• International Journal of Highway Engineering
• /
• v.15 no.2
• /
• pp.57-63
• /
• 2013

PURPOSES : This study was performed to investigate a feasibility of job-site use of recycled concrete aggregate exceeding 3% of absorption rate. Test variables are coarse aggregate types such as natural aggregate, job-site processed recycled aggregate, and recycled aggregate processed from the intermediate waste treatment company. METHODS : First, aggregate properties such as gradation, specific gravity and absorption rate were determined. Next a basic series of mechanical properties of concrete was tested. RESULTS : All strength test results such as compression, flexure and modulus were satisfied for the minimum requirements. Finally up to first 48 elapsed days the shrinkage strains of concretes made from both recycled aggregates (in case of volume-surface ratio of 300) appeared to be greater than 26% of the companion concretes made from natural aggregates. CONCLUSIONS : Drying shrinkage result is ascribed to greater absorption rate and specific gravity of those specimens made from recycled aggregate. This may be reduced with an addition of admixtures.

• Journal of Ginseng Research
• /
• v.17 no.3
• /
• pp.224-227
• /
• 1993

Weight (g/root) and bulk density (g/$cm^3$) of tap root in 15-root-grade of 4-year-old white ginseng were investigated by specific gravity and weight-volume method. Bulk density measured by specific gravity ranged from 0.8 to 1.2g/$cm^3$ with almost normal distribution in frequency (number 1 of roots). Bulk density measured by volume-weight method had significant correlation with root weight. The percentage of high bulk density root (above 1.0) showed significant positive correlation with mean root weight or mean bulk density of root weight, indicating that the growth conditions for large root provide the better compactnes of root tissue.

• Journal of the Korean Ceramic Society
• /
• v.45 no.1
• /
• pp.54-59
• /
• 2008

Hydrated sodium silicate with 25 wt% water contents was synthesized by hydrothermal reaction using anhydrous sodium silicate. The hydrated sodium silicate was expanded at $370^{\circ}C$ for 30 min. and then pulverized, classified (- 200 mesh) and press-formed. The samples were heat treated at $400{\sim}900^{\circ}C$ for 30 min. in order to study the expansion characteristics depending on heat treatment temperature. A porous body with closed pore was formed above $600^{\circ}C$. The volume expansion ratio and the pore size were increased and the specific gravity was decreased with increasing heat treatment temperature. However, the volume expansion ratio was decreased and the specific gravity was increased above $850^{\circ}C$ due to the softening of the sodium silicate.

• Geomechanics and Engineering
• /
• v.17 no.2
• /
• pp.157-164
• /
• 2019

The effect of electrochemical modification of the physical and mechanical properties of sandstone from Paleozoic coal measure strata was investigated by means of liquid nitrogen physical adsorption, X-ray diffraction and uniaxial compressive strength (UCS) tests using purified water, 1 mol/L NaCl, 1 mol/L $CaCl_2$ and 1 mol/L $AlCl_3$ aqueous solution as electrolytes. Electrochemical corrosion of electrodes and wire leads occurred mainly in the anodic zone. After electrochemical modification, pore morphology showed little change in distribution, decrease in total pore specific surface area and volume, and increased average pore diameter. The total pore specific surface area in the anodic zone was greater than in the cathodic zone, but total pore volume was less. Mineralogical composition was unchanged by the modification. Changes in UCS were caused by a number of factors, including corrosion, weakening by aqueous solutions, and electrochemical cementation, and electrochemical cementation stronger than corrosion and weakening by aqueous solutions.

• Journal of Korea Foundry Society
• /
• v.15 no.2
• /
• pp.184-193
• /
• 1995

Effects of process parameters during thixocasting, such as solid volume fraction, mold temperature and extrusion ratio, on the mold filling behaviour and fluidity of Mg alloy(AZ91D) have been investigated. The semi-solid ingot held for 60 minutes at the semi-solid temperature range did not contain the equilibrium volume fraction of solid as expected from the phase diagram. Therefore, in order to obtain the desired solid fractions, and to suppress the exaggerated grain growth during heating, it was required to heat the ingot rapidly up to the temperature $10^{\circ}C$ higher than the semi-solid temperature suggested from the phase diagram for a specific volume fraction of solid. The experimental results show that mold filling behaviour and fluidity can be improved with the use of the higher mold temperature and the lower volume fraction of solid, but remain nearly unaffected by the change of extrusion ratio.

