• Journal of Bio-Environment Control
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• v.20 no.2
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• pp.93-100
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• 2011

Maintenance of adequate soil water potential during the period of crop growth is necessary to support optimum plant growth and yields. A better understanding of soil water movement within and below the rooting zone can facilitate optimal irrigation scheduling aimed at minimizing the adverse effects of water stress on crop growth and development and the leaching of water below the root zone which can have adverse environmental effects. The objective of this study was to evaluate the feasibility of using a portable irrigation controller with an Watermark sensor for the cultivation of drip-irrigated vegetable crops in a greenhouse. The control capability of the irrigation controller for a soil water potential of -20 kPa was evaluated under summer conditions by cultivating 45-day-old tomato plants grown in three differently textured soils (sandy loam, loam, and loamy sands). Water contents through each soil profile were continuously monitored using three Sentek probes, each consisting of three capacitance sensors at 10, 20, and 30 cm depths. Even though a repeatable cycling of soil water potential occurred for the potential treatment, the lower limit of the Watermark (about 0 kPa) obtained in this study presented a limitation of using the Watermark sensor for optimal irrigation of tomato plants where -20 kPa was used as a point for triggering irrigations. This problem might be related to the slow response time and inadequate soil-sensor interface of the Watermark sensor as compared to a porous and ceramic cup-based tensiometer with a sensitive pressure transducer. In addition, the irrigation time of 50 to 60 min at each of the irrigation operation gave a rapid drop of the potential to zero, resulting in over irrigation of tomatoes. There were differences in water content among the three different soil types under the variable rate irrigation, showing a range of water contents of 16 to 24%, 17 to 28%, and 24 to 32% for loamy sand, sandy loam, and loam soils, respectively. The greatest rate increase in water content was observed in the top of 10 cm depth of sandy loam soil within almost 60 min from the start of irrigation.

• Journal of Chest Surgery
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• v.34 no.6
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• pp.454-464
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• 2001

Background: It has been recognized that systemic inflammatory reaction and oxygen free radical formed by activated leukocyte in the procedure of cardiopulmonary bypass(CPB) frequently produce postoperative cardiac and pulmonary dysfunction. The purpose of this study was to evaluate the efficacy of leukocyte-depleting filters in the cardiopulmonary bypass circuit for patients undergoing open heart surgery(OHS). Material and method: The study involved 15 patients who underwent OHS with a Leukoguard-6 leukocyte filter placed in the arterial limbs of the bypass circuit(filter group, n=15) and 15 patients who did not have the filter(control group, n=15). We analyzed the differences between the groups in intraoperative changes of peripheral blood leukocyte and platelet counts, pre- and postbypass changes of malondialdehyde(MDA), troponin-T(TnT), 5'-nucleotidase(5'-NT) in coronary sinus blood, spontaneous recovery rate of heart beat after CPB, pre-and postoperative cardiac index(Cl) and pulmonary vascular resistance(PVR), and the amounts of postoperative bleeding and sternal wound complication. Result: During CPB, total leukocyte count of the filter group(9,567$\pm$ 842/㎣) was significantly less than that of the control group(13,573+1,167/㎣) (p<0.01), but there was no significant difference in platelet count between the groups. Postoperative levels of MDA(3.78+0.32 $\mu$mol/L vs 5.86+0.65 $\mu$mo1/L, p<0.01), TnT(0.40$\pm$0.04 ng/mL vs 0.59$\pm$0.08 ng/mL, p<0.05) and 5'-NT(3.88$\pm$0.61 U/L vs 5.80$\pm$0.90 U/L, p<0.05) were all significantly lower in the filter group than the control group. Postoperative Cl was higher in the filter group than the control group(3.26$\pm$0.18 L/$m^2$min vs 2.75$\pm$0.17 L/$m^2$/min, p=0.05). PVR of the filter group was lower than that of the control group(65.87$\pm$7.59 dyne/sec/cm$^{5}$ vs 110.80+12.22 dyne/sec/cm$^{5}$ , p<0.01). Spontaneous recovery rate of heart beat in the filter group was higher than that in the control group(12 patients vs 8 patients, p<0.05). Postoperative wound infection occurred in one case in the filter group and 4 case in the control group(p<0.05). Postoperative 24 hour blood loss of the filter group was more than that of the control group (614$\pm$107 mL vs 380+71 mL, p=0.05).

• The Journal of Engineering Geology
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• v.22 no.2
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• pp.145-155
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• 2012

The matric suction and volumetric water content of Jumunin standard sand with a relative density of 60% were measured using an Automated Soil-Water Characteristic Curve (SWCC) apparatus during both drying and wetting processes. The test time for the drying process was longer than that for the wetting process, because the flow of water is likely to be protected by air trapped in voids within the soils during the drying process. Based on the matric suction and volumetric water content, the SWCC was estimated using the model proposed by van Genuchten (1980). For the drying process, the unsaturated fitting parameters ${\alpha}$, n, and m were 0.399, 8.586, and 0.884, respectively; for the wetting process, the values were 0.548, 5.625, and 8.220, respectively. The hysteresis phenomenon occurred in the SWCCs, which means the SWCC of the drying process is not matched with the SWCC of the wetting process. Using these unsaturated parameters, we estimated the Suction Stress Characteristic Curve (SSCC), based on the relationship between suction stress and the effective degree of saturation. The suction stress showed a rapid decrease when the matric suction exceeds the Air Entry Value (AEV). Therefore, the effective stress of unsaturated soils is different from that of saturated soils when the matric suction exceeds the AEV. The suction stress of the drying process exceeds that of the wetting process for a given effective degree of saturation. The hysteresis phenomenon was also recognized in SSCCs. The hysteresis phenomenon of SSCCs arises from that of SWCCs, which is induced by the ink bottle effect and the contact angle effect. In the case of a sandy slope, the suction stress is positive and acts to enhance the slope stability as the water infiltrates the ground, but is negative when the suction stress exceeds the AEV. The results obtained for the wetting process should be applied in analyses of slope stability, because the process of water infiltration into ground is similar to the wetting process.

• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.2
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• pp.213-230
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• 2008

The aim of this study was to analyze the initial movement and the stress distribution of each tooth and periodontal ligament during the lingual lever-arm retraction of 6 maxillary incisors using FEA. Two kinds of finite element models were produced: 2-properties model (simple model) and 24-properties model (multi model) according to the material property assignment. The subject was an adult male of 23 years old. The DICOM images through the CT of the patient were converted into the 3D image model of a skull using the Mimics (version 10.11, Materialise's interactive Medical Image Control System, Materialise, Belgium). After series of calculating, remeshing, exporting, importing process and volume mesh process was performed, FEA models were produced. FEA models are consisted of maxilla, maxillary central incisor, lateral incisor, canine, periodontal ligaments and lingual traction arm. The boundary conditions fixed the movements of posterior, sagittal and upper part of the model to the directions of X, Y, Z axis respectively. The model was set to be symmetrical to X axis. Through the center of resistance of maxilla complex, a retraction force of 200g was applied horizontally to the occlusal plane. Under this conditions, the initial movements and stress distributions were evaluated by 3D FEA. In the result, the amount of posterior movement was larger in the multi model than in the simple model as well as the amount of vertically rotation. The pattern of the posterior movement in the central incisors and lateral incisors was controlled tipping movement, and the amount was larger than in the canine. But the amount of root movement of the canine was larger than others. The incisor rotated downwardly and the canines upwardly around contact points of lateral incisor and canine in the both models. The values of stress are similar in the both simple and multi model.