• Journal of the Korean Society for Precision Engineering
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• v.17 no.6
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• pp.83-88
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• 2000

In machining large screws such as those of extruders, it takes long time to machine them on conventional machines which usually use single-tipped fixed tools. And it is also difficult to use an existing CAD/CAM coftware when trying to get over the problems of conventional machines and making use of CNC machines. In this paper, generation of machining program using rotational tools for large screws defined by longitudinal-section profile is descrebed. Use of rotational tools in machining plays an important role in saving machining time. In the sort of extruder screws, it is easy to define a screw shape by longitudinal-section profile, and by which improvement of dimensional accuracy can be expected. The CAM software developed in this paper is based on user's and designer's friendliness.

• The Korean Journal of Rheology
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• v.8 no.3_4
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• pp.187-198
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• 1996

최근에 본 연구자에 의해서 단축 스크류 공정에서 카오스 스크류라고 명명되어진 카오스 혼합장치가 성공적으로 개발되었다. 기하학적 조건이나 공정조건에 대한 설계변수로 카오스 스크류를 설계하기 위하여 체류시간, 포인카레 단면 그리고 혼합패턴등에 대한 계산 과 해석이 이루어져야 하는데 이를 단지 Runge-Kutta 방법에 의해 속도장을 적분한다면 상당한 계산시간이 소비된다. 이러한 수치문제를 극복하기 위하여 본논문에서는 새로운 사 상법을 제안한다. 이 방법으　 사용하면 벽면 근처의 특이점 영역에서도 수치문제가 해결된 다. 본 논문에서 제안하는 수치사상법은 Runge-Kutta 방법에 비하여 수치계산의 효율성과 정확도 면에서, 특히 유안요소법으로 얻은 속도장에 대하여 우수함이 밝혀졌다. 이러한 사상 법은 공간주기 유동장뿐만 아니라 시간주기 유동장에서 적용할수 있다.

• The Korean Journal of Rheology
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• v.10 no.3
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• pp.121-130
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• 1998

본 연구에서는 카오스 스크류에 대해 비선형 동력학적 모델을 도입하여 카오스가 일어나는 경로를 밝히고 이를 수치적으로 증명하였다. 배리어가 계속존재하는 경우를 적분 가능계로 정의하고 공간주기적 상공간에서 두 개의 호모클리닉 궤도를 포함하는 원환체를 적분가능계의 모델로 도입하였다. 주기적으로 삽입된 배리어 없는 영역을 교란 으로 취급하 여 해 사상을 도입하여 면적 보존의 포인카레 단면을 정의 하였다. 호모클리닉 궤도가 깨어 져 칸토로 집합을 이룸을 설명했고 내부의 원환체는 공진띠와 KAM띠를 이루며 혼합을 방 해함을 설명했다. 다변유한요소를 이용한 완전 3차원수치해석을 통해 회전수 x/3에 해당하 는 공진띠의 존재를 보이고 교란이 큰 경우에는 거의 모든 영역이 무작위적인 혼합을 보여 주는 카오스 영역으로 바뀜을 보였다.

• Korean Journal of Food Science and Technology
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• v.33 no.1
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• pp.45-49
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• 2001

This research was conducted to study the characteristics of the extruded products prepared from blends containing fixed amounts of frozen pollack (20%) and defatted soy flour (5%) and varying amounts of rice and corn flour using laboratory-scale single-screw extruder. Extrusion conditions were set at 27% feed moisture, $160^{\circ}C$ process temperature and 170 rpm screw speed. Results showed that there was almost no difference in proximate compositions among all extruded products. The product made from 100% rice flour had the highest expansion ratio, the lowest bulk density and the lowest shear force (P<0.05). Also, this product was the highest in L value and had the highest preference in sensory evaluation. Consequently, the addition of frozen pollack and defatted soy flour to rice flour could make desirable expanded extruded products. This study will form the basis for future development of rice snacks containing frozen pollack.

• The Korean Journal of Food And Nutrition
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• v.6 no.3
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• pp.178-188
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• 1993

This research was attempted to investigate changes in physicochemical properties of rice extrudate with added ginger powder extruded by single screw extruder. Graphic three dimensional analysis on response surface regression was used to evaluate effects of extrusion variables on quality factors of the extrudate according to two independent variables, ginger consent 0∼12%, moisture content 14∼26%. The summarized results are as follows : 1) Regarding proximate composition of rice extrudate with added ginger powder, as ginger powder content of raw material Increased, crude tat, crude protein, crude ash and crude fiber increased, while soluble nitrogen free extract decreased. 2) Graphic three dimensional analysis on response surface regression was conducted for each dependent variable which revealed statistically significant relationship with independent variables, 0∼120A ginger and 14∼26% moisture content. Expansion ratio had a critical point as moisture content changed. As ginger and moisture content Increased, bulk density, break strength and water absorption Index Increased, while water solubility Index decreased. The predicted maximum degree of gelatinization in 6.15% ginger and 15.56% moisture content is 88.27%, and lightness decreased as ginger content Increased. According to the microstructure for the cross section of extrudate obsorbed with image analyzer, air cell number and perimeter revealed saddle point, meanwhile total area and fractarea of air cell had critical points as moisture content changed. In view of the results, quality of rice extrudate with added ginger powder was optimum when rice flour was fed to the extruder with 2∼7% singer powder and 15∼20% moisture content.

