• Korean Journal of Soil Science and Fertilizer
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• v.31 no.1
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• pp.67-71
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• 1998

This study was carried out to granulate artificial zeolite powder that remove ammonium nitrogen and phosphorous simultaneously in wastewater treatment. Optimum water content was required for 30 percent volume to granulate artificial zeolite with 1.7mm diameter and 1~2cm length using granulator. Portland cement could remove much $NH_4{^+}$ and $PO_4{^{3-}}$ from the wastewater than other binding materials. Mixed 33, 25. 20. 16 percent of portland cement to artificial zeolite powder(v/v), cation exchange capacity of the granulars were 66.5, 81.4, 126.8, $151.2cmol^+kg^{-1}$ and hardness of that were 176.1, 24.4, 4.1, $0.4kg\;cm^{-2}$, respectively. Content of portland cement in the granular were related with removal of $PO_4{^{3-}}$ positively and that of $NH_4{^+}$ negatively. Shaked 1g of the granulars that made of portland cement 33 percent with 40ml synthetic wastewater containing $NH_4{^+}$ $1545mgl^{-1}$ and $PO_4{^{3-}}$ $417mgl^{-1}$, 99.4 percent of $NH_4{^+}$ and 90.3 percent of $PO_4{^{3-}}$ were removed simultaneously after 48 hours shaking. The longer shaking, the more $NH_4{^+}$ and $PO_4{^{3-}}$were removed. The artificial zeolite granular had both micropore and macropore that could be useful in the wastewater purification.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.4
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• pp.446-451
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• 1999

This study was carried out to investigate some mineralogical characteristics of Artificial Granular Zeolite (AGZ) and effect of AGZ on purification and alleviation of rice seedling damages of mine wastewater containing heavy metals. AGZ had mainly representative Na-P1 peaks and some $C_3S$ peaks of Portland cement in X-ray diffractogram. Differential thermal analysis represented that AGZ had weak endothermic peak around $130^{\circ}C$ and new deep endothermic peak around $750^{\circ}C$ as compared to powdery artificial zeolite. The ranking of heavy metals removals by AGZ, was lead> copper> cadmium> zinc in the synthetic wastewater. Root growth of rice seedling was greatly inhibited in the mine wastewater, and died after all. As AGZ treated into the mine wastewater with the ratio 1 : 50 (W : V) for one day or 1 : 100 for 4 days, the concentrations of heavy metals in the mine wastewater were decreased to below the critical concentration for agricultural use. And rice seedlings were grew with little damages in the purified water by AGZ.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.331-336
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• 2011

Capacitance soil moisture sensor is extensively used by soil research and irrigation management with its convenience and accuracy. This experiment was conducted to evaluate the acceptability of capacitance soil moisture sensor, named EnviroSCAN made by Sentek Ltd., in Jeju Island where volcanic ash soils are widely distributed, and to calibrate it to various soils with different amount of soil organic matter. For sensor calibration equation of volcanic ash soils, a logarithm function is better than a typical power function of non-volcanic ash soils. So there are possibilities of under evaluated in soil water contents in very wet and very dry conditions by using typical power function with volcanic ash soil areas. We suggested practical coefficients of typical calibration equation for using capacitance sensor in volcanic ash soils, also suggested equations for estimation of them with soil organic matter contents. The measurement of soil water content with a capacitance sensor can be affected by some soil characteristics such as porosity, soil organic matter content, EC, etc. So those factors should be controlled for improving the accuracy of measurement.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.763-774
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• 2021

The COVID-19 virus has generated major shockwaves in all spheres of human life since its outbreak. Maritime transport (both cargo and passenger) is one of the industries most heavily affected, yet over 80% of the world cargo is transported by sea. This study analyzes maritime port operational efficiencies before and after the start of the COVID-19 pandemic to determine whether the pandemic has caused major differences in the operational efficiencies of many leading Asian maritime container ports via data envelopment analysis (DEA). The results of both the CCR and BCC models reveal that overall, efficiency during the COVID-19 pandemic has been higher than before the pandemic despite a few inefficiencies. This implies that the pandemic has so far not has major consequences for the operational efficiency of maritime ports. However, two ports (Busan and Guangzhou) should adjust the scale sizes and technical capacities of their operations to improve performance.

