International Journal of Engineering
Volume:35 Issue: 2, Feb 2022

Today, planning and scheduling problems are the most significant issues in the world and make a great impact on improving organizational productivity and serving systems such as medical and healthcare providers. Since operating room planning is a major problem in healthcare organizations, the optimization of medical staff and equipment plays an essential role. Thus, this study presents a multi-objective mathematical model with a new categorization (preoperative, intraoperative, and postoperative) to minimize operating room scheduling and the risk of using equipment. Time constraints in healthcare systems and medical equipment limited capacity are the most significant considered limitation in the present study. In this regard, since the duration of patient preparation and implementation of treatment processes occur in three states of optimistic, pessimistic, and normal, the introduced parameters are examined relying on a fuzzy uncertainty analysis of the problem. Hence, the model is measured in a real numerical solution sample in a medical center to evaluate and confirm the proposed mathematical model. Then, two meta-heuristic algorithms (NRGA and NSGAII) are implemented on the mathematical model to analyze the proposed model. Finally, the research results indicate that the NSGA-II is more efficient in the operating room scheduling problem.

To improve productivity and quality of machining process using Electrical Dischagre Machining (EDM), a lot of electrodes such as coated and alloy electrodes has been applied. Study on multi-objects optimization in EDM with coated electrode will increase number of application of this field into practice. In this study, material removal rate (MRR) and surface roughness (SR) in Electrical Dischagre Machining using Niken coated aluminium electrode were optimized simultaneously using Taguchi - AHP – Topsis methods. Technological parameters including Peak Current (I), Gap Voltage (U) and pulse on time (Ton) were investigated. Titanium alloy (Ti-6Al-4V) was selected as workpiece in experimental process. The results show that combination among Taguchi - AHP - Topsis methods is suitable to solve multi-objects optimization in EDM. The optimized technological parameters are I = 30A, Ton = 500 µs, U = 50 V and optimized quality criterias are MRR = 0.17 mm3/min and SR = 8.76 µm.

The phase-locked loop (PLL) is applied in grid-tied systems to synchronize converter operation with grid voltage, affecting converter stability and performance. Synchronous reference frame PLL (SRF-PLL) is a popular grid synchronization method due to its simplicity and reliability. Normal SRF-PLL cannot suppress DC offset, causing basic frequency and phase oscillations. When a grid is irregular, its bandwidth should be reduced to ensure acceptable disturbance rejection without sacrificing detection speed. To improve phase-angle detection accuracy and speed, the researchers modified the pre/in-loop filtering stage in advanced PLLs.The capacity to deliver improved dynamic response and reduced settling time without compromising system stability or the ability to eliminate disturbances is a major issue for PLLs. Among different control methods, SOGI-FLL (second-order generalized integrator-based frequency locked loop) had the best performance. It tracks grid voltage frequency precisely even when there is sag, swell, harmonics, frequency fluctuations, etc. In the event of a dc offset, the calculated frequency incorporates low-frequency oscillations. A modified second-order generalized integrator frequency-locked loop (MSOGI-FLL) is presented in this work to address grid voltage anomalies of all types, including dc offset. Using the Waijung Block-set of MATLAB/Simulink, a Modified SOGI-FLL is realized and evaluated by applying abnormal grid voltage situations using a low-cost DSP-based STM32F407VGT microcontroller. The results demonstrate MSOGI-better FLL's performance in harsh circumstances.

To improve the structural stability of the ecological slope planting shrubs on both sides of the road is a common phenomenon in highway engineering. The shrub for improving the structural stability plays an important role in the anti-scouring resistance and erosion resistance of the road slope. Although previous studies have focused on the relevant content, the reinforcement ability of different shrubs is rarely quantitatively compared under the same road conditions. Through the field investigation, we found three common slope structural stability protection shrubs. The three shrubs are Amorpha fruticosa Linn. (AFL), Syringa oblata Lindl. (SOL) and Forsythio mandshurica Uyeki. (FMU). The results shown that the single root withdrawal force of three shrubs was proportional to the size of diameter (from 0.6-6 mm). Under the same root diameter conditions, AFL also had the highest single withdrawal force at the slope of 60°. Morover, the morphology traits of the fine root (<1mm) and soil properties affecting soil reinforcement were considered in this study. The mean specific root length, individual length and surface area, and mean diameter of fine roots in different slopes were higher for AFL and SOL than for FMU, especially for high root orders (the third to fifth root orders). These results suggested that the root system traits of AFL and their impact on soil properties would enable more effective consolidated slopes structure than SOL and FMU, revealing that planting AFL might be a better way for enhancing ecological slope structure stability.

