• The Pure and Applied Mathematics
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• v.18 no.4
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• pp.361-368
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• 2011

In this paper, we construct a cover ($\mathcal{L}(X)$, $c_X$) of a space X such that for any cloz-cover (Y, f) of X, there is a covering map g : $Y{\longrightarrow}\mathcal{L}(X)$ with $c_X{\circ}g=f$. Using this, we show that every Tychonoff space X has a minimal cloz-cover ($E_{cc}(X)$, $z_X$) and that for a strongly zero-dimensional space X, ${\beta}E_{cc}(X)=E_{cc}({\beta}X)$ if and only if $E_{cc}(X)$ is $z^{\sharp}$-embedded in $E_{cc}({\beta}X)$.

• Korean Journal of Organic Agriculture
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• v.20 no.2
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• pp.173-183
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• 2012

This study was conducted to select promising green manure crops, providing sufficient amount of nutrients for satisfying fruit tree growth, with the overwintering cover crops grown in organic orchards in 2009. The cover covers were investigated in 13 organic orchards in Chonnam province in April and June. The dry matter in cover crops observed in April and June was the highest for Lolium multiflorum Lam. and Bromus japonicus Thunb., respectively. Total N and K production in April was the highest for Lolium multiflorum Lam, Vicia hirsuta (L.) S. F. Gray and Vicia angustifolia var. segetilis (Thuill.) K. Koch., respectively, with Bromus japonicus Thunb. in June. This study showed that the leguminous crops, Vicia hirsuta (L.) and Vicia angustifolia, would be the prospective cover covers as the both crops provided sufficient amount of N and $K_2O$ into the soil. Amount of $P_2O_5$ producing from all cover crops provided less than nutrient levels than those of recommended nutrient requirement for satisfying 10- to 15-year-old fruit tree growth.

• Journal of Environmental Science International
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• v.27 no.5
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• pp.291-297
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• 2018

Vertical farming systems offer many advantages in urban spaces. They have also been proposed as an engineering solution to increase the productivity per unit area of cultivated land by extending crop production in the vertical dimension. However, soil water retention is a major constraint affecting the plant environment. This study analyzed the effects of growth environment of Tropaeolum majus and Fragaria spp., on the vertical farming system, by using four different types of cover material types including sphagnum moss (Control), a shading net (S.N.), multi-layered fabric (M.L.F.), and non-woven fabric (N.W.F.). The volumetric soil moisture contents and plant characteristics were investigated from May to September 2014. Plant materials were individually cultivated in hanging baskets measuring $30{\times}17{\times}17cm$, filled with a mixture of soil and perlite, and placed at 1.5m height. Each treatment was performed in quadruplicate and consisted of five plants, amounting to a total of 20 plants. The analysis indicated that different covers were associated with multiple functions and soil water retention improvements may have a positive impact on the vertical farming system. The difference in soil water retention increased in the following order: M.L.F. > Control > N.W.F. > S.N.. Furthermore, the differences in plant height and survival rate increased in the following order: M.L.F. > Control > N.W.F. > S.N. Therefore, M.L.F yielded satisfactory good response for the vertical farming system of cover materials. Our results clearly demonstrate that vertical spaces represent an attractive alternative to urban farming and suggest that further increases in yield may be achieved via different cover materials in vertical farming using hanging baskets.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1018-1031
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• 2010

In order to investigate the applicability and suitability of the industrial by-products to landfill final cover, field pilot-scale lysimeter experiments were carried out. The mixture of loamy soil, bottom ash, and construction waste was placed as a cover material in lysimeter($2m{\times}6m{\times}1.2m$) which were constructed with cement brick, and then, volumetric water contents, pF value, and the quantity of runoff and seepage of treatment boxes filled with the mixture of loamy soil and the industrial by-products were monitored from July, 2007 to February, 2008. Among the cases tested, consequently, the case containing the mixture of bottom ash and loamy soil was most effective in engineering and hydrological properties and water retention ability.

• The Pure and Applied Mathematics
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• v.20 no.2
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• pp.103-108
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• 2013

Observing that for any space X, there is a Wallman sublattice $\mathfrak{A}_X$ and that QFX is homeomorphic to a subspace $X_q$ of the Wallman cover $\mathfrak{L}(\mathfrak{A}_X)$ of $\mathfrak{A}_X$, we show that ${\beta}QFX$ and $\mathfrak{L}(\mathfrak{A}_X)$ are homeomorphic.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1655-1665
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• 2008

In order to investigate the applicability and suitability of the industrial by-products to landfill final cover, field pilot-scale lysimeter experiments were carried out. The mixture of loamy soil, bottom ash, and construction waste was placed as a cover material in lysimeter($2m{\times}6m{\times}1.2m$) which were constructed with cement brick, and then, volumetric water contents, pF value, and the quantity of runoff and seepage of treatment boxes filled with the mixture of loamy soil and the industrial by-products were monitored from July, 2007 to February, 2008. As a result, the case containing the mixture of bottom ash and loamy soil was most effective in engineering and hydrological properties and water retention ability.

