• 한국농림기상학회지
• /
• 제7권3호
• /
• pp.185-191
• /
• 2005

An accurate prediction of dormancy release and bud burst in temperate zone fruit trees is indispensable for farmers to plan heating time under partially controlled environments as well as to reduce the risk of frost damage in open fields. A thermal time-based two-step phenological model that originated in Italy was applied to two important grapevine cultivars in Korea for predicting bud-burst dates. The model consists of two sequential periods: a rest period described by chilling requirement and a forcing period described by heating requirement. It requires daily maximum and minimum temperature as an input and calculates daily chill units (chill days in negative sign) until a pre-determined chilling requirement for rest release is met. After the projected rest release date, it adds daily heat units (anti-chill days in positive sign) to the chilling requirement. The date when the sum reaches zero isregarded as the bud-burst in the model. Controlled environment experiments using field sampled twigs of 'Campbell Early' and 'Kyoho' cultivars were carried out in the vineyard at the National Horticultural Research Institute (NHRI) in Suwon during 2004-2005 to derive the model parameters: threshold temperature for chilling and chilling requirement for breaking dormancy. The model adjusted with the selected parameters was applied to the 1994-2004 daily temperature data obtained from the automated weather station in the NHRI vineyard to estimate bud burst dates of two cultivars and the results were compared with the observed data. The model showed a consistently good performance in predicting the bud burst of 'Campbell Early' and 'Kyoho' cultivars with 2.6 and 2.5 days of root mean squared error, respectively.

• 한국도로학회논문집
• /
• 제18권5호
• /
• pp.39-47
• /
• 2016

PURPOSES : Road subsidence occurs owing to road cavities, which cause many social and environmental problems, especially in cities. Recently, road cavities were detected by various ground radars and repair works were carried out against the detected cavities. The condition assessments related to the road cavities are necessary to understand the potential risk of the cavities. Therefore, in this study, a numerical study was performed to assess the various conditions of road cavities. METHODS : The numerical method adopted in this study is the discrete element approach, and it is suitable for analyzing the condition because it can consider the movement of the soil particles in the surrounded cavity areas. In addition, the triaxial test was modeled and performed under various cavity conditions inside the specimens. RESULTS : The conditions of different cavity locations and shapes were analyzed to identify the effect of cavity state. Three general cases of particle size distributions were formulated to identify the effect of surrounding ground conditions. As a result, the degree of decrement and volumetric strain were varied depending on the locations and shapes of the cavity. Only minor changes were observed when the particle size distributions were altered. CONCLUSIONS : The strength reduction was higher when the cavity formed was larger and located in the upper zone. Similar to the cavity shape, strength reduction and volume deformation are more influenced by the width than the length of the cavities. There is an influence from ground conditions such as the particle size distribution, especially on the wide cavity.

• 한국산업보건학회지
• /
• 제11권1호
• /
• pp.1-8
• /
• 2001

This study was performed to evaluate a local exhaust ventilation system capability and welding fume concentration in welding laboratory at 5 technical high schools. Results of the study are as follows; 1. The personal exposure of welding fume in welding laboratory was measured. The geometric mean of 73 personal samples was $6.27mg/m^3$($3.85{\sim}9.88mg/m^3$), and 68.5% of these exceeded TLV of the Korea Ministry of Labor. 2. The geometric mean of welding fume at outside of booth was $2.27mg/m^3$($1.57{\sim}2.58mg/m^3$). All of measured concentrations were lower than TLV of the Korea Ministry of Labor. 3. Local exhaust ventilation system in welding laboratory could not remove hazardous substance effectively because of inappropriate canopy hood and absurd design. 4. The possibility of exposure risk was estimated to be high because of working point under breathing zone, misplacement of working table and insufficient supply of respiratory protector. 5. The mean values of capture velocity and transportation velocity of local exhaust ventilation system in welding laboratory were 0.38m/sec, 4.27m/sec respectively. These values were satisfied the guideline of the Korea Ministry of Labor. 6. The efficiency of performance of local ventilation system was anticipated to be decreased because of accumulated dust and alien substance on fan and duct.

• Journal of Biosystems Engineering
• /
• 제33권3호
• /
• pp.151-156
• /
• 2008

This study was conducted to evaluate ride vibrations experienced by tractor operators during plowing, rotovating, and transporting operations in Korea. Field data of ride vibrations were taken at the operator-seat interface from 49 tractors and analyzed on the basis of ISO 2631-1 and EU Directive 2002/44. Of the measured ride vibrations 15.4% in the plowing and 12.5% in farm road transport exceeded the 8-hour fatigue decreased proficiency boundary in the fore and aft directions at frequencies from 1 to 5 Hz. 93.9% exceeded the 8-hour potential health risk of ISO 2631-1. The ride vibrations exceeding the 8-hour exposure limit were 38.5% in plowing, 31.6% in rotovating, 100% in farm road transport and 88.9% in concrete road transport. Although most tractor operators were not exposed to ride vibrations greater than the 8-hour exposure limit value (ELV) of EU Directive 2002/44, 7.7% of the operators in the plowing experienced greater vibrations than the ELV in the fore-aft direction. Farm road transport produced greater vibrations than any other operations. Concrete road transport, plowing and rotovating operations followed next. Limit criteria for ride vibration exposure differ depending upon the guidelines. Exposure limit of the health guidance caution zone of ISO 2631-1 is lowest among its kinds.

