• Journal of the Korea institute for structural maintenance and inspection
• /
• v.17 no.4
• /
• pp.57-65
• /
• 2013

The development of the oil refining industry has resulted in an annual 120 million tons of sulphur, which is a by-product of the desulphurization process. To exploit this abundance, the applications of sulphur must be expanded. as excellent durability of reuse of leftover sulphur which has high potential for utilization in construction materials, the study is actively in progress. Meanwhile, there has been active research on semi-rigid pavements that draw on the strengths and overcome the weaknesses of asphalt and concrete pavements. Acrylate is used to prevent cracking but involves a high cost, thus, an alternative material is required. As such, this study presents methods on the reuse of leftover sulphur and examines the engineering performance of grout containing sulfur polymer emulsion (SPE) for use in semi-rigid pavements. Our analysis shows that grout in which 30% of acrylate is replaced with SPE has superior properties in terms of time of flow and strength compared to regular grout. However, performance declined when more than 50% of acrylate was replaced by SPE, indicating that the optimum replacement level is 30%. Through SEM analysis, we found that grout with utra harding cement in this study at three hours had similar hydration properties to that of Type 1 Ordinary Portland Cement (OPC) at seven days, and maintained the properties regardless of grout containing SPE. OPC and grout with a replacement level of 30% displayed similar levels of chloride invasion resistance, whereas grout without SPE was far less resistant. Within the scope of this paper, the optimum replacement level of acrylate with SPE was found to be 30% in consideration of various properties such as time of flow, strength, and chloride invasion resistance.

• International Journal of Highway Engineering
• /
• v.7 no.3 s.25
• /
• pp.79-91
• /
• 2005

The temperature patterns in Portland cement concrete (PCC) pavements were measured and comprehensively analyzed from the beginning of the concrete placement based on the temperature measurement technique developed using innovative and inexpensive temperature measurement sensors. The temperature measurements in PCC pavements were taken at several different locations forvarious slab thicknesses. The concrete temperature patterns in the vertical and longitudinal directions of the pavement were analyzed and the effects of the pavement surface reflectivity, shading, and covering on the concrete temperatures were evaluated. The results of this study showed that the significant differences in the maximum concrete temperatures on the placement day were observed according to the concrete placement time. Since the zero-stress temperature is a function of the maximum concrete temperature on the placement day, the placement time would be an important factor that affects the behavior and performance of concrete pavements. The surface conditions of the pavement, such as the surface color, shading, and covering also affected the temperature patterns in PCC pavements significantly.

• Food Science and Preservation
• /
• v.19 no.5
• /
• pp.626-632
• /
• 2012

In this study, the changes that occurred in the quality of minimally processed sliced Deodeok (Codonopsis lanceolata) in relation to the packing method during storage at $7^{\circ}C$ were investigated. The storage tests were conducted for seven days using PE sealing, but PP sealing and vacuum packaging preserved the Deodeok for 14 days. On the seventh day, the vinyl-packaged Deodeok showed a remarkable fall in quality with 4.5 °Brix, but the PP-sealed and vacuum-packaged Deodeok showed slight falls with 6.4 and $6.8^{\circ}Brix$, respectively. The PE- and PP-sealed Deodeok did not show significant differences in texture and moisture content for two days, and the moisture content was highest in the vacuum-packaged Deodeok during storage. In relation to the total viable cell and the coliform count, the vacuum-packaged Deodeok showed the lowest rate of increment during storage, followed by the others. Thus, the bubble-washed and vacuum-packaged minimally processed sliced Deodeok was found to have the best quality.

• Food Science and Preservation
• /
• v.10 no.2
• /
• pp.131-135
• /
• 2003

Bell pepper was packed with several plastic films, and investigated the quality Characteristics such as gas composition, weight loss, microbial load, soluble solid content, ascorbic acid and color during storage at 10$^{\circ}C$. Cast polypropylene (CPP), low density Polyethylene (LDPE), Polyolefin (MPD, PD961) and linear low density polyethylene (LLDPE) were used for this purpose. Oxygen concentration inside packages generally showed a 10∼14% after 1∼2 weeks, but package with CPP maintained above 15％ throughout the storage. Carbon dioxide concentration of CPP was above 2%, but other treatments showed below 2%. Weight loss of all treatments was below 3.0% after 5 weeks. Total microbial count showed a similar pattern compared to yeast and mold, and CPP maintained the highest microbial load after 3 weeks. Yellowness (b value) of bell pepper was generally increased throughout the storage, and MPD and PD961 were higher than other treatments.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.42 no.3
• /
• pp.352-356
• /
• 1997

In order to trace the survival route of weedy rice in Korean farmer's field, occurrence rate and position of weedy rice, number of weedy rice plants per $m^2$, in transplanted and direct seeded field were investigated. The highest occurrence rate of weedy rice in transplanted field was 5.5％. Number of weedy rice plants in direct seeded field was higher than that in transplanted field. In transplanted field, most of the weedy rice were grown within hills of cultivated rice and only a few was grown between hills of the cultivated rice, however in direct seeded field the number of weedy rice occurred between hills or rows of cultivated rice was higher than that occurred within hills or rows. Weedy rice occurrence rate in the field of .non-recommended rice variety was higher than that in the field of recommended variety. The main survival route of weedy rice in transplanted field was supposed to be mixture of weedy rice seeds with cultivated rice, and that in direct seeded field to be natural survival.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.38 no.5
• /
• pp.398-404
• /
• 1993

