• International Journal of Advanced Culture Technology
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• 제10권2호
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• pp.187-193
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• 2022

We is configured the honk changing-status technique that is to meld the square-built blow-shock status of the gleam-differential perception level (BIAL) on the honk perception lineament. The perception level condition by the honk perception lineament system is constituted with the blow-shock system. As to experimentation a ductile-dot of the gleam ductile-dot, we are found of the honk value with ductile-dot by the blow upper shift. The concept of perception level is constituted the reference of gleam-differential level for changing-status signal by the honk shock lineament. Further symbolizing a square-built changing-status of the BIAL, of the average in terms of the blow-shock lineament, and the honk ductile-dot shock that was the honk value of the far changing-status of the Ho-PL-FA-θ_AVG with 15.41±8.63 units, that was the honk value of the convenient changing-status of the Ho-PL-CO-θ_AVG with 8.70±3.06 units, that was the honk value of the flank changing-status of the Ho-PL-HO-θ_AVG with 2.65±1.19 units, that was the honk value of the edge changing-status of the Ho-PL-VI-θ_AVG with 0.51±0.18 units. The blow shock will be to investigate at the square-built ability of the blow-shock lineament with ductile-dot by the honk perception level on the BIAL, that is denote the gleam-differential lineament by the perception level system. We will be possible to curb of a lineament by the differential signal and to employ the honk data of blow shock level by the blow perception system.

• Elastomers and Composites
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• 제57권4호
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• pp.138-146
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• 2022

Research on the reduction of plastic use to prevent environmental pollution is urgently needed. Accordingly, studies on reducing the weight of polyethylene terephthalate (PET) bottles are currently being conducted. PET bottles are fabricated by injection stretch blow molding. In this study, stretch blow molding for fabricating PET bottles using preform studied through a computer simulation. Blowing characteristics are analyzed by varying the start time of the pre-blow, which is one of the process conditions of stretch blow molding. Simulation results and the preform inflation process are presented, and the parameters of stretch ratio, stretching path, thickness distribution, and weight distribution of blown PET bottles are investigated.

• 소성∙가공
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• 제14권3호
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• pp.233-238
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• 2005

Blow molding is divided into three categories, injection stretch blow molding, injection blow molding, and extrusion or direct blow molding. Extrusion blow molding has been studied experimentally to characterize the blowing behavior of parison. Blow conditions such as blowing temperature and cooling time were the experimental variables in this blowing experiment. Wall thickness of the lower part of blow molded sample was thicker than that of the upper part because of the sagging of parison during extrusion process. As temperature increases the wall thickness and the weight of blow molded sample decreased. No thickness variations in the blowing sample were observed according to the cooling time. The lower part of the sample showed high degree of crystallinity compare with the upper part of the sample. Thus the lower part of the sample was strong mechanically and structurally. It was recognized that the uniform wall thickness could not be obtained by only controlling the operational conditions. Parison variator should be introduced to get uniform wall thickness of parison and subsequently produce uniform wall thickness of blow molded product.

• Geomechanics and Engineering
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• 제37권4호
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• pp.323-339
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• 2024

If the pressure exerted on the face of a tunnel excavated by TBM exceeds a threshold, it leads to failure of the soil or rock masses ahead of the tunnel face, which results in heaving the ground surface. In the current research, the upper bound method of limit analysis was employed to calculate the blow-out pressure of tunnels excavated in rock masses obeying the Hoek-Brown nonlinear criterion. The results of the proposed method were compared with three-dimensional finite element models, as well as the available methods in the literature. The results show that when σ_ci, m_i, and GSI increase, the blow-out pressure increases as well. By doubling the tunnel diameter, the blow-out pressure reduces up to 54.6%. Also, by doubling the height of the tunnel cover and the surcharge pressure exerted on the ground surface above the tunnel, the blow-out pressure increased up to 74.9% and 5.4%, respectively. With 35% increase in the unit weight of the rock mass surrounding the tunnel, the blow-out pressure increases in the range of 14.8% to 19.6%. The results of the present study were provided in simple design graphs that can easily be used in practical applications in order to obtain the blow-out pressure.

• Design & Manufacturing
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• 제14권4호
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• pp.52-57
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• 2020

In this study attempted to prevent defects due to blow holes among defects of sand casting products. It was intended to reduce the defect rate by reducing the blow hole of the inner surface. Currently, expectations and requirements for the quality level of non-ferrous aluminum casting in the casting industry are increasing. In addition, the shape is complex and the shrinkage precision is required. Among them, the test prototype is expensive to manufacture the mold, and the production time is also long, and the product is manufactured by sand casting. At this time, the highest defect rates are defects caused by shrinkage defects, surface defects, and blow holes.. At this study, the manufacturing time was shortened by using the shape of the fluid movement path in advance. Also, it is possible to reduce defects due to blow holes.

