• Tribology and Lubricants
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• v.16 no.5
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• pp.332-340
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• 2000

The reduction of sulfur content in the diesel fuel has caused the poor lubricity of diesel fuel in the distributor type injection pumps of diesel engines that use the diesel for lubrication of their moving parts. To investigate the reason for poor lubricity of low sulfur diesel fuels, the wear scar diameters by HFRR (High Frequency Reciprocating Rig) were measured on the diesel fuels from Korean markets and the results were compared with their physical and chemical properties. Also, the lubricity change and the improvement effects on lubricity additives for the ultra low sulfur diesel fuel, were made experimentally, that will be regulated to a maximum of 0.005 wt% from about 2005 were evaluated. As a result, a good correlation was found between the wear scar diameter and the polyaromatic compound which includes heterocyclic compound in the diesel fuel. It was also found that the content of polyaromatic compound including heterocyclic compound was affected by the amount of desulfurization treatment fraction. And the lubricity additives with ester base were more effective than that with acid base on the ultra low sulfur diesel fuel. Therefore, it is suggested that the factors affecting the lubricity stated above should be taken into account to improve the lubricity property of the diesel fuel in the refining process.

• Food Science and Biotechnology
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• v.16 no.1
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• pp.1-7
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• 2007

Garlic (Allium sativum L.) contains a specific sulfur compound, the S-allyl derivative of L-cysteine sulfoxide, and has long been known for its antimicrobial activity against various microorganisms, including bacteria, fungi, and protozoa. The principal antimicrobial compound of garlic is S-allyl-L-propenethiosulfinate (allicin) which is generated by an enzyme, alliinase (L-cysteine sulfoxide lyase), from S-allyl-L-cysteine sulfoxide (alliin). This compound exists exclusively in Allium as a major non-protein sulfur-containing amino acid. S-Allyl-L-propenethiosulfinate belongs to the chemical group of thiosulfinates and is a highly potent antimicrobial. The potency of garlic extract is reduced during storage since thiosulfinates are unstable and are degraded to other compounds some of which do not have antimicrobial activity. Diallyl polysulfides and ajoene are sulfur compounds derived from allicin that do possess antimicrobial activity. It was recently found that garlic becomes antimicrobial on heating at cooking temperatures, and that the compound responsible for this is allyl alcohol, which is generated from alliin by thermal degradation.

• Food Science and Biotechnology
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• v.18 no.3
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• pp.771-775
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• 2009

Antimicrobial activity of garlic (pH 6.0) heated at $120^{\circ}C$ reached its maximum at 45 min of heating and maintained the level for the rest of heating time (300 min) when tested against Candida utilis ATCC42416. The principal antimicrobial compound was allyl alcohol (AA), a highly volatile compound without sulfur in its molecule. The concentration of AA in heated garlic gradually increased to over 2,000 ppm for the first 90 min and stayed at the level without appreciable changes in spite of further heating. Other antimicrobial compounds secondary to AA were lowly volatile sulfur compounds including diallyl polysulfides (diallyl trisulfide, diallyl tetrasulfide, and diallyl pentasulfide) and heterocyclic sulfur compounds (4-methyl-1,2,3-trithiolane, 5-methyl-1,2,3,4-tetrathiane, and 6-methyl-1,2,3,4,5-pentathiepane). When the pH of the garlic extract was lowered before heating, considerably more secondary antimicrobial sulfur compounds were formed and the antimicrobial activity was stronger than the pH unadjusted garlic. Lowly volatile sulfur compounds contributed a significant part of antimicrobial activity of heated garlic only during the early period (45-120 min) of heating regardless of pH treatment.

• Elastomers and Composites
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• v.56 no.4
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• pp.223-233
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• 2021

In this study, epoxidized liquid isoprene rubber (E-LqIR) was used as a processing aid in a silica-filled natural rubber compound to improve the fuel efficiency, abrasion resistance, and oil migration problems of truck and bus radial tire tread. The wear resistance, fuel efficiency, and extraction resistance of the compound were evaluated according to the molecular weight of E-LqIR. Results of the evaluation showed that the E-LqIR compound had a lower chemical crosslink density than that of a treated distillate aromatic extract (TDAE) oil compound because of the sulfur consumption of E-LqIR. However, the filler-rubber interaction improved because of the reaction of E-LqIR with silica and crosslink with the base rubber by sulfur. As the molecular weight of E-LqIR increased, crosslink with sulfur was facilitated, and the filler-rubber interaction improved, resulting in improved abrasion resistance. The fuel efficiency performance of the E-LqIR compound was poorer than that of the TDAE oil compound because of the low chemical crosslink density and hysteresis loss at the free chain end of E-LqIR. However, the fuel efficiency performance improved as the molecular weight of E-LqIR increased.

