• Korean Journal of Veterinary Research
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• v.55 no.1
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• pp.13-20
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• 2015

This study was performed to investigate the antibacterial, antioxidant, and termite repellent effects of citronella oil (CiO) and lemongrass oil (LO). When the antibacterial activity against Staphylococcus (S.) aureus with various levels of antibacterial resistance were tested, a 0.05% concentration of CiO and LO completely inhibited the growth of all tested S. aureus strains. Evaluation of the antioxidant effect demonstrated that the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of CiO was 2~3 times greater than that of LO. Among trial products made with various combinations of CiO and LO, a CiO : LO ratio of 6 : 4 had the most potent termite repellent effects. Assessment of acute toxicity of the trial product showed that the $LD_{50}$ was more than 2,000 mg/kg. Based on the above results, CiO and LO have antibacterial, antioxidant, and termite repellent activities. Therefore, both compounds could be potential termites repellent reagents.

• Journal of the Korean Home Economics Association
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• v.35 no.3
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• pp.275-286
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• 1997

The effects of water-and oil-repellent finishes on the surface characteristics of polyester fabrics were investigated in this study. Three kinds of fluoropolyment were selected as water=and oil-repellent finishing agents. The effects of water-and oil-repellent finishes were determined by the water repellency and oil repellency. The surface properties of untreated and treated polyester fabrics were evaluated with respects to crease resistance, contact angle and wicking time. The results of this study were as follows: 1. The polyester fabrics treated with fluoropolymers showed much higher water repellency and oil repellency than those of untreated polyester fabrics. Water-and oil-repellency of fabrics were increased with the crystallinity and the hydrophobic-hydrophillic components of fluoropolymers. 2. Water repellency of fabrics treated with fluoropolymer with hydrophobic components was the highest. Oil repellency of fabrics treated with fluoropolymer with high crystallinity was the highest. Water-and oil-repellency of fabrics treated with fluoropolymer with hydrophyllic components was low comparatively. 3. The crease resistance of polyester fabrics treated with fluoropolymer nearly approached to that of untreated polyester fabric. 4. The water-and oil-repellent finishes improved contact angle markedly. Especially the contact angle of ployester fabric treated with fluropolymer with hydrophobic component was the biggest. 5. The wicking time of polyester fabric treated with fluropolymer with hydrophobic component was the longest.

• Korean Journal of Veterinary Research
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• v.2 no.2
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• pp.15-24
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• 1962

In the previous report it was demonstrated that aqueous extracts of two Korean indigenous crude drugs, Radix Jingyu and Fructus ponciri, have an excellent tick repellent effect, and also the need for further analytical study of these crude drugs was suggested. In the experiments to be reported herein, attempts were made to find out the active ingredients from Radix Jingyu, since the aqueons extract of Radix Jingyu proved to be mone effective than that of Fructus ponciri. It will be shown that the active ingredient is indicative of Lycaconitine, a known alkaloid. An aqueons solution containing 1.5 Gms of Lycaconitine in tartrate when sprayed on a cow exerted tick repellent effect against Boophilus microplus which lasted approximately 25 days without any harmful influences on cattle. It will also be shown that the oil-fat components of Radix Jingyu act synergistically with Lycaconitine in accelerating and lengthening the effect, although the components alone have no effect under the conditions tested. It was of interest to note that the oil-fat components of Radix Jingyu showed definite repellent effect against the larvae of Boophilus microplus in laboratory experiments by the method newly devised. On the basis of these observations, it was concluded that Lycaconitine can be used as cattle tick repellent, and the evidence seems to warrant a large scale production of Lycaconitine for its widespread use. Further studies on the possible effect of the alkaloid on other genera or species of ticks and related vermins were also indicated.

• Magazine of the Korea Concrete Institute
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• v.9 no.2
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• pp.137-144
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• 1997

The effcct of specific g~avity cont~olled In the .range fiom O.4 to 0.7 by particle size and added amount of A1 powder in the presence or absence of water repellent agent on the physical properties of ALC was examined to evaluate frost resistance and durability. The compressive sttcngth and the tensile strength are increased and independency with water repellent agent when the specific gravity is increased in the range from 0.4 to 0.7. According as the added amount of water repellent agent was increased. frost resistance was improved and absorption ratio was decreased. ALC produced from fine Al powder has a low volume reduction by scaling and a sound apperance after freezing/thawing test and top surface freezing test.

