• Journal of the Korean Institute of Gas
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• v.2 no.1
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• pp.99-106
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• 1998

In order to investigate the impact properties of structural materials for LNG tank, instrumented Charpy impact tests were carried out at cryogenic temperatures. $9\%$ Ni steel showed a superior fracture resistance because of less degradation in toughness until 77 K. From the load-deflection curve obtained by an instrumented methods it was found that with the decrease of temperature from 173 K to 77 K, the peak load in the curve increased, but the total absorbed energy decreased. In addition, the energy absorbed during the crack growth was larger than one absorbed in the process of crack initiation. In SUS304L material, the energy absorbed in the process of the crack initiation was relatively large, but the energy absorbed in the process of crack growth was small, the behavior of absorbed energy was well agreed with the observations of the fracture surface which showed a relatively smooth fracture surface. The absorbed Charpy impact energy in the case of A5083 alloy was lower as compared with other steels, and some cracks were observed along the crack propagation direction at the fracture surface of 77 K.

• Journal of the Korea Concrete Institute
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• v.16 no.2 s.80
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• pp.139-146
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• 2004

Recently, interest on the performance of the construction temporary equipment have been greatly increased. Since the application of the 'Performance Test Code' for the equipment in 1992 according to the Industrial Safety and Health Act, a basic study of Steel Pipe Supports have been carried out for the last 2 years based on the Performance Test Results. The present code specification for the Steel Pipe Supports and research status are introduced. So far, total 849 specimen have been examined on their outer and inner pipe's length, thickness, their overlapping length, and their load carrying capacities. The test was conducted separately into two groups - used and new equipment, and it was found that the used ones revealed a decrease on their load carrying capacity, almost $10\%$ compared to the new ones. Considering this fact, it is strongly recommended to ensure the quality of the equipment before use at the jobsite. First of all, based on this basic investigation, the statistical values on the Steel Pipe Supports are suggested and further analysis on the effect of each component is in progress. It is, however, expected that this report can be used as a basic information on the Steel Pipe Supports.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.10
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• pp.57-63
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• 2014

This paper proposes an architecture of $3^{rd}$ order SDM(Sigma-Delta Modulator) with delayed feed-forward path in order to reduce the power consumption and area. The proposed SDM improve the architecture of conventional $3^{rd}$ order SDM which consists of two integrators. The proposed architecture can increase the coefficient values of first stage doubly by inserting the delayed feed-forward path. Accordingly, compared with the conventional architecture, the capacitor value($C_I$) of first integrator is reduced by half. Thus, because the load capacitance of first integrator became the half of original value, the output current of first op-amp is reduced as 51% and the capacitance area of first integrator is reduced as 48%. Therefore, the proposed method can optimize the power and the area. The proposed architecture in this paper is simulated under conditions which are supply voltage of 1.8V, input signal 1Vpp/1KHz, signal bandwidth of 24KHz and sampling frequency of 2.8224MHz in the 0.18um CMOS process. The simulation results are SNR(Signal to Noise Ratio) of 88.9dB and ENOB(Effective Number of Bits) of 14-bits. The total power consumption of the proposed SDM is $180{\mu}W$.

• Preventive Nutrition and Food Science
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• v.19 no.2
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• pp.115-123
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• 2014

In the current study, wheat flour was mixed with high quality cassava flour (HQCF) in several ratios: 90:10, 80:20, 70:30, and 60:40, and used to prepare 10%, 20%, 30%, and 40% National Root Crops Research Institute (NRCRI) cassava bread, respectively. 100% wheat bread was prepared as a control (100% wheat bread). Five bread samples were prepared per group. Antioxidant assays [i.e., 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging assay, reducing power assay] revealed that the bread samples had considerable antioxidant capacities. Substitution of wheat flour with HQCF at various concentrations resulted in dose dependent decreases in the mineral and protein contents of the resulting bread samples. The crude fiber content of the bread samples was minimal, while the carbohydrate content of the bread samples ranged from 43.86% to 48.64%. A 20% substitution of wheat flour with HQCF yielded bread samples with a general acceptability that was comparable to that of 100% wheat bread. The mean bacteria counts of the bread samples ranged from $2.0{\times}10^3CFU/mL$ to $1.4{\times}10^4CFU/mL$, while the fungal counts ranged from 0 CFU/mL to $3{\times}10^3CFU/mL$. There was a positive correlation between the DPPH antioxidant activities and the reducing powers of the bread samples ($R^2=0.871$) and a positive correlation between the DPPH antioxidant activities and the flavonoid contents of the bread samples ($R^2=0.487$). The higher microbial load of the NRCRI cassava bread samples indicates that these bread samples may have a shorter shelf life than the 100% wheat bread. The significant positive correlation between total flavonoid content and reducing power ($R^2=0.750$) suggests that the flavonoids present in the lipophilic fractions of the bread samples could be responsible for the reductive capacities of the bread samples.

