• Korean Journal of Food Science and Technology
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• v.31 no.5
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• pp.1196-1202
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• 1999

This work was to determine the microbial and physico-chemical changes of HTST-pasteurized soymilk using microwave energy. Soymilk was HTST pasteurized$(at\;90^{\circ}C\;for\;20\;sec)$ by three methods: by heating in a stainless steel tube immersed in a hot water bath(MP0), by heating in a microwave cavity to a defiled temperature and then holding in a hot water bath(MP1), and by both heating and holding in a microwave cavity(MP2). The microbial quality based on the total plate count was in the order of MP0, MP2 and MP1. The three samples pasteurized by different methods showed the similar microbial quality with respect to the coliform count, psychrotrophic bacterial count and phosphatase activity. The destruction of trypsin inhibitor was in the order of MP0, MP1 and MP2. There were no significant differences in pH, titratable acidity, viscosity and vitamin $B_2$ content before and after pasteurization and among the different pasteurization methods. The similar or higher quality retention of the MP1 or MP2 supports the possibility of using microwave energy for the HTST pasteurization of soymilk and other fluid food products.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1518-1522
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• 1999

This work was to determine the quality changes of milk with respect to the chemical components when HTST pasteurized by microwave energy. Raw milk was HTST pasteurized $(at\;72^{\circ}C\;for\;15\;sec)$ by three methods; by heating in a stainless steel tube immersed in a hot water bath (MP0), by heating in a microwave cavity to a desired temperature and then holding in a hot water bath (MP1) and by both heating and holding in a microwave cavity (MP2). There were no significant differences in pH and titratable acidity before and after pasteurization and among the different pasteurization methods. MP1 or MP2 showed better retention or less destruction than MP0 with respect to vitamin A, vitamin $B_1$, ascorbic acid and lysine content. The higher retention of nutrients of the MP1 or MP2 supports the possibility of using microwave energy for the pasteurization of milk and other fluid food products.

• Safety and Health at Work
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• v.14 no.1
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• pp.66-70
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• 2023

Background: Online teaching and learning extend the duration of using gadgets such as mobile phones and tablets. A prolonged usage of these gadgets in a static position can lead to musculoskeletal disorders (MSD). Therefore, this study aims to identify the risk factors related to musculoskeletal symptoms while using gadgets during work from home due to the COVID-19 pandemic. Method: A cross-sectional survey with online-based questionnaires was collected from the University of Indonesia, consisting of lecturers, students, and managerial staff. The minimum number of respondents was 1,080 and was defined by stratified random sampling. Furthermore, the dependent variable was musculoskeletal symptoms, while the independent were age, gender, job position, duration, activity when using gadgets, and how to hold them. Result: Most of the respondents had mobile phones but only 16% had tablets. Furthermore, about 56.7% have used a mobile phone for more than 10 years, while about 89.7% have used a tablet for less than 10 years. A multivariate analysis found factors that were significantly associated with MSD symptoms while using a mobile phone, such as age, gender, web browsing activity, work, or college activities. These activities include doing assignments and holding the phone with two hands with two thumbs actively operating. The factors that were significantly associated with MSD symptoms when using tablets were gender, academic position, social media activity, and placing the tablet on a table with two actively working index fingers. Conclusion: Therefore, from the results of this study it is necessary to have WFH and e-learning policies to reduce MSD symptoms and enhance productivity at work.

• Journal of the Korean Society for Library and Information Science
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• v.18
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• pp.55-98
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• 1990

This research attempts to verify the hypothesis that the workers in the small-and medium-sized industries use more informal information channels than formal ones do to get the information necessary to industrial activities. Information sources are divided by the internal and the external ones and these are sub-divided by their acquiring channels, publishers and holding institutions. It is intended to investigate the information sources according to the use frequency, age, origin and format of documents used. The degree of benefit to the workers in their practical work through the use of information sources and the use frequency of information sources by the department and years of experience are also investigated. The data to test the hypothesis was collected through the questionnaires distributed to the workers in 300 sampled firms from June 5 to June 20, The following facts have been verified as the result : 1. Workers in industries acquire information mainly through the contacts with the colleagues or superiors in their departments, and the junior workers depend more on the colleague and superiors than senior workers are. 2. Among the documents published internally, the ones from the research and development departments are mostly used. The documents issued by the worker's own departments are also frequently used and the senior workers, the more frequently use the internal publications than the junior workers do. 3. Among the internal documents stored in various places in the industries, the documents kept in the worker's own departments are used most frequently. The senior workers the more use privately owned documents than the junior workers do. 4. As far as the external channels are concerned, information is obtained mainly through suppliers of equipment and raw materials and the use frequency of information channels varies according to department. The senior workers the more receive information through supporting institution, seminar and exhibition than the junior workers do. 5. Among the external publication, the ones published by the industrial supporting institutions are heavily used and the workers in research and developments frequently use the external publications. 6. The documents held in governmental industrial institutions and industrial supporting institutions are heavily used compared with the ones stored in other external institutions. The holding places of frequently used documents vary according to the working departments. 7. The degree of benefit to practical work performance resulted from the internal information use is less than by the use of external information. 8. The documents published more than five years ago are more used than the ones of less than five years, Korean and Japanese documents are used frequently and catalogues, patents and standards are used to a great extent. The documents are used differently in accordance with work departments.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.322-325
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• 2007

