• Title, Summary, Keyword: Electrostatics

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Properties of Electrostatic Electrification Degradation due to Contaminant Difference of Silicone Rubbers (오손액 변화에 따른 실리콘 고무의 정전기 대전열화 특성)

  • Lee, Sung Ill
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.28 no.9
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    • pp.587-592
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    • 2015
  • In this study, the electrification voltage of electrostatics for silicone rubber sample($4cm{\times}4cm{\times}0.103cm$) following immersion with contaminants of 2 ml, 5 ml, 10 ml for six hours has been measured in through the applied voltage of 10 kV DC at temperature of $80^{\circ}C{\sim}110^{\circ}C$, humidity of 50%~90%. The results of this study are as follows. In case the contaminants is constant, it found that the electrification voltage of electrostatic decreased with increasing temperature and humidity to $35^{\circ}C$, 90%. In case of 2 ml of contaminants concentration, it found that the electrification voltage of electrostatic decreased with increasing temperature and humidity to $35^{\circ}C$, 50%. In case of the sample at temperature of $15^{\circ}C$ and humidity of 50%, it found that the electrification voltage of electrostatic decreased with increasing contaminants to 10 ml.

A hybrid CSS and PSO algorithm for optimal design of structures

  • Kaveh, A.;Talatahari, S.
    • Structural Engineering and Mechanics
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    • v.42 no.6
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    • pp.783-797
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    • 2012
  • A new hybrid meta-heuristic optimization algorithm is presented for design of structures. The algorithm is based on the concepts of the charged system search (CSS) and the particle swarm optimization (PSO) algorithms. The CSS is inspired by the Coulomb and Gauss's laws of electrostatics in physics, the governing laws of motion from the Newtonian mechanics, and the PSO is based on the swarm intelligence and utilizes the information of the best fitness historically achieved by the particles (local best) and by the best among all the particles (global best). In the new hybrid algorithm, each agent is affected by local and global best positions stored in the charged memory considering the governing laws of electrical physics. Three different types of structures are optimized as the numerical examples with the new algorithm. Comparison of the results of the hybrid algorithm with those of other meta-heuristic algorithms proves the robustness of the new algorithm.

Electret-based microgenerators under sinusoidal excitations: an analytical modeling

  • Nguyen, Cuong C.;Ranasinghe, Damith C.;Al-Sarawi, Said F.
    • Smart Structures and Systems
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    • v.21 no.3
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    • pp.335-347
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    • 2018
  • The fast-growing number of mobile and wearable applications has driven several innovations in small-scale electret-based energy harvesting due to the compatibility with standard microfabrication processes and the ability to generate electrical energy from ambient vibrations. However, the current modeling methods used to design these small scale transducers or microgenerators are applicable only for constant-speed rotations and small sinusoidal translations, while in practice, large amplitude sinusoidal vibrations can happen. Therefore, in this paper, we formulate an analytical model for electret-based microgenerators under general sinusoidal excitations. The proposed model is validated using finite element modeling combined with numerical simulation approaches presented in the literature. The new model demonstrates a good agreement in estimating both the output voltage and power of the microgenerator. This new model provides useful insights into the microgenerator operating mechanism and design trade-offs, and therefore, can be utilized in the design and performance optimization of these small structures.

APPLIED SYMMETRICAL PRINCIPLE TO SOLVE SCHWARZ-CHRISTOFFEL PARAMETER PROBLEM

  • YUAN, MEI;PENG, HUIQING;LEI, YUN
    • Proceedings of the Jangjeon Mathematical Society
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    • v.21 no.4
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    • pp.599-616
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    • 2018
  • This paper adopted symmetry theory to solve the Schwarz-Christoffel parameter problem for axisymmetric polygons. Numerical conformal mappings were performed to shift the upper half-plane onto polygonal domains. Once the constraint conditions of the problem were treated in a special way such as added or deleted a little area, it turns to be a solution of a singular integral.In this paper, an auxiliary point was suggested to attach to the polygon that obeyed the principle of symmetry, which can accelerate the solving process of the singular integral. After that, several numerical examples, along with an application related to electrostatics, are provided to verify its feasibility and simplification. When the distance from the auxiliary point to polygon is controlled under 1E-08, the accuracy can be controlled within 1E-09, accuracy and consequences of the calculation basically meet the ordinary requirement.

