• The KSFM Journal of Fluid Machinery
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• v.10 no.2 s.41
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• pp.46-53
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• 2007

An improved performance characteristics analysis model of a regenerative pump is proposed in the present paper. For its low characteristic speed, a regenerative pump generates high head with low flow rate. However, the efficiency is fairly low due to the skin friction between impeller and casing. Also, the complexity of its internal flow pattern makes prediction of performance characteristics difficult. In the present research, a one-dimensional analysis model was improved with consideration of disc friction loss, minor loss, and modified flow length, and the result was proven to be close in range with the results from experiments.

• Journal of the Korean Society of Clothing and Textiles
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• v.24 no.7
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• pp.1044-1055
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• 2000

The purpose of this study is to suggest sizing chart for a clean room wear. 3 control dimensions(Stature, Bust girth, B.N.P.∼Wrist point length) were chosen as 3 axes of clean room wear size chart. A loss function was used to determined intervals of stature, Bust girth and B.N.P.∼Wrist point length of size chart, because the loss function introduces the concept of frequency to size chart for better customer's size satisfaction. From the size table whose intervals had been determined by a loss function. The 4 sizes individually were suggested for clean room wear size chart by sex. The 3 sizes individually were suggested for clean room head cover size chart by sex too. The suggested size chart would be considered more feasible than present size chart. Also they are suggested supply reference measurement chart relevant to clean room wear manufacturing for 13 most frequent sizes.

• Journal of Ocean Engineering and Technology
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• v.22 no.3
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• pp.1-7
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• 2008

In this study, a mathematical model for flaw with silt protector is proposed that adds a second-order energy loss term in the momentum equation. The three-dimensional numerical model was developed based on mathematical models and verified through comparison with flume test results. Loss coefficients were evaluated through the flume tests and applied to the numerical model. It was found through the investigation of various example cases that the downstream flow pattern was affected mainly by penetration of the silt curtain, not by the approach velocity, and also that the blocking effect of velocity was increased by the increase in mesh density of the silt curtain, below a certain mesh density. The blocking effect did not increase further above a certain mesh density.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.27 no.1
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• pp.25-33
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• 2021

This experiment was conducted to determine the effects of the pre- and post-harvest variable factors on the processed product of kimchi cabbage cultivated in semi-highland at summer time. Kimchi cabbage cultivar 'Chun Gwang' was grown in an open field and/or under a plastic greenhouse condition; it was stored at 0? after harvesting with low-density polyethylene (LDPE) film packaging. The pre-harvest characteristics growth parameters, fresh weight, head weight, no of leaves, leaf thickness, firmness, moisture content etc. were evaluated. The evaluated postharvest characteristics were fresh weight loss, appearance, trimming loss, SPAD value, moisture content and hue angle. The results show that the fresh weight and leaf thickness were higher in 'Chun Gwang' kimchi cabbages grown in the greenhouse than those in the field. However, the other evaluated factors were not affected by the type of cultural method. During the storage, the cabbage continued to decrease in fresh weight loss, trimming loss and moisture content. When compared to the kimchi cabbage showed significant difference in the fresh weight loss, trimming loss and moisture content during storage. It was confirmed that both cultural methods indoor- and outdoor did not show head growth parameters of 'Chun Gwang' kimchi cabbages on semi-high land at summer time. Although no difference in the growth before storage was observed, the evaluated characteristics like fresh weight loss etc. were influenced by cultural method as a pre-harvest factor. This study suggests that there were to be affected by pre-harvest factor during storage after harvest. In this study, an integrated management system combining relationship between processed agricultural products and their pre- and post-harvest factors.

• Journal of Internet Computing and Services
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• v.9 no.4
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• pp.1-10
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• 2008

In this paper, a packet scheduling algorithm, called the modified PLFS, is proposed for real-time traffic in IEEE 802.22 WRAN systems. The modified PLFS(Packet Loss Fair Scheduling) algorithm utilizes not only the delay of the Head of Line(HOL) packets in buffer of each user but also the amount of expected loss packets in the next-next frame when a service will not be given in the next frame. The performances of the modified PLFS are compared with those of PLFS and M-LWDF in terms of the average packet loss rate and throughput. The simulation results show that the proposed scheduling algorithm performs much better than the PLFS and M-LWDF algorithms.

• Nuclear Engineering and Technology
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• v.26 no.2
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• pp.179-189
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• 1994

A performance of reactor coolant pump in two-phase flow is examined using the pump geometric conditions and the performance of the pump in single-phase flow. Wall friction loss of the reactor coolant pump in single-phase flow is prdicted using the Truckenbrodt boundary layer theory, and the head loss in two-phase flow is predicted with calculated well friction loss and separation loss coefficients. The analysis results are compared with the Combustion Engineering pump test data. The effect of two-phase multiplier on the peak clad temperature in Loss-of-Coolant Accident is also examined using the RELAP5 and the results indicate the importance of its accuracy.

• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.2
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• pp.883-898
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• 2019

This paper employs computational tools to predict power increase (or speed loss) and propulsion performances in waves of KVLCC2. Two-phase unsteady Reynolds averaged Navier-Stokes equations have been solved using finite volume method; and a realizable k-ε model has been applied for the turbulent closure. The free-surface is obtained by solving a VOF equation. Sliding mesh method is applied to simulate the flow around an operating propeller. Towing and self-propulsion computations in calm water are carried out to obtain the towing force, propeller rotating speed, thrust and torque at the self-propulsion point. Towing computations in waves are performed to obtain the added resistance. The regular short head waves of λ/LPP = 0.6 with 4 wave steepness of H/λ = 0.007, 0.017, 0.023 and 0.033 are taken into account. Four methods to predict speed-power relationship in waves are discussed; Taylor expansion, direct powering, load variation, resistance and thrust identity methods. In the load variation method, the revised ITTC-78 method based on the 'thrust identity' is utilized to predict propulsive performances in full scale. The propulsion performances in waves including propeller rotating speed, thrust, torque, thrust deduction and wake fraction, propeller advance coefficient, hull, propeller open water, relative rotative and propulsive efficiencies, and delivered power are investigated.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.44 no.4
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• pp.182-190
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• 2018

Objectives: Head and neck squamous cell carcinoma (HNSCC) is the sixth most common malignancy worldwide. Inconsistency in various histopathologic features for predicting nodal metastasis and overall prognosis and a better understanding of molecular mechanisms of tumourigenesis have shifted the focus to a search for more definitive predictive markers. To identify the role of two immunohistochemical (IHC) markers, E-cadherin and cyclin D1, as predictive markers of aggressiveness in HNSCC and to assess clonal expansion of tumour cells. Materials and Methods: A total of 66 cases of HNSCC with neck node dissection were studied. IHC was performed on primary tumour sections and lymph nodes showing metastatic deposits. Histopathological parameters such as tumour grade and TNM stage together with nodal status were compared according to expression of the two markers. Fischer's chi-square test was used to assess the correlation between the two markers and histopathological parameters. Results: Out of 66 cases studied, 37 showed LN metastasis. Most of the patients were male, and the most common tumour site was buccal mucosa. We found a significant association between loss of E-cadherin and node metastasis (P<0.001) and higher TNM stage (P<0.001). Cyclin D1 overexpression was significantly associated with only nodal metastasis (P=0.007). No significant association with tumour grade was found for either marker. The subgroup of E-cadherin loss with cyclin D1 overexpression was associated with the maximum incidence of nodal metastasis and higher TNM stage, highlighting the importance of using a combination of these two markers. A significant association was noted between the expression of markers at the primary site and at nodal deposits, indicating clonal expansion. Conclusion: A combination of the two markers E-cadherin and cyclin D1 can predict prognosis in HNSCC, although tumour heterogeneity may affect this association in some cases.

• Safety and Health at Work
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• v.2 no.4
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• pp.348-354
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• 2011

Objectives: This cross-sectional study was performed in the Dental School of Prince of Songkla University to ascertain noise exposure of dentists, dental assistants, and laboratory technicians. A noise spectral analysis was taken to illustrate the spectra of dental devices. Methods: A noise evaluation was performed to measure the noise level at dental clinics and one dental laboratory from May to December 2010. Noise spectral data of dental devices were taken during dental practices at the dental services clinic and at the dental laboratory. A noise dosimeter was set following the Occupational Safety and Health Administration criteria and then attached to the subjects' collar to record personal noise dose exposure during working periods. Results: The peaks of the noise spectrum of dental instruments were at 1,000, 4,000, and 8,000 Hz which depended on the type of instrument. The differences in working areas and job positions had an influence on the level of noise exposure (p < 0.01). Noise measurement in the personal hearing zone found that the laboratory technicians were exposed to the highest impulsive noise levels (137.1 dBC). The dentists and dental assistants who worked at a pedodontic clinic had the highest percent noise dose (4.60 ${\pm}$ 3.59%). In the working areas, the 8-hour time-weighted average of noise levels ranged between 49.7-58.1 dBA while the noisiest working area was the dental laboratory. Conclusion: Dental personnel are exposed to noise intensities lower than occupational exposure limits. Therefore, these dental personnel may not experience a noise-induced hearing loss.

• Clinical and Experimental Otorhinolaryngology
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• v.11 no.4
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• pp.242-249
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• 2018

Objectives. Smoking is associated with hearing loss, while the correlation between tinnitus and smoking is not fully elucidated. This study aimed to evaluate risk factors of tinnitus in adolescents in terms of smoking, and we identified a rectifiable parameter that can be serially monitored. Methods. A cross-sectional study was conducted using data from the Korea National Health and Nutrition Examination Survey, with 2,782 participants aged 12 to 18 years, from 2008 through 2011. Participants with history of ear disease, hearing loss, and inadequate responses to questionnaires were excluded. We investigated the prevalence of tinnitus and tinnitus-related annoyance by questionnaire and sought potential risk factors in blood and urine tests and smoking history. Results. The prevalence of tinnitus in the 12- to 18-year-old population was 17.5%, with 3.3% reporting tinnitus-related annoyance. On univariate analysis, the prevalence of tinnitus increased with age (P<0.001) and was higher among girls (P=0.012). Blood tests and urinalysis showed significant correlation between tinnitus and red blood cell count, alkaline phosphatase levels, and urine cotinine (P=0.002, P<0.001, P=0.018, respectively). In multivariate analysis, the urine cotinine level was the only parameter associated with tinnitus (odds ratio, 1.000; 95% confidence interval, 0.999 to 1.000; P=0.038). Smoking was also significantly correlated with tinnitus (P=0.043), and amount of smoking with tinnitus-related annoyance (P=0.045). However, current smoking and past smoking were not correlated with tinnitus. Conclusion. Urine cotinine may be a rectifiable marker for management of tinnitus in adolescents. This suggests that smoking cessation should be incorporated in the management of tinnitus in adolescents.