Showing papers in "International Journal of Engineering - Transactions C: Aspects in 2017"

A Network Design Model for a Resilient Closed-Loop Supply Chain with Lateral Transshipment

Abstract: This paper develops a model for the closed-loop supply chain network design with disruption risk. By considering supply disruption, two factors including extra inventory and lateral transshipment are used as resilience strategies. The main purpose is to reduce the supply chain costs due to the location decisions, quantity of products between different levels and lost sale. Disruption in a supply is assumed completely by different scenarios, and then the problem is formulated by a mixed-integer programming model. Furthermore, a two-stage stochastic approach is implemented to tackle uncertainty. Finally, a sensitivity analysis is carried out to examine the effects of the resilience strategies on the structure of the supply chain and to propose some managerial insight for using the model in real world situations.

Relationship between Pedestrians’ Speed, Density and Flow Rate of Crossings through Urban Intersections (Case Study: Rasht Metropolis) (RESEARCH NOTE)

Abstract: Travels within the city are done in different ways, by vehicle or on foot. Thus, inevitably, a part of the travel is always done on foot. Since intersections as traffic nodes are determinant factor in transportation network capacity, any disruption in them leads to severe reduction in network capacity. Unfortunately, pedestrian behavior has received little attention in Iran. While this is a very important and effective part of traffic engineering. In some cases, pedestrians are the main cause of increasing road users’ delay, therefore, the most important action before anything, is identifying the characteristics of pedestrians. Identifying issues such as speed, volume and density of pedestrians are necessary to control the traffic flow and delay, and can lead to better design of facilities associated with pedestrians. Cases that are studied in this study are: the relationship between speed, density and pedestrians’ flow rate while crossing the street. In this study, the data was collected by filming four intersections in Rasht Metropolis for 15 hours, and the number of pedestrians crossing that were studied was 8489. Two intersections had traffic lights and the other ones had no traffic lights. Then, the relationship between speed, density and volume of pedestrians were obtained by determining the variables of speed, density and volume of pedestrians and using linear and nonlinear regression method and finding the correlation coefficient between the variables. The results showed that for pedestrians, there is a relationship between the flow rate and density with a high correlation coefficient in crossing through crosswalk (R2=0.99) and outside the crosswalk (R2=0.99). But the relationship between speed and flow rate was not significant (crossing through crosswalk, R2=0.29 and outside the crosswalk, R2=0.24); furthermore, speed and density had no significant relationship (crossing through crosswalk, R2=0.36 and outside the crosswalk, R2=0.28).

Modeling and Optimization of Roll-bonding Parameters for Bond Strength of Ti/Cu/Ti Clad Composites by Artificial Neural Networks and Genetic Algorithm

Abstract: This paper deals with modeling and optimization of the roll-bonding process of Ti/Cu/Ti composite for determination of the best roll-bonding parameters leading to the maximum Ti/Cu bond strength by combination of neural network and genetic algorithm. An artificial neural network (ANN) program has been proposed to determine the effect of practical parameters, i.e., rolling temperature, reduction in thickness, post-annealing time, post-annealing temperature and rolling speed on the bond strength of Ti/Cu composite. The most suitable model with correlation coefficient (R2) of 0.98 and mean absolute error (MAPE) 3.5 was determined using genetic algorithm (GA) and the optimum practice condition are proposed. Moreover, the sensitivity analysis results showed the post-annealing temperature with the negative effects is the most influential parameter on the strength of bonding.

Embedded Memory Test Strategies and Repair

Abstract: The demand of self-testing proportionally increases with memory size in System on Chip (SoC). SoC architecture normally occupies the majority of its area by memories. Due to increase in density of embedded memories, there is a need of self-testing mechanism in SoC design. Therefore, this research study focuses on this problem and introduces a smooth solution for self-testing. In the proposed memory test algorithm, the self-testing as well as self-repair mechanisms are incorporated. This scheme repairs the detected faults and is easily integrated with SoC design. Here, an attempt has been made to implement the memory built-in-self-repair (MBISR) architecture to test and repair the faults from the embedded memories. It is little, and it supports at-fast test without timing penalty during its operation. The proposed method is a better alternative in speed and low area overhead. Thus, it plays a significant role in yield improvement.

