Electrokinetics in porous media

NARCIS (Netherlands)

Luong, D.T.

2014-01-01

This thesis presents the PhD research on electrokinetics in porous media. Electrokinetic phenomena are induced by the relative motion between a fluid and a solid surface and are directly related to the existence of an electric double layer between the fluid and the solid grain surface.

Numerical Simulations of Electrokinetic Processes Comparing the Use of a Constant Voltage Difference or a Constant Current as Driving Force

DEFF Research Database (Denmark)

Paz-Garcia, Juan Manuel; Johannesson, Björn; Ottosen, Lisbeth M.

Electrokinetic techniques are characterized by the use of a DC current for the removal of contaminants from porous materials. The method can be applied for several purposes, such as the recuperation of soil contaminated by heavy metals or organic compounds, the desalination of construction...... materials and the prevention of the reinforced concrete corrosion. The electrical energy applied in an electrokinetic process produces electrochemical reactions at the electrodes. Different electrode processes can occur. When considering inert electrodes in aqueous solutions, the reduction of water...... at the cathode is usually the dominant in the process. On the other hand, the electrode processes at the anode depend on the ions present in its vicinity. Oxidation of water and chloride are typically assumed to be the most common processes taking place. Electrons produced in the electrode processes...

Electrokinetic acceleration of DNA hybridization in microsystems.

Science.gov (United States)

Lei, Kin Fong; Wang, Yun-Hsiang; Chen, Huai-Yi; Sun, Jia-Hong; Cheng, Ji-Yen

2015-06-01

In this work, electrokinetic acceleration of DNA hybridization was investigated by different combinations of frequencies and amplitudes of actuating electric signals. Because the frequencies from low to high can induce different kinds of electrokinetic forces, i.e., electroosmotic to electrothermal forces, this work provides an in-depth investigation of electrokinetic enhanced hybridization. Concentric circular Cr/Au microelectrodes of 350 µm in diameter were fabricated on a glass substrate and probe DNA was immobilized on the electrode surface. Target DNA labeled with fluorescent dyes suspending in solution was then applied to the electrode. Different electrokinetic forces were induced by the application of different electric signals to the circular microelectrodes. Local microfluidic vortexes were generated to increase the collision efficiency between the target DNA suspending in solution and probe DNA immobilized on the electrode surface. DNA hybridization on the electrode surface could be accelerated by the electrokinetic forces. The level of hybridization was represented by the fluorescent signal intensity ratio. Results revealed that such 5-min dynamic hybridization increased 4.5 fold of signal intensity ratio as compared to a 1-h static hybridization. Moreover, dynamic hybridization was found to have better differentiation ability between specific and non-specific target DNA. This study provides a strategy to accelerate DNA hybridization in microsystems. Copyright © 2015 Elsevier B.V. All rights reserved.

Potential Electrokinetic Remediation Technologies of Laboratory Scale into Field Application- Methodology Overview

Science.gov (United States)

Ayuni Suied, Anis; Tajudin, Saiful Azhar Ahmad; Nizam Zakaria, Muhammad; Madun, Aziman

2018-04-01

Heavy metal in soil possesses high contribution towards soil contamination which causes to unbalance ecosystem. There are many ways and procedures to make the electrokinetic remediation (EKR) method to be efficient, effective, and potential as a low cost soil treatment. Electrode compartment for electrolyte is expected to treat the contaminated soil through electromigration and enhance metal ions movement. The electrokinetic is applicable for many approaches such as electrokinetic remediation (EKR), electrokinetic stabilization (EKS), electrokinetic bioremediation and many more. This paper presents a critical review on comparison of laboratory scale between EKR, EKS and EK bioremediation treatment by removing the heavy metal contaminants. It is expected to propose one framework of contaminated soil mapping. Electrical Resistivity Method (ERM) is one of famous indirect geophysical tools for surface mapping and subsurface profiling. Hence, ERM is used to mapping the migration of heavy metal ions by electrokinetic.

Application to electrokinetic data to test the adsorption models

International Nuclear Information System (INIS)

Kosmulski, M.; Eriksson, P.; Gustafsson, J.; Rosenholm, J.B.

2000-01-01

The effect of adsorption of Gd(III) on the electrokinetic potential of silica (Aerosil, 390 m 2 /g) was studied at various Gd(III) concentrations (ranging from 10 -6 to 10 -2 mol dm -3 ) and at four different solid to liquid ratios (ranging from 0.05 to 8% of silica by weight). Up to some critical concentration of trivalent cations, their effect on the electrokinetic potential of silica is negligible and the sign is negative over the entire studied pH range. This critical concentration increases when the solid to liquid ratio increases. When Gd(III) concentration exceeds the critical value, the magnitude of the negative electrokinetic potential of silica is reduced. This effect is substantial at pH 6 but it is rather insignificant when the pH is very high (pH > 8) or very low (pH < 4). When the Gd(III) concentration is even higher, the sign of the electrokinetic potential is reversed to positive over certain pH range, which depends on the solid to liquid ratio and Gd(III) concentration. The shape of experimental electrokinetic curves of silica in the presence of trivalent cations often shows maximums and double isoelectric points, thus, it is very complex in comparison with the shape of the percentage of uptake vs. pH curves. Therefore, a test of an adsorption model based on electrokinetic curves is much more demanding than a test based merely on uptake vs. pH curves. The parameters of surface complexation model (SCM) derived from analysis of a large set of uptake curves were used to predict the course of electrokinetic curves. The calculated and experimentally observed maximums and isoelectric points do not exactly match (a difference up to one pH unit), but the model curves qualitatively reflect the trends observed in electrokinetic experiments. (orig.)