• Journal of The Korean Society of Grassland and Forage Science
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• v.8 no.3
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• pp.152-157
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• 1988

The effect of gypsum application was tested on dry matter yield, sulfur uptaken, composition of Ritrogen compound and sulhr compound and sulfur balance in mixed pasture. Total dry matter yields and sulfur uptake by grasses increased with the increasing of gypsum application rates. The ratios between total nitrogen and total sulfur in masses decreased with the increase of sulfur uptake at 2nd and 3rd cutting times. Cysteine content was little affected by gypsum while methionine content slightly increased an 4.0, 6.0 kg3 per 10a levels at 2nd and 3rd cutting times. The uptake of nitrate nitrogen decreased with gypsum application and dry matter digestibility increased about 1.1 to 3.3%. The soil pHs after experiment become high in surface and subsoil till 6.0 kg.S per 10a, but low at 10.0 kg.S per 10a. The content of sulfur in surface soil was 19.9 ppm after experiment, but very high in subsoi1,ranging from 94 to 143 ppm.S. Sulfur leached from the surface soil by 0.69, 2.39, and 6.24 kg.S per 10a in the plots of 4.0, 6.0, and 10.0 kg.S per 10a, respectively.

• Polymer(Korea)
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• v.39 no.2
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• pp.240-246
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• 2015

Formation of a strong 3-dimensional interfacial network structure via chemical reaction between hydroxyl group on silica surface and NR chain by the addition of bis(triethoxysilylpropyl)tetrasulfide (TESPT) into silica-filled NR compound was observed by using Py-GC/MS and SEM. Addition of TESPT into silica-filled NR compound decreased scorch time ($t_{10}$) due to increased sulfur content, and reduced cure rate index (CRI) via continuous reaction between sulfur atoms in TESPT, which acted as a sulfur donor, and activators and/or accelerators. Addition of TESPT in the compound improved processability and mechanical properties of the compound. Overall, we observed that the addition of TESPT into the silica-filled NR compound formed a silica-TESPT-NR network, and thus the degree of crosslinking was increased resulting in improved mechanical properties.

• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.5
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• pp.548-557
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• 2015

This paper is results on Chemisorption of organic compound for the sea water fire fighting line of naval vessels. The quantitative analysis of Chemisorption has been investigated in seawater after immersion in 0.1 % of NaDDTC solutions for 43 hours. The morphology and topography were investigated by FE-SEM and AFM. The chemical elements were analyzed by SEM-EDS, XPS and the depth of chemical elements was measured by depth profiles. The effect of NaDDTC comes from Chemisorption between Copper and Sulfur of NaDDTC. As a result, test results showed that sulfur is helpful to protect a corrosion of seawater line.

• Elastomers and Composites
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• v.33 no.4
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• pp.274-280
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• 1998

Order of reaction, rate constant, activation energy for vulcanization reaction, crosslinking density, and elastic constant of the network produced by sulfur curing were investigated on the SBR/BR blends containing silica and carbon black under same cure system. The reaction order was shown to be first order regardless of filler types. The carbon black filled rubber compounds showed higher rate constant compared to silica filled compounds. But activation energy appeared to be same regardless of filler type and rubber blend ratio. The crosslinking density and elastic constant is higher in the carbon black filled compound compared to silica filled compounds because of strong interaction between rubber and carbon black. On the other hand, crosslinking density and elastic constant were decreased with increasing the butadine rubber content in rubber blends. From the comparison of combined sulfur content in the vulcanized rubber, sulfur content in the silica filled compound become constant 20min later after reaction initiates but sulfur content in the carbon black filled compound become constant 10min later after reaction starts. The silica compound has a longer induction time ($t_2$) and optimum cure time($t_{90}$) compared to those of the carbon black filled compound.

• Korean journal of food and cookery science
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• v.19 no.1
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• pp.17-23
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• 2003

This study was performed to find the changes in volatile sulfur compounds of garlic under various storage conditions. The volatile sulfur compounds of garlic were identified with GC and GC/MS. Analysis on the detected volatile sulfur compound of garlic which is known to have medical effect was performed while storing for two days at room temperature and for 1, 3 and 7 days at 4$^{\circ}C$ and -18$^{\circ}C$, respectively. The results of the study were summarized as follows : Total amount of 7 volatile sulfur compounds was the highest in the sample stored at room temperature for one hour. During the storage of 1, 3 and 7 days at -18$^{\circ}C$, chopped garlic contained more of volatile sulfur compounds than under any other storage conditions and the amounts of 7 volatile sulfur compounds increased gradually during the storage of chopped garlic.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.8
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• pp.2935-2941
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• 2010

This study used 3 kinds of experimental toothpaste with different contents(0%, 1.1%,2.2% of SLS. A total of 150 young adults in their 20's without any systemic disease were recruited for the study. These 150 subjects were subdivided into three groups(each having 50 subjects) according to the results of preliminary oral examination.After 4 weeks application of the three groups of toothpaste, Group C showed the highest halitosis index, followed by Groups A and B which had similar halitosis indices. Both oral sulfur compound and aerobic sulfur compound were measured at high content possibly because higher SLS content which is associated with the lower salivary flow rate is causing the xerostomia. SLS content was correlated with oral sulfur compound (r=0.412) and aerobic sulfur compound (r=0.285).