• Title/Summary/Keyword: Forced Injection

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Numerical simulation of turbulent air-flow in a closed engine room with heat source in a ship (열원이 있는 밀폐된 선박 기관실에서의 난류기류에 관한 수치적 연구)

  • 박찬수
    • Journal of Advanced Marine Engineering and Technology
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    • v.22 no.1
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    • pp.100-107
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    • 1998
  • Ventilation of the marine engine room is very important for the health of the workers as well as the nomal operation of machines. To find proper ventilation conditions of this engine room, numerical simulation with standard k-.epsilon. model was carried out. In the present study, the marine engine room is considered as a closed space with a heat source and forced ventilation ducts. The injection angle of air supply is found to be important. Injection with downword angle depresses recirculation flow, causing a strong steam in the wider space of the room. Ventilation and removal of the released heat are promoted with this pattern. There is a possibility of local extreme heating at the upper surface of engine when supply and exhaust ports of air are in bilateral symmetry. The effect of the increase of exhaust port area on ventilation decreases as the number of supply port increases.

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Botox Injection for the Management of Spasmodic Dysphonia (연축성 발성장애(Spasmodic Dysphonia)에 대한 보톡스 주입치료)

  • Choi, Hong-Shik
    • Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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    • v.23 no.2
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    • pp.99-103
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    • 2012
  • Spasmodic dysphonia is a chronic, focal, movement-induced, action-specific dystonia of the laryngeal musculature during speech. It can have a profound effect on quality of life, severely limiting people's communication, especially via telephone and in noisy backgrounds. Spasmodic dysphonia (SD) is usually of the adductor type characterized by glottic contractions causing tightness and voice breaks with forced-strangled voice, but it may also be abductor type or, much less commonly, mixed. Treatment options for adductor spasmodic dysphonia (ADSD) include voice therapy, surgical procedures, and botulinum toxin injections (Botox). The use of Botox injected into the laryngeal muscles remains the "gold standard" treatment for reducing the vocal symptoms of ADSD and Botox induces a temporary paresis of the laryngeal muscles and provides short-term relief of symptoms. Repeated injections of the laryngeal muscles, generally every 3-4 months, are required for continuous relief of symptoms. Improvement in vocal function has been reported after use of Botox injections, though a completely normal voice is rarely achieved. In this hospital, 1,030 patients have been enrolled for Botox injection therapy so far (May, 2012). In this review article, I'd like to present my personal experience of management of spasmodic dysphonia mainly by Botox injection.

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A COMPARISON OF THE ACCESSORY CANAL FILLING EFFECTS OF THE THREE ROOT CANAL FILLING METHODS WITH GUTTA-PERCHA (Gutta-percha를 이용(利用)한 세가지 근관충전법(根管充塡法)의 부근관충전(副根管充塡) 효과비교(效果比較))

  • An, Seong-Ho;Cho, Kyew-Zeung
    • Restorative Dentistry and Endodontics
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    • v.14 no.1
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    • pp.121-133
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    • 1989
  • In order to compare the accessory canal filling effects of the three root canal filling methods with gutta-percha, the author fabricated artificial root canal mold with the first and second accessory canals of chrome-cobalt alloy. After the artificial root canal was filled with gutta-percha by lateral condensation, vertical condensation and low-temperature thermoplasticized gutta-percha injection-molded method, twenty five times respectively, the gutta-percha forced into the first and second accessory canals were measured with caliper for length. The results were as follows: 1. The filling in both accessory canals was most effective in low-temperature thermoplasticized gutta-percha injection-melded method followed in such order as: vertical condensation method and lateral condensation method (p < 0.01). 2. The filling effect of the second accessory canal was more or less higher than that of the first one (p < 0.05). 3. Low-temperature thermoplasticized gutta-percha injection-molded method was fastest in time needed for root canal filling followed by lateral condensation method and vertical condensation method.

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Numerical Simulation of the Effect of Pressure Fluctuation on the Modulation of Equivalence Ratio at the Fuel Injection Hole (압력변동이 연료 분사구에서의 당량비 변동에 미치는 영향에 관한 수치 해석)

  • Kim, Hyeon-Jun;Hong, Jung-Goo;Shin, Hyun-Dong
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.31 no.3 s.258
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    • pp.292-299
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    • 2007
  • In gas turbine technology, the flame stability is inherently greater in conventional diffusion type combustion over a wider range fuel to oxidizer ratio. However, premixed type combustion which has narrow flame stability region, is widely used due to environmental reason. It has been observed in experiments that combustion instability of low frequency (${\sim}10Hz$) results from the modulation of equivalence ratio at fuel injection hole when a pressure fluctuation propagates upwards along the channel of the burner under an unchoked fuel flow condition. In this study, a commercial program was used to determine how the fuel flow rate changed with respect to the pressure, velocity of the fuel flow and the mass fraction in a choked and an unchoked condition. The calculation focuses on the upstream of the dump plane to know how the forced pressure with the fuel injection conditions affects the modulation of the equivalence ratio. Therefore, it is found that pressure fluctuation leads to oscillation of mass flow rate and then results in equivalence ratio modulation under the unchoked fuel flow condition.

