International Journal of Engineering
Volume:35 Issue: 11, Nov 2022

Face recognition (FR) is a challenging computer vision task due to various adverse conditions. Local features play an important role in increasing the recognition rate of an FR method. In this direction, the covariance descriptors of Gabor wavelet features have been one of the most prominent methods for accurate FR. Most existing methods rely on covariance descriptors of Gabor magnitude features extracted from single-scale face images. This study proposes a new method named multiscale Gabor covariance-based ensemble Log-euclidean SVM (MGcov-ELSVM) for FR that uses the covariance descriptors of Gabor magnitude and phase features derived from multiscale face representations. MGcov-ELSVM begins by producing multiscale face representations. Gabor magnitude and phase features are derived from the multiscale face images in the second stage. After that, the Gabor magnitude and phase features are used to generate covariance descriptors. Finally, Covariance descriptors are classified via a log-Euclidean SVM classifier, and a majority voting technique determines the final recognition results. The experimental results from two face databases, ORL and Yale, indicate that the MGcov-ELSVM outperforms some recent FR methods.

When elastic waves act on rocks, the structure of the void space changes. The nucleation and formation of new cracks is possible. Wave action technologies are divided into two groups: with a frequency of less than 100 Hz and a frequency of more than 1 kHz. In the intermediate zone, no completed works and studies of wave action were found. The paper studies the results of the impact of elastic waves with different frequencies and amplitudes on oil production. With low-frequency exposure, an increase in permeability values is noted to a greater extent due to the appearance of new and an increase in the size of existing cracks. With high-frequency exposure, the viscosity of reservoir oil is greatly reduced. The greater the value of the initial viscosity, the more intense it decreases when exposed to high-frequency waves. For the Perm Territory, a comparison was made of the results of wave processing of production wells depending on the frequency of exposure. As the impact frequency increases, the average oil recovery after wave treatment decreases. With an increase in the frequency of exposure, the duration of operation of a well with increased oil production after wave treatment decreases. Models have been obtained to predict the time of operation of wells with additional oil production, additional oil production and an increase in oil production rate of wells after wave action. As a result, it can be noted that the most effective technologies are those with a lower frequency, but a large amplitude of exposure.

Reviewing the efficiency of Research and Development (R&D) by giving an equal amount of importance to different R&D actions can make the measuring process too simple, which may cause an inaccurate interpretation of the R&D function and lead to an imprecise interpretation of R&D models. R&D comprises the creative work undertaken on a systematic basis to increase the stock of knowledge, including knowledge of man, culture, and society, and the use of this stock of knowledge to devise new applications. This research provides a two-phase approach to designing an R&D model in the auto battery manufacturing industry based on customer satisfaction. Due to the important role of R&D in customer satisfaction, no study has been conducted in this field and industry. In the first phase, the effective models for R&D management and the indices influencing customer satisfaction in R&D models are identified. In the second phase, the significance coefficients related to the customer satisfaction indices are obtained by using the fuzzy SWARA (Stepwise Weight Assessment Ratio Analysis) as a multi-criteria decision-making method. Furthermore, each model’s importance and final priority are calculated by the fuzzy COPRAS (Complex Proportional Assessment) method. Finally, to apply the proposed framework in the battery manufacturing industry, a bi-objective R&D model is presented. The coefficients obtained by the fuzzy COPRAS method are utilized as the input for the proposed model. Therefore, policy-makers and managers can perform their activities based on this method. The obtained results showed that the proposed framework is effective in the case under study.

This study presents an analytical solution for free vibration analysis of two-dimensional functionally graded (2D-FG) porous sandwich beams. The equations of motion for the beam were derived using Hamilton's principle, and then the Galerkin method was employed to solve the equations. The material properties of the sandwich beams vary with the thickness and length of each layer according to the power-law function. The mechanical properties gradually changed from aluminum to alumina as the metal and ceramic, respectively. The vibration analysis was investigated based on two new higher-order shear deformation beam theories (NHSDBTs). These two new theories do not need any shear correction factor and have fewer unknown variables than other higher order shear beam theories.  The obtained natural frequencies for the three types of beams were compared with the results of the Timoshenko, first-order , and parabolic shear deformation beam theories. In addition, the effects of porosity, L/h, and FG power indexes along the thickness and length on the non-dimensional frequency of three special types of beams are presented and discussed. Furthermore, the mode shapes of the beam are depicted for various FG power indexes based on these new theories. By comparing the results of the two proposed theories with those of existing studies, the accuracy of the proposed theories was validated. Power-law indexes shifted the node point to the left and resonance will be accrued sooner than the non-FGM beam.

