International Journal of Engineering
Volume:35 Issue: 1, Jan 2022

Support Vector Machine classifiers are widely used in many classification tasks. However, they have two considerable weaknesses, Unclassifiable Region (UR) in multiclass classification and outliers. In this research, we address these problems by introducing Probabilistic Least Square Twin Support Vector Machine (PLS-TSVM). The proposed algorithm introduces continuous and probabilistic outputs over the model obtained by Least-Square Twin Support Vector Machine (LS-TSVM) method with both linear and polynomial kernel functions. PLS-TSVM not only solves the unclassifiable region problem by introducing a continuous output value membership function, but it also reduces the adverse effects of noisy data and outliers. For showing the superiority of our proposed method, we have conducted experiments on various UCI datasets. In the most cases, higher or competitive accuracy to other methods have been obtained such that in some UCI datasets, PLS-TSVM could obtain up to 99.90% of classification accuracy. Moreover, PLS-TSVM has been evaluated against ”one-against-all” and ”one-against-one” approaches on several well-known video datasets such as Weizmann, KTH, and UCF101 for human action recognition task. The results show the higher accuracy of PLS-TSVM compared to its counterparts. Specifically, the proposed algorithm could improve respectively about 12.2%, 2.8%, and 12.1% of classification accuracy in three video datasets compared to the standard SVM and LS-TSVM classifiers. The final results indicate that the proposed algorithm could achieve better overall performances than the literature.

Reactive powder concrete (RPC) is a type of ultra-high strength cement composite material. It has advanced mechanical properties and shows high ductility characteristics. Many researches have shown that normal and high strength concrete fails under cyclic stresses at load level below its static capacity. In the present study, the mix design guidelines to produce high strength RPC is provided. RPC with compressive strength of 120, 130 and 140MPa was produced. The mechanical properties are obtained for hardened concrete. The present study focuses on the investigation of reactive powder concrete under uniaxial compressive cyclic loading. The investigation was carried out on cubical and cylindrical specimens. The behaviour of RPC under cylic loads is studied by obtaining the stress-strain characteristics under monotonic loading and cyclic loading. Three main types of tests were performed. Stress-strain envelope curve, common point curve and stability point curves were established under repeated load cycles. The limiting stress values required for design are provided. It was concluded that peak stress of the stability point curve could be regarded as the maximum permissible stress. A nonlinear analytical expression was proposed for the normalised stresses and strain which shows a precise fit with the experimental data. The expression will assist in predicting the cyclic response of concrete required for constructional applications.

This investigation aims to study the effect of Fe2O3,Ni nanoparticles as a reinforcement materials on the mechanical properties of unsaturated polyester (UPR) as a matrix to produce a nanocomposite material using a casting route. Various examinations and tests were conducted to define the characteristics of the manufactured nanocomposite, such as Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive Spectrometry (EDS), and Fourier Transform Infrared Spectrometer (FTIR) analysis. The mechanical tests, including tensile, bending and hardness were performed on samples at the room temperature according to ASTM standards, while the magnetic characteristics were defined by vibrating sample magnetometer (VSM). Fe2O3 nanoparticles were incorporation into unsaturated polyester resin by different weight percentages that vary from 0 wt.% to 20 wt.% and a constant concentration 3 wt.% of Ni nanoparticles. The images of FESEM and EDS evinced the homogeneity of F2O3, Ni nanoparticles into the pure unsaturated polyester resin (UPR). While, the improvement in Young's modulus, tensile strength, bending strength, and hardness was compared with those for the UPR. The improvement was 10.02% in Young’s modulus, 44.08% in tensile strength, 13.55% in bending strength, and strength in hardness. Also, the magnetic properties, such as reidual magnetization (Mr), saturation magnetization (Ms) and coercivity force (Hc) enhanced with increasing the concentration of nanoparticles. The preferred percentage to improve the mechanical properties was found at 15 wt.% of Fe2O3 and then decreased above this concentration, whereas the enhancement in hardness was achieved at 20 wt. % of Fe2O3.

