfer and heterogeneous reaction engineering students and for training new researchers. The MTM consists of a quartz reactor wrapped with a Kanthal resistance wire and a silvered concentric annular glass shield for retaining thermal energy, placed in a protective Plexiglas viewing case. Safety is considered for use by new research trainees and within the classroom. We demonstrate MTM usage through five laboratory exercises beginning with an experimental design to determine operating modes to establish thermochemical conversion temperatures. Heat transfer skills are developed with the aid of a first-order differential heat transfer model and fractional factorial design. Thermochemical conversion is demonstrated and products are validated for pyrolysis, gasification, and combustion. The combustion laboratory also offers significant insight into reaction versus mass transfer-controlled regimes and for modeling heat transfer. Discussion is provided on the utility of the system for demonstrating heat transfer, kinetic, and mass transfer concepts, with applications across the engineering curriculum. Keywords: Combustion, Education, Gasification, Heat transfer modeling, Miniature thermochemical module, Pyrolysis.

Improving the efficiency of oilfield electric power distribution

The issues of increasing the efficiency of electricity transmission to consumers with different nature of their load are considered. The dependence of the efficiency of the electric network of the oil field, consisting of a power line and a step-down transformer, on the total load power at various ratios between the active and reactive components of the power is analyzed, and the conditions under which the maximum transmission efficiency can be ensured are determined. It is shown by examples that the power transmission efficiency depends not only on the active load, but also largely on its reactive load. In the presence of a constant reactive load and an increase in active load, the total power increases and the power transmission efficiency decreases. In the low-load mode, the schedule for changing the power transmission efficiency approaches a parabolic form, since the influence of the active load on the amount of active power loss decreases, and their value will mainly depend on reactive load, which remains unchanged. The efficiency reaches its maximum value provided that the active and reactive components of the power are equal. In the case of a different ratio between them, the efficiency decreases. With a simultaneous increase in active and reactive loads and a constant value of the power factor, the power transmission efficiency is significantly reduced due to an increase in losses. With a constant active load and an increase in reactive load, efficiency of power transmission decreases, since with an increase in reactive load, losses of active power increase, while the active power remains unchanged. The second condition, under which the line efficiency will be maximum, is full compensation of reactive power. Therefore, in order to increase the efficiency of power transmission, it is necessary to compensate for the reactive load, which can reduce the loss of electricity and the cost of its payment and improve the quality of electricity. Other methods are also proposed to increase the efficiency of power transmission by regulating the voltage level in the power center, reducing the equivalent resistance of the line wires, optimizing the loading of the transformers of the step-down substations and ensuring the economic modes of their operation.

An experimental study for determination of convective heat transfer coefficients on cooling monofilament

In this study, the convective heat transfer coefficient around small diameter circular wires is determined in an effort to obtain main parameters affecting monofilament cooling process. The different diameter wires and air velocities were employed for detailed research in parallel and cross flow by using a wind tunnel. These correlations were based on conditions used in monofilament yarn production line. The wire diameters which were used in the experiments are vary from 0.2 mm to 1 mm while air velocities 0.5 m/s to 5 m/s as well. These wires were heated with power supply and cooled with specified air flow for the determination of convective heat transfer coefficient. A high precision multi-meter was used to measure the voltage and current values and then the wire surface temperatures have been determined by means of calculated wire resistance. The convective heat transfer coefficients were obtained by subtracting the radiation heat transfer from total heat transfer. The experiments were carried out with different Reynolds numbers. Finally, the resulting Nusselt correlations were compared with the correlations reported by Glicksman, Copley, Fand and Keswani, Churcill and Bernstein, Hilpert, Mc Adams, Dito, Brünig and, Kase and Matsuo. Results are in good agreement with literature for the same range of Reynolds numbers.

The Problem of Copper Softening During Cold Gas Dynamic Spraying

The effect of the gas-dynamic (cold) spraying of the Cu-Al2O3-Zn powder mixture on the microstructure and strength of the copper substrate is investigated. A copper cold drawn contact wire was used as a substrate. We propose using gas-dynamic cold spraying to restore the local wear of the contact wire. The study of the microstructure using the electron backscattered diffraction (EBSD) method showed the presence of grain orientation characteristics of the cold drawing of copper. Recrystallization of the surface layers of the contact wire during spraying does not occur. Using the microhardness measurement, the absence of softening of the layers of the contact wire with a depth of up to 2 mm is shown. The results of mechanical tests show that spraying does not lead to a decrease in the tensile strength of the contact wire. The results of creep tests show that spraying does not lead to a decrease in the heat resistance of the contact wire.