• Nutritional Sciences
• /
• 제2권2호
• /
• pp.71-75
• /
• 1999

Epidemiologic studies consistently demonstrate an inverse relationship between risk for colon canter and consumption of fruits and vegetables. Wheat bran, flax and soy contain dietary fiber and phytochemicals, such as lignans and isoflavones, that may inhibit colon carcinogenesis. Orange juice contains hesperidin, a flavanone glucoside that protects against colon carcinogenesis. This study determined if feeding orange juice, wheat bran, soy and flaxseed (combined diet) would inhibit azoxymethane (AOM) induced colon cancer. Cancer was initiated in male Fisher 344 rats by injecting 15 mg AOM/kg of weight at 22 and 29 days of age. One week after the second AOM injection, rats (N = 30) in the combined diet group received dry diet containing wheat bran (4%), soy with ethanol soluble phytochemirals(13%) and flaxseed (8%) and orange juice replaced drinking water. The control group remained on the control diet and received distilled water to drink. The rats were killed 28 weeks later, and colon tissues and tumors were removed for histologic analysis. Feeding the combined diet significantly reduced tumor incidence (p < 0.05), however tumor multiplicity was not changed (p > 0.05, 0.9 tumors/rat fed the combined diet vs 1.2 for controls). Also, tumor burden was only marginally reduced in rats fed the combined diet vs control rats (65 vs 210 mg of tumor/rats, respectively). The reduction in tumor incidence was associated with a decreased labeling index and proliferation zone in normal appearing colon mucosa. Therefore, this study shows that phytochemicals in wheat bran, soy, flax and orange juice reduce colon carcinogenesis, presumably by decreasing cell proliferation and enhancing cell differentiation.

• Earthquakes and Structures
• /
• 제12권1호
• /
• pp.135-144
• /
• 2017

Near-fault ground motions are characterized by high values of the ratio between the peak of vertical and horizontal ground accelerations, which can significantly affect the nonlinear response of a base-isolated structure. To check the effectiveness of different base-isolation systems for retrofitting a r.c. framed structure located in a near-fault area, a numerical investigation is carried out analyzing the nonlinear dynamic response of the fixed-base and isolated structures. For this purpose, a six-storey r.c. framed building is supposed to be retrofitted by insertion of an isolation system at the base for attaining performance levels imposed by current Italian code in a high-risk seismic zone. In particular, elastomeric (e.g., high-damping-laminated-rubber bearings, HDLRBs) and friction (e.g., steel-PTFE sliding bearings, SBs, or friction pendulum bearings, FPBs) isolators are considered, with reference to three cases of base isolation: HDLRBs acting alone (i.e., EBI structures); in-parallel combination of HDLRBs and SBs (i.e., EFBI structures); FPBs acting alone (i.e., FPBI structures). Different values of the stiffness ratio, defined as the ratio between the vertical and horizontal stiffnesses of the HDLRBs, sliding ratio, defined as the global sliding force divided by the maximum sliding force of the SBs, and in-plan distribution of friction coefficient for the FPs are investigated. The EBI, EFBI and FPBI base-isolation systems are designed assuming the same values of the fundamental vibration period and equivalent viscous damping ratio. The nonlinear dynamic analysis is carried out with reference to near-fault earthquakes, selected and scaled on the design hypotheses adopted for the test structures.