Parameters Identification of an Experimental Vision-based Target Tracker Robot Using Genetic Algorithm

Abstract: In this paper, the uncertain dynamic parameters of an experimental target tracker robot are identified through the application of genetic algorithm. The considered serial robot is a two-degree-of-freedom dynamic system with two revolute joints in which damping coefficients and inertia terms are uncertain. First, dynamic equations governing the robot system are extracted and then, simulated numerically. Next, an open-loop experiment with finite duration step inputs is implemented on the experimental setup to collect practical output data. Accordingly, a desired objective function is defined as the sum of discrepancy between the experimental and simulated output data. Subsequently, a genetic algorithm is employed to explore the best damping coefficients and inertia terms of the simulation scheme so as to minimize the presented cost function and taking into account the same input data for both simulation and experiment. Finally, the simulated output data based on the identified robot parameters reveal an acceptable agreement with the measured outputs through which validity of the identification scheme is affirmed.

Design and simulation of a moving-magnet-type linear synchronous motor for electromagnetic launch system

Abstract: The Electromagnetic Aircraft Launch System (EMALS) offers significant benefits to the aircraft, ship, personnel, and operational capabilities. EMALS has such advantages as high thrust, good controllability, reusable, etc., as a launching motor, a double-side plate Permanent Magnet Linear Synchronous Motor (PMLSM) can provide high instantaneous thrust. This paper presents the design and analysis of the moving-magnet-type permanent magnet linear synchronous motor (PMLSM). A detailed analytical modeling based on Maxwell’s equations is presented for analysis and design of PMLSM with Halbach array. In order to improve the thrust characteristics of PMLSM, the structural characteristics and magnetic field are analyzed. The results show an enhancement in the motor performance. Finally, we have used 2-D nonlinear time-stepping transient finite element method to demonstrate validity of the analytical analysis and parametric search is used for multi-objective optimization of PMLSM. Using Finite Element Analysis (FEA), the effects of the parameters on the thrust and thrust ripple waveforms are analyzed.

The Integrated Supply Chain of After-sales Services Model: A Multi-objective Scatter Search Optimization Approach

Abstract: In recent decades, high profits of extended warranty have caused that third-party firms consider it as a lucrative after-sales service. However, customers division in terms of risk aversion and effect of offering extended warranty on manufacturers’ basic warranty should be investigated through adjusting such services. Since risk-averse customers welcome extended warranty, while the customers without taking on risk may remain at the level of basic warranty. In this paper, a multi-objective integer nonlinear programming model is presented for integrating the supply chain of after-sales services. In the suggested model, firstly strategies used by the manufacturers in the basic warranty period and the third party’s policy during the extended warranty period, including the development of a new imperfect maintenance approach, are regulated. Then, the effects of these strategies on the desirability of customers with different levels of risk-taking are analyzed. To optimize the model, the scatter search based approach was introduced for extracting set of non-dominated solutions. The results indicated that increasing level of customers’ risk-taking convinces manufacturers to diminish the basic warranty period and the third party can apply less costly preventive maintenance. Key Words: Warranty, Extended warranty, After-sales services, Customers’ risk-taking, Pareto-set solutions, Multi-objective scatter search

Pareto-based Multi-criteria Evolutionary Algorithm for Parallel Machines Scheduling Problem with Sequence-dependent Setup Times

