Engineering Optimization
Fatin Ishraq; Rumaisa Ahmed; Joytun Nisa Joti
Abstract
3D printing or additive manufacturing is a technology in which 3D objects are printed by depositing a thin layer of material layer-by-layer until a final product is produced. In this research work, it has been focused on the fabrication of a Portable 3D Printer for the manufacturing of sample parts by ...
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3D printing or additive manufacturing is a technology in which 3D objects are printed by depositing a thin layer of material layer-by-layer until a final product is produced. In this research work, it has been focused on the fabrication of a Portable 3D Printer for the manufacturing of sample parts by using Fused Deposition Modeling (FDM) process. The primary process parameters such as nozzle temperature, extrusion speed and fill density in addition to their interactions are studied. It has been observed that these process parameters influence the dimensional accuracy and extrusion time of the part produced by the process of FDM. The main objective of the research work is to create a reliable and cost efficient 3-D printer and to minimize the dimensional variation that usually occurs to plastic parts produced by 3D printers. Cartesian mechanism has been used where the print bed moves in the Z direction and the extruder moves in both the X and Y directions. The 3D printing filament that has been used is made of Poly Lactic Acid or Poly Lactide (PLA). The process involved 3D solid modeling to design, 3D printing with coated adhesive applied on the printing platform, measurement of dimensional variation of the printed parts and statistical analysis. Response Surface Methodology (RSM) based desirability analysis has been employed for optimization of FDM process parameters namely, nozzle temperature, extrusion speed and fill density. Mathematical models were developed and tested for accuracy and extrusion time using Design Expert 11 software for RSM application.
Engineering Optimization
Sh. Ghasemi; A. Aghsami; M. Rabbani
Abstract
Data Envelopment Analysis (DEA) is one of the non-parametric methods for evaluating each unit's efficiency. Limited resources in the healthcare system are the main reason for measuring the efficiency of hospitals. Because Operating Rooms (OR) are the most vital part of any hospital, we determine the ...
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Data Envelopment Analysis (DEA) is one of the non-parametric methods for evaluating each unit's efficiency. Limited resources in the healthcare system are the main reason for measuring the efficiency of hospitals. Because Operating Rooms (OR) are the most vital part of any hospital, we determine the factors affecting operating rooms' efficiency and evaluate the performance and ranking of operating rooms in 10 of Tehran's largest hospitals. This model's inputs include accuracy in scheduling surgeries, average turnover time, number of successful surgeries and live patients, number of canceled surgeries, number of surgical errors, and number of emergency surgery. Also, outputs consist of the number of operating rooms and equipment, the average number of beds, the number of employees, and the patient satisfaction rate. First, we determine the weight of inputs and outputs by Group Analytic Hierarchy Process (GAHP) with considering experts' ideas in 10 hospitals; then, we utilize three types of DEA model which are input-oriented CCR (CCR-I), output-oriented CCR (CCR-O), input-output oriented CCR (CCR_IO) and AP models to estimate the efficiency of ORs and rank them.
Engineering Optimization
Sh. T. Alam
Abstract
The development of a product demands numbers of consideration and customer-based product dominates the present market. This study aims to formulate a customer-oriented product and investigate the optimum design parameters level for this formulation. The customer-oriented product named 'CNC PCB Plotter' ...
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The development of a product demands numbers of consideration and customer-based product dominates the present market. This study aims to formulate a customer-oriented product and investigate the optimum design parameters level for this formulation. The customer-oriented product named 'CNC PCB Plotter' – is proposed as a handy tool to make a single PCB within a short time and cost. In the sophisticated art of product design, the desires of the customer should be the only constraint. With this in mind, an organized approach is conducted to formulate the product. Suitable design parameters with their optimum ranges provide the sustainability of the product. Response Surface Methodology (RSM) is applied to determine the optimum level of design parameters. A 2-level 3 factorial Central Composite Design (CCD) provides the experimental trails. This research involves the customer demand and specifies the design parameter, such as cutting speed, feed rate, and depth of cut. The average dimensional accuracy is taken as a response and found 0.027 µm with a combination of cutting speed 53.676 m/min, feed rate 253.272 mm/min, and depth of cut 0.49.mm, which is found to be the optimum value.
