• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1119-1123
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• 2008

High-frequency induction is an efficient way to heat mold surface by electromagnetic induction in a noncontact procedure. It has been recently applied to the injection molding of thin-walled parts or micro/nano structures. Though the induction heating has an advantage in terms of its rapid-heating capacity on the mold surface, it still has difficulty in efficient mold temperature control due to the restriction of an induction coil design suitable for the given mold shape. The present study proposed a localized mold heating method by means of selective use of mold material. For localized induction heating, an injection mold composed of ferromagnetic material and paramagnetic material is used. The electromagnetic induction concentrates on the ferromagnetic material, from which we can selectively heat for the local mold elements. The feasibility of the proposed heating method is investigated through an experimental measurement in terms of the heating efficiency on the localized mold surface.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 추계학술대회 논문집
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• pp.441-444
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• 2009

Weldlines are generated during the injection molding process when two or more melt flows are brought into contact. At the welded contact region, a 'V'-shaped notch is formed on the surface of the molded part. This 'V'-notch deteriorates not only surface appearance but also mechanical strength of the molded part. To eliminate or reduce weldlines so as to improve the weldline strength, the mold temperature at the corresponding weld locations should be maintained higher than the glass transition temperature of the resin material. The present study implements high-frequency induction heating in order to rapidly raise mold surface temperature without a significant increase in cycle time. This induction heating enables to local mold heating so as to eliminate or reduce weldlines in an injection-molded plastic part. The effect of induction heating conditions on the weldline strength and surface appearance of an injection-molded part is investigated.

• 대한수의학회지
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• 제23권2호
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• pp.179-182
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• 1983

This study was conducted to observe the local irritation histopathologically following the intramuscular injection of iron preparations in guinea pigs. Necropsy findings were edema, hemorrhage and darkish brown pigmentation around the injection sites. On the microscopic examination, the muscle fibers near the injection sites became pale staining or uniformly eosinophilic, indicating necrosis of the fibers, which were occasionally filled with granular bluish-staining material. The nuclei were swollen or pyknotic. Infiltrations of heterophils and macrophages containing iron were evident around the necrotized tissues and the injected iron compounds. Fibrosis was often seen between the affected muscle fibers, and this change was considered as secondary inflammatory process.

• 대한치과마취과학회지
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• 제10권2호
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• pp.172-177
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• 2010

Background: Damages of trigeminal nerve, particularly inferior alveolar nerve and lingual nerve, could occur following dental procedures. In some cases, nerve damage may happen as a complication of the local anesthetic injection itself and not of the surgical procedure. Methods: From September 2006 to August 2010, 5 cases of inferior alveolar nerve and lingual nerve damages, which were assumed to happen solely due to local anesthesia, were reviewed. All cases were referred to Division of Oral and Maxillofacial Surgery, Department of Dentistry, Hanyang University Medical Center for legal authentication in the process of criminal procedure. Results: In all five cases, patients complained of altered sensation occurred in the distribution of the inferior alveolar or lingual nerve following block anesthesia. The local anesthetics were 2% lidocaine with 1 : 100,000 epinephrine and the amount of local anesthetics, which were used during injection, were varied. Most of patients experienced the electric stimulation during injection. Recovery was poor and professional supportive care was mostly absent. Conclusions: Dental practitioners should consider that the surgical procedure caused the trigeminal nerve damage, however, dental local anesthesia for inferior alveolar nerve and lingual nerve could be one of the causes for damages. The various mechanisms for nerve damages by local anesthesia are thoroughly discussed.