Abstract: This paper addresses an unrelated multi-machine scheduling problem with sequence-dependent setup time, release date and processing set restriction to minimize the sum of weighted earliness/tardiness penalties and the sum of completion times, which is known to be NP-hard. A Mixed Integer Programming (MIP) model is proposed to formulate the considered multi-criteria problem. Also, to solve the model for real-sized applications, a Pareto-based algorithm, namely controlled elitism non-dominated sorting genetic algorithm (CENSGA), is proposed. To validate its performance, the algorithm is examined under six performance metric measures, and compared with a Pareto-based algorithm, namely NSGA-II. The results are statistically evaluated by the Mann–Whitney test and t-test methods. From the obtained results based on the t-test, the proposed CENSGA significantly outperforms the NSGA-II in four out of six terms. Additionally, the statistical results from Mann–Whitney test show that the performance of the proposed CENSGA is better than the NSGA- II in two out of six terms. Finally, the experimental results indicate the effectiveness of the proposed algorithm for different problems.

Cycle Time Reduction and Runtime Rebalancing by Reallocating Dependent Tasks

Abstract: Business Process Management Systems (BPMS) is a complex information system that provides designing, administrating, and improving the business processes. Task allocation to human resources is one of the most important issues which should be managed more efficiently in BPMS. Task allocation algorithms are defined in order to meet the various policies of organizations. The most important of these policies could be reducing the average cycle time, balancing the resource workload, increasing the product quality and minimizing the production costs. Therefore, choosing an appropriate resource in task allocation algorithms could influence on overall policy of the organization. In heavy load conditions or when the number of human resources is limited, workload balancing can increase the stability of the system. In this paper, a task allocation algorithm is proposed to rebalance the resource workload in runtime while minimizing cycle time by offering dependent pair tasks to resources for concurrent processing. The experimental results show that the combination of previous algorithms with the proposed algorithms would have 4.42% reduction in cycle time in contrast to most efficient state-of-the-art algorithms.

Statistical Analysis of the Railway Accidents Causes in Iran (TECHNICAL NOTE)

Abstract: The occurrences of accidents on the railways are inevitable in today’s world and the factors which may cause it, except the atmospheric and accidental ones, are identified and preventable as well. Therefore, these factors can be investigated and useful actions can be performed in order to reduce these accidents. The main impetus of the present research is the statistical analysis of the causes of railway accidents in Iran. Our achievement illustrates that except the train collision accidents with vehicles, all the accidents vary upon a sixth order curve which means the instability and unpredictability of the railway accidents during the last years. According to the performed studies, it is clarified that the railway accidents during the 10 years from 2000 to 2010 have not had a stable flow and have been under fluctuations and each of the kinds and causes of the accidents has its own contribution to the occurrence of these railway related happenings. Based on the analyses, derailment is the major factor of the various railway accidents and it includes about 55% of these accidents. Damage to people and collisions with non-rail vehicles are placed in the second category. Hereupon, efforts must be made by providing the necessary equipment for the simple access of the people beyond the lines such as pedestrian bridges in order to reduce the railway accidents.

Bi-level Model for Reliability based Maintenance and Job Scheduling

Abstract: Many defects in manufacturing system are caused by human resources that show the significance of the human resources in manufacturing systems. Most manufacturers attempt to investigate the human resources in order to improve the work conditions and reduce the human error by providing a proper work-rest schedule. On the other hand, manufacturer deal with machine scheduling based on demand and work type. The mentioned scheduling would be effective if both are simultaneously implemented; then, we confront integrated human- machine systems which work with minimum cost, machine failure and human errors. Considering this fact, we propose a bi-level mixed integer nonlinear model to minimize the machine scheduling costs such as earliness-tardiness cost and interruption cost in the upper level and human error in lower level according to performance shaping factors (PSFs). Several numerical instances are implemented by the proposed model to show the model effectiveness to obtain the best work schedule for human resources and machines in manufacturing systems.