There is a growing demand of suitable substitute materials of concrete ingredients especially fine and coarse aggregates in order to achieve sustainable development in the era of rapid urbanisation. Therefore, the concrete making process by utilisation of aggregates that recycled from construction and demolition (C&D) debris has emerged as a primary objective for many government agencies. Consequently, the utilisation of recycled aggregate concrete (RAC) in structural applications become essential aspect. However, RAC can be employed in structural applications only if effective stress-strain relationship is available. The stress-strain models developed for natural aggregate concrete (NAC) are not fully suitable for RAC. Hence, the selection of good model which has precise prediction capacity plays a crucial role. Moreover, the stress-strain models provide the basis for the analysis and modern design procedures especially in FEA packages. In the present study, the stress-strain models for RAC have been selected from the literature and critically reviewed in order to evaluate their predictive efficacy. The test samples in the form of measured stress-strain relations–hips derived from literature have been compared with the predictions of each selected model. Besides the comparison of measured and predicted stress-strain profiles, the output of selected models in terms of normalized toughness and ductility index was assessed. The consistency of output of models are further evaluated by employing statistical tools such as coefficient of variance and root mean square error. The outcomes of the model in the form of polynomial expression was relatively more accurate to that of other counterparts.

Cement Fly ash and Gravel Piles are modern soil improvement techniques widely used in China for infrastructure development. It significantly impacts the fundamental characteristics of load-carrying capacities and deformation. The cement fly ash and gravel (CFG) piles are located on highways, railway embankments, essential projects, and problematic soil. These are often subjected to high risk of external load like flooding, seismic, etc. In such a case, foundation design can be governed by a required lateral resistance. The present study is based on the deformation behaviour of a CFG pile subjected to axial, lateral, and combined loading in soft clay. Numerical analysis using Plaxis 3D on a CFG pile with various influencing parameters soil condition, diameters, length, length to diameter ratio, and pile head loading condition to observe its effect. Overall, the pile study found variations in initial stress level, pile type, and pile head constraint. Still, these were minor compared to the impact of soil behaviour and mobility. The soil models varied stiffness and strength properties. The effects originating from the boundary conditions used were responsible for significantly decreasing lateral resistance for inner CFG piles under the active and passive loading.

Bending strength, was assessed in glued laminated beams made from local wood species bonded with phenol resorcinol formaldehyde, polyurethane and urea-formaldehyde adhesives. The 3- point loading was used as the basis of bending strength assessment along the directions parallel and perpendicular to the glue line. The load orientation parallel to the glue line offered higher bending strength. Furthermore, the characteristic values of bending strength obtained were 35.16 N/mm2, 40.79 N/mm2, 47.34 N/mm2, 60 N/mm2, and 67 N/mm2 for Afara, Akomu, Gmelina, Iroko, and Omocedar wood species. These values are similar to strength values given in EN 1194-1999 for glulam beams. Consequently, the findings of the study are beneficial to architects and structural engineers in exploring the dimensional, strength, and architectural flexibility  glulam affords for both beam and column design and holds the potential for creating an industrial hub for enhancing the value chain around engineered wood and allied industries.