• Journal of fish pathology
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• v.34 no.2
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• pp.185-199
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• 2021

Vibriosis is an important septicemic bacterial disease that affects a variety of commercial fish species, including cultured Dicentrarchus labrax. Nanotechnology has become an important modern tool for fish diseases prevention. Furthermore, nanomaterials have the ability to prevent and treat fish diseases. The current study was aimed to identify the causative agent of massive mortality of D. labrax commercial farm in Alexandria, Egypt. Experimental infection and the median lethal dose (LD50) of pathogenic isolate were assessed. Also, the effect of ginger nanoparticles (GNPs) and Sacchromyces cerevisiae as feed additives for prevention of vibriosis in D. labrax was carried out. Similarly, the tissue immunstimulant genes, IL-1β and TLR2 were measured in the spleen of feeding groups. The clinical signs of naturally diseased D. labrax showed corneal opacity and paleness of gills with excessive mucous secretion. The post-mortem abnormalities were severe hemorrhage and adhesion of internal organs. After bacteriological isolation and identification, the causative agent of mortality in the current study was Vibrio alginolyticus. The LD₅₀ of V. alginolyticus was 1.5×10^5.4 CFU/ml. The experimentally infected D. labrax showed ulceration, exophthalmia and skin hemorrhages. The post-mortem findings of the experimentally infected D. labrax revealed internal hemorrhage, spleen darkness and paleness of liver. There is no mortality and 100% RPS in groups fed GNPs then injected with V. alginolyticus, in those fed a combination of GNPs and S. cerevisiae and a group fed normal diet then injected with physiological saline (control negative), respectively. Contrarily, there was 10% mortality and 87.5 RPS in the group fed S. cerevisae then injected with V. alginolyticus. On the other hand, the control positive group showed 79% mortality. The spleen IL-1β and TLR2 immunostimulant genes were significantly increased in groups of fish fed GNNP, S. cerevisiae and a combination of GNPs and S. cerevisiae, respectively compared to control group. The highest stimulation of those immunostimulant genes was found in the group fed a combination of GNPs and S. cerevisiae, while fish fed S. cerevisiae had the lowest level. Dietary combination of GNPs and S. cerevisiae was shown to be efficient in preventing of vibriosis, with greatest stimulation of spleen IL-1β and TLR2 immunostimulant genes.

• Journal of Digital Convergence
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• v.19 no.9
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• pp.105-114
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• 2021

The paper investigates a mediating effect of job embeddedness in the influence of positive psychological capital on organizational citizenship behavior(OCB) for members of medical institutions. The members include medical doctors, nurses, medical technicians, health administrative staffs, and other medical service staffs of hospitals in Daejeon City, Chungcheongnam-do, Chungcheongbuk-do, and Sejong City. Using 453 questionnaires for hypothesis tests, the main results are as follows. Firstly, positive psychological capital exerts a significantly positive effect on OCB. Secondly, the fit and links of job embeddedness turn out to have a significant and positive effect on OCB, whereas the sacrifice does not have statistically significant effect on it. Thirdly, while the fit and links of job embeddedness appear to have mediating effects between positive psychological capital and OCB, the sacrifice of it does not exert a mediating effect. The findings thus suggest that we need a new approach to the role of job embeddedness in the positive impacts of positive psychological capital on OCB through the fit and links of job embeddedness. Furthermore, organizations need to focus on key elements in the application of job embeddedness.

• Journal of Convergence for Information Technology
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• v.11 no.10
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• pp.223-229
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• 2021

This study analyzed the effects of an exercise program that combined lumbar stabilization exercise and muscle strengthening exercise and an exercise program that applied only lumbar muscle strengthening exercise on multifidus muscle cross-sectional area, static posture control ability, and low back pain in patients with CLBP. For the study method, 28 patients with CLBP were divided into two exercise propram groups and exercised three times a week for 8-weeks. The data analysis of this study used the t-test to compare before and after group exercise program application, and between each group (p<.05). As a result of the study, significant results were found before and after application of the exercise program within each group, such as multifidus muscle cross-sectional area, static posture control ability, and low back pain (p<.05). Between each group, the exercise program that combined lumbar stabilization exercise and muscle strengthening exercise was found to be more effective (p<.05). In conclusion, it was found that the exercise program with additional lumbar stabilization exercise improved the structure and function of various lumbar vertebrae and reduced lumbar pain.

