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Recent Progress in Air-Conditioning and Refrigeration Research: A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2008 (설비공학 분야의 최근 연구 동향: 2008년 학회지 논문에 대한 종합적 고찰)

  • Han, Hwa-Taik;Choi, Chang-Ho;Lee, Dae-Young;Kim, Seo-Young;Kwon, Yong-Il;Choi, Jong-Min
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.21 no.12
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    • pp.715-732
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    • 2009
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2008. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) Research trends in thermal and fluid engineering have been surveyed in the categories of general fluid flow, fluid machinery and piping, new and renewable energy, and fire. Well-developed CFD technologies were widely applied in developing facilities and their systems. New research topics include fire, fuel cell, and solar energy. Research was mainly focused on flow distribution and optimization in the fields of fluid machinery and piping. Topics related to the development of fans and compressors had been popular, but were no longer investigated widely. Research papers on micro heat exchangers using nanofluids and micro pumps were also not presented during this period. There were some studies on thermal reliability and performance in the fields of new and renewable energy. Numerical simulations of smoke ventilation and the spread of fire were the main topics in the field of fire. (2) Research works on heat transfer presented in 2008 have been reviewed in the categories of heat transfer characteristics, industrial heat exchangers, and ground heat exchangers. Research on heat transfer characteristics included thermal transport in cryogenic vessels, dish solar collectors, radiative thermal reflectors, variable conductance heat pipes, and flow condensation and evaporation of refrigerants. In the area of industrial heat exchangers, examined are research on micro-channel plate heat exchangers, liquid cooled cold plates, fin-tube heat exchangers, and frost behavior of heat exchanger fins. Measurements on ground thermal conductivity and on the thermal diffusion characteristics of ground heat exchangers were reported. (3) In the field of refrigeration, many studies were presented on simultaneous heating and cooling heat pump systems. Switching between various operation modes and optimizing the refrigerant charge were considered in this research. Studies of heat pump systems using unutilized energy sources such as sewage water and river water were reported. Evaporative cooling was studied both theoretically and experimentally as a potential alternative to the conventional methods. (4) Research papers on building facilities have been reviewed and divided into studies on heat and cold sources, air conditioning and air cleaning, ventilation, automatic control of heat sources with piping systems, and sound reduction in hydraulic turbine dynamo rooms. In particular, considered were efficient and effective uses of energy resulting in reduced environmental pollution and operating costs. (5) In the field of building environments, many studies focused on health and comfort. Ventilation. system performance was considered to be important in improving indoor air conditions. Due to high oil prices, various tests were planned to examine building energy consumption and to cut life cycle costs.

Experimental Study on the Thermodynamic Characteristics of Commercial Small-size Moxa Combustion (상용 소형 쑥뜸의 열역학적 특성에 대한 실험적 연구)

  • Lee Geon-Mok;Hwang Yoo-Jin;Lee Gun-Hyee
    • Journal of Acupuncture Research
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    • v.18 no.6
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    • pp.171-187
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    • 2001
  • Objective : Moxibustion has been proved efficacious for many diseases, but isn't widespread in the clinics due to a danger of skin burning, the smoke produced while burning a moxa combustion and so on. Therefore, another type of moxa that can be resolved these troubles is required. To improve the effect of moxibustion and develop the new thermal stimulating treatment, the performance of commercial moxibustion widely used are studied systematically and found out quantitatively. Methods : We have selected two types (small-size moxa A(sMA), small-size moxa B (sMB)) among small-size moxaes used widely in the clinic. We examined combustion time, various temperatures, temperature gradient in each period during a combustion of moxa. Results : 1. The combustion time in the preheating period appeared somewhat longer in sMA than in sMB. 2, The combustion time in the heating period appeared longer in sMA by 26% than in sMB. 3. The average temperature in the heating period was $37.6{\sim}37.8^{\circ}C\;in\;sMA\;and\;36.2{\sim}36.8^{\circ}C$ in sMB and the maximum temperature measured at a center of contact surface in sMA was $48.6^{\circ}C$, higher by over $2.8^{\circ}C$ than that of sMB moxibustion. 4. The average ascending temperature gradient in the heating period was $0.08{\sim}0.1^{\circ}C/sec$ in both moxaes, and the average ascending temperature gradient of heating period in sMB appeared larger. The maximum ascending temperature gradient appeared higher in sMB, and the time reaching maximum ascending temperature gradient appeared much earlier in sMA than in sMB. 5. The combustion time in the retaining period was around 100 sec in sMA and around 275 sec in sMB. 6. The average temperature in the retaining period was $42.2{\sim}46.0^{\circ}C\;in\;sMA\;and\;39.3{\sim}41.4^{\circ}C/sec$ in sMB. The minimum temperature in the retaining period was over $38.80^{\circ}C$ in sMA but just $34.7^{\circ}C$ in sMB. 7. The average descending temperature gradient in sMA was $-0.050{\sim}0.067^{\circ}C/sec$ and in sMB was $-0.030{\sim}0.037^{\circ}C/sec$ 8. The combustion time in the cooling period appeared longer over two times in sMA than in sMB, and the time which the cooling period (minimum temperature) finished at appeared later in sMB by 55 sec. 9. We classified the combustion process that the measured temperature rose over body heat($37^{\circ}C$) into the effective combustion period. The effective combustion time was 233.3 sec in sMA and 300.4 sec in sMB respectively, and was longer by about 29% in sMB. The average temperature and maximum temperature in the effective combustion time appeared higher in sMA. The time taken until the maximum temperature was reached was 225.1 sec in sMA and 244.5 sec in sMB, faster by about 20 sec in sMA. The maximum ascending temperature gradient during the effective combustion period appeared larger about 1.4 times in sMB, but the time when the maximum ascending temperature gradient happened was faster in sMA. Conclusion : It appears that sMB, compared with sMA, is proper if necessary to apply the long time and weak stimulus, because of the gentle stimulus during the relatively longer time. In contrast, sMA that the symmetrical combustion happened is proper if necessary to apply the short time and strong stimulus.

