Parametric dependence of lightning impulse behavior of grounding electrodes buried in a dispersive and ionized lossy soil under first- and subsequent-stroke currents

2020 ◽  
Vol 39 (4) ◽  
pp. 757-773 ◽  
Author(s):  
Seyed Sajad Sajadi ◽  
Saeed Reza Ostadzadeh ◽  
Seyed Hossein Hesamedin Sadeghi
Keyword(s):  
Computational Efficiency ◽  
Design Methodology ◽  
Soil Surface ◽  
Effective Length ◽  
Sensitivity Analyses ◽  
Induced Voltage ◽  
Content Type ◽  
Parametric Dependence ◽  
Lightning Impulse ◽  
Simulation Results

Purpose The purpose of this paper is to investigate the simultaneous effects of ionization and dispersion of soil on the impulse behavior of grounding electrodes under first and subsequent stroke currents. Design/methodology/approach A recently introduced technique called improved multi-conductor transmission line (MTL) is simplified for grounding electrodes buried in both-affected soils. Findings The simulation results show that including the two effects simultaneously in highly resistive soils under high-valued subsequent stroke current is recommended. Otherwise, simultaneous effects can be disregard. Originality/value To the best of the authors’ knowledge, there is no research on sensitivity analyses for the simultaneous inclusion of the two effects on the effective length and the induced voltage on the soil surface. To this end, the simplified MTL is applied to the grounding electrodes. The simulation results show that the computational efficiency in comparison with previous methods is, first, considerably increased. Second, the simultaneous effects result in decreasing the soil surface voltage with respect to situations where either ionization or dispersion is taken into account (single-affected soils). In other words, the performance of grounding systems is improved. Third, the effective length in both-affected soil is has a middle value with respect to the single-affected soil. Such findings practically and financially are of importance.

Predicting formulae for effective length of counterpoise wires buried in ionized, dispersive and inhomogeneous soils

2020 ◽  
Vol 39 (6) ◽  
pp. 1375-1391
Author(s):  
Seyyed Sajjad Sajjadi ◽  
Saeed Reza Ostadzadeh
Keyword(s):  
Sensitivity Analysis ◽  
Transmission Line ◽  
Design Methodology ◽  
Effective Length ◽  
Transmission Line Model ◽  
Line Model ◽  
Content Type ◽  
Dispersion Effects ◽  
Simulation Results

Purpose The purpose of this paper is to investigate the ionization and dispersion effects in combination with the inhomogeneity of soil simultaneously on the effective lengths of counterpoise wires. Design/methodology/approach Improved multi-conductor transmission line model is used for computing effective length of counterpoise wires considering all aspects of soils. Findings The simulation results show that the ionization and dispersion effects simultaneously results in placing the effective length between situations where only one effect is considered. Also, predicting formulae for effective length of counterpoise wires considering all effects are proposed. Originality/value A sensitivity analysis on the effective lengths of counterpoise wires considering all aspects of soils is carried out.

Design and optimization of heating, cooling and lightening systems for a residential villa at Saman city, Iran

2019 ◽  
Vol 17 (1) ◽  
pp. 41-52 ◽  
Author(s):  
Javad Riahi Zaniani ◽  
Shahab Taghipour Ghahfarokhi ◽  
Mehdi Jahangiri ◽  
Akbar Alidadi Shamsabadi
Keyword(s):  
Energy Consumption ◽  
Light Intensity ◽  
Design Methodology ◽  
Climatic Conditions ◽  
Content Type ◽  
Design And Optimization ◽  
Simulation Results ◽  
Annual Reduction ◽  
Reduction Of Energy Consumption ◽  
Heating Loads

Purpose This paper, using energy softwares, designed of Iran and optimized a residential villa in Saman city located in Chaharmahal and Bakhtiari Province. Design/methodology/approach Having used the ideas of Climate Consultant software, the basic designing was conducted by Design Builder Software, and the cooling and heating loads and lighting tools and equipment were calculated. Then, the amount of consuming of heating, cooling and lighting load of the building was optimized through insulation of walls and ceiling, using green roof, double glazing UPVC windows, light intensity sensor and variable refrigerant flow (VRF) system. Findings Simulation results for the stated scenarios showed an annual reduction in energy consumption of 21.1, 7.9, 26.41, 27.3 and 72.3 per cent, respectively. Also, by combining all the five scenarios, an optimal state was achieved which, from the results, brought about an annual reduction of 86.9 per cent in the energy consumption. Originality/value The authors hope that the results of the current paper could be helpful for designers and engineers in reduction of energy consumption for designing a building in similar climatic conditions.