Engineering Optimization
M. Sayadi; M. Ghomi
Abstract
During the past years, extensive studies have been performed on concretes containing rice husk ash and recycled aggregates, which have shown the advantages of those concretes. Comparison of recycled concrete materials from the aggregates of quarrying plants for use in laboratory mixtures is the difference ...
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During the past years, extensive studies have been performed on concretes containing rice husk ash and recycled aggregates, which have shown the advantages of those concretes. Comparison of recycled concrete materials from the aggregates of quarrying plants for use in laboratory mixtures is the difference between this study and previous studies in this field. In addition to mechanical tests and evaluation of the performance of recycled concrete and comparison of ordinary concrete, the evaluation of the design economy and environmental protection are also examined. The main purpose of this study is to achieve and introduce the most optimal conditions for the use and application of recycled stone materials in concrete production. Evaluate and compare the effectiveness of each of the hardened concrete parameters such as mechanical properties and engineering properties (compressive and tensile strength) as a result of using recycled aggregate replacement values, as well as conserving environmental resources that are non-renewable in many industries. Or renewed over very long periods of time, reducing construction waste and environmental pollution, creating employment and economic benefits are other goals pursued in this study.
Engineering Optimization
B. Ejlali; S. F. Bagheri; Kh. Ghaziyani
Abstract
Disaster relief logistics is considered to be one of the major activities in disaster management. This research studies response phase of the disaster management cycle. To do so, a multi-purpose integrated model for a three-level relief cycle logistics is provided under an uncertainty condition and on ...
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Disaster relief logistics is considered to be one of the major activities in disaster management. This research studies response phase of the disaster management cycle. To do so, a multi-purpose integrated model for a three-level relief cycle logistics is provided under an uncertainty condition and on a periodic basis. In this model, inventory transfer, vehicle routing, distribution and sending relief goods are modeled on a periodic basis. In addition, in order to solve the proposed mathematical model, ultra-initiative particles swarm algorithm in combination with variable neighborhood search based on Pareto archive is proposed. To prove the efficiency of the proposed particles swarm algorithm, several sample problems are randomly selected considering the solved problems in the literature and are solved by particles swarm algorithm. These problems are also solved by genetic algorithm and the results obtained from these two algorithms are compared in terms of quality, dispersion and integrity indices. The results show that compared to genetic algorithm, particles swarm algorithm is more capable of producing more integrated, qualified and dispersed responses. Moreover, the results show that the solution time of genetic algorithm is less than that of the proposed algorithm.
Engineering Optimization
S. Aluvihara; J. K. Premachandra
Abstract
Crude oil is a predominant natural resource and also it causes the metallic corrosion in the industry of crude oil refining due to some corrosive properties of crude oils. In the current research, it is expected to investigate the effect of such compounds of crude oils on the rate of corrosion of seven ...
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Crude oil is a predominant natural resource and also it causes the metallic corrosion in the industry of crude oil refining due to some corrosive properties of crude oils. In the current research, it is expected to investigate the effect of such compounds of crude oils on the rate of corrosion of seven different types of ferrous metals which are frequently used in the crude oil refining industries. The sulfur content, salt content, acidity, and mercaptans content of each crude oil are determined in order to use XRF analyzer, salt analyzer, and titration methods. A set of equal size metal pieces are immersed in both crude oils separately for 15, 30, and 45 days and their corrosion rates are determined by using relative weight loss after these time periods while observing the corroded metal surface under the optical microscope, and the dissolved metal concentration in each crude oil sample is tested by the AAS. The hardness of each metal piece is tested before and after the immersion in crude oil with the aid of Vicker’s hardness tester. It is found that a higher amount of sulfur, acidity, and mercaptans and lower amount of salt present in Das blend than Murban. We have found there is some significant rate of corrosion from most of the metals and higher amount of dissolved metallic concentration in samples of both crude oils with respect to those metals. It is observed that there is a slight reduction in hardness of all metal pieces due to the corrosion.
