• Journal of Soil and Groundwater Environment
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• v.21 no.4
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• pp.1-9
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• 2016

Rehabilitation for low-yielding wells resulting in improvement on groundwater quantity and quality is considered to be the most economic and ecofriendly method against the increasing demand to groundwater due to frequent drought and the increase in numbers of agricultural complex for growing horticultural crops. This study suggests standard, stepwise diagnostic fuctions consisting of four steps (Basic inspection, Specific inspection, Rehabilitation, and Management) for an optimal management to the wells. Basic inspection can provide information on current groundwater quantity and quality compared with those on its initial stage. Specific-inspection based on hydrogeology can scientifically demonstrate causes of deterioration on groundwater quantity and quality. Results of specific inspection can suggest an optimal rehabilitation method to solve deteriorating problems including clogging and corrosion for the wells. After rehabiliating the wells, an assessment on groundwater quantity and quality would be conducted to identify the suitability of the applied method and improvement of the wells. A short-term, periodic management to the wells is considered as the key to save a public management budget. Suggested diagnostic functions can possibly induce sustainable supply of agricultural groundwater to the farm land and finally contribute the increase on rural household income.

• Environmental Analysis Health and Toxicology
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• v.29
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• pp.8.1-8.8
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• 2014

Objectives An ecofriendly alternative to chemical pesticides is bio-pesticides, which are derived from natural sources. The interest in bio-pesticides is based on the disadvantages associated with chemical pesticides. Methods We conducted acute toxicity assessments of camphor, a major component of bio-pesticides, by using Daphnia magna (D. magna) as well as assessed the morphological abnormalities that occurred in Danio rerio (D. rerio) embryos. Results The median effective concentration of camphor on D. magna after 48 hours was $395.0{\mu}M$, and the median lethal concentration on D. rerio embryos after 96 hours was $838.6{\mu}M$. The no observed effect concentration and predicted no effect concentration of camphor on D. magna, which was more sensitive than D. rerio, were calculated as $55.2{\mu}M$ and $3.95{\mu}M$, respectively. Morphological abnormalities in D. rerio embryos exposed to camphor increased over time. Coagulation, delayed hatching, yolk sac edema, pericardial edema, and pigmentation of embryos mainly appeared between 24 and 48 hours. Further, symptoms of scoliosis and head edema occurred after 72 hours. In addition, bent tails, ocular defects and collapsed symptoms of fertilized embryonic tissue were observed after 96 hours. Conclusions The camphor toxicity results suggest that continuous observations on the ecosystem are necessary to monitor toxicity in areas where biological pesticides containing camphor are sprayed.

• Journal of Microbiology and Biotechnology
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• v.30 no.8
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• pp.1156-1168
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• 2020

Drought stress is threatening the growth and productivity of many economical crops. Therefore, it is necessary to establish innovative and efficient approaches for improving crop growth and productivity. Here we investigated the potentials of the cell-free extract of Actinobacteria (Ac) isolated from a semi-arid habitat (Al-Jouf region, Saudi Arabia) to recover the reduction in maize growth and improve the physiological stress tolerance induced by drought. Three Ac isolates were screened for production of secondary metabolites, antioxidant and antimicrobial activities. The isolate Ac3 revealed the highest levels of flavonoids, antioxidant and antimicrobial activities in addition to having abilities to produce siderophores and phytohormones. Based on seed germination experiment, the selected bioactive fraction of Ac3 cell-free extract (F2.7, containing mainly isoquercetin), increased the growth and photosynthesis rate under drought stress. Moreover, F2.7 application significantly alleviated drought stress-induced increases in H₂O₂, lipid peroxidation (MDA) and protein oxidation (protein carbonyls). It also increased total antioxidant power and molecular antioxidant levels (total ascorbate, glutathione and tocopherols). F2.7 improved the primary metabolism of stressed maize plants; for example, it increased in several individuals of soluble carbohydrates, organic acids, amino acids, and fatty acids. Interestingly, to reduce stress impact, F2.7 accumulated some compatible solutes including total soluble sugars, sucrose and proline. Hence, this comprehensive assessment recommends the potentials of actinobacterial cell-free extract as an alternative ecofriendly approach to improve crop growth and quality under water deficit conditions.