• Preventive Nutrition and Food Science
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• v.6 no.3
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• pp.158-162
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• 2001

Blends of pork meat (20%), defatted soy flour (25%), and corn starch (48.61~53.71%) were prepared with or without additional non-meat ingredients, i.e., onion powder (1%), alone or in combination with carrot powder (1.5%) or extract (1.5%), or defatted oat flour (5%). All blends were formulated for 22.78% moisture, with water added where necessary. They were extruded using a laboratory single-screw extruder at 16$0^{\circ}C$ profess temperature and 170 rpm screw speed. The additional ingredients generally decreased product expansion and increased bulk density and shear force. When the product with no additional ingredient and the product with onion powder were evaluated by trained sensory panelists, \"grain complex\" was the most intense flavor note for both. With 1 % onion powder in feed, a distinct \"onion\" flavor note was detectable in extrudates. All the products may be considered \"healthful\" based on nutrient profiles.t; based on nutrient profiles.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.2
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• pp.292-298
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• 2001

This study was conducted to investigate physicochemical properties of extrudates combining 4 levels of squid (0, 3, 5 and 7%) with 3 levels of defatted soy flour (0, 5, and 10%). Blends were adjusted to moisture content of 27% and then extruded in a single-screw laboratory extruder at 170rpm screw speed and 16$0^{\circ}C$ barrel temperature. The extruded materials were dried at 6$0^{\circ}C$ for 8hr to a moisture content of 3~4% and refrigerated at 4$^{\circ}C$ for 12 hour before examination for textural properties, expansion ratio, bulk density, shear force and Hunter color. Expansion ratio of extrudates decreased as squid content increased whereas bulk density and shear force increased. Expansion ratio of extrudates was not significantly different by defatted soyflour level. Bulk density of products decreased as defatted soyflour content increased but shear force of products increased as defatted soyflour content increased. In scores of sensory hedonic evaluation of snacks, appearance, flavor, texture and overall acceptability values had lowered as squid level increased. Therefore, according to materials contents on extrudates increased, nutritional contents of this products increased and also shear force and bulk density in physical properties increased whereas expansion ratio decreased.

• Journal of the East Asian Society of Dietary Life
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• v.1 no.3
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• pp.305-311
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• 1991

The study was designed to investigate overall acceptability of rice extrudate with added ginseng flour extruded by single screw extruder. Graphic three dimension analysis on response surface regression was conducted for overall acceptability evaluated by balanced incomplete block design. Overall acceptability, which formed a saddle point, increased as moisture content increased at lower die temperature, and as moisture content decreased at higher die temperature. Critical values of each variable which indicated optimum response are 5.0% ginseng content, 17.8% moisture content and 104.6$^{\circ}C$ die temperature, and optimum inferred score of overall acceptability is 59.6 and 90. Key words: extrdate, overall acceptability, response surface regression analysis, balanced incomplete block method.

• Fibers and Polymers
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• v.7 no.1
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• pp.36-41
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• 2006

PVC and SAN are often mixed to compensate for the disadvantages of each polymer. Miscibility and thermal stability of PVC/SAN blend were investigated in this study by blending SAN polymer having 20, 24, 28, 32 % of acrylonitrile contents. Two polymers were mixed using a melt blending method with a single screw extruder. DSC thermogram was used to evaluate miscibility of the two polymers. SAN having 24 % of acrylonitrile showed the best miscibility with PVC. In order to evaluate degradation behavior, blended polymer was heat treated in DSC furnace and glass transition temperature was measured consecutively. Glass transition temperature increased continuously with annealing time due to degradation and cross-linking of polymer chains. Melt index of blended polymer was always higher than that of PVC.

• The Korean Journal of Food And Nutrition
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• v.23 no.1
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• pp.114-117
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• 2010

The effects of isolated soy protein(ISP) content on the physicochemical properties of extrudates from rice flour produced by a single-screw extruder were evaluated. The integrity index(II), nitrogen solubility index(NSI), rehydration ratio(RR), and density were measured as indices of the changes of physicochemical properties of rice extrudates. Increased amounts of ISP resulted in increased II but decreased RR and density. There was no change in the NSI value. It was concluded that the addition of ISP to the raw material could be helpful in texturization of rice extrudate.