• Journal of Korean Society for Atmospheric Environment
• /
• v.24 no.1
• /
• pp.55-62
• /
• 2008

This study is aimed at substantially reducing the particulate matter (dust) emission during the combustion of heavy fuel in boilers by addition of combustion improver. The combustion improver used were the oil-soluble organometallic compounds that were found to be more effective than the dispersing agents that are generally used for reducing the particulate emission. The dust reduction effect was found to depend on the active materials (metals) as well as on the organic ligand part of organometallic compounds. Acetylacetonoate and naphthenate of Fe and Ca were found to be most effective for dust reduction. Addition of Fe and Ca organometallic compounds as combustion improver in concentration of 30 ppm (metal basis) to heavy fuel oil, caused dust reduction by 50 wt% to 80 wt%.

• Advances in environmental research
• /
• v.2 no.2
• /
• pp.131-141
• /
• 2013

Agricultural practice and improper waste disposal in developing regions have resulted in environmental degradation in land and waters, for which low-cost, proven solutions are needed. We demonstrate in the laboratory the applications of composting and trickling filter techniques to treat olive mill wastes that can be implemented in the West Bank and other regions of the world. To a pomace waste sample from a California mill, we amended with saw dust (wood carbon source) and baking soda ($NaHCO_3$ alkalinity) at weight ratios of waste/wood/$NaHCO_3$ at 70:27:1 and composted it for periods of 11 and 48 days; the compost was used as an additive to potting soil for transplanting. The pomace sample was also blended into slurry and introduced to a water-circulating pond and trickling filter system (P/TF) to examine any inhibitive effect of the pomace on biological removal of the organic waste. The results showed the compost-amended potting soil supported plant growth without noticeable stress over 34 days and the P/TF system removed BOD and COD by >90% from the waste liquid within 2 days, with a first-order rate constant of 1.9 $d^{-1}$ in the pond. An onsite treatment design is proposed that promises implementation for agricultural waste disposal in developing regions.

• Journal of Microbiology and Biotechnology
• /
• v.29 no.7
• /
• pp.1071-1077
• /
• 2019

Natural gamma-decalactone (GDL) produced by biotransformation is an essential food additive with a peach-like aroma. However, the difficulty of effectively controlling the concentration of the substrate ricinoleic acid (RA) in water limits the biotransformation productivity, which is a bottleneck for industrialization. In this study, expanded vermiculite (E-V) was utilized as a carrier of RA to increase its distribution in the medium. E-V and three commonly used organic compounds were compared with respect to their effects on the biotransformation process, and the mechanism was revealed. Scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis indicated that RA was physically adsorbed onto the surface of and inside E-V instead of undergoing a chemical reaction, which increased the opportunity for interactions between microorganisms and the substrate. The highest concentration of GDL obtained in the medium with E-V was 6.2 g/l, which was 50% higher than that in the reference sample. In addition, the presence of E-V had no negative effect on the viability of the microorganisms. This study provides a new method for producing natural GDL through biotransformation on an industrial scale.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.41 no.4
• /
• pp.302-307
• /
• 2021

In the current study, lactic lactic acid bacteria (LAB) Lactobacillus plantarum and Pediococcus pentosaceus were used as a mixed additive for the production of Orchardgrass silage by ensiled method and nutritional change fermentation ability and microbial content of experimental silages. The addition of LAB to Orchardgrass during ensiling process rapidly reduced the pH of the silages than the non-inoculated silages. In addition, the lactic and acetic acid content of silage was increased by LAB strains than the non-inoculated silages whereas butyric acid content was reduced in silage treated with LAB. A microbiological study revealed that higher LAB but lower yeast counts were observed in inoculated silages compared to non-inoculated silage. Overall data suggested that the addition of LAB stains could have ability to induce the fermentation process and improve the silage quality via increasing lactic acid and decreasing undesirable microbes.

• Journal of Powder Materials
• /
• v.30 no.4
• /
• pp.318-323
• /
• 2023

The thermoelectric effect, which converts waste heat into electricity, holds promise as a renewable energy technology. Recently, bismuth telluride (Bi2Te3)-based alloys are being recognized as important materials for practical applications in the temperature range from room temperature to 500 K. However, conventional sintering processes impose limitations on shape-changeable and tailorable Bi₂Te₃ materials. To overcome these issues, three-dimensional (3D) printing (additive manufacturing) is being adopted. Although some research results have been reported, relatively few studies on 3D printed thermoelectric materials are being carried out. In this study, we utilize extrusion 3D printing to manufacture n-type Bi_1.7Sb_0.3Te₃ (N-BST). The ink is produced without using organic binders, which could negatively influence its thermoelectric properties. Furthermore, we introduce graphene oxide (GO) at the crystal interface to enhance the electrical properties. The formed N-BST composites exhibit significantly improved electrical conductivity and a higher Seebeck coefficient as the GO content increases. Therefore, we propose that the combination of the extrusion 3D printing process (Direct Ink Writing, DIW) and the incorporation of GO into N-BST offers a convenient and effective approach for achieving higher thermoelectric efficiency.

