• Korean Journal of Environmental Agriculture
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• v.32 no.2
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• pp.108-116
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• 2013

BACKGROUND: Certain crop-based waste materials have been recognized as cost-effective and highly efficient adsorbents for removal and recovery of different kind of heavy metals from aqueous solutions. The ability is strongly attributed to the carboxyl functional group of some pectin substances such as galacturonic acid often found in fruit peels. The present manuscript was aimed at assessing the potential applicability of banana peel for metal removal from contaminated waters. METHODS AND RESULTS: As revealed by laboratory investigations, banana peel contains pectin (10-21%), lignin (6-12%), cellulose (7.6-9.6%), and hemicelluloses (6.4-9.4%). The pectin extraction is reported to have glucose, galactose, arabinose, rhamnose, xylose, and galactouroninc acid. Several studies conducted under different conditions proved that banana peel is capable of adsorbing 5.71, 2.55, 28.00, 6.88, 7.97, and 5.80 mg/g of $Cd^{2+}$, $Co^{2+}$, $Cu^{2+}$, $Ni^{2+}$, $Pb^{2+}$, and $Zn^{2+}$, respectively, from aqueous solutions. Adsorption capacity is, however, dependent upon several factors including solution pH, dose of adsorbent and metal concentration, contact time and shaking speed. CONCLUSION(S): Since the annual world production of banana exceeds 100 million tons, about 40 million tons of banana peel (40% of total weight of the fresh fruit) remains vastly unused. Exploring a sound technology with banana peel would therefore, not only address the much needed sustainable tool for cleaning contaminated waters, but of course bring an additional value to the banana industry worldwide.

• Earthquakes and Structures
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• v.2 no.3
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• pp.233-256
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• 2011

This paper investigates the applicability of newly developed Cu-Al-Mn shape memory alloy (SMA) bars to retrofitting of historical masonry constructions by performing quasi-static tests of half-scale brick walls subjected to cyclic out-of-plane flexure. Problems associated with conventional steel reinforcing bars lie in pinching, or degradation of stiffness and strength under cyclic loading, and in their inability to restrain residual deformations in structures during and after intense earthquakes. This paper attempts to resolve the problems by applying newly developed Cu-Al-Mn SMA bars, characterized by large recovery strain, low material cost, and high machinability, as partial replacements for steel bars. Three types of brick wall specimens, unreinforced, steel reinforced, and SMA reinforced specimens are prepared. The specimens are subjected to quasi-static cyclic loading up to rotation angle enough to cause yielding of reinforcing bars. Corresponding nonlinear finite element models are developed to simulate the experimental observations. It was found from the experimental and numerical results that both the steel reinforced and SMA reinforced specimens showed substantial increment in strength and ductility as compared to the unreinforced specimen. The steel reinforced specimen showed pinching and significant residual elongation in reinforcing bars while the SMA reinforced specimen did not. Both the experimental and numerical observations demonstrate the superiority of Cu-Al-Mn SMA bars to conventional steel reinforcing bars in retrofitting historical masonry constructions.

• Membrane and Water Treatment
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• v.11 no.2
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• pp.97-109
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• 2020

Membrane fouling is the main drawback of membrane technology. Frequent membrane cleaning and membrane replacement are, therefore, required to reduce membrane fouling that causes permeate flux reduction, lower rejection, or higher operating pressure. Studies have proved that the alteration of membrane properties is the key controlling factor in lessening membrane fouling. Among stimuli-responsive membranes, thermo-responsive membrane is the most popular, with a drastic phase transition and swelling-shrinking behavior caused by the temperature change. In this study, the thermo-responsive ability of two commercial membranes, PolyCera® Titan membrane and PolyCera® Hydro membrane, at different temperatures was studied on the antifouling function of the membrane in palm oil mill effluent (POME) treatment. The evaluation of the membrane's thermo-responsive ability was done through three cycles of adsorption (fouling) and desorption (defouling) processes in a membrane filtration process. The experimental result depicted that PolyCera® Hydro membrane had a higher membrane permeability of 67.869 L/㎡.h.bar than PolyCera® Titan membrane at 46.011 L/㎡.h.bar. However, the high membrane permeability of PolyCera® Hydro membrane was compensated with low removal efficiency. PolyCera® Titan membrane with a smaller mean pore size had better rejection performance than PolyCera® Hydro membrane for all tested parameters. On the other hand, PolyCera® Titan membrane had a better hydrodynamic cleaning efficiency than PolyCera® Hydro membrane regardless of the hydrodynamic cleaning temperature. The best hydrodynamic cleaning performed by PolyCera® Titan membrane was at 35℃ with the flux recovery ratio (FRR) of 99.17 ± 1.43%. The excellent thermo-responsive properties of the PolyCera® Titan membrane could eventually reduce the frequency of membrane replacement and lessen the use of chemicals for membrane cleaning. This outstanding exploration helps to provide a solution to the chemical industry and membrane technology bottleneck, which is the membrane fouling, thus reducing the operating cost incurred by the membrane fouling.