In this research, steel plate-fiber concrete composite jackets (SPFCJ) was used to strengthen the RC beams. The accuracy of the analysis method was evaluated by modeling RC beams fabricated in the laboratory, and a good agreement was observed. Variables in the finite element method (FEM) analysis include the strength class of concrete used in the main beam (15, 20, and 25 MPa), the beam length (1.4 and 2.8 m), the type of jackets (RC jacket, SPFCJ, and CFRP sheet), and jacket thickness (40, 60 and 80 mm). SPFCJ is effective for all three concrete grades and increased the energy absorption capacity by 1.88, 2.07, and 2.25 times, respectively. The bearing capacity of the strengthened beam with 60 mm composite jackets increased by 79 and 20% more than the values corresponding to jackets with 40 and 80 mm thickness. The jacket thickness parameter significantly influences the response of strengthened beams with the proposed composite jackets. Depending on the dimensions and geometric characteristics of the beam, the appropriate thickness for the jacket should be considered, and increasing the thickness can not always improve the beam bearing capacity.

Gel casting, carbothermic reduction, and sintering were used to make a porous alumina-based body containing nickel nano-particles. Effects of dispersant (Tri polyphosphate sodium) amount on gel viscosity, mechanical activation of raw materials, raw materials mixture composition, and reduction atmosphere on the prepared composites and NiO reduction mechanism were investigated. XRD, SEM, and TG-DTA analyses were used to characterize the resulting products. It was found that 2.5 wt % dispersant is an optimum amount for a gel suspension with 50 V% of solid consisting of alumina, graphite, and nickel oxide. XRD results of reduced and sintered product (at 1200-1500 °C) showed that alumina, nickel, and nickel aluminate spinel are present in the prepared composite. SEM images of the composite showed that nickel nanoparticles and porosities with different dimensions are present in the alumina body. The porosity of the composite made with 12 h ball milled-alumina was 48%, while it was 64 % in the sample made with 20 min ball-milled alumina. The results of TG-DTA analyses showed that the reduction temperature and mechanism are dependent on the raw materials’ ball milling time. Thermal analyses revealed that mechanical activation of raw materials decreases the NiO reduction temperature and increases the metallic Ni production.

Diaphragms are a fundamental part of the earthquake-resistant system, and in terms of rigidity, it is essential to transmit dynamic loads on a base of the structure.Also, floor openings on the response of buildings against progressive collapse are issues that have received less attention.In this study, floor opening surfaces and their positions on the progressive collapse potential of steel moment-resisting frame (SMRF) buildings were investigated according to the alternate load path method.Also, to retrofit and rehabilitate the two-way reinforced concrete (RC) slabs against a progressive collapse, two strategies, prestressed concrete slabs and installing carbon fiber reinforced polymer sheets on the surface of the old concrete slab, were proposed and six-story SMRF buildings were simulated using the finite element method. The maximum axial force around the removal column is 20% greater than the corresponding values on the floor opening is in the corner of the plan and the appropriate performance of the prestressed concrete slab leads to the load distribution in the ceiling diaphragm.

Natural gas hydrate is a potential energy source in the near future, and its commercial development can alleviate the global energy crisis. Disturbance of drilling mud invasion on hydrate reservoir can lead to hydrate dissociation, affecting wellbore stability while drilling in clayey silt hydrate reservoirs. In this work, the coupled thermo-hydro-chemical finite element model was developed, and influences of drilling mud properties on hydrate dissociation were investigated. The investigation results show that the hydrate dissociation range around wellbore widens as the mud temperature increases. The final dissociation range caused by drilling mud invasion nonlinearly increases from 3.83cm to 10.57cm when the mud temperature is increased from 17.25℃ to 21.25℃. Therefore, the drilling mud needs to be cooled during preparation in platform. In addition, dissociation range narrows as the bottom-hole pressure increases. Dissociation range decreases from 12.18cm to 7.46cm when the bottom-hole pressure is increased from 14.50MPa to 17.00MPa. Thus, the overbalanced/near-balanced drilling operation is preferred during drilling in hydrate reservoirs, and the underbalanced drilling operation is not recommended. Moreover, the increase of mud salinity exacerbates hydrate dissociation in the near-wellbore region. In view of the prevention of hydrate dissociation in the near-wellbore, it is necessary to confect the drilling mud that with appropriate salinity while drilling in hydrate-bearing sediments.

