• Journal of Power System Engineering
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• v.12 no.1
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• pp.13-19
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• 2008

In this study, a variable induction and exhaust system is applied to turbocharged diesel engine to improve the volumetric efficiency, especially, in a low and transient engine speed range where much of the pollutant matters are expelled out. The volumetric efficiency is known as one of the most important factor which affects significantly engine performance, fuel economy and further emission and noise level. As the torque increase with the engine speed up, the gas flow in an exhaust pipe become pulsating and then has an effect on boost up capacity of air charging into the cylinder and expelling capacity to atmosphere simultaneously. But at a low and idling speed, the pulsation effect was not so significant. Accordingly, resonator was employed to compensate their loss. The variable induction system consists of the secondary pipe, resonator, intercooler, and torque variance were examined with extended operating conditions. In the mean time, for interpretation and well understanding for the phenomena of wave action that arising during intake and exhaust process between turbocharger and variable intake system, the concept of the combined supercharging was introduced. Some of results are depicted which deal with a pressure history during valve events of induction process. Consequently, by the governing of these phase and amplitude of pulsating wave, it enables us to estimate and evaluate for the intake system performance and also, designing stage of the system layout.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.833-837
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• 2010

This study aims at finding an optimal exhaust diffuser design of a high altitude testing chamber for a low bypass turbofan engine (F404-402) with thrust pound force of 17,700 and air mass flow rate of 66kg/s ejecting at a speed of Mach 1.66. The final proposed ejector size has better pressure recovery characteristics and targets to reduce operational cost at engine performance testing. Conventional high altitude test chamber layout was adopted and first drawn in two dimensions using Autocad software so as to determine the gas path, the ejector frontal size was then determined from gas dynamics equations considering traditional gas ejection method where both the engine exhaust and cell cooling air are exhausted via the ejector. Modification to a smaller ejector with an alternative secondary cell cooling exhaust port was then performed and modelled in 3D using Solid Works software.

• Archives of Plastic Surgery
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• v.34 no.4
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• pp.485-489
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• 2007

Purpose: The basic vascular anatomy and versatility of the anterolateral thigh flap was reported firstly by Song in 1984 and then by Zhang who introduced the reverse flow pattern of this flap. In this case, the authors reviewed various articles and their experiences with the distally based anterolateral thigh flap and applied it for coverage of bone-exposed wound occurred at the distal of the disarticulated knee stump. We consequently reported the reliability and resourcefulness of this flap in the difficult and limited situation. Methods: A 67-year-old-man who had suffered from arteriosclerotic obliterans inevitably underwent the disarticulation at knee joint due to clinical deterioration. He presented to our clinic with soft tissue necrosis and bone exposure at the stump. We debrided the wound and conducted the distally based anterolateral thigh island flap by transecting proximal portion of descending branch of the lateral circumflex femoral artery and the $14{\times}10cm$ sized flap was transferred to cover the defect. The pedicle measured 14 cm in length with pivot point 7 cm above the patella. Results: The postoperative course was mainly uneventful except early venous congestion for 4 days and subsequent partial skin loss. The wound was healed by secondary intension and no other sequelae had been observed during follow-up period of 12 months. Conclusion: Despite the presence of various reconstructive choices, the distally based anterolateral thigh island flap can be designed to repair soft tissue defects around the knee region, providing its reliable blood supply and long pedicle length, especially in the challenging cases.

• Journal of the Korean Institute of Gas
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• v.23 no.1
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• pp.54-61
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• 2019

As the market for portable electronic devices expands, the demand for Lithium Ion Battery (LIB) is also increasing. LIB has higher efficiency than other secondary batteries, but there is a risk of explosion / fire due to thermal runaway reaction. Especially, Electric Vehicles (EV) equipped with a large capacity LIB cell also has a danger due to a large amount of toxic gas generated by a fire. Therefore, it is necessary to analyze the risk of toxic gas generated by EV fire to minimize accident damage. In this study, the flow of toxic gas generated by EV fire was numerically analyzed using Computational Fluid Dynamic. Scenarios were established based on literature data and EV data to confirm the effect distance according to time and exposure standard. The purpose of this study is to analyze the risk of toxic gas caused by EV fire and to help minimize the loss of life and property caused by accidents.