Selectivity in microemulsion electrokinetic chromatography

DEFF Research Database (Denmark)

Pedersen-Bjergaard, S; Gabel-Jensen, Charlotte; Honoré Hansen, S

2000-01-01

Microemulsion electrokinetic chromatography (MEEKC) is a most promising separation technique providing good selectivity and high separation efficiency of anionic, cationic as well as neutral solutes. In MEEKC lipophilic organic solvents dispersed as tiny droplets in an aqueous buffer by the use...

Comparative study of remediation of Cr(VI)-contaminated soil using electrokinetics combined with bioremediation.

Science.gov (United States)

He, Jiaying; He, Chiquan; Chen, Xueping; Liang, Xia; Huang, Tongli; Yang, Xuecheng; Shang, Hai

2018-06-01

The purpose of this research is to design a new bioremediation-electrokinetic (Bio-EK) remediation process to increase treatment efficiency of chromium contamination in soil. Upon residual chromium analysis, it is shown that traditional electrokinetic-PRB system (control) does not have high efficiency (80.26%) to remove Cr(VI). Bio-electrokinetics of exogenous add with reduction bacteria Microbacterium sp. Y2 and electrokinetics can enhance treatment efficiency Cr(VI) to 90.67% after 8 days' remediation. To optimize the overall performance, integrated bio-electrokinetics were designed by synergy with 200 g humic substances (HS) into the systems. According to our results, Cr(VI) (98.33%) was effectively removed via electrokinetics. Moreover, bacteria and humic substances are natural, sustainable, and economical enhancement agents. The research results indicated that the use of integrated bio-electrokinetics is an effective method to remediate chromium-contaminated soils.

A device for reduction of metal oxides generated in electrokinetic separation equipment

International Nuclear Information System (INIS)

Kim, Gye-Nam; Kim, Seung-Soo; Kim, Il-Gook; Jeong, Jung-Whan; Choi, Jong-Won

2015-01-01

For a reduction of waste electrolyte volume and metal oxide volume, the reuse period of the waste electrolyte in the electrokinetic decontamination experiment and the method of a reduction of metal oxide volume in the cathode chamber were drawn out through several experiments with the manufactured 1.2 ton electrokinetic decontamination equipment. The optimum pH of electrolyte in cathode chamber for a reduction of volume of metal oxides was below 2.35. Indoor electrokinetic decontamination equipment for treatment of 1.2 tons of the contaminated soil per batch was manufactured to remove uranium from soil with high removal efficiency during a short time. For a reduction of waste electrolyte volume and metal oxide volume, the reuse period of waste electrolyte in the electrokinetic decontamination experiment and the method of a reduction of metal oxide volume in the cathode chamber were drawn out through several experiments with the manufactured electrokinetic equipment. Indoor electrokinetic decontamination equipment for treatment of 1.2 tons of the contaminated soil was manufactured to remove uranium from soil during a short time

A device for reduction of metal oxides generated in electrokinetic separation equipment

Energy Technology Data Exchange (ETDEWEB)

Kim, Gye-Nam; Kim, Seung-Soo; Kim, Il-Gook; Jeong, Jung-Whan; Choi, Jong-Won [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-10-15

For a reduction of waste electrolyte volume and metal oxide volume, the reuse period of the waste electrolyte in the electrokinetic decontamination experiment and the method of a reduction of metal oxide volume in the cathode chamber were drawn out through several experiments with the manufactured 1.2 ton electrokinetic decontamination equipment. The optimum pH of electrolyte in cathode chamber for a reduction of volume of metal oxides was below 2.35. Indoor electrokinetic decontamination equipment for treatment of 1.2 tons of the contaminated soil per batch was manufactured to remove uranium from soil with high removal efficiency during a short time. For a reduction of waste electrolyte volume and metal oxide volume, the reuse period of waste electrolyte in the electrokinetic decontamination experiment and the method of a reduction of metal oxide volume in the cathode chamber were drawn out through several experiments with the manufactured electrokinetic equipment. Indoor electrokinetic decontamination equipment for treatment of 1.2 tons of the contaminated soil was manufactured to remove uranium from soil during a short time.

Washing-electrokinetic Decontamination for Concrete Contaminated with Cobalt and Cesium

International Nuclear Information System (INIS)

Kim, Gye Nam; Yang, Byeong Il; Choi, Wang Kyu; Lee, Kune Woo; Hyeon, Jay Hyeok

2009-01-01

A great volume of radioactive concrete is generated during the operation and the decommissioning of nuclear facilities. The washing-electrokinetic technology in this study, which combined an electrokinetic method and a washing method, was developed to decontaminate the concrete generated in nuclear facilities. The results of only an electrokinetic decontamination for the concrete showed that cobalt was removed to below 1% from the concrete due to its high pH. Therefore, the washing electrokinetic technology was applied to lower the pH of the concrete. Namely, when the concrete was washed with 3 M of hydrochloric acid for 4 hours (0.17 day), the CaCO 3 in the concrete was decomposed into CO 2 and the pH of the concrete was reduced to 3.7, and the cobalt and cesium in the concrete were removed by up to 85.0% and 76.3% respectively. Next, when the washed concrete was decontaminated by the electrokinetic method with 0.01M of acetic acid in the 1L electrokinetic equipment for 14.83 days, the cobalt and the cesium in the concrete were both removed by up to 99.7% and 99.6% respectively. The removal efficiencies of the cobalt and cesium by 0.01M of acetic acid were increased more than those by 0.05M of acetic acid due to the increase of the concrete zeta potential. The total effluent volume generated from the washing-electrokinetic decontamination was 11.55L (7.2ml/g).