Design and vibration analysis of a self-adaptive piston in a novel nanoimprint system

2017 ◽  
Vol 69 (4) ◽  
pp. 591-597
Author(s):  
Chaoran Liu ◽  
Yufeng Su ◽  
Jinzhao Yue ◽  
Junjie Wang ◽  
Weiwei Xia ◽  
...  
Keyword(s):  
Nanoimprint Lithography ◽  
Vibration Analysis ◽  
Design Methodology ◽  
The Self ◽  
Ball Screw ◽  
Piston Rings ◽  
Content Type ◽  
Simulation Results ◽  
The One ◽  
Self Adaptive

Purpose A self-adaptive piston is designed for the compressional gas cushion press nanoimprint lithography system. It avoids the lube pollution and high wear of traditional piston. Design/methodology/approach The self-adaptive piston device consists of symmetrical piston bodies, piston rings and other parts. The two piston bodies are linked by a ball-screw. The locking nut adjusts the distance between two piston bodies to avoid the piston rings from being stuck. The piston rings are placed between two piston bodies. Findings The simulation results based on COMSOL indicate that cylinder vibration caused by self-adaptive piston is 15.9 times smaller than the one caused by a traditional piston. Originality/value The self-adaptive piston is superior to the traditional piston in decreasing cylinder vibration.

An improved circuit for modulator based on nanostructured memristor

Circuit World ◽  
2016 ◽  
Vol 42 (4) ◽  
pp. 178-182 ◽  
Author(s):  
Shao-Fu Wang ◽  
D.Z. Xu
Keyword(s):  
Amplitude Modulation ◽  
Design Methodology ◽  
Content Type ◽  
Amplitude Modulator ◽  
Simulation Results

Purpose This paper aims to propose the modeling of nanostructured memristor, and the circuit of amplitude modulator was designed and analyzed with memristor. The simulation results show that the nanostructured memristor can be utilized to implement the desired amplitude modulated signal. Design/methodology/approach The modeling of nanostructured memristor is proposed in this paper, and the circuit of amplitude modulator was designed and analyzed with memristor, amplifiers and BPF device. For measuring the modulated signal, the emulator circuit of memristor is designed. The simulation results show that the nanostructured memristor can be utilized to implement the desired amplitude modulated signal. Findings The innovations of this work are as follows: the AM modulator circuit using memristor has been proposed, analyzed and simulated. The emulator of memristor is given. Originality/value The innovations of this work are as follows: the AM modulator circuit using memristor has been proposed, analyzed and simulated. The emulator of memristor is given, and the results of this work demonstrate that the nonlinearity of the memristor can be used to generate the desired amplitude modulation free of harmonic sidebands, because of distortion of the modulating signal.

Induction motors broken rotor bars detection using RPVM and neural network

2019 ◽  
Vol 38 (2) ◽  
pp. 596-615 ◽  
Author(s):  
Saddam Bensaoucha ◽  
Sid Ahmed Bessedik ◽  
Aissa Ameur ◽  
Ali Teta
Keyword(s):  
Design Methodology ◽  
Induction Motors ◽  
Content Type ◽  
Broken Rotor Bars ◽  
Squirrel Cage ◽  
Detection And Identification ◽  
Squirrel Cage Induction Motor ◽  
Simulation Results ◽  
Cage Induction Motor ◽  
Diagnosis Technique