Friction stir welding process is considering one of those solide state welding techgniqe. FSW process has high residuel stresses, distorsion and corrosion resistance. uktrasonic assisted FSW was optimized using the taghuci techniqe to determine the oprtimum condition of process paramters. Effect of process parameter like the vibration amplutude, traverse speed, and tool rotional speed on the oerformance was ansylzied to achive the maximum joint efficiency. anlysis of variance test was demonstrated using mintab sotware to determine the imoirtant of the process prameter that affect the ultimate tensile strength of FSW joints by detetming the contribution percentage if each paramter. the infunese kf uktrasonic vibration on the UTS is more orofound at high welding speeds, wher acoustic softening can privide FSW process with additional softening and therby, the material flow improved. Taghci analysis has shown that the optimum cobdtion observed for a welding speed of 80m/min, rotional speed of 809rpm, and amplutude of 20um.

To endure strong ground motions in large earthquakes, structures need to be equipped with tools to damp the huge amounts of energy induced by these excitations. Since these buildings often have very low damping capability, the amount of energy dissipated within their elastic behavior phase tends to be negligible. There are various classes of TLDs with different tank shapes, aspect ratios, and mechanisms of action, each with their own properties and features. Another cause of energy dissipation in TLDs, in addition to the viscosity of the liquid, is the base shear force that is applied to the damper’s intersection with the main structure with a phase difference relative to the external excitation, because of the difference between hydrostatic forces exerted on the walls at the two ends of the tank. Therefore, the level of liquid interaction with the damper’s walls is also a determinant of the damping of external forces and thus the seismic response of the structure. The study investigated a new type of TLD with a double-walled cylindrical tank. To examine the effect of this TLD on the seismic response, a series of models were built with different liquid heights in the tank’s inner and outer walls and subjected to several seismic excitations on a shaking table. The results showed that using this type of damper reduced the seismic response of the structures. Also, the reduction in seismic response was found to change significantly with the amount of liquid in the damper.

Solar thermal systems for heating have a high level of reliability. The usage of parabolic trough collectors (PTC) for domestic applications is still quite limited; furthermore, commercial utilization of nanofluids in these applications is rare. The influence of MWCNT nanofluid as a heat transfer fluid on the efficiency of a locally developed parabolic trough collector was examined experimentally. The effect of surfactant on nanofluid stability was also investigated, and it was revealed that nanoparticles could be evenly suspended in base fluid for at least 10 days and less than one month using Triton X-100. Experiments were also conducted to determine the optimal quantity of Triton X-100 surfactant; it is possible to make nanoparticles stable for 28 days in base fluid with the ratio of Triton X-100 to MWCNT as 0.5:1. At 2.0, 3.0, and 4.0 L/min flow rates, MWCNT/H2O is used at three-particle concentrations of 0.1 %, 0.2 %, and 0.3 % by weight. The experiment is carried out under outdoor operating conditions. With 3 L/min at 0.2 wt. %, MWCNT nanofluid achieves a maximum thermal efficiency that is 22 % greater than the water. The findings provide important information about the commercialization of a locally developed PTC.

Uncontrolled mining and the tailings produced can cause significant environmental impacts such as water, air, and soil pollution. In the present study, a contaminated soil of gold mines located in Karnataka state of India was studied to know the geotechnical behavior of this soil as a foundation material and to suggest a suitable soil remediation technique to avoid contamination of surrounding water bodies. The in-situ dry unit weight of soil at the selected locations varied from 15.71 to 18.75 kN/m3. The effective shear strength parameters determined from Triaxial test results were in the range of 4.8 – 8.2 kN/m2 and 19.40 – 29.80, respectively, for the cohesion and angle of internal friction. The soil samples were analyzed for bearing capacity and settlement using GEO5 software tool, and the economical dimensions of the footings were estimated. It was observed that the soil has sufficient bearing capacity, and the settlements are within the allowable range. The chemical analysis of the soil samples showed considerable amounts of heavy metals present in the mined soil. Though the strength of the soil is good, the contaminants in the soil may cause groundwater contamination and damages to the footings. Hence, the soil washing technique as a remediation technique was also studied through column leaching tests using different leaching solutions and found that diluted Hydrochloric acid (HCl) with Ethylenediaminetetraacetic acid (EDTA) can effectively remove the heavy metals from the soil.