• Journal of Nutrition and Health
• /
• 제31권1호
• /
• pp.21-27
• /
• 1998

The objective of this study was to observe the effect of dietary calcium(Ca) level on colonic mucosal levels of cell proliferation, 1, 2-diacylglycerol(DAG), TXB2, PGE2 and phospholipid fatty acid composition which have been known as biomarkers for colon cancer. One hundred male Sprague Dawley rats, at 7 weeks of age, were divided into two fat type groups. Each group of which was further divided into two Ca level groups. Each rt was intramuscularly injected with 1, 2,-dimenthylhydrazine(DMH) for 6 weeks (total dose of 180mg/kg body weight) and simultaneously fed one of four experimental diets containing 15% dietary fat(corn oil or perilla oil )and 0.3% or 1.0% Ca by weight for 20 weeks. Compared to corn oil, perilla oil significantly reduced cell proliferation by decreasing labeling index, proliferating zone, crypt length in colonic mucosa and colonic mucosa and colonic mucosal levels of DAG, TXB2 . PGE2 and phospolipid (PL) arachidonic acid distribution. The effect of Ca on biomarketrs was different depending on the type of dietary fat comsumed . Ca effect of Ca on biomarkers was different depending on the type of dietary fat comsumed. Ca effect was not significantly shown in the PO group, but it was significant in the CO group in which high Ca(1.0%) decreased the levels of levels of PL-C20 : 4(%), DAG and PGE2 . However , high Ca supplementation had shown only the trends of improving cell proliferation. Overall , high dietary Ca significantly reduced cell proliferation by inhibiting the synthesis of eicosanoid and DAG with reduced distribution of PL-C20 : 4 , which may have resulted in lower activation of PKC through reduced signal transduction. Since a high level of dietary Ca was more effective in reducing the risk factor against colon cancer in corn oil fed rats, it could be suggested that a higher amount of dietary Ca be consumed , especially when more vegetable oil rich in linoleic acid is included in the diet.

• 한국약용작물학회지
• /
• 제12권5호
• /
• pp.406-414
• /
• 2004

Resveratrol, which is both a phytoalexin with antifungal activity and a phytochemical associated with reduced cancer risk and reduced cardiovascular disease, is synthesized in a limited number of plant species including peanut. Resveratrol synthesis is catalyzed by the enzyme stilbene synthase including resveratrol synthase (RS). Resveratrol synthase gene (RS3) obtained from peanut, Arachis hypogaea, Fabaceae has been transferred into chinese foxglove, Rehmannia glutinosa by using Agrobacterium mediated transformation. RS t-DNA introduced to chinese foxglove (R. glutinosa L) by transformation and its reaction product, $resveratrol-3-O-{\beta}-D-glucoside$ was isolated and characterized using HPLC. Also its biological effects was tested in inhibition of the lipid peroxidation of mouse LDL by glycosylated stilbenes derivatives obtained from transgenic plants. $Resveratrol-3-O-{\beta}-D-glucoside$ isolated from transgenic R. glutinosa L. showed antimicrobial activity of the growth inhibition zone against Escherichia coli and Salmonella typhimurium. Therefore, this compound can be contributed to be useful as a phytoalexin for plant health as well as a phytochemical for human health.

• Asian Pacific Journal of Cancer Prevention
• /
• 제16권18호
• /
• pp.8495-8501
• /
• 2016

Purpose: This study was conducted to assess the agreement and differences between cervical self-sampling with a Kato device (KSSD) and gynecologist sampling for Pap cytology and human papillomavirus DNA (HPV DNA) detection. Materials and Methods: Women underwent self-sampling followed by gynecologist sampling during screening at two primary health clinics. Pap cytology of cervical specimens was evaluated for specimen adequacy, presence of endocervical cells or transformation zone cells and cytological interpretation for cells abnormalities. Cervical specimens were also extracted and tested for HPV DNA detection. Positive HPV smears underwent gene sequencing and HPV genotyping by referring to the online NCBI gene bank. Results were compared between samplings by Kappa agreement and McNemar test. Results: For Pap specimen adequacy, KSSD showed 100% agreement with gynecologist sampling but had only 32.3% agreement for presence of endocervical cells. Both sampling showed 100% agreement with only 1 case detected HSIL favouring CIN2 for cytology result. HPV DNA detection showed 86.2%agreement (K=0.64, 95% CI 0.524-0.756, p=0.001) between samplings. KSSD and gynaecologist sampling identified high risk HPV in 17.3% and 23.9% respectively (p=0.014). Conclusion: The self-sampling using Kato device can serve as a tool in Pap cytology and HPV DNA detection in low resource settings in Malaysia. Self-sampling devices such as KSSD can be used as an alternative technique to gynaecologist sampling for cervical cancer screening among rural populations in Malaysia.

• 한국수소및신에너지학회논문집
• /
• 제26권2호
• /
• pp.114-119
• /
• 2015

Nowdays, fossil fuels have been used as an important resource in development of industry. But it is limited and caused climate change such as pollution and global warming. So nuclear fusion research is being issued with tritium to develop eco-friendly and sustainable energy. Republic of Korea is in charge of Storage and Delivery System (SDS) in the International Thermonuclear Experimental Reactor (ITER), weld present in the SDS bottles are easily exposed to the hydrogen embrittlement of special characteristics of the hydrogen in hydrogen atmosphere, When the hydrogen embrittlement is rapidly progresses, the cracking is generated in the weld zone. Due to this cracking, the risk of leakage of tritium into the atmosphere occurs. In this study, hydrogen heat treatment was processed through the Pressure-Composition-Temperature (PCT) device according to the time variation. Also mechanical properties such as rupture strength test, three point bend test and hardness test in accordance with the respective time have been conducted and the fracture was observed by scanning electron microscopy(SEM) after the mechanical properties evaluation.