• Journal of The Korean Society of Agricultural Engineers
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• v.64 no.5
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• pp.9-16
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• 2022

Syngas, also known as synthesis gas, synthetic gas, or producer gas, is a combustible gas mixture generated when organic material (biomass) is heated in a gasifier with a limited airflow at a high temperature and elevated pressure. The present research was aimed at modifying the existing LPG engine generator for fully operated syngas. During this study, the designed gasifier-powered woodchip biomass was used for syngas production to generate power. A 6.0 kW LPG engine generator was modified and tested for operation on syngas. In the experiments, syngas and LPG fuels were tested as test fuels. For syngas production, 3 kg of dry woodchips were fed and burnt into the designed downdraft gasifier. The gasifier was connected to a blower coupled with a slider to help the air supply and control the ignition. The convection cooling system was connected to the syngas flow pipe for cooling the hot produce gas and filtering the impurities. For engine modification, a customized T-shaped flexible air/fuel mixture control device was designed for adjusting the correct stoichiometric air-fuel ratio ranging between 1:1.1 and 1.3 to match the combustion needs of the engine. The composition of produced syngas was analyzed using a gas analyzer and its composition was; 13~15 %, 10.2~13 %, 4.1~4.5 %, and 11.9~14.6 % for CO, H₂, CH₄, and CO₂ respectively with a heating value range of 4.12~5.01 MJ/Nm³. The maximum peak power output generated from syngas and LPG was recorded using a clamp-on power meter and found to be 3,689 watts and 5,001 watts, respectively. The results found from the experiment show that the LPG engine generator operated on syngas can be adopted with a de-ration rate of 73.78 % compared to its regular operating fuel.

• Journal of Bio-Environment Control
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• v.33 no.1
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• pp.45-54
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• 2024

A proper level of UV-A light treatment in terms of intensity, spectrum, and exposure duration is known to have a positive impact on plant growth, photosynthesis, and the biosynthesis of secondary metabolites. However, there are few studies investigating the physiological responses of spinach (Spinacia oleracea L.) to UV radiation. Hence, this study aimed to assess the effects of short-term UV-A radiation on the growth and bioactive compounds of spinach. Spinach seedlings were cultivated in a vertical farm module under the following environmental conditions: photosynthetic photon flux density 200 µmol·m^-2·s^-1, white LED, 12 h on/off, 20℃ air temperature, 70% relative humidity, and 500 µmol·mol^-1 CO₂ concentration. After 5 weeks of sowing, the seedlings were subjected to continuous UV-A (peak wavelength; 385 nm) irradiation at two different energy levels: 20 W·m^-2 and 40 W·m^-2 for 7 days. As a result, the UV-A_20W treatment increased the shoot fresh and dry weights of spinach. However, there were no significant differences observed in photosynthetic parameters between the UV-A treatments and the control. The maximum quantum efficiency of photosystem II (Fv/Fm) consistently decreased across all UV-A treatments for 7 days in UV-A treatments. Additionally, the total phenolic content and antioxidant capacity increased in the UV-A_20W treatment at 7 days of treatment as well as the total flavonoid content significantly increased at 5 and 7 days of treatment. These findings suggest that supplemental UV-A LED radiation can enhance the growth and quality of spinach cultivated in closed type plant production systems such as vertical farms.

• Applied Chemistry for Engineering
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• v.19 no.5
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• pp.519-525
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• 2008

Biodegradation of toluene, styrene and hydrogen sulfide as model compounds of volatile organic compounds and odor from waste gas was investigated experimentally in a biotrickling filter. This study focussed on the description of experimental results with regard to operating conditions. The effect of varying $H_2S$ load rate and inlet concentration was investigated under autotropic and mixotropic environmental conditions. The $H_2S$ removal efficiencies of greater than 99% were achieved at $H_2S$ loads below $10g/m^3{\cdot}hr$ for each environment. It was observed that the maximum elimination capacity of mixotrophic filter was achieved a little greater than the one of autotrophic filter. The biofiltration of toluene and styrene in trickling bed was examined under different gas flow rates, load rates, and inlet concentrations. Below $40g/m^3{\cdot}hr$ of toluene loading, the elimination capacity and loading were identical and it was completely destroyed. In high loading of toluene, the biotrickling filter was operated at its maximum elimination capacity. In the inlet concentration of 0.2, 0.5, and $1.0g/m^3$, the maximum elimination capacity of toluene showed 40, 45, and $60g/m^3{\cdot}hr$, respectively. After a short adaptation period, it was demonstrated that the results of styrene in originally toluene adapted bioreactor was similar with the ones of toluene. However, the performance of filer for styrene is generally a little lower than for toluene. The operating conditions (including liquid flow rate etc.) allowing the highest removal efficiency should be determined experimentally for each specific case.

