The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform
Kuo Hsiung Tseng - One of the best experts on this subject based on the ideXlab platform.
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Preparation of Graphene Colloids in Different Dispersing Devices by Electric Spark Discharge Method and Analysis of Their Suspension Stability
2019 IEEE 6th International Conference on Industrial Engineering and Applications (ICIEA), 2019Co-Authors: Kuo Hsiung Tseng, Hsueh-chien Ku, Chaur-yang ChangAbstract:In this study, Electrical discharge machine (EDM) was used to prepare graphene colloids by the Electric Spark discharge method (ESDM). Machine-lathed 99% pure graphite rods were used as the electrodes, deionized water (DI water) was used as the diElectric liquor, and a magnetic stirrer and ultrasonic cleaner were used as the dispersing devices. According to the analysis results from ultraviolet-visible spectroscopy (UV-Vis), Zetasizer, and transmission electron microscope (TEM), the characteristic wavelength of graphene was 260 nm with an absorbance of 0.219 and a zeta potential of -36.6 mV, and many graphene laminates could be seen based on the microscale. This study discussed the two different dispersing devices used to make graphene colloids and analyzed their impact on suspension stability. The results showed that a magnetic stirrer was suitable for making graphene colloids with high suspension stability and low concentration, while an ultrasonic cleaner was suitable for making graphene colloids with low suspension stability and high concentration. The graphemes made by the chemical method are difficult to suspend in water and chemical or dispersant additives are required to maintain their properties; furthermore, which increases the production time. However, with no need for chemical additions and a short preparation time, ESDM is a safe, environmentally-friendly, and fast green manufacturing method.
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Analysis of the suspension stability of silver nanocolloids prepared by Electric Spark discharge method
2018 13th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2018Co-Authors: Kuo Hsiung Tseng, Chaur-yang Chang, Meng-yun ChungAbstract:This study uses the Electric Spark discharge method (ESDM) to prepare silver nanocolloids (SNC). The devices and material for the preparation include an industrial Electric discharge machine (EDM), magnetic stirrer, ultrasonic oscillator, 99.9% pure silver wires, and deionized water (DW). According to the analysis of the field-emission scanning electron microscopy (FE-SEM), UV-Vis and Zetasizer, the prepared SNC has nanoparticles (NPs), the wavelength eigenvalue is 393nm, absorbent concentration is 0.22, and zeta-potential is -38.9mV. The results demonstrate that ESDM can prepare SNC with good suspension stability. In this experiment, which discusses the effect of a magnetic stirrer and an ultrasonic oscillator on the suspension stability of SNC, the analysis of the absorbent concentration of the UV-Vis showed that the agglomerated NPs can be dispersed by using a magnetic stirrer or ultrasonic oscillator. According to the analysis of Zetasizer, the colloids that are remixed by a magnetic stirrer or ultrasonic oscillator contain a large number of NPs. As compared to other SNC preparation methods, ESDM can provide a clean process environment without dust emissions, and no suspending agents are added in the process. As the prepared colloids contain no other derivatives, it can be applied to antibacterial deodoriz ation. If it is used for water purification, secondary pollution can be prevented. If used in cosmetics, personal protective products, and medical purposes, it can avoid adverse effects on the human body.
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Silver carbonate and stability in colloidal silver: A by-product of the Electric Spark discharge method
Journal of Alloys and Compounds, 2010Co-Authors: Kuo Hsiung Tseng, Chih-yu Liao, D. C. TienAbstract:Abstract Many methods of producing colloidal silver (CS) include the introduction of surfactants to improve the suspensivity of the silver particles. The Electric Spark discharge method (ESDM) which involves pulses of direct current being passed through a silver electrode submerged in deionized water has been shown to successfully produce colloidal silver in a stable suspension without the use of chemical additives. A by-product of the Electric Spark discharge method, a silver ion compound (AgX), is shown to be the cause of the high suspensivity of the silver nanoparticles (AgNPs). The silver ion compound has been identified as Ag 2 CO 3 using X-ray diffraction, and it has been determined that the Ag 2 CO 3 is formed during the Electric Spark discharge process through a reaction with atmospheric CO 2 . It has been shown that an Ag 2 CO 3 concentration of 10 ppm or more is sufficient to generate a stable suspension of silver particles. Because of the occurrence of Ag 2 CO 3 , the Electric Spark discharge method can produce stable colloidal silver.