• Wind and Structures
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• v.27 no.1
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• pp.11-27
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• 2018

The straight-cone steel cooling tower is a novel type of structure, which has a distinct aerodynamic distribution on the internal surface of the tower cylinder compared with conventional hyperbolic concrete cooling towers. Especially in the extreme weather conditions of strong wind and heavy rain, heavy rain also has a direct impact on aerodynamic force on the internal surface and changes the turbulence effect of pulsating wind, but existing studies mainly focus on the impact effect brought by wind-driven rain to structure surface. In addition, for the indirect air cooled cooling tower, different additional ventilation rate of shutters produces a considerable interference to air movement inside the tower and also to the action mechanism of loads. To solve the problem, a straight-cone steel cooling towerstanding 189 m high and currently being constructed is taken as the research object in this study. The algorithm for two-way coupling between wind and rain is adopted. Simulation of wind field and raindrops is performed with continuous phase and discrete phase models, respectively, under the general principles of computational fluid dynamics (CFD). Firstly, the rule of influence of 9 combinations of wind sped and rainfall intensity on flow field mechanism, the volume of wind-driven rain, additional action force of raindrops and equivalent internal pressure coefficient of the tower cylinder is analyzed. On this basis, the internal pressures of the cooling tower under the most unfavorable working condition are compared between four ventilation rates of shutters (0%, 15%, 30% and 100%). The results show that the 3D effect of equivalent internal pressure coefficient is the most significant when considering two-way coupling between wind and rain. Additional load imposed by raindrops on the internal surface of the tower accounts for an extremely small proportion of total wind load, the maximum being only 0.245%. This occurs under the combination of 20 m/s wind velocity and 200 mm/h rainfall intensity. Ventilation rate of shutters not only changes the air movement inside the tower, but also affects the accumulated amount and distribution of raindrops on the internal surface.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.7
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• pp.4379-4386
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• 2013

Projection of cancer incidence is essential for planning cancer control actions, health care and allocation of resources. Here we project the cancer burden at the National and State level to understand the magnitude of cancer problem for the various calendar years from 2011 to 2026 at 5-yearly intervals. The age, sex and site-wise cancer incidence data along with populations covered by the registries were obtained from the report of National Cancer Registry Programme published by Indian Council of Medical Research for the period 2001-2004. Pooled age sex specific cancer incidence rates were obtained by taking weighted averages of these seventeen registries with respective registry populations as weights. The pooled incidence rates were assumed to represent the country's incidence rates. Populations of the country according to age and sex exposed to the risk of development of cancer in different calendar years were obtained from the report of Registrar General of India providing population projections for the country for the years from 2001 to 2026. Population forecasts were combined with the pooled incidence rates to estimate the projected number of cancer cases by age, sex and site of cancer at various 5-yearly periods Viz. 2011, 2016, 2021 and 2026. The projections were carried out for the various leading sites as well as for 'all sites' of cancer. In India, in 2011, nearly 1,193,000 new cancer cases were estimated; a higher load among females (603,500) than males (589,800) was noted. It is estimated that the total number of new cases in males will increased from 0.589 million in 2011 to 0.934 million by the year 2026. In females the new cases of cancer increased from 0.603 to 0.935 million. Three top most occurring cancers namely those of tobacco related cancers in both sexes, breast and cervical cancers in women account for over 50 to 60 percent of all cancers. When adjustments for increasing tobacco habits and increasing trends in many cancers are made, the estimates may further increase. The leading sites of cancers in males are lung, oesophagus, larynx, mouth, tongue and in females breast and cervix uteri. The main factors contributing to high burden of cancer over the years are increase in the population size as well as increase in proportion of elderly population, urbanization, and globalization. The cancer incidence results show an urgent need for strengthening and augmenting the existing diagnostic/treatment facilities, which are inadequate even to tackle the present load.

• Korean Journal of Agricultural Science
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• v.23 no.1
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• pp.120-130
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• 1996

Concrete is the most commonly used structural materials, but in concrete construction, its self-weight represents a very large proportion of the total load on the structure, and there are clearly considerable advantages in reducing the density of concrete. This study was carried out to investigate the stress-strain properties of no-fines synthetic lightweight concrete with synthetic lightweight coarse aggregates. The used synthetic lightweight coarse aggregate were two types, one was expanded clay with grading 3~8mm, the other is pumice stone with grading 4.75~10mm. The results of this study were summarized as follows ; The static modulus of elasticity of the synthetic lightweight concrete was $1.8{\times}10^5kg/cm^2$ at type CE using the expanded clay and $1.6{\times}10^5kg/cm^2$ at type CL using the pumice stone. The dynamic modulus of elasticity was $1.9{\times}10^5kg/cm^2$(CE) and $2.0{\times}10^5kg/cm^2$(CL). The dynamic modulus of elasticity was 10~30% larger than that of the static modulus of elasticity. The load-time curves of synthetic lightweight concrete were shown approximately similar to each other type except for added foaming agent. The stress-strain curves in uniaxial compressive of synthetic lightweight concrete were similar to each other.

