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Study on Combustion Performance and Burning Velocity in a Micro Combustor (초소형 연소기에서 연소성능과 연소속도에 대한 연구)

  • Na Hanbee;Lee Dae Hoon;Kwon Sejin
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.29 no.6 s.237
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    • pp.662-670
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    • 2005
  • The effect of heat loss on combustion performance and burning velocity of micro combustors in various conditions were exploited experimentally. Three different gases were used, and various geometric matrixes were considered to figure out the phenomena of combustion in a micro combustor. The micro combustors used in this study were constant volume combustors and had cylindrical shape. Geometric parameter of combustor was defined as combustor height and diameter. The effect of height was exploited parametrically as 1mm, 2mm and 3 mm and the effect of diameter was parameterized to be 7.5 mm and 15 mm. Three different combustibles which were Stoichiometric mixtures of methane and air, hydrogen and air, and mixture of hydrogen and air with fuel stoichiometry of two were used. By pressure measurement and visualization of flame propagation, characteristic of flame propagation was obtained. Flame propagations which were synchronized with pressure change within combustor were analyzed. From the analysis of images obtained during the flame propagations, burning velocity at each location of flame was obtained. About $7\%$ decrease in burning velocity of $CH_4/Air$ stoichiometric mixture compared with previous a empirical result was observed, and we can conclude that it is acceptable to use empirical equations for laminar premixed flame burning velocity to micro combustions. Results presented in this paper will give fine tool for analysis and prediction of combustion process within micro combustors.

Prevalence of Cigarette Smoking and Associated Factors among Male Citizens in Tehran, Iran

  • Kassani, Aziz;Baghbanian, Abdolvahab;Menati, Rostam;Hassanzadeh, Jafar;Asadi-Lari, Mohsen;Menati, Walieh
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.3
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    • pp.1473-1478
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    • 2016
  • Background: Cigarette smoking is as the leading cause of cancer mortality and other chronic diseases in males worldwide. The prevalence of cigarette smoking is different across and within countries by age, education level, occupation, and so on. This study aimed to determine the prevalence of cigarette smoking and its relationship with individuals' demographic factors and BMI in adolescent men living in Tehran, Iran. Materials and Methods: This study involved secondary analysis of the 'Urban Health Equity Assessment and Response Tool-2' survey conducted in Tehran, Iran, among men aged 20+, 2011-2012. Using a multistage sampling method, 45,990 men were included in the study. The cigarette smoking status, BMI and demographic factors measured through a self-administered questionnaire. Chi-square, t-test, and logistic regression model were used to examine the relationships between the independents variables and cigarette smoking behavior, using SPSS software version 21. Results: In the total of 45,990 men, the overall prevalence of cigarette smoking was 14.6% (CI 95%: 14.29-14.94). Age (OR=0.96; CI 95%:0.94-0.98), house ownership (OR=0.68; CI 95%: 0.64-0.72), job status (OR=0.60; CI 95%: 0.46-0.86), marital status (OR=0.42; CI 95%: 0.39-0.47) and educational levels (OR=0.50; CI95%: 0.45-0.54) were associated with the prevalence of cigarette smoking. However, associations with BMI, family size, residency years, and district were not statistically significant. Conclusions: Given the relatively high prevalence of cigarette smoking in the study population, policy interventions are required to address this major public health issue, with a focus on the population demographic influences.

Levels of Depression and Anxiety Post-Mastectomy in Breast Cancer Patients at a Public Sector Hospital in Karachi

  • Khan, Sara;Khan, Naveed Ali;Rehman, Ata Ur;Khan, Iqra;Samo, Khursheed A;Memon, Amjad Siraj
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.3
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    • pp.1337-1340
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    • 2016
  • Background: There is a noticeable change in the approach with which women nowadays seek help for diseases like breast cancer, primarily due to awareness campaigns, but what happens after surgical procedures is of great significance too. This study focused on the several psychological connotations attached to mastectomy and how the patients cope. Objective: To understand the pattern of anxiety and level of depression among Pakistani patients undergoing mastectomy. Materials and Methods: The sample size consisted of 88 patients who had undergone mastectomy at the different surgical units of the Civil Hospital, Karachi, from January 2012-December 2014; The questionnaire was administered before they were discharged i.e. within 3 days of surgical procedures. The patients were asked if they were willing to participate in this study, those who agreed signed the consent form and then we preceded by asking questions with a standardized tool. A self made questionnaire was constructed keeping in mind the nature and specification of the disease, which consisted of 20 questions related to anxiety and depression, focusing on a mixture of psychological and physiological symptoms. Results: There were a total of 88 patients out of which 36 (41%) were aged 51 to 60 years, 24 (27.2%) of the patients were in the age category of 41 to 50 years, 17 aged 61 and above (19.3%) and only 11 (12.5%) 30-40 years of age, the youngest of all the age categories. The pattern of depression and anxiety was found to be similar among all age categories, severe depression and anxiety predominating over moderate level of such symptoms, with only relatively few patients sufering mild or no depression symptoms. Conclusions: It was concluded that going through mastectomy leads to moderate to severe levels of depression and anxiety, primarily because the females feel incomplete and insecure after losing a part of themselves.