Application to electrokinetic data to test the adsorption models

Energy Technology Data Exchange (ETDEWEB)

Kosmulski, M. [Abo Akademi Univ. (Finland). Dept. of Physical Chemistry; Technical Univ. of Lublin, Dept. of Electrochemistry (Poland); Eriksson, P.; Gustafsson, J.; Rosenholm, J.B. [Abo Akademi Univ. (Finland). Dept. of Physical Chemistry

2000-07-01

The effect of adsorption of Gd(III) on the electrokinetic potential of silica (Aerosil, 390 m{sup 2}/g) was studied at various Gd(III) concentrations (ranging from 10{sup -6} to 10{sup -2} mol dm{sup -3}) and at four different solid to liquid ratios (ranging from 0.05 to 8% of silica by weight). Up to some critical concentration of trivalent cations, their effect on the electrokinetic potential of silica is negligible and the sign is negative over the entire studied pH range. This critical concentration increases when the solid to liquid ratio increases. When Gd(III) concentration exceeds the critical value, the magnitude of the negative electrokinetic potential of silica is reduced. This effect is substantial at pH 6 but it is rather insignificant when the pH is very high (pH > 8) or very low (pH < 4). When the Gd(III) concentration is even higher, the sign of the electrokinetic potential is reversed to positive over certain pH range, which depends on the solid to liquid ratio and Gd(III) concentration. The shape of experimental electrokinetic curves of silica in the presence of trivalent cations often shows maximums and double isoelectric points, thus, it is very complex in comparison with the shape of the percentage of uptake vs. pH curves. Therefore, a test of an adsorption model based on electrokinetic curves is much more demanding than a test based merely on uptake vs. pH curves. The parameters of surface complexation model (SCM) derived from analysis of a large set of uptake curves were used to predict the course of electrokinetic curves. The calculated and experimentally observed maximums and isoelectric points do not exactly match (a difference up to one pH unit), but the model curves qualitatively reflect the trends observed in electokinetic experiments. (orig.)

Electrokinetic applications for environmental restoration, waste volume reduction, and contaminant containment systems

International Nuclear Information System (INIS)

Lomasney, H.L.; Lomasney, C.A.

1996-01-01

In the US and all over the world, following over 50 years of nuclear arms production operations, the magnitude of resultant environmental damage is only beginning to surface. The US Department of Energy estimates that by the year 2070, the total volume of high-level waste, transuranic waste, low-level waste, and low-level mixed waste, generated as a result of past and current nuclear activities, will exceed 20 million cubic meters. In Russia, it is reported that more than 30% of all groundwater is contaminated with agricultural and industrial chemical waste. Government agencies today are faced with the responsibility of developing technologies that are suitable for dealing with severe environmental contamination and accumulating waste inventories. In response to this demand, applications of electrokinetics have emerged in the field of environmental waste management as alternatives for environmental decontamination and ecological protection. Electrokinetics involves the movement of charged species under the influence of an applied electric field and is applicable in several areas of environmental waste management, including cleanup of soil and groundwater, barrier detection, and emergency or protective fencing. The worldwide interest in this technology has steadily escalated over the past decade. Today, state-of-the-art applications of electrokinetics have been demonstrated in the US, The Netherlands, Russia, The Ukraine, and India. This paper addresses the latest advances in the various applications of this technology as well as the most significant breakthroughs in the history of electrokinetics

An improved electrokinetic method to consolidate porous materials

DEFF Research Database (Denmark)

Feijoo, Jorge; Ottosen, Lisbeth M.; Nóvoa, X. R.

2017-01-01

the consolidation using commercial products have some limitations, such as: (1) low penetrability; (2) no chemical and mineralogical affinity with the material to treat and (3) release of toxic compounds (VOCs), during the solvent evaporation. In the last years, a new consolidation method based on electrokinetic...... the pH of the solutions in contact with the porous material, which can damage it and (2) it is difficult to determine in which area the consolidation takes place. In this study an electrokinetic consolidation method, which has two steps between which the current is reversed, is proposed to solve all...... techniques was developed. This method allows filling some pores by the precipitation of an inorganic compound. As a result the method allows increasing the penetration depth of current consolidation treatments. However, this method needs to be improved since: (1) no special care is taking in controlling...

Electrokinetic Power Generation from Liquid Water Microjets

Energy Technology Data Exchange (ETDEWEB)

Duffin, Andrew M.; Saykally, Richard J.

2008-02-15

Although electrokinetic effects are not new, only recently have they been investigated for possible use in energy conversion devices. We have recently reported the electrokinetic generation of molecular hydrogen from rapidly flowing liquid water microjets [Duffin et al. JPCC 2007, 111, 12031]. Here, we describe the use of liquid water microjets for direct conversion of electrokinetic energy to electrical power. Previous studies of electrokinetic power production have reported low efficiencies ({approx}3%), limited by back conduction of ions at the surface and in the bulk liquid. Liquid microjets eliminate energy dissipation due to back conduction and, measuring only at the jet target, yield conversion efficiencies exceeding 10%.

Electrokinetic demonstration at Sandia National Laboratories: Use of transference numbers for site characterization and process evaluation

International Nuclear Information System (INIS)

Lindgren, E.R.; Mattson, E.D.

1997-01-01

Electrokinetic remediation is generally an in situ method using direct current electric potentials to move ionic contaminants and/or water to collection electrodes. The method has been extensively studied for application in saturated clayey soils. Over the past few years, an electrokinetic extraction method specific for sandy, unsaturated soils has been developed and patented by Sandia National Laboratories. A RCRA RD ampersand D permitted demonstration of this technology for the in situ removal of chromate contamination from unsaturated soils in a former chromic acid disposal pit was operated during the summer and fall of 1996. This large scale field test represents the first use of electrokinetics for the removal of heavy metal contamination from unsaturated soils in the United States and is part of the US EPA Superfund Innovative Technology Evaluation (SITE) Program. Guidelines for characterizing a site for electrokinetic remediation are lacking, especially for applications in unsaturated soil. The transference number of an ion is the fraction of the current carried by that ion in an electric field and represents the best measure of contaminant removal efficiency in most electrokinetic remediation processes. In this paper we compare the transference number of chromate initially present in the contaminated unsaturated soil, with the transference number in the electrokinetic process effluent to demonstrate the utility of evaluating this parameter