A Parasitic Resistance-Adapted Programming Scheme for Memristor Crossbar-Based Neuromorphic Computing Systems.

Memristor crossbar arrays without selector devices, such as complementary-metal oxide semiconductor (CMOS) devices, are a potential for realizing neuromorphic computing systems. However, wire resistance of metal wires is one of the factors that degrade the performance of memristor crossbar circuits. In this work, we propose a wire resistance modeling method and a parasitic resistance-adapted programming scheme to reduce the impact of wire resistance in a memristor crossbar-based neuromorphic computing system. The equivalent wire resistances for the cells are estimated by analyzing the crossbar circuit using the superposition theorem. For the conventional programming scheme, the connection matrix composed of the target memristance values is used for crossbar array programming. In the proposed parasitic resistance-adapted programming scheme, the connection matrix is updated before it is used for crossbar array programming to compensate the equivalent wire resistance. The updated connection matrix is obtained by subtracting the equivalent connection matrix from the original connection matrix. The circuit simulations are performed to test the proposed wire resistance modeling method and the parasitic resistance-adapted programming scheme. The simulation results showed that the discrepancy of the output voltages of the crossbar between the conventional wire resistance modeling method and the proposed wire resistance modeling method is as low as 2.9% when wire resistance varied from 0.5 to 3.0 Ω. The recognition rate of the memristor crossbar with the conventional programming scheme is 99%, 95%, 81%, and 65% when wire resistance is set to be 1.5, 2.0, 2.5, and 3.0 Ω, respectively. By contrast, the memristor crossbar with the proposed parasitic resistance-adapted programming scheme can maintain the recognition as high as 100% when wire resistance is as high as 3.0 Ω.

Corrosion Resistance of Nitinol Wires After Deformation

The corrosion resistance of thin NiTi wires in unstrained state and at 6% of pseudoelastic strain was determined by cyclic potentiodynamic polarization, considering a surface area of 2.3 cm2, equivalent to that of an actual minimally invasive implant. Surface finishing was carried out by mechanical polishing, electropolishing, and subsequent heat treatment in a salt bath furnace. Topography, microstructure, and composition of the respective surfaces were characterized in detail using light and electron microscopy, as well as glow discharge optical emission spectroscopy. Whereas breakdown below 1000 mV was observed for wires in mechanically polished condition in unstrained and strained state, wires in electropolished and electropolished + heat-treated condition exhibit no breakdown up to 1000 mV. Multiple testing reproduced uniform potentiodynamic polarization curves in unstrained and strained state. Accordingly, the observed formation of cracks in the surface oxide layer of wires in electropolished + heat-treated condition is concluded to be negligible in unstrained and strained state. Cause for the observed high performance of both the electropolished and the electropolished + heat-treated wires is apparently the smoothing of the initial surface that results in a homogeneous oxide layer even after heat treatment.

Excalibur: An Accurate, Scalable, and Low-Cost Calibration Tool for Sensing Devices

Calibration of an analog-to-digital converter is an essential step to compensate for static errors and ensure accurate digital output. In addition, ad-hoc deployments and operations require fault-tolerant IoT devices capable of adapting to unpredictable environments. In this paper, we present the design and implementation of Excalibur – a low-cost, accurate, and scalable calibration tool. Excalibur is a programmable platform, which provides linear current output and rational function voltage output with a dynamic range. The basic idea is to use a set of digital switches to connect with a parallel resistor network and program the digital switches to change the total resistance of the circuit. The total resistance and output frequency of Excalibur is controlled by a program communicating through the GPIO and I2C interfaces. The software provides two salient features to improve accuracy and reliability: time synchronization and self-calibration. Furthermore, Excalibur is equipped with a temperature sensor to measure the temperature before calibration, and a current sensor which enables current calibration without using a digital multimeter. We present the mathematical model and a solution to compensate for thermal and wire resistance effects and validate scalability by incorporating the concept of the Fibonacci sequence. Our extensive experimental studies show that Excalibur can significantly improve measurement accuracy. For example, for ATMega2560, the ADC error reduces from 0.2% to 0.01%, for ADS8353, the error reduces from 0.17% to 0.0014%, for INA219, the error reduces from 0.42% to 0.02%, and for MCP3208, the error reduces from 5.29% to 0.01%.

