• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.489-494
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• 2010

A geo-composite soil (GCS) is a stabilized mixture of bottom ash, cement and dredged soil. Various samples with different mass ratios of mixtures were tested under curing time of 7 and 28 days to investigate physical properties and compressive strength. This paper focused on the effect of bottom ash on the strength characteristics of Busan marine dredged soil. Cement has been added as an additive constituent to enhance self-hardening of the blended mixture. The unconfined compressive strength of GCS increases with an increase in curing time due to pozzolanic reaction of the bottom ash. The strength after 28 days of curing is found to be approximately 1.3 to 2.0 times the strength after 7 days of curing, regardless of mixture conditions. The secant modulus of GCS is in the range of 55 to 134 times the unconfined compressive strength. The correlation of unconfined compressive strength with bottom ash content and initial void ratio are suggested.

• 한국세라믹학회지
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• 제27권7호
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• pp.833-840
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• 1990

For the development of multi-functional materials which has water reducing power, air entraining power and waterproofing power as well as blending additive in cement mortar the coal ash was modified with asphalt-stearic acid or asphalt-boiled oil mixtures by mechanical treatment. And the physical properties of cement mortar blended with modified coal ashes were compared with those of the water-tightness-cement mortar and the ordinary-portland-cement mortar added with AE.water reducing agent. The mortar of coalash-blend-cement modified with asphalt-stearic mixture was increased acid about 20% in initial strengths and decreased about 20% in water absorption ratio than those of ordinary coalash-blend-cement. The mortar of coalash-blend-cement modified with asphalt-bolied oil mixture was similar to the cement mortar added with AE.water reducing agent in water reduction ratio, air entraining conents and the initial strengths, also was similar to the water-tightness-cement mortar in water absorption and water permeability ratios.

• Advances in aircraft and spacecraft science
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• 제5권5호
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• pp.533-550
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• 2018

Detonation transmission between propane/oxygen (donor) and propane/air (acceptor) with an abrupt area change is experimentally studied. In the donor, there are two types of incident detonation waves: A self-sustained Chapman-Jouguet (CJ) detonation wave and an overdriven detonation wave that is a result of the difference in the initial donor pressure ratios. The piston work is used to characterize the strength of the incident detonation wave. For an incident CJ detonation wave, the re-initiation of a detonation wave in the acceptor depends on the initial pressure in the donor and the expansion ratio. The axisymmetric and non-axisymmetric soot patterns respectively correspond to direct detonation and detonation re-initiation. For an incident overdriven detonation wave, the re-initiation of a detonation wave in the acceptor strongly depends on the degree of overdrive.

• International Journal of Automotive Technology
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• 제2권1호
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• pp.25-31
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• 2001

It is necessary to understand the combustion process and cycle-by-cycle variation in combustion to improve the engine stability and consequently to improve the fuel economy and exhaust emissions. The pressure related parameters instead of mass fraction burned were compared for the effect of initial combustion pressures on the following combustion and the analysis of cycle-by-cycle variation in combustion for two pen injected SI engines. The correlation between IMEP and pressures at referenced crank angles showed almost the same trends for equivalence ratios, but the different mixture preparations indicated different tendency. The dependency of IMEP on pressure at the referenced crank angles increases as the mixture becomes leaner for both engines. The mixture distribution in the combustion chamber was varied with the coolant temperature and intake valve deactivation due to the evaporation of fuel and air motion. The correlation between pressure related parameters were also compared for the coolant temperatures and air motion.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1997년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Fall 1997
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• pp.265-272
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• 1997

This paper presents the result of an international cooperative research on the post-correlation analysis of forced vibration tests and the prediction of earthquake responses of a large-scale seismic test structure. Through the post-correlation analysis, the properties of the soil layers are revised so that the best correlation in the responses may be obtained compared with the measured force vibration test data. Utilizing the revised soil properties as the initial linear values, the seismic responses are predicted for an earthquake using the equivalent linearlization technique based on the specified strain dependent characteristics of the shear moduli and damping ratios. It has been found that the predicted responses by the equivalent nonlinear procedure are in excellent agreement with the observed responses, which those using the initial properties are fairly off from the measured results.

• 대한기계학회논문집
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• 제18권12호
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• pp.3335-3344
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• 1994

The initial flow characteristics of the turbulent circular jet discharging into the sudden expansion pipes have been investigated by the hot wire anemometry. Evolutions of similarity, centerline behavior, jet boundary and typical turbulent quantities were looked into for the expansion ratios. The results show that the spreading rates of discharging jet seem not to be dependent of the expansion ratio and that the velocity profiles in the radial directions exhibit the similarity in the regions, 2-5d, 2-6d and 3-8d for the corresponding expansion rations of 2, 3 and 5, respectively. With the increase of expansion ratio the centerline velocity decays rather slowly. The anisotropic behaviors of the discharging jets into the sudden expansion pipe look stronger than those of the free jet.

• 한국자동차공학회논문집
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• 제11권5호
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• pp.83-88
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• 2003

Measurements on the combustion characteristics of dimethyl ether(DME:$CH_3$O$CH_3$) as compared with LPC in constant volume combustion chamber have been conducted. The DME is a good alternative fuel having oxygen component in fuel. To elucidate the combustion characteristics of dimethyl ether as a fuel, the combustion pressures, combustion durations, and pollutants(NOx, $CO_2$, CO) are measured with equivalence ratios(Ø), and initial Pressures of fuel-air mixture. In the case of DME, the NOx concentration peaks in leu flame Ø = 0.85~0.9, and $CO_2$ concentration peaks at Ø=1.1, while the CO concentration abruptly rises at the condition of fuel-rich mixtures.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 추계학술대회 논문집
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• pp.326-327
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• 2007

A study on the texture and the formability after asymmetric rolled and subsequent heat-treated AA 1050 aluminum alloy sheets have been carried out. The specimens after the asymmetric rolling showed a very fine grain size, a decrease of <100>//ND, and an increase of <111>//ND textures. The change of plastic strain ratios has been investigated and it was found that they were higher than those of the initial Al sheet.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 추계학술대회 논문집
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• pp.328-329
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• 2007

A study on the texture and the formability after frictional rolled and subsequent heat-treated AA 1050 aluminum alloy sheets have been carried out. The specimens after the frictional rolling showed a very fine grain size, a decrease of <100>//ND, and an increase of <111>//ND textures. The change of plastic strain ratios has been investigated and it was found that they were higher than those of the initial Al sheet.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1992년도 봄 학술발표회 논문집
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• pp.53-58
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• 1992

This research is related to the experimental investigation of the inelastic behavior of R/C columns with high strength concrete. A total of eight specimens have been tested with different span ratios, steel reinforcements and load applications. Through tests bending moments were applied incrementally while axial forces being kept constantly at 80 tons. Careful observation were given to initial crack formation, crack patterns and propagation paths. Comparative studies have been made on the load carrying capacity for R/C columns with high strength concrete versus normal strength concrete.