• Journal of environmental and Sanitary engineering
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• v.14 no.2
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• pp.90-95
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• 1999

The study on the fermented feeds production of garbages have been conducted to determine the optimum operation condition. The process variables considered for this study were initial air flow rate and temperature control. The results showed that optimum air requirement was $4{\ell}-air/min{\cdot}kg-$ garbages on dry weight basis which is equal to $0.8{\ell}-air/min{\cdot}kg-$ garbages on the basis of 80% moisture content. The optimum initial temperature control in the reactor was $40^{\circ}C$. Crude fiber content of fermented final byproducts were higher than feedstuffs standard for pig breeding and consequently final byproducts had to mix with single-component feed.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.761-764
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• 2005

Epoxy resin, as no-hardening, applied for repair and finish materials is used to mix together with hardener. It is advantages that epoxy resin has reaction shrinkage less than other materials and has excellent in water proofing, thermal resistance. The other hands, because ratio of combination of epoxy resin and hardener is fixed, it is not possible to change according to field condition. This investigated suspended time by temperature and hardener ratio. As a results of study, it can select economical ratio of the epoxy resin and hardener according to site situation.

• Journal of the Korean Ceramic Society
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• v.31 no.11
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• pp.1387-1395
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• 1994

Re-hydration properties of heated and ground CaO-SiO2-H2O system were studied under hydrothermal condition in order to examine the possibility of recycling ALC waste as raw materials of ALC. Powder of calcium silicate hydrates and ALC waste without heat treatment did not show further hydration while those of heat-treated at proper temperature showed re-hydration properties under hydrothermal condition. The lath-like shape of initially synthesized tobermorite was gradually turned into small debris during heating and plate-like tobermorite was crystallized during re-hydration of the heated powders. Heated and ground ALC waste could be added to natural raw mix for ALC at the ammount up to 20% with increased compressive strength and up to 30% with slightly decreased compressive strength. The optimum heating temperature of ALC for recycling was about 50$0^{\circ}C$.

• International Journal of Concrete Structures and Materials
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• v.7 no.2
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• pp.165-174
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• 2013

Portland cement concrete exposed to high temperatures during mixing, transporting, casting, finishing, and curing can develop undesirable characteristics. Applicable requirements for such the hot weather concrete differ from country to country and government agencies. The current study is an attempt at evaluating the hardened properties of the concrete exposed to hot weather in fresh state. First of all, this study reviews the current state of understanding and practice for hot weather concrete placement in US and then roadway sites with suspected hot weather concrete problems were investigated. Core samples were obtained from the field locations and were analyzed by standard resonance frequency analysis and the boil test. Based on the results, there does not appear to be systematic evidence of frequent cracking problems related to high temperature placement. Thus, the suspicious deteriorations which are referable to hot weather concreting would be due to other factors.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.107-111
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• 1996

The testing specimens were made from the standard mix proportion according to those of domestic PC factories to establish a basic data for the Accelerated Curing Effect. The experimental tests were conducted according to the conditions of each sub-curing periods. By comparing the results of compression tests on de-molded and 28-day water-curing specimens, we find that the most effective curing condition to obtain more than the required design strength after 28 days of water curing may be as follwings; the presteaming period does not affect seriously and less than $30^{\circ}C$/hr-the rate of temperature rise and less than $82^{\circ}C$ - maximum temperature are necessary. It seems that post-curing procedure is very important factor to increase the effect of accelerated curing.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.334-334
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• 2011

We applied N-ion bombardment and heat treatment to the Cu thin films deposited on aluminum oxide layer for the enhancement of adhesion. With e-beam evaporation method. $1,000{\AA}$ thick Cu pre-bombardment layer was deposited on the aluminum oxide surface and then N-ion beam was bombared in order to mix the atoms at the film/substrate interface. Additional $4,000{\AA}$-thick Cu film was the coated. Subsequently, the ion mixide Cu on aluminum oxide was annealed at $200^{\circ}C$ and $300^{\circ}C$ in vacuum.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.3
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• pp.123-128
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• 2013

This study was performed to evaluate the slump flow, air content, setting time, compressive strength, adiabatic temperature rise and diffusion coefficient of chloride used ordinary portland cement, crushed coarse aggregate, crushed sand, river sand, fly ash, limestone powder, blast furnace slag powder and superplasticizer to find optimum mix design of low carbon green concrete for structures. The performances of low carbon green concrete used fly ash, limestone powder and blast furnace slag powder were remarkably improved. This fact is expected to have economical effects in the manufacture of low carbon green concrete for structures. Accordingly, the fly ash, limestone powder and blast furnace slag powder can be used for low carbon green concrete material.

• Environmental Engineering Research
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• v.17 no.2
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• pp.69-75
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• 2012

Composting of water hyacinth, mixed with cattle manure, rice husk and sawdust in four different proportions, was performed in a pilot scale rotary drum composter. The physico-chemical characteristics, i.e., temperature, moisture content, pH, electrical conductivity, total organic matter (OM), nitrogen dynamics and nutrients were evaluated during the 20 days composting process. The stabilities of the composts were also investigated with respirometric analysis, i.e., $CO_2$ evolution rates and oxygen uptake rate (OUR). Among all trials, trial 1 (6 water hyacinth, 3 cattle manure, 1 rice husk) indicated the best composting mix, as shown by the highest temperature profile and OM loss, and lowest $CO_2$ evolution rate and OUR.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.69-72
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• 2005

In this study, it is contents to application on AE water reducing admixture for high early strength, which reduce to construction period for cost down in construction. In experiment result on the kinds of AE water reducing admixture for concrete strength promotion, when passed 60 minutes, while it was happened on lignin and naphthalene system about $30\∼35\%$ that loss related to slump, slump flow and air, but happened about $8\∼10\%$ on polycarboxylic system. And the result of compressive strength tests, when 32 hours passed in polycarboxylic system than lignin and naphthalene system, was showing an increase of 10$\%$. Accordingly, concrete properties was measured to condition change by the addition amount and curing temperature of polycarboxylic system. The required curing temperature to gain 5MPa of compressive strength, which is capable of side form stripping, must keep more than smallest 12. 5$^{circ}C$ when polycarboxylic system is used. As a result, AE water reducing admixture of polycarboxylic system may apply effectively to high early strength concrete

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.159-159
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• 2000

Initial growth mode of Nb on Cu(100) is studied by scanning tunneling microscopy (STM) and density functional theory. Nb/Cu is immiscible at room temperature, but isolated Nb atoms are expected to be incorporated up to the second layer by DFT. STM shows that Nb atoms mix with Cu atoms in the first layer at room temperature and diffuse into the second layer upon annealing. In the second layer, Nb/induced features are preferentially found at step edges and appear as bright dots surrounded by dark rings. Details of comparison between experiment and theory will be discussed.