Stimulative and Sedative Effects of Essential Oils upon Inhalation in Mice

  • Lim, Won-Churl;Seo, Jeong-Min;Lee, Chun-Il;Pyo, Hyeong-Bae;Lee, Bum-Chun
    • Archives of Pharmacal Research
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    • v.28 no.7
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    • pp.770-774
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    • 2005
  • This study investigated the stimulative or sedative effects of inhaling fragrant essential oils (EOs) by using a forced swimming test (FST) with mice. This behavioral test is commonly used to measure the effects of antidepressant drugs. The inhalation by mice of EOs, such as ginger oil (p<0.05), thyme oil (p<0.05), peppermint oil (p<0.05), and cypress oil (p<0.01) resulted in 5% to 22% reduction of immobility. The same results were achieved when over-agitation was artificially induced in the mice by an intraperitoneal injection of caffeine (a psycho-stimulant). In contrast, inhalation of some EOs by the mice resulted in increased immobility. To evaluate more correctly the sedative effects of EOs, the immobility of over-agitated mice induced with caffeine was ascertained after the inhalation of various EOs. Inhalation of lavender oil (p<0.01) and hyssop oil (p<0.01) increased the immobile state in mice that were treated with caffeine. The results of this study indicate that the inhalation of essential oils may induce stimulative or sedative effects in mice.

Experimental Study on the Anti-depressive Effect of Bee Venom Injection (봉독이 우울증 모델 흰쥐에게 미치는 영향)

  • Lee, Jin-Hee;Kim, Geun-Woo;Koo, Byung-Soo
    • Journal of Oriental Neuropsychiatry
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    • v.21 no.2
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    • pp.61-73
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    • 2010
  • Objectives : The purpose of this study was to assess anti-depressive effects of Bee Venom(BV) on an Animal Model of Depression induced immobility stress. Methods : There was 2 pre-experiments MTT(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and Western blot test and 3 main experiments ; forced swimming test, tail suspension test and Y-maze task. Male rats were used for main experiment. The subject was divided into 4 groups(1. control group injected only saline, without immobility stress 2. Negative group injected saline after 2 hours immobility stress 3. Positive group injected Amitriptyline after 2 hours immobility stress 4. BV group injected Bee Venom after 2 hours immobility stress). Each group consisted of 6 rats. Forced swimming test, tail suspension test, Y-maze task were used to evaluate anti-depressive effect of Bee Venom. Results : In MTT assay, as the density of BV increased, the existence rate of primary neuronal cell increased. In Western blot test, the density of CREB and AKT was increasing as time went by. In forced swimming test, BV group showed immobility decreased more than Normal group and Positive group. In tail suspension test, Normal group and Positive group showed immobility decreased more than BV group. In Y-maze task, BV group showed immobility decreased more than Normal group, but Positive group showed immobility decreased more than BV group. Conclusions : These results suggest that Bee Venom may have anti-depressive effect on depression.

A Study on the Effect of Compression Ratio and EGR on the Partial Premixed Diesel Compressed Ignition Combustion Engine Applied with the Split Injection Method (2단 분사방식을 적용한 부분 예혼합 디젤압축착화연소엔진의 성능에 미치는 압축비 및 EGR의 영향)

  • Chung, Jae-Woo;Kang, Jung-Ho;Lee, Sung-Man;Kang, Woo;Kim, Byoung-Soo
    • Transactions of the Korean Society of Automotive Engineers
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    • v.14 no.5
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    • pp.32-38
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    • 2006
  • Currently, due to the serious world-wide air pollution by substances emitted from vehicles, emission control is enforced more firmly and it is expected that the regulation requirements for emission will become more severe. A new concept combustion technology that can reduce the NOx and PM in relation to combustion is urgently required. Due to such social requirement, technologically advanced countries are making efforts to develop an environment-friendly vehicle engine at the nation-wide level in order to respond to the reinforced emission control. As a core combustion technology among new combustion technologies for the next generation engine, the homogenous charge compression ignition(HCCI) is expanding its application range by adopting multiple combustion mode, catalyst, direct fuel injection and partially premixed combustion. This study used a 2-staged injection method in order to apply the HCCI combustion method without significantly altering engine specifications in the aspect of multiple combustion mode and practicality by referring to the results of studies on the HCCI engine. In addition, this study confirmed the possibility of securing optimum fuel economy emission reduction in the IMEP 8bar range(which could not be achieved with existing partially premixed combustion) through forced charging, exhaust gas recirculation(EGR), compression ratio change and application of DOC catalyst.