In this study, the calcium carbonate from onyx stone used as a pore-forming agent in the ceramic membrane of kaolin, zeolite, and silica xerogel composites has been investigated. Four different membrane samples were prepared with varying onyx stone content from 5 wt.% to 30 wt.% into composite and then the prepared samples were sintered at 1200oC. The structural properties of the prepared sample was investigated in detail using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), and N2 adsorption-desorption isotherms. The removal performance of the membrane has been successfully tested during coconut sap treatment. It has been found that the prepared samples have a porous structure made up of interconnected pores and their volume fraction depends on onyx stone content. The sample with the onyx stone content of 30 wt.% provides the largest volume fraction of homogeneously interconnected pores and its presence demontrates the largest value for sap permeate flux and the flux rate in the initial phase. The pores formed in this produced membrane provide favorable conditions for the removal of the non-sugar impurities in the coconut sap

In this research, steady-state Mixture and Eulerian-Eulerian method for liquid-gas parallel flow ejector have been examined. The simulation demonstrated that the Mixture model simulation represents better and efficient. The Eulerian-Eulerian model needed longer computational time and had a complexity to achieve the optimal convergence. However, both methods' performances were shown slightly similar. The models indicated a difference of about 6% in the flow rate ratio, their pressure diagrams nearly coincide, and their velocity parameter varies by 7% by comparing to the existing experimental data. Additionally, the Mixture model results appropriately conformed much better to the experimental data. So, the Mixture model was chosen for futher parametric study. Simulation results indicated that the flow rate ratio decreases by increasing the throat's cross-sectional area, and the flow rate ratio increases by increasing the nozzle's cross-sectional area. In this regard, e.g., the flow rate ratio of ejector by increasing pressure from 70 to 80 kPa, the air inlet increases up to 94%, and by increasing ejector outlet pressure, the flow rate ratio reduces such that no suction can be observed at 160 kPa. Consequently, in the 150 kPa pressure ratio, the flow rate ratio was reduced by almost 100%.

Data mining is one of the key concepts to discover hidden knowledge from available data. Along with the data mining, data analytics is a field to analyze and process data in a scientific and cognitive angle. It is more helpful to convert knowledge to actionable knowledge for accurate decision making. Data Stream Mining is another challenging area than normal Data Mining due to its dynamics. Dynamics of data in a stream includes changes in data frequency, volume and nature. This paper focuses on the behavior of data mining of machines in process/manufacturing industries. In general, such data is continuous numerical and time series data captured by various industrial sensors. By nature, equipment or machinery behavioral changeover time. It requires calibration/replacement before failure of machinery. By analyzing data, one can find the behavior or state change. To identify that, dynamic models are required to be built using data mining and data stream mining. Thus, we are following a semi-novel approach for building such models using “Ensemble of Unsupervised Incremental Learning" method. Results show how the existing methods are different from the proposed method. This method can be applied for any other domain like image/audio/video or text mining also.

The durability of concrete subjected to an aggressive environment is a major issue faced by constructional engineers. Many researchers have tried to evaluate the durability characteristics of concrete against aggressive fluids. Amongst the fluids, compounds of sulphuric acid and chlorides cause massive deterioration in concrete. Reactive powder concrete (RPC) is a type of ultra-high-strength cement composite. In the present study, an effort is made to assess durability properties of RPC. The RPC with compressive strengths 110MPa, 120MPa and 130MPa have been produced. Acid immersion test, salt crystallization test and chloride ion penetration tests have been carried out to assess the degradation of concrete. The samples are exposed to sulphuric acid solutions over a period of 60 days with concentrations varying from 0.5% - 2%. The salt crystallization tests were carried out by immersing samples in 14% Na2SO4 solutions. Visual observations and deterioration in terms of mass and compressive strength reductions are recorded. The RPC shows higher resistance towards the crystallization of salts. A significant amount of weight loss and strength loss is observed for the samples exposed to higher concentrations of sulphuric acid. A negligible amount of chloride ion penetration is observed.

