• Journal of the Korean Wood Science and Technology
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• v.47 no.3
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• pp.277-289
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• 2019

Herein, a case study discussing the effect of carbonaceous aerosol pollution, which is emitted during the charcoal kiln manufacturing processes or carbonization processes, on the atmospheric environment is presented . In South Korea, in situ analysis of different charcoal production plants specialized in the production of charcoal sauna indicate that the emitted organic carbon (OC) and elemental carbon (EC) aerosols are significantly influenced by the nature of the biomass and technological processes, i.e., treatment or emissions abatement systems for the exhaust effluent gases. In detail, total carbon (TC), which is calculated as the sum of OC and EC emission factors, varied widely from a charcoal production site to another ranging from 21.8 to 35.8 gTC/kg-oak, where the mean value for the considered production sites was approximately 28 gTC/kg-oak (N = 7 and sum = 196.4). Results indicate that the emission factors from a modern charcoal production process in South Korea are quantitatively lower in comparison with the traditional kiln. This study aims to propose advanced wood processes for the production of charcoal from the viewpoint of environmental protection policy and green engineering.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.4
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• pp.23-32
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• 2020

Many small and medium-sized manufacturing companies process various product types to respond different customer orders in a single production line. To improve their productivity, they often apply batch processing while considering various product types, constraints on batch sizes and setups, and due date of each order. This study introduces a batch scheduling heuristic for a production line with multiple product types and different due dates of each order. As the process times vary due to the different batch sizes and product types, a recursive equation is developed based on a flow line model to obtain the upper bound on the completion times with less computational complexity than full computation. The batch scheduling algorithm combines and schedules the orders with same product types into a batch to improve productivity, but within the constraints to match the due dates of the orders. The algorithm incorporates simple and intuitive principles for the purpose of being applied to small and medium companies. To test the algorithm, two case studies are introduced; a high pressure coolant (HPC) manufacturing line and a press process at a plate-type heat exchanger manufacturer. From the case studies, the developed algorithm provides significant improvements in setup frequency and thus convenience of workers and productivity, without violating due dates of each order.

• Applied Chemistry for Engineering
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• v.29 no.5
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• pp.613-619
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• 2018

In this study, various influent sludge pre-treatment methods and the internal recirculation of thickened sludge from effluents using a liquid/solid separation unit were adopted to investigate their effects on the sludge digestion and methane production in a combined mesophilic anaerobic and thermophilic aerobic sludge digestion process. A lab-scale combined sludge digestion process was operated during 5 phases using different feed sludge pre-treatment strategies. In phase 1, the feed sludge was pre-treated with a thermal-alkaline method. In contrast, in phases 2, 3 and 4, the internal recirculation of thickened sludge from the effluent and thermal-alkaline, thermal, and alkaline pre-treatment (7 days) were applied to the combined process. In phase 5, the raw sludge without any pre-treatment was used to the combined process. With the feed sludge pre-treatment and internal recirculation, the experimental results indicated that the volatile suspended solid (VSS) removal was drastically increased from phases 1 to 4. Also, the methane production rate with the thermal-alkaline pre-treatment and internal recirculation was significantly improved, showing an increment to 285 mL/L/day in phase 2. Meanwhile, the VSS removal and methane production in phase 5 were greatly decreased when the raw sludge without any pre-treatment was applied to the combined process. Considering all together, it was concluded that the combined process with the thickened sludge recirculation and thermal-alkaline pre-treatment can be successfully employed for the highly efficient sewage sludge reduction and methane gas production.

• Journal of Information Technology Services
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• v.15 no.1
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• pp.299-319
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• 2016

This study first introduces platform services and their business models. On the basis of the concepts of business ecosystem, we present a framework for distinguishing types of the platform service business models. Two key characteristics of business ecosystems-ecosystem configuration and value production process-are employed as fundamental dimensions for constructing typology. In particular, we also present the notion of value ecosystem, where not a single platform provider but a federation of platforms constitutes a virtual platform and completes a service system. The value ecosystem represents two distinct types of platform service business models : meta-platform ecosystem and platform coalition ecosystem. They show different governance structure in the platform federation and service flows across the ecosystem. We present detailed analyses of these two value ecosystems focusing on relevant cases of e-payment FinTech : Apple Pay as an example of meta-platform and Kakao Pay for platform coalition. Our conceptual typology contributes to platforms' proper strategy formulation and presents policy implications to, for example, platform neutrality.