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Gender Differences of Susceptibility to Lung Cancer According to Smoking Habits (흡연습관에 따른 폐암발생 감수성에 대한 성별의 차이)

  • Choi, Chung-Kyoung;Shin, Kyeong-Cheol;Lee, Kwan-Ho
    • Tuberculosis and Respiratory Diseases
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    • v.49 no.5
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    • pp.576-584
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    • 2000
  • Background : With the increase of cigarette consumption by women and the young, the incidence of lung cancer is expected to increase during the next three or four decades in Korea. The purpose of this study was to analyze the smoking habits in patients with lung cancer and to identify the gender differences in terms of their susceptibility to cigarette related carcinogens. Method : This investigation was a hospital-based case control study, which included the data of 178 case subjects (72 females, 106 males) with lung cancer and 218 control subjects (97 females, 121 males) with diseases unrelated to smoking. The information was obtained through a direct personal interview and a questionnaire related to personal smoking history. Results : The relative frequency of the squamous cell carcinoma was substantially higher in males than in females (61.3% in males, and 29.2% in females), while adenocarcinoma including bronchoalveolar cell carcinoma was higher in females(31.9% in females, 18.9% in males). Kreyberg I lung cancer was of relatively higher frequencies in males and smokers, while Kreyberg II lung cancer was higher in females and never smokers. The odds ratios (ORs) at each exposure level were consistently higher in females than males. For all cell types, the risk of lung cancer was increased with the quantity of smoked cigarettes, duration of smoking, and depth of inhalation. Odds ratio was distinctly higher in Kreyberg I lung cancer than in total lung cancer and a steeper gradient of risk with increased smoking was observed in females. Conclusion : The relative risk for lung cancer was consistently higher in females than in males at every level of exposure to cigarette smoke. This is believed to be due to the higher susceptibility of females to tobacco carcinogens, such as gender associated differences of carcinogen activation and/or the elimination of smoking related metabolites.

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A Study on the State of Smoking and Smoking-Related Oral Health Knowledge Level among Some Adolescents (일부 청소년의 흡연 실태와 흡연 관련 구강건강지식수준에 관한 연구)