• Journal of the Ergonomics Society of Korea
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• v.31 no.3
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• pp.445-453
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• 2012

The aim of this paper was to prove that if the risk level in combined tasks was improved through evaluation of postural load of liquid weight measurement process, the workload level and ratio of exposure time would be changed, and the time of process would be seen concurrently. Background: According to results of epidemiological studies conducted by Korea Occupational Safety & Health Agency, 122 musculoskeletal disorders occurred during 1992 to 2008, in which manufacturing industry covers 96(78.7%) of total. However, this is an insufficient level and only occupies 39% based on the South Korea's manufacturing standard industrial classification(246 industries). Method: Firstly, the number of batches weighed on one day(460min) was investigated based on the work performed and Weight measured weekly. VCR recording was taken based on the level of liquid ingredients prescribed for 1batch using the Camcorder. After dividing a 356 sec video into 1 sec using the screen capture function in Gom player, the job classification was performed by analyzing the change of working postures, which revealed 148 working postures. Time measurement was decided by time of the postures was being maintained. Then, the REBA analysis was performed for the working postures. The ratio of Exposure time was calculated based on the measurement time and REBA Score. In addition, the recommendations were designed and implementation was carried out for the working postures with REBA Score higher than 3. Finally, after the intervention, REBA measurement, time measurement, and ratio of exposure time were calculated for the comparison of works before and after improvement. Results: The number of work elements was decreased by 30.4% from 148 to 103 after improvement. The results of time measurement showed that the time was reduced by 46.3% from 356 sec to 191 sec. And the ratio of exposure time was also improved by 52.1% from 0% to 52.1% after improvement. Conclusion: The reduction of time was found to improve the productivity of management. Furthermore, because the reduction of ratio of exposure time and the improvement of workload level are the improvement of discomfort, it would contribute to the improvement of the worker's psychological working posture. Application: These results would contribute to musculoskeletal disease prevention and management performance. Further studies for other industries would be needed based on this case study.

• 한국해양학회지
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• v.30 no.5
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• pp.371-381
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• 1995

To investigate the concentrations and transport patterns of particulate metals in river suspended matters, eighteen samples were collected from a fixed station located in the upper part of the Keum River through one year, and analysed for major elements (AI, Fe, P, Mn) and trace elements (Cr, Co, Ni, Cu, Zn, Cd, Pb, U). The contents of metals in suspended particulate matters (SPM) varied greatly with season and SPM load; maximum value in winter with low SPM level and minimum value in flood period and in spring Yangtze SPMs. The different trace metal level between rivers of Korea and China may be caused by the different geology of drainage basin(U) and by the different extent of anthropogenic input (Mn, Pb). Most of all particulate metals (>70%) except Mn, P and Cd were transported in the flood period with high water discharge and high suspended load. The magnitude of each transport phase (dissolved, non-detrital and detrital metals) was compared. The portions of labile metals (dissolved plus non-detrital metals) in the aquatic environment were in the range of 50%(Co) to 92%(Mn) of total metal transport and in the rank of Mn>Cd, U>Cu>Zn>Ni>Pb>Co.

• Journal of Korean Society of Forest Science
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• v.104 no.3
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• pp.488-494
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• 2015

This study aims to develop and apply a standard management self-diagnostic table for forestry households to better manage their astringent persimmon production. The diagnostic table consisted of 3 categories (general status of a forestry household, management performance indicators, level of management) and 18 subcategories. The current management status across 241 households was surveyed among 10 chief astringent persimmon producing municipalities. Scores from the 18 subcategories were aggregated for a total score to evaluate and compare different levels of management. The respondents scored an overall average of 57.4, 62% of which were placed between 40 and 60. Upon close examination Chungcheongnam-do scored a very low score in the 'management system-tree height' subcategory with respect to the average score potentially because of the large population of aged trees in the region. The national average in the 'production skills-time of fruit load adjustment' subcategory was only 1.96 because unlike sweet persimmons astringent persimmons adjust their own load by inducing physiological fruit drop. The national average in the 'management/sales skills-material purchase' subcategory was 2.01; over 60% of the respondents indicated a preference for independent selection and purchase for most materials. The households preferring a group purchase tended to utilize the regional co-op.