Ligand Based CoMFA, CoMSIA and HQSAR Analysis of CCR5 Antagonists

  • Gadhe, Changdev G.;Lee, Sung-Haeng;Madhavan, Thirumurthy;Kothandan, Gugan;Choi, Du-Bok;Cho, Seung-Joo
    • Bulletin of the Korean Chemical Society
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    • v.31 no.10
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    • pp.2761-2770
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    • 2010
  • In this study, we have developed QSAR models for a series of 38 piperidine-4-carboxamide CCR5 antagonists using CoMFA, CoMSIA and HQSAR methods. Developed models showed good statistics in terms of $q^2$ and $r^2$ values. Best predictions obtained with standard CoMFA model ($r^2$ = 0.888, $q^2$ = 0.651) and combined CoMSIA model ($r^2$ = 0.892, $q^2$ = 0.665) with electrostatics and H-bond acceptor parameter. The validity of developed models was assessed by test set of 9 compounds, which showed good predictive correlation coefficient for CoMFA (0.804) and CoMSIA (0.844). Bootstrapped analysis showed statistically significant and robust CoMFA (0.968) and CoMSIA (0.936) models. Best HQSAR model was obtained with a $q^2$ of 0.662 and $r^2$ of 0.936 using atom, connection, hydrogen, donor and acceptor as parameters and fragment size (7-10) with optimum number of 6 components. Predictive power of developed HQSAR model was proved by test set and it was found to be 0.728.

Thermoelectric Seebeck and Peltier effects of single walled carbon nanotube quantum dot nanodevice

  • El-Demsisy, H.A.;Asham, M.D.;Louis, D.S.;Phillips, A.H.
    • Carbon letters
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    • v.21
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    • pp.8-15
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    • 2017
  • The thermoelectric Seebeck and Peltier effects of a single walled carbon nanotube (SWCNT) quantum dot nanodevice are investigated, taking into consideration a certain value of applied tensile strain and induced ac-field with frequency in the terahertz (THz) range. This device is modeled as a SWCNT quantum dot connected to metallic leads. These two metallic leads operate as a source and a drain. In this three-terminal device, the conducting substance is the gate electrode. Another metallic gate is used to govern the electrostatics and the switching of the carbon nanotube channel. The substances at the carbon nanotube quantum dot/metal contact are controlled by the back gate. Results show that both the Seebeck and Peltier coefficients have random oscillation as a function of gate voltage in the Coulomb blockade regime for all types of SWCNT quantum dots. Also, the values of both the Seebeck and Peltier coefficients are enhanced, mainly due to the induced tensile strain. Results show that the three types of SWCNT quantum dot are good thermoelectric nanodevices for energy harvesting (Seebeck effect) and good coolers for nanoelectronic devices (Peltier effect).

A Study for Development and Characteristics of Electrostatic Eliminator Suitable for the Super Clean Room Less than Class 100(I) (공기 청정지역(Class 100 이하)에 적합한 정전기 제거장치의 개발 및 특성에 관한 연구(I) - LCD 제조 공정을 중심으로 -)

  • Jung, Yong-Chul;Park, Hoon-Kyu;Lee, Dong-Hoon
    • Journal of the Korean Society of Safety
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    • v.21 no.4
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    • pp.60-65
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    • 2006
  • It is a well known fact that LCD is a central part of the IT industry which is important in the present and the future. But the biggest problem of LCD manufacturing is maintaining a cleaning room environment and administration. Therefore the purpose of this study is to first, prevent the yield depreciation and damage of products, and second, protect the worker ftom accidental electrostatic discharge during LCD manufacture. The soft x-ray ionizer is a type of electrostatic reducer device. It protects against electrostatic discharge in the cleaning room environment and is a necessary environmental factor during LCD production. The positive aspects of the soft x-ray are its shorter time and wider angle of exposure. But the negative aspect of the soft x-ray is its need for several shielding of protection from the harmful x-ray exposure. On this study, the development of the Air Nozzle-type ionizer to amend and refine some problems. For example, examined the electrostatic reduce device of a soft x-ray type and discovered the ion did not go inside well. also workers to be free from danger. An Air Nozzle-type ionizer is comprised of soft x-ray radiation and ionized air production. Air is injected through the nozzle after being ionized from radiation. It supplies air keeping the same pressure into the end foundation of ion production. The soft x-ray is the structure which radiates ionized air through the nozzle (21 holes) having micro holes of the ionizable radiation after ionizing the inside air by the ion production. A worker does not need a cover to protect against x-rays and the Air Nozzle-type ionizer is easy to set up and is more effective at eliminating electrostatic.