In developing countries like India, Multilane high-speed National Highways (NHs) are victims of high accident rates.  The Indian National Highway network comprises only 2% of the Indian road network, but transports 40% of traffic, resulting in traffic accidents on National Highways.  As observed from past studies, drivers are the main responsible factors for accident causation due to their risky behavior.  Hence, to determine significant factors causing the risky behavior of drivers on multi-lane high-speed highways, the personal interview survey through questionnaire was conducted for the road users of NH-47 comprising of the responses to the drivers' demographics, attitude towards vehicle condition and maintenance, traffic regulations/ enforcement following attitude characteristics, and roadway environment characteristics.  Principal component analysis (PCA) was applied to the questionnaire variables, and significant category-wise variables for risky driving were identified.  Fifteen important variables contributed to risky driving behavior from the questionnaire database by PCA.  They are Roadway environment characteristics like improper signals, roadside accident prevention infrastructure, improper pavement, and no safe crossing points; Driver's age and experience; Using mirrors while overtaking, using lights and dipper during night-time, and using hand signals during daytime; Using helmets and seatbelts while driving and having a valid vehicle insurance policy; age of the vehicles, vehicle service frequency, and lane preference in their decreasing significance based on the questionnaire database.  The authorities can take suitable measures to control the significant variables causing risky driving behavior on high speed multi-lane highways and reduce the accidents scenarios on the multilane highways.

Combining soil with some adsorbents improves soil structure and shear strength. Thus, an optimal ratio of some adsorbents in the soil composition enhances soil adsorption capacity, reduces the possibility of groundwater contamination with these hazardous compounds, and leads to increase soil resistance parameters. This paper investigates the effect of heavy metals and adsorbents on the geotechnical behavior of clayey sand soils contaminated with lead and zinc as heavy metals as well as zeolite and rice husk ash as adsorbents. Clayey sand (mixture of sand with 20% kaolinite or bentonite) was considered as a base composition and the behavior of it was studied in both contaminated and uncontaminated states. Then, for increasing the heavy metal adsorption capacity of clayey sand, two types of adsorbents (zeolite and rice husk ash ) were added to the base composition and their behavior were investigated in the case of Lead and Zinc contamination. The results revealed that replacing the rice husk ash and zeolite adsorbents in the sand combination with 20% kaolinite clay significantly reduced the concentration of lead and zinc nitrate in the solution. Replacing 15% of rice husk ash with kaolinite heightened the absorption of lead nitrate and zinc nitrate by 228.8% and 291.6% in kaolinite sand. It was also found that adding nitrate to kaolinite increased the liquid and plastic limits. According to the results, in kaolinite, the value of the liquid limit rose from 49.8 to 59.1 upon elevating the concentration of lead to 5000 ppm, while the plastic limit also increased from 31 in the non-contaminated state to 36.4 in 5000 ppm in the infected state. According to obtained results, the dispersed structure is formed by increasing the concentration of lead nitrate in composition of sandy clay with low plasticity adsorbent; thus, shear resistance decreased. Changing in type of clay minerals to high plasticity cause the different trend in shear resistance parameters. Increasing the concentration of lead nitrate in bentonite composition, lead to flocculated structure be formed and shear strength increased.

Due to the expansion of cyberspace in the context of internet use and public access to this platform, many stores try to use the online sales platform to eliminate geographical zones restrictions and the number of intermediaries. This approach has many other advantages such as reducing completed costs, lower shipping costs and faster speed of product delivery, etc. Proper evaluation and suppliers ranking plays an important role in increasing the productivity of these types of stores. This research provides an approach to evaluate and rank suppliers in digital stores using a combination of two multi-criteria decision-making (MCDM) techniques called Analysis Hierarchy Process (AHP) and TOPKOR. First, the effective criteria in evaluation and the ranking of suppliers in digital stores are identified and their weights are determined using AHP technique. Then, the score of each supplier in each criterion is determined. Finally, the suppliers are ranked based on TOPKOR technique. The results not only show the final rank of suppliers but also identified 8 criteria for evaluation and ranking the suppliers. Moreover, the results show the criteria of support, easy access and flexibility are the most important in evaluating and ranking digital stores’ suppliers, respectively.