High Reynolds Viscous Flow Simulation Past the Elliptical Airfoil by Random Vortex Blob

Abstract: In this paper, numerical simulation for a two-dimensional viscous and incompressible flow past the elliptical airfoil is presented by Random Vortex Blob (RVB). RVB is a numerical technique to solve the incompressible, two-dimensional and unsteady Navier-Stocks equations by converting them to rotational non-primitive formulations. In this method, the velocity vector at a certain point can be calculated without considering any grid around it, so the RVB method can be treated as a meshless method. Accordingly, the turbulent flow past a cylinder as well as an elliptical airfoil is investigated. In both cases, the obtained mean time velocities are compared with available numerical and experimental results where an acceptable agreement is observed. Having known the velocity field, by employing momentum balance, the drag and lift coefficients caused by flow past the elliptical airfoil with different diameter ratios and Re=105 are calculated and compared with experimental data where a good consistency is achieved.

The Analysis of Wheel Loader Diesel Engine Crankshaft Failure

Abstract: The main purpose of this study is to review the cause for the crankshaft failure of six-cylinder diesel engine of a wheel loader after passing a short period of time. The failure had occurred after 4800 hours of in-service in the fifth crankpin of the crankshaft. Hardness and tensile tests were carried out to study their mechanical properties. Spectrophotometer machine was used to examine the chemical composition of the crankshaft material. To examine the material microstructure, its defects and the morphology of fracture surface, optical microscopes (OM) and scanning electronic microscopes (SEM) equipped with energy dispersive spectrometry (EDS) were used. The morphology of fracture surface showed that the fracture is of the smooth type and has occurred due to the fatigue. Main origin of the fatigue cracks appeared on the surface of the crankpin might be created by the existence of oil impurities, the impurities on the surface of the crankpin, inappropriate machining on the surface of the crankpin or severe wear and pitting from insufficient lubricating.

A Planar, Layered Ultra-wideband Metamaterial Absorber for Microwave Frequencies

Abstract: In this paper, an ultra-wideband metamaterial absorber is designed and simulated. The proposed absorber is planar and low profile. It is made of a copper sheet coated with two dielectric layers. Each unit cell of the metamaterial structure is composed of multiple metallic split rings, which are patterned on the top and middle boundaries of the dielectrics. The designed absorber utilizes different resonances of the split rings with non-identical parameters. In order to achieve ultra-wideband absorption, dimensions of the rings are designed to represent dissimilar nearby resonant frequencies. An ultra-wide bandwidth of 67% for 85% absorption is achieved. The absorber’s performance is investigated for TE and TM polarizations, and with varying incidence and polarization angles. Ultra-wide band performance of the structure for the case of normal incidence changes to multi-band absorption, with increasing the incidence angle. Electric field distribution of the rings for three low, middle and high frequencies in the absorption bandwidth is simulated and graphically demonstrated. The field distribution verifies that the rings with larger dimensions interact more effectively with low frequency electromagnetic waves, and the rings with smaller dimensions have stronger effects on high frequency waves.

Bertrand-nash Equilibrium in the Retail Duopoly Model under Asymmetric Costs

Abstract: In this paper, the Bertrand's price competition in the retail duopoly with asymmetric costs is analyzed Retailers sell substitute products in the framework of the classical economic order quantity (EOQ) model with linear demand function The market potential and competitor price are considered to be the bifurcation parameters of retailers Levels of the barriers to market penetration depending on the bifurcation parameters are analyzed The conditions of Bertrand-Nash equilibrium in parametric and trigonometric forms are found

Detailed Scheduling of Tree-like Pipeline Networks with Multiple Refineries

Abstract: In the oil supply chain, the refined petroleum products are transported by various transportation modes, such as rail, road, vessel and pipeline. The latter provides one of the safest and cheapest ways to connect production areas to local markets. This paper addresses the operational scheduling of a multi-product tree-like pipeline connecting several refineries to multiple distribution centers under demand uncertainty. A new deterministic mixed-integer linear programming (MILP) model is first presented, and then a two-stage stochastic model is proposed. The aim of this model is to meet depot requirements at the minimum total cost including pumping and stoppages costs. The efficiency and utility of the proposed model is shown by two numerical examples, which one of them uses the industrial and real data.