• Computers and Concrete
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• v.34 no.1
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• pp.123-135
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• 2024

Strain-hardening cement-based composites (SHCC) under cracked condition exhibits remarkable capillary absorption due to water ingress from multiple cracks. Surface treatment using water repellent agents is an effective way for improving water resistance of SHCC, but the water resistance may remarkably decrease when cracks penetrate impregnation depth. Another way is to add water repellent agents directly into the mixture, offering SHCC integral water repellency even if cracks form later. However, although integral water repellent treatment has been proved feasible by previous studies, there is still lack of simulation work on the treated SHCC for evaluating its durability. This study presents a simulation method for capillary absorption of cracked SHCC with integral treatment based on a multi-scale approach proposed in the authors' previous work. The approach deals with water flows in bulk matrix and multiple cracks using two individual transport equations, respectively, whereas water absorbed from a crack to its adjacent matrix is treated as the mass exchange of the two equations. In this study, the approach is enhanced for the treated SHCC by integrating the influencing of water repellency into the two transport equations as well as the mass exchange term. Using the enhanced approach, capillary absorption of water repellent SHCC under cracked condition is simulated, showing much more reduced water ingress than the untreated concrete, which is consistent with total absorption data from previous tests. This approach is also capable of simulating water spatial distribution with time in treated SHCC reasonably.

• Journal of the Korean Society of Clothing and Textiles
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• v.21 no.1
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• pp.3-9
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• 1997

From the standpoint of end-use and practical performances, attention was focused preparing cotton fabrics which posses good dyeability as well as water repellency. The results are summarized as follows, as far as findings obtained from this study is concerned. The fluoro chemical (FC) water repellent finished cotton fabrics exhibited good dyeing properties and colorfastness to washing. Furthermore, the DMDHEU durable-press and FC water repellent finishes in a single pad bath resulted in excellent durable press performance and good water repellency.

• Natural Product Sciences
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• v.5 no.2
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• pp.104-106
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• 1999

The chloroform fraction of the aqueous extract of the fresh leaves of Vitex negundo by bioactivity guided isolation yielded a pure compound, rotundial (1) which has shown potent mosquito repellent activity. Using spectral data (UV, IR, $^1H\;&\;^{13}C$ NMR and MS) its structure has been elucidated.

• Journal of the Korean Applied Science and Technology
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• v.5 no.1
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• pp.63-70
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• 1988

The quaternized compound of the copolymer between 2-diethylaminoethyl methacrylate and stearyl methacrylate (DSACC) was chosen as the mother resin for the water repellent of acrylics. The quaternized compound of 1-lauroyl dis (amino ethyl)-2-dodecyl imidazoline (LDDIC) was used to promote softening effect and hydrostatic pressure for the water repellent. The water repellent (EDUWC) obtained from the DSACC and LDDIC blended with waxes and emulsifiers improved the properties such as the water repellency, washable, tear strength and crease recovery when it was treated on the nylon fabrics with and without the resin. The reaction mechanism between the Nylon fiber and EDLWC was examined, and EDLWC was confirmed as the durable water repellent.

• Proceedings of the KAIS Fall Conference
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• 2005.05a
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• pp.287-289
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• 2005

Repellent effcacies of two natural aroma compounds. citronella and citronellal, against mosquitoes were evaluated both in field and in vitro. In vitro, the experiment was conducted with three controlled bands impregnated with $30\%$ citronella extract, $15\%$ citronella extract and $30\%$ citronellal extract, and with band impregnated $30\%$ citronella in field. Raw data was obtained by the means of counting numbers bitten by mosquitoes per unit time, namely human bait method. Comparative repellent efficacies of above three controlled bands were calculated at $86\%$, $73\%$, and $78\%$, respectively in vitro, and $80\%$ in field, showing high repellent effectiveness against mosquitoes. This estimation was also confirmed by t-test compared between control group and each experimental group.

• Fire Science and Engineering
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• v.23 no.5
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• pp.196-205
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• 2009

Electric mosquito repellent mats can be ignited by damage of cables, partial disconnection, overload. tracking and so on. In this study, we examined the structure of mosquito repellent mat, positive temperature coefficient(PTC) thermistor, used for heating element and phenomenological characteristics of remains, obtained on the scene of fires. After reappearance ignition test of PTC thermistors, we did comparison analysis them. And we could confine that the feature of heating plate and the shape of bursting were same.