Drilling test on cylindrical work-pieces was carried out to analysis effect of various microstructures resulting from heat treatment on the machinability of the Ti-6Al-4V alloy. Chip morphology plays a predominant role in determining machinability and wearing of a tool during the drilling of titanium alloys. For this purpose, Ti-6Al-4V was heat treated in three variant cycles then drilled by 2mm diameter drill at 18.8 m/s speed and 0.1 mm/rev feed rate. Results show that heat treatment can effect on hardness. The SEM results showed that by changing their phase and morphology obtained from diferent heat treatment cycle, the machining conditions change. Increasing hardness led to increases length of spiral chips that indicate easy drilling. At a lower depth of cutting, ribbon chips are more compacted in comparison with samples which have a lower hardness. Drilling temperature was increased by increasing deep hole. Samples with lower hardness had a higher temperature in drilling.

Wireless body area network is an emerging technology that has been able to provide a better experience of mobility and flexibility for humans using tiny and low power sensors inside, outside, or around the body compared to the traditional wired monitoring systems. Due to numerous constraints in size, energy consumption, and security of implant devices in the human body, it is still a significant research challenge to design these systems in a reliable and energy-efficient fashion. To provide quality of service, timely and secure delivery of real-time data needs be done without any loss. This paper attempts to provide a communication protocol in order to upgrade QoS levels in WBANs and reduce energy consumption in sensor nodes. To do so, the EDF real-time scheduling algorithm and its combination with the LLF scheduling algorithm are employed to prioritize sensor nodes for sending data packets. The proposed method could optimize the system performance when it is in the event of an overload and tasks miss their deadlines in a row. The OMNET++ simulation environment is used to evaluate the proposed solution's efficiency which checks packet delivery rate and mean-power consumption evaluation criteria in the sink and sensor nodes. This is done with different numbers of nodes in the network. The results show that the proposed strategy could provide an appropriate improvement in sending and receiving packets for body area networks.

Human activity recognition has been a popular research topic in recent years. The rapid development of deep learning techniques has greatly helped researchers to achieve success in this field. But the researches in the literature, usually ignore the distribution of features in the coordinate space despite its great effect on the convergence status of network and activities classification. This paper proposes a hybrid method based on fuzzy centralized coordinate learning and a hybrid loss function to overcome the explained constraint. The fuzzy centralized coordinate learning induces features to be dispersedly spanned across all quadrants of the coordinate space. This causes the angle between the feature vectors of the activity classes to increase significantly. Furthermore, a hybrid loss function is suggested to increase the discriminative power of the proposed method. Our experiments were carried out on the OPPORTUNITY and the PAMAP2 datasets. The proposed model has been compared with six machine learning and three deep learning methods for activity recognition. Experimental results showed that the proposed method outperformed all of the comparative methods due to the identification of discriminative features. The proposed method successfully enhanced the average accuracy by 14.99% and 2.94% on the PAMAP2 and OPPORTUNITY datasets, respectively, compared to the deep learning methods.

Industry 4.0 focuses on the deployment of artificial intelligence in various fields for automation of variety of industrial applications like aerospace, defence, material manufacturing, etc. Application of these principles to active thermography, facilitates automatic defect detection without human intervention and helps in automation in assessing the integrity and product quality. This paper employs artificial neural network (ANN) based classification post-processing modality for exploring subsurface anomalies with improved resolution and enhanced detectability. A modified bi-phase seven-bit barker coded thermal wave imaging is used to simulate the specimens. Experimentation has been carried over CFRP and GFRP specimens using artificially made flat bottom holes of various sizes and depths. A phase based theoretical model also developed for quantitative assessment of depth of the anomaly and experimentally cross verified with a maximum depth error of 3%. Additionally, subsurface anomalies are compared based on probability of detection (POD) and signal to noise ratio (SNR). ANN provides better visualization of defects with 96% probability of detection even for small aspect ratio in contrast to conventional post processing modalities.

