• Title/Summary/Keyword: colony elimination

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Monitoring of Termite in Haeinsa Temple and Control method (해인사의 흰개미 모니터링 및 방제 방안)

  • Jeong, So-Young;Lee, Kyu-Shik;Chung, Yong-Jae
    • 보존과학연구
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    • s.23
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    • pp.77-93
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    • 2002
  • There are several methods of pest control for the prevention of wooden cultural properties from damages caused by insects, especially termites. Those are as follows; physical control, chemical control, biological control, and integrated pest management. In Korea, we primarily use mvestigation of monitoring, fumigation, treatment of insecticidal and antiseptic chemicals, soil termiticide treatment, and termite colony elimination system. As damages by termites were detected at Eunghyanggak and Saundang of Haeinsa temple in June, 1998, we carried out monitoring with wooden device, in order to investigate damages of wooden building by termite and paths of termite invasion. According to the result of investigation of monitoring from1999 to 2002, we found that termites were inhabiting continually at forests around Haeinsa and that wooden buildings such as Saundang, Cheonghwadang were damaged by termites. So we thought that control methods such as soil termiticide treatment and termite colony elimination system would be effective. Especially, to investigate efficacy of termite colony elimination system, we carried out efficacy test of termite colony elimination system in Jongmyo during 17 months(2000.7.~2001.11.). The result of efficacy test showed that termite colony elimination system eliminated termite colonies gradually(over 12 months from installation of colony elimination system to elimination of termite colony).

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An Improved Phase-Shifted Carrier Pulse Width Modulation Based on the Artificial Bee Colony Algorithm for Cascaded H-Bridge Multilevel Inverters

  • Cai, Xinjian;Wu, Zhenxing;Li, Quanfeng;Wang, Shuxiu
    • Journal of Power Electronics
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    • v.16 no.2
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    • pp.512-521
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    • 2016
  • Cascaded H-bridge multilevel (CHBML) inverters usually include a large number of isolated dc-voltage sources. Some faults in the dc-voltage sources result in unequal cell dc voltages. Unfortunately, the conventional phase-shifted carrier (PSC) PWM method that is widely used for CHBML inverters cannot eliminate low frequency sideband harmonics when the cell dc voltages are not equal. This paper analyzes the principle of sideband harmonic elimination, and proposes an improved PSCPWM that can eliminate low frequency sideband harmonics under the condition of unequal dc voltages. In order to calculate the carrier phases, it is necessary to solve transcendental equations for low frequency sideband harmonic elimination. Therefore, an approach based on the artificial bee colony (ABC) algorithm is presented in this paper. The proposed PSCPWM method enhances the reliability of CHBML inverters. The proposed PSCPWM is not limited to CHBML inverters. It can also be applied to other types of multilevel inverters. Simulation and experimental result obtained from a prototype CHBML inverter verify the theoretical analysis and the achievements made in this paper.

Controlling Sacbrood Virus Disease in Apis cerana Colonies with Biological Methods in Korea

  • Vung, Nguyen Ngoc;Kim, Iksoo;Lee, Man Young;Kim, Hye Kyung;Kim, Dong Won;Choi, Yong Soo
    • Journal of Apiculture
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    • v.33 no.4
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    • pp.283-295
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    • 2018
  • As Sacbrood virus (SBV), a causative agent of larval death and colony collapse in Apis cerana honey bee, is prevalent and poses one of the most significant threats to the Korean apiculture, development of methods to counter this viral disease is urgently needed. In this study we tested some SBV controlling methods, such as requeen, shook swam, adding Apis mellifera and spraying yogurt to SBV inoculated colony. Colony size measured by number of sealed brood and adult were evaluated every 15 days until two months while instances of recurrence were recorded up to five months after applying treatment methods. We also test the effects of yogurt on healthy and SBV-infected larvae at both in vitro reared larvae and colony level. Our result showed that all SBV controlling methods had similar success rates with respect to elimination of SBV clinical symptom up to 30 days post treatment. Mix-species and spraying yogurt method had similar pattern of sealed brood and adult number and higher than that of other SBV controlling methods up to 45 days post treatment. These two groups also showed the lower percentage of SBV recurrence (50% and 66.7%) at 120 days post treatment than other group that mostly colony had clinical symptom. Result on in vitro reared larvae challenged with yogurt showed that yogurt have neither harmless on healthy larvae nor remedial effect on SBV infected larvae. However, at colony level, colony in group received yogurt treatment removed significantly more SBV-infected larvae, SBV-killed larvae, and even healthy larvae in comparison to the control, suggested that yogurt could trigger the hygienic behavior of nurse bee. Our results recommended that it is practical in beekeeping by adding A. mellifera and spraying yogurt to control SBV in A. cerana colony.