• Clinical and Experimental Reproductive Medicine
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• v.43 no.4
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• pp.193-198
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• 2016

Objective: Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human enzyme defect. G6PD plays a key role in the pentose phosphate pathway, which is a major source of nicotinamide adenine dinucleotide phosphate (NADPH). NADPH provides the reducing equivalents for oxidation-reduction reductions involved in protecting against the toxicity of reactive oxygen species such as $H_2O_2$. We hypothesized that G6PD deficiency may reduce the amount of NADPH in sperms, thereby inhibiting the detoxification of $H_2O_2$, which could potentially affect their motility and viability, resulting in an increased susceptibility to infertility. Methods: Semen samples were obtained from four males with G6PD deficiency and eight healthy males as a control. In both groups, motile sperms were isolated from the seminal fluid and incubated with 0, 10, 20, 40, 60, 80, and $120{\mu}M$ concentrations of $H_2O_2$. After 1 hour incubation at $37^{\circ}C$, sperms were evaluated for motility and viability. Results: Incubation of sperms with 10 and $20{\mu}M\;H_2O_2$ led to very little decrease in motility and viability, but motility decreased notably in both groups in 40, 60, and $80{\mu}M\;H_2O_2$, and viability decreased in both groups in 40, 60, 80, and $120{\mu}M\;H_2O_2$. However, no statistically significant differences were found between the G6PD-deficient group and controls. Conclusion: G6PD deficiency does not increase the susceptibility of sperm to oxidative stress induced by $H_2O_2$, and the reducing equivalents necessary for protection against $H_2O_2$ are most likely produced by other pathways. Therefore, G6PD deficiency cannot be considered as major risk factor for male infertility.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.100-103
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• 2005

In this study, tool path control algorithm for aspherical surface grinding was derived and discussed. The aspherical surface actually means contact points between lens and tool. Tool positions are generally defined at the center of a tool, so there is difference between tool path and lens surface. The path was obtained from contact angle and relative position from the contact point. The angle could be calculated after differentiating an aspheric equation and complex algebraic operations. The assumption of the control algorithm was that x moves by constant velocity while z velocity varies. X was normal to the radial direction of lens, but z was tangential. The z velocities and accelerations were determined from current error and next position in each step. In the experiment, accuracy of the control algorithm was checked on a micro-precision machine. The result showed that the control error tended to be diminished when the tool diameter increased, and the error was under sub-micro level.

• Journal of Environmental Science International
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• v.24 no.10
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• pp.1309-1313
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• 2015

The effects of Houttuynia cordata powder on the growth performance of ducks were investigated. Ninety ducks were assigned into one of three dietary treatments as a completely randomized design for 6 weeks: feeds supplemented with 1% or 2% H. cordata and a control group. No significant difference was observed in feed conversion among the three groups (p > 0.05), but addition of H. cordata had a significantly positive effect (p < 0.05) on initial and final body weight, weight gain, and feed intake of the ducks. Furthermore, the effects of chemical treatment (comprising 50 g and 100 g aluminum chloride [$AlCl_3$] per kilogram litter) on the ammonia ($NH_3$) flux in duck litters were also investigated. Duck litter was treated with $AlCl_3$ at a depth of 8 cm by top-dressing; this resulted in a significant difference on $NH_3$ flux (p < 0.05) during the experimental period (but not at 2 weeks). $NH_3$ flux at 6 weeks were reduced by 25.4% and 37.5% by treatment with 1% and 2% H. cordata, respectively, compared with the control groups. In conclusion, enriching the diets of the ducks with 2% H. cordata and adding 100 g $AlCl_3$ to their litter has beneficial effects on increasing their growth performance and reducing $NH_3$ flux in their environment.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.1
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• pp.103-106
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• 2008

A broiler experiment was conducted to compare the effects of supplementary iron sources and levels on the iron content of broiler meat. Two hundred and fifty hatched Ross broiler chickens were randomly assigned to 5 dietary treatments. Each treatment had 5 replicates of 10 birds (5 males and 5 females). Birds were housed in raised floor batteries and fed traditional broiler diets ad libitum for 5 weeks. Dietary treatments were as follows: Control, Fe-Met 100 (100 ppm iron as Fe-methionine), Fe-Met 200, $FeSO_4$ 100 (100 ppm iron as $FeSO_4{\cdot}7H_2O$) and $FeSO_4\;200$. There were no significant differences among treatments in parameters related to production performance. Liver contained approximately 10 times more iron than the leg muscle which contained approximately 3 times more iron than either breast muscle or wing muscle. Significant differences in iron content in the broiler meat were observed. In the breast meat, Fe-Met treatments were significantly (p<0.05) higher than other treatments in iron content. In the leg meat, Fe-Met treatments and $FeSO_4\;200$ treatment were significantly higher than the control in iron content. In the wing muscle, Fe-Met 200 treatment was significantly higher than other treatments in iron content. Iron content in the liver was significantly influenced by source and supplementation level of iron. Fe-Met treatments were higher than $FeSO_4$ treatments and 200 ppm treatments were higher than 100 ppm treatments in iron content in the liver. It is concluded that iron-methionine chelate is more efficient than iron sulfate and 200 ppm iron supplementation as Fe-Met is recommended for maximum iron enrichment in broiler meat.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.4
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• pp.35-42
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• 2019

