• Applied Chemistry for Engineering
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• v.27 no.5
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• pp.532-536
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• 2016

In this study, single-stage continuous anaerobic reactors to treat sewage sludge were operated under different temperature (55 and $35^{\circ}C$; $R_{TAD}$ and $R_{MAD}$) to evaluate the reactor stability and performance of the thermophilic and mesophilic anaerobic digestion. During the overall digestion, both anaerobic reactors maintained quite stable and constant pH and total alkalinity (TA) values in the range of 6.5-8.0 and 3-4 g $CaCO_3/L$, respectively. After the start-up period, $R_{TAD}$ showed 10% higher VS removal efficiency than that of $R_{MAD}$ ($R_{TAD}$; 43.3%; $R_{MAD}$ : 33.6%). Although organic acids such as acetic and propionic acid were detected in both anaerobic reactors at the start-up period, all organic acids in $R_{TAD}$ and $R_{MAD}$ were consumed at the steady state condition. Also $R_{TAD}$ showed 31.4 % higher methane production rate (MPR) than that of $R_{MAD}$ at the steady state condition ($R_{TAD}$; 243 mL $CH_4/L/d$; $R_{MAD}$ : 185 mL $CH_4/L/d$). Meanwhile, the experimental results indicated similar methane yield between $R_{TAD}$ and $R_{MAD}$.

• Environmental Engineering Research
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• v.24 no.1
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• pp.38-44
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• 2019

The Biochemical Methane Potential (BMP) of fresh leachate and domestic wastewaters codigestion was determined by laboratory Bach Tests at $35^{\circ}C$ over a period of 90 d using a wide range of leachates volumetric ratios from 0% to 100%. To simulate wastewaters plant treatment step, all the ratios were first air stripped for 48 h before anaerobic incubation. The kinetic of biogas production was assessed using modified Gompertz model and exponential equation. The results obtained showed that cumulative biogas production was insignificant in the case of wastewaters monodigestion while the codigestion significantly improves the BMP. Air stripping pretreatment had positive effect on both ammonium concentration and volatiles fatty acids with reduction up to 75% and 42%, respectively. According to the Modified Gompertz model, the optimal anaerobic co-digestion conditions both in terms of maximal biogas potential, start-up period and maximum daily biogas production rate, could be achieved within large leachate volumetric ratios from 25% to 75% with a maximum BMP value of 438.42 mL/g volatile solid at 50% leachate ratio. The positive effect of codigestion was attributed to a dilution effect of chemical oxygen demand and volatile fatty acid concentrations to optimal range that was between 11.7 to $32.3gO_2/L$ and 2.1 to 7.4 g/L, respectively. These results suggested that the treatment of fresh leachate by their dilution and co digestion at wastewaters treatment plants could be a promising alternative for both energetic and treatment purposes.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.15 no.2
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• pp.193-208
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• 2020

In this study, we investigate the effects of technology innovation investments and employment on credit ratings of very small start-up businesses using the data period of 2009 till 2015 test two hypotheses: asymmetric information hypothesis or competence hypothesis. We use financial and non-financial data of 51,903 observations of 12,028 small businesses from a database of a commercial bank and fixed effects panel models and two-stage instrumental variable models. We find that in the short-run small size startups show lower credit ratings than non-startups, and that both technology innovation activities and employment capability improve their credit ratings. In the long-run, technology innovation investments do not improve their credit ratings of later years while employment capability improve their credit ratings of the subsequent year. In addition, the age of startups improves their credit ratings of the current year and until the subsequent two years while employee productivity, fixed ratio and ROA positively affect their credit ratings for up to three years. However, short-term and overall debt ratios, cost of borrowings and firm-size negatively affect their credit ratings for up to three years. The results of the study on credit ratings suggest that credit rating agencies seem to consider both technology innovation activities and employment capability in the credit ratings of small start-ups as 'competence factors' rather than 'asymmetric information factors' with inefficiency and cost burdens. The results also suggest that we must find ways to reflect properly the severe asymmetric information of the early-stage start-ups, and technology innovation activities and employment capability in the credit rating formula.