• 한국연소학회지
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• 제10권1호
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• pp.1-6
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• 2005

This paper presents the combustion characteristics of hydrocarbon fuel from a conventional pressure-swirl nozzle of a small-scale burner. The nozzle has orifice diameters of 0.256 mm and liquid flow rates ranging from 50 to 64 mL/min were selected for the experiments. The furnace temperature distribution along the axial distance, the gas emission such as CO, $CO_2$, NOx, $SO_2$, flue gas temperature, and combustion efficiency were studied. The local furnace and flue gas temperatures decreased with an increase in air velocity. At injection pressures of 1.1 and 1.3 MPa the maximum furnace temperatures occurred closer to the burner exit, at an axial distance of 242 mm from the diffuser tip. The CO and $CO_2$concentrations decreased with an increase in air velocity, but they increased with an increase in injection pressure. The effect of air velocity on NOx was not clearly seen at low injection pressures, but at injection pressure of 1.3 MPa it decreased with an increase in air velocity. The effect of air velocity on $SO_2$ concentration level is not well understood. The combustion efficiency decreased with an increase in air velocity but it increased with an increase in injection pressure. It is recommended that injection pressure less than 0.9 MPa with air velocity not above 8.0 m/s would be suitable for this burner.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2005년도 동계 학술대회 논문집
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• pp.76-82
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• 2005

This paper presents the combustion characteristics of hydrocarbon fuel from a conventional pressureswirl nozzle of a small-scale burner. The nozzle has orifice diameters of 0.256 mm and liquid flow rates raging from 50 to 64 mL/min were selected for the experiments. The furnace temperature distribution along the axial distance, the gas emission such as CO, $CO_2,\;NOx,\;S0_2,$ flue gas temperature, and combustion efficiency were studied. The local furnace and flue gas temperatures decreased with an increase in air velocity. At injection pressures of 1.1 and 1.3 MPa the maximum furnace temperatures occurred closer to the burner exit, at an axial distance of 242 mm from the diffuser tip. The CO and $CO_2$ concentrations decreased with an increase in air velocity, but they increased with an increase in injection pressure. The effect of air velocity on NOx was not clearly seen at low injection pressures, but at injection pressure of 1.3 MPa it decreased with an increase in air velocity. The effect of air velocity $SO_2$ concentration level is not well understood. The combustion efficiency decreased with an increase in air velocity but it increased with an increase in injection pressure. It is recommended that injection pressure less than 0.9 MPa with air velocity not above 8.0 m/s would be suitable for this burner.

• Journal of Dental Anesthesia and Pain Medicine
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• 제20권3호
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• pp.119-127
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• 2020

This study was conducted to determine how precooling reduces the subjective reported pain and objective pain and to evaluate the effectiveness of precooling the injection site before administration of local anesthesia in children. Electronic databases (PubMed, Ovid SP, Cochrane Central Register of Controlled Trials) were searched for publications from 1980 to 2020. Studies were screened for titles and abstracts, followed by full-text evaluation of included reports. Six studies were included in this systematic review. The primary outcome evaluated was the pain perception or the subjective pain reported by the child receiving the injection. The secondary outcome evaluated was objective pain evaluated in each study. Among 5 studies that evaluated child reported pain scores on a visual analogue scale (VAS), 4 studies reported lower scores in the precooling group and one study reported a higher VAS score in the precooling group than in children treated with 20% benzocaine topical anesthesia. Among 6 studies that evaluated the pain reaction of children by Sound Eye Motor (SEM) score, 4 studies reported a lower SEM score in the precooling group, one study reported no significant difference between the precooling and control groups, and one study reported higher SEM scores in the precooling group than in children treated with 20% benzocaine topical anesthesia. Within the limits of this systematic review, evidence suggests that precooling the injection site with ice can be an effective adjunct to topical anesthesia in reducing both subjective and objective pain during local anesthesia administration in children.

