• Title/Summary/Keyword: Trimmed surface

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Three Dimensional Last Data Generation System Utilizing Cross Sectional Free Form Deformation (단면 분할 FFD를 이용한 3D 라스트 데이터 생성시스템 개발)

  • Kim, Si-Kyung;Park, In-Duck
    • Journal of Institute of Control, Robotics and Systems
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    • v.11 no.9
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    • pp.768-773
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    • 2005
  • A new approach for human foot modelling and last design based on the cross sectional method is presented in this paper. The proposed last design method utilizes the dynamic trimmed parametric patches for the foot 3D data and last 3D data. The cross section a surface of 3D foot for the 3D last, design modeling of free form geometric last shapes. The proposed last design scheme wraps the 3D last data surrounding the measured 3D foot data with the effect of deforming the last design rule The last design rule of the FFD is constructed on the FFD lattice based on foot-last shape analysis. In addition, the control points of FFD lattice are constructed with cross sectional data interpolation methods from the a finite set of 3D foot data. The deformed 3D last result obtained from the proposed FFD is saved as a 3D dxf foot data. The experimental results demonstrate that the last designed with the proposed scheme has good performance.

ADAPTATION OF RESIN-MODIFIED GLASS IONOMER CEMENT TO DENTIN (상아질에 대한 광중합형 글라스 아이오노머 시멘트의 접합도)

  • Cho, Young-Gon
    • Restorative Dentistry and Endodontics
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    • v.22 no.2
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    • pp.792-800
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    • 1997
  • The purpose of this study was to evaluate the adaptation of self-cured glass ionomer cement and resin-modified glass ionomer cement and polyacid-modified resin composite, which are light-cured giass ionomer cements, to dentin surface. Twelve extracted human maxillary and mandibular molar teeth were used in this study. The entire occlusal dentin surfaces of teeth were exposed with Diamond Wheel Saw and smoothed with sand papers (300, 600, 1200grits). They were randomly assigned into 3 groups according to glass ionomer cements used; Control group- Fuji II, Expeimental group 1 - Fuji II LC, Expeimental group 2 - Dyract. According to the manufacturer's directions, three glass ionomer cements were bonded to exposed dentin surfaces of the tooth crown and cured. Crowns and glass ionomers were trimmed after 24hrs and sectioned horizontally and vertically with diamond saw. The interface of glass ionomer cements and dentin was examined under SEM. The results were as follows : 1. Good adatation between glass ionomer cement and dentin on the horizontal section was showed in control and experimental group 1, but the gap of $20{\mu}m$, which was observed distinct separation between glass ionomer cement and dentin, was showed in experimental group 2. 2. Good adatation between glass ionomer cements and dentin on the vertical section was showed in control and experimental group 1, but the gap of 80-$100{\mu}m$ was showed in experimental group 2. 3. Cohesive fracture within glass ionomer cements in control and experimental group 1 was showed, but no cohesive fracture was showed in experimental group 2.

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Optimal Control of Chill layers through Regulation of Temperature on Shot Sleeve in Aluminum High Pressure Diecasting (Al고압주조공법에서 사출슬리브 온도 조절을 통한 Chill layer의 최적 제어)

  • Park, Jin-Young;Kim, Eok-Soo;Park, Yong-Ho;Park, Ik-Min
    • Korean Journal of Materials Research
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    • v.16 no.11
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    • pp.698-704
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    • 2006
  • In this study, the effect of chill layers occurred in shot sleeve on the molten metal filling was analyzed through computer simulation. The behavior of chill layers with temperature variation of shot sleeve set from 200 to $280^{\circ}C$ was also investigated. The simulation results showed the chill layers set in the in-gates during the injection process change the main filling direction and cause turbulent flow pattern, resulting in porosities inside the castings. The amount of chill layers with the increasing temperature of shot sleeve was considerably reduced. Particularly, at the setting temperature of $280^{\circ}C$ by heat control unit, the biggest reduction in chill layers, excellent trimmed surface and the highest density were achieved, suggesting that as the optimal sleeve condition in aluminum high pressure diecasting, especially for highly complex parts like valve body.

