• Weed & Turfgrass Science
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• v.5 no.4
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• pp.236-240
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• 2016

Weeding measures is an important issue for cereal crop because weed is superior to crops in early growth stage and there are not many herbicides applicable to cereal crop. Since the concern about well-being and eco-environmental products are increasing, cultivation with polyvinyl chloride (PVC) is needed. Five treatments included as weed-free, control (not remove weed) and covering with polyvinyl chloride removed 20, 30, 40 DAS (day after seeding). At removing PVC, plant height did not differ depending on the growth stage. However, weed-free plot by weed competition were somewhat short. And, removing PVC accelerated the earlier by 2-3 day than weed-free plot. Soil moisture which removed from the control was higher than 20, 30, 40 DAS and weed-free, and it was kept low by evaporation. The chlorophyll meter of weed-free plot was 34.3, 30 DAS was 40.6 at heading time. Weed-free showed that increased in weed population $300.8g\;m^{-2}$. Weed control value of 20 DAS, 30 DAS, 40 DAS were 86.5%, 84.0% and 74.8%, respectively. In 30 DAS, yield of foxtail millet according to treatment of removing PVC were $355kg\;10a^{-1}$. At weed competition early in 30 DAS, the removing PVC was good for control. Thus, 30 DAS was judged to be suitable.

• Journal of the Korean Geotechnical Society
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• v.34 no.10
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• pp.5-16
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• 2018

The ever-increasing amount of waste vinyl is causing big environmental problems. In particular, those from farming industry are sometimes left on site or even illegally reclaimed due to the lack of environmental concerns and capacity for collection, which worsens the situation. It is, therefore, believed that the recycling of waste vinyl is the most ideal solution in the viewpoint of environmental preservation. In this context, the potential of vinyl strip as a ground reinforcing material is investigated to expand the application of waste vinyl recycling. In this study, a series of uniaxial compression tests and resonant column tests were performed for sand specimens reinforced with vinyl strips and cement to investigate their reinforcing effects on static and dynamic behaviors. The changes in the uniaxial compressive strength (UCS), the shear modulus and the damping ratio according to the mixing ratio of vinyl strips and cements were analysed for sand specimens, having 40% and 60% relative densities, under various mixing conditions. As a result, both the static and dynamic reinforcing effects of vinyl strip-cement mixture were confirmed and the optimum mixing ratio was proposed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.4
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• pp.315-319
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• 1990

In order to determine the optimum sowing date of Cassia tora L., ecological characters, components and yield were investigated under vinyl-mulching and non-mulching condition. Emergence date and maturation date of vinyl-mulching condition were earlier than those of non-mulching condition. especially with maturation date being about 30 days earlier, Under vinyl-mulching condition, length of stem and pod were longer, number of branches, pods and seeds per plant were increased, stem diameter was thicker, and weight of 1000 grains was heavier. Seed yield per 10a under vinyl-mulching was twice as high as that of non-nulching condition. As sowing date was delayed, the maturation date was progressively delayed. At sowing date of April 10, plants showed the longest in length of stem and pod, the largest in number of pods per plant and number of grains per pod, and the highest in weight of 1000 grains and seed yield. Judging from the results, optimum sowing of Cassia tora L. appeared to be April 10.

• The Korean Journal of Mycology
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• v.27 no.2 s.89
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• pp.107-111
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• 1999

Vinyl mulching was used on Oyster mushroom beds in an attempt to control bacterial diseases of Pleurotus ostreatus. Beds were covered with perforated, transparent vinyl sheets (0.03 mm thick, 180 cm wide); holes (10 cm diameter) were 10 cm apart. There were $25\;holes/m^2$. Vinyl mulching made management of the crop easier. Discrete mushroom flushes formed with high quality bunches of mushrooms formed through the holes; this made picking quicker and made more efficient use of labor. Total yield of mushrooms increased by 5.7% to $10.8\;kg/m^2$. Mushroom mycelium under vinyl remained healthy and white; whereas mycelium grown using conventional methods changed from white to yellow-brown during the cropping cycle. The mean weight of a mushroom bunch from vinyl mulched beds was 283 g (33 fruitbodies) compared to 117 g (15 fruitbodies) obtained using conventional growing methods.

• Elastomers and Composites
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• v.34 no.4
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• pp.360-365
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• 1999

In this study, the blends of acrylic quaternary polymer (PEBEV) which was co- polymerized from 2-ethylhexyl acrylate (2-EHA), n-butyl acrylate (BA) and ethyl acrylate (EA), vinyl acetate (VAc), and poly(vinyl chloride-co-vinyl propionate) (PVCVP) were prepared by solution blending. Pressure sensitive adhesive (PSA) properties of PEBEV/PVCVP blends were compared with those of PEBEV/poly(vinyl chloride-co-vinyl acetate) (PVCVAc) blends. Compatibility of PEBEV/PVCVP was better than that of PEBEV/PVCVAc. Tackiness of both blend systems were similar, but holding power began to decrease at 15wt% or higher PVCVAc contents in PEBEV/PVCVAc blends. On the other hands, holding power of PEBEV/PVCVP increased as the contents of PVCVP increased. Failure modes of the blends were adhesive failure except 5wt% of PVCVP was blended.

• Clean Technology
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• v.16 no.2
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• pp.73-79
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• 2010

Vinyl acetate(VAc) was dispersion-polymerized using supercritical carbon dioxide that has many environmental advantages. To get poly(vinyl acetate) (PVAc) of larger molecular weights from conventional emulsion polymerization, VAc was polymerized at temperatures between 333.15 and 343.15 K and pressures between 20 and 40 MPa with initiator (0.5 ~ 5% of monomer) and silicone-based stabilizer (1 ~ 10% of monomer) for 2 ~ 50 hr. The resulting PVAc was analyzed to see the variations in the yield and the molecular weight. The final product of this research, PVA (poly(vinyl alcohol)), was prepared from PVAc by saponification. The effect of saponification conditions on the yield and the molecular weight of polymer were also studied.

• Proceedings of the Korean Fiber Society Conference
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• 1993.06a
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• pp.62-62
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• 1993

• Proceedings of the Korean Fiber Society Conference
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• 1994.10a
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• pp.143-143
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• 1994

• Proceedings of the Korean Fiber Society Conference
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• 1996.04a
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• pp.53-56
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• 1996

• The monthly packaging world
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• s.309
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• pp.68-73
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• 2019