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identification and quantification of ionic silver from colloidal silver prepared by Electric Spark discharge system and its antimicrobial potency study
Journal of Alloys and Compounds, 2009Co-Authors: D. C. Tien, Chih-yu Liao, Kuo Hsiung Tseng, Tsing-tshih TsungAbstract:Abstract The study of nanoparticles has become a target of major interest in science. Metallic silver nanoparticles (Ag0) and ionic silver (Ag+) are the future of the post-antibiotic era, with the latter playing perhaps the central role in this fight. Traditional chemical synthesis methods for colloidal silver (CS) may lead to the presence of toxic chemical species or chemical residues, which may inhibit the effective authentication of CS as an antibacterial agent. To counter these problems a good alternative method—Electric Spark discharge system (ESDS) was used to fabricate a silver nanoparticles suspension in deionized water with no added chemical additives. Most related research in this field is confined to exploring the composition of nanoparticle, ignoring ions. However, we aim to identify and quantify the proportion of ionic silver in ESDS-CS. The results reveal that ESDS-CS contains both metallic silver nanoparticles and ionic silver. Furthermore, the antimicrobial affect of ESDS-CS on Staphylococcus aureus was also studied. The experimental data suggest that CS solutions with an ionic silver concentration of 30 ppm or higher are strong enough to eliminate S. aureus. In addition, it was found that a solution's antimicrobial potency is directly related to its level of silver ion concentration.
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Identification and quantification of ionic silver from colloidal silver prepared by Electric Spark discharge system and its antimicrobial potency study
Journal of Alloys and Compounds, 2009Co-Authors: D. C. Tien, Chih-yu Liao, Kuo Hsiung Tseng, Tsing-tshih TsungAbstract:The study of nanoparticles has become a target of major interest in science. Metallic silver nanoparticles (Ag0) and ionic silver (Ag+) are the future of the post-antibiotic era, with the latter playing perhaps the central role in this fight. Traditional chemical synthesis methods for colloidal silver (CS) may lead to the presence of toxic chemical species or chemical residues, which may inhibit the effective authentication of CS as an antibacterial agent. To counter these problems a good alternative method-Electric Spark discharge system (ESDS) was used to fabricate a silver nanoparticles suspension in deionized water with no added chemical additives. Most related research in this field is confined to exploring the composition of nanoparticle, ignoring ions. However, we aim to identify and quantify the proportion of ionic silver in ESDS-CS. The results reveal that ESDS-CS contains both metallic silver nanoparticles and ionic silver. Furthermore, the antimicrobial affect of ESDS-CS on Staphylococcus aureus was also studied. The experimental data suggest that CS solutions with an ionic silver concentration of 30 ppm or higher are strong enough to eliminate S. aureus. In addition, it was found that a solution's antimicrobial potency is directly related to its level of silver ion concentration. © 2008 Elsevier B.V. All rights reserved.
