• Korean Chemical Engineering Research
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• v.59 no.3
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• pp.305-315
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• 2021

An intermeshing corotating twin screw extruder is mainly used for compounding polymeric materials. Twin screw extruder can adopt modular-type screw configurations, which directly controls the quality and productivity of the products. The types, shapes, and specifications of the screw and kneading elements are summarized, and the effects of screw configuration on the processabiliy of the materials are discussed. The principles of screw configuration universally applied to mass production of general-purpose resins are explained, and the guidelines of screw combination according to the roles of feeding, melt mixing, and metering zones are listed. The strategies of screw combination suitable for various cases, such as side feeding of liquid additives or inorganic fillers, reactive extrusion, devolatilization process, production of products requiring bright color and transparency, and processing of materials with low apparent specific gravity, are presented.

• Journal of Pharmacopuncture
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• v.26 no.1
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• pp.44-52
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• 2023

Objectives: Dental caries is one of the most prevalent human diseases worldwide. The disease initiates with bacterial adherence to the tooth surface followed by the formation of dental plaques. Mutans streptococci and Candida albicans are principal oral microorganisms involved in the initiation and development of dental caries. Phytochemicals have been shown to possess promising antimicrobial properties against a wide range of microorganisms and can be used for the prevention and treatment of dental caries. Herein, we reviewed literature on plants that are traditionally used for their antimicrobial properties or possess promising anticariogenic activity. We selected aerial parts of Scrophularia striata (S. striata) and galls of Quercus infectoria (Q. infectoria) and investigated their antimicrobial activity against cariogenic microorganisms. Methods: Water soluble fractions were obtained from hydroalcoholic extracts of S. striata and Q. infectoria and their antimicrobial activity against Streptococcus mutans (S. mutans), Streptococcus sobrinus (S. sobrinus), and Candida albicans (C. albicans) was evaluated separately and in combination. The extracts were then used for preparing an herbal mouthwash whose stability and tannic acid content were evaluated over 60 days. Results: Q. infectoria gall extract possesses efficient antimicrobial activity that was synergistically enhanced in the presence of S. striata extract. Mouthwash prepared using these extracts showed desirable organoleptic characteristics, antimicrobial activity, and stability. Conclusion: Extracts of S. striata and Q. infectoria galls can be used together for preparing dental products with effective anticariogenic properties. Our study highlights the importance of extensive pharmacological investigations when using herbal products alone or in combination with other chemical substances.

• Fashion & Textile Research Journal
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• v.25 no.2
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• pp.221-229
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• 2023

This study aims to develop knee protectors that provide high safety and fitness, while incorporating a motion-adaptable 3D-printed pad. These protectors were evaluated by individuals who experience knee discomfort or pain. The results are as follows. First, the 3Dprinted pad design of a hexagonal mesh structure, which is modeled for excellent appearance and knee movement. Each unit of the mesh has a outer layer of 2mm thick, a spacer layer of 1 mm in diameter, and is connected by a 1.5 mm bridge. The bridge was extended up to 1.2 cm. Second, the knee brace was designed in three types - cylinder, strap, and combination by Universal design. Impact protection measurements of the three knee protectors demonstrated roughly 80% reduction in impact. Third, based on usability evaluation, cylinder type protectors have the highest ratings in most areas, primarily because of their ease of use. The strap type protector received positive reviews in terms of appearance and care, and the combination type provided stable knee protection. This study demonstrated the potential industrial application of 3D printing technology by designing and evaluating protective products for the human body. The results of this study are expected to aid knee protector manufacturers in developing practical products and promoting the development of protective equipment for other body parts or purposes.