Enhancement of Quality Assurance System for Improving the Quality of Suppliers' Product (공급자 부품품질 향상을 위한 품질보증시스템 개선방안)

  • Han, Sung-Jae;Ham, Dong-Han
    • Journal of the Korea Safety Management & Science
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    • v.16 no.3
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    • pp.351-362
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    • 2014
  • A prerequisite for improving the quality of a product is to enhance the quality of its parts supplied from outsourced enterprises. An enterprise certified by ISO 9001 Quality Management System is expected to develop their effective quality assurance system and maintain it through continuous control and improvement, thereby ensuring the good quality of products that they produce. However, it is reported that small and medium-sized enterprises certified by ISO 9001 have difficulty establishing an effective quality assurance system. This study aims to propose a new method of improving a quality assurance system that can be more effective in small and medium-sized enterprises. This study collectively considered requirements specified in several international standards on quality system and the results of expert group brainstorming to identify evaluation areas and items for assessing a quality assurance system. Based on these evaluation areas and items, a set of checklists for diagnosing and improving a quality assurance system was developed. In order to demonstrate the usefulness of the proposed method, this study applied it to ten small and medium-sized enterprises and could identify four approaches for improving their current quality assurance system. The presented improvement method, which consists of establishment of quality goals and quality innovation plan, defective products corrective activities, 4M and design change process, improvement of customer quality information management, is expected to be utilized as a useful tool for the enhancement of the quality assurance system of small and medium-sized enterprises.

Design of the Robust CV Control Chart using Location Parameter (위치모수를 이용한 로버스트 CV 관리도의 설계)

  • Chun, Dong-Jin;Chung, Young-Bae
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.39 no.1
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    • pp.116-122
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    • 2016
  • Recently, the production cycle in manufacturing process has been getting shorter and different types of product have been produced in the same process line. In this case, the control chart using coefficient of variation would be applicable to the process. The theory that random variables are located in the three times distance of the deviation from mean value is applicable to the control chart that monitor the process in the manufacturing line, when the data of process are changed by the type of normal distribution. It is possible to apply to the control chart of coefficient of variation too. ${\bar{x}}$, s estimates that taken in the coefficient of variation have just used all of the data, but the upper control limit, center line and lower control limit have been settled by the effect of abnormal values, so this control chart could be in trouble of detection ability of the assignable value. The purpose of this study was to present the robust control chart than coefficient of variation control chart in the normal process. To perform this research, the location parameter, ${\bar{x_{\alpha}}}$, $s_{\alpha}$ were used. The robust control chart was named Tim-CV control chart. The result of simulation were summarized as follows; First, P values, the probability to get away from control limit, in Trim-CV control chart were larger than CV control chart in the normal process. Second, ARL values, average run length, in Trim-CV control chart were smaller than CV control chart in the normal process. Particularly, the difference of performance of two control charts was so sure when the change of the process was getting to bigger. Therefore, the Trim-CV control chart proposed in this paper would be more efficient tool than CV control chart in small quantity batch production.

Assessment of the Chilling Sensitivity of Korean Rice Cultivars by Chlorophyll Fluorescence Analysis (엽녹소 형광 측정에 의한 수도 내냉성 검정 방법)

  • Rho, Yeong-Deok;Park, Suk-Hong;Park, Rae-Kyeong;J.M. Wilson
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.31 no.3
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    • pp.356-360
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    • 1986
  • The potential of the chlorophyll fluorescence technique in screening eleven rice varieties for chill-sensitivity was assessed by measuring the change in the rate of rise of variable fluorescence (FR) and the maximum yield of variable fluorescence, F$\_$VAR/ (F$\_$MAX/-F$\_$0/) after 8 days chilling at 10$^{\circ}C$. The changes in both fluorescence parameters with chilling agreed well with visual assessments of injury carried out at the end of the chilling period. Furthermore, it was found that in the majority of the rice cultivars tested their chilling sensitivity agreed well with the rate of rise of chlorophyll fluorescence (F$\_$R/) measured at 25$^{\circ}C$. The method of chlorophyll fluorescence was rapid, reproducible, sensitive and non-destructive and it should be a valuable new tool in screening large numbers of closely related rice varieties for chilling sensitivity.

