• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2004.05a
• /
• pp.33-37
• /
• 2004

Recently, Growing tendency for structure surface to use water repellent agent has increased steadily. But investigation of it's protection and durability property is not sufficient. Therefore, this paper shows the investigation about repellent property and micro structure's change in surface layer of mortar that is applied by water repellent agent. Water repellent property, absorption coefficient, air permeability, porosity and observation of micro construct was investigated according to water repellent agent type. The test results indicated that mortar applied water repellent agent appears tiny absorption coefficient, but air permeability is maintained. The reason is because silane solution is coating at capillary surface of a wall and minute pore structure is changeless.

• Journal of the Korean Ceramic Society
• /
• v.27 no.7
• /
• pp.833-840
• /
• 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.

• Solar Energy
• /
• v.18 no.3
• /
• pp.107-112
• /
• 1998

Basic design of a solar driven absorption cooling machine(SDACM) with a cooling capacity of 5 USRT was carried out. The SDACM is a single effect cycle driven by low temperature hot water from solar collectors. The SDACM design data were calculated by the steady state simulation program which was developed in this study The variation of COP and cooling capacity of the SDACM were investigated at different off-design conditions. Both the cooling capacity and the system COP were improved with decreasing cooling water temperature. If hot water temperature was increased, the cooling capacity was improved but the system COP was found to be decreased. The decrease of the system COP were basically caused by increased thermal loads in the system components.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.2
• /
• pp.597-600
• /
• 2012

Polyynes were formed by laser ablation of a graphite target in deionized water ($H_2O$ and $D_2O$) and various organic solvents such as acetonitrile, n-hexane, and c-hexane and were identified by analyzing ultraviolet (UV) absorption and Raman spectra. We assigned the major UV absorption peaks that coincided with the electronic transitions corresponding to linear polyyne chains. The UV absorption peak intensities of a polyyne solution decreased as the holding temperature of the solution increased. Also, the absorption spectra of polyynes obtained by laser ablation of a graphite target at different volume fractions of $H_2O$ and $D_2O$ were examined.

• Structural Engineering and Mechanics
• /
• v.51 no.3
• /
• pp.403-412
• /
• 2014

In this paper, enhancement of corrosion and chloride resistance of high performance self compacting concrete (SCC) through incorporating nanosilica into the binder has been investigated. For this purpose, different mixtures were designed with different amounts of silica fume and nano silica admixtures. Different binder contents were also investigated to observe the binder content effect on the concrete properties. Corrosion behavior was evaluated by chloride penetration and resitivity tests. Water absorption and capillary absorption were also measured as other durability-related properties. The results showed that water absorption, capillary absorption and Cl ion percentage decreased rather significantly in the mixtures containing admixtures especially blend of silica fume and nano silica. By addition of the admixtures, resistivity of the SCC mixtures increased which can lead to reduction of corrosion probability.

• Korean journal of food and cookery science
• /
• v.7 no.4
• /
• pp.71-86
• /
• 1991

This study was attempted to enhance nutritional value of cooked rice by adding milk in cooking water. Cooked and soaked rice with five different levels of milk in cooking water (0%, A: 30%, B: 50%, C: 70%, D: 100%, E) was tested for rheological parameters, fine structural changes, sensory evaluation. 1. Water absorbance of raw rice in cooking water with varying amountes of milk, was tested at $5^{\circ}C$ and $15^{\circ}C$ for 2 hours. Water absorption ratio was decreased as milk content was increased and soaking temperature was low. Time for maximum water absorption of sample A was 40 min at 1$15^{\circ}C$ but for sample B to D, it was not reached until 120 min. 2. Electronmicroscopic observation revealed that starch granules of rice lost their regular forms by soaking for 90 minutes, but recovered most of initial regularity after 24 hours. Increase in milk content of soaking water decreased marginal sharpness of the starch granule, presumably due to reduced swelling of the granule. 3. Degree of gelatinization of cooked rice was highest in sample A and progressively decreased as milk content was increased. It was, however, increased in all samples when the cooking water to rice ratio was raised from 160% to 180%. During 4 hour storage, rates of retrogradation were not different between A and B samples, but those of C, D and E were about 2.5 times higher than A and B under the optimal condition of 170% cooking water to rice ratio. This was in the order reverse to hardness order of AC>A, D＞E at cooking water to rice ratios of 160% and 170%, above which A sample surpassed the rest of samples. 4. Sensory evaluation conducted by fifteen university students as panelists showed that there were more significant differences among five samples in flavour, texture than appearance and a notable preference for b and C over A, D and E.

• International Journal of Air-Conditioning and Refrigeration
• /
• v.9 no.2
• /
• pp.19-27
• /
• 2001

In the present study, the effects of film Reynolds number (60∼200) and volumetric content of non-absorbable gases (0∼10%) in water vapor on the absorption process of aqueous LiBr solution were investigated experimentally. The formation of solution film on the horizontal tubes of six rows was observed to be complete for Re>100. Transition film Reynolds number was found to exist above which the Nusselt number and Schmidt number diminishes with solution flow rate. As the concentration of non-absorbable gases increased, mass transfer rate decreased more seriously than heat transfer rate did. the degradation effects of non-absorbable gases seemed to be significant especially when small amount of non-absorbable gases was introduced to the pure water vapor.

• Korean journal of food and cookery science
• /
• v.27 no.6
• /
• pp.735-743
• /
• 2011

This study examined physicochemical properties of rice grains and qualities of cooked white rice of the high yielding, Japonica type, specifically Druryechanbyeo and Boramchanbyeo, and of the Tongil-type, specifically Hanarumbyeo and Andabyeo. The changes of water absorption rate of rice grains, their textural properties and a sensory evaluation of the cooked rice s were analyzed. All varieties were short grain. The length and width of Tongil type rice grains larger than those of Japonica type. The water absorption of white rice grains increased rapidly until 1 hr when soaking and after that increased slightly. The water absorption of Druryechan grain was higher than that of the Boramchan. The sensory evaluation results showed that the Japonica type cooked rices had a higher value for overall quality than the Tongil type cooked rices. With regard to the textural properties of the cooked rices, the hardness of Boramchan and Hanarum varieties showed higher than that of Druyechan and Anda varieties. Adhesiveness, springiness and chewiness were not significantly different between varieties (p<0.05).

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.4 no.3
• /
• pp.276-283
• /
• 2016

Red mud is an inorganic by-product produced from the mineral processing of alumina from Bauxite ores. the development of alkali-activated slag-red mud cement can be a representative study aimed at recycling the strong alkali of the red mud as a construction material. This study is to investigate the optimum water content, compressive strength, moisture absorption coefficient and efflorescence of alkali-activated slag-red mud soil pavement according to the recycling fine aggregate content. The results showed that the optimum water content, moisture absorption coefficient and efflorescence area of alkali-activated slag-red mud soil pavement increased but the compressive strength of that decreased as the recycled fine aggregate content increased.

• Clean Technology
• /
• v.7 no.2
• /
• pp.151-159
• /
• 2001

Mathematical modeling and numerical simulation studies have been conducted for a falling film type absorber of the ammonia absorption heat pump. A rigorous absorber model has been developed by considering temperature effects on physical properties and its predictability proved far superior to that of existing models, which has been confirmed by the experimental data. Using the developed model, effects of cooling water condition - temperature and flow rate - on the efficiency of absorber has been examined. As the result of simulation, the efficiency of absorber has increased as the cooling water temperature has decreased and flow rate has increased.