• Journal of Intelligence and Information Systems
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• v.15 no.4
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• pp.183-200
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• 2009

Collaborative Filtering is one of the most used recommender systems. However, basically it cannot be used to recommend new products to customers because it finds products only based on the purchasing history of each customer. In order to cope with this shortcoming, many researchers have proposed the hybrid recommender system, which is a combination of collaborative filtering and content-based filtering. Content-based filtering recommends the products whose attributes are similar to those of the products that the target customers prefer. However, the hybrid method is used only for the limited categories of products such as music and movie, which are the products whose attributes are easily extracted. Therefore it is essential to find a more effective approach to recommend to customers new products in any category. In this study, we propose a new recommendation method which applies centrality concept widely used to analyze the relational and structural characteristics in social network analysis. The new products are recommended to the customers who are highly likely to buy the products, based on the analysis of the relationships among products by using centrality. The recommendation process consists of following four steps; purchase similarity analysis, product network construction, centrality analysis, and new product recommendation. In order to evaluate the performance of this proposed method, sales data from H department store, one of the well.known department stores in Korea, is used.

• Preventive Nutrition and Food Science
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• v.6 no.3
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• pp.163-169
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• 2001

To produce expanded, minimally hard extrudates from blends of raw pork meat (20%), defatted soy flour (25%), and corn starch using a single-screw extruder, various combinations of feed moisture, process temperature, and screw speed were evaluated. First series of extrusion runs were conducted according to a central composite rotatable design/response surface methodology (RSM). Upon assessing the full model for each response, insignificant terms were eliminated to determine final response surface models. Screw speed within the range evaluated was found to have no significant effect on expansion ratio (ER) or shear force (SF) of extrudates. Since examinations of the response surfaces and their generated grids of predicted values indicated that maximum ER and minimum SF were likely to be attained with a moisture-temperature combination outside the RSM experimental range, the second series of extrusion runs were conducted with several selected combinations of moisture and temperature to determine a practical optimum extrusion condition. The combination of 22.78% feed moisture, 16$0^{\circ}C$ process temperature, and 170 rpm screw speed was chosen as such a condition, and used in the final extrusion. The final product required less force to break than did commercial pretzel sticks.

• Journal of the Korea Fashion and Costume Design Association
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• v.13 no.2
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• pp.89-101
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• 2011

The economy blocking and price competitiveness caused by globalization has generated an on-going controversy of global sourcing among high-priced luxury brands. The consumers in the global market purchase luxury goods based on both craftsmanship and the reputation of luxury brands. Factors such as the origin, brand and pricing can affect the intention of consumers to buy luxury goods. This study analyzed the optimum brand combination using conjoint analysis. The analysis was based on the selection of origin, brand name and price as extrinsic factors among attributes of customer choice. These factors were subdivided into Italian and Chinese origins, Gucci, Prada, and Miu Miu in terms of brand names, and 450,000, 750,000, and 1,500,000 Won in terms of price levels. The result showed that origin was considered the most important factor followed by brand name and pricing. This tendency tells us that customers consider origin, brand name and price in that order when purchasing luxury brands. In regards to each factor, respondents preferred Italian to Chinese origins, the Gucci to Miu Miu brand name, and 750,000 to 450,000 won for price level. Generally, women in their 20s and 30s preferred products from advanced nations at a medium-level price.

• Toxicological Research
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• v.16 no.1
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• pp.89-94
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• 2000

Alpha-hydroxy acid(AHA) are used in cosmetic products as a pH adjuster, mild exfoliant and humectant-skin conditioner. Cosmetics containing higher concentration (30%) and lower pH (3.0) of AHA can cause side effects if it is applied without the prescription. For providing information on the safety of AHA and on human risk assessments we studied skin irritation effect of glycolic acid, one of the most commonly used AHA in guinea pigs. The skin irritation by glycolic acid was increased in a dose(10% to 70%), acidity (pH 2.5 to 5.5.) and length of exposure dependent manner (for up to 14 days), respectively. The combination treatment with UVB (0.4 or 3.0 J/$cm^2$) increased glycolic acid-induced skin irritation. Histological examination showed that hyperplasia of non-inflammatory cells in the epidermis of skin treated with high dose of glycolic acid (pH 3.0). There results show that glycolic acid increased skin irritation in a dose, length of exposure and pH dependent manner, respectively, in guinea pig, and the combination with UVB increased glycolic acid-induced skin irritation. The cell proliferation of non-inflammatory cell may be involved in high doses of glycolic acid-induced skin irritation. Long-term application of more than 30% of glycolic acid (pH 3.0) may cause skin irritation.

