• Tribology and Lubricants
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• v.38 no.5
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• pp.191-198
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• 2022

With the world's fast expanding energy usage comes a slew of new issues. Because one-third of energy is lost in overcoming friction, tremendous effort is being directed into minimizing friction. Surface texturing is the latest surface treatment technology that uses grooves and dimples on the friction surface of the machine to significantly reduce friction and improve wear resistance. Despite the fact that many studies on this issue have been conducted, most of them focused on parallel surfaces, with relatively few cases of converging films, as in most sliding bearings. This study investigated the lubrication performance of surface-textured inclined slider bearings. We analyzed the continuity and Navier-Stokes equations using a commercial computational fluid dynamics code, FLUENT. The results show the pressure and velocity distributions and the lubrication performance according to the number and orientation of rectangular dimples. Partial texturing somewhat improves the lubrication performance of inclined slider bearings. The number of dimples with the maximum load-carrying capacity (LCC) and minimum friction is determined. When the major axis of the dimple is arranged in the sliding direction, the LCC and friction reduction are maximized. However, full texturing significantly reduces the LCC of the slider bearing and increases the flow rate. The results have the potential to improve the lubrication performance of various sliding bearings, but further research is required.

• Journal of Veterinary Clinics
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• v.39 no.4
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• pp.162-167
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• 2022

To determine the prevalence of breed, age, and sex of canine primary glaucoma by comparing previous reports in Korea. We included the medical records of dogs diagnosed with primary glaucoma who visited the veterinary medical teaching hospital of Seoul National University (SNU) from January 2011 to December 2020 and investigated their breed, age, and sex. All the patients underwent a full ophthalmic examination. We analyzed the results using a binary logistic regression analysis based on the Jindo dog, which was close to the mean value of the primary glaucoma incidence rate. Of the 14,587 dogs treated at the veterinary medical teaching hospital of SNU, 107 (0.73%) were diagnosed with primary glaucoma. Glaucoma occurred in 14 breeds, including the American Cocker Spaniel, Shih Tzu, Maltese, Pomeranian, Jindo dog, Mixed Breed, Pekinese, Toy Poodle, Samoyed, Shiba Inu, Miniature Pinscher, Boston Terrier, Labrador retriever, and Yorkshire Terrier. The mean age of onset of primary glaucoma was 7.8 ± 2.3 years. Primary glaucoma was observed in 53 spayed females, 11 females, 38 castrated males, and five males. Regardless of neutralization, the ratio of females to males was 1.5:1. This study showed that primary glaucoma was significantly higher in American Cocker Spaniels and higher in Shih Tzus than other breeds in Korea; they had the highest incidence of primary glaucoma at 7 and 8 years of age, respectively. Therefore, the two breeds should be carefully monitored for the occurrence of primary glaucoma when they approach 7 years of age.

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.338-351
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• 2003

UV radiation is the most dangerous stress factor among permanent environmental impacts on human skin. Consequences of UV exposure are aberrant tissue architecture, alterations in skin cells including functional changes. Nowadays new kinds of outdoor leisure-time activities and changing environmental conditions make the question of sun protection more important than ever. It is necessary to recognize that self-confident consumers do not consider to change their way of life, they demand modern solutions on the basis of new scientific developments. In the past one fundamental principle of cosmetics was the use of physical and organic filter systems against damaging UV-rays. Today new research results demonstrate that natural protecting cell mechanisms can be activated. Suitable biological actives strongly support the protection function not from the surface but from the inside of the cell. A soy seed preparation (SSP) was proven to stimulate natural skin protective functions. The major functions are an increased energy level and the prevention of DNA damage. These functions can I be defined as biological UV protection. The tumor suppressor protein p53 plays a key role in the regulation of DNA repair. p53 must be transferred into the phosphorylated form to work as transcription factor for genes which are regulating the cell cycle or organizing DNA repair. A pretreatment with SSP increases the phosphorylation rate of p53 of chronically UV-irradiated human keratinocytes significantly. According to the same test procedure SSP induces a dramatic increase in the expression of the tumor suppressor protein p14$^{ARF}$ that is supporting the p53 activity by blocking the antagonist of p53, the oncoprotein Mdm2. Mdm2, a ubiquitin E3-ligase, downregulates p53 and at the same time it prevents phosphorylation of p53. The positive influence of the tumor suppressor proteins explains the stimulation of DNA repair and prevention of sunburn cell formation by SSP, which was proven in cell culture experiments. In vivo the increased skin tolerance against UV irradiation by SSP could be confirmed too. We have assumed, that an increased repair potential provides full cell functionality.y.