Organic fertilization (OF) was an effective management strategy to improve crop yield and soil fertility. Determination of optimum application rate has been received great interest as a major research field. In this study, we evaluated optimum application level of three different organic fertilizers; mixed expeller compost (MEC), mixed organic fertilizer (MOF) and organic complex fertilizer (OCF), for garlic cultivation. Treatments consisted of MEC, MOF, OCF (50, 100, 150% of standard nitrogen input), inorganic fertilizer(NPK, N-P₂O₅-K₂O : 250-78-128 kg ha^-1) and no-fertilization (control). Overall, the yields of garlic under MEC, MOF and OCF 100% (5,337, 5,617 and 5,276 kg ha^-1) were higher than under control (4,496 kg ha^-1). The 100% of three OFs treatements showed the highest yield and bulb diameter, similar with NPK, while leaf length and bulb height were not significantly different among all treatments. The 150% of three OFs rather decreased yield. The highest nitrogen use efficiency (38.4 and 38.0%) was observed in MOF 100% and OCF100%, which was the most similar with that in NPK (38.8%). As OF application rate increased, pH was decreased, but soil NO₃-N and NH₄-N were increased. There was no significant difference in soil organic matter (OM), av. P₂O₅ and Ex. cation values. From these results, 100% application of OFs could be recommended as a suitable input level for garlic cultivation, regardless of organic fertilizer types. Further study might be required to evaluate long-term OF application effect on soil health and crop productivity.

• Membrane Journal
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• v.33 no.6
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• pp.362-368
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• 2023

This research article explores the application of Polymer of Intrinsic Microporosity (PIM-1) as a cutting-edge material for CO₂ gas separation membranes in response to the escalating global concern over climate change and the imperative to reduce greenhouse gas emissions. The study delves into the synthesis, molecular weight control, and fabrication of PIM-1 membranes, providing comprehensive insights through various characterization techniques. The intrinsic microporosity of PIM-1, arising from its unique crosslinked and rigid structure, is harnessed for selective gas permeation, particularly of carbon dioxide. The article emphasizes the tunable chemical properties of PIM-1, allowing for customization and optimization of gas separation membranes. By controlling the molecular weight, higher molecular weight (H-PIM-1) membranes are demonstrated to exhibit superior CO₂ permeability and selectivity compared to lower molecular weight counterparts (L-PIM-1). The study's findings highlight the critical role of molecular weight in tailoring PIM-1 membrane properties, contributing to the advancement of next-generation membrane technologies for efficient and selective CO₂ capture-an essential step in addressing the pressing global challenge of climate change.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.10
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• pp.1500-1506
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• 2017

Objective: High $NH_3$ emissions from poultry houses are reported to have negative impacts on health, welfare and safety of birds and humans, and on the environment. Objective of the present study was to determine the effects of two litter amendments on the $NH_3$ levels in broiler closed houses under hot-humid conditions. Methods: Giving a completely randomize design, nine closed houses, each housed 32,500 birds on paddy husk litter, were randomly allocated into two treatment (Mizuho; a bacterial culture mix and Rydall OE; an enzymatic biocatalyst) and control groups. $NH_3$ levels were determined thrice a day (0600, 1200, and 1800 h), at three heights from the litter surface (30, 90, and 150 cm), at 20 predetermined locations of a house, from day 1 to 41. Results: Rydall significantly reduced the $NH_3$ level compared to control and Mizuho. $NH_3$ levels at 30 cm were significantly higher than that of 90 and 150 cm. The $NH_3$ levels at 30 cm height were higher than 25 ppm level from day 9, 11, and 13 in Mizuho, control, and Rydall groups, respectively to day 41. $NH_3$ levels at 150 cm height were higher than maximum threshold limit of 50 ppm for human exposure from day 12, 14, and 15 in Mizuho, control, and Rydall groups, respectively to day 33. Being significantly different among each other, the $NH_3$ level was highest and lowest at 0600 and 1800 h. Litter amendments had no significant effects on growth performance. Rydall significantly increased the litter N content on day 24. Conclusion: It was concluded that the $NH_3$ levels of closed house broiler production facilities under tropical condition are so high that both birds and workers are exposed to above recommended levels during many days of the growing period. Compared to microbial culture, the enzymatic biocatalyst was found to be more effective in reducing $NH_3$ level.