• Proceedings of the Safety Management and Science Conference
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• 2004.05a
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• pp.61-65
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• 2004

As technique that can contribute in quality improvement in design process to overcome shortcoming of traditional quality control, call design or development department quality control activity that is achieved to reduce gun damage shuddering at circle minimizing change or side effect of product performance as off-line quality control. This paper discuss optimal process design of investment projects expansion and replacement investment on each line or individual in the production. Generally optimal plant design has add to a few method by Subsidiary means with use a especial method. And then in this paper, a Robust design is presented, which may be effective to the processes appraisal or improvement. We propose that should make a optimal plant design model for reducing field failure rate to assign by real data on different factors in plant system. Using this model, robust design of taguchi method used in this comprehensive method for reducing field failure rate in plant system.

• Proceedings of the KWS Conference
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• 2007.11a
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• pp.42-44
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• 2007

Methods of repair welding are different to production welding for welding position, welding process, welding power source, heating methods. This study investigated proper the welding process used the welding process SMAW and GTAW in the weldment of inconel filler metals. Mechanical test showed that SMAW and GTAW process had higher mechanical properties than those of material specification. Both SMAW and GTAW welding process can appy the repair welding. In comparison, GTAW welding process had more higher mechanical properties in the weldment.

• Journal of computational fluids engineering
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• v.16 no.1
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• pp.42-47
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• 2011

In this paper, various operating parameters of stream reforming process from methane in stream reformer and preconverter for MCFC is studied by numerical method. Commercial code is used to simulated the porous catalyst with user subroutine to model three dominant chemical reactions which are Stream Reforming(SR), Water-Gas Shift(WGS), and Direct Stram Reforming(DSR). The hydrogen production is tested with different wall temperature and different reactor shapes. The calculated results of the concentration of hydrogen in stream reformer are very well consistent with experimental results. This numerical study gives the design reactor wall temperature condition and size of reactor to satisfy the required fuel conversion.

• Proceedings of the KWS Conference
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• 2010.05a
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• pp.26-26
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• 2010

EGW process has been applied to joining of ship block with vertical-up position at high production rate. The workability of EGW, however, has been interrupted by too much slag production. Two electrodes EGW showed more severe workability than that of one electrode EGW. Therefore, to understand the effect of discharge amount of EGW slag on workability and mechanical properties, two different slag discharge amount have been controlled at the same welding conditions. The results are as follows; 1) Workability has been improved by any additional slag discharge. 2) Mechanical properties have been deteriorated with any additional slag discharge. 3) Chemical compositions of weld metal have been changed by any additional slag discharge.

• Journal of Industrial Technology
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• v.35
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• pp.59-65
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• 2015

As the fossil fuels are depleted nowadays, development of alternative energies is absolutely required in the world. Efficient production of hydrogen by water-splitting using solar energy can be one of the methods to solve the global energy and environmental problems. But this method has a problem of low conversion efficiency. The application of graphene can be one method to help increase the conversion efficiency. For this reason, mass production of high quality graphene is required. In this study, we prepared graphene using the chemical exfoliation method. We applied the Hummer's method and Tour's method to oxidize the graphite and could get the different Graphene Oxide(GO) from different process conditions. We also tried to convert the GO to graphene by thermal reduction and could remove functional group of GO effectively. The control of oxidation conditions was quite important to obtain the high quality graphene.

• Wind and Structures
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• v.17 no.6
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• pp.671-680
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• 2013

Static aeroelastic is investigated in a wind turbine blade. Imposed to different loadings, the very long and flexible structures of blades experience some changes in its preliminary geometry. This results in variations of aerodynamic loadings. An iterative approach is developed to study the interactions between structure and aerodynamics evaluating variations in induced stresses in presence of aeroelasticity phenomenon for a specific wind turbine blade. A 3D finite element model of the blade is constructed. Aerodynamic loading is applied to the model and deflected shape is extracted. Then, aerodynamic loadings are updated in accordance with the new geometry of the deflected blade. This process is repeated till the convergence is met. Different operational conditions consisting of stand-by, start-up, power production and normal shut-down events are investigated. It is revealed that stress components vary significantly in the event of power production at the rated wind speed; while it is less pronounced for the events of normal shut-down and stand-by.