Development and culture optimization of mutants of Thiobacillus sp. IW for elimination of hydrogen sulfide

  • Kang, Sun-Chul;Lim, Kwang-Hee;Shin, Seung-Yong
    • 한국생물공학회:학술대회논문집
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    • 2005.10a
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    • pp.465-467
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    • 2005
  • UIW-10 mutant obtained by UV treatment using sulfur-oxidizing bacteria, Thiobacillus sp. IW was studied. The colony size of UIW-10 was found 2 $^{\sim}$ 3 times bigger in diameter than the parent colony on TAM medium. UIW-10 mutant growth was two times higher than parent strain at 6 h culture in liquid medium containing sulfides such as sulfur and sodium thiosulfate. Initial pH and temperature for the optimum growth of UIW-10 were 6.0 and $35-40^{\circ}C$, respectively. It was found that addition of 0.5% yeast extract and 0.5 to 2.0% tryptone as nitrogen sources and the constant agitation at 150 to 200 rpm had a positive effect and the growth of UIW-10 was increased.

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Study of the present situation on the termite control of wooden structures(I) - Focused on the case of US (목조건축물의 흰개미 방제에 대한 국외 현황조사(I) - 미국의 사례를 중심으로 -)

  • Jeong, So Young
    • 보존과학연구
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    • s.32
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    • pp.123-136
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    • 2011
  • There are more than 2,800 different species of termites in the world, but just there is one species (Reticulitermes speratus kyushuensis Morimoto) in Korea. Once wooden structures are damaged by termites, we are applying chemical control methods such as fumigation, treatment of insecticidal and antiseptic chemicals, soil termiticide treatment, and termite colony elimination system to pest control. But in Korea, the termite infestation is gradually increasing, so it is essential to study on the present situation of termite control in US or Japan. Accordingly, in this part we have studied focusing on the case of US. In the US, there are three groups of termites : Subterranean, Drywood, Dampwood termites, and they caused more severe infestation compared with Korea. When a structure has become infested with termites, it is important that appropriate action must be taken: the chemical pest control (soil treatment, termite baiting, termite colony elimination), the modification and maintenance of buildings and the regular inspection for follow-up. And with consideration for different characteristics of termites, the process of pest control is made according to each species of termites. Most of the subterranean termite control is done by applying either termiticide to the soil or termite monitoring and baiting system around the structure. On the other hand, drywood termite control methods can be categorized as either the treatment for the whole structure or the treatment for localized area. Applications to the whole structure are done by fumigants or heat and the localized treatments are carried out with chemicals as well as heat, freezing, microwave and electricity.

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Applicability Study on Reticulitermes speratus kyushuensis (Isoptera: Rhinotermitidae) Colony Eliminator to Preserve Wooden Cultural Heritage (일본흰개미 아종 모니터링 및 군체제거를 위한 예찰제어기 개발 연구)

  • Chung, Yong Jae;Kim, Si Hyun;Kim, Youn Ju;Yu, Jae Seung
    • Journal of the Korean Wood Science and Technology
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    • v.43 no.6
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    • pp.818-825
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    • 2015
  • This study is conducted to develop new termite colony elimination system that can control termite colony much faster, and to eco-environmentally prevent termite damage occurred in wooden cultural heritage. As a result of laboratory test, we developed a component system, of which fipronil 0.001% (w/w) treated bait was used as a suitable termite colony eliminator. This system can be monitored without taking off underground, and it makes regular monitoring much more efficient. The result of field test showed that 36 termite baiting devices among 367 installed devices were damaged by foraging termites. After baiting, all of termite colonies attracted to devices were eliminated or their activity clearly decreased.

EVALUATION OF ENTEROCOCCUS FAECALIS REMOVAL EFFICACY OF THE ENDOVAC® AND ENDOACTIVATOR® INTRACANAL IRRIGATION METHODS (EndoVac®과 EndoActivator®를 이용한 근관세척법의 Enterococcus faecalis 제거 효율 평가)

  • Song, Seung-Gon;Park, Se-Hee;Cho, Kyung-Mo;Kim, Jin-Woo
    • Restorative Dentistry and Endodontics
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    • v.34 no.5
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    • pp.390-396
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    • 2009
  • The aim of this study was to evaluate endodontic irrigation methods with $EndoVac^{(R)}$ and $EndoActivator^{(R)}$ in the elimination of Enterococcus faecalis from the root canals. Extracted 70 human single-rooted teeth were used. The canals were instrumented by a crown-down technique with .04 taper ProFile to ISO size 40. After the teeth were autoclaved, the canals were inoculated with E. faecalis and incubated for 48 h. The teeth were randomly divided into three experimental groups of 20 teeth each according to canal irrigation methods and two control groups as follows: group 1 - $EndoVac^{(R)}$; group 2 - $EndoActivator^{(R)}$; group 3-Conventional needle irrigation method. After canal irrigation using 2.5% NaOCl. first samples (S1) were taken using sterile paper point. And the canals were filled with sterile brain heart infusion (BHI) broth and incubated for 24 h, then second samples (S2) were taken. The samples were cultured on BHI agar plate to determine the numbers of colony forming units (CFU). In first sampling (S1), only one canal of conventional method among the all experimental groups was positive cultured. In second sampling (S2), $EndoVac^{(R)}$ group showed the least positive culture numbers of E. faecalis. There was statistically significant difference between the $EndoVac^{(R)}$ and conventional needle irrigation methods in the mean value of Log CFU. According to the results of this study, $EndoVac^{(R)}$ showed better efficacy than conventional needle irrigation method in the elimination of E. faecalis from the root canal.