• Journal of Microbiology and Biotechnology
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• v.30 no.10
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• pp.1510-1515
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• 2020

Trimethylamine (TMA) is a well-known off-odor compound in fish and fishery products and is a metabolic product of trimethylamine N-oxide (TMAO) generated by the enzymatic action of microorganisms. The off-odor is a factor that can debase the value of fish and fishery products. The present study aimed to remove TMA using lactic acid bacteria (LAB). A total of fifteen isolates exhibiting the TMA reduction efficacy were isolated from Korean traditional fermented foods. Among these isolates, five LAB isolates (Lactobacillus plantarum SKD 1 and 4; Lactobacillus paraplantarum SKD 15; Pediococcus stilesii SKD 11; P. pentosaceus SKD 14) were selected based on their high TMA reduction efficacy. In situ reduction of TMA efficacy by the LAB cell-free supernatant was evaluated using a spoiled fish sample. The results showed effective TMA reduction by our selected strains: SKD1 (45%), SKD4 (62%), SKD11 (60%), SKD14 (59%), and SKD15 (52%), respectively. This is the first study on TMA reduction by the metabolic activity of LAB and in situ reduction of TMA using cell-free supernatant of LAB. The present finding suggests an economically useful and ecofriendly approach to the reduction of TMA.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.1064-1067
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• 2012

Recently, there is a growing interest in vegetable oils, cheap and abundant renewable natural resources. Vegetable oils can be used as raw materials for ecofriendly biodegradable polymer materials. In this study, poly(${\beta}$-amino esters) were synthesized by polymerization reaction of acrylated epoxidized soybean oil (AESO) and 2-aminoethanol. Various polymer films were prepared by changing the molar ratio of AESO to 2-aminoethanol. The formation of C-N bonds in poly(${\beta}$-amino ester) was confirmed using FT-IR. Gel contents higher than 98% confirmed the synthesis of crosslinked polymer networks. Tensile strengths and elongation at breaks of polymer films ranged from 0.3 to 1.3 MPa and 32 to 55%, respectively. Polymer films degraded 2 to 7% of the initial weight in 35 days in phosphate buffer solution (pH 7.2) containing lipase enzyme.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.3
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• pp.276-280
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• 2017

In this study, we investigated the effect of sterilization and the neutralization of treated ballast water using seawater electrolysis. The electrolysis apparatus has a cation-selective membrane for passing the cation and a titanium electrode in each cell. We examined the sterilization effect after an incubation period of 24 hr. The oxidation reaction during electrolysis caused, the solution to become strongly acidic due to the generation of a hydroxyl group, and the oxidation reduction potentials(ORP) was increased to 800 - 1200mV. After the reduction reaction, the solution became alkaline(pH 9 - 12), and ORP was decreased to - 900 - - 750 mV. It might be possible to control the pH of ballast water through electrolysis. In addition, we demonstrated the effects of sterilization of ballast water containing generated hypochlorous acid using electrolysis under high ORP condition.

• International Journal of Industrial Entomology and Biomaterials
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• v.40 no.2
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• pp.41-50
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• 2020