Dent resistance is an important characteristic to avoid damage on automotive outer panels. From a practical point of view, dents can be caused in a number of ways. Considering doors as an example, denting can occur from stone impacts or from the careless opening of an adjacently parked vehicle door. Denting can occur where the door surface is smooth and may not have sufficient curvature to resist dent. These exterior body parts are designed to improve dent resistance using a combination of work hardening and bake hardening. In brief, dent is affected by the shape of the parts and the material properties such as yield strength, strain and thickness. In this work, forming of door outer panel is investigated by Taguchi method. Main parameters are yield strength, thickness, blank size, blank holding force and so on. For the given value of design parameters, forming analysis of the thirty six cases are carried out according to L18 orthogonal array. After comparing the performance by simple conversion of simulation results into dent resistance, the final suggestion of the forming parameters is verified for the best improvement of dent resistance.

• Journal of the Korean Society for Heat Treatment
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• v.14 no.3
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• pp.155-159
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• 2001

The thermal shock resistance has been investigated and compared in three hot-work tool steels. The resistance to thermal shock is first of all a matter of good toughness and ductility. Therefore, a proper hot-work tool steel should be characterized by high fracture strength and high temperature toughness. In this study, new test method is proposed to measure the thermal shock resistance. New method is basically based on Uddeholm' thermal shock test but some modification has been properly applied. Based on these results, some critical temperature($T_{fractures}$) at which fracture occur can be measured to characterize the thermal resistance of the materials. The specific values of ${\Delta}T$, the temperature difference between holding temperature and $T_{fractures}$, has been successfully used as a measure of the thermal shock resistance in this study, the results showed that the thermal shock method used in this study was properly modified.

• Journal of Korean Society of Rural Planning
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• v.13 no.2
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• pp.27-38
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• 2007

This study, a sub-one of comprehensive research work titled under "A Evaluation System of Amenity / Disamenity Elements in Rural Villages", tried to propose a rational methodology for development of rating tabulation for evaluation of amenity / disamenity elements in rural villages. The system developed in the study has the formalized rating grades between 2 and 5 for convenience/simplification of analysis work. For each evaluation element in the lowest order of the system, 5 types of rating technique were arranged, which were based on statistical analysis using mean and standard deviation values, its existence or not, relative significance of its holding volume and quality, synthesized weight scale of its quality and quantity, and the others. And, standardized 4-steps procedure for rating tabulation was proposed. Finally, through case studies of 4 sample villages representing the flat-plain, upland, seashore and periurban rural areas, the applicability of this rating tabulation system was verified.

• Particle and aerosol research
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• v.5 no.4
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• pp.159-170
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• 2009

A depth filter medium was newly designed in order to achieve high collection of dust and low pressure drop in this work. Multilayer depth filter media consist of an upstream layer of highly porous structure which allows particles to pass through and to follow by one or more downstream layers to hold the particles inside the media. For each filter media, flat sheet and pleated module were made of newly developed depth filter media and filter media of commercial products. Commercial depth filter cartridge for gas turbine air intake cleaning were used as reference for filtration area and pleat geometry of pleated modules. This work attempts to evaluate and compare the newly developed depth filter medium and two commercial filter media in terms of filtration parameters such as air permeability, initial pressure drop, particle retention and pressure drop variation with dust loading. According to the close examination the newly developed depth filter showed better performance compared to the commercial depth filter media.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.4 s.97
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• pp.110-115
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• 1999

The surface gloss of an injection molded part is one of the most significant point for evaluating the quality of products appearance. The effects of process condition on the gloss of ABS(Acrylonitrile-Butadiene-Styrene) molded part were investigated in this work. The measurements of gloss and morphology on the surface of molded part were carried out with different melt temperature, mold temperature, mold surface roughness, injection pressure and holding pressure. Gloss had a maximum value with melt temperature in the range of 210 to 220 ${^\circ}C$ and with mold temperature 40 to 50${^\circ}C$ and with injection pressure 80~90 MPa, respectively. Melt temperature was shown to have the largest effect on gloss in our work. Gloss was not improved in the region of melt temperature 240${^\circ}C$ above and of mold temperature 60${^\circ}C$ above. It was concluded that the variation of gloss was mainly caused by rubber particles migration under shear stress not by their aggregation or necklace.

• Transactions of Materials Processing
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• v.16 no.4 s.94
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• pp.254-259
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• 2007

Dent resistance is an important characteristic to avoid damage on automotive outer panels. From a practical point of view, dents can be caused in a number of ways. Considering doors as an example, denting can occur from stone impacts or from the careless opening of an adjacently parked vehicle door. Denting can occur where the door surface is smooth and may not have sufficient curvature to resist dent. These exterior body parts are designed to improve dent resistance using a combination of work hardening and bake hardening. In brief, dent is affected by the shape of the parts and the material properties such as yield strength, strain and thickness. In this work, forming of door outer panel is investigated by Taguchi method. Main parameters are yield strength, thickness, blank size, blank holding force and so on. For the given value of design parameters, forming analysis of the eighteen cases are carried out according to L18 orthogonal array. After comparing the performance by simple conversion of simulation results into dent resistance, the final suggestion of the forming parameters is verified for the optimal improvement of dent resistance.