M. H. Keshavarz - One of the best experts on this subject based on the ideXlab platform.
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Correlation between shock sensitivity of nitramine energetic compounds based on small-scale gap test and their Electric Spark sensitivity
Zeitschrift für anorganische und allgemeine Chemie, 2017Co-Authors: M. H. Keshavarz, Mohammad Ghaffarzadeh, Mohammadreza Omidkhah, Kiumars FarhadiAbstract:Electric Spark sensitivity and shock sensitivity based small-scale gap test for nitramine energetic compounds are two important sensitivity parameters, which are needed for assessment of their safety in working places. A novel method is introduced for reliable prediction of Electric Spark or shock sensitivity of a desired nitramine energetic compound when reliable data for one of the sensitivity is available. A novel correlation with a high value of correlation coefficient (R2=0.998) is derived between Electric Spark and shock sensitivities of 20 cyclic and acyclic nitramines. For these nitramines, the predicted results of Electric Spark sensitivities of the novel model are compared with two of the best available models. The root-mean-square (rms) and maximum deviations of the new model are 0.20 and 0.51 J, respectively, which are much less than two comparative methods. The reliability of the new method for prediction of Electric Spark sensitivity of further 14 nitramines is also compared with one of the best available methods, where the measured Electric Spark or shock sensitivities were not available in literature.
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Relation between Electric Spark Sensitivity and Impact Sensitivity of Nitroaromatic Energetic Compounds
Zeitschrift für anorganische und allgemeine Chemie, 2016Co-Authors: M. H. Keshavarz, Zahra KeshavarzAbstract:Impact and Electric Spark sensitivities of energetic compounds are two important sensitivity parameters, which are closely related to many accidents in working places. In contrast to Electric Spark sensitivity, impact sensitivity can be easily measured. A new simple method is introduced to correlate Electric Spark and impact sensitivities of nitroaromatic compounds. Two correcting functions are used to consider several molecular moieties for reliable prediction of Electric Spark sensitivity through the measured or estimated impact sensitivity of nitroaromatics. The model is optimized using a set of 28 CHNO polynitroaromatic explosives and then it is tested for some nitroaromatics containing the other atoms such as sulfur. The predicted Electric sensitivities of the new method are also compared with the reported results of a new quantum mechanical approach. For 22 CHNO nitroaromatics, quantum mechanical calculations are within ±3.0 J of 18 measured values and more than ±3.0 J for remaining 4 experimental data. Meanwhile, the predicted results of the method are less than ±3.0 J for 28 CHNO nitroaromatics. The root-mean-square (rms) deviations of the new model and quantum mechanical are also 1.55 and 2.51 J, respectively.
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Relationship between Electric Spark sensitivity and activation energy of the thermal decomposition of nitramines for safety measures in industrial processes
Journal of Loss Prevention in The Process Industries, 2013Co-Authors: M. H. Keshavarz, Narges Zohari, Seyed Abolfazl SeyedsadjadiAbstract:Abstract This study presents a new simple correlation between Electric Spark sensitivity of nitramines and their activation energies of thermolysis, which are important for safety measures in industrial processes. The new correlation can help to elucidate the mechanism of initiation of energetic materials by Electric Spark. It can be used to predict the magnitude of Electric Spark sensitivity of new nitramines, which is difficult to measure. The methodology assumes that Electric Spark sensitivity of a nitramine with general formula C a H b N c O d can be expressed as a function of its activation energy of thermal decomposition as well as optimized elemental composition and the contribution of specific molecular structural parameters. The new correlation has the root mean square and the average deviations of 1.37 and 1.09 J, respectively, for 21 nitramines with different molecular structures. The proposed new method is also tested for 16 nitramines so that there is no experimental data of electrostatic sensitivity for them.
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Reliable prediction of Electric Spark sensitivity of nitramines: a general correlation with detonation pressure.
Journal of hazardous materials, 2009Co-Authors: M. H. Keshavarz, Hamid Reza Pouretedal, Abolfazl SemnaniAbstract:For nitramines, a general correlation has been introduced to predict Electric Spark sensitivity through detonation pressure. New method uses maximum obtainable detonation pressure as a fundamental relation so that it can be corrected for some nitramines which have some specific molecular structure. There is no need to use crystal density and heat of formation of nitramine explosives for predicting detonation pressure and Electric Spark sensitivity. The predicted Electric Spark sensitivities are compared with calculated results on the basis of quantum mechanical computations for some nitramines that latter can be applied. The root mean square (rms) deviations from experiment for new method and the predicted results of complicated quantum mechanical method are 1.18 and 3.49J, respectively.