Every year earthquakes occur in various regions in Indonesia because Indonesia is located near earthquake faults. The cyclic lateral loading test in the laboratory has been widely used to simulate lateral loads caused by earthquake events. This research is an experimental study on the behavior of prefabricated foam concrete as an infill wall against lateral cyclic loads. Prefabricated foam concrete was used in this study to make it an alternative to brick and autoclaved lightweight concrete (ALC) blocks that have been widely used as infill walls. This study analyzes the relationship between performance levels, lateral loads and drifts ratio on RC infilled prefabricated foam concrete. Lateral cyclic loading with displacement control method was applied to evaluate the structural behavior where the test refers to ASTM E2126-02a. This study adopts FEMA 273, which regulates the performance levels to be achieved by the structure of a building. The results showed that at performance levels Operational Level (OL), Immediate Occupancy (IO) and Life Safety (LS), the RC frame infilled with prefabricated foam concrete blocks had a drift ratio of 0.2%, 1.2% and 2.4%, respectively. Damage to the RC frame infilled with prefabricated foam concrete blocks was similar to the masonry infilled RC frame.

The soil remediation at a contaminated site requires knowledge of contaminant transport parameters and processes. This paper presents the determination of transport parameters from column leaching tests in context with two soil remediation techniques i.e., soil washing and immobilization. To evaluate the soil washing technique, the column leaching tests on the polluted soil were conducted with diluted acid solutions of Hydrochloric acid, Ethylene Diamine Tetraacetic acid and Ferric Chloride to evaluate the leaching efficiencies of selected leaching solutions. It was observed that the efficiency of diluted Ferric Chloride solution was higher as it removed the higher percentage of metals from the soil. From these test results, the contaminant transport parameters i.e., retardation factor and dispersion coefficient were determined which are useful to calculate the volume of leaching solution that will be required for soil washing at a site. As part of immobilization study on this soil, the soil was mixed with selected amendments (Lime, Sodium hydroxide and Cement) to increase the pH of the soil to 10 and the retardation factors were estimated through batch leaching test results. The retardation factors of different metals obtained with lime addition were found higher than the other amendments. To analyze the long-term stability of the amended mixtures, the leaching tests were conducted on amended soil samples and the immobilization efficiencies were estimated. It was found that the immobilization efficiencies were higher with lime addition and also concluded that the immobilization effiencies are directly related to retardation factors.

In this study, an attempt was made to optimize the conditions for the transesterification of sunflower oil with methanol, catalyzed by Ca-K/Al2O3 nanocatalysts, using response surface methodology. The variables that were examined were reaction temperature (55, 65 and 75 °C), reaction time (1, 2, 3, 4 and 5 h), catalyst weight base oil (3, 6, 9 and 12 wt%), Ca content (20, 30, 50, 60 and 80 wt%), K content (5, 10, 15 and 20), methanol:sunflower oil molar ratio (3:1, 6:1, 9:1 and 12:1), calcination temperature (600, 700 and 800 °C) and calcination time (1, 2 , 3 and 4 h). Catalyst characterization was done by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform-infrared spectroscopy (FT-IR) and temperature programmed desorption (TPD). The maximum fatty acid methyl esters (FAME) conversion efficiency (biodiesel production efficiency) was 98.3%, at a calcination temperature of 800 oC for 3 h, a methanol-to-oil ratio of 9:1, a reaction temperature of 75 °C, a reaction time of 3 h and a catalyst-to-oil mass ratio of 9%.