In vitro evaluation of octenidine as an antimicrobial agent against Staphylococcus epidermidis in disinfecting the root canal system

  • Chum, Jia Da;Lim, Darryl Jun Zhi;Sheriff, Sultan Omer;Pulikkotil, Shaju Jacob;Suresh, Anand;Davamani, Fabian
    • Restorative Dentistry and Endodontics
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    • v.44 no.1
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    • pp.8.1-8.7
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    • 2019
  • Objectives: Irrigants are imperative in endodontic therapy for the elimination of pathogens from the infected root canal. The present study compared the antimicrobial efficacy of octenidine dihydrochloride (OCT) with chlorhexidine (CHX) and sodium hypochlorite (NaOCl) against Staphylococcus epidermidis (S. epidermidis) for root canal disinfection. Materials and Methods: The minimum inhibitory concentration (MIC) was obtained using serial dilution method. The agar diffusion method was then used to determine the zones of inhibition for each irrigant. Lastly, forty 6-mm dentin blocks were prepared from human mandibular premolars and inoculated with S. epidermidis. Samples were randomly divided into 4 groups of 10 blocks and irrigated for 3 minutes with saline (control), 2% CHX, 3% NaOCl, or 0.1% OCT. Dentin samples were then collected immediately for microbial analysis, including an analysis of colony-forming units (CFUs). Results: The MICs of each tested irrigant were 0.05% for CHX, 0.25% for NaOCl, and 0.0125% for OCT. All tested irrigants showed concentration-dependent increase in zones of inhibition, and 3% NaOCl showed the largest zone of inhibition amongst all tested irrigants (p < 0.05). There were no significant differences among the CFU measurements of 2% CHX, 3% NaOCl, and 0.1% OCT showing complete elimination of S. epidermidis in all samples. Conclusions: This study showed that OCT was comparable to or even more effective than CHX and NaOCl, demonstrating antimicrobial activity at low concentrations against S. epidermidis.

Prediction and analysis of optimal frequency of layered composite structure using higher-order FEM and soft computing techniques

  • Das, Arijit;Hirwani, Chetan K.;Panda, Subrata K.;Topal, Umut;Dede, Tayfun
    • Steel and Composite Structures
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    • v.29 no.6
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    • pp.749-758
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    • 2018
  • This article derived a hybrid coupling technique using the higher-order displacement polynomial and three soft computing techniques (teaching learning-based optimization, particle swarm optimization, and artificial bee colony) to predict the optimal stacking sequence of the layered structure and the corresponding frequency values. The higher-order displacement kinematics is adopted for the mathematical model derivation considering the necessary stress and stain continuity and the elimination of shear correction factor. A nine noded isoparametric Lagrangian element (eighty-one degrees of freedom at each node) is engaged for the discretisation and the desired model equation derived via the classical Hamilton's principle. Subsequently, three soft computing techniques are employed to predict the maximum natural frequency values corresponding to their optimum layer sequences via a suitable home-made computer code. The finite element convergence rate including the optimal solution stability is established through the iterative solutions. Further, the predicted optimal stacking sequence including the accuracy of the frequency values are verified with adequate comparison studies. Lastly, the derived hybrid models are explored further to by solving different numerical examples for the combined structural parameters (length to width ratio, length to thickness ratio and orthotropicity on frequency and layer-sequence) and the implicit behavior discuss in details.

Termite monitoring and control managements for wooden building (목조건조물의 흰개미 모니터링 및 방제방법)

  • Lee, Kyu-Shik;Jeong, So-Young;Chung, Yong-Jae
    • 보존과학연구
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    • s.22
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    • pp.41-52
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    • 2001
  • The wooden building is mainly damaged by the termite which have an effect of the structure by making emptied inner part of wood. One class, Japanese termite, inhabits throughout Korea and is often detected. So the deterioration by termite attacking the wooden building needs to be controlled. Termites are over 2,800 species in the world, usually they inhabit in the tropical or subtropical region and don’t over winter in dormant condition. So their activity and distribution are chiefly restricted by temperature and humidity. The termite inhabiting in Korea is Reticulitermes speratus kyushuensis Morimoto, which known to have an optimal temperature range at $12~30^{\circ}C$ and minimum temperature at $6^{\circ}C$ for activation. These temperatures correspond to the mean temperature($5.6^{\circ}C$~$25.8^{\circ}C$) from March to November and the activity time of termitein Seoul. In addition, as a result of environmental pollution by industrial development, the climate of Korea is getting warm. The increase of mean temperature in Korea has been $1.1^{\circ}C$ for the past seventy five years, so it is expected that the damage of wooden building by termite will increase gradually. Therefore, in order to protect wooden building from damages by termite, it needs not only development of new pest control methods, but also studies on the control of environmental factors having an effect on the activity and growth of termite. For the conservation of the large cultural properties such as the wooden building in the open air, it would be effective to use the methods of fumigation, insecticidal and antiseptic chemical treatment of wood materials, soil termiticideinjection treatment, and termite colony elimination system.

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