The aim of the reported work is to help design of decenary Multi-Valued Logic (MVL) circuits. This paper reports a work, in which, analog voltage-based circuitry is used to design MVL circuits. In this paper, some analog circuits are reported as elements that can be used in Multi-Valued Logic (MVL) circuitry. This article reported a MOSFET-Based Differential Amplifier (MBDA) as a key element in designing decenary MVL arithmetic unit. Operating voltage range and linearity of the gain are two important characteristics of this element. The operating voltage range for the MBDA is 0V to 5.5V as a output voltage.The achieved linear gain is within the range of 0.1V to 5.3V. Analog inverter and correction buffer circuits are reported based on MBDA. Analog inverter will be used in computational and logical decenary MVL circuits. The correction buffer is designed as an element to eliminate noises and signal drift at the output of the MVL gates and during data transfer.

Human action recognition has been a pioneer research problem among the researchers. Feature descriptors are categorized into two categories: global and local. The disadvantage of global feature descriptors is that global features only give the structural information of the action whereas disadvantage of local descriptor is they give only motion information of the action. As a result, the recognition rate gets affected. To improve the recognition rate, hybrid descriptors are also used. But the disadvantage of hybrid descriptors is that they increase the complexity of the descriptor as both global and local features have to be fused. To overcome both the issues we proposed a new local feature descriptor in terms of modal frequency using silhouette and simplicial elements of a silhouette with the help of Finite Element Analysis (FEA). This local descriptor represents the distinctive human poses in the form of modal frequency. These modal frequencies are subject to the stiffness matrix of the body that is associated with the displacement. The silhouettes of the human body are used for the analysis. These silhouettes are represented into simplicial elements. The modal frequencies of silhouettes are calculated using simplicial elements. These modal frequencies of the silhouette are used as the feature vectors that are given to the Radial Basis Function-Support Vector Machine (RBF-SVM) classifier. The challenging datasets Weizmann, KTH and IXMAS are used for validation of the proposed methodology

In this paper, we will be interested in studying a system consisting of a wind turbine operating at variable wind speed, and a two-feed asynchronous machine (DFIG) connected to the grid by the stator and fed by a transducer at the side of the rotor. The conductors are separately controlled for active and reactive power flow between the stator (DFIG) and the grid. The proposed controllers generate reference voltages for the rotor to ensure that the active and reactive power reaches the required reference values, to ensure effective tracking of the optimum operating point and obtaining the maximum electrical power output. Dynamic analysis of the system is performed under the variable wind speed. This analysis is based on active and reactive energy control. The new work in this paper is to introduce theories of genetic algorithms into the control strategy used in the switching chain of wind turbines, to improve performance and efficiency. Simulation results applied to genetic algorithms give greater efficiency, impressive results, and stability to wind turbine systems compared to classic PI regulators. Then, artificial intelligent controls, such as genetic algorithms control, are applied. . Results obtained, in Matlab/Simulink environment, show the efficiency of this proposed unit.

The beam-column connection plays an important role in the building structure, especially when the load is cyclic. The main problem that must be solved is the beam and column connection panels. The purpose of this study was to analyze the characteristics of the hysteresis loop of the displacement load relationship with the control displacement of the precast beam-column connection due to cyclic loading. The research method used is the experimental method with a measurable object design test and a special testing method. The results of this study indicate that normal concrete has a compressive strength of 26.43 MPa, while grouted concrete has a compressive strength of 36.97 MPa. The findings of this study also show that the bond stress grouted concrete increases by 102.4% from normal concrete for D13 diameter screw reinforcement, while for D16 diameter, the adhesive stress increases by 51.63%. The findings of this study also show that in the ultimate condition, the load obtained in the tensile load is 13.58 kN with a displacement of 87.58 mm, while the compressive load is 12.62 kN with a displacement of 88.30 mm. This study concludes that the behavior of precast beam-column joints with dowels is stronger in resisting cyclic loads.