The worldwide prevalence of coronavirus disease (COVID-19) and the severe problems in the distribution of medical equipment have led to the modeling of multi-depot vehicle routing under uncertainty in the COVID-19 pandemic. The primary purpose of the proposed model is to locate warehouses and production centers and route vehicles for the distribution of medical goods to hospitals. A robust fuzzy method controls uncertain parameters, such as demand, transmission, and distribution costs. The effect of uncertainty using a neutrosophic fuzzy programming method shows that by increasing demand, the volume of medical goods exchanges and the number of vehicles used to distribute goods increase. This leads to an increase in the total cost of the problem and the amount of greenhouse gas (GHG) emissions. The results also show that using more vehicles reduces staff fatigue to distribute medical products and reduces the prevalence of the COVID-19 pandemic. In the most important sensitivity analysis of the problem on the capacity of the vehicle, it was determined that by increasing the capacity of the vehicle, fewer vehicles are used and as a result, the cost and amount of greenhouse gas emissions are reduced. On the other hand, this has led to a decrease in the prevalence of COVID-19 virus.

Backscatter radiography as a technique can successfully be applied for predicting the pipeline bursting and casing failure. A valid numerical technique will allow predicting these issues without needing to access the outside of the pipelines. Furthermore, this technique has the ability to estimate the shape and depth of damages. It is normally preferred to apply non-destructive testing (NDT) methods which can monitor the status of a pipeline from the internal surface of it without needing to access both sides of it depending on various locations of pipe such as underground or submarine. In the current study, backscatter radiography as an applicable and NDT method to detect locations with potential for pipeline bursting or casing failure was carefully investigated using the Monte Carlo simulation tool. The data obtained by the simulation process showed that backscatter radiography could detect deformations, corroded areas, depositions, creation of load on the casing, lacking proper cementation, excessive pressure inside the pipelines, and other factors which may increase the risk of pipelines bursting or casing failure (in-situ and online) with an acceptable accuracy.

Election prediction has always been of interest to many people. In the last decade, an increasing influence of social networks and the possibility of sharing opinions and ideas has rendered election prediction based on social network data analysis. This paper, drawing on Twitter data and sentiment analysis, uses the proportion of positive messages rate to negative messages rate as an effective indicator for predicting elections. Then, using the aging estimation method, it predicts the values of this indicator in future time windows. The experiments conducted on Twitter data related to the 2020 United States presidential election in a four-month time window indicate that the indicator values and eventually the election results can be predicted with high accuracy.

This work represent a proposed design to supply street lighting power using moving vehicles with an automatic system to guide the fluid flow. In the present design, wind turbines are integrated on the body of the lighting base, which can reduce the construction cost compared to previous designs and use the fluid flow of all vehicles movement with different dimensions to increase system efficiency. Also, present investigation, has been used an automatic system to direct the fluid flow to the wind turbines to increase the efficiency in supplying electricity, which was not installed in the previous designs. Other features of this system include the production of electricity in inappropriate weather and storm conditions, unlike previous designs that had to stop the wind turbine in these conditions to decrease damage. Finally, illuminating the streets and alleys, the stored energy can be used for other purposes, such as charging car batteries and lighting resort stations. Then, comparison between the best design of the third model based on lighting and second model with four vertical wind turbines (VWT) and solar panel (SP), the power generation has increased by 35.55 %. Finally, using an automatic guidance systems (AGS) of fluid flow in the third model based on lighting, the power generation was enhamced by 64.86 %.

The aim of this study is to test the rubberized concrete beams subjected to pure torsional moments. The study focused on the effect of the partial replacement of coarse aggregates with waste rubber chips of different proportions 10%, 20%, and 30% in volume on the beams ultimate torque, and rotation, as well as the ductility index, stiffness, cracking torque, and failure modes. Six specimens of concrete beams as the same size (225×225mm) have been tested. The same steel reinforcement has been applied to four specimens and two without reinforcement. According to experimental findings for reinforced specimens, the ultimate torque for the control beam (without replacement) is higher than beams with replacement rubber but the angle of twist of beams with replacement rubber rose more than the control beam. the ultimate torque decreases compared with the control beam by 4.49%, 10.08%, 13.98%, while the twist angle increases at ultimate torque by 11.16%, 26.79%, 39.69% when the percentage replacement of rubber is 10%, 20%, 30% respectively. When coarse aggregate was replaced with 30% rubber, the ductility index of specimens increased by 39.83%, and ultimate cracking stiffness was lowered by 38.42% as compared with the control beam.

