• Ocean and Polar Research
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• v.33 no.2
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• pp.99-111
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• 2011

To estimate the effects of limitation nutrients for phytoplankton growth and its influences on short-term variations of a winter phytoplankton community structure, we investigated the abiotic and biotic factors of surface and bottom waters at 20 stations of inner and offshore areas from 6 to 7 February in Gwangyang Bay, Korea. Also, several algal bio-assay studies were conducted to identify any additional nutrient effects on phytoplankton assemblage using surface water for the assay. The dominant species in the bay was diatom Skeletonema costatum, which occupied more than 70% of total species in most stations (St.1-16) of the inner bay. According to a cluster and multidimensional scaling (MDS) analysis based on phytoplankton community data from each station, the bay was divided into three groups. The first group included stations from the south-western parts of Myodo lsland, which can be characterized as a semien-closed eutrophic area with high phytoplankton abundance. The second group included most stations from the north-eastern part of Myodo lsland, influenced indirectly by surface water currents from offshore of the bay. The standing phytoplankton crops were lower than those of the first group. The other cluster was restricted to samples collected from offshore of the bay. In the bay, silicon (Si) and phosphorus (P) were not a major limiting factor for phytoplankton production. However, since the DIN: DIP and DSi: DIN ratios clearly demonstrated that there were potential stoichiometric N limitations, nitrogen (N) was considered as a limiting factor. Based on the algal bio-assay, in vivo fluorescence values in N (+) added experiments were higher compared to control and P added experiments. Our results suggested that nitrogen may act as one of the most important factors in controlling primary production during winter in Gwangyang Bay.

• KSBB Journal
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• v.14 no.4
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• pp.503-510
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• 1999

In order to analyze nutritional factors affecting in situ bioremediation of diesel degradation and cell viability were studied by varying nutritional conditions. In column experiments packed with diesel-contaminated soil, nitrogen was found to be the major limiting nutrient. When nitrogen was added to soil at four different levels of C : N (100 : 5, 100 : 10, 100 : 15, and 100 : 20 mg N/kg dry soil), the greatest simulation of microbial activity occurred at the lowest, rather than the highest nitrogen addition. However, no significant effects was observed when phosphorus and air were added. No matter how the incubation mode varied, less than 50% of the diesel was remained after 7 days of treatment, presumably because the residual hydrocarbons were adsorbed on soil particles, adsorption

• Journal of the Korean Society of Food Science and Nutrition
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• v.13 no.1
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• pp.117-126
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• 1984

Aflatoxins are toxic and carcinogenic secondary metabolites which are produced by trains of A. flavus and A. parasiticus during their growth on foods and feedstuffs. Aflatoxins are a group of closely related heterocyclic compounds of which $B_1$, $B_2$, and $G_2$ are the major members. Aflatoxins are synthesized via a polyketide pathway in which the general steps are acetate, an-thraquinones, xanthone and aflatoxins. Aflatoxin formation is favored by high moisture or high $a_w$(0.95${\sim}$0.99). The limiting $a_w$ for aflatoxin production on agricultural commodities is 0.83. Optimum temperature for aflatoxin production by the molds is $25{\sim}30^{\circ}C$ and the incubation time for the maximum production of the toxin is 7${\sim}$15 days. The limiting temperatures for aflatoxin production are ${\leq}7.5^{\circ}C\;and\;\geq40^{\circ}C$. Cycling temperatures may or may not stimulate aflatoxin production depending on the amplitude of cycling, substrate and strains of molds. Aflatoxin pro-ducing molds are aerobic organisms and thus have a requirement for oxygen. A decreasing $O_2$ concentration and/or increasing concentrations of $CO_2$ or $N_2$ depress the mold growth and aflatoxin formation. A. flavus grows competitively or associatively in the presence of other microorganisms and occasionally loses the competition with other microorganisms. Some lactic acid bacteria have been shown to reduce growth and aflatoxin production by A. parasiticus. Carbon source is the most important nutritional factors affecting aflatoxin formation by the molds. Sucrose, fructose and glucose are the most favorable carbon sources. Food substrates of plant derived products which have high carbohydrate content such as agricultural commodities and their products are most vulnerable to contamination by aflatoxins.