Multi-objective optimization of stirling heat engine using gray wolf optimization algorithm (technical note)

Abstract: The use of meta-heuristic optimization methods have become quite generic in the past two decades. This paper provides a theoretical investigation to find optimum design parameters of the Stirling heat engines using a recently presented nature-inspired method namely the gray wolf optimization (GWO). This algorithm is utilized for the maximization of the output power/thermal efficiency as well as minimization of the pressure loss. The linear programming technique is employed for analyzing the multi-objective problem and the result is compared with the three individually computed costs of the aforementioned cost functions. The results show that the new meta-heuristic algorithm (i.e. GWO) yields acceptable results in quality compared to the other presented methods such as TOPSIS and Bellman-Zadeh.

Case Mix Planning using The Technique for Order of Preference by Similarity to Ideal Solution and Robust Estimation: a Case Study

Abstract: Management of surgery units and operating room (OR) play key roles in optimizing the utilization of hospitals. On this line Case Mix Planning (CMP) is normally applied to long term planning of OR. This refers to allocating OR time to each patient’s group. In this paper a mathematical model is applied to optimize the allocation of OR time among surgical groups. In addition, another technique is applied to provide an Order of Preference by Similarity to Ideal Solution (TOPSIS) considering different hospital performance measures. Furthermore, robust estimation approach is used to estimate the models' parameters using real data. The proposed model is solved using GAMS software. The results of the study performed in this paper reveal that the proposed methods results in an increase in total hospital operated “value of patients” by 21.5%. This value is defined according to hospital priority and includes moral and ethical considerations. In addition, for each resource, a sensitivity analysis of the findings to the changes is conducted. The results of the sensitivity analysis indicated that the value of the objective function significantly increased via reallocating OR time to surgical groups and/or enhancing the OR facilities to support more surgical specialties.

A Novel Method for Implementing of Time-of-use to Improve the Performance of Electric Distribution Systems: A Case Study

Abstract: Increased electric energy consumption in recent years, associated economic problems, reduced reliability and increased power losses in electric networks. One of the main solutions in smart grids to overcome the mentioned problems is demand response programs. In demand response programs, operators apply time-varying tariffs to consumers, and convince them to change their consumption pattern. Among the demand response programs, the most effective program for subscribers who receive electricity at fixed price is time-of-use (TOU) pricing. This paper offers a new approach to implementing TOU program, which is determining the scheduling and pricing of TOU tariff simultaneously taking into account the objectives of smoothing the load profile, reducing the losses and energy not supplied. The proposed method is simulated in MATLAB, and has been evaluated on an urban distribution network in Yazd Electrical Distribution Company (YEDC) that feeds 35 distribution transformers (20/0.4kV) through a radial feeder. Results show that implementation of this method has only a minor increase in cost and reduction in consumption for subscribers, and makes load profile more smooth, improve reliability and reduce power losses.

An Investigation on the Parameters Influencing the Pounding in Highway Bridges

Abstract: The present aim of this study is to investigate the effect of different parameters influencing pounding in highway bridges. Pounding is the result of a collision between two parts of the deck and/or the deck and abutments at the separation distance during the earthquake. In the present study, the period ratio of the adjacent frames, ground motion spatial variation, and soil-structure interaction were considered as the significant parameters influencing the pounding. Accordingly, 144 different models of bridge were generated by changing characteristics of the piers and spans length, and were subjected to non-linear dynamic analysis. The results indicated that ignoring the effects of soil-structure interaction and ground motion spatial variation led to calculate unrealistic responses in the bridges. Finally, it is found that designing bridges including frames with similar or close period is not regarded as an appropriate solution to reduce the pounding effects in the bridges.