The main purpose of the present research is to investigate the shunting phenomenon in a three-sheet RSW joint using finite element simulation. To this end, a three-sheet resistance spot welding joint was simulated as an electrical-thermal-mechanical coupling problem. To validate the presented simulation, the finite element results were compared with the experimental results, including nugget size and geometric shape in the resistance spot welding joint. Afterwards, the multi-spot welds of three-sheet low carbon steels with the same thicknesses were analyzed considering the sequential distance of 45 mm. Various techniques, including new spot-weld diameter measurement, electrical current density, electrical contact conductivity, and electrode displacement, were used to study shunting effects in the process of consecutive spot welds. The results obtained from different methods have greatly matched each other. Also, finite element results indicated that the assumption of neglecting the sheet deformation effect for low intervals between consecutive spot welds is acceptable. However, it is necessary to consider sheet deformation for distance intervals more than 45 mm.

Wireless sensor networks (WSN) are growing rapidly since the past decade mainly due to its efficiency and Ad-Hoc feature. The data aggregation has been extensively employed in WSN that also impact on the data transferring between the sensor nodes. The security issues, data integrity and confidentiality become vital during the deployment of sensor network in a hostile environment. The entire network comprises of sensors, base stations, gateways and nodes which are connected for the purpose of digital transmission. Many existing works have been evolved to address the security issues in WSN but all focused only on basic security features but lack to obtain reliable and effective results in terms of parameters like energy consumption, packet delivery ratio, and computational cost. This paper focussed on the primary research area of data aggregation and the mode of transmission in an energy efficient way without congestion. To obtain the objective, an integration of Conglomerate ElGamal energy efficient protocol has been employed and the performance of the proposed system are evaluated. Since the resource constraint nodes of the wireless sensor network requires less energy to cope up with limited battery power, the main purpose of the work is to build an efficient security mechanism that enhances the performance of the network with less energy, minimum delay, and maximum throughput. The performance parameters like packet delivery ratio, throughput, estimation of alive nodes and dead nodes for different rounds has been performed in the study. Furthermore, the effectiveness of the proposed system has been compared with state of art methods in terms of residual energy and depicted that deliberates the superior performance of the presented framework

Corrosive fluids such as lithium chloride are often used in liquid desiccant air conditioners. Corrosion in enthalpy exchanger is one of the design problems. Some solutions are studied in this research, and based on them; an experimental setup is investigated. In this design, a counter-flow enthalpy exchanger is used to exchange moisture between the air and the liquid desiccant. First, the inlet air is preheated or precooled by an aluminium heat exchanger. Then, the liquid desiccant is preheated or precooled by thin-walled plastic tubes. By contacting this processed air and liquid desiccant, heat, and mass exchanging occurs. The variation of the air moisture content is investigated in laboratory conditions, and the rate of regeneration and dehumidification is studied. The results indicate that in general, the ambient air moisture content decreased around 20% during the dehumidification process and it enhanced around 14.28% during the regeneration process. Furthermore, the moisture content variation in the dehumidification process improved at least 9.92%, but the regeneration process decreased at least 10.76% compared to the previous study. In addition, utilizing the particle swarm optimization algorithm is desirable to identify the system's transient behavior and obtain the fitting parameters of a curve that is closely similar to the experimental data of the rate of dehumidification and regeneration and the average errors of the fitted curve were 10.43 and 1.52%, respectively.

Cloud computing provides computing resources like software and hardware as a service by the network for several users. Task scheduling is one of the main problems to attain cost-effective execution. The main purpose of task scheduling is to allocate tasks to resources so that it can optimize one or more criteria. Since the problem of task scheduling is one of the Nondeterministic Polynomial-time (NP)-hard problems, meta-heuristic algorithms have been widely employed for solving task scheduling problems. One of the new bio-inspired meta-algorithms is Seagull Optimization Algorithm (SOA). In this paper, we proposed an energy-aware and cost-efficient SOA-based Task Scheduling (SOATS) algorithm. The aims of proposed algorithm to make a trade-off between five objectives (i.e., energy consumption, makespan, cost, waiting time, and load balancing) using a fewer number of iterations. The experiment results by comparing with several meta-heuristic algorithms (i.e., Genetic Algorithm (GA), Particle Swarm Optimization (PSO), Ant Colony Optimization (ACO), and Whale Optimization Algorithm (WOA)) prove that the proposed technique performs better in solving task scheduling problem. Moreover, we compared the proposed algorithm with well-known scheduling Cost-based Job Scheduling (CJS), Moth Search Algorithm based Differential Evolution (MSDE), and Fuzzy-GA (FUGE). In the heavily loaded environment, the SOATS algorithm improved energy consumption and cost saving by 10 and 25%, respectively.