• Journal of Environmental Science International
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• v.1 no.2
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• pp.125-136
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• 1992

Digestion of a municipal wastewater sludge by the anaerobic sequencing batch reactor (ASBR) was investigated to evaluate the performance of the ASBR process at a critical condition of high-solids-content fined. The reactors were operated at an HRT of 10 days with an equivalent loading rate of 0.8-1.5 gVS/L/d at 35$^{\circ}C$ The main conclusions drawn from this study were as follows: 1. Digestion of a municipal wastewater sludge was possible using the ASBR in spite of high concentration of settleable solids in the sludge. The ASBRS with 3- and 4-day cycle period showed almost identical high digestion performances. 2. No adverse effect on digestion stability was observed In the ASBRS in spite of withdrawal and replenishment of 30% or 40% of liquid contents. A conventional anaerobic digester could be easily converted to the ASBR without any stability problem. 3. Flotation thickening occurred in thicken step of the ASBRS throughout steady state, and floating bed volume at the end of thicken period occupied about 70% of the working volume of the reactor Efficiency of flotation thickening in the ASBRS could be comparable to that of additional gravity thickening of a completely mixed digester. 4. Solids were accumulated rapidly in the ASBR during start-up period. Solids concentrations in the ASBRS were 2.6 times higher than that in the completely mixed control reactor at steady state. Dehydrogenase activity had a strong correlation with the solids concentration. Dehydrogenase activity of the digested flu형e in the ASBR was 2.9 times higher than that of the flu형e in the control reactor, and about 25 times higher than that of the subnatant in the ASBR. 5. Remarkable increase in equivalent gas production of 52% was observed at the ASBRS compared with the control reactor in spite of similar quality of clarified effluent from the ASBRS and control reactor. The increase in gas production from the ASBRS was believed to be combined results of accumulation of microorganisms, higher driving force applied, and additional long-term degradation of organics continuously accumulated.

• Journal of Korean Society of Transportation
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• v.20 no.3
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• pp.31-39
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• 2002

The primary objective of this study is to develop a reliable method for estimating the left turn capacity at the signalized intersection. This study is performed during periods of congestion. Multi left turn lane(bay lane and exclusive lane) approaches are examined. When more than one left turn lane exists, traffic volumes are not distributed equally over each lane. The fundamental approach taken in this study is measuring headways on left turn lanes with altering the bay length from 20m to 120m. Left turn lane is divided into 3 sub-sections in this study. These are SLP section(start-up lost time Period), SFP section(saturation flow period), LSP section(lane selection period). Saturation flow rates are evaluated for each sub section periods. As a results of analysis, it has been confirmed that the left turn capacity can be estimated by left turn bay length and effective green time for left turn. The left turn bay length adjustment factor is suggested in this study.

• Asian-Australasian Journal of Animal Sciences
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• v.3 no.2
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• pp.121-123
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• 1990

A CRD experiment with unequal numbers of hens were assigned at random to three treatment groups, 1) separation of chicks from hen at 21 days after hatching 2) separation of chicks from hen at 7 days and 3) hens were allowed to brood the chicks(no separation) up to 10 weeks of age, to determine the productive and reproductive performance of hens and their chicks. The mean cycle length (one hatch to another) was 72.8 days for the 7-day group as compared with 87.7 days and 83.4 days for the 21-day and the no separation groups, respectively (p<.0l). The broody period was 28.5 days for the 7-day group compared with 43.9 and 42.6 days for the 21 days and the no separation groups, respectively (p<.0l). The end of the broody period to the start of lay varied from 8.0 to 8.7 days. The number of eggs laid per clutch were 12.3 for the 21-day group, compared with 11.5 and 10.1 for the 7-day and no separation groups, respectively (p<.05). This is due to the longer (p<.05) clutch length of the 21-day group as compared with the 7-day and no separation groups, respectively. The chicks separated from the hens at 21 and 7 days were heavier (p<.01) than the chicks not separated from the hens. Mortalities were highest (p<.05) for chicks separated at 7 days as compared with chicks separated at 21 days and those not separated. We concluded that separating chicks at 7 days from the hen gave the shortest cycle length and broody period, separating the chicks at 21 days gave the longest clutch length and the maximum number of eggs, separating the chicks at 21 and 7 days resulted in heavier chicks and separating the chicks at 7 days resulted in the highest mortality.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.3
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• pp.249-253
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• 2009