The concrete jacket method is a common method used in retrofitting buildings. Although this method has many advantages, engineers criticize it due to an increase in the structure's weight. In the present study, lightweight concretes containing silica nanoparticles (SNPs) and glass fibers (GF) have been used in concrete jackets to strengthen concrete beams. Several reinforced concrete (RC) beams were constructed and retrofitted using the proposed lightweight concrete jackets and their response to four-point loading was evaluated. The SNPs amount in the lightweight concrete jackets was 0, 2, 4, and 6% by weight of cement and the amount of GF was 1.5% by volume of concrete. Load-deflection curves were extracted and the response of the beams was examined by parameters such as crack load, yield load, maximum load, energy absorption capacity, and ductility. The proposed lightweight concrete jacket containing 1.5% of GFs in which 0, 2, 4, and 6% of SNPs were used, increased the energy absorption capacity by 33%, 54%, 61%, and 62%, respectively. The presence of SNPs in lightweight concrete reinforced by GFs leads to the filling of small cavities in the concrete. Also, the bearing capacity of the retrofitted RC beams increased with an increase in SNPs in the concrete jacket. A portion of this increase can be attributed to an increase in tensile and compressive strength of the proposed concrete, and the other part can be attributed to the effect of SNPs on the surrounding surfaces of the main beam and jacket.

Structures close to causative earthquake faults may exhibit substantially different seismic responses than those recorded away from the excitation source. In the near-fault zone, long duration intense velocity pulses can induce unexpected seismic demands on isolated buildings. This study investigates the performance of a five-storey building frame isolated with a shape memory alloy based friction pendulum system (SMA-FPS) under near-fault excitations. The effectiveness of SMA-FPS is quantified by comparing the same isolated structure subjected to a friction pendulum system (FPS). Parametric studies, optimal analysis and numerical simulations are carried out on the structural parameters of the isolation systems. For this, the particle swarm optimization (PSO) method is used to acquire optimal characteristic strengths of SMA-FPS. The transformation strength of SMA and frictional coefficient are selected as two design variables to minimize the top storey acceleration, which is used as the objective function to optimize the seismic reduction efficiency of SMA-FPS system. The optimal seismic response of the structure isolated by SMA-FPS achieves superior performance over FPS under near-fault excitations. Moreover, the study reveals that the optimal SMA-FPS system significantly reduces the bearing displacement as compared to the FPS system. Finally, the computational results are validated with numerical simulation performed in SAP2000 which provides the consistent result.

Spinning reserve (SR) is one of the most prevalent methods for balancing grid uncertainties, such as generator faults, to maintain grid reliability. Literature review shows that several deterministic as well as probabilistic methos have been proposed for determining SR. It is always a challenge for a system operator to decide which approach better from security and reliability point of view. This is important because the allocated SR may provide in some cases a misleading sense of confidence with respect to safe, secure, reliable and economic operation of power systems. This paper presents a cost-based risk index approach for assessing the spinning reserve requirements in a power system. To that end, the performance of spinning reserve is classified in three types, namely, not-effective, partially-effective, and not-meeting-load. Then probability of each type and its consequences are subsequently computed and finally that the risk associated with any spinning reserve value is determined. It is shown that one might consider various spinning reserve values for an operating condition (randomly or using approaches proposed in literature), then calculate risks associated with each value, and finally use the calculated risk indices to determining the optimal level of spinning reserve. As an example, we have shown that in the studied network with 6600MW load, maintaining 240MW SR will increase cost of 1MW hour energy by $0.154 while the optimal value of 200MW SR will increase cost of 1MWhour energy by just $0.126. This paper initially focuses on providing a measure of the quality of an ex-ante specified spinning reserve, latter on the flowchart of using the proposed approach for determining optimal level of spinning reserve is presented. The proposed risk index can also be used for comparing different deterministic as well as probabilistic approaches presented in literature for spinning reserve requirements.

The process quality is described by one or more important factors called multivariate processes. Contingency tables used to demonstrate the relevance between these factors and modeled by log-linear model. There are also two types of statistical variables that are nominal and ordinal. In this paper, the variables are ordinal and two new control charts have been used to monitor the process of analyzing subscribers' consumption. These two multivariate ordinal chart are the MR chart and the multivariate ordinal categorical (MOC) used to monitor processes based on the ordinal log-linear model in Phase II. In addition, with a real numerical example, about analyzing the internet usage of mobile subscribers, two control charts are drawn and compared with each other in terms of average run length. In this case, we focus on customer behavior and in real action, by marketing department, changing in data consumption has been seen and analyzed. The study of the two proposed charts was performed using simulation based on real example in different situation, and the MOC performed relatively better.

