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Natural jute laminate for the improvement of strength properties of concrete specimen

Zulfikar Achmad Jusuf, Yaakob Mohd Yuhazri, Umarfaruq Hel Mee, Syah Rahmad

Engineering Transactions

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2023

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Vol. 71, iss. 4

507--518

EN

In the last decade, the exploration and investigation of natural ingredients as alternative materials for metal substitutes have been continuously conducted to produce eco-friendly products with sufficiently good strength. The climate and geography of countries like Indonesia provide that such materials are available abundantly and can be easily replanted. Thus, these materials have considerable potential for application in various products. The purpose of this study is to analyze the compressive and tensile strength of a cylindrical column concrete structure reinforced externally with laminate composite materials derived from jute fabric sheets. The specimen manufacturing method uses a vacuum bagging technique with the specimen size specified in the ASTM C39 test standard. After manufacturing, the specimens underwent the treatment of immersion in clean water for 28 days, followed by drying at room temperature for additional 28 days. The column concrete specimens were wrapped with laminate composite materials with variations in several layers of jute fabric. Compressive strength and splitting tensile tests were conducted according to ASTM C39 and ASTM C496 test standards, respectively. The test results showed that applying laminate composite sheaths on the outer surface of the column concrete structure resulted in an increase in strength of up to 100% for both compressive strength and splitting tensile strength. The magnitude of such an increase in strength is reported in this article.

2

Optimizing the Multi-Level Location-Assignment Problem in Queue Networks Using a Multi-Objective Optimization Approach

Syah Rahmad, Elveny Marischa, Soerjati Enni, Guerrero John William Grimaldo, Jowad Rawya Read, Suksatan Wanich, Aravindhan Surendar, Voronkova Olga Yuryevna, Mavaluru Dinesh

Foundations of Computing and Decision Sciences

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2022

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Vol. 47, No. 2

177--192

EN

Using hubs in distribution networks is an efficient approach. In this paper, a model for the location-allocation problem is designed within the framework of the queuing network in which services have several levels, and customers must go through these levels to complete the service. The purpose of the model is to locate an appropriate number of facilities among potential locations and allocate customers. The model is presented as a multi-objective nonlinear mixed-integer programming model. The objective functions include the summation of the customer and the waiting time in the system and the waiting time in the system and minimizing the maximum possibility of unemployment in the facility. To solve the model, the technique of accurate solution of the epsilon constraint method is used for multi-objective optimization, and Pareto solutions of the problem will be calculated. Moreover, the sensitivity analysis of the problem is performed, and the results demonstrate sensitivity to customer demand rate. Based on the results obtained, it can be concluded that the proposed model is able to greatly summate the customer and the waiting time in the system and reduce the maximum probability of unemployment at several levels of all facilities. The model can also be further developed by choosing vehicles for each customer.

3

Designing a Green Supply Chain Transportation System for an Automotive Company Based On Bi-Objective Optimization

Syah Rahmad, Nasution Mahyuddin M., Shol Vladimir Vladimirovich, Kireeva Natalia, Jalil Abduladheem Turki, Chen Tzu-Chia, Aravindhan Surendar, Abood Emad Salaam, Alkaim Ayad F.

Foundations of Computing and Decision Sciences

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2022

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Vol. 47, No. 2

193--207

EN

Recently, due to the increasing awareness of communities regarding environmental issues and environmental regulations, companies have evolved to provide products with lower prices and better quality to retain and attract customers. Economics should also pay attention to environmental goals. Therefore, it is essential to provide a supply chain model that can consider both economic and environmental objectives. In this paper, the green direct supply chain network is presented to an automotive company, including five suppliers, primary warehouses, manufacturing plants, distributors, and sales centers. The objectives of this model are to minimize the total cost of construction, transportation, and the amount of carbon dioxide emissions during forwarding network transportation at all levels. The proposed model is also drawn using the weight method, which is one of the methods for solving multi-objective problems, and the solution of the model part. Ultimately, it has been discussed how much the automobile company should focus on reducing carbon dioxide so that managers can determine the best solutions from the Pareto border according to their organization's priorities, which can be environmental or financial.

4

Design a Multi Period Closed-Loop Supply Chain Program to Supply Recycled Products

Syah Rahmad, Chetthamrongchai Paitoon, Thuc Dao Chanh, Yuminarti Umi, Murtini Sri, Iswanto A. Heri, Vasilieva Nadezhda Konstantinovna, Kireeva Natalia, Aravindhan Surendar

Foundations of Computing and Decision Sciences

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2022

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Vol. 47, No. 2

163--176

EN

Over the course of the last decades, closed-loop supply chains (CLSC) and reverse logistics issues have attracted increasing attention owing to strict environmental laws, social responsibilities, economic interests, and customer awareness. Hence, the issue of closed-loop supply chain and reverse logistics has emerged as a field of research in the new era. This issue has received much attention because it allows recyclable products to return to their original cycle. Therefore, this study primarily intends to present a mathematical model for designing a supply chain network for recycled products. The multi-stage and multi-period objective function of the closed-loop supply chain is presented to meet that aim. In this chain, dismantling, recycling, and disposal centers are considered. The objective function is to reduce the total cost of the closed-loop supply chain. The results of optimizing the mathematical model demonstrate that this model has the necessary efficiency for use in recycled products.