• Journal of Advanced Marine Engineering and Technology
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• v.23 no.2
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• pp.184-191
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• 1999

Th effects of exhaust gas recirculation(EGR) on the characteristics of combustion exhaust emissions and specific fuel consumption(SFC) are experimentally investigated by four-cylin-der four-cycle and direct injection marine diesel engine. In order to reduce soot contents in the recirculated exhaust gas to intake system of the engines a novel diesel soot removal system with a cylinder-type scrubber which has water injector(4 nozzles in 1.0mm diameter)is specially designed and manufactured for the experi-mental system. The obtained results are as follows; The combustion pressure in cylinder is decreased and ignition is delayed with increasing EGR rate. The accumulated quantity of heat release is slightly decreased and the tendency of heat release rate is not constant. NOx and Soot emissions are decreased by maximum 7% and 540% with scrubber tan without scrubber in the range of experimental conditions. Those are increased at the lean burn area with increasing equivalence ration in the constant value of engine speed and EGR rate. Also those are decreased with increasing EGR rate in the constant value of engine speed and equivalence ratio.

• Korean Journal of Poultry Science
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• v.17 no.4
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• pp.281-283
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• 1990

Ten-week-old layer type pullets were used in this study, housed 10 birds per cage(61$\times$41cm) and were replicated 15 times After raising them on a 19% protein diet up to ten weeks of age they were fed a 12% protein corn-soy control diet or one with half or all of the soybean mea replaced with ground full-fat sunflower seeds. At 19 weeks of age, pulltes were transferred to a layer house and their respective diet was gradually changed to a 13.5% layer diet containing 635% oats. The 19% protein SFS diet in treatment 2 did not show my, adverse effect on body weight or subsequent egg productio. The higher level of SES(38%) appeared to delay sexual maturity somewhat as was indicated by body weight and egg production data. However, the higher replacement of soybean with SFS(38%) in the pullet ration may not be critical for sexual maturity, but beneficial in a full laying cycle. There were no adverse effects on later stages of production.

• Journal of Aquaculture
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• v.4 no.1
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• pp.31-66
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• 1991

This paper deals with the reproductive ecology e.g., number of the pre-spawning moults, morphological characteristics of the pre-spawning moult the common moult, daily ration druing a molting cycle mating behavior, structures of spermatozoa and spermatophore, structure of vas deferens, mechanisms of the oviposition and brooding into the egg-chambers, a suitable time for the artificial mating and fertilization, time sequence of the oviposition and brooding into egg-chambers from the copulation, responses to temperature and chlorinity on the egg development and hatching, effect of temperatures on duration of egg development, physical mechanism of the egg hatching, to make an attempt for the artificial spawning and brooding to establish a suitable system of the artificial seedling-production for the aquaculture. 1. Females molted commonly $8{\~}10$ times at an interval of $17{\~}18$ days at $28^{\circ}C,\;3.26\~4.35\%_{\circ}$ while the prespawning moltings were $4{\~}5$ times at an interval of $13{\~}14$ days. The suitable state for artificial copulation was within 14 hours elapsed from the prespawning moltings (most suitable state was within 8 hours). Males discharged a gelatinous spermatophore and placed it on the females sternum during copulation. Oviposition was seen $6{\~}17$ hours after copulation. External fertilization was considered to take place at oviposition. Fertilized eggs held in egg-chambers forming between pleopods were about $5000{\~}6000$ in females those sizes about 6.5 cm in body length. 2. Eggs immediately after oviposition were elliptic shape, measuring $0.58{\times}0.48$ mm up to hatching. Their sizes increased with egg development and finally reached $0.85{\times}0.54$ mm up to hatching. The relationship between the long axis of the egg(Y in U) and days elapsed(X) was expressed as Y= 5.60194 + 0.007358X. The eggs performed superficial cleavage and their cleavage furrows became visible at the 4-daughter-nucleus stage. The eggs showed normal development up to hatching at water temperature range of $22{\~}30^{\circ}C$ (optimum temperature : $26{\~}28^{\circ}C$) and at chlorinity range of $0.00\~6.64\%_{\circ}$ (optimun chlorinity : $2.21{\%}_{\circ}$). The relationship between incubation period (Y in days) and water temperature(X in $^{\circ}C$) could be expressed as Y= 50.803-1.3555X. The eggs hatched $12{\~}13$ days after oviposition at $28.0{\~}28.6^{\circ}C$ 3. The pre-spawning moltings were appreciably different in the morphologic structure from those of common moltings. Breeding setae and dresses were formed on the thoracic regions, abdominal epimerae and the bases of the first to fourth pleopods in order to prepare and support oviposition, transfering and supporting eggs in egg-chambers up to hatching. These supplementary breeding organs were observed only at reproductive seasons.

• Resources Recycling
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• v.32 no.3
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• pp.57-67
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• 2023

The treatment of waste plastic has primarily been entrusted to small companies, which has resulted in challenges in obtaining an accurate overview of the current state of affairs and ensuring profitability. Consequently, despite the presence of recycling technology, their practical application has proven to be challenging. In this study, as part of the waste plastic material recycling plan, it is assumed that the PET/OPP laminated waste film is peeled off at the waste film generation site for the second use. The recycling rate of PET/OPP delaminated waste film is assumed to be 2%, 10%, and 30% referring to the figures suggested by "Life-cycle Post Plastic Measures" from the Korean government. In this study, a physical separation method was developed as a recycling approach for waste PET. A result of cost-benefit analysis was conducted to evaluate the economic viability of the recycling process based on changes in the recycling rate. The findings indicated that a recycling rate of waste PET was 30% or higher resulted in a cost-benefit ratio (Benefit-cost ratio, BCR) of 1.32, exceeding the threshold of BCR ≥1, which is considered to meet the minimum requirement for cost-benefit balance. As the government's allocation ratio and unit price are expected to increase in the future, the cost-benefit ratio is expected to increase further. This case is expected to serve as a pilot initiative for waste PET recycling and foster profit creation for businesses in similar industries.