This study was conducted in order to obtain the information for yield improvement in saline paddy. Saline concentration, growth and yield of rice, being subjected to different flooding times and days to transplanting were investigated in saline paddy with 0.35 % and 0.5 % salt concentration. Saline concentration of soil was increased to 0.41 % just after rotary in the paddy with 0.35 % salinity, but decreased to 0.20 % after 3 to 4 times of flooding treatment. And also that of surface water was decreased from 0.2 % to 0.11 %. Saline concentration of soil in 5cm depth was decreased to 0.31 % by one time flooding and to 0.22% by 3～4 times flooding but salinity below 7cm depth showed slight decrease. Seedling death was exceeded 37 % when transplanted one day after rotary in the paddy with 0.35% salinity. Death ratio was decreased to 20% by three times flooding and transplanting six days after rotary. In paddy with 0.5 % salinity, death ratio was high but the tendency was very similar to 0.35 % field. In 0.35 % saline paddy field, yields were increased by 14 % by three times flooding and transplanting six days after rotary as compared to one time flooding and transplanting are day after rotary. Therefore, 3 to 4 times flooding and transplanting 5 to 6 days after rotary are desirable in high saline paddy.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.1 no.1
• /
• pp.29-37
• /
• 1995

The purpose of this study was to development the waxed rice straw pulp tray(WRSPT) which had low water sensitivity. The quality changes of mushrooms(Agaricus bisporus) packaged respectively in the WRSPT, non-treated rice straw pulp tray(NRSPT) and expanded polystyrene tray(EPST) were observed during storage. The weight losses of mushrooms in the WRSPTs were less than in the NRSPTs by maintaining below 3% at $0^{\circ}C$ and the applications of WRSPTs were more effective at $20^{\circ}C$. The weight increases of WRSPTs were more lowered than those of NRSPTs by marking below 15% during storage at $0^{\circ}C$. There were no significant differences in the Hunter L values and hardness values of mushrooms in the three types of trays at $0^{\circ}C$. The cap openings of mushrooms were more proceeded in NRSPTs than in WRSPTs and EPSTs at $20^{\circ}C$. As a result, it may be favorable to control excessive moisture absorption of the NRSPT mainly composed of cellulose pulp by introducing such chemical treatments as wax treatment.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.47 no.6
• /
• pp.422-426
• /
• 2002

In other to find out the basic information on cultivation and breeding for salt tolerance in rice, these studies were conducted at salinity paddy fields containing 0.2, 0.3, 0.4% of salt and normal paddy field using 6 Japonica type, 5 Tonsil type varieties and Annapurna. On these fields a series of investigation was made for the responses of rice growth and yield to salt content of saline sails. The heading dates of the rice cultivated at salinity 0.2, 0.3 and 0.4% were delayed compared by 2 or 3,5 or 8 and 10 or 13 days respectively in Japonica and Tonsil type varieties to those at the normal paddy fields. The culm length at salinity paddy fields decreased by 13-39% in Japonica type and 14-35% in Tongil type varieties. But the number of panicles per hill decreased by 16-40% in Japonica type and by 14-35% in Tongil type varieties. The number of grains per panicle in saline paddy fields decreased by 10 to 40% in all varieties, but the percent ripened grain decreased by 20-48% in Japonica type and by 19-51% in Tongil type varieties. 1000 grains weight was decreased by lower than 23% in all varieties, but yield was reduced to 20-62% in Japonica and 25-67% in Tongil type varieties.

• Food Science and Preservation
• /
• v.14 no.1
• /
• pp.42-46
• /
• 2007

To investigate the effects of hot water treatment and modified atmosphere packaging (MAP), compared with non-packaging, of 'Fuji' apples during 18 weeks of storage at $0^{\circ}C$, apple weight loss, firmness, titratable acidity, total ascorbic acid and sensory characteristics were measured After 18 week of storage, the weight loss of MAP-treated apples was 1%, while untreated controls lost 22% of weight Weight loss reduction film packaging was more effective than that afforded by hot water treatment. The firmness reductions in control apples, those receiving hot water treatment those receiving packaging only, and those receiving both hot water treatment and packaging, were 37%, 22%, 10% and 6%, respectively. The titratable acidity was 40% in control apples and respectively, 37%, 32% and 27% in the three groups mentioned above. The total ascorbic acid contentuntreated control apples decreased by 70% after 18 weeks of storage. The total ascorbic acid contentof apples receiving both hot water use of both packagingand hot water treatment to preserve 'Fuji' apple quality.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.25 no.3
• /
• pp.101-109
• /
• 2019

The effect of packaging and storage methods in enhancing the shelf life and improving the postharvest quality of the Korean head cabbage (Brassica rapa) used for wrapping vegetables was studied at 10℃. The wrapping cabbage was packed using four types of packaging and storage materials: (A) Perforated PP film; (B) Non-perforated PP film; (C) PVC film for wrapping; and (D) non-packaged as control. The quality parameters, such as fresh appearance, weight loss, hue angle, moisture content, hardness, and SSC of wrapping cabbage were investigated. The weight loss of wrapping cabbage showed a significant difference between the one packaged with film and the non-packaged as control. The general appearance of Korean cabbage stored at 10℃ was not significantly affected by the packaging treatments. However, Korean head cabbage packaged with perforated film tend to show a better external appearance compared with those exposed to the other packaging during three weeks of storage at 10℃. The inside appearance, hue angle, moisture content, hardness, and SSC, gradually decreased during the storage period. No remarkable change in the measured items were observed in Korean cabbage packaging methods. In this experiment, the Korean cabbage packaged inside a PP film with holes, and stored at 10℃ temperature had the most desirable outcome of extending the head cabbage's shelf life and appearance quality. Results suggest that perforated packaging treatment combined with low storage temperature could be an effective method in prolonging the shelf life of Korean cabbage for wrapping vegetable.