Novel catalyst called super active catalyst for the production of high density polyethylene (HDPE) pipes grade 100 was prepared and localized for the first time in Iran. The purpose of this paper is to evaluate the performance of the new catalyst and compare it with Finix-112 catalyst which is a commercial catalyst for the production of HEPE grade 100. Extensive experiments were performed on the physical and mechanical properties of the product using both catalysts including melt flow index, particle size distribution, volatility, density, bulk density, scanning electron microscope-energy dispersive x-ray analysis, charpy impact strength. Comparison of the results showed that the hydrogen responsibility performance of the product with super active catalyst is 19%, charpy impact is 16.7% and pressure condition in first reactor about 28% was better than product with Finix-112 catalyst. Home-made super active catalyst can be a good alternative to imported finix-112 catalyst and save a considerable amount of foreign currency.

The ground differential (GD) relay is used to detect internal ground faults on the power transformer windings and terminals. In fact, this relay is employed as a complement to the phase differential (PD) relay. However, its stability is affected by magnetic saturation in current transformers (CTs) cores so that the spurious differential current caused by CT saturation may lead to the relay malfunction. In this paper, by modifying the restraining current definition in a conventional method, an adaptive restrain method is proposed. To evaluate the proposed method performance compared with conventional method, a real 230/63 kV power transformer under a large number of internal fault, external fault and in rush current cases are simulated in PSCAD/EMTDC environment. It is worth noting that Jiles-Atherton (JA) model is utilized to simulate CTs. MATLAB software is used to implement and analyze these methods using obtained simulation. Obtained results show that the proposed method is quite superior to the conventional method, despite its simplicity.

Three-phase back-to-back converters are widely applied in various industrial, commercial, and domestic applications, such as AC motor drives. Due to the non-sinusoidal voltages they generate, a common mode voltage (CMV) appears, leading to problems in electrical drive systems and high-frequency applications. The CMV and rapid voltage changes can cause serious problems, including leakage currents flowing through the parasitic capacitors inside the motor, electromagnetic interference, shaft voltage, and bearing currents that reduce the motor’s lifespan. In general, research to reduce these effects is divided into two methods modifying the drive system’s physical structure or improving the inverter’s control algorithm. Pulse Width Modulation (PWM) methods are commonly used in control algorithms of converters to reduce the CMV. However, adding pulse amplitude modulation to the PWM helps reduce the CMV. The technique of simultaneous pulse width and amplitude modulation of space vectors is proposed in this paper to reduce the CMV and its destructive effects in drive systems. The proposed technique is based on the elimination of zero vectors and the inherent reduction of DC link voltage by amplitude modulation leading to a further reduction of the CMV; The obtained results of applying the proposed strategy to a three-phase back-to-back NPC converter with 738-watt steady-state operating point power showed the system’s sufficient behavior with the efficiency of 98.62 percent. Finally, the transient performance of the converter from no-load to full-load condition ensures its sufficient behavior for industrial applications.

Because of the ability of stem cells to self-renew and differentiate into cardiomyocytes, they are optimal cell sources for cardiac tissue engineering. Since heart cells experience cyclic strain and pulsatile flow in vivo, these mechanical stimuli are essential factors for stem cell differentiation. This study aimed to investigate the effect of a combination of pulsatile flow and cyclic strain on the shear stress created on the embryonic stem cell layer with a elastic property in a perfusion bioreactor by using the fluid-solid interaction (FSI) method. In this study, the frequency and stress phase angle had been assumed as a variable. The results show that the maximum shear stress at frequencies of 0.33, and 1 Hz and with frequency differences in cyclic strain (0.33 Hz) and pulsatile flow (1 Hz) are 0.00562, 0.02, and 0.01 dyn/cm², respectively. Moreover, in the stress phase angles 0, , and , the maximum shear stress are equal to 0.00562, 0.009, and 0.014 dyn/cm², respectively. The results of this study can be an effective step in developing cardiac tissue engineering and a better understanding of the effects of mechanical stimuli on stem cell differentiation.

