• Advances in concrete construction
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• v.13 no.6
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• pp.433-450
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• 2022

The conventional disposal methods of waste tires are harmful to the environment. Moreover, the recycling/reuse of waste tires in domestic and industrial applications is limited due to parent product's quality control and environmental concerns. Additionally, the recycling industry often prefers powdered rubber particles (<0.60 mm). However, the processing of waste tires yields both powdered and coarser (>0.60 mm) size fractions. Reprocessing of coarser rubber requires higher energy increasing the product cost. Therefore, the waste tire rubber (WTR) less favored by the recycling industry is encouraged for use in construction products as one of the environment-friendly disposal methods. In this study, WTR fiber >0.60 mm size fraction is collected from the industry and sorted into 0.60-1.18, 1.18-2.36-, and 2.36-4.75-mm sizes. The effects of different fiber size fractions are studied by incorporating it as fine aggregates at 10%, 20%, and 30% in the self-compacting rubberized concrete (SCRC). The experimental investigations are carried out by performing fresh and hardened state tests. As the fresh state tests, the slump-flow, T500, V-funnel, and L-box are performed. As the hardened state tests, the scanning electron microscope, compressive strength, flexural strength and split tensile strength tests are conducted. Also, the water absorption, porosity, and ultrasonic pulse velocity tests are performed to measure durability. Furthermore, SCRC's energy absorption capacity is evaluated using the falling weight impact test. The statistical significance of content and size fraction of WTR fiber on SCRC is evaluated using the analysis of variance (ANOVA). As the general conclusion, implementation of various size fraction WTR fiber as fine aggregate showed potential for producing concrete for construction applications. Thus, use of WTR fiber in concrete is suggested for safe, and feasible waste tire disposal.

• Industrial Engineering and Management Systems
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• v.12 no.4
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• pp.317-329
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• 2013

In recent years, for the purpose of solving the problem regarding environment protection and resource saving, certain measures and policies have been promoted to establish a green supply chains (GSC) with material flows from collection of used products to reuse of recycled parts in production of products. In this study, we propose an optimal operation of the GSC while considering the collection incentive of the used products and quality for recycling of used products. Two types of decision-making approaches are used for product quantity, collection incentive of used products and lower limit of quality level of reusable parts in the used products for recycling in the GSC. One is the decision-making under an independent policy in decentralized supply chains where a retailer and a manufacturer make decisions so as to maximize profits individually. The other is the decision-making under a cooperative policy in centralized supply chains where a retailer and a manufacturer make decisions cooperatively so as to maximize the whole system's profit. Additionally, we also discuss supply chain coordination as a manufacturer-retailer partnership based on profit sharing. Furthermore, we show the effect of the quality of the reusable parts on the optimal decisions. The collection incentive of the used products was found to bring more profitability to the GSC activity.

• Environmental Engineering Research
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• v.23 no.1
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• pp.92-98
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• 2018

Suitability of aluminium-based water treatment sludge (WTS), a waste product from water treatment facilities, was assessed for removal of heavy metals from an electroplating wastewater which had high concentrations of copper and chromium along with other heavy metals. Batch tests with simulated wastewater in single- and multi-metal solutions indicated the influence of initial pH and WTS dose on removal of six metals namely Cu(II), Co(II), Cr(VI), Hg(II), Pb(II) and Zn(II). In general, removal of cationic metals such as Pb(II), Cu(II) and Zn(II) increased with increase in pH while that of anionic Cr(VI) showed a reduction with increased pH values. Tests with multi-metal solution showed that the influence of competition was more pronounced at lower WTS dosages. Column test with diluted (100 times) real electroplating wastewater showed complete removal of copper up to 100 bed volumes while chromium removal ranged between 78-92%. Other metals which were present in lower concentrations were also effectively removed. Mass balance for copper and chromium showed that the WTS media had Cu(II) and Cr(VI) sorption capacities of about 1.7 and 3.5 mg/g of dried sludge, respectively. The study thus indicates that WTS has the potential to be used as a filtration/adsorption medium for removal of metals from metal-bearing wastewaters.

• BMB Reports
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• v.45 no.8
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• pp.427-432
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• 2012

Primary cilia, single hair-like appendage on the surface of the most mammalian cells, were once considered to be vestigial cellular organelles for a past century because of their tiny structure and unknown function. Although they lack ancestral motility function of cilia or flagella, they share common ground with multiciliated motile cilia and flagella on internal structure such as microtubule based nine outer doublets nucleated from the base of mother centrioles called basal body. Making cilia, ciliogenesis, in cells depends on the cell cycle stage due to reuse of centrioles for cell division forming mitotic spindle pole (M phase) and assembling cilia from basal body (starting G1 phase and maintaining most of interphase). Ciliary assembly required two conflicting processes such as assembly and disassembly and balance between these two processes determines the length of cilia. Both process required highly conserved transport system to supply needed substance to grow tip of cilia and bring ciliary turnover product back to the base of cilia using motor protein, kinesin and dynein, and transport protein complex, IFT particles. Disruption of ciliary structure or function causes multiple human disorder called ciliopathies affecting disease of diverse ciliated tissues ranging from eye, kidney, respiratory tract and brain. Recent explosion of research on the primary cilia and their involvement on animal development and disease attracts scientific interest on how extensively the function of cilia related to specific cell physiology and signaling pathway. In this review, I introduce general features of primary cilia and recent progress in understanding of the ciliary length control and signaling pathways transduced through primary cilia in vertebrates.

