• Journal of Ocean Engineering and Technology
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• v.25 no.6
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• pp.86-90
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• 2011

The mining of imitated manganese noodles in 1000 m of seawater is planned for 2012. Thus, it is necessary to prepare the lifting pipes to be used for the test. Because of storage and expense constraints, flexible and economic HDPE pipe is being considered, making it necessary to test the structural safety. Material, pressure-chamber tests and finite element analysis of HDPE pipe for the 1000-m depth were performed. The tangential stiffness of HDPE was obtained through tension and three-point bending material tests and used for a structural analysis. FEA results show that the current sample pipe segment is safe for 1000 m of water pressure, and the stress result is also within the safe value. From the current results, the HDPE pipe seems to be acceptable only for the currently suggested constraints. However, more numerical and pressure tests need to be considered by applying additional physical conditions such as gravitational and hydrodynamic loads, external and internal fluid pressure, axial force induced ship motion, and heavy pump pressure to determine future usage.

• Structural Engineering and Mechanics
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• v.56 no.1
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• pp.49-56
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• 2015

Dynamic compaction (DC) is a useful method for improvement of granular soils. The method is based on falling a tamper (weighting 5 to 40 ton) from the height of 15 to 30 meters on loose soil that results in stress distribution, vibration of soil particles and desirable compaction of the soil. Propagation of the waves during tamping affects adjacent structures and causes structural damage or loss of performance. Therefore, determination of the safe or critical distance from tamping point to prevent structural hazards is necessary. According to FHWA, the critical distance is defined as the limit of a particle velocity of 76 mm/s. In present study, the ABAQUS software was used for numerical modeling of DC process and determination of the safe distance based on particle velocity criterion. Different variables like alluvium depth, relative density, and impact energy were considered in finite element modeling. It was concluded that for alluvium depths less than 10 m, reflection of the body waves from lower boundaries back to the soil and resonance phenomenon increases the critical distance. However, the critical distance decreases for alluvium depths more than 10 m. Moreover, it was observed that relative density of the alluvium does not significantly influence the critical distance value.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.2
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• pp.360-372
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• 2020

Objective: Specific genomic sites can be recognized and permanently modified by genome editing. The discovery of endonucleases has advanced genome editing in pigs, attenuating xenograft rejection and cross-species disease transmission. However, off-target mutagenesis caused by these nucleases is a major barrier to putative clinical applications. Furthermore, off-target mutagenesis by genome editing has not yet been addressed in pigs. Methods: Here, we generated genetically inheritable α-1,3-galactosyltransferase (GGTA1) knockout Yucatan miniature pigs by combining transcription activator-like effector nuclease (TALEN) and nuclear transfer. For precise estimation of genomic mutations induced by TALEN in GGTA1 knockout pigs, we obtained the whole-genome sequence of the donor cells for use as an internal control genome. Results: In-depth whole-genome sequencing analysis demonstrated that TALEN-mediated GGTA1 knockout pigs had a comparable mutation rate to homologous recombination-treated pigs and wild-type strain controls. RNA sequencing analysis associated with genomic mutations revealed that TALEN-induced off-target mutations had no discernable effect on RNA transcript abundance. Conclusion: Therefore, TALEN appears to be a precise and safe tool for generating genomeedited pigs, and the TALEN-mediated GGTA1 knockout Yucatan miniature pigs produced in this study can serve as a safe and effective organ and tissue resource for clinical applications.

• Journal of the Korean Society of Safety
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• v.34 no.4
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• pp.103-110
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• 2019

Underwater works are indispensable in the coastal and ocean engineering fields, and the reliance on manpower is higher than land works. Divers who work for a long time in a high-pressure underwater environment are always exposed to the risks of diving-related diseases. To prevent them, proper planning, operation, and management of diving by a supervisor with professional diving knowledge are required. This study provides the basic data for supervisors to plan, operate, and manage air diving for safe and efficient work in underwater construction sites. It is well-known that air diving simulations using the varying permeability model (VPM) require a longer decompression time as the water depth and the residence time in water increase. Therefore, it is crucial to have a proper surface interval through repetitive diving rather than single diving to improve the safety of the divers and the efficiency of underwater work. Furthermore, coastal and ocean engineers who manage and supervise underwater construction work must acquire expert knowledge on diving before they can plan, operate, and manage diving.