• Archives of Craniofacial Surgery
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• v.23 no.6
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• pp.256-261
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• 2022

Background: Treating panfacial fractures (PFFs) can be extremely difficult even for experienced surgeons. Although several authors have attempted to systemize the surgical approach, performing surgery by applying a unidirectional sequence is much more difficult in practice. The purpose of this study was to review the literature on PFF surgery sequence and to understand how different surgical specialists-plastic reconstructive surgery (PRS) and oral maxillofacial surgery (OMS)-chose sequence and review PFFs fixation sequence in clinical cases. Methods: The PubMed and Google Scholar databases were scoured for publications published up until May 2020. Data extracted from the studies using standard templates included fracture part, fixation sequence, originating specialist, and the countries. Bibliographic details like author and year of publication were also extracted. Also, we reviewed the data for PFFs patients in the Trauma Registry System of Dankook University Hospital from 2011 to 2021. Results: In total, 240 articles were identified. This study comprised 22 studies after screening and full-text analysis. Sixteen studies (12 OMS specialists and 4 PRS specialists) used a "bottom-top" approach, whereas three studies (1 OMS specialist and 2 PRS specialists) used a "top-bottom" method. However, three studies (only OMS specialists) reported on both sequences. In our hospital, there were a total of 124 patients with PFF who were treated during 2011 to 2021; 64 (51.6%) were in upper-middle parts, 52 (41.9%) were in mid-lower parts, and eight (6.5%) were in three parts. Conclusion: Bottom-top sequencing was mainly used in OMS specialists, and top-bottom sequencing was used at a similar rate by two specialists in literature review. In our experience, however, it was hard to consistently implement unidirectional sequence suggested by a literature review. We realigned the reliable and stable buttresses first with tailoring individually for each patient, rather than proceeding in the unidirectional sequence like bottom-top or top-bottom.

• International Journal of High-Rise Buildings
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• v.12 no.1
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• pp.93-105
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• 2023

Seismic isolation and vibration control techniques have been developed and put into practical use by challenging researchers and engineers worldwide since the latter half of the 20th century, and after more than 40 years, they are now used in thousands of buildings, private residences, highways in many seismic areas in the world. Seismic isolation and vibration control structures can keep the structures undamaged even in a major earthquake and realize continuous occupancy. This performance has come to be recognized not only by engineers but also by ordinary people, becoming indispensable for the formation of a resilient society. However, the dynamic characteristics of seismically isolated bearings, the key elements, are highly dependent on the size effect and rate-of-loading, especially under extreme loading conditions. Therefore, confirming the actual properties and performance of these bearings with full-scale specimens under prescribed dynamic loading protocols is essential. The number of testing facilities with such capacity is still limited and even though the existing labs in the US, China, Taiwan, Italy, etc. are conducting these tests, their dynamic loading test setups are subjected to friction generated by the large vertical loads and inertial force of the heavy table which affect the accuracy of measured forces. To solve this problem, the authors have proposed a direct reaction force measuring system that can eliminate the effects of friction and inertia forces, and a seismic isolation testing facility with the proposed system (E-isolation) will be completed on March 2023 in Japan. This test facility is designed to conduct not only dynamic loading tests of seismic isolation bearings and dampers but also to perform hybrid simulations of seismically isolated structures. In this paper, design details and the realization of this system into an actual dynamic testing facility are presented and the outcomes are discussed.

• Proceedings of the ESK Conference
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• 1997.04a
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• pp.56-60
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• 1997

The study of human erroneous actions has traditionally taken place along two different lines of approach. One has been concerned with finding and explaining the causes of erroneous actions, such as studies in the psychology of "error". The other has been concerned with the qualitative and quantitative prediction of possible erroneous actions, exemplified by the field of human reliability analysis (HRA). Another distinction is also that the former approach has been dominated by an academic point of view, hence emphasising theories, models, and experiments, while the latter has been of a more pragmatic nature, hence putting greater emphasis on data and methods. We have been developing a method to make predictions about error modes. The input to the method is a detailed task description of a set of scenarios for an experiment. This description is then analysed to characterise thd nature of the individual task steps, as well as the conditions under which they must be carried out. The task steps are expressed in terms of a predefined set of cognitive activity types. Following that each task step is examined in terms of a systematic classification of possible error modes and the likely error modes are identified. This effectively constitutes a qualitative analysis of the possibilities for erroneous action in a given task. In order to evaluate the accuracy of the predictions, the data from a large scale experiment were analysed. The experiment used the full-scale nuclear power plant simulator in the Halden Man-Machine Systems Laboratory (HAMMLAB) and used six crews of systematic performance observations by experts using a pre-defined task description, as well as audio and video recordings. The purpose of the analysis was to determine how well the predictions matiched the actually observed performance failures. The results indicated a very acceptable rate of accuracy. The emphasis in this experiment has been to develop a practical method for qualitative performance prediction, i.e., a method that did not require too many resources or specialised human factors knowledge. If such methods are to become practical tools, it is important that they are valid, reliable, and robust.

• Nuclear Engineering and Technology
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• v.55 no.2
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• pp.460-474
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• 2023

A simple but accurate mathematical model is crucial for dynamic simulations and controller design of helical coil once-through steam generator (OTSG). This paper presents a three-region movable boundary dynamic model of the helical coil OTSG. Based on the secondary side fluid conditions, the OTSG is divided into subcooled region (two control volumes), two-phase region (two control volumes) and superheated region (three control volumes) with movable boiling boundaries between each region. The nonlinear dynamic model is derived based on mass, energy and momentum conservation equations. And the linear model is obtained by using the transfer function and state space transformation, which is a 37-order model of five input and three output. Validations are made under full-power steady-state condition and four transient conditions. Results show good agreements among the nonlinear model, linear model and the RELAP5 model, with acceptable errors. This model can be applied to dynamic simulations and controller design of helical coil OTSG with constant primary-side flow rate.