Numerical simulation of propeller exciting force induced by milling-shape ice

  • Wang, C.;Li, X.;Chang, X.;Xiong, W.P.
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.11 no.1
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    • pp.294-306
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    • 2019
  • On the basis of the Computational Fluid Dynamics technique (CFD) combined with the overlap grid method, this paper establishes a numerical simulation method to study the problem of ice-propeller interaction in viscous flow and carries out a simulation forecast of the hydrodynamic performance of an ice-class propeller and flow characteristics when in the proximity of milling-shape ice (i.e., an ice block with a groove cut by a high-speed revolving propeller). We use a trimmed mesh in the entire calculation domain and use the overlap grid method to transfer information between the domains of propeller rotation calculation and ice-surface computing. The grid is refined in the narrow gap between the ice and propeller to ensure the accuracy of the flow field. Comparison with the results of the experiment reveals that the error of the hydrodynamic performance is within 5%. This confirms the feasibility of the calculation method. In this paper, we calculate the exciting force of the propeller, analyze the time domain of the exciting force, and obtain the curve of the frequency domain using a Fourier transform of the time-domain curve of the exciting force. The existence of milling-shape ice before the propeller can greatly disturb the wake flow field. Unlike in open water, the propeller bearing capacity shows a downward trend in three stages, and fluctuating pressure is more disordered near the ice.

Prediction of fishing boat performance using computational fluid dynamics (전산 유체 해석을 이용한 어선의 속도 성능 추정)

  • Kim, In-Seob;Park, Dong-Woo;Lee, Sang-Bong
    • Journal of Advanced Marine Engineering and Technology
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    • v.40 no.7
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    • pp.574-579
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    • 2016
  • Grid systems used in previous studies were determined to be valid only if the length between the perpendiculars in a model ship was in the range of 6-8 m, and the maximum dynamic trim angle was smaller than $1^{\circ}$. The application of the grid system to a small fishing boat can create numerical instability because the dynamic trim of small boats is generally larger than $3^{\circ}$, and their Froude numbers are in the range of 0.3-0.8. In the present study, resistances of a small fishing boat were stably obtained by reducing the length between the center of buoyancy and the inlet boundary of the numerical domain, and by refining grid cells vertically in a region that would be swept by a free surface. The effective power of the small fishing boat was predicted based on the ITTC-1978 two-dimensional analysis. By using the results of previous towing tank tests, the coefficient of quasi-propulsive efficiency and the brake horsepower at a design draft were calculated.

Measurement of Contact Angle and Bond Strength Using 3 Different Self-Etching Primer (3종의 자가부식 프라이머의 상아질계면 접촉각 및 미세인장결합강도에 관한 연구)

  • Chang, Seok-Woo;Kwon, Ho-Beom;Yoo, Hyun-Mi;Park, Dong-Sung;Oh, Tae-Seok;Bae, Kwang-Shik
    • Journal of Dental Rehabilitation and Applied Science
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    • v.24 no.1
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    • pp.105-112
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    • 2008
  • The purpose of this study was to evaluate the contact angle made by 3 kinds of self etching primers (Clearfil SE Bond, AdheSE, and Tyrian) on dentin and to measure the microtensile bond strength of resin composite to dentin using these self-etching primers. Contact angle between each of 3 self etching primers and polished dentin surface was measured (n=30) by contact angle analyzer and the result was analyzed by One-way ANOVA. For the measurement of microtensile bond strength, polished dentin surface was treated with each of 3 self etching primers and dentin adhesives. Z-250 composite resin was built-up with a height of 5 mm on the adhesive-treated surface and light cured for 40s with a halogen light curing unit. Thereafter, each tooth was sectioned into slabs perpendicular to the bonded interface and trimmed (n=45). The microtensile bond strength was measured with universal testing machine and the result was analyzed with Kruskal-Wallis test. AdheSE group showed the highest contact angle followed by Clearfil SE group and Tyrian group (p<0.05). AdheSE group and Clearfil SE group showed significantly higher microtensile bond strength than Tyrian group (P<0.05).

Utilization of the Crust from Dry-aged Beef to Enhance Flavor of Beef Patties

  • Park, Bumjin;Yong, Hae In;Choe, Juhui;Jo, Cheorun
    • Food Science of Animal Resources
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    • v.38 no.5
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    • pp.1019-1028
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    • 2018
  • The crust that inevitably forms on dry-aged beef is usually trimmed and discarded before sale. The aim of this study was to explore methods for utilizing this crust in processed meat products. Four sirloins were dry-aged for 28 d at $4^{\circ}C$ (75% relative humidity). The crust obtained from the surface of the sirloins after completion of dry aging was lyophilized. Patties were prepared without added crust (control) or with 5% w/w crust, aerobically packaged, and stored at $4^{\circ}C$ for 7 d. Electronic nose analysis indicated that the volatile profile differed significantly between the patties with and without crust. Compared to the control patties, patties containing crust had higher flavor, tenderness, juiciness, and acceptability scores in a sensory panel evaluation (all p<0.05). In addition, patties with crust were less hard, gummy, and chewy than the control patties after 3 and 7 d of storage (all p<0.05). The number of total aerobic bacteria was higher in raw patties with crust than in the control patties during the storage (p<0.05). However, no pathogens were detected. 2-Thiobarbituric acid reactive substance values of patties containing crust were significantly lower than those of control patties after 2 and 6 d of storage (both p<0.05). Thus, crust from dry-aged beef can enhance the flavor by providing beefy and palatable flavor without a long period of dry aging.