• International Journal of Advanced Culture Technology
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• v.9 no.2
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• pp.18-31
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• 2021

The purpose of the present study was to present evidence for driving interventions for the elderly by conducting programs that can improve visual perception and cognitive function in a driving simulator for elderly drivers and analyse their effects. Three elderly subjects who were 65 years or older, did not have physical and cognitive impairments, and were able to drive themselves participated in the present study. A total of 12 intervention sessions, of which subjects participated in 10 sessions of nine different visual perception and cognitive function programs available in a driving simulator, were conducted and pre- and post-program assessments were conducted (two assessments in total). The assessments included the evaluation of visual perception, frontal lobe function, concentration, safe driving behaviour, and self-efficacy. The results showed positive effects of the driving simulator program on the visual perception, frontal lobe function, concentration, safe driving behaviour, and self-efficacy of all subjects. Changes in the simulator results showed remarkable improvement in the response evaluation, judgment evaluation, and predictive power evaluation, but showed difficulties in interference tasks and depth perception in common. The results showed positive effects of driving simulator training on the driving ability of the elderly, and consistent provision of such training is expected to improve the quality of life of the elderly by securing the safety of driving and actively supporting social participation.

• Nuclear Engineering and Technology
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• v.54 no.2
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• pp.674-680
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• 2022

In the present study, radiation shielding and protection ability of prepared Flyash-lime-Gypsum (FaLG) bricks has been studied in terms of energy exposure build up factors and dose parameters. The energy exposure build up factors of Flyash-lime-Gypsum (FaLG) bricks have been calculated for the energy range of 0.015 MeV-15 MeV and for penetration depth upto 40 mfp directly using a new and simplified Piecewise Linear Spline Interpolation Method (PLSIM). In this new method, the calculations of G.P fitting parameters are not required. The verification and accuracy of this new method has been checked by comparing the results of exposure build up factor for NBS concrete calculated using present method with the results obtained by using G.P fitting method. Further, the relative dose distribution and reduced exposure dose rate for various radioactive isotopes without any shielding material and with Flyash-lime-Gypsum (FaLG) bricks have been calculated in the energy range of 59.59-1332 keV. On the basis of the obtained results, it has been reported that the prepared Flyash-lime-Gypsum (FaLG) bricks possess satisfactory radiation shielding properties and can be used as environmentally safe storage facilities for low level nuclear waste.

• The Korean Journal of Food & Health Convergence
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• v.7 no.6
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• pp.17-24
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• 2021

This study investigates the exercise-physiological changes in stages through the movement of the automatic stepper and to analyze the usefulness of the automatic stepper. For 18 male university students, out of 10 levels, 5 level and 10 level of automatic stepper exercise were performed. At each 10, 20, 30 minutes during exercise, 5 and 10 minutes after exercise stop the subjects were examined to analyze the changes in energy consumption after minutes, respiratory exchange rate, heart rate, oxygen consumption per body weight, METs, cumulative energy consumption, and lactic acid to verify the usefulness of the automatic stepper. The mean and standard deviation were calculated using the SPSS, and one-way ANOVA with repeated measure was performed to verify the difference in the mean between time periods. The LSD method was used for the post-hoc test, and the significance level was set to α = .05. There were no significant changes in both 5 and 10 level, but the cumulative energy consumption over time increased significantly. In addition, as a low-intensity exercise intensity is shown, a low increase in lactic acid indicated a safe exercise level. In future studies, in-depth studies of various variables through regular exercise programs are needed for those who need safe exercise.

• Journal of Agricultural Extension & Community Development
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• v.29 no.4
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• pp.203-224
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• 2022

This study aims to examine the educational needs of migrant farm workers and farmers in Korea. For developing survey instruments, content analysis of migrant workers & employer training programs, in-depth interviews with farmers and expert reviews had been conducted. Therefore, eight parts and twenty nine educational contents for migrant workers, five parts and twenty educational contents for farmers have been constructed. For data analysis, Borich analysis and The Locus for Focus Model were hired to analyze the educational needs assessment. Results showed that migrant workers' educational priorities were 'basic korean for farming, working attitude in farming, safety guidelines and first aid skills for rural life, safe use of pesticides and protective equipment, driving skills, safe use of agricultural machinery, operation & maintenance of agricultural machinery, pest control by crop', and for the farmers' were 'communication with migrant workers, trouble controls with employment, farming guidance, industrial accident cases and countermeasures, preventing disease and promoting mental health of migrant workers'.

