• Applied Chemistry for Engineering
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• v.19 no.1
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• pp.51-58
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• 2008

A series of oleic acid esters containing mercaptobenzothiazole and dialkylenedithiocarbamate, which are potential environmentally friendly lubricating grease additives, were synthesized as 90% yield through several method such as nucleophilic substitution of dialkyl amine and carbon disulfide, reduction reaction, and condensation reaction. The structures of the additives were confirmed by $^1H$-NMR, FT-IR and EA analysis. The additives (1 wt%) were soluble in 100 N BO except C4-DTC-OE and soluble in soybean oil. The tribological properties as lubricating additives in 100 N BO were evaluated using 4-ball tester and the results showed as follows: Bz-thia-OE < C4-DTC-OE < Pyrro-DTC-OE < C8-DTC-OE. Whereas, the 4-ball anti-wear properties were not shown in soybean oil.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.10
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• pp.386-392
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• 2020

The self-weight of the 3D printing concrete increases with increasing printing height. Therefore, the lower layer must be hardened within a suitable time to secure continuous printing performance. In particular, the hardening speed of concrete is slow in the winter season when the temperature was low. Hence, the early strength of 3D printing concrete requires improvement. In domestic and international literature, cases of increasing the early strength of concrete using inorganic chemical additives, such as amine-based, nitrate-based, sodium-based, and calcium-based, have been reported. In this study, early strength improvement-type additive samples (amine-based, nitrate-based, sodium-based) were prepared, and their performance was evaluated. When using a nitrate-based additive, the early strength was increased significantly in a 10 ℃ environment. In addition, it was possible to secure a higher early strength than the existing 3D printing concrete mixed at 20 ℃.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2471-2475
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• 2007

Clathrate compound is the material that host in hydrogen bond forms cage and guest is included into it and combined. Crystallization of hydrate is generated at higher temperature than that of ice from pure water. And physical properties according to temperature are stable and congruent melting phenomenon is occurred without phase separation. But clathrate compound still had supercooling problem occurred in the course of phase change and supercooling should be minimized because it affects efficiency of equipment very much. Therefore, various studies on additives to restrain this or heat storage methods are needed. In this study was investigated the cooling characteristics of the TMA-water clathrate compound including TMA (Tri-methyl-amine, $(CH_3)_3N)$ of 20${\sim}$25 wt% as a low temperature latent heat storage material. And ethanol$(CH_3CH_2OH)$ was added and its cooling characteristics were studied experimentally to restrain supercooling of TMA-water clathrate compound.

• International Journal of Fluid Machinery and Systems
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• v.4 no.2
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• pp.223-228
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• 2011

The performance characteristics of centrifugal pump were measured experimentally when running with tap water and drag-reducing surfactant (Octadecyl dimethyl amine oxide (OB-8)) solutions. Tests have been performed on five cases of surfactant solutions with different concentrations (0ppm (tap water), 200ppm, 500ppm, 900ppm and 1500ppm) and four different rotating speeds of pump (1500rpm, 2000rpm, 2500rpm and 2900rpm). Compared with tap water case, the experimental results show that the total pump heads for surfactant solution cases are higher. And the pump efficiency with surfactant solutions also increases, but the shaft power for surfactant solutions cases decreases compared to t hat for tap water. There exists an optimal temperature for surfactant solutions, which maximizes the pump efficiency.

• Bulletin of the Korean Chemical Society
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• v.32 no.7
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• pp.2227-2232
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• 2011

The new metrology, Advanced Poly-silicon Ultra-Trace Profiling (APUTP), was developed for measuring bulk Cu and Ni in heavily boron-doped silicon wafers. A Ni recovery yield of 98.8% and a Cu recovery yield of 96.0% were achieved by optimizing the vapor phase etching and the wafer surface scanning conditions, following capture of Cu and Ni by the poly-silicon layer. A lower limit of detection (LOD) than previous techniques could be achieved using the mixture vapor etching method. This method can be used to indicate the amount of Cu and Ni resulting from bulk contamination in heavily boron-doped silicon wafers during wafer manufacturing. It was found that a higher degree of bulk Ni contamination arose during alkaline etching of heavily boron-doped silicon wafers compared with lightly boron-doped silicon wafers. In addition, it was proven that bulk Cu contamination was easily introduced in the heavily boron-doped silicon wafer by polishing the wafer with a slurry containing Cu in the presence of amine additives.

• Journal of Korean Society of Transportation
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• v.8 no.2
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• pp.119-131
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• 1990

Physico-chemical properties of asphalt, aggregate, and asphalt-aggregate mixture that might influence stripping were summarized in Table 1, based on the fundamental theories concerning stripping. It was found that although physical properties of aggregate affected stripping, there was no strong correlation between the physical properties of aggregate, such as pore volume and surface area, and the stripping propensity of the aggregate. Chemical and electrochemical properties of aggregate surface in the presence of water were most important factors for stripping. All mineral aggregates tested in this study imparted distinctive pH values to the contacting water and possessed distinctive electrochemical properties as measured by zeta potential. It was found that aggregates which had relatively higher surface potential in water and/or which imparted relatively higher pH to the contacting water were more susceptible to stripping. The functionalities contained in antistripping additives tested were primary and secondary amines and those of organic nitrogen compounds. The functionalities were determined by examining their infrared spectra. Based on the interfacial energy concept, the contact angle of an asphalt drop on an aggregate surface immersed in water related to the stripping propensity. The contact angle and stripping propensity were markedly reduced by the presence of an antistripping additive. In general, all the additives tested improved stripping resistance to some extent, depending on their concentration in the asphalts. The optimum dosage of an additive varied with different asphalts, as well as different aggregates. All antistripping additives tested in this study lost their effectiveness and failed to function to some extent when maintained for hours in a hot asphalt.