A Study on Nitrification and Denitrification in Biofilter & Sulfur- Limestone Single Stream Process (바이오필터와 황-석회석을 이용한 단일흐름 공정에서의 질산화와 탈질 연구)

  • Kim, Tae-Kyu
    • Journal of Environmental Health Sciences
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    • v.32 no.5 s.92
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    • pp.469-477
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    • 2006
  • When denitrification was connected with a single stream process by using biofilter and sulfur-limestone, it was found that such connection enabled highly efficient nitrification without special unit operation of microorganisms or injection of external carbon sources which is being shown in general biological treatment processes. It was observed that in the trickling filter bed, decomposition of organic substances and highly efficient nitrification by both the forced pressure feed trickling and the air fan were simultaneously done. In the denitrification tank where sulfur-limestone was mixed at a certain ratio, limestone was used by autotrophic microorganisms as a source of supply for alkalinity, and nitrate $NO_{3}^{-}$-N was denitrified into nitrogen gas. And in the sulfur-limestone autotrophic denitrification, $NO_{3}^{-}-N\;or\;NO_{2}^{-}-N$ was denitrified as a sulfur compound in reduction state was oxidized into a final output of $SO_{4}^{-2}$. The mean concentration of the discharge water was 8.6 mg/l for T-N and 0.8 mg/l for T-P, respectively, and their mean treatment efficiency was 79.2% and 80.8%, respectively. Implementing highly efficient denitrification without injection of an external organic carbon source or internal return, it is concluded that the proposed process is suitable for a sewerage in a small village with the merits of low power consumption and easy maintenance.

Efficacy of sucrose application in minimizing pain perception related to dental injection in children aged 3 to 9 years: a randomized control trial

  • Ishani Ratnaparkhi;Jasmin Winnier;Divya Shetty;Sanjana R. Kodical;Reema Manoj;Shilpa S Naik
    • Journal of Dental Anesthesia and Pain Medicine
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    • v.24 no.2
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    • pp.109-117
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    • 2024
  • Background: Dental fear and anxiety are significant challenges in managing behavior in children. Oral administration of sucrose or sweet-tasting solutions has shown effectiveness in reducing procedural pain in infants and neonates. This study aimed to investigate whether pre-application of sucrose solution had an effect on minimizing pain perception during injection and to assess the potential impact of the child's age and sweet preference. Methods: A randomized control clinical trial was conducted on 60 children aged 3-9 years requiring buccal infiltration injections. Following parental consent, demographic data of the children were recorded. Sweet preferences was assessed using a modified forced-choice test. Children were equally and randomly allocated into study (sucrose) and control groups using a lottery method. Sucrose solution or distilled water, respectively, was applied to the lateral surface of the tongue for 2 min. Topical anesthetic was applied at the site of injection, followed by local anesthesia administration. The children rinsed their mouths thrice with water immediately after anesthetic injection. A video was recorded during injection which was then scored by three blinded examiners on the Sound Eye Motor (SEM) scale. The children also self-evaluated using Wong-Baker Faces Pain Rating Scale (WBFPS). Results: The mean SEM scores and WBFPS scores were analyzed using the Kruskall-Wallis test. The mean SEM score in the study group was 1.37 ± 0.61, compared to 3.17 ± 0.87 in the control group, showing a statistically significant difference (P < 0.001). Mean pain scores assessed by WBFPS in the study group were 0.60 ± 1.4, while in the control group, they were 6.27 ± 2.33, also showing a statistically significant difference (P < 0.001). Children with a sweet preference demonstrated a subjective reduction in pain perception. Conclusion: Application of sucrose before dental injections in children helps to minimize pain upon injection across all age groups.

A Heuristic Approach for an Layout and Sizing of an Ejector Pin (사출 금형의 밀핀 설계를 위한 경험적 설계 접근법)

  • 이희성;변철웅;이수홍
    • Korean Journal of Computational Design and Engineering
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    • v.9 no.2
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    • pp.112-121
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    • 2004
  • As customers demands are rapidly changing, a product life cycle is getting shorter and a product model is forced to be changed frequently. An ejecting design system becomes more important for high productivity to eject a product in high temperature without any damage. For example, an ejector pin that is a key component of the system can cause high local stresses and strains in the molding at the time of ejection. The number, the size, and the location of pins are important to make a smooth ejection. Therefore we propose an analytical approach with the aid of designer’s experience to calculate a total release force and pressure distribution so that the number, the size, and the location of pins can be easily determined. As a part of the result, the design system is built by Intent! with AutoCAD 2000 and a video player deck example is presented to verify the approach.