The essence of the present work is to study the rheological properties of the in-house prepared magneto-rheological (MR) fluids in the pre-yield region since the rheological properties play a vital role in better understanding of vibration damping capabilities of MR fluids. In the present work, two different compositions of MR fluid samples were prepared with 24 and 30 volume percentages of carbonyl iron (CI) particles. Prepared MR fluid samples contain CI particles as a dispersive medium, silicone oil as a carrier fluid and white lithium grease as an anti-settling agent. The oscillating driving frequency and amplitude strain sweep tests are performed to investigate the rheological properties within the pre-yield region. The influences of driving frequency, strain amplitude, magnetic field and CI particles volume percentage on the rheological properties of the prepared MR fluids were assessed.  The linear viscoelastic region of the prepared MR fluid sample was identified and the yield strain obtained was around 0.371%. It is observed that the volume percentage of CI particles in the MR fluid strongly influenced the rheological properties.

Wire-Electric Discharge (WED) Machining is one of the most suitable machining techniques for machining hard-to-cut materials such as Titanium, with precision. It is of utmost importance to optimize the control parameters to achieve the desired levels of machining performance characteristics. Considering this goal, this research investigates the effects of current, pulse on time (Ton) and pulse off time (Toff) on the material removal rate, surface roughness and kerf width of WED machined Ti-6Al-4V. The results of optimization showed that, current – 5.19 A, Ton – 20 µs, Toff – 30 µs, is the optimized settings for machining of Ti-6Al-4V alloy using molybdenum electrode for the best machining performance. Based on the analysis of grey relational grades, the order of influence of the control parameter is ranked as: Ton – I, Toff – II and Current – III. The efficacy of GRA based approach was evaluated through confirmation experiments wherein the theoretical predictions showed errors < 3%.

Concrete is a material that can easily absorb nuclear radiation, and in this process, the density of concrete is an essential factor in absorbing the rays. Therefore, due to performance limitations and thickness, heavyweight concrete is used. In this study, serpentine coarse aggregates (SCAg) and serpentine fine aggregates (SFAg) were used as a substitute for sand and gravel in heavyweight concrete containing lead slag to protect against gamma rays. Determination of mechanical properties (compressive strength, tensile strength, and ultrasonic pulse velocity), physical properties (water absorption and electrical resistivity), and shielding properties (shielding against gamma rays) were among the main objectives. The results indicated the positive effect of SFAg and SCAg on the shielding properties of concretes against gamma rays. The replacement of SFAg and SCAg with natural aggregates increased the density of the samples, which resulted in an increase in 3.8 to 42.9% in the linear attenuation coefficient against gamma rays. SFAg has a significant effect on gamma-ray attenuation, especially when these materials are made of high-density minerals, due to their property of reducing the pores in concrete.

In this paper, a bionic perception method of navel orange plucking position based on Fmincon and Proportional Differential (PD) angle control is proposed to solve the problems of wind disturbance and green branches in dynamic unstructured environment. Different from these algorithms that limited to two-dimensional images, this method realizes picking position perception in three-dimensional. Meanwhile, the perception method and the picking robot control algorithm are achieved simultaneously. Firstly, an optimal solution model of the global target rotation angle of the control system based on Fmincon is established to solve the angle optimization problem of robot target approach motion. Secondly, a bionic perception system of plucking position based on PD angle control is constructed to solve specific perception problems. Finally, a joint simulation platform for picking robots based on Solidworks, Adams, and Simulink is given; the validity and accuracy of the algorithm were verified. The experimental results show that the picking accuracy rate is 95%, the angle error of each mechanism and the displacement error are less than 0.5 degrees and 10mm, respectively. The total time from the optimized angle calculation to the system's stability is only about 0.33s. This method is suitable for the rapid perception of plucking position and active angle control of picking robots under dynamic unstructured environment.