An artificial muscle driven by decomposition of gas solution

This note develops an artificial muscle driven by the decomposition of gas solution. It mainly consists of a silicone tube, a resistive wire, a braided mesh shell, and an amount of gas solution which can be decomposed reversibly by temperature variation. It can be operated directly by supplying the resistive wire with controllable electrical power, which is different from traditional fluidic artificial muscles requiring external pressure generating devices. To verify the effectiveness of the artificial muscle, prototypes are fabricated and the process is presented in detail. Ammonia solution is employed in the prototypes due to its high solubility and low decomposition temperature. Experiments under both isometric and isotonic contractions are implemented and the results show that the prototypes can achieve good mechanical performance.

Research on the Effect of Imprecise Size Foam Samples on Acoustic Measurements in Impedance Tube

Polymer foam materials are very commonly used acoustic materials for absorbing sound energy in noise control engineering, because of their higher porosity and light in weight. The acoustic characterization of these materials namely; absorption coefficient and transmission loss are measured using impedance tube, reverberation room method and intensity methods. Among these three impedance tube is the most popular method in laboratory condition. Here the sample size plays a main role in the accurate characterization acoustic materials by using the impedance tube. The present paper discusses effect of variation in the sample size on their acoustic measurements. The foam sample are prepared using Resistance wire foam cutter(RWFC). Their absorption coefficient and transmission loss for large and small samples with variations in sample dimensions are measured and compare with ideal dimension results. A detailed measured data and analysis are done to understand the effect of undersized and oversized foam samples on absorption coefficient and transmission loss results as a function of frequency. The results show that the variations in sample size has immense effect of measured results. The results presented in this study becomes a guideline for characterizing acoustic materials using impedance tube.

From Bore\u2013Soliton\u2013Splash to a New Wave-to-Wire Wave-Energy Model

We explore extreme nonlinear water-wave amplification in a contraction or, analogously, wave amplification in crossing seas. The latter case can lead to extreme or rogue-wave formation at sea. First, amplification of a solitary-water-wave compound running into a contraction is disseminated experimentally in a wave tank. Maximum amplification in our bore–soliton–splash observed is circa tenfold. Subsequently, we summarise some nonlinear and numerical modelling approaches, validated for amplifying, contracting waves. These amplification phenomena observed have led us to develop a novel wave-energy device with wave amplification in a contraction used to enhance wave-activated buoy motion and magnetically induced energy generation. An experimental proof-of-principle shows that our wave-energy device works. Most importantly, we develop a novel wave-to-wire mathematical model of the combined wave hydrodynamics, wave-activated buoy motion and electric power generation by magnetic induction, from first principles, satisfying one grand variational principle in its conservative limit. Wave and buoy dynamics are coupled via a Lagrange multiplier, which boundary value at the waterline is in a subtle way solved explicitly by imposing incompressibility in a weak sense. Dissipative features, such as electrical wire resistance and nonlinear LED loads, are added a posteriori. New is also the intricate and compatible finite-element space–time discretisation of the linearised dynamics, guaranteeing numerical stability and the correct energy transfer between the three subsystems. Preliminary simulations of our simplified and linearised wave-energy model are encouraging and involve a first study of the resonant behaviour and parameter dependence of the device.

Influence of shield wires on geomagnetically induced currents in power systems

There is increasing interest in assessing the GIC risk to power systems with GIC disturbing events to power systems observed in many parts of the world. An essential step in GIC risk assessment is modeling of GIC. Many factors have been considered in the GIC network model, but the effect of shield wires is still not clear. In this paper, we investigate multiple ways in which shield wires can influence the GIC in the transmission lines, including: mutual inductance between the shield wire and the transmission line, voltage change in substation grounding resistance due to GIC flowing to/from the shield wire, the geoelectric field distortion due to GIC flowing to/from the shield wire through tower footings and the influence of shield wires on the effective substation grounding resistance. Typical values for each effect are calculated to determine the significance of the shield wire effect on GIC. For the situations considered, the effect of shield wires on the effective substation grounding resistance is the only one that significantly affects GIC in transformers. To include this effect in GIC modeling a simple formula is given for the resistance of a shield wire and tower network.

Hot-wire thermal stress cleaving process of glass with micro crack-free edges

ABSTRACTMicro cracks can form on the edges of ultra-thin glass sheets during the cutting processes that use a laser beam or a diamond scriber. These micro cracks can extend to the surface, and thus, it is difficult to prevent ultra-thin glass sheets cut using these existing processes from fracturing under either external stress or acceleration. A thermal stress cleaving process that uses a heated electric resistance wire to avoid micro cracks during the cutting process was proposed. The glass sheets are cleaved following a defined profile because of the thermal stress. In this study, a hot-wire thermal stress cleaving model was investigated based on the principle of thermal stress fracture. The thermal stress in the material was calculated. Experimental studies are performed to investigate the processing parameters, and glass sheet with thickness of 300 µm was cut, resulting in micro crack-free edges with a surface roughness of 0.5 nm. The proposed process was also applied to cut X-ray telescope lenses substrates with no micro cracks. Compared with diamond scribing and laser cutting, the proposed method is lower capital costs and yields a nondestructive cut surface for glass. The technique can be applied in manufacturing glass products (i.e. lenses, solar cells, glass screen).