Buoyancy Term Evolution in the Multi Relaxation Time Model of Lattice Boltzmann Method with Variable Thermal Conductivity Using a Modified Set of Boundary Conditions

Abstract: During the last few years, a number of numerical boundary condition schemes have been used to study various aspects of the no-slip wall condition using the lattice Boltzmann method. In this paper, a modified boundary condition method is employed to simulate the no-slip wall condition in the presence of the body force term near the wall. These conditions are based on the idea of the bounce-back of the non-equilibrium distribution. The error associated with the modified model is smaller than those of other boundary condition models available in the literature. Additionally, various schemes to simulate body forces have been studied. Based on the numerical results, the model demonstrating minimum error has been reported. Finally, it has been shown that the present model is capable of simulating the effect of high nonlinearity in the heat transfer equation in the presence of a variable thermal conductivity. This has been accomplished by employing a multi relaxation time scheme to model a Rayleigh-Benard natural convection current in a 2-D domain with high Rayleigh numbers. Previous studies reported that the onset of oscillation occurs at Ra≈30,000 and Pr=6.0. By the modified boundary condition method which is used in this study, the oscillation is removed until at least Ra≈ 45,000 and Pr=6.0. The results show that applying scheme 3 for the current boundary condition yields the least amount of error compared to the semi-empirical correlation. The Rayleigh-Benard convection problem has been revisited in the presence of a variable thermal conductivity and the simulation results remain stable for flows with a large variation of thermal conductivity ( = 0.7) and Rayleigh numbers up to 1,000,000 and Pr=0.7.

Pattern Recognition in Control Chart Using Neural Network based on a New Statistical Feature

Abstract: Today for the expedition of the identification and timely correction of process deviations, it is necessary to use advanced techniques to minimize the costs of production of defective products. In this way control charts as one of the important tools for the statistical process control in combination with modern tools such as artificial neural networks have been used. The artificial neural networks were used to recognize the pattern in control charts in several research. Two procedures were used based on the raw data and feature for training and application of neural network. This paper presented new statistical features besides the investigation of their efficiency by application of a neural network. The simulation results demonstrated the positive effect of the presented statistical feature on neural network performance.

Simulation and modeling of a high sensitivity micro-electro-mechanical systems capacitive pressure sensor with small size and clamped square diaphragm

Abstract: This paper proposes a Micro-electro-mechanical (MEMS) capacitive pressure sensor that relies on the movable electrode displaced like a flat plate equal to the maximum center deflection of diaphragm. The diaphragm, movable electrode and mechanical coupling are made of polysilicon, gold and Si3N4, respectively. The fixed electrode is gold and the substrate is Pyrex glass. This proposed method increased the effective surface of capacitor and the displacement of movable electrode. The size of this sensor is 250×250 µm2 and the thickness of diaphragm is 1µm with 1 µm air gap. According to the results the sensitivity of sensor is 58.5

Buying Group Design Considering the Member’s Interest

Abstract: Enhancing the speed and competition in an exhibition of services and products motivated the companies to provide high-quality products to the customers. One of the effective strategies to reach these goals is to create working groups. These groups can help the companies to improve the quality and exposure of their services along with reducing the costs. This approach is applicable in the healthcare area as well. Group buying is one of the main strategies that many healthcare institutes are trying to control the costs and quality of their products. In this study, considering the objectives of procurement costs, the distance of drugstores and the member's interest to cooperate in a purchasing group is proposed. To optimize the model objectives simultaneously, the LP-Metric goal programming approach is utilized. Finally, the case study of drug's group buying is presented to show the proposed model effectiveness.

Base Level Evaluation in Buildings with Different Foundation Levels by Soil-foundation-structure Interaction

Abstract: The base level is among the effective parameters in determining the seismic force on a structure, if the equivalent-static method is used for analyzing a structure. It is obvious that the base level is located on foundation in buildings in which foundation is built in a single level and there is not any interaction between the structure's walls and the soil; however, in some buildings which have underground part, the foundation is built in two different levels which in turn makes the determination of the location of base level uncertain. Since no relevant recommendation has been provided in the seismic codes, this study tries to remove such uncertainties. For this purpose, the structural models along with foundation and their peripheral soil were modeled by the ABAQUS software and regarding the soil type it was tested by an artificial accelerogram compatible with the spectrum of the code. Two types of soil (stiff and soft) were used in this study. The results indicated that the base level location is considerably influenced by the soil type, the number of entrance columns leading to the underground and the number of stories of the structure.