Engineering Optimization
K. Chitra; P. Halder
Abstract
In today’s competitive environment completing a project within time and budget, is very challenging task for the project managers. This aim of this study is to develop a model that finds a proper trade-off between time and cost to expedite the execution process. Critical path method (CPM) is used ...
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In today’s competitive environment completing a project within time and budget, is very challenging task for the project managers. This aim of this study is to develop a model that finds a proper trade-off between time and cost to expedite the execution process. Critical path method (CPM) is used to determine the longest duration and cost required for completing the project and then the time-cost trade–off problem (TCTP) is formulated as a linear programming model. Here, LINDO program is used to determine the solution of the model. To implement the proposed model, necessary data were collected through interviews and direct discussion with the project managers of Chowdhury Construction Company, Dhaka, Bangladesh. The analysis reveals that through proper scheduling of all activities, the project can be completed within 120 days from estimated duration of 140 days. Reduction of project duration by 17% is achieved by increasing cost by 3.73%, which is satisfactory.
Engineering Optimization
A. H. Niknamfar; H. Esmaeili
Abstract
Nanotechnology deals with studies of phenomena and manipulation on elements of matter at the atomic, molecular and macromolecular level (rangefrom1to100nm), where the properties of matter are significantly different from properties at larger scales of dimensions. Nanotechnology is science, engineering, ...
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Nanotechnology deals with studies of phenomena and manipulation on elements of matter at the atomic, molecular and macromolecular level (rangefrom1to100nm), where the properties of matter are significantly different from properties at larger scales of dimensions. Nanotechnology is science, engineering, and technology conducted at the nanoscale, which is about 1 to 100 nm where nano denotes the scale range of 10-9 and nanotechnology refers the properties of atoms and molecules measuring thoroughly 0.1 to 1000 nm. Nanotechnology is highly interdisciplinary as a field, and it requires knowledge drawn from a variety of scientific and engineering arenas. There are two main types of approaches to nanotechnology: the first approach is Top-down and another one is Bottom-up approach. The Top-down approach involves taking layer structures that are either reduced down size until they reach the nano-scale or deacon structured into their composite parts. This paper aims to deal with Top-down approach in order to utilize Biopolymer nanoparticles for Creating Antimicrobial for chicken feed so that the live average time of chicken will be increased noticeably by using max-min optimization approach. Finally, the applicability of the proposed approach and the solution methodologies are demonstrated in three steps.
Engineering Optimization
C. L. Karmaker
Abstract
Exponential smoothing is a sophisticated forecasting method that works based on previous forecast plus a percentage of the forecast error. A key issue of this technique is the proper choice of exponential smoothing constant. In order to minimize forecasting errors, choosing an appropriate value of smoothing ...
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Exponential smoothing is a sophisticated forecasting method that works based on previous forecast plus a percentage of the forecast error. A key issue of this technique is the proper choice of exponential smoothing constant. In order to minimize forecasting errors, choosing an appropriate value of smoothing constant is very crucial. In this study, a framework is developed for the selection of optimal value of smoothing constant that minimizes a measure of forecast errors like mean square error (MSE) and mean absolute deviation (MAD). Both “trial & error” and Excel based non-linear optimizer (“Excel Solver”) are used for this purpose. To validate the proposed model, necessary demand data of Ruchi Jhal Muri from years 2010-2016 from Square Food & Beverage Ltd. in Mohakhali, Dhaka were collected. The optimum values of smoothing constant under trial & error method are 0.31 and 0.14 for minimum MAD and MSE respectively whereas for excel solver, values are 0.314 and 0.143 with respect to minimum MAD and MSE. Although both methods provide approximately the same results but excel solver is much easier & requires less time for deriving optimum solution. This study will provide an outline for the forecast planners as well as manufacturers to improve the accuracy of exponential forecasting through using Excel Solver for determining the optimum value of smoothing constant.