Novel Method for State Space Modeling of Full Bridge Converter

The requirement of converters is increasing with the increase in demand for the power conversion devices. For efficient power conversion, stability and time response of the system must be improved. For improving characteristics a mathematical model of the system must be determined. In this paper, an improvised state space model of full bridge converter is presented which can be used in converter design. This state-space model incorporates the non-idealities of the transformers like discharge time of primary inductance and secondary inductance as well as the wire resistance. The interdependency of the parameters affects the state space model of the converter compared to the ideal modeling. This variation in state space model of the converter has an impact on design of compensator which improves the system efficiency of the converter.

Enhanced Interfacing o f Single Element Resistive Sensor w ith Microcontroller

Resistive sensors can be used in a single element, differential and bridge forms. Resistive sensors have wide applications in industries. When the resistive sensor is directly connected with the microcontroller large amount of error arises due to lead wire resistance and microcontroller port pin resistances. Here, an enhanced interfacing of single element resistive sensor with a microcontroller scheme is proposed to compensate the error due to lead wires and port pin resistances. This scheme follows three discharge cycles for the measurement of resistances of the resistive sensor. The time taken for each discharge cycle is noted. From the time taken for the three discharge cycles, the resistance of the resistive sensor is directly calculated. Since the resistances due to lead wires and internal port pin resistances are corrected, the unknown temperature measurement is done accurately.

Compensating Circuit to Reduce the Impact of Wire Resistance in a Memristor Crossbar-Based Perceptron Neural Network.

Wire resistance in metal wire is one of the factors that degrade the performance of memristor crossbar circuits. In this paper, an analysis of the impact of wire resistance in a memristor crossbar is performed and a compensating circuit is proposed to reduce the impact of wire resistance in a memristor crossbar-based perceptron neural network. The goal of the analysis is to figure out how wire resistance influences the output voltage of a memristor crossbar. It emerges that the wire resistance on horizontal lines causes the neuron’s output voltage to vary more than the wire resistance on vertical lines. More interesting, the voltage variation caused by wire resistance on horizontal lines increases proportionally to the length of metal wire. The first column has small voltage variation whereas the last column has large voltage variation. In addition, two adjacent columns have almost the same amount of voltage variation. Under these observations, a memristor crossbar-based perceptron neural network with compensating circuit is proposed. The neuron’s outputs of two columns are put into a subtractor circuit to eliminate the voltage variation caused by the wire resistance. The proposed memristor crossbar-based perceptron neural network is trained to recognize the 26 characters. The proposed memristor crossbar shows better recognition rate compared to the previous work when wire resistance is taken into account. The proposed memristor crossbar circuit can maintain the recognition rate as high as 100% when wire resistance is as high as 2.5 Ω. By contrast, the recognition rate of the memristor crossbar without the compensating circuit decreases by 1%, 5%, and 19% when wire resistance is set to be 1.5, 2.0, and 2.5 Ω, respectively.

The application of manganin wire pressure gauges in a large volume press under high-temperature conditions

ABSTRACTThe in-situ observation of pressure inside a sample chamber was made by exploiting the piezoelectric effect in manganin wire. This was done by considering temperatures of room temperature (±1°C), 600°C (±3°C), and 900°C (±3°C), pressure range of 0–2.4 GPa (±0.1 GPa), and the inferring a relationship between the relative resistance of manganin wire and the pressure inside the sample chamber for the different temperatures, allowing the pressure to be found.

Design of 100A High Stability Sampling Resistance

In this paper, multiple manganese-copper resistance wires are connected in parallel as the basic structure of the sampling resistor. The stability of the resistance wire is analysed when the conductor is connected in parallel and twisted, and the resistance wire of the sampling resistor is determined to be connected in a twisted manner to reduce the influence of interference on the measurement. Sampling resistance is annealed in a thermostat to release the internal stress of the stranded wire. Experiments show that the resistance has a stability of 7 ppm for 8 hours. The resistance is connected to a high stability constant current source for testing. The short-term stability of the constant current source is better than 10 ppm, which meets the design requirements.