  • Lee, Hyun-Ok;Chun, Ju-Yeon;Ju, On-Ju
    • Journal of dental hygiene science
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    • v.11 no.6
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    • pp.535-542
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    • 2011
  • The purpose of this study was to examine the state of smoking among adolescents and their smoking-related oral health knowledge. The subjects in this study were the teens who were selected by convenience sampling from among the students who were in their first, second and third years in four different middle schools in the city of Iksan, North Jeolla Province. A self-administered survey was conducted from June 14 to July 12, 2011, and the answer sheets from 1,219 respondents were selected for analysis. The collected data were analyzed by the statistical package 12.0, and the findings of the study were as follows: 1. The smoker students accounted for 10.6 percent. The boys and girls who smoked respectively represented 16.0 and 5.4 percent. 2. As for the period of smoking, the largest group that accounted for 51.6 percent smoked for less than a year. Concerning the amount of daily smoking, the greatest group that accounted for 91.9 percent smoked less than 10 cigarettes. As to the motivation of smoking, the biggest group that represented 52.8 percent started to smoke out of curiosity. 3. Regarding smoking-related oral health knowledge, they got a mean of 0.85. Their scores in knowledge of oral malodor(0.95), oral cavity cancer(0.94) and periodontal diseases(0.93) were above the average, and their scores in knowledge of dental caries(0.70) and blunting of taste(0.77) were below the average. 4. The seventh graders got the best score of 5.28 in smoking-related oral health knowledge(p<0.01), and the students who were more satisfied with their life had a better oral health knowledge(p<0.05). 5. The senior students were more dependent on nicotine(p<0.01), and the number of smoking days(${\beta}=0.407$, p<0.001) and the period of smoking(${\beta}=0.235$, p<0.01) affected their nicotine dependence.

A study on the location of fire fighting appliances in cargo ships (화물선 소화설비 비치에 대한 연구)

  • Ha, Weon-Jae
    • Journal of Advanced Marine Engineering and Technology
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    • v.40 no.9
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    • pp.852-858
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    • 2016
  • To safeguard the accommodation spaces on cargo ships from fire, structural fire protection provisions introduced by SOLAS and these measures retard the propagation of flames and smoke. SOLAS also specifies provisions for fire fighting drills. These provisions are a combination of regulations regarding structure and equipment and those dealing with the human element for the fire protection and effective responses in the event of fire. Requirements related to the human element play a supporting role to the requirements for structure and equipment because the present accommodation structure and equipment are insufficient for extinguishing a fire, therefore, fire-extinguishing activity performed by crew members is essential. To reduce human error and ensure effective fire fighting, it is necessary to install a fire-fighting system and improve the fire fighting process. The fundamental concept of fire fighting exercises is to commence fire fighting before the fire grows too big to extinguish. It is essential to relocate the storage place of fire fighting equipment to expedite the fire-fighting exercise. This study was carried out to reduce human risk for this purpose, the fire control station was relocated to a site that could be accessed from the open deck. Further, two sets of a fire fighter's outfit were stored at the same site. This relocation eliminated the risk of the crew reentering to operate the fire fighting system in the fire control station and allowed the crew to pick up the fire fighters' outfits quickly in the event of a fire. In addition, it was proposed that the IIC method be made mandatory. This method is combination of automatic fire detection system and sprinkler system which can reduce the risk of the fire fighting exercises for the crew and to suppress fire in the initial stage. This study was carried out to provide a foundation to the possible amendment of the relevant SOLAS regulations and national legislation.

Environmental Tobacco Smoking, Parental Allergy History and Pediatric Asthma and Wheezing (부모에 의한 간접흡연 및 부모의 알레르기성 질환력과 소아 천식과의 관계에 관한 연구)

  • Lee, Keun-Bok;Lee, Weon-Yong
    • Journal of agricultural medicine and community health
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    • v.34 no.2
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    • pp.175-187
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    • 2009
  • Objectives: This study was conducted to investigate whether joint effects between family allergy history and environmental tobacco smoke(ETS) by parents were associated with pediatric asthma and wheezing. Methods: The study objects of this study were 2301 element school students and their parents in an urban-rural areas of Gyeonggi-do. Pediatric asthma and wheezing were identified by measures of International Study of Asthma and Allergies in Childhood (ISAAC) questionnaires. We investigated history of parental allergy, ETS, and other socioeconomic status of both parent. Data were analyzed using logistic regression methods. Results: After adjusting other variables, children with maternal asthma history were more likely to be reported life time wheezing (OR: 3.79 95%CI:2.43-5.90), recent wheezing (OR:4.09 95%CI:2.28-7.38), and diagnostic asthma (OR:2.61 95%CI: 1.44-4.75). Paternal asthma history increasing risk of life time wheezing (OR 2.01 95%CI:1.19-3.38) and recent wheezing (OR:2.38 95%CI:1.24-4.56). Joint effect between parental allergy history and ETS significantly effected on child's life time wheezing and recent wheezing. The risks of life time wheezing (OR:2.47 95%CI:1.64-3.717) and recent wheezing (OR: 2.51 95%CI:1.34-4.69) were significantly higher than others without both factors. The risk of recent wheezing of children with maternal recent smoking and parental allergy history (OR:4.83 95%CI:1.89-12.33) was higher than their counterpart. Conclusions: The result of this study implies that children with family allergy history and passive smoking are more likely to be get asthma and wheezing than children with family allergy history and non-passive smoking. This study provide the object information to increase the efficiency of non-smoking campaign and education for decreasing pediatric asthma risk.