• Journal of Electrochemical Science and Technology
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• v.14 no.1
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• pp.85-95
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• 2023

In recent years, solid-state Li metal batteries (SSLBs) have attracted significant attention as the next-generation batteries with high energy and power densities. However, uncontrolled dendrite growth and the resulting pulverization of Li during repeated plating/stripping processes must be addressed for practical applications. Herein, we report a plastic-crystal-based polymer/ceramic composite solid electrolyte (PCCE) to resolve these issues. To fabricate the one-side ceramic-incorporated PCCE (CI-PCCE) film, a mixed precursor solution comprising plastic-crystal-based polymer (succinonitrile, SN) with garnet-structured ceramic (Li₇La₃Zr₂O₁₂, LLZO) particles was infused into a thin cellulose membrane, which was used as a mechanical framework, and subsequently solidified by using UV-irradiation. The CI-PCCE exhibited good flexibility and a high room-temperature ionic conductivity of over 10^-3 S cm^-1. The Li symmetric cell assembled with CI-PCCE provided enhanced durability against Li dendrite penetration through the solid electrolyte (SE) layer than those with LLZO-free PCCEs and exhibited long-term cycling stability (over 200 h) for Li plating/stripping. The enhanced Li⁺ transference number and lower interfacial resistance of CI-PCCE indicate that the ceramic-polymer composite layer in contact with the Li anode enabled the uniform distribution of Li⁺ flux at the interface between the Li metal and CI-PCCE, thereby promoting uniform Li plating/stripping. Consequently, the Li//LiFePO₄ (LFP) full cell constructed with CI-PCCE demonstrated superior rate capability (~120 mAh g^-1 at 2 C) and stable cycle performance (80% after 100 cycles) than those with ceramic-free PCCE.

• Journal of the Korean Society of Food Culture
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• v.21 no.1
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• pp.42-50
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• 2006

The purposes of this study were to measure the job satisfaction levels of F&B(Food & Beverage) personnel in hotel by using JDI(Job Descriptive Index), to investigate relationships between demographic variables or job type and job satisfaction, to determine the relative importance of the five facets and to identify the effects of job satisfaction on turnover intention by hotel. Questionnaire was developed and distributed to 660 employees who are currently working in food & beverage department of hotel A (Domestic independent deluxe hotel) and hotel B(international chain deluxe hotel). A total of 498 questionnaires were usable; resulting in 75.5% response rate. The survey was conducted between March 16 to 27, 2000. As a result of analysis on job satisfaction, total JDI score was 136.57 out of full mark 210. Personnel of Hotel A was more satisfied significantly with work itself (p<.01), supervision (p<.001), co-worker (p<.01), total JDI (p<.001) than those of hotel B. Total JDI and work itself score were higher on employees of front of the house than those of back of the house in both of hotels. Payroll was the most important facet on job satisfaction. Finally, work itself (p<.001) and payroll (p<.05) had a significant effect on turnover intention in hotel A and work itself (p<.001), supervision (p<.05) and promotion (p<.05) did in hotel B. The findings indicated the necessity of human resource management apt to the vision of enterprise and the organizational culture.

• Asia Marketing Journal
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• v.14 no.3
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• pp.169-184
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• 2012

All firms require new stimulus to spurt growth. Therefore it is necessary to successfully develop new products and to employ appropriate marketing practices for the new products to enter and settle in the market. Binggrae, a Korean company that specializes in dairy and processed dairy products, introduced a ready-to-drink (RTD) coffee product, 'a Café la' to expand its business into the coffee market in 2008. Binggrae was a latecomer in the RTD coffee market but a Café la has shown an impressive average sales growth rate of 115% as of 2011 since the launch. Moreover, it is a steady bestselling coffee brand among the Polyethylene terephthalate (PET)bottle category. Binggrae found potential and opportunity in the growing coffee market and made efforts to develop a new product that can be differentiated from the existing products. The result was PET bottle coffee, which was more portable and convenient to drink than coffee products offered in cups or cans. PET bottle coffee is produced through the patented Aseptic Filing System, thus the original coffee flavor stays fresh when combined with milk and has a longer shelf life than coffee products in cups. Moreover, as the taste of coffee consumers has become more sophisticated, Binggrae developed a premium product by differentiating the product processing method and by using higher-quality Arabica beans. After launching the new product, the company also employed a well-designed communication strategy. First, Binggrae was able to confirm the level of market demand and market potential for the product by employing BTL (Below the Line) marketing strategies through the consumers' word-of-mouth. Afterwards, the company invested its resources for a full-scale ATL (Above the Line) marketing campaign. Later a Café la's TV commercial effectively portrayed the product's characteristics, and succeeded in raising consumer awareness of the product. As a result, a Café la has become the bestselling brand in the PET bottle coffee market. The successful new product marketing strategy of Binggrae'sa Café la offers many valuable implications for companies planning to launch new products in the future.