Electrokinetic remediation on cadmium (CD) spiked soils

Energy Technology Data Exchange (ETDEWEB)

Sah Jy-Gau [Dept. of Environmental Science and Engineering, National Pingtung Univ. of Science and Technology, Pingtung (Taiwan); Yu Lin, L. [Dept. of Civil and Environmental Engineering, Christian Bros. Univ. Memphis, TN (United States)

2001-07-01

The objective of this study is to examine several variables, such as soil pH, adsorption capacity, fraction of Cd in soils, and organic content for Cd removal in contaminated soil using electrokinetic technology. Two different experimental modules were constructed in the laboratory. In the small module, most Cd was able to move and concentrate at or near the cathode zone in acidic soil and neutral soil under 8 volts after 30 days of electrification. However, the Cd removal efficiency did not improve even when the alkaline soil was soaked in stronger acid solutions. The results indicated that the removal efficiencies were influenced not only by the pH of conducting solutions, but also the pH of the soils. The removal efficiencies of Cd were reduced when a portion of organic peat moss was added into the soils. The increases of organic content in the soils inhibit the removal efficiency in electrokinetic technology. In the larger scale module, the removal efficiency of Cd was lower than that in the smaller module during a short period of time. Nevertheless, the efficiency was improved in the larger module while 16 volts electric pressure and 180 days were applied to the module. The results also showed that the sequence of removal efficiency of the three soils in larger module followed the changes of soil pH. From this study, it concluded that electrokinetic technology has a highly potential to removal Cd in contaminated soils. Within these influence variable studies, the soil pH and organic content are the most important factor in electrokinetic technology. Keywords: Electrokinetic Technique, Heavy Metal, Cd, Soil Remediation. (orig.)

Enhanced electrokinetic remediation of fluorine-contaminated soil by applying an ammonia continuous circulation system

Energy Technology Data Exchange (ETDEWEB)

Zhu, Shufa; Zhou, Ming; Zhang, Shuangyan [Henan University of Science and Technology, Luoyang (China)

2016-02-15

The objective of this research was to investigate the effects of ammonia continuous circulation enhanced electrokinetic remediation of fluorine contaminated soil and to analyze its influence on soil pH after remediation. An experimental study was carried out in self-made electrokinetic apparatus. The voltage gradient was set at 1.0V/cm and ammonia water with different concentrations was used as electrolyte which circulated in series. Comparative studies were made by using deionized water as electrolyte which circulated separately in one experiment and continuously in another. According to the experiment the continuous circulation of ammonia water increased the current value during the remediation process and maintained current through the soil cell stabler, which not only increased fluorine migration but also reduced energy consumption. Among the given ammonia concentrations (0, 0.01, 0.1 and 0.2mol/L) the removal rate increased with ammonia concentration. 0.2mol/L had the highest current (26.8mA), and the removal rate amounted up to 57.3%. By using ammonia circulation enhanced electrokinetic technology, the difference between pH values of cathode soil and anode soil became smaller. Ammonia continuous circulation enhanced electrokinetics can effectively remediate fluorine contaminated soil and the residual ammonia in the soil can also improve soil fertility.

Electrokinetic treatment of contaminated soils, sludges, and lagoons

International Nuclear Information System (INIS)

Wittle, J.K.; Pamukcu, S.

1993-04-01

The electrokinetic process is an emerging technology for in-situ soil decontamination, in which chemical species, both ionic and nonionic are transported to an electrode site in soil. These products are subsequently removed from the ground via collection systems engineered for each specific application. Electrokinetics refer to movement of water, ions and charged particles relative to one another under the action of an applied direct current electric field. In a porous compact matrix of surface charged particles such as soil, the ion containing pore fluid may be made to flow to collection sites under the applied field. This report describes the effort undertaken to investigate electrokinetically enhanced transport of soil contaminants in synthetic systems. These systems consisted of clay or clay-sand mixtures containing known concentration of a selected heavy metal salt solution or an organic compound. Metals, surrogate radio nuclides and organic compounds evaluated in the program were representatives of those found at a majority of DOE sites. Degree of removal of these metals from soil by the electrokinetic treatment process was assessed through the metal concentration profiles generated across the soil between the electrodes. The best removals, from about 85 to 95% were achieved at the anode side of the soil specimens. Transient pH change had an effect on the metal movement via transient creation of different metal species with different ionic mobilities, as well as changing of the surface characteristics of the soil medium

Electrokinetic Amendment in Phytoremediation of Mixed Contaminated Soil

International Nuclear Information System (INIS)

Chirakkara, Reshma A.; Reddy, Krishna R.; Cameselle, Claudio

2015-01-01

This study examines the effects of electrokinetic amendments for phytoremediation of mixed contaminated soil where typical silty clay soil was spiked with organic contaminants (naphthalene and phenanthrene) and heavy metal (lead, cadmium and chromium). The contaminated soil was treated with compost and placed in electrokinetic cells, which were seeded with oat plant or sunflower. Thirty days after germination, 25 V alternating current was applied to selected cells using graphite electrodes for 3 h per day. The plants were harvested after a growth period of 61 days. One cell remained unplanted to evaluate the effect of the electric current on the soil, alone. The results confirm a significant reduction of heavy metals and organic contaminants in soil. However, there was no noticeable improvement of heavy metal phytoextraction or PAH degradation due to the application of electric field despite the increase in biomass production by the plants subjected to the electric current. The electric potential application time and frequency are suggested to be increased to have noticeable effects in heavy metal uptake and PAHs degradation.