• 대한기계학회논문집B
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• 제27권8호
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• pp.1089-1096
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• 2003

An experiment was performed to investigate lift-off, blow-off and combustion characteristics of a lifted coaxial diffusion flame according to fuel jet and air velocity. A jet diffusion flame which is attached on the nozzle rim begins to be lifted with increase of air velocity, and finally becomes blow-off at higher air velocity. In experiment, blow-off limit increased with increase of fuel jet velocity, however lift-off occurred at lower air velocity. Flame structure and combustion characteristics were examined by schlieren photos, temperature distributions and emission concentration distributions. Flame temperature became higher at midstream and its RMS became larger at up and downstream with increase of air velocity. Local NO concentration decreased but $CO_2$concentration increased with increase of air velocity, which shows combustion reaction becomes close to be stoichiometric at higher air velocity in spite of lift-off.

• Archives of Plastic Surgery
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• 제35권5호
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• pp.560-564
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• 2008

Purpose: Because of traffic accidents and many criminal violences, the incidence of facial trauma has been increasing not only in adults but also in children. We planed this study to introduce our experience about pediatric blow out fracture and provide more information. Methods: We made retrospective study in 76 children with blow out fracture from January 2001 to September 2005 by retrospective chart review including detailed preoperative and postoperative evaluations, age, sex, cause, symptom and sign, and their post-operative complications. Results: Among our patients, 69 were male and 7 were female. The ages ranged from 7 to 18 years, which shows the greatest incidence of blow out fracture. Physical violence(46%) was the most common cause in this group and was followed by vehicle accident(28%), and fall down accident(17%). Left side(64%) showed slightly more incidence than right side(36%), but there were no statistical importance. Ecchymosis(88%) was the most common symptom and followed by periorbital swelling(68%) and diplopia(30%). 30 patients was diagnosed with another facial bone fracture and nasal bone(51%) was the most common associated facial bone fracture. Fourty four Patients(60%) got an orbital wall reconstruction in 7 days after trauma. After the operation, only 3 patients(4%) suffered from diplopia postoperative 3 month, and resolved in 4 years. Conclusion: The incidence of blow out fracture in children has been increasing every year, and violence has become more important etiology of pediatric blow out fracture and public and private education institutions were the most common place that blow out fracture originated. Accurate diagnosis and careful treatment plans are important in pediatric blow out fracture.

• Design & Manufacturing
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• 제2권3호
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• pp.22-27
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• 2008

Forming of PET bottle was performed by injection-stretch blow molding. Blow molding is process of contacting the dies with air of materials by pressing. In this paper, the aim was to improve reliability of technical stabilization for the PET bottle that is last productive product and process technology which was able to do maximization by a preform performance enhancement of the uniform thickness that took temperature and a characteristic of materials. Preform design and dies manufacture were conducted using injection blow molding analysis results. Therefore thickness error of 5% for PET bottle can be obtained in this paper.

• 한국연소학회지
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• 제17권4호
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• pp.11-20
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• 2012

The Blow-off characteristics of LPG/air lean pre-mixed flames were experimentally investigated using a double and a multiple concentric coflow burners. Experiments were conducted to understand the effects of recirculation motion, thermal interaction between flames, and stratified flame configuration. Here, the stratified premixed flame is a "new concept" of a flame that sequentially contains fuel rich, stoichiometric, and fuel lean reaction zones in a flame. The blow-off from a lean premixed flame was significantly suppressed with recirculation motion. The recirculation motion by itself, however, was not sufficient to prevent the blow-off when the equivalence ratio became low. The existence of a inner premixed flame could also help to prevent the blow-off of lean premixed flame; however, the blow-off suppression effect was rather diminished by weakened recirculation motion with the presence of inner flame. The inner flame could be separated from an outer flame on a multiple concentric coflow burner, causing recirculation motion as well as thermal interaction between flames to become effective; therefore, the blow-off was further suppressed. The lean premixed flame could be stabilized with a fuel rich premixed flames that was produced with the supply of fuel through an inner nozzle. The penetration of lean premixed gas from outside into the fuel stream produced a lifted rich premixed flame. Chemiluminescence images of OH, CH, and $C_2$ radicals confirmed the structure of a stratified premixed flame. The stable premixed flames could be obtained at the very fuel lean condition by applying the stratified premixed flame concept.

• Kyungpook Mathematical Journal
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• 제61권1호
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• pp.1-10
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• 2021

This paper is concerned the finite time blow-up of solution for higher-order nonlinear Kirchhoff-type equation with a degenerate term and a source term. By an appropriate Lyapunov inequality, we prove the finite time blow-up of solution for equation (1.1) as a suitable conditions and the initial data satisfying ||Dmu0|| > B-(p+2)/(p-2q), E(0) < E1.