A new type of innovative composite shear wall (concrete-filled cold-formed steel shear wall or CFCSW) is proposed, composed of cold-formed channel sections arc-welded together by 20 mm length of welds and filled with concrete. The main study of the CFCSW focuses on the overall behavior, ultimate load capacity, stiffness and ductility. Three specimens of CFCSW with an aspect ratio of 1.0 are tested under lateral monotonic load. Three-dimensional finite element models are developed and benchmarked with the experimental results. The validated models are used to carry out parametric studies to determine the influence of the parameters on the performance of the CFCSW. The parameters are the height, steel plate thickness, weld spacing and concrete thickness of the CFCSW. The experimental and finite element modeling results indicate that increasing the weld spacing from 105 mm to 211 mm improves the stiffness, ductility and load carrying capacity, and similarly, providing holes inside the wall increases the stiffness, ductility and peak strength of the CFCSW. The ultimate capacity of the CFCSW is most influenced by changing the height of the wall and least influenced by varying the concrete thickness of the wall.

In this paper, we will be interested in studying a system consisting of a wind turbine operating at variable wind speed, and a two-feed asynchronous machine (DFIG) connected to the grid by the stator and fed by a transducer at the side of the rotor. The conductors are separately controlled for active and reactive power flow between the stator (DFIG) and the grid. The proposed controllers generate reference voltages for the rotor to ensure that the active and reactive power reaches the required reference values, to ensure effective tracking of the optimum operating point and obtaining the maximum electrical power output. Dynamic analysis of the system is performed under the variable wind speed. This analysis is based on active and reactive energy control. The new work in this paper is to introduce theories of genetic algorithms into the control strategy used in the switching chain of wind turbines, to improve performance and efficiency. Simulation results applied to genetic algorithms give greater efficiency, impressive results, and stability to wind turbine systems compared to classic PI regulators. Then, artificial intelligent controls, such as genetic algorithms control, are applied. . Results obtained, in Matlab/Simulink environment, show the efficiency of this proposed unit.

Shape memory alloys (SMAs) are functional materials that feature shape memory effects and super-elasticity. These features have made SMAs more efficient materials for reinforcement and improvement of the stability of a structure. The present study aims to investigate the effect of the local post-tensioning with SMAs to improve the load-carrying capacity of tapered steel industrial sheds. For this purpose, ABAQUS software was used to predict the flexural strength and load-bearing capacity of the alloys. The effects of the diameter and the post-tension force applied to the SMA tendons were investigated. The results showed that the external post-tensioning using SMA tendons is an effective way to increase the load-carrying capacity of industrial sheds. The steel and SMA tendons caused a 36% and 60% increase, respectively in the maximum load capacity of the frame. The performance of the sheds was improved by local post-tensioning, which can reduce the weight of the structures.

Productivity and heat transfer in the stepped solar still by varying the glass cover angle and steps height were investigated numerically. Mass, momentum, energy, and diffusion equations were used for simulating the distillation process in order to obtain the productivity and heat transfer coefficient. Further,the numerical simulation validated by existed experimental data. Simulation results indicated the highest freshwater production in comparison with experimental set up condition, which is at the step height 4cm and glass cover angle 60.23◦, belongs to the step height of 5.5cm with 1400 mL/m2hr, namely 91⁒ increase and much less for the step height of 1cm with 350 mL/m2hr, namely 52⁒ decrease. Most increase in Nusselt number obtained for the angle of 55◦ with Nu=12.03 with 29⁒ increase and much less for the angle of 65◦ with Nu=8.16 with 12⁒ decrease. In addition, most and less variation of the heat transfer coefficient obtained for the step height of 5.5cm with hc=4.04 W/m2 K, with 39⁒ increase and for the step height of 1cm with hc=2.18 W/m2 K, with 24⁒ decrease, respectively.

Shallow stiffened footing, in particular the Vierendeel typology, are considered as a design techniques for structures on expansive soils which have proven their success as challenging solutions; combining economy and safety. The current study is investigating an analytical model for preminiraly design of strip footings for light structures on expansive soils, in particular the Vierendeel beam. The developed model is used to calculate, through soil–structure interaction analysis, the algebraic expressions for the bending moment and the footing displacement at any point on the footing. The method is based on a simplification of the clayey ground reaction (Pi) and structure geometry and is derived from an integration of the beam-on-Winkler mound equation. The analytical model is then used to assess the effect of the structure loads on the contact state between the structure and the clayey ground (full or partial contact) as well as the impact of this contact state on the value of the maximum bending moment inside the beam. The results underlines the influence of the construction load on the contact state between the foundation and the swelling soil. The results shows that the bending moment in the footing strongly depends on the contact state between this footing and the clayey ground.