An electrokinetic pressure sensor

International Nuclear Information System (INIS)

Kim, Dong-Kwon; Kim, Sung Jin; Kim, Duckjong

2008-01-01

A new concept for a micro pressure sensor is demonstrated. The pressure difference between the inlet and the outlet of glass nanochannels is obtained by measuring the electrokinetically generated electric potential. To demonstrate the proposed concept, experimental investigations are performed for 100 nm wide nanochannels with sodium chloride solutions having various concentrations. The proposed pressure sensor is able to measure the pressure difference within a 10% deviation from linearity. The sensitivity of the electrokinetic pressure sensor with 10 −5 M sodium chloride solution is 18.5 µV Pa −1 , which is one order of magnitude higher than that of typical diaphragm-based pressure sensors. A numerical model is presented for investigating the effects of the concentration and the channel width on the sensitivity of the electrokinetic pressure sensor. Numerical results show that the sensitivity increases as the concentration decreases and the channel width increases

Electrokinetic desalination of protruded areas of stone avoiding the direct contact with electrodes

DEFF Research Database (Denmark)

Feijoo, J.; Matyscák, O.; Ottosen, Lisbeth M.

2017-01-01

of the sandstone highly contaminated with salts. Therefore, these results confirmed that it was possible to desalinate the sandstone using electrokinetic methods without the need to put in contact the affected areas with the equipment, reducing the possibility of altering it by manipulation.......Soluble salts are considered one of the main deterioration factors of porous building materials such as rocks, bricks or granites. The desalination treatments currently used in order to mitigate this alteration process are usually applied directly on the affected areas, which have often a low...... degree of cohesion precisely due to the deteriorating effect of the salts. The present study aimed to investigate the evaluation of a new approach based on electrokinetic techniques to desalinate rocks in monuments, specifically to desalinate carved reliefs. The procedure avoids the direct contact...

Electrokinetic enhancement of phenanthrene biodegradation in creosote-polluted clay soil

International Nuclear Information System (INIS)

Niqui-Arroyo, Jose-Luis; Bueno-Montes, Marisa; Posada-Baquero, Rosa; Ortega-Calvo, Jose-Julio

2006-01-01

Given the difficulties caused by low-permeable soils in bioremediation, a new electrokinetic technology is proposed, based on laboratory results with phenanthrene, to afford bioremediation of polycyclic aromatic hydrocarbons (PAH) in clay soils. Microbial activity in a clay soil historically polluted with creosote was promoted using a specially designed electrokinetic cell with a permanent anode-to-cathode flow and controlled pH. The rates of phenanthrene losses during treatment were tenfold higher in soil treated with an electric field than in the control cells without current or microbial activity. Results from experiments with Tenax-assisted desorption and mineralization of 14 C-labeled phenanthrene indicated that phenanthrene biodegradation was limited by mass-transfer of the chemical. We suggest that the enhancement effect of the applied electric field on phenanthrene biodegradation resulted from mobilization of the PAH and nutrients dissolved in the soil fluids. - Electrokinetic bioremediation is a potentially effective technology to treat PAH-polluted, clay-rich soils

Automated electric valve for electrokinetic separation in a networked microfluidic chip.

Science.gov (United States)

Cui, Huanchun; Huang, Zheng; Dutta, Prashanta; Ivory, Cornelius F

2007-02-15

This paper describes an automated electric valve system designed to reduce dispersion and sample loss into a side channel when an electrokinetically mobilized concentration zone passes a T-junction in a networked microfluidic chip. One way to reduce dispersion is to control current streamlines since charged species are driven along them in the absence of electroosmotic flow. Computer simulations demonstrate that dispersion and sample loss can be reduced by applying a constant additional electric field in the side channel to straighten current streamlines in linear electrokinetic flow (zone electrophoresis). This additional electric field was provided by a pair of platinum microelectrodes integrated into the chip in the vicinity of the T-junction. Both simulations and experiments of this electric valve with constant valve voltages were shown to provide unsatisfactory valve performance during nonlinear electrophoresis (isotachophoresis). On the basis of these results, however, an automated electric valve system was developed with improved valve performance. Experiments conducted with this system showed decreased dispersion and increased reproducibility as protein zones isotachophoretically passed the T-junction. Simulations of the automated electric valve offer further support that the desired shape of current streamlines was maintained at the T-junction during isotachophoresis. Valve performance was evaluated at different valve currents based on statistical variance due to dispersion. With the automated control system, two integrated microelectrodes provide an effective way to manipulate current streamlines, thus acting as an electric valve for charged species in electrokinetic separations.

Surfactant-enhanced electrokinetic remediation of soil contaminated with hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Yang, J.W.; Park, J.Y.; Lee, H.H.; Cho, H.J. [Dept. of Chemical Engineering, Korea Advanced Inst. of Science and Technology, Taejon (Korea)

2001-07-01

Removal of hydrophobic organic contaminants (HOCs) using electrokinetic method was studied in a model system. Kaolinite and phenanthrene were selected as the model clay soil and representative HOC. Three different types of surfactants, APG (alkyl polyglucoside), Brij30 (polyoxyethylene 4 lauryl ether), and SDS (sodium dodecyl sulfate), were used to enhance the solubility of HOCs. Electrokinetic (EK) column experiments were performed using water, surfactant solution, and acetate buffer solution under a constant current condition. Voltage and flow through the soil system were interpreted with time. Electrolyte pH at the anode and cathode compartments was observed for operation time. Removal efficiency of phenanthrene was examined after the end of EK operation during 2, 4, and 6 weeks. (orig.)

EREM 2001 - 3. symposium and status report on electrokinetic remediation

Energy Technology Data Exchange (ETDEWEB)

Czurda, C.; Haus, R. (eds.); Hoetzl, H.

2001-07-01

Papers have been submitted by authors from around the world, reflecting the worldwide interest in electrokinetic remediation techniques. Therefore the symposium series plays a significant role in the presentation of recent advancements in electrochemical decontamination of polluted sediments on both scientific and technical level. In the field of potential cost-saving, innovative in-situ remediation technologies electrokinetics are already identified throughout the world. The main topics of the symposium are: electrokinetic models, electrokinetic transport processes, technical installation, combination of electroremediation with different remediation methods and the application in various electrokinetic field test demonstrations.