Vermicompost, manure, compost and organic fertilization are ecofriendly. Nowadays, many products resulted from sericulture consumed by humans such as mulberry leaves, fruits, mulberry tea, silk and natural silk cosmetics. Soil applications of three treatments with vermicompost (0.5, 1 and 2 tons per 0.42 hectare) and recommended rate of mineral fertilizers of nitrogen phosphorus potassium were used for investigation. Impact of fertilization on mulberry plant traits of moisture, number of shoots/tree, total shoots length/tree, number of leaves/shoot, number of leaves/ (100g), leaf yield/tree and leaf yield of fadden/season were recorded. In addition the effect of fertilization on larval and cocoon characters of young instar duration, fifth instar duration, total larval duration, larval mortality percentage, weight of third instar larvae, weight of fourth instar larvae, weight of fifth instar larvae, fresh cocoon weight, fresh shell weight, pupae weight, cocoon shell ratio, silk productivity, cocooning percentage, pupation ratio, number of cocoons/ liter, crop cocoons by number, crop cocoons by weight, fecundity and fertility. Using vermicompost treatment was enhancing plant characters. Treatments of V₃, V₂ and V₁ were shortage young, fifth and larvae durations. Mostly feeding silkworm during the whole larval duration on treated mulberry leaves with vermicompost improving the traits average. Using vermicompost for fertilization by rate of V₃ and V₂ is better than others for cocoon characters for females and males.V₃ and V₂ of vermicompost per 0.42 hectare is recommended for rearing mulberry silkworm instead of mineral fertilization.

• Journal of Powder Materials
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• v.25 no.1
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• pp.30-35
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• 2018

The friction characteristics of Al-Fe alloy powders are investigated in order to develop an eco-friendly friction material to replace Cu fiber, a constituent of brake-pad friction materials. Irregularly shaped Al-Fe alloy powders, prepared by gas atomization, are more uniformly dispersed than conventional Cu fiber on the brake pad matrix. The wear rate of the friction material using Al-8Fe alloy powder is lower than that of the Cu fiber material. The change in friction coefficient according to the friction lap times is 7.2% for the Cu fiber, but within 3.8% for the Al-Fe alloy material, which also shows excellent judder characteristics. The Al-Fe alloy powders are uniformly distributed in the brake pad matrix and oxide films of Al and Fe are homogeneously formed at the friction interface between the disc and pad, thus exhibiting excellent friction and lubrication characteristics. The brake pad containing Al-Fe powders avoids contamination by Cu dust, which is generated during braking, by replacing the Cu fiber while maintaining the friction and lubrication performance.

• Polymer(Korea)
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• v.38 no.3
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• pp.327-332
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• 2014

Polymer/wood flour composites are recently attracting a lot of interest because they are economic and ecofriendly. In this study, the effects of wood flour size on the thermal and mechanical properties of a polypropylene/wood flour composite were investigated. Mechanical properties of the composite samples prepared by melt-mixing and compression molding were tested by UTM and an izod impact tester, and thermal properties of them were measured by TGA, DMA, DSC and TMA. The best coupling agent was selected by testing three kinds of maleic anhydride modified polypropylene coupling agents, and under the same condition, the effects of wood flour size on the physical properties of the composite were investigated. According to the test results for four different wood flour sizes of 600, 250, 180 and $150{\mu}m$, flexural strength, flexural modulus, crystallinity and water-resistivity of the composite increased with decreasing wood flour size.

• Textile Coloration and Finishing
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• v.32 no.1
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• pp.38-43
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• 2020

To overcome the harmful effects caused by conventional oxidative hair dyes, natural colorants becomes more popular in the hair dyeing. By extracting Sagassum fusiforme powders with aqueous alkaline solution as a solvent at 130℃ for 60 minutes, a fucoxanthin concentration of up to 216㎍/ml can be obtained. UV/Vis analysis was used to prove the presence of fucoxanthin in the extract powder. A K/S value of 23.8 can be obtained when wool fabrics were dyed with the extract at 120℃ for 60 minutes under pH 2. The color fastness properties of the dyed wool fabrics were very good as indicated by rating 4 for laundering(color change), rating 3 or higher for rubbing, and rating 5 for light irradiation. The dyed wool fabric was found to have antimicrobial activity against Staphylococcus aureus. The antioxidant and antimicrobial activity of the Sagassum fusiforme extract can be an effective functional hair colorant. Hair dyeing with the extract formulation at 45℃ for 40 minutes under pH 5 accomplished a K/S value of 8.9. The color fastness of the dyed hair showed rating 3 against light irradiation, which increased to rating 5 with after-mordanting of tannin acid.