Studies on the Chromatin Isolated from the Organs of Animals Received Whole-body X-ray Irradiation (백서장기(白鼠臟器)에서의 Chromatin의 분리(分離)와 그 RNA 합성능(合成能)에 미치는 X-선전신조사(線全身照射)의 영향(影響)에 관(關)한 연구(硏究))

  • Han, Su-Nam
    • The Korean Journal of Nuclear Medicine
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    • v.1 no.2
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    • pp.27-34
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    • 1967
  • 1. Within experimental chromatin, the total protein: DNA ratio did not vary in the same organs of control and irradiated rats. However, the amount of RNA and total protein associated with the DNA varied considerably among the different types of chromatin. In particular, the content of chromatin was the highest in the irradiated tissue, and the lowest in the chromatin control tissue. RNA and total protein ratio of chromatins from brain, liver, testis and spleen declined with experimental organs. 2. There was the same quantitative relationship between the amount of RNA and the amount histone-protein associated with DNA in each chromatin. 3. RNA:DNA ratio of chromatin showed a $1.5{\sim}2$ times increase in the irradiated organs except brain. However, RNA:DNA ratio was decreased in chromatin by irradiation. 4. Histone-protein:Residual protein ratio was greatly varied among the organs. However, the effect was not found by irradiation. 5. Priming activity of chromatins showed a higher value in testis and the activity was greater in organs with higher metabolic activity. 6. Inhibition of Actinomycin D observable in chromatin for testis, liver, spleen and brain declined without relationship between irradiated and non-irradiated conditions. Ammonium sulfate in DNA of chromatin from histone showed increased priming activity with dissociation by Electrostatics. It may give different effect of ammonium sulfate on stimulation by property of chromatins. 7. It is suggested that the results support a proposal that the higher sensitivity of radioactive in testis, spleen by irradiated showed a increase and decrease lower-sensitivity of radioactive from brain, liver than did priming activity under the radioactive conditions.

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A Study on Hazards Assessment of Electrostatic Firing Explosion of Working Wears at LPG Stations in Korea (한국의 LPG 충전소에 있어서 작업복의 정전기에 의한 화재 및 폭발 위험성에 관한 연구)

  • Cho young doo;Koo Ja Hyeuk;Choi Kwang Seo;Seo Dae Won;Joung Jae Hee;Takeuchi Manabu
    • Journal of the Korean Institute of Gas
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    • v.4 no.4
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    • pp.20-24
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    • 2000
  • The electrostatic safety consciousness of safety manager were investigated through questionnaires sent to liquid petroleum gas stations in Korea. In addition, hazards of fire and explosion due to electrostatic on synthetic-polymer-wears and cotton-wears were estimated experimentally. The results of questionnaires indicate most workers wear their working clothes indiscreetly owing to lack of knowledge of preventing electrostatic hazards. The amounts of electrostatic charge generated in synthetic-polymer-wears were 1.79, 1.44 and 1.02 $\mu$C in winter, spring and autumn and summer, respectively. All these values exceed the limit of working wears of 0.60$\mu$C requested by Korea Standard(KS K-7807) for preventing electrostatic hazards, which means hazards may occur. While, the charge in cotton-wears were in the range of 0.42 to 0.52$\mu$C, which suggests that the cotton-wears investigated in this study have no problem of hazards. Therefore workers, visual and experiential education are necessary for elevating the standard of on electrostatics. It is also necessary to establish standards of wearing for preventing electrostatic hazards.

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