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A simple way to predict Electric Spark sensitivity of nitramines
Indian Journal of Engineering and Materials Sciences, 2008Co-Authors: M. H. Keshavarz, Hamid Reza Pouretedal, Abolfazl SemnaniAbstract:This work presents a new simple method for predicting Electric Spark sensitivity of nitramine energetic compounds. This method is based on the calculated detonation velocity at maximum nominal density (theoretical maximum density) and then corrected for some nitramines which have some specific molecular structure. The predicted Electric Spark sensitivity by new method are compared with calculated results on the basis of quantum mechanical computations for 17 nitramines so that the root mean square (rms) deviations from experiment for new and complicated quantum mechanical methods are 1.23 and 4.02 J, respectively. The new model is also used for two new nitamine explosives TNAZ [1,3,3-trinitroazatidine] and TEX [4,10-dinitro-2,6,8,10-tetraoxa-4,10-diazaisowurtzitane] in which predicted results are close to measured values.
Irina A. Podchernyaeva - One of the best experts on this subject based on the ideXlab platform.
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Formation of Fine-Dispersion Structures by Electric-Spark, Laser and Magnetron Coating With Ain-TiB 2 /ZrB 2 Composite Materials
Functional Gradient Materials and Surface Layers Prepared by Fine Particles Technology, 2020Co-Authors: Alla D. Panasyuk, Irina A. Podchernyaeva, R. A. Andrievsky, M. A. Teplenko, G. V. Kalinnikov, L. P. IsaevaAbstract:Structure, composition, tribological and corrosion properties of Electric-Spark, laser and magnetron coatings using advanced high-temperature AlN-TiB2/ZrB2 ceramics were studied. The similarity between the structures of Electric-Spark and laser coatings, showing the formation of globules after sintering of the finely dispersed composite material on a treated surface, was ascertained. The Al2iO5, ZrSiO4 and s-Al2TiO5 compounds, appearing in the coating directly during its formation, play a positive role in terms of tribological behavior for solid lubricants and of corrosion resistance as well. Under optimum conditions of Electric-Spark alloying of titanium VT6 and low-carbon 45 steel both friction coefficient and wear were decreased to 0.13-0.15 and 6-13 μm/km, respectively. The working temperature of the coated VT6 alloy was increased by 130 °C. The AIN-TiB2 magnetron coating on monocrystalline silicon is characterised by a continuous structure of the ultra-dispersion even under corrosion at a temperature as high as 1400 °C.
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Effect of Layer-by-Layer Electric-Spark Alloying on the Properties of an Electrolytic Coating of the System Ni – B
Powder Metallurgy and Metal Ceramics, 2020Co-Authors: Irina A. Podchernyaeva, Alexei D. Kostenko, Yurii A. Guslienko, I. V. UvarovaAbstract:The effect of layer-by-layer Electric-Spark alloying on the tribological parameters of a composite electrolytic coating of the system Ni – B is studied. It is shown that layer-by-layer Electric-Spark alloying with intermetallic TiAl and a composite AlN – ZrB2 halves coating wear and prevents transfer of coating material to the counterbody. The reason for this is formation of a graded structure for the surface layer including zircon ZrSiO4 and intermetallic TiAl. The latter is responsible for formation of β-tialite during tribological oxidation acting as a solid lubricant.
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Surface Modification of AL9 Alloy by Electric-Spark Alloying with Materials of the AlN – Ti(Zr)B_2 – Ti(Zr)Si_2System
Powder Metallurgy and Metal Ceramics, 2004Co-Authors: Irina A. Podchernyaeva, Alla D. Panasyuk, Dmitrii V. YurechkoAbstract:Using x-ray phase, electron-probe microanalysis, and scanning electron microscopy, we have established that heterophase coatings based on an aluminum matrix with a quasi-layered finely dispersed structure reinforced with titanium (zirconium) diboride and borosilicide, and aluminum nitride (alloyed with oxygen) are formed by Electric-Spark alloying of AL9 alloy with A1N – Ti(Zr)B_2 – Ti(Zr)Si_2 composite ceramics. The wear resistance of the A1N – ZrB2-based coating approached that of the ceramic itself with the sliding speed increased to V ≥ l m/sec. The formation of secondary structures of oxide solid solutions on the coating surface during tribooxidation was investigated.