• Journal of Microbiology and Biotechnology
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• v.23 no.5
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• pp.587-601
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• 2013

During the last few decades, it has become evident that the compatibility of the yeast biochemical environment with the ability to process and translate the RNA transcript, along with its capacity to modify a translated protein, are relevant requirements for selecting this host cell for protein expression in several pharmaceutical and clinical applications. In particular, Pichia pastoris is used as an industrial host for recombinant protein and metabolite production, showing a powerful capacity to meet required biomolecular target production levels in high-throughput assays for functional genomics and drug screening. In addition, there is a great advantage to using P. pastoris for protein secretion, even at high molecular weights, since the recovery and purification steps are simplified owing to relatively low levels of endogenous proteins in the extracellular medium. Clearly, no single microexpression system can provide all of the desired properties for human protein production. Moreover, chemical and physical bioprocess parameters, including culture medium formulation, temperature, pH, agitation, aeration rates, induction, and feeding strategies, can highly influence product yield and quality. In order to benefit from the currently available wide range of biosynthesis strategies using P. pastoris, this mini review focuses on the developments and technological fermentation achievements, providing both a comparative and an overall integration analysis. The main aim is to highlight the relevance and versatility of the P. pastoris biosystem to the design of more cost-effective microfactories to meet the increasing demands for recombinant membrane proteins and clinical antibodies for several therapeutic applications.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.5
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• pp.219-227
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• 2016

As the largest source of food waste is housing, and the food waste properties are good enough to recycle, the proactive approach to conventional food waste disposal is highly regarded. This research is to examine food waste management in the Seoul Metropolitan Area (SMA) and non-SMA and to analyze the public inclination to disseminate zero-food waste system (ZFWS) with fermentation and extinction technology in multifamily housing estates. The self-administered questionnaire survey was conducted and the collected data were statistically analyzed. The main findings are summarized as follows: food waste in multifamily housing estates were retrieved by refuse truck and largely recycled for compost and forage. Also, many local governments were in favor of ZFWS, and unwilling to invest in it due to financial constraint. It's found that logistics of ZFWS is likely to be influenced by important features such as a considerable amount of cost saving, effective energy recovery, and efficient operation/management.

• Journal of Korean Neurosurgical Society
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• v.38 no.4
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• pp.281-286
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• 2005

Objective : The authors report our experience of urokinase thrombolysis in treating patients harboring nonaneurysmal spontanesous intraventricular hemorrhage[IVH] and evaluated complications, safety and feasibility of this procedure retrospectively. Methods : Fifty-three patients with nonaneurysmal IVH>15mL without underlying structural etiology or coagulopathy were recruited. The patients with Glasgow Coma Scale[GCS]<5 were excluded. A catheter was directed into the IVH. Hematoma aspiration was followed by instillation of urokinase at the ear level of drainage bag under intracranial pressure monitoring system. This was repeated every 6hours until half of its initial volume. For analysis of prognostic factors, we classified the patients into two groups by Glasgow outcome scale[GOS]; good [$GOS\;{\ge}3$] and bad [GOS<3] prognosis group, and performed comparative analysis between two groups. Results : Mean age was 60.2years. The baseline hematoma size ranged 16 to 72mL. IVH volume reduction was done by an average of 74.2%. As complications, there were 3cases of rebleeding and 2cases of ventriculitis. No intracranial adverse effects were observed during thrombolytic theraphy. At 6months after the procedure, 29patients had achieved a good recovery, 15remained vegetative. 9patients died in hospital. The main good prognostic factors were young age, small IVH volume, and high GCS. Conclusion : The results of this study suggest that this relatively easy and safe method of treatment will improve the prognosis. However, further clinical studies also must assess optimal thrombolytic dosage, frequency, and timing of urokinase instillation for safety and effectiveness and must include controlled comparisons of mortality, disability outcome, quality of life, time until convalescence, and cost of care in treated and untreated patients.