• Journal of Microbiology and Biotechnology
• /
• v.33 no.4
• /
• pp.471-484
• /
• 2023

Compost is widely used as an organic additive to improve the bioremediation of diesel-contaminated soil. In this study, the effects of compost amendment on the remediation performance, functional genes, and bacterial community are evaluated during the bioremediation of diesel-contaminated soils with various ratios of compost (0-20%, w/w). The study reveals that the diesel removal efficiency, soil enzyme (dehydrogenase and urease) activity, soil CH₄ oxidation potential, and soil N₂O reduction potential have a positive correlation with the compost amendment (p < 0.05). The ratios of denitrifying genes (nosZI, cnorB and qnorB) to 16S rRNA genes each show a positive correlation with compost amendment, whereas the ratio of the CH₄-oxidizing gene (pmoA) to the 16S rRNA genes shows a negative correlation. Interestingly, the genera Acidibacter, Blastochloris, Erythrobacter, Hyphomicrobium, Marinobacter, Parvibaculum, Pseudoxanthomonas, and Terrimonas are strongly associated with diesel degradation, and have a strong positive correlation with soil CH₄ oxidation potential. Meanwhile, the genera Atopostipes, Bacillus, Halomonas, Oblitimonas, Pusillimonas, Truepera, and Wenahouziangella are found to be strongly associated with soil N₂O reduction potential. These results provide useful data for developing technologies that improve diesel removal efficiency while minimizing greenhouse gas emissions in the bioremediation process of diesel-contaminated soil.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.30 no.1
• /
• pp.25-34
• /
• 2010

Although whole crop barley (Hordeum vulgare L.) is now widely grown as a silage crop in Korea, forage production and silage quality of that for organic farm have not been published. Therefore, this experiment was conducted to evaluate the effect of harvest stage on forage production and quality of organic barley, and effect of field wilting and crushed rice for shortening of harvest date and improvement of forage quality. The experiment was split-plot design with three replications. Main plots were heading, milking and yellow stages, and sub-plot were field wilting for I day, crushed rice 10% (CR10%) and 15% (CR15%) treatments. The dry matter (DM) contents of heading, milking and yellow stages were 12.8%, 21.9% and 29.8%, respectively. The DM yields of heading, milking and yellow stages were 10,346, 15,819 and 18,336 kg/ha, respectively, and the total digestible nutrients (TDN) of these were 6,288, 9,550 and 10,178 kg/ha, respectively. The pH of milking stage showed low 4.00 pH values. The crude protein, ether extract, crude ash, non-fiber carbohydrate (NFC) and TDN contents were decreased as harvest stage progressed, while neutral detergent fiber (NDF) and acid detergent fiber (ADF) were increased. The crude ash (CA) of milking stage showed the lowest among harvest stages. Field wilting and crushed rice treatments decreased CA, NDF and ADF contents, and increased NFC and TDN contents. In vitro dry matter digestibility (IVDMD) decreased with progressed harvest stage, while field wilting and crushed rice treatments increased that of barley silage. Lactic acid and total organic acid contents of milking stage were the highest, and butyric acid of milking stage was the lowest among harvest stage. The good effect of field wilting and crushed rice was observed in heading stage. The experiment results indicate that optimum harvest stage of barley silage for organic was milking stage. The field wilting and crushed rice additive could be recommended as effective method for shortening harvest date and increasing forage quality of organic barley silage

• Asian-Australasian Journal of Animal Sciences
• /
• v.16 no.11
• /
• pp.1583-1591
• /
• 2003