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Physicochemical properties of Electric-Spark coatings based on VT6 titanium alloy
Materials Science, 1996Co-Authors: Irina A. Podchernyaeva, Vladimir A. Lavrenko, V. I. Berezanskaya, V. A. ShvetsAbstract:We establish regularities of the process of formation and physicomechanical and physicochemical properties of the surface of VT6 titanium alloy subjected to Electric-Spark alloying with electrode materials based on refractory compounds of titanium and zirconium. It is shown that, in the process of ElectricSpark alloying, the maximum hardness and electrochemical resistance of the alloyed layer in natural corrosive environments are attained for materials based on carbide and titanium carbonitride and the highest resistance to high-temperature oxidation is attained for materials based on zirconium nitride and titanium carbonitride.
Meng-yun Chung - One of the best experts on this subject based on the ideXlab platform.
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Analysis of the suspension stability of silver nanocolloids prepared by Electric Spark discharge method
2018 13th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2018Co-Authors: Kuo Hsiung Tseng, Chaur-yang Chang, Meng-yun ChungAbstract:This study uses the Electric Spark discharge method (ESDM) to prepare silver nanocolloids (SNC). The devices and material for the preparation include an industrial Electric discharge machine (EDM), magnetic stirrer, ultrasonic oscillator, 99.9% pure silver wires, and deionized water (DW). According to the analysis of the field-emission scanning electron microscopy (FE-SEM), UV-Vis and Zetasizer, the prepared SNC has nanoparticles (NPs), the wavelength eigenvalue is 393nm, absorbent concentration is 0.22, and zeta-potential is -38.9mV. The results demonstrate that ESDM can prepare SNC with good suspension stability. In this experiment, which discusses the effect of a magnetic stirrer and an ultrasonic oscillator on the suspension stability of SNC, the analysis of the absorbent concentration of the UV-Vis showed that the agglomerated NPs can be dispersed by using a magnetic stirrer or ultrasonic oscillator. According to the analysis of Zetasizer, the colloids that are remixed by a magnetic stirrer or ultrasonic oscillator contain a large number of NPs. As compared to other SNC preparation methods, ESDM can provide a clean process environment without dust emissions, and no suspending agents are added in the process. As the prepared colloids contain no other derivatives, it can be applied to antibacterial deodoriz ation. If it is used for water purification, secondary pollution can be prevented. If used in cosmetics, personal protective products, and medical purposes, it can avoid adverse effects on the human body.
Yunming Zhang - One of the best experts on this subject based on the ideXlab platform.
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shock wave generated by high energy Electric Spark discharge
Journal of Applied Physics, 2014Co-Authors: Yunming ZhangAbstract:Shock wave generated by Electric Spark discharge was studied experimentally and the shock wave energy was evaluated in this paper. A pressure measurement system was established to study the pressure field of the Electric Spark discharge process. A series of Electric Spark discharge experiments were carried out and the energy of the Electric Spark used in present study was in the range of 10 J, 100 J, and 1000 J, respectively. The shock wave energy released from the Electric Spark discharge process was calculated by using the overpressure values at different measurement points near the Electric Spark discharge center. The good consistency of shock wave energies calculated by pressure histories at different measuring points in the same Electric Spark discharge experiment illustrates the applicability of the weak shock wave theory in calculating the energy of shock wave induced by Electric Spark discharge process. The result showed that shock wave formed at the initial stage of Electric Spark discharge proce...