• CELLMED
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• v.13 no.14
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• pp.19.1-19.16
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• 2023

Objectives: To compare the efficacy of polyherbal Unani formulations in heavy menstrual bleeding due to endometrial hyperplasia. Methodology: A prospective, randomized comparative trial was conducted at Govt. Nizamia Tibbi College. Group A (n=20) received Itrifal Aftimoon 5g orally BID from menstruation day 3 to day 21 plus suprapubic Marham Dakhilyun application and per vaginally Marham Dakhilyun (5g) and Roghan Gul (10ml) application from menstruation day 5 to day 14. Group B (n=20) received Gulnar Farsi (2g), Phitakri Biryan (0.25g), Dammul Aqwain (0.25g), and Geru (2g), 2.5g powder orally BID, menstruation day 3 for 20 days plus Douche Bargh Sambhalu then Ḥamūl of Safuf Mazu (2g), Kalijiri (2g) and Roghan Gul (10ml) from menstruation day 3 to day 12 for 3 consecutive cycles. The primary outcome was pelvic ultrasound findings of endometrial thickness. The secondary outcome measures were improvement in haemoglobin percentage, change in menstrual flow and menstrual pattern. The level of significance was 5%. Results and conclusion: The intragroup comparison showed that the mean endometrial thickness at baseline and after treatment in groups A and B was extremely significantly different (P<0.0001). The intragroup comparison showed the mean haemoglobin percent at baseline and after treatment in group, A was significantly different (P<0.0001). After treatment, 50% and 60% of participants had normal duration and menstrual blood loss after treatment from baseline in Groups A and B respectively. However, further, phase II and III randomized standard controlled trials in larger samples are recommended to assess the efficacy of these group medicines.

• Journal of Preventive Medicine and Public Health
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• v.29 no.1 s.52
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• pp.43-50
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• 1996

We experienced a case of nephropathy in chronic lead poisoning. The patient was 43-year-old male who has been working in secondary lead smelting plant for 14 years. On admission, blood pressure was 160/90 mmHg and the others were non-specific. In past history, he received chelating agent administration for lead poisoning irregularly and medicated for gout, and the blood lead concentration was $180.0{\mu}g/dl$ on 2 months before admission. Smoking habit has been 1 pack per day for 15 years and drinking habit has been 1 bottle of Soju per day but less flow. In liver function test, AST/ALT were 27/28 IU/l and $\gamma-GT$ was 456 IU/l. In blood test, Hb : 11.5 g/dl, Hct : 34.0% and basophilic stipplings were found in peripheral blood smear. Chest PA was normal and abdominal ultrasonographic finding was non-specific except fatty liver. In the test of lead exposure indices, $PbB:83.0{\mu}g/dl,\;PbU:28.3{\mu}g/l$, and blood ZPP was $300.0{\mu}g/dl$. And in renal function test, BUN : 31.4 mg/dl, blood creatinine : 2.7mg/dl, blood uric acid. 9.1 mg/dl, urinary albumin : 100.0 mg/g creatinine, urinary $\alpha_1-microglobulin$ : 120.5 mg/g creatinine, urinary $\beta_2-microglobulin$ : $183.8{\mu}g/g$ creatinine, and 24 hours urinary creatinine clearance was 31.9 ml/min. The ultrasonoguided renal biopsy showed the global sclerosis of glomerulus, moderate atrophy and loss of tubule, and interstitial fibrosis in light microscopy. There were diffuse losses of brush border of proximal tubule in electronmicroscopy.

• Journal of the Korean Wood Science and Technology
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• v.35 no.1
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• pp.73-80
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• 2007

This study was carried out to separate the heavy toxic metals in eco-building materials by low-temperature pyrolysis, especially arsenic (As) compounds in CCA wood preservative as a solid in char. The pyrolysis was carried out to heat the CCA-treated Hemlock at $280^{\circ}C$, $300^{\circ}C$, $320^{\circ}C$, and $340^{\circ}C$ for 60 mins. Laboratory scale pyrolyzer composed of [preheater$\rightarrow$pyrolyzer$\rightarrow$1st water scrubber$\rightarrow$2nd bubbling flask with 1% $HNO_3$ solution$\rightarrow$vent], and was operated to absorb the volatile metal compound particulates at the primary water scrubber and the secondary nitric acid bubbling flask with cooling condenser of $4^{\circ}C$ under nitrogen stream of 20 mL/min flow rate. And the contents of copper, chromium and arsenic compounds in its pyrolysis such as carbonized CCA treated wood, 1st washing and 2nd washing liquors as well as its raw materials, were determined using ICP-AES. The results are as follows : 1. The yield of char in low-temperature pyrolysis reached about 50 percentage similar to the result of common pyrolytic process. 2. The higher the pyrolytic temperature was, the more the volatiles of CCA, and in particular, the arsenic compounds were to be further more volatile above $320^{\circ}C$, even though the more repetitive and sequential monitorings were necessary. 3. More than 85 percentage of CCA in CCA-treated wood was left in char in such low-temperature pyrolytic condition at $300^{\circ}C$. 4. Washing system for absorption of volatile CCA in this experiment required much more contacting time between volatile gases and water to prevent the loss of CCA compounds, especially the loss of arsenic compound. 5. Therefore, more complete recovery of CCA components in CCA-treated wood required the lower temperature than $320^{\circ}C$, and the longer contacting time of volatile gases and water needed the special washing and recovery system to separate the toxic and volatile arsenic compounds in vent gases.