• International Journal of CAD/CAM
• /
• v.6 no.1
• /
• pp.193-198
• /
• 2006

Plunge milling is the fastest way to mill away large volumes of metal in the axial direction. The residual volume (inaccessible volume by the plungers) is minimized when selecting a specific direction of filling. This direction is known as the optimal inclination angle for filling of the plunged area. This paper proposes a new algorithm to calculate the optimal inclination angle of filling and to fill the plunged area with multi-plungers sizes. The proposed algorithm uses the geometry of the 2D area of the shape that being cutting to estimate the optimal inclination angle of filling. It is found that, the optimal inclination angle for filling of the plunged area is the same direction as the longer width of the equivalent convex polygon of the boundary contour. The results of the tested examples show that, the residual volume is minimized when comparing the proposed algorithm with the previous method.

• The Korean Journal of Food And Nutrition
• /
• v.28 no.6
• /
• pp.1011-1018
• /
• 2015

The effects of mixing speed (3, 6 and 10 speed) and time (2, 5 and 10 min) on the dynamic viscoelasticity of dough and the baking properties of gluten-free rice bread were investigated. The specific gravity of the dough was not affected by the mixing speed and time before and after fermentation. The elasticity (G') and viscosity (G") of the dough increased and the tan ${\delta}$ (G"/G') decreased with higher mixing speeds and longer mixing times. The specific volume of the gluten-free rice bread was affected by the mixing time in response surface methodology (RSM). The hardness of the gluten-free rice bread showed a decreasing trend as the specific volume for the gluten-free rice bread increased. The appearance of the gluten-free rice bread was symmetrical at high mixing speeds and long mixing times. Overall results indicated that the quality of gluten-free rice bread could be improved by controlling the mixing speeds and mixing times for the dough.

• Carbon letters
• /
• v.4 no.1
• /
• pp.31-35
• /
• 2003

The specific adsorption behaviors of activated carbons (ACs) treated with 30 wt% $H_3PO_4$ or NaOH were investigated in the removals of NO or $NH_3$. The acid and base values were determined by Boehm's titration method. And, the surface properties of ACs were studied by FT-IR and XPS analyses. Also, $N_2/77K$ adsorption isotherm characteristics, including the specific surface area and micropore volume were studied by BET and t-plot methods, respectively. From the adsorption tests of NO and $NH_3$, it was revealed in the case of acidic treatment on ACs that the $NH_3$ removal was more effective due to the increase of acidic functional groups in carbon surfaces. Also, the NO removal was increased, in the case of basic treatment, due to the improvement of basic functional groups, in spite of significant decreases of BET's specific surface area and total pore volume. It was found that the adsorption capacity of ACs was not only determined by the textural characteristics but also correlated with the surface functional groups in the acid-base intermolecular interactions.

• Journal of radiological science and technology
• /
• v.38 no.4
• /
• pp.437-442
• /
• 2015

Accurate volume measurement of the prostate is a significant role in determining the result of diagnosis and treatment of benign prostate hyperplasia. The purpose of this study was to determine, when measuring prostate volume by TRUS, whether location is more accurately determined by transaxial or longitudinal scanning. With reference to the patient's image, it was produced six prostate model. It compares the actual volume and the measurement volume, and find the optimal measurement position of each specific model. Prostate volume measured by TRUS closely correlates with prostate phantom volume. There was no significant difference(p = .156). To measure the accurate volume of prostate with focal protrusion, its length should be measured exclude the protrusions.

• Journal of radiological science and technology
• /
• v.33 no.3
• /
• pp.239-243
• /
• 2010

Even though clinical use DRE, PSA and TRUS for screening while diagnosing prostate cancer early, however, we cannot achieve to diagnose it accurately by one method. Thus, mutual supplements are strongly required in diagnosis. It means that we should identify relationship between prostate volume and serum PSA under different ages for better diagnosis. The subjects(405 men) visited the department of diagnostic radiology in a general university hospital from January 2008 to December 2008, who was going to take the prostatic evaluation by TRUS. 13 men, who did definite diagnosis of prostate cancer before through biopsy, were excluded in this study. All data were expressed as mean and standard deviations by using SPSS 14.0 package programs and were analyzed by using one-way ANOVA to evaluate the effect of different ages. And Scheffe Post hoc comparison is accomplished in order to make significant difference in prostate volume, PSA and PSAD according to ages. Pearson correlation was used for ages, prostate volume, PSA and PSAD. According to examination, the subjects' prostate volume and serum PSA level increase as person's age. We can see significant difference between group over 70 years and group from 40 and 50 years. Moreover, age, prostate volume and serum PSA have significant positive correlation. Even though we can get variations in serum PSA level by changing prostate volume according to ages, it is worthwhile to mention that more strong association for prostate volume is observed than ages in elevation of serum PSA. Therefore, it is strongly recommended to consider prostate volume weightly when it comes to evaluate for men with elevated PSA level. Finally, TRUS is an excellent extra equipment to diagnose prostate cancer because it can contribute to early diagnose and pertinent treatment of prostate cancer.