DEMONSTRATION BULLETIN: IN SITU ELECTROKINETIC EXTRACTION SYSTEM - SANDIA NATIONAL LABORATORIES

Science.gov (United States)

Sandia National Laboratories (SNL) has developed an in situ soil remediation system that uses electrokinetic principles to remediate hexavalent chromium-contaminated unsaturated or partially saturated soils. The technology involves the in situ application of direct current to the...

Researches in increase of efficiency of electrokinetic process of ground cleaning from radionuclides

International Nuclear Information System (INIS)

Prozorov, L.B.; Shcheglov, M.Y.; Nikolaevsky, V.B.; Tkachenko, A.V.

2003-01-01

Potentially perspective method of decontamination of ground is electrokinetic method, which basic advantage consists in an opportunity of its application for clearing ground with low filtering by ability directly on a place of local contaminated (in situ). Thus moving the large volumes of the contaminated ground is excluded. Base of this method is the processes of electromigration and electro-osmotic, proceeding in a contaminated ground lay at imposing an electrical field of a constant current. Electrokinetic method of cleaning of ground from radionuclides provides their transfer in water-soluble, mobile form, carry as positive or negative ions under influence of an electrical field into electrode chambers with their subsequent recycling.Electrokinetic method in practice can be realized as follows: in the contaminated ground establish special electrode devices, fill their electrolyte and connect to a source of a constant current. Formed in the anode device as a result of electrochemical decomposition of water the ions of hydrogen under action of an electrical field move to the cathode, thus cooperate with a ground and superside cations of radioactive elements. Desorbed cations of contaminate act in catholyte, which periodically or continuously is exposed to clearing, for example, on sorption column. Last years the experts MosNPO Radon carry out complex researches directed on development of electrokinetic technology of cleaning ground from radionuclides and heavy metals. To the present time laboratory and bench tests of electrokinetic method are carried out. The basic attention at study of process of cleaning was given to objects contaminated Cs-137, most difficult recovery an element, which is strongly fixed by clay minerals and can enter into crystal structure. (authors)

Electrokinetic copper and iron migration in anaerobic granular sludge

NARCIS (Netherlands)

Virkutyte, J.; Sillanpää, M.J.; Lens, P.N.L.

2006-01-01

The application of low-level direct electric current (0.15 mA cm¿2) as an electrokinetic technique to treat copper-contaminated mesophilic anaerobic granular sludge was investigated. The sludge was obtained from a full scale UASB reactor treating paper-mill wastewater and was artificially

Recent Progress and Perspectives in the Electrokinetic Characterization of Polyelectrolyte Films

Directory of Open Access Journals (Sweden)

Ralf Zimmermann

2015-12-01

Full Text Available The analysis of the charge, structure and molecular interactions of/within polymeric substrates defines an important analytical challenge in materials science. Accordingly, advanced electrokinetic methods and theories have been developed to investigate the charging mechanisms and structure of soft material coatings. In particular, there has been significant progress in the quantitative interpretation of streaming current and surface conductivity data of polymeric films from the application of recent theories developed for the electrohydrodynamics of diffuse soft planar interfaces. Here, we review the theory and experimental strategies to analyze the interrelations of the charge and structure of polyelectrolyte layers supported by planar carriers under electrokinetic conditions. To illustrate the options arising from these developments, we discuss experimental and simulation data for plasma-immobilized poly(acrylic acid films and for a polyelectrolyte bilayer consisting of poly(ethylene imine and poly(acrylic acid. Finally, we briefly outline potential future developments in the field of the electrokinetics of polyelectrolyte layers.

Influence of temperature and hydraulic conductivity of soil on electrokinetic decontamination

International Nuclear Information System (INIS)

Kim, Gye-Nam; Kim, Seung-Soo; Jeong, Jung-Whan; Choi, Jong-Won

2016-01-01

The electrokinetic process holds great promise for the decontamination of contaminated soil because it has a high removal efficiency and is time-effective for low permeability. Electrokinetic decontamination can be used to treat soil contaminated with inorganic species and radionuclides. The main mechanisms of a contaminant's movement in an electrical field involved in electrokinetic technology are the electro-migration of the ionic species and electro-osmosis. Electro-migration probably contributes significantly to the removal of contaminants, especially at high concentrations of ionic contaminants and/or a high hydraulic permeability of soil. The cathode reaction should be depolarized to avoid the generation of hydroxides and their transport in soil. The selected liquid, also known as a purging reagent, should induce favorable pH conditions in soil, and/or interact with the incorporated heavy metals so that these heavy metals are removed from the soil. The removal efficiencies of uranium from contaminated soil in manufactured laboratory electrokinetic decontamination equipment were proportional to the elapsed time. The removal efficiencies of uranium for 2 days were 77-87%. In addition, the removal efficiencies according to the elapsed time after 2 days were reduced. When 75, 80, and 85℃ electrolyte temperatures in the cathode chamber were applied, the time required for the removal efficiency of uranium to reach 92% was 6, 5 and 4 days

Influence of temperature and hydraulic conductivity of soil on electrokinetic decontamination

Energy Technology Data Exchange (ETDEWEB)

Kim, Gye-Nam; Kim, Seung-Soo; Jeong, Jung-Whan; Choi, Jong-Won [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2016-10-15

The electrokinetic process holds great promise for the decontamination of contaminated soil because it has a high removal efficiency and is time-effective for low permeability. Electrokinetic decontamination can be used to treat soil contaminated with inorganic species and radionuclides. The main mechanisms of a contaminant's movement in an electrical field involved in electrokinetic technology are the electro-migration of the ionic species and electro-osmosis. Electro-migration probably contributes significantly to the removal of contaminants, especially at high concentrations of ionic contaminants and/or a high hydraulic permeability of soil. The cathode reaction should be depolarized to avoid the generation of hydroxides and their transport in soil. The selected liquid, also known as a purging reagent, should induce favorable pH conditions in soil, and/or interact with the incorporated heavy metals so that these heavy metals are removed from the soil. The removal efficiencies of uranium from contaminated soil in manufactured laboratory electrokinetic decontamination equipment were proportional to the elapsed time. The removal efficiencies of uranium for 2 days were 77-87%. In addition, the removal efficiencies according to the elapsed time after 2 days were reduced. When 75, 80, and 85℃ electrolyte temperatures in the cathode chamber were applied, the time required for the removal efficiency of uranium to reach 92% was 6, 5 and 4 days.