• Journal of the Korean Operations Research and Management Science Society
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• v.28 no.3
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• pp.135-148
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• 2003

In this paper we introduce the Internet-based purchase support systems using data mining and case-based reasoning (CBR). Internet Business activity that involves the end user is undergoing a significant revolution. The ability to track users browsing behavior has brought the vendor and end customer's closer than ever before. It is now possible for a vendor to personalize his product message for individual customers at massive scale. Most of former researchers, in this research arena, used data mining techniques to pursue the customer's future behavior and to improve the frequency of repurchase. The area of data mining can be defined as efficiently discovering association rules from large collections of data. However, the basic association rule-based data mining technique was not flexible. If there were no inference rules to track the customer's future behavior, association rule-based data mining systems may not present more information. To resolve this problem, we combined association rule-based data mining with CBR mechanism. CBR is used in reasoning for customer's preference searching and training through the cases. Data mining and CBR-based hybrid purchase support mechanism can reflect both association rule-based logical inference and case-based information reuse. A Web-log data gathered in the real-world Internet shopping mall is given to illustrate the quality of the proposed systems.

• Journal of Microbiology and Biotechnology
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• v.28 no.9
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• pp.1493-1501
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• 2018

Wastewater from cider factories (losses during transfers, products discarded due to quality policies, and products returned from the market) exhibits a Chemical Oxygen Demand greater than $170,000mg\;O_2/l$, mainly due to the ethanol content and carbohydrates that are added to obtain the finished product. These effluents can represent up to 10% of the volume of cider produced, and they must be treated to meet environmental regulations. In this work, a process was developed, based on alcoholic fermentation of the available carbohydrates present in ciders. The impact of inhibitors at different pH, size and reuse of inoculums and different nutrient supplementation on the ethanol yield were evaluated. The use of a 0.5 g/l yeast inoculum and corn steep water as the nutrient source allowed for depletion of the sugars in less than 48 h, which increased the content of ethanol to more than 70 g/l.

• International Commerce and Information Review
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• v.8 no.3
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• pp.71-95
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• 2006

In recent, T-commerce is widely dispersed as alternative type of commerce. It is forecasted that t-commerce system is used more than e-commerce system. Therefore more and more t-commerce-related industries are also recognizing that t-commerce is a critical business model. It is needed to understand the concept of t-commerce and develop the t-commerce marketing strategy. CEO analyses consumer's behaviors according to the data about buyers and applies the advantage of t-commerce to the communication with customers. This t-commerce system plays an important role in maximizing customer satisfaction and affecting their intention to reuse it. Therefore this paper attempts to identify T-commerce critical success factors and divide between use-intention group and unuse-intention group by taking out a discriminant function by the discriminant analysis. This lays a foundation in developing T-commerce strategy. According to the discriminant function extracted, convenience factor, amusement factor, system quality factor, product perception factor are significant in the sequence of influential degree. However, usefulness factor and speedy connection factor are not significant. In result, the target hitting rate is 77.9% in the first unuse-intention group and it is 95.2% in the second use-intention group. The total discriminant target hitting rate is computed to higher value, 86.55%. The statistic package, SPSS 12.0, is used to survey and analyse data and test the hypothesis. The validity and reliability of variables are verified by both reliability analysis and factor analysis. The discriminant analysis is used to tell the difference between use-intention group and unuse-intention group.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.423-424
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• 2009

The use of fly-ash has been being increased to prevent alkali-aggregate reaction in concrete and to reuse industrial by-product. However the absorption of unburnt carbon to cement particles due to the increase of fly-ash usage decreases air content result in the risk at durability due to free-thawing. The properties of entrained air in fresh concrete, with various fly-ash replacement ratios and different types of air entraining agents, have been analyzed to suggest basic data for the stable air entraining property with large amount of fly-ash replacement in concrete.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.3
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• pp.112-123
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• 2015

There are many systems for cutting plates or pipes into a desired shape. A typical system is a plasma cutter. It uses plasma, which means that an effective design of the table supporting the workpiece is an important issue in order to ensure a long operational career. Conventional roller-support worktables have a short lifespan due to scratches from the plasma, and it is also difficult to maintain the roller balance. By using a bolt-fastening method, deformation and failure of the final product can occur due to the stress concentration at bolting points. To escape these issues, a polygon support and bracket fastening method was designed. Due to polygons having a number of support surfaces, when one surface has been damaged, it is possible to reuse the support by utilizing a different surface. The bracket-fastening method can extend the worktable lifetime and increase productivity by reducing stress concentration. In this paper, the polygon support/bracket-fastening method is compared with existing technologies. Consequently, performance benchmarks are verified through a structure analysis and experimentation.

• International Journal of CAD/CAM
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• v.3 no.1_2
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• pp.19-29
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• 2003

Disassembly is a fundamental process needed for component reuse and material recycling in all assembled products. Integral attachments, also known as 'snap' fits, are favored fastening means in design for assembly (DFA) methodologies, but not necessarily a favored choice for design for disassembly. In this paper, design methods of a new class of integral attachments are proposed, where the snapped joints can be disengaged by the application of localized heat sources. The design problem of reversible integral attachments is posed as the design of compliant mechanisms actuated with localized thermal expansion of materials. Topology optimization technique is utilized to obtain conceptual layout of snap-fit mechanisms that realizes a desired deformation of snapped features for joint release. Two design approaches are attempted and design results of each approach are presented, where the geometrical configuration extracted from optimal topologies are simplified to enhance the manufacturability for the conventional injection molding technologies. To maximize the magnitude of deformation, a design scheme has been proposed to include boundary conditions as design variables. Final designs are verified using commercial software for finite element analysis.