• Journal of the Korean Society of Hazard Mitigation
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• v.4 no.1 s.12
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• pp.65-75
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• 2004

Roadbed failure due to the natural disaster may bring out social and economic damage such as the loss of life and property, the consumption of time and cost for recovery, and the delay of logistics in railway In this study, the method using geosynthetic soilbag was applied to rehabilitation of the railway roadbed which was failed by disaster. The full scale tests with the simulated train loading were performed in order to evaluate the static and dynamic performance at the railway roadbed using geosynthetic soilbag. The results of these tests were compared with unreinforced and reinforced cases with geosynthetic soilbag, respectively The data gathered by various measurement devices from these full scale tests would be useful to evaluate and understand the roadbed with geosynthetic soilbag. In conclusion, geosynthetic soilbag was evaluated as a permanent restoration method to reinforce the roadbed of railway.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.12
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• pp.2305-2309
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• 2016

Cloud Computing Service should support efficiency and stability. United States of America, for example, provides FedRAMP (Federal Risk and Authorization Management Program) accreditation to certify cloud computing service and hence growth of computing service industry is giving benefits of cost reduction and efficiency to companies. However, the use of computing service brings more risk than ever. Because cloud computing holds all the data of multiple companies, problems such as hacking bring out control loss of service and as a result total data of companies can be lost. Unfortunately, cloud computing certification programs do not have any good solutions for this data loss and companies may lose all the important data without any proper data backup. This paper studies such problems in terms of backup problem and provides Data Availability Zone solution for recovery and safe saving of data so that computing service can offer better efficiency and stability.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.37 no.6
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• pp.25-34
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• 2000

This paper describes design of a 250-Mbps 10-channel optical receiver array for parallel optical interconnection with the general-purpose CMOS technology The optical receiver is one of the most important building blocks to determine performance of the parallel optical interconnection system. The chip in CMOS technology makes it possible to implement the cost-effective system also. Each data channel consists of analog front-end including the integrated photo-detector and amplifier chain, digital block with D-FF and off-chip driver. In addition, the chip includes PLL (Phase-Lock Loop) for synchronous data recovery. The chip was fabricated in a 0.65-${\mu}{\textrm}{m}$ 2-poly, 2-metal CMOS technology. Power dissipation of each channel is 330㎽ for $\pm$2.5V supply.

• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.3
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• pp.214-222
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• 2015

The superiority of gallium nitride FET (GaN FET) over silicon MOSFET is examined in this paper. One of the outstanding features of GaN FET is low reverse-recovery charge, which enables continuous conduction mode operation of totem-pole bridgeless boost power factor correction (PFC) circuit. Among many bridgeless topologies, totem-pole bridgeless shows high efficiency and low conducted electromagnetic interference performance, with low cost and simple control scheme. The operation principle, control scheme, and circuit implementation of the proposed topology are provided. The converter is driven in two-module interleaved topology to operate at a power level of 5.5 kW, whereas phase-shedding control is adopted for light load efficiency improvement. Negative bias circuit is used in gate drivers to avoid the shoot-through induced by high speed switching. The superiority of GaN FET is verified by constructing a 5.5 kW prototype of two-module interleaved totem-pole bridgeless boost PFC converter. The experiment results show the highest efficiency of 98.7% at 1.6 kW load and an efficiency of 97.7% at the rated load.