Nonlinear electrokinetics at large voltages

Energy Technology Data Exchange (ETDEWEB)

Bazant, Martin Z [Department of Chemical Engineering and Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Sabri Kilic, Mustafa; Ajdari, Armand [Department of Mathematics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Storey, Brian D [Franklin W Olin College of Engineering, Needham, MA 02492 (United States)], E-mail: bazant@mit.edu

2009-07-15

The classical theory of electrokinetic phenomena assumes a dilute solution of point-like ions in chemical equilibrium with a surface whose double-layer voltage is of order the thermal voltage, k{sub B}T/e=25 mV. In nonlinear 'induced-charge' electrokinetic phenomena, such as ac electro-osmosis, several volts {approx}100k{sub B}T/e are applied to the double layer, and the theory breaks down and cannot explain many observed features. We argue that, under such a large voltage, counterions 'condense' near the surface, even for dilute bulk solutions. Based on simple models, we predict that the double-layer capacitance decreases and the electro-osmotic mobility saturates at large voltages, due to steric repulsion and increased viscosity of the condensed layer, respectively. The former suffices to explain observed high-frequency flow reversal in ac electro-osmosis; the latter leads to a salt concentration dependence of induced-charge flows comparable to experiments, although a complete theory is still lacking.

Electrokinetic Particle Transport in Micro-Nanofluidics Direct Numerical Simulation Analysis

CERN Document Server

Qian, Shizhi

2012-01-01

Numerous applications of micro-/nanofluidics are related to particle transport in micro-/nanoscale channels, and electrokinetics has proved to be one of the most promising tools to manipulate particles in micro/nanofluidics. Therefore, a comprehensive understanding of electrokinetic particle transport in micro-/nanoscale channels is crucial to the development of micro/nano-fluidic devices. Electrokinetic Particle Transport in Micro-/Nanofluidics: Direct Numerical Simulation Analysis provides a fundamental understanding of electrokinetic particle transport in micro-/nanofluidics involving elect

Assessment and Comparison of Electrokinetic and Electrokinetic-bioremediation Techniques for Mercury Contaminated Soil

Science.gov (United States)

Azhar, A. T. S.; Nabila, A. T. A.; Nurshuhaila, M. S.; Zaidi, E.; Azim, M. A. M.; Farhana, S. M. S.

2016-11-01

Landfills are major sources of contamination due to the presence of harmful bacteria and heavy metals. Electrokinetic-Bioremediation (Ek-Bio) is one of the techniques that can be conducted to remediate contaminated soil. Therefore, the most prominent bacteria from landfill soil will be isolated to determine their optimal conditions for culture and growth. The degradation rate and the effectiveness of selected local bacteria were used to reduce soil contamination. Hence, this enhances microbiological activities to degrade contaminants in soil and reduce the content of heavy metals. The aim of this study is to investigate the ability of isolated bacteria (Lysinibacillus fusiformis) to remove mercury in landfill soil. 5 kg of landfill soil was mixed with deionized water to make it into slurry condition for the purpose of electrokinetic and bioremediation. This remediation technique was conducted for 7 days by using 50 V/m of electrical gradient and Lysinibacillus fusiformis bacteria was applied at the anode reservoir. The slurry landfill soil was located at the middle of the reservoir while distilled water was placed at the cathode of reservoir. After undergoing treatment for 7 days, the mercury analyzer showed that there was a significant reduction of approximately up to 78 % of mercury concentration for the landfill soil. From the results, it is proven that electrokinetic bioremediation technique is able to remove mercury within in a short period of time. Thus, a combination of Lysinibacillus fusiformis and electrokinetic technique has the potential to remove mercury from contaminated soil in Malaysia.

Electrokinetics and soil decontamination: concepts and overview (Review

Directory of Open Access Journals (Sweden)

Mohammed A. Karim

2014-12-01

Full Text Available Electrokinetic decontamination and extraction have been proven to be one of the most viable, cost effective and emerging techniques in removing contaminants, especially heavy metals from soils for about last five decades. Basic concepts and an overview of the electrokinetic extraction processes and their potential applications in geotechnical and geoenvironmental engineering have been reviewed based on the literature and presented in this paper. Primarily, theoretical and laboratory experimental studies related to electroreclamation of soils are summarised in brief with basic concepts of electrokinetic processes. The paper has been divided into different sections that include history of electrokinetics, background and concepts, modelling, parameter effects, instrumentation, contaminant extraction, field applications, and summary and recommendation. Based on the review it is obvious that the field application of electrokinetic technology to remediate heavy metal contaminated soils /sediments is very limited and site specific. Additional laboratory studies and more pilot- and full-scale information from field applications are critical to the further understanding of the technology and to customize the process in different field conditions.

Lead (II) removal from natural soils by enhanced electrokinetic remediation.