• Geomechanics and Engineering
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• v.5 no.4
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• pp.363-377
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• 2013

Any structure constructed on the earth is supported by the underlying soil. Foundation is an interfacing element between superstructure and the underlying soil that transmits the loads supported by the foundation including its self weight. Foundation design requires evaluation of safe bearing capacity along with both immediate and long term settlements. Weak and compressible soils are subjected to problems related to bearing capacity and settlement. The conventional method of design of footing requires sufficient safety against failure and the settlement must be kept within the allowable limit. These requirements are dependent on the bearing capacity of soil. Thus, the estimation of load carrying capacity of footing is the most important step in the design of foundation. A number of theoretical approaches, in-situ tests and laboratory model tests are available to find out the bearing capacity of footings. The reliability of any theory can be demonstrated by comparing it with the experimental results. Results from laboratory model tests on square footings resting on sand are presented in this paper. The variation of bearing capacity of sand below a model plate footing of square shape with variation in size, depth and the effect of permissible settlement are evaluated. A steel tank of size $900mm{\times}1200mm{\times}1000mm$ is used for conducting model tests. Bearing capacity factor $N_{\gamma}$ is evaluated and is compared with Terzaghi, Meyerhof, Hansen and Vesic's $N_{\gamma}$ values. From the experimental investigations it is found that, as the depth of sand cushion below the footing ($D_{sc}$) increases, ultimate bearing capacity and settlement values show an increasing trend up to a certain depth of sand cushion.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.14
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• pp.147-157
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• 1973

I. The effect of excessive soil moisture(at the time of germination) on germination of barley and crop damage of herbicides was investigated. Machete(Butachlor) and TOK(Nitrofen) were treated, respectively, at the rate of 150g ai/10a on each pot whose different soil moisture content was controlled by suppling 30, 40, 50 and 60ml of water per 100gr of air-dried soil, respectively. The results are summarized as follows: 1. Excessive soil moisture beyond field moisture capacity caused great inhibition, from 20 to 100%, of the germination of barley even at untreated pots(check pots). Also, further development of root and growth of barley were greatly inhibited even though the seeds germinated. 2. The same tendency in inhibition of germination and growth as at untreated pots was observed at treated pots, too. As a whole, however, the damage were heavier at treated pots. II. Wanju naked spring barley was seeded on four different soils and covered with soil to a depth of 1 em, and then Machete, TOK, Saturn and HE-314 were treated at the rate of 180, 150 and 200, 150, and 250g ai/10a, respectively, and the effect of soil texture on crop damage of the herbicides was investigated. The results are summarized as follows: 1. Machete(emulsion and granule, at 180g ai/10a) The degree of crop damage was quite different from one soil texture to another: while almost no crop damage was observed on a clay loam soil regardless of the type of formulation, the damage became heavier as the soil texture became sandier as sandy clay loam, volcanic ash loam and sandy loam, and great inhibition of growth was observed on sandy loam soil. In general heavier damage was caused by the application of emulsion than by granular formulation. 2. TOK(Wettable powder, at 150, 250g ai/l0a) Almost the same tendency as in the application of Machete was observed, and the damage became heavier as the application rate increased. 3. Saturn(at l50g ai/l0a) No great difference in crop damage among soil textures was observed. 4. HE-3l4(at 250g ai/l0a) Almost no difference in crop damage among soil textures was observed at this rate of 250g ai/l0a. III. To study a difference of crop damage on soil covering depth(4 levels), 9 herbicides(TOK, MO, HE-3l4, Machete, Saturn, Simetryne, Simazine, Gesaran, Lorox) were treated on the pots with two different soils, and the effect of soil covering depth on crop damage of the herbicides was investigated. The results obtained in this experiment are summarized as follows: Light Clay Soil 1. The growth of barley in relation to depth of soil covering at check pots followed the order vigorous to weak; lcm>1.5cm>0.5cm>0cm. And in case of 0 and 0.5cm covering the growth of barley was very poor. 2. The damage at 0 and 0.5cm covering at treated pots was very severe, but Saturn, Machete, MO and TOK at 100 to l50g ai/l0a, respectively and He-3l4 at 250 to 375g ai/l0a were relatively safe to barley at the depths of lcm and above. 3. Simazine, Lorox and Simetryne caused slight damage even at 1.5cm covering. Sandy Loam Soil The growth of barley in relation to depth of soil covering at untreated pots followed the order, from vigorous to weak; 1.5cm 0.5cm 3cm 5cm. While MO was safe to barley at 1.5cm covering, for other chemicals more than 3cm covering was require for safe use. Machete and Saturn at 100g ai/l0a, and HE-3l4 at 250g ai/l0a was relatively safe at more than 3cm covering. Simazine, Lorox, Simetryne and Gesaran were unsafe on sandy soil regardless of covering depth.