• Microbiology and Biotechnology Letters
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• v.35 no.4
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• pp.261-271
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• 2007

Phytoremediation is an economic and environmentally friendly technique to remediate contaminated-soil. In this study, the effects of plants, rhizobacteria and physicochemical factors on phytoremediation have been reviewed. For successful phytoremediation, the selection of plants is primarily important. To remediate soil contaminated with petroleum hydrocarbon, raygrass (Lolium multiflorum lam), white mustard, vetch (Vicia villosa), tall fescue (Festuca arundinacea), legumes, poplar, and Pine (Pinus densiflora) were mainly applied, and the removal efficiency of petroleum hydrocarbon were ranged 68 to 99%. Corn (Zea mays), raygrass (Lolium multiflorum lam), vetch (Vicia villosa), mustard, clover (Trifolium repens), and tall fescue (Festuca arundinacea) were used for the removal of polycyclic aromatic hydrocarbon, and their removal efficiencies were 50-98%. Rhizobacteria play significant roles for phytoremediation because they can directly participate in the degradation of contaminant as well as promoting plants growth. The following rhizobacteria were preferred for phytoremediation: Azospirillum lipoferum, Enterobactor cloacae, Azospirillum brasilense, Pseudomonas putida, Burkholderia xenovorans, Comamonas testosterone, Pseudomonas gladioli, Azotobacter chroococcum, Bacillus megaterium, and Bacillus subtilis. Pysicochemical factors such as pH, temperature, nutrient, electron acceptor, water content, organic content, type of contaminants are consequential limiting factors for phytoremediation.

• Journal of Distribution Science
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• v.12 no.7
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• pp.77-88
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• 2014

Purpose - Based on the existing retail policy literature, this study aims to compare Korea with foreign countries, to propose better ideas for the Korean retail market. Research design, data, and methodology - It is necessary to analyze the existing retail regulations after categorizing them into several groups, depending on why governments have regulated retailers and the background for the retail policy. Results - Given that Korean retail regulations have focused on protecting conventional markets, comparing the retail policy objectives of South Korea and foreign countries is difficult. Conclusions - It is necessary examine how to protect independent stores, irrespective of store locations across the country. Rather than limiting the distance between traditional markets and the projected locations suggested by large retailers, various factors such as store size limit, opening and closing times, below-cost selling, land use planning, and competition tests are needed to protect small stores. Further, centralized authority for store operations should be delegated to local governments, to tackle the aggressive expansion of retail giants. To protect independent stores, political background is among the most important factors.

• Steel and Composite Structures
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• v.14 no.3
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• pp.243-265
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• 2013

Distortional and local buckling are important factors that influences the bearing capacity of steel-concrete composite box-beam. Through theoretical analysis of distortional buckling forms, a stability analysis calculation model of composite box beam considering rotation of steel beam top flange is presented. The critical bending moment calculation formula of distortional buckling is established. In addition, mechanical behaviors of a steel beam web in the negative moment zone subjected separately to bending stress, shear stress and combined stress are investigated. Elastic buckling factors of steel web under different stress conditions are calculated. On the basis of local buckling analysis results, a limiting value for height-to thickness ratio of a steel web in the elastic stage is proposed. Numerical examples are presented to verify the proposed models.

• Solar Energy
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• v.9 no.2
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• pp.58-68
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• 1989

This paper describes an experimental study that was performed to determine the limiting factors on the power output in the closed cycle Electro-Hydro-Dynamic generator of small capacity. A corona discharge for producing unipolar charged particles used as the charging method. The experiment demonstrated that the corona method of charging was an efficient and effective means of producing unipolar charged particles. Four factors having an effect on the power output characteristics of EHD generator are discussed and examined experimentally, using methyl alcohol and kerosene as working fluides; a. The conversion length between attractor and collector. b. The corona current of Emitter. c. The flow velocity of working fluids. d. Load resistance. This results are as follows; 1) There in a critical value in conversion length for its maximum power output. 2) Power output increases almost linearly with corona current and flow velocity. 3) There is the critical value of load resistance producing a maximum power output. 4) Kerosene is known better working fluid than Methyl alcohol in this EHD generator.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.418-421
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• 1988

Holographic interferometry is applied in dental research to study the motion of teeth and the deformation of the associated facial structure. We consider double exposure holographic interferometry which has limiting factors such as the stability of fringes, the recording time, the amount of exposure, the localization of fringes and sensitivity. These factors are taken into account to make interferogram. The resulting interferogram gives fringe pattern which is analyzed qualitatively to determine the relative rotation and the deformation of the facial structure.

• Structural Engineering and Mechanics
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• v.9 no.6
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• pp.589-600
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• 2000

This paper attempts to provide a theoretical basis for the design of high-strength concrete columns in terms of the spacing of lateral reinforcement. In order to achieve this, important concepts had to be addressed such as the choice of a measure of ductile behaviour and a realistic high-strength concrete stress-strain model, as well as limiting factors such as longitudinal steel buckling and lateral steel fracture. A design method incorporating above factors are suggested in the paper. It is shown that both buckling of longitudinal steel and hoop fracture will not demand a reduction in spacing of lateral ties with increase in compressive strength of concrete.

• 한국지구물리탐사학회:학술대회논문집
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• 2001.09a
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• pp.90-93
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• 2001

Various soil remedial technologies have been developed and main effort has been to overcome the limiting factors. Major factors were the geophysical characteristics, especially hydraulic, electrical, and heat conductivities. In this paper, I have reviewed the remedial technologies depending on those. Only with comprehensive understanding and information on those characteristics, selection of the best remedial method can be possible.