• International Journal of Computer Science & Network Security
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• v.21 no.12spc
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• pp.664-674
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• 2021

The relevance of this scientific research is determined by the negative impact of the COVID-19 pandemic on the current trends and dynamics of world tourism development. This article aims to identify patterns of development of the modern tourist market, analysis of problems and prospects of development in the context of the COVID-19 pandemic. Materials and methods. General scientific methods and methods of research are used in the work: analysis, synthesis, comparison, analysis of statistical data. The analysis of the viewpoints of foreign and domestic authors on the research of the international tourist market allowed us to substantiate the actual directions of tourism development due to the influence of negative factors connected with the spread of a new coronavirus infection COVID-19. Economic-statistical, abstract-logical, and economic-mathematical methods of research were used during the process of study and data processing. Results. The analysis of the current state of the tourist market by world regions was carried out. It was found that tourism is one of the most affected sectors from COVID-19, as, by the end of 2020, the total number of tourist arrivals in the world decreased by 74% compared to the same period in 2019. The consequence of this decline was a loss of total global tourism revenues by the end of 2020, which equaled $1.3 trillion. 27% of all destinations are completely closed to international tourism. At the end of 2020, the economy of international tourism has shrunk by about 80%. In 2020 the world traveled 98 million fewer people (-83%) relative to the same period last year. Tourism was hit hardest by the pandemic in the Asia-Pacific region, where travel restrictions are as strict as possible. International arrivals in this region fell by 84% (300 million). The Middle East and Africa recorded declines of 75 and 70 percent. Despite a small and short-lived recovery in the summer of 2020, Europe lost 71% of the tourist flow, with the European continent recording the largest drop in absolute terms compared with 2019, 500 million. In North and South America, foreign arrivals declined. It is revealed that a significant decrease in tourist flows leads to a massive loss of jobs, a sharp decline in foreign exchange earnings and taxes, which limits the ability of states to support the tourism industry. Three possible scenarios of exit of the tourist industry from the crisis, reflecting the most probable changes of monthly tourist flows, are considered. The characteristics of respondents from Ukraine, Germany, and the USA and their attitude to travel depending on gender, age, education level, professional status, and monthly income are presented. About 57% of respondents from Ukraine, Poland, and the United States were planning a tourist trip in 2021. Note that people with higher or secondary education were more willing to plan such a trip. The results of the empirical study confirm that interest in domestic tourism has increased significantly in 2021. The regression model of dependence of the number of domestic tourist trips on the example of Ukraine with time tendency (t) and seasonal variations (Turˆt = 7288,498 - 20,58t - 410,88∑5) it forecast for 2020, which allows stabilizing the process of tourist trips after the pandemic to use this model to forecast for any country. Discussion. We should emphasize the seriousness of the COVID-19 pandemic and the fact that many experts and scientists believe in the long-term recovery of the tourism industry. In our opinion, the governments of the countries need to refocus on domestic tourism and deal with infrastructure development, search for new niches, formats, formation of new package deals in new - domestic - segment (new products' development (tourist routes, exhibitions, sightseeing programs, special rehabilitation programs after COVID) -19 in sanatoriums, etc.); creation of individual offers for different target audiences). Conclusions. Thus, the identified trends are associated with a decrease in the number of tourist flows, the negative impact of the pandemic on employment and income from tourism activities. International tourism needs two to four years before it returns to the level of 2019.

• Journal of the Korean Geosynthetics Society
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• v.16 no.4
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• pp.231-240
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• 2017

Recently, there have been frequent occurrences of ground sink in the urban area, which have resulted in human and material damage and are accompanied by economic losses. This is caused by artificial factors such as soil loss, poor compaction, horizontal excavation due to the breakage of the aged sewage pipe, and lack of water proof at vertical excavation. The ground sink can be prevented by preliminary restoration and reinforcement through exploration, but it can be considered that it is not suitable for urgent restoration by the existing method. In this study, a model experiment was carried out to simulate the in-ground cavities caused by groundwater flow for developing non-excavation urgent restoration in underground cavity and the range of the relaxation zone was estimated by detecting the around the cavity using a relaxation zone detector. In addition, disturbance region and relaxation region were separated by injecting gypsum into cavity formed in simulated ground. The shape of the underground cavity due to the groundwater flow was similar to that of the failure mode III formed in the dense relative density ground due to water pipe breakage in the previous study. It was confirmed that the relaxed region detected using the relaxation zone detector is formed in an arch shape in the cavity top. The length ratio of the relaxation region to the disturbance region in the upper part of the cavity center is 2: 1, and it can be distinguished by the difference in the decrease of the shear resistance against the external force. In other words, it was confirmed that the secondary damage should not occur in consideration of the expandability of the material used as the injecting material in the pre-repair and reinforcement, and various ground deformation states will be additionally performed through additional experiments.