Microsatellite Instability in Non-Small Cell Lung Cancer (비소세포폐암에서 Microsatellite Instability)

  • Jeon, Hyo-Sung;Kim, Jeong-Ran;Son, Ji-Woong;Park, Sun-Ha;Park, Tae-In;Kim, Chang-Ho;Kim, In-San;Jung, Tae-Hoon;Park, Jae-Yong
    • Tuberculosis and Respiratory Diseases
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    • v.48 no.1
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    • pp.24-32
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    • 2000
  • Purpose: Microsatellite instability(MSI) is frequently used as an indicator of microsatellite mutator phenotype(MMP) tumors. MSI has been observed in a percentage of non-small cell lung cancer(NSCLC). However, its role in tumorigenesis of NSCLC remains unknown. The frequency and pattern of MSI in NSCLC were evaluated and clinical parameters of MSI-positive tumors with those of MSS(microsatellite stable) tumors were compared. Materials and Methods: Twenty surgically resected NSCLCs were analyzed for 15 microsatellite markers located at chromosomes 3p and 9p. The peripheral blood lymphocytes of patients were used as the source of the normal DNA. Results: 1) Of 20 cases, 8(40%) demonstrated MSI. 2) Instability was observed more frequently in tri- and tetra-nucleotide repeats than in dinucleotide repeats. In all cases, instability appeared as a shift of individual allelic bands. 3) LDH was observed in 10(50%) of 20 tumors analyzed. 4) Of 20 cases, MSI-H tumor(showing MSI in the majority of markers) was absent. There were 5 MSI-L tumors(showing MSI in a greater than 10% of markers). 5) No significant difference was observed between MSI-L tumors and MSI-negative tumors in terms of clinicopathologic features such as pack-year history of smoking, histologic subtype, and(delete) stage of disease. There was also no significant difference in the incidence of LDH in relation to the status of MSI. Conclusion: These data strongly suggest that MSI plays different roles in lung and colon cancer. MMP pathway appears to be far less important in the tumorigenesis of NSCLC, caused mainly by cigarette smoke, with little familial tendency.

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The Difference of Lung Cancer Prevalence According to Smoking Habits (흡연 습관에 따른 폐암 발생의 차이)

  • Park, Moo Suk;Chung, Jae Ho;Jung, Jae Hee;Kim, Young Sam;Kim, Se Kyu;Jee, Sun Ha;Chang, Joon;Kim, Sung Kyu
    • Tuberculosis and Respiratory Diseases
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    • v.55 no.3
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    • pp.267-279
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    • 2003
  • Background : The purpose of this study was to analyze the smoking habits in patients with lung cancer and identify any difference of prevalence according to histologic types of lung cancer. Methods : The data were calculated by total amounts of tar and nicotine inhaled during the whole lifetime according to variation of smoking habit. This study was to investigated any difference of prevalence in lung cancer according to smoking habits. The subjects comprised 150 lung cancer cases and 300 hospital control cases that were matched by age and sex. Smoking habits during the whole lifetime were surveyed by standardized questionnaire. Odds ratios were estimated by unconditional logistic regression analysis. Results : There were 104 male and 34 female lung cancer cases. By histologic type, there were 53 cases of squamous cell carcinoma, 67 of adenocarcinoma and 30 of small cell lung carcinoma. The differences between lung cancer cases and controls according to smoking habits were total duration of smoking, total pack years of smoking and number of cigarettes smoked per day during the previous two years. The odds ratio were higher in Kreyberg I, but not in Kreyberg II, for the longer duration of smoking, the greater total pack years of cigarettes consumed, the more cigarettes smoked per day during the previous two years, the longer duration on non-filter smoking, the earlier life cases who began to smoke, and the higher amounts of calculated total tar and nicotine inhaled over the whole lifetime. When we added grade of inhalation to calculation of amounts of tar and nicotine inhaled over the lifetime, the odds ratios of total inhalation amounts of tar and nicotine were as high as those the without them. Conclusions : This study reconfirmed that smoking habits were strongly associated with lung cancer and that there were different associations between smoking habits and histologic types of lung cancer. In particular, calculations of total tar and nicotine amounts inhaled over the whole lifetime were calculated for the first time in trials from lung cancer epidemiologic studies.