A Novel Interactive Possibilistic Mixed Integer Nonlinear Model for Cellular Manufacturing Problem under Uncertainty

Abstract: Elaborating an appropriate cellular manufacturing system (CMS) could solve many structural and operational issues. Thereby, considering some significant factors as worker skill, machine hardness, and product quality levels could assist the companies in current competitive environment. This paper proposes a novel interactive possibilistic mixed integer nonlinear approach to minimize the total costs of cellular manufacturing design. The proposed approach is elaborated regarding operation sequence, worker and machine assignments, route and worker flexibility, machine hardness level, worker and machine capacity, worker skill level, and product quality level based on imprecise information. Meanwhile, the product demand parameter because of its nature is defined based on fuzzy setting environment. Then, the interactive possibilistic approach is provided to cope with the existed uncertainty according to the problem environment. Finally, a numerical experiment is considered to show the capability of the proposed approach. The results of the proposed interactive possibilistic model show that the presented approach could assist companies for minimizing their costs and manipulating the machines and workers’ suitability. In this respect, comparing the obtained results from the proposed approach and similar circumstances shows that the proposed model could reduce the total costs by 27.8%.

The Effect of Material Properties on Sensitivity of the Microelectromechanical Systems Piezoelectric Hydrophone

Abstract: In this paper, we present mathematical analyses to consider the effect of material properties on the sensitivity of the Microelectromechanical systems (MEMS) piezoelectric hydrophone and improve the sensitivity by choosing the proper material. The selected structure in the present paper is a piezoelectric hydrophone able to work at low frequencies. The piezoelectric hydrophones are widely used in sonar structure. Sonar systems are used in marine vessels and transportation, military submarines, battleships, etc. Piezoelectric hydrophones work by converting the received sound pressure to electrical signals. This conversion of sonar energy to electrical energy is performed by the piezoelectric material in the structure of the hydrophone. Thus, the applied piezoelectric material has significant effect on sensitivity and performance of the sensor. In this paper, the sensitivity of the sensor has been improved from -201.3 dB to -192.6 dB by choosing the proper material with higher piezoelectric coefficients (PZT-2 instead of PZT-5A).

A Dimensionless Parameter Approach based on Singular Value Decomposition and Evolutionary Algorithm for Prediction of Carbamazepine Particles Size

Abstract: The particle size control of drug is one of the most important factors affecting the efficiency of the nano-drug production in confined liquid impinging jets. In the present research, for this investigation the confined liquid impinging jet was used to produce nanoparticles of Carbamazepine. The effects of several parameters such as concentration, solution and anti-solvent flow rate and solvent type were investigated. So far no analytical and acceptable model has been provided to predict the Carbamazepine particle size in confined liquid impinging jets. In this study the variables affecting the size of the particle became dimensionless using the dimensional analysis then by solving the equation with singular value decomposition method, a simple dimensionless relation was obtained for this process. Moreover, using the genetic algorithm the coefficients of dimensionless parameters were optimally extracted to minimize the error between the model and the laboratory outputs. The determination coefficient of the equation obtained by singular value decomposition method and the improved equation using genetic algorithm were obtained as 0.5291 and 0.5697, respectively. For such a complex experimental system, the accuracy of the obtained equations in spite of their simplicity is acceptable. The obtained results were compared with the results of the neural network model. The results showed that despite the higher precision of the obtained relations by the neural network, the relations obtained by singular value decomposition can be used as a simple method using the dimensionless parameters with acceptable acuracy to predict the particle size in confined liquid impinging jets.