Fabrication of Stable Cartilage Framework for Microtia in Incomplete Synchondrosis

  • Cho, Byung-Chae;Lee, Jung-Hun;Choi, Kang-Young;Yang, Jung-Dug;Chung, Ho-Yun
    • Archives of Plastic Surgery
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    • v.39 no.2
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    • pp.162-165
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    • 2012
  • The synchondrosis between the sixth and seventh costal cartilage is usually used for the base frame in autogenous ear reconstruction. If the synchondrosis is loose, a variety of modifications can be devised. This report introduces new methods for these problems. In cases of incomplete synchondrosis, only the surface of the base block margin was smoothly tapered without carving for the removal of the conchal deepening. The secure fixation of the two segments (helix and antihelix) to the base block using fine wire sutures gave stability to the unstable basal frame. After confirming that all the segments were assembled in one stable piece, the remaining conchal deepening of the basal framework was removed, and the outer lower portion of the basal cartilage was trimmed along its whole length. A total of 10 consecutive patients with microtia, ranging from 8 to 13 years old, were treated from 2008 to 2009. The follow-up period was 6 months to 2 years. Despite incomplete synchondrosis, the stable frameworks were constructed using the authors' method and aesthetically acceptable results were achieved. The proposed method can provide an easy way to make a stable cartilage framework regardless of the variable conditions of synchondrosis.

Muller's Muscle-Levator Aponeurosis Advancement Procedure for Blepharoptosis (뮐러근과 거근건막의 전진술에 의한 안검하수의 교정)

  • Baik, Bong Soo;Kim, Tae Bum;Hong, Wang Kwang;Yang, Wan Suk
    • Archives of Plastic Surgery
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    • v.32 no.2
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    • pp.219-226
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    • 2005
  • Muller's muscle-levator aponeurosis advancement procedure was performed to correct mild to moderate congenital blepharoptosis with moderate to good levator function and to correct severe aquired blepharoptosis with poor levator function. Through the blepharoplasty incision, the upper half of the tarsal plate was exposed and the orbital septum was opened to show the levator aponeurosis. The Muller's muscle was dissected from the superior margin of the tarsal plate and from the posteriorly located conjunctiva with sharp scissors. The Muller's muscle and levator aponeurosis were advanced on the anterior surface of the tarsal plate as a composite flap and fixed approximately 3 to 4 mm inferior to the upper edge of the tarsal plate with three horizontal 6-0 nylon mattress sutures. The amount of advancement of the composite flap was controlled by the location of the upper eyelid margin 2 mm below the upper limbus in primary gaze after the first suture in the middle portion of the flap. The excess flap was trimmed off with scissors, but trimming was usually not necessary in cases of mild to moderate ptosis. Nine cases underwent this Muller's muscle-levator aponeurosis advancement procedure from September 2003 to September 2004. Five cases were congenital blepharoptosis with 2-4 mm ptosis and more than 5 mm of levator function, but three of the four acquired ptosis cases had more than 4 mm ptosis with poor levator function. The age of the patients ranged from 7 to 81 years. In operative results, all patients except one traumatic case were within 1 mm of the desired eyelid height in primary gaze. This procedure can provide not only tightening of the Muller's muscle but also advancement and firm fixation of the levator aponeurosis to the tarsal plate, yielding predictable results.

Deterioration of granite in Bunhwangsaseoktap (Stone pagoda of Bunhwnagsa Temple) (분황사석탑 구성 화강암의 훼손현상)

  • Do, Jinyoung
    • Journal of Conservation Science
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    • v.17 s.17
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    • pp.73-82
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    • 2005
  • The Bunhwangsaseoktop is the oldest stone brick pagoda in Silla Period. The pagoda body is made by piling small brick-shaped stones trimmed from black andesite and the first-story core has a shrine, which is made by granite. In 1915 it was repaired on a large scale, but now is severely damaged. Many kind of the stone decay like flaking, granular disintegration have occurred especially on the granite surface of the pagoda. In this study have been investigated the stone decay type and its cause in relation to efflorescence on the body part. Various analysis show that the deterioration on the granite is due to the same materials that lead to efflorescence on the body stone surface. The soluble salt like sodium nitrate, calcium sulfate and sodium sulfate come from white joint mortar. This salt solution is recrystallized in the outside of the pagoda, but most of them flow down with rain. In This process the porous granite absorbes the dissolved salts with moisture into the inside by capillary action. In order to reduce this problem, therefore, white joint moral is changed with other less soluble materials. And it is necessary to take steps to prevent water from seep into the inside of the stone, because this water dissolves the white joint mortar.

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