Purpose The purpose of this study aims to focus on the detection and identification of the broken rotor bars (BRBs) of a squirrel cage induction motor (SCIM). The presented diagnosis technique is based on artificial neural networks (NNs) that use as inputs the results of the spectral analysis using the fast Fourier transform (FFT) of the reduced Park’s vector modulus (RPVM), along with the load values in which the motor operates. Design/methodology/approach First, this paper presents a comparative study between FFT applied on Hilbert modulus, Park’s vector modulus and RPVM to extract feature frequencies of BRB faults. Moreover, the extracted features of FFT applied to RPVM and the load values were selected as NNs’ inputs for the detection of the number of BRBs. Findings The obtained simulation results using MATLAB (Matrix Laboratory) environment show the effectiveness and accuracy of the proposed NNs based approach. Originality/value The current paper presents a novel diagnostic method for BRBs’ fault detection in SCIM, based on the combination between the signal processing analysis (FFT of RPVM) and artificial intelligence (NNs).

Temperature distribution simulations during electron beam freeform fabrication process based on the fully threaded tree

2019 ◽  
Vol 25 (6) ◽  
pp. 989-997
Author(s):  
Yajun Yin ◽  
Wei Duan ◽  
Kai Wu ◽  
Yangdong Li ◽  
Jianxin Zhou ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Temperature Field ◽  
Electron Beam ◽  
Additive Manufacturing ◽  
Temperature Distribution ◽  
Design Methodology ◽  
Content Type ◽  
Freeform Fabrication ◽  
Simulation Based ◽  
Simulation Results

Purpose The purpose of this study is to simulate the temperature distribution during an electron beam freeform fabrication (EBF3) process based on a fully threaded tree (FTT) technique in various scales and to analyze the temperature variation with time in different regions of the part. Design/methodology/approach This study presented a revised model for the temperature simulation in the EBF3 process. The FTT technique was then adopted as an adaptive grid strategy in the simulation. Based on the simulation results, an analysis regarding the temperature distribution of a circular deposit and substrate was performed. Findings The FTT technique was successfully adopted in the simulation of the temperature field during the EBF3 process. The temperature bands and oscillating temperature curves appeared in the deposit and substrate. Originality/value The FTT technique was introduced into the numerical simulation of an additive manufacturing process. The efficiency of the process was improved, and the FTT technique was convenient for the 3D simulations and multi-pass deposits.

scholarly journals On-demand food delivery: investigating the economic performances

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Arianna Seghezzi ◽  
Riccardo Mangiaracina
Keyword(s):  
Purchase Intention ◽  
Design Methodology ◽  
Food Delivery ◽  
Sensitivity Analyses ◽  
Base Case ◽  
Content Type ◽  
On Demand ◽  
Last Mile ◽  
Potential Impact ◽  
Positive Results

PurposeThis paper focusses on on-demand food delivery (ODFD), i.e. the delivery of freshly prepared meals to customers' homes, enabled by the use of online platforms. In ODFD, a key process is represented by last-mile deliveries (LMDs): they directly affect customers (the delivery price influences their purchase intention), riders (the compensation drives their willingness to perform deliveries) and platforms (deliveries are very expensive). In this context, this work aims to investigate the economic performances of ODFD LMDs.Design/methodology/approachThis study adopts a multi-method threefold process. First, it develops a model that – after the generation of customers' demand and the assignment of deliveries to available riders – identifies incomes and costs faced by an ODFD operator. Second, the model is applied to a base case in Milan (Italy). Third, sensitivity analyses are performed (on daily demand and riders' salary).FindingsThe analyses allow – besides the identification of significant values associated to ODFD profitability – to draw general insights about delivery price (e.g. free delivery is not economically sustainable), daily demand (e.g. greater demand values do not only improve positive results but also worsen negative ones) and fixed/variable wage mix (e.g. increasing the variable wage enhances the profitability for platforms).Originality/valueOn the academic side, this word enhances extant literature about ODFD, proposing a model – with multidisciplinary implications – to strategically investigate profitability conditions of LMDs. On the managerial side, it provides support for (logistics/marketing) ODFD practitioners since it allows to evaluate the potential impact of significant decisions on profitability.