• Journal of Family Resource Management and Policy Review
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• v.25 no.4
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• pp.87-99
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• 2021

The life of middle-aged one-person households is rising as one of the most important family policy issues in Korean society. In Japan, even in multi-person households, the issues of middle-aged sons and daughters living with their old parents have been a concern. Data are from the 13^th wave of the Korea Welfare Panel Study analyzing 482 middle-aged singe males regardless of their past marital status. The purpose of this study is to investigate the effects of human capital and social capital on the life satisfaction of middle-aged single persons by comparing one-person and multi-person households, respectively. Major results were as follows: First, the level of human capital of one-person households of middle aged males was lower than their counterparts in multi-person households. Second, the level of social capital in the group of divorced or widowed, nonhouseholder middle-aged males in multi-person households was lower than their counterparts in one-person households. Third, the effects of human capital and social capital on life satisfaction was significantly different by their marital status and household types in the group of middle-aged single males. Based on the results, policy implications on the community programs for middle-aged males including not only one-person households but also multi-person households were discussed.

• International Journal of Computer Science & Network Security
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• v.21 no.7
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• pp.17-34
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• 2021

This study aimed to examine the Factor Structure of the teacher satisfaction scale (TSS) with distance education during the Covid-19 pandemic, as well as affirming the (Factorial Invariance) according to gender variable. It also aimed at identifying the degree of satisfaction according to some demographic variables of the sample. The study population consisted of all teachers in public education and faculty members in higher education in the Kingdom of Saudi Arabia. The (TSS) was applied to a random sample representing the study population consisting of (2399) respondents. The results of the study showed that the scale consists of five main factors, with a reliability value of (0.94). The scale also showed a high degree of construct validity through fit indices of the confirmatory factor analysis. The results have shown a gradual consistency of the measure's invariance that reaches the third level (Scalar-invariance) of the Measurement Invariance across the gender variable. The results also showed that the average response of the study sample on the scale reached (3.74) with a degree of satisfaction, as there are no statistically significant differences between the averages of the study sample responses with respect to the gender variable. While there were statistically significant differences in the averages with respect to the variable of the educational level in favor of the middle school and statistically significant differences in the averages attributed to the years of experience variable in favor of those whose experience is less than (5) years.

• Animal Bioscience
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• v.34 no.10
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• pp.1616-1622
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• 2021

Objective: Bioactive compounds in ruminant products are related to functional compounds in their diets. Therefore, this study aimed to explore the effect of forage sources, Italian ryegrass (IR) silage vs corn silage (CS) in the total mixed ration (TMR), on milk production, milk composition, and phytanic acid content in milk, as well as on the extent of conversion of dietary phytol to milk phytanic acid. Methods: Phytanic acid content in milk was investigated for cows fed a TMR containing either IR silage or CS using 17 cows over three periods of 21 days each. In periods 1 and 3, cows were fed CS-based TMR (30% CS), while in period 2, cows were fed IR silage-based TMR (20% IR silage and10% CS). Results: The results showed that there were no differences in fat, protein, lactose, solids-not-fat, somatic cell count, and fatty acid composition of milk among the three experimental periods. There were no differences in the plasma concentration of glucose, triglycerides, total cholesterol, and nonesterified fatty acids among the three experimental periods, while the blood urea nitrogen was higher (p<0.05) in period 2. The milk phytanic acid content was higher (p<0.05) in period 2 (13.9 mg/kg) compared with periods 1 (9.30 mg/kg) and 3 (8.80 mg/kg). Also, the phytanic acid content in the feces was higher (p<0.05) in period 2 (1.65 mg/kg dry matter [DM]) compared with period 1 (1.15 mg/kg DM), and 3 (1.17 mg/kg DM). Although the phytol contents in feces did not differ among the three feeding periods, the conversion ratio from dietary phytol to milk phytanic acid was estimated to be only 2.6%. Conclusion: Phytanic acid content in cow's milk increases with increasing phytol content in diets. However, phytol might not be completely metabolized in the rumen and phytanic acid, in turn, might not be completely recovered into cow's milk. The change of phytanic acid content in milk may be positively correlated with the change of phytol in the diet within a short time.