Alteration of Coagulation and Fibrinolysis System According to Right Ventricular Dysfunction in Chronic Obstructive Pulmonary Disease (만성폐쇄성폐질환에서 우심실 기능 부전에 따른 혈액응고 및 섬유소용해계 변화)

  • Kim, Young;Jang, Yoon Soo;Kim, Hyung Jung;Kim, Se Kyu;Chang, Joon;Ahn, Chul Min;Kim, Sung Kyu;Kwak, Jin Young;Choi, Jin Hwa
    • Tuberculosis and Respiratory Diseases
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    • v.60 no.6
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    • pp.625-630
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    • 2006
  • Background: Pulmonary hypertension in COPD patients is the result of a direct effect of tobacco smoke on the intrapulmonary vessels with the abnormal production of the mediators that control vasoconstriction, vasodilatation, and vascular cell proliferation, which ultimately lead to aberrant vascular remodeling and physiology. COPD patients are prone to the developmint of an acute and chronic thromboembolism with an elevation of the plasma procoagulant and fibrinolytic markers However, the roles of the coagulation and fibrinolysis system on the right ventricular dysfunction in COPD patients are not well defined. We examined the alteration of the coagulation and fibrinolysis system in COPD patients according to the right ventricular function measured using cardiac multidetector computed tomography (MDCT). Methods: The right ventricular ejection fraction (RVEF) was measured using cardiac MDCT in 26 patients who were diagnosed with COPD according to the definition of the GOLD guideline. The plasma level of thrombin antithrombin (TAT) and plasminogen activator inhibitor (PAI)-1 were measured using an enzyme linked immunoassay. Results: The plasma TAT was markedly elevated in COPD patients ($10.5{\pm}19.8{\mu}g/L$) compared with those of the control ($3.4{\pm}2.5{\mu}g/L$) (p<0.01). However, the plasma PAI-1 in COPD patients ($29.6{\pm}20.7ng/mL$) was similar to that in the controls. The plasma TAT showed a significant inverse relationship with the RVEF measured by the cardiac MDCT in COPD patients (r=-0.645, p<0.01). However, the plasma PAI-1 did not show a relationship with the RVEF (r=0.022, p=0.92). Conclusion: These results suggest that the coagulation system in COPD patients is markedly activated, and that the plasma level of TAT might be a marker of a right ventricular dysfunction in COPD patients.

Influence of Sulfur and Fluorine Compounds on the Growth and Yield of Rice Plants;I. Growth Retardation and Yield Reduction under Various Stressed Conditions in the Field (황화물(黃化物) 및 불화물(弗化物)이 수도생육(水稻生育)과 수량(收量)에 미치는 영향(影響);I. 오염지역(汚染地域)에서의 생육장해(生育障害) 및 수량감소(收量減少))

  • Park, Wan-Cheol;Shin, Eung-Bai;Kim, Kwang-Ho
    • Korean Journal of Environmental Agriculture
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    • v.6 no.2
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    • pp.53-65
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    • 1987
  • The study was performed to investigate the effect of gaseous emissions of sulfur dioxide and hydrogen fluoride on the growth of rice plants under stressed field conditions consisting of 88 industrial plants operating with 285 smoke stacks emitting pollutants. As for the relationship between yields and yield components it is believed that the panicles per hill is the single most important component affecting the rate of yield of the rice plant. Based on the standard partial regression coefficient analysis, panicles per hill has the largest contribution to yield and the average contribution of 54%. Other components such as spikelets per panicle, percent fertility and 1000 grain weight are also contributing factors to yield, although far less so. Fluorine content in the leaf appear to have more negative effect on panicles per hill, percent fertility and subsequent overall yield than does sulfur content in the leaf. It is constantly observed and interesting to note that fluorine and sulfur content in the leaf appears to have no effect on spikelets per panicle and 1000 grain weight. Reduction in yield seems to be affected mainly by panicles per hill which are, in turn, affected more by fluorine content in the leaf as demonstrated by the standard partial coefficient analysis. Regarding the prediction sum of the square of the regression equation, the lowest value was found when nine variables were used for the analysis. The variables taken into consideration were the monthly sulfur and fluorine content in the leaf as well as the monthly percent of leaf damage during the months of June, July and August. A significant correlation is found between the actual and predicted yields by the regression equations selected as a result of a prediction sum of the square analysis.

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