Langerhans cell histiocytosis(LCH), previously known as histiocytosis X, is rare, proliferative disorder in which the accumulation of pathologic Langerhans cell leads to tissue infiltration and destruction. The jaw is involved 10~20% of all LCH and most common oral symptoms are jaw swelling or a palpation mass. Most of subjects are males and disease appears to start before the age of 10 years. An 11 years old girl was referred from pediatric department. Histological examination confirmed the diagnosis LCH. She was treated intra-lesional injection of corticosteroid. The overall outcome was excellent. After a follow-up period of 20 month, the patient present with no evidence of residual disease on Panoramic view and whole body bone scan. We report this early recognized LCH case treated by corticoid injection in good progress with literature review.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.25-30
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• 2001

The liquid fuel film on the cylinder liner is believed to be a major source of engine-out hydrocarbon emissions in SI engines, especially during cold start and warm-up period. Quantifying the liquid fuel film on the cylinder liner is essential to understand the engine-out hydrocarbon emissions formation in SI engines. In this research, two-dimensional visualization was carried out to quantify liquid fuel film on the quartz liner in an SI engine test rig. The visualization was based on laser-induced fluorescence and total reflection. Using a quartz liner and a special lens, only the liquid fuel on the liner was visualized. The calibration technique was developed to quantify the fluorescence signal with the thickness gage and the calibration device. The fluorescence intensity increases linearly with increase in the fuel film thickness on the quartz liner. Using this technique, the distribution of the fuel film thickness on the cylinder liner was measured quantitatively for different valve lifts and injected fuel mass in the test rig.

• Archives of Reconstructive Microsurgery
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• v.10 no.2
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• pp.124-130
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• 2001

Both of latissimus dorsi and rectus abdominis muscles are workhorse for various reconstructive surgeries. These muscle flaps have been used widely for soft tissue coverage, tissue augmentation, and functional muscle transfer. However, the traditional method for muscle harvest requires a long incision that often results in an unsightly scar and becomes the main concern of the patient. The purpose of this study is to introduce our clinical experience of endoscopic harvest of latissimus dorsi muscle and rectus abdominis muscle, and to make comparison with traditional harvest of these two muscle flaps. Of the 13 rectus abdominis muscles free flaps, 6 muscles were harvested traditionally and 7 muscles were harvested with endoscopic assistance. Of the 21 latissimus dorsi muscle free flaps, 12 muscles were harvested traditionally and 9 muscles were harvested with endoscopic assistence. Follow up period was between 6 months and 24 months. The patients age ranged from 7 to 70 years old. The result revealed no statistically significant differences in the amount of intraoperative bleeding, incidence of postoperative hematoma and seroma, and the incidence of donor-site wound infection. However, patients feel less pain and start earlier and better movement after the operation with endoscopically assisted harvest. This technique is easy to learn, is safe, and can reduce substantially the donor site morbidity comparing traditional harvesting technique.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2001.01a
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• pp.211-218
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• 2001

This paper introduces a method of constructing expert systems in an integrated environment for automatic software design. This integrated environment may be applicable from top-level system architecture design, data flow diagram design down to flow chart and coding. The system is integrated with three CASE tools, FSD (Functional Structure Diagram), DFD (Data Flow Diagram) and structured chart PAD (Problem Analysis Diagram), and respective expert systems with automatic design capability by reusing past design. The construction way of these expert systems is based on systematic acquisition of design knowledge stemmed from a systematic design work process of well-matured developers. The design knowledge is automatically acquired from respective documents and stored in the respective knowledge bases. By reusing it, a similar software system may be designed automatically. In order to develop these expert systems in a short period, these design knowledge is expressed by the unified frame structure, functions of th expert system units are partitioned mono-functions and then standardized components. As a result, the design cost of an expert system can be reduced to standard work procedures. Another feature of this paper is to introduce the integrated environment for automatic software design. This system features an essentially zero start-up cost for automatic design resulting in substantial saving of design man-hours in the resulting in substantial saving of design man-hours in the design life cycle, and the expected increase in software productivity after enough design experiences are accumulated.