The present study was carried out to investigate and analyze the positionning repeatability introduced by friction variations based on stochastic ellipsoids. A mixed friction model has been developed with improved properties compared to existing standard models. The contact is presented as a multitude of micro contacts whose nature can be of two types: lubricated and solid. This model is experimentally tested on a reciprocating tribometer under extreme friction conditions, with sliding speed varying from 0.1 to 3 m/s and load modified from 40N to 150N to discuss the effect of speed, the effect of nominal contact pressure and the effect of sliding distance on friction parameters. The results showed how this model can be represented as a sum of functions of the relevant states, which are linear and nonlinear in the friction parameters. Thus, these results were used to evaluate the covariance matrix in order to locate the different ranges of errors which have an impact on the repeatability of position.

Improper handling in the food cold supply chain may compromise food safety and reduce quality, which can lead to economic losses and undesirable effects on food accessibility. Therefore, designing an efficient and reliable cold supply chain is extremely important for the company, suppliers, customers, and society. The majority of the traditional studies in the supply chain do not consider the cost of quality (prevention, appraisement, and failure) in supply chain network design. In this study, all dimensions of the cost of quality in a cold supply chain design such as the cost of quality related to suppliers and the cost of distribution service quality are investigated to close the problem to real-world conditions. Moreover, the quality of suppliers, manufacturers, and distributors is simultaneously considered throughout a supply chain with a new approach. To this end, the problem is formulated as a mathematical model for multi-item and multi-period cases considering two objective functions. The first objective function minimizes the total expected costs and the second objective function maximizes the total quality of the supply chain. The proposed bi-objective model has been transformed into a single-objective model by the solution of the parametric method (normalized weighted summation) and solved for a medium-sized instance considering data of a real-world case study. Computational results and analyzes indicate the efficiency of the proposed model as well as the exact solution method available for small and medium scales. The real case study which involves Kaleh Dairy Company is conducted to illustrate the potential of the proposed model and proper sensitivity analyses.

This paper presents a novel channel model based on the edge detection of the interacting objects (IOs) for massive multiple-input and multiple-output (MIMO) systems considering different propagation phenomena such as reflection, refraction, diffraction, and scattering occur at the edges of the IOs. This channel model also uses cluster concepts to model multipath components (MPCs). The time-variant condition of the channel as well as the Doppler effect is considered in this channel model. Also, the non-stationary property of the channel across the array axis can be observed in the simulations. Due to a large number of antenna elements utilized in the massive MIMO systems, the spherical wavefront is assumed instead of the plane wavefront which is used in the conventional MIMO channel model. The central limit theory is also utilized to model the MPCs of each cluster. Furthermore, specific channel characteristics such as channel impulse response (CIR), angle of arrival (AoA) as well as time of arrival (ToA) are extracted in the simulations of the channel.

The performance of many parts in the airplane, aircraft engine and biomedical implants is highly related to their fatigue life, which is clearly depend on the condition of their surface integrity. The geometry parameters of broaching tools have an important influence on the surface integrity after broaching Ti6Al4V alloy. Therefore, this research studies the surface integrity of Ti6Al4V by broaching. The surface integrity is studied at different geometric parameters such as rake angles (α, and α0), clearance angles (β, and β0), and radius of the cutting edge (r0) in two last teeth of the broaching tool that perform chipping. The broached surface integrity is assessed in cases of surface roughness, microstructural, residual stresses, and micro hardness. These results show that the sample broached by tool number 1  (α = 18.4, β = 3.1, α0 = 45, β0 = 9, r0 = 0.02) had higher surface integrity because it was the smoothest surface and the thinnest deformed layer among the other samples. Since the main criterions in selection of the optimal tool are to create the smoothest surface and the least deformed layer depth in the broached sample, tool number 1(α = 18.4, β = 3.1, α0 = 45, β0 = 9, r0 = 0.02) is suggested as the optimal tool.