• Advances in pediatric surgery
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• 제4권2호
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• pp.137-143
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• 1998

Intramuscular injection(IM) into the gluteal muscles is a common route of medication, but may lead to complications. A retrospective review of 32 patients who required surgical treatment for local complications of buttock injections in children was made at the Taegu Fatima Hospital during a seven-year nine-month period (March 1990 to December 1997). Local complications included acute inflammation, cellulitis and abscess(71.9 %), and fat necrosis(21.9 %), and injection granuloma(6.2 %). Over the half of injections were on the upper and outer quadrant of the buttock, but the other 43.7 % were in the upper and inner or lower and outer quadrant which are considered unsuitable sites for intramuscular injection. The majority of complications developed within fat tissue(90.6 %) rather than within muscle(9.4 %). Two-thirds of the patients were under 2 years of age, this suggests that it is technically difficult to accurately administer IM injections in small children because muscle mass is smaller compared to subcutaneous. In addition subcutaneous fat is more susceptible to chemical irritation. Staph. aureus was the predominant organism, isolated in 84.6 % of the patients with abscesses. Treatment consisted of needle aspiration, incision and drainage, curettage, or surgical excision. In conclusion, the major factor that contributes to complications following IM of the buttock appears to be the inadvertent intrafat rather than of IM injection. Accurate injection into the muscles based on a knowledge of pelvic anatomy as well as the potential complications is necessary to prevent complications.

• Archives of Plastic Surgery
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• 제37권3호
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• pp.245-249
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• 2010

Purpose: High-pressure injection injury is caused by accidental injection of the high-pressure injection devices in industry. The initial benign appearance of the wound fools patients into delays in an adequate treatment. And it can result in disastrous outcomes such as necrosis and amputation. To avoid the poor prognosis, the injuries require a prompt surgical intervention. The purpose of this article is to recognize the poor outcome of the highpressure injection injury and to introduce an adequate treatment in need. Methods: We have 4 cases of the high-pressure injection injuries in the hand from April, 2005 to March, 2009. Average age is 39 years (30 - 49 years old), 2 cases are the palm of dominant hand, 1 case is the thumb of dominant hand, and 1 case is the palm of non-dominant hand, respectively. We followed up these patients for 20 months on average. In 3 cases, the immediate, aggressive surgical intervention was carried out, but the other one was delayed in early adequate treatment. The wounds were covered by local advancement flap, anterolateral thigh free flap, conservative treatment with antibiotics and dressing. Results: No pathogens after culture were found nor any findings of fracture in imaging study. Conservative treatment, local advancement flap and anterolateral thigh free flap for the open wound resulted in a desirable aesthetic outcome. In a long-term follow up, functional capability of the patient was also satisfactory. Conclusion: Upon initial evaluation, most high-pressure injection injuries present as innocuous wounds with very few symptoms and result in delaying the proper management. And the majority of high-pressure injection injuries will produce significant morbidity to the hand, amputation. And the initial aggressive surgical debridement was needed to prevent the poor outcome. The key to success in treating high-pressure injection injuries of the hand is the prompt aggressive surgical intervention.

• 대한기계학회논문집B
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• 제24권6호
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• pp.870-879
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• 2000

An experimental investigation is conducted to improve a slot film cooling system which can be used for the cooling of gas turbine combustor liner. The tangential slots are constructed of discrete holes with different injection types which are the parallel, vertical, and combined to the slot lip. The investigation is focused on the coolant supply systems of normal-, parallel-, and counter-flow paths to the mainstream direction. A naphthalene sublimation technique has been employed to measure the local heat/mass transfer coefficients in a slot with various injection types and coolant feeding directions. The velocity distributions at the exit of slot lip for the parallel and vertical injection types are fairly uniform with mild periodical patterns with respect to the hole positions. However, the combined injection type increases the nonuniformity of flow distribution with the period equaling twice that of hole-to-hole pitch due to splitting and merging of the ejected flows. The secondary flow at the lip exit has uniform velocity distributions for the parallel and vertical injection types, which are similar to the results of a two-dimensional slot injection. In the results of local heat/mass transfer coefficient, the best cooling performance inside the slot is obtained with the vertical injection type among the three different injection types due to the effect of jet impingement. The lateral distributions of Sh with the parallel- and counter-flow paths are more uniform than the normal flow path. The averaged Sh with the injection holes are $2{\sim}5$ times higher than that of a smooth two-dimensional slot path.