• Bulletin of the Korean Mathematical Society
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• v.30 no.1
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• pp.117-124
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• 1993

In this paper, we introduce a concept of quasi $O_{z}$ -spaces which generalizes that of $O_{z}$ -spaces. Indeed, a completely regular space X is a quasi $O_{z}$ -space if for any regular closed set A in X, there is a zero-set Z in X with A = c $l_{x}$ (in $t_{x}$ (Z)). We then show that X is a quasi $O_{z}$ -space iff every open subset of X is $Z^{#}$-embedded and that X is a quasi $O_{z}$ -spaces are left fitting with respect to covering maps. Observing that a quasi $O_{z}$ -space is an extremally disconnected iff it is a cloz-space, the minimal extremally disconnected cover, basically disconnected cover, quasi F-cover, and cloz-cover of a quasi $O_{z}$ -space X are all equivalent. Finally it is shown that a compactification Y of a quasi $O_{z}$ -space X is again a quasi $O_{z}$ -space iff X is $Z^{#}$-embedded in Y. For the terminology, we refer to [6].[6].

• Journal of the Korean Geotechnical Society
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• v.26 no.7
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• pp.81-91
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• 2010

In order to investigate the applicability and suitability of the coal ash (bottom ash) to landfill final cover, field pilot-scale lysimeter experiments were carried out. The mixture of loamy soil, bottom ash, and construction waste was placed as a cover material in lysimeter ($2m{\times}6m{\times}1.2m$) which were constructed with cement brick, and then volumetric water contents, pF value, and the quantity of runoff and seepage of treatment boxes filled with the mixture of loamy soil and the industrial by-products were monitored from July, 2007 to february, 2008. Among the cases tested, consequently, the case containing the mixture of bottom ash and loamy soil was most effective in plant growth and water retention ability.

• Asian Journal of Turfgrass Science
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• v.7 no.1
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• pp.19-30
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• 1993

Experiments were conducted to investigate propagation, shade tolerance, cold resistance and growth rate of evergreen ground cover plants ; Vinca minor K , Ajuga reptans L., Ophiopogon japonicus ker. f nanus hort , and Hedera helix.. The results were as follows : 1.It is convenient to use the growing case for rice seed to grow and transplant Vinca minor seed-ling. The most proper density of transplanting Vinea was 180 plants per 1m$^2$. At the end of growing season, the coverage came up to 90% The rooting ability of Hedera helix was best to cut from April to May (temperature 15~23˚C). The seedling length of Parthenocissus quinguefohlia were irregular and ranged from 5 cm of 200cm. 2. Ajuga reptans L., Ophiopogon j. and Vinca minor L. grew better under 50% light intensity than full sunlight. Particularly, under full sunlight and aestival high temperature, there were a few withering plants in Ajuga reptans L. , and V Vilica minor L. 3. Of Vinca minor K., Ajuga reptans L. , Ophiopogon japonicus ker. f. nanus hort. and Hedera helix. acclimatized in open field, where temperature was from -7~8˚C. There were few plants had damage in low temperature incubator to -16˚C after field acclimatization. 4.Tendrils of Parthenocissus quinguefolia strongly clung to the wire netting stone fence but intruded into the gap and cranny of the precast concrete fence and so clung to, so that it needed to install the bending net on the precast concrete fence.

• Korean Journal of Agricultural Science
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• v.12 no.1
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• pp.108-117
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• 1985

The process of conveying of soil with the open auger to cover the seed completly with less power was reviewed by theoretical analysis. The power efficiency, the reasonable range of RPM of the open auger and the velocity of soil conveying to the direction of the shaft are examined to establish the extent of characteristics of the open auger performance. The results of theoretical analysis and application of similitude are as follows: 1. It is possible to predict the power efficiency by the following equation; ${\eta}_p={\frac{P_n}{P_g}}=({\frac{{\omega}_s}{{\omega}_a}}){\cdot}tan{\gamma}{\frac{mg}{(F_mcos{\alpha}+F_scos{\gamma})}}$ 2. The reasonable range of the revolutions per minute of the open auger was presented as follow to cover completely with less power ; $$\frac{4d(L_a-L_i){\cdot}V_w}{{\pi}(D_o^2-D_s^2){\cdot}r{\cdot}{\frac{{\omega}_s}{{\omega}_a}}{\cdot}tan{\gamma}}{{\leq_-}}{\omega}_a{{\leq_-}}({\frac{{\omega}_a}{{\omega}_s}}){\sqrt{\frac{g}{r}}}$$ 3. The velocity of soil conveying to the direction of the auger shaft may be calculated by the equation; $V_h=({\frac{{\omega}_s}{{\omega}_s}})V_a{\cdot}tan{\gamma}$ 4. The factor of RPM was more important than other factors on the power efficiency.