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A Geostatistical Study for the Selection of Prospective Areas of Polymetallic Nodule Deposits (망간단괴광상의 유망광구선정을 위한 지구통계학적 연구)

  • Park, Chan Young;Chon, Hyo Taek;Kang, Jung Keuk
    • Economic and Environmental Geology
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    • v.29 no.5
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    • pp.575-587
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    • 1996
  • The purpose of this study is to develop geostatistical methods for selection of prospective areas of polymetallic nodule deposits in KODOS (Korea Deep Ocean Study) area of the North-East Pacific Ocean. In this study $110{\times}165$ grid system was used, and each node represents the center of an estimated block of $1km{\times}1km$. The ordinary kriging was applied to SeaBeam2000 data in order to evaluate the bathymetry. A structural analysis (variogram) of the bathymetry data was carried out for constructing digital terrain model (DTM) and the maximum slopes of the bathymetry were calculated by DTM data. The above method can be used to solve the problem that is resulted from the lack of theory of a change of support model for the maximum slope of the bathymetry. The ordinary kriging and the indicator kriging were used to evaluate the nodule abundance, and the different two kriging methods were compared to evaluate the accuracy for the estimation of the nodule abundance. It has been shown that indicator kriging was better estimation tool than the ordinary kriging. The overlay map is presented for the selection of potentially minable sites by combining the two indicator maps of the nodule abundance and the maximum slope of bathymetry. This overlay map could be utilized to establish follow-up survey and to investigate the potentially minable sites in the KODOS area.

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A study on early industrial design in America from 1920s to 1930s (미국 산업디자인 정착기 환경에 관한 연구)

  • 신명철
    • Archives of design research
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    • v.15 no.2
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    • pp.243-252
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    • 2002
  • Industrial design has been need to made a new tool for human with adaptable to situation the age. But, at early America, it is very difficult that role of design settle down and progress than these days. It is not to he easy newly born in industrial design because of rapidly changing the America situation with multi settlers, the Depression and world wars. There was various design change in short period. So we called the step modern 1920 and the streamlined 1930. The study is background of American design by variety cultures & creatures from 1920s to 1930s. Some of Korea design has affected of America cultures at duration of 6.25 war and now. This study has included early culture & industrial life, designer activity, and at the part of rear new invention, industrial design relate to architect, four leading designers Walter Dorwin league, Norman Bel Geddes, Henry Dreyfuss, Raymond Loewy. In present world situation, It is important in all aspect to understand that early process at America industrial design. Early American culture is constructed from the building block of the puritan ethic and is sheathed by liberal mercantilism, today is became one stir it into the common molting pot.

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A Scenario based Framework for System Setup and Scheduling in Reconfigurable Manufacturing Systems (재구성형 유연가공라인을 위한 시나리오 기반 시스템 셋업 및 스케줄링 체계)

  • Lee, Dong-Ho;Kim, Ji-Su;Kim, Hyung-Won;Doh, Hyoung-Ho;Yu, Jae-Min;Nam, Sung-Ho
    • Journal of the Korean Society for Precision Engineering
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    • v.28 no.3
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    • pp.339-348
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    • 2011
  • Reconfigurable manufacturing system (RMS), alternatively called changeable manufacturing, is a new manufacturing paradigm designed for rapid change in hardware and software components in order to quickly adjust production capacity and functionality in response to sudden changes in market or in regulatory requirements. Although there has been much progress in hardware components during the last decade, not much work has been done on operational issues of RMS. As one of starting studies on the operational issues, we suggest a framework for the system setup and scheduling problems to cope with the reconfigurability of RMS. System setup, which includes batching, part grouping, and loading, are concerned with the pre-arrangement of parts and tools before the system begins to process, and scheduling is the problem of allocating manufacturing resources over time to perform the operations specified by system setup. The framework consists of 8 scenarios classified by three major factors: order arrival process, part selection process, and tool magazine capacity. Each of the scenarios is explained with its subproblems and their interrelationships.

The Efficacy and Safety of Tetrachlorodecaoxide in Comparison with Super-oxidised Solution in Wound Healing

  • Parikh, Romil;Bakhshi, Girish;Naik, Madhushree;Gaikwad, Bhargav;Jadhav, Kavita;Tayade, Mukund
    • Archives of Plastic Surgery
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    • v.43 no.5
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    • pp.395-401
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    • 2016
  • Background Some of the relatively newer, more efficacious, and potent topical wound dressing solutions include tetrachlorodecaoxide and super-oxidised solution. This study compares the efficacy and safety of these two drugs. Methods This is a block-randomised, double blind, parallel-arm, post-marketing study. One hundred fifty patients with ulcers (75 blocks uniform for sex, ulcer aetiology, diabetes mellitus, and wound area score) were randomised into the two treatment arms. Patients were observed for eight weeks with weekly assessments. One hundred and twenty patients completed the study. Wound healing was objectively assessed by measurement of wound area, scoring of wound exudation and tissue type, and using the pressure ulcer scale of healing Tool (validated for multiple wound aetiologies). Subjective improvement in pain was noted using a visual analogue scale. Both groups were compared using Mann-Whitney U test on all indicators. Results Difference in change in wound tissue type in the two groups was significant (${\alpha}$=0.05) by intention-to-treat (ITT) and per-protocol (PP) analysis at the end of week two (ITT and PP, P<0.001) and week four (ITT, P=0.010; PP, P=0.009). P-values for other comparisons were not significant (P>0.05). No study-related adverse events were observed. Conclusions Both drugs are efficacious. Tetrachlorodecaoxide yields healthy granulation tissue earlier. Both drugs appear to be safe for application.