• Biomolecules & Therapeutics
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• v.23 no.2
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• pp.174-179
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• 2015

BP201, porcine lung tissue-derived phospholipids, consists of phosphatidylcholine as a major phospholipid species. BP201 promoted hair growth after application onto the shaved backs of BALB/c and C3H mice. Its effect was enhanced when applied together with minoxidil (MNX) in C3H mice. When the tissue specimens prepared from the shaved skins of BP201-treated and control mice were microscopically examined, the total numbers of hair follicles in both anagen and telogen phases of BP201-treated mice were significantly higher than those of control mice. The numbers of hair follicles in the anagen phase of BP201-treated mice were also higher than those of control mice. In combination with MNX, BP201 further increased the total number of hair follicles, but did not alter the percentage of hair follicles in the anagenic phase. BP201 also increased the proliferation of human hair follicle dermal papilla cells. Collectively, BP201 possesses hair growth promoting potential, which would suggest its use singly or in combination for hair growth products.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.669-674
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• 2001

Electric Arc Furnace Dust (EAF Dust) Is residual dust produced during the manufacturing of metal products from heavily heated electric arc furnace. Many researches have focused on recycling and reusing EAF Dust for industrial and construction purposes. However, most of these researches were aimed at obtaining useful heavy metal powders by treating toxic metallic materials in EAF Dust. Also, few researches dealt with using EAF Dust as admixture in concrete mixture (i.e., slag dust). In this study, EAF Dust is used as admixture in concrete mixture content considering economical feasibility and construction applicability. The concrete specimens mixed with EAF Dust is then tested in compression and tension to study its strength and ductility as well as its failure mechanism. The compression and tension (by split cylinder test) test results are compared to the results from the specimens without EAF Dust to understand the chemical stability and mechanical characteristic of concrete specimens with EAF Dust. For the experiment, 6 types of admixture added concrete were studied: ⑴Combination of EAF Dust and blast-furnace slag in 1 to 1 ratio, ⑵Combination of EAF Dust and blast-furnace slag in 1 to 2 ratio, ⑶EAF Dust only, ⑷blast-furnace slag only, ⑸fly ash only, and ⑹no admixture. The experimental results show that the strength of EAF Dust added specimen has lower early age strength but higher 28 day strength when compared to other specimens. Also, the Elastic Modulus of EAF Dust is higher(28 days) than other specimens. The study results prove that EAF Dust can be used as an effective admixture in concrete for specific usages.

• Journal of Korean Institute of Industrial Engineers
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• v.33 no.4
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• pp.393-401
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• 2007

Affective aspects of design attributes such as color, Pattern, and texture are important to the overall impression and the success of interior products. Among all the interior materials, wallpapers and flooring materials take up largest construction area and they are main components in creating affective impression for customers. This study aims to investigate the relationship between luxuriousness and related affective variables and design elements of wallpapers and flooring materials. The approach consists of 3 steps: (1) selecting related affective features and product design attributes through a literature survey, opinion of expert panel, and focus group interview, (2) conducting evaluation experiments, and (3) developing Kansei models using multivariate statistical analysis and analyzing critical attributes. Evaluation experiment was conducted using a questionnaire made up of 7-point scale and 100-point scale and 30 housewives and 20 interior designers participated in the evaluation experiment. The result of evaluation was analyzed through principal component regression and quantification I analysis. As a result of analyzing the survey data, the relationship between luxuriousness and related affective features and product design attributes was identified, moreover a optimal combination of the design component was identified. Consequently, it is expected that the results of the study would be a basis of the concept of emotion-based design by giving insights about how customers perceive the luxuriousness and suggesting the optimal combination, and providing specific quantitative design guidelines.