Performance analysis of PCM curtain for thermal comfort

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shubham Srivastava ◽  
Abhishek Srivastava ◽  
Sanya Jain ◽  
Nandan Kumar ◽  
Chandra Shekhar Malvi
Keyword(s):  
Thermal Comfort ◽  
Design Methodology ◽  
Phase Change Materials ◽  
Heat Exposure ◽  
Mean Square ◽  
Constant Heat ◽  
Content Type ◽  
One Dimensional ◽  
Simulation Results ◽  
Modelling Assumptions

Purpose This study aims to analyse the variations of thermal comfort inside a building space by using different curtains. Design/methodology/approach Phase change materials (PCMs) such as wax, sand and mixture of sand and wax were used with cotton curtain to compare the results of PCM curtains with the performance of normal cotton curtain against constant heat exposure. Heat exposure was provided with halogen to simulate the solar radiation. Further simulation was performed on ANSYS and experimental results were compared with the simulation results. In addition to this, the results were analysed for optimized performance by calculation root mean square error. Findings It was found that PCM used curtains that have better performance than normal curtain. Furthermore, sand curtain was proved as the best curtain and mixture of sand and wax curtain could replace the sand curtain where there is limitation of weight; also, there was less error between experimental and simulation was reported for sand curtain as compare to other curtains. Research limitations/implications Layers of different PCMs were used before cotton curtain and in modelling assumptions such as one-dimensional heat transfer, uniform thermal conductivity. Originality/value To the best of the authors’ knowledge, there is no such study that was performed earlier.

Pantograph-catenary contact reliability analysis under crosswind

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yong-Hua Li ◽  
Yang Cao ◽  
Yong-Xin Wu ◽  
Xiao-Ning Bai ◽  
Jia-Wei Mao
Keyword(s):  
Relative Motion ◽  
Design Methodology ◽  
Effective Length ◽  
Design Parameters ◽  
Lateral Deviation ◽  
Vector Method ◽  
Content Type ◽  
Bird Swarm Algorithm ◽  
The Relationship

PurposeThis paper aims to establish the relationship between crosswind speed and pantograph-catenary lateral deviation, as well as quantify the influence of crosswind speed and rod size uncertainty on pantograph-catenary contact reliability.Design/methodology/approachThe closed vector method is used to establish the pantograph-catenary kinematics formula. A new prediction model is proposed by using the bird swarm algorithm to optimize the grey model. The lateral deviation of the pantograph and catenary is predicted via the new model. Then the relationship between the effective length of the rod and operating mileage is inferred by combining the effective length theory with the Gamma process, as well as the pantograph-catenary contact reliability model is established according to reliability theory.FindingsThe results obtained show the impacts of uncertainty design parameters of pantograph rods on pantograph-catenary contact reliability index, and the results at crosswind speed of 0 ms−1 and 5 ms−1 are 5.0630 and 4.1442, respectively. The reliability decreases with the increasing crosswind speed, and can be greater than the reliability calculated for rod size degradation due to long-term use.Originality/valueMost preceding works on pantograph-catenary contact reliability were based on principles of dynamics, without considering the pantograph-catenary relative motion. This research reveals the law of pantograph-catenary relative motion for uncertainty design parameters and crosswind, and quantifies the reliability from the angle of kinematics.

The gyrator for transforming nano memristor into meminductor

Circuit World ◽  
2016 ◽  
Vol 42 (4) ◽  
pp. 197-200 ◽  
Author(s):  
Shao-Fu Wang
Keyword(s):  
Circuit Design ◽  
Constitutive Relation ◽  
Integrated Circuit ◽  
Design Methodology ◽  
Synthesis Method ◽  
Integrated Circuit Design ◽  
Content Type ◽  
Simulation Results

Purpose To solve the problem of meminductor in circuit design, this paper aims to describe a synthesis method and the mechanism in terms of constitutive relation of the gyrator for transforming nano memristor into meminductor. Design/methodology/approach The gyrator was designed to achieve memristor-meminductor transformation by using amplifiers and memristor. Findings The simulation results verify the flexibility of its operation. Originality/value This gyrator can be used in integrated circuit design such as filter, diplexer, and it has a simple and economical implementation.

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