• Journal of the Korean Wood Science and Technology
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• v.46 no.5
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• pp.449-470
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• 2018

A review of research trends on wood surface protection for exterior use obtained the following conclusions: It has been reported that inorganic compounds such as chrome and copper used as wood preservatives can protect wood from weathering. It has been shown that precoating with hydrophobic substances such as wax and oil, UV absorbers, and HALS (Hindered Amine Light Stabilizers) enhances weathering resistance on the surface of ACQ-treated wood. Opaque coatings of paint/stains and semitransparent stains on the surface of preservative treated wood can increase the synergistic effects on prevention of weathering deterioration. Also the need for repainting periodically for the protection of the preservative treated wood surface has also been suggested. ZnO or $TiO_2$ of fine particles, metal ions such as Co, Cr, Fe, Mn, Ni and Ti, and UV absorbers such as tris-resorcinol triazine derivatives, triazine and benzotriazole were introduced as additives for preventing UV in the transparent coating on wood. Several reports showed that chemical modification such as methylation, acetylation, or alkylations have made some increases the effects of preventing weathering with the increasing weight gain of chemical formulas. In heat-treated wood, there were various contradictory reports on the resistance of weathering, and there were some other reports emphasizing the necessity of painting with UV resistance, which leads to the necessity of more advanced studies.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.6
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• pp.804-811
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• 2013

The effects and significance of ${\gamma}$-amino butyric acid (GABA) producing bacteria (GPB) on in vitro rumen fermentation and reduction of biogenic amines (histamine, methylamine, ethylamine, and tyramine) using corn meal as a substrate were determined. Ruminal samples collected from ruminally fistulated Holstein cows served as inoculum and corn was used as substrate at 2% dry matter (DM). Different inclusion rates of GPB and GABA were evaluated. After incubation, addition of GPB had no significant effect on in vitro fermentation pH and total gas production, but significantly increased the ammonia nitrogen ($NH_3$-N) concentration and reduced the total biogenic amines production (p<0.05). Furthermore, antioxidation activity was improved as indicated by the significantly higher concentration of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) among treated samples when compared to the control (p<0.05). Additionally, 0.2% GPB was established as the optimum inclusion level. Taken together, these results suggest the potential of utilizing GPB as feed additives to improve growth performance in ruminants by reducing biogenic amines and increasing anti-oxidation.

• Corrosion Science and Technology
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• v.3 no.3
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• pp.112-117
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• 2004

This work investigated the material properties of Ni-P-B alloy electrodeposits obtained from a Ni sulfamate bath as a function of the contents of the P and B sources($H_3PO_3$ and dimethyl amine borane complex(DMAB), respectively) with/without additives. Chemical composition, residual stress, microstructure and micro hardness were investigated using ICP(inductively coupled plasma) mass spectrometer, flexible strip, XRD, TEM and micro Vickers hardness tester, respectively. From the results of the compositional analysis, it was observed that P and B are incorporated competitively during the electrodeposition and the sulfur from the additive is codeposited into the electrodeposit. The measured residual stress value increased in the order of Ni, Ni-P, Ni-B and Ni-P-B electrodeposits indicating that boron affects the residual tensile stress greater than phosphorus. As the contents of the alloying element sources of P and B increased, crystallinity and the grain size of the electrodeposit decreased. The effect of boron on crystallinity and grain size was also relatively larger than the phosphorus. It can be explained that the boron with a smaller atomic radius contributes to the increase of residual stress in the tensile direction and the larger restraining force against the grain growth more significantly than the phosphorus with a larger atomic radius. Introduction of an additive into the bath retarded crystallization and grain growth, which may be attributed to the change of the grain growth kinetics induced by the additive adsorbed on the substrate and electrodeposit surfaces during electrodeposition.

• Journal of Adhesion and Interface
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• v.10 no.4
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• pp.182-190
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• 2009

In this work, effect of antistrip additives to reduce moisture damage of asphalt mixture were studied. Asphalt antistripping agents were prepared by condensation of formaldehyde with tetraethylene pentamine (TEPA), triethylenetetramine (TETA) and bis(hexamethylene)-triamine (BHMT), respectively. And also the metal type antistripping agent was prepatred by neutralization of stearic acid or palmitic acid with metal hydroxide. Mechanical characteristics of the asphalt mixture added antistripping agent were evaluated with Marshall stability, submerging residuals and coating rate. It was found that antistripping agent prepared in this study reduced moisture damages of asphalt mixtures. In particular, asphalt mixtures added BHMT and C/S (Calcium stearate hydroxide) antistripping agent showed highest submerging and coating rate. Because BHMT and C/S type antistripping agent was to improve bonding between asphalt and aggregate owing to increase of amine concentration and role of metal surfactant.