The influence of varying levels of urea and additives on nitrogen (N) retention and chemical composition of wheat straw was studied. The wheat straw was treated with 4, 6 and 8% urea and ensiled with 1.5, 2 and 2.5% of acetic or formic acid and 2, 4 and 6% of corn steep liquor (CSL) or acidified molasses for 15 days. The N content of wheat straw was significantly different across all treatments. The N content of urea treated wheat straw was increased with the increasing level of urea. The N content was higher in urea treated wheat straw ensiled with acetic or formic acid as compared to urea treated wheat straw ensiled without these organic acids. The N content of urea treated wheat straw was further enhanced when it was ensiled with CSL or acidified molasses. This effect was significant across all levels of urea used to treat the wheat straw. Nitrogen retention in urea treated wheat straw was decreased linearly as the urea level was increased to treat the wheat straw. The N content was increased linearly when higher levels of CSL or acidified molasses were used to ensile the urea treated wheat straw. Most of the N in urea treated wheat straw was held as neutral detergent insoluble N (NDIN). The NDIN content was increased linearly with the increasing levels of urea and additives. The neutral detergent fiber (NDF) contents were higher in urea treated wheat straw ensiled with acetic or formic acid as compared to urea treated wheat straw ensiled without additive. The NDF content further increased in urea treated wheat straw ensiled with CSL and acidified molasses. The entire increase in NDF content was because of fiber bound N. The hemicellulose content of urea treated wheat straw ensiled with CSL or acidified molasses was higher as compared to urea treated wheat straw ensiled with acetic or formic acid. The acid detergent fiber content of urea treated wheat straw ensiled with or without additives remained statistically non-significant. The cellulose contents of wheat straw was linearly reduced when urea level was increased from 4 to 6 and 8% to treat the wheat straw. This effect was further enhanced when urea treated wheat straw was ensiled with different additives. The results of the present study indicated that fermentable carbohydrates might improve the Nitrogen retention and bring the favorable changes in physiochemical nature of wheat straw. However, biological evaluation of urea treated wheat straw ensiled with fermentable carbohydrates is required.

• Korean Journal of Food Science and Technology
• /
• v.22 no.6
• /
• pp.700-706
• /
• 1990

The curd yogurt was prepared from milk or milk added with skim milk powder or soy proteins. Acid production by lactic acid bacteria in milk containing additive of 2% was investigated and quality of curd yogurt(sensory property and keeping quality) was examined. Some organic acids in curd yogurt were analyzed by HPLC. The soy proteins, particularly defatted soy flour or soy flour, stimulated acid production by lactic acid bacteria more than skim milk powder. Among the four organisms tested, Leuconostoc mesenteroides and Lactobacillus bulgaricus produced more acid than L. casei and L. delbrueckii. HPLC analysis of organic acids in curd yogurt showed that the amount of lactic acid and acetic acid markedly increased during the fermentation by L. bulgaricus for 24 hours while the amount of citric acid markedly decreased. The major organic acid produced during the fermentation was lactic acid. Addition of soy proteins to milk reduced sensory property of curd yogurt. Among the soy proteins tested, soy protein concentrate or soy protein isolate added sample showed better sensory acceptability than other samples. When curd yogurt was kept at $5^{\circ}C$ for two weeks, titratable acidity, pH and number of viable cells of curd yogurt were not changed.

• Korean Journal of Agricultural Science
• /
• v.43 no.3
• /
• pp.387-393
• /
• 2016

This study was conducted to determine the fermentative characteristics of wheat bran inoculated with a starter culture of direct-fed microbes as a microbial wheat bran (DMWB) feed additive. Wheat bran was prepared with 1% (w/w, 0.5% Lactobacillus plantarum and 0.5% of Saccharomyces cerevisiae) starter culture treatment (TW) or without starter culture as a control (CW). Those were fermented under anaerobic conditions at $30^{\circ}C$ incubation for 3 days. Samples were taken at 0, 1, 2, and 3 days to analyze chemical composition, microbial growth, pH, and organic acid content. Chemical composition was not significantly different between CW and TW (p > 0.05). In TW, the number of lactic acid bacteria and yeast increased during the 3 days of fermentation (p < 0.05) and the population of lactic acid bacteria was significantly higher than in CW (p < 0.05). After 3 days, the number of yeast in TW was $7.50{\pm}0.07log\;CFU/g$, however, no yeast was detected in CW (p < 0.05). The pH values of both wheat bran samples decreased during the 3 days of fermentation (p < 0.05), and TW showed significantly lower pH than CW after 3 days of fermentation (p < 0.05). Contents of lactic acid and acetic acid increased significantly at 3rd day of fermentation in TW. However, no organic acids were generated in CW during testing period. These results suggest that 3 days of fermentation at $37^{\circ}C$ incubation after the inoculation wheat bran with starter culture makes it possible to produce a direct-feed with a high population of lactic acid bacteria at more than $10^{11}CFU/g$.