Science.gov (United States)

Altin, Ahmet; Degirmenci, Mustafa

2005-01-20

Electrokinetic remediation is a very effective method to remove metal from fine-grained soils having low adsorption and buffering capacity. However, remediation of soil having high alkali and adsorption capacity via the electrokinetic method is a very difficult process. Therefore, enhancement techniques are required for use in these soil types. In this study, the effect of the presence of minerals having high alkali and cation exchange capacity in natural soil polluted with lead (II) was investigated by means of the efficiency of electrokinetic remediation method. Natural soil samples containing clinoptilolite, gypsum and calcite minerals were used in experimental studies. Moreover, a sample containing kaolinite minerals was studied to compare with the results obtained from other samples. Best results for soils bearing alkali and high sorption capacity minerals were obtained upon addition of 3 mol AcH and application of 20 V constant potential after a remediation period of 220 h. In these test conditions, lead (II) removal efficiencies for these samples varied between 60% and 70% up to 0.55 normalized distance. Under the same conditions, removal efficiencies in kaolinite sample varied between 50% and 95% up to 0.9 normalized distance.

Theory of electrostatics and electrokinetics of soft particles

Directory of Open Access Journals (Sweden)

Hiroyuki Ohshima

2009-01-01

Full Text Available We investigate theoretically the electrostatics and electrokinetics of a soft particle, i.e. a hard particle covered with an ion-penetrable surface layer of polyelectrolytes. The electric properties of soft particles in an electrolyte solution, which differ from those of hard particles, are essentially determined by the Donnan potential in the surface layer. In particular, the Donnan potential plays an essential role in the electrostatics and electrokinetics of soft particles. Furthermore, the concept of zeta potential, which is important in the electrokinetics of hard particles, loses its physical meaning in the electrokinetics of soft particles. In this review, we discuss the potential distribution around a soft particle, the electrostatic interaction between two soft particles, and the motion of a soft particle in an electric field.

Electrokinetic treatment of contaminated soils, sludges, and lagoons. Final report

Energy Technology Data Exchange (ETDEWEB)

Wittle, J.K. [Electro-Petroleum, Inc., Wayne, PA (United States); Pamukcu, S. [Lehigh Univ., Bethlehem, PA (United States). Dept. of Civil Engineering

1993-04-01

The electrokinetic process is an emerging technology for in-situ soil decontamination, in which chemical species, both ionic and nonionic are transported to an electrode site in soil. These products are subsequently removed from the ground via collection systems engineered for each specific application. Electrokinetics refer to movement of water, ions and charged particles relative to one another under the action of an applied direct current electric field. In a porous compact matrix of surface charged particles such as soil, the ion containing pore fluid may be made to flow to collection sites under the applied field. This report describes the effort undertaken to investigate electrokinetically enhanced transport of soil contaminants in synthetic systems. These systems consisted of clay or clay-sand mixtures containing known concentration of a selected heavy metal salt solution or an organic compound. Metals, surrogate radio nuclides and organic compounds evaluated in the program were representatives of those found at a majority of DOE sites. Degree of removal of these metals from soil by the electrokinetic treatment process was assessed through the metal concentration profiles generated across the soil between the electrodes. The best removals, from about 85 to 95% were achieved at the anode side of the soil specimens. Transient pH change had an effect on the metal movement via transient creation of different metal species with different ionic mobilities, as well as changing of the surface characteristics of the soil medium.

Modeling electrokinetics in ionic liquids: General

Energy Technology Data Exchange (ETDEWEB)

Wang, Chao [Physical and Computational Science Directorate, Pacific Northwest National Laboratory, Richland WA USA; Bao, Jie [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland WA USA; Pan, Wenxiao [Department of Mechanical Engineering, University of Wisconsin-Madison, Madison WI USA; Sun, Xin [Physical and Computational Science Directorate, Pacific Northwest National Laboratory, Richland WA USA

2017-04-07

Using direct numerical simulations we provide a thorough study on the electrokinetics of ionic liquids. In particular, the modfied Poisson-Nernst-Planck (MPNP) equations are solved to capture the crowding and overscreening effects that are the characteristics of an ionic liquid. For modeling electrokinetic flows in an ionic liquid, the MPNP equations are coupled with the Navier-Stokes equations to study the coupling of ion transport, hydrodynamics, and electrostatic forces. Specifically, we consider the ion transport between two parallel plates, charging dynamics in a 2D straight-walled pore, electro-osmotic ow in a nano-channel, electroconvective instability on a plane ion-selective surface, and electroconvective ow on a curved ion-selective surface. We discuss how the crowding and overscreening effects and their interplay affect the electrokinetic behaviors of ionic liquids in these application problems.

Electrokinetic remediation of copper mine tailings

DEFF Research Database (Denmark)

Hansen, Henrik K.; Rojo, Adrián; Ottosen, Lisbeth M.

2007-01-01

Important process parameters to optimize in electrokinetic soil remediation are those influencing remediation time and power consumption since these directly affect the cost of a remediation action. This work shows how the electrokinetic remediation (EKR) process could be improved by implementing...... bipolar electrodes in the porous material. The bipolar electrodes in EKR meant two improvements: (1) a shorter migration pathway for the contaminant, and (2) an increased electrical conductivity in the remediation system. All together the remediation proceeded faster with lower electrical resistance than...... in similar experiments but without the bipolar electrodes. The new electrokinetic remediation design was tested on copper mine tailings with different applied electric fields, remediation times and pre-treatment. The results showed that the copper removal was increased from 8% (applying 20V for 8 days...

Geotechnical behaviour of low-permeability soils in surfactant-enhanced electrokinetic remediation.

Science.gov (United States)

López-Vizcaíno, Rubén; Navarro, Vicente; Alonso, Juan; Yustres, Ángel; Cañizares, Pablo; Rodrigo, Manuel A; Sáez, Cristina

2016-01-01

Electrokinetic processes provide the basis of a range of very interesting techniques for the remediation of polluted soils. These techniques consist of the application of a current field in the soil that develops different transport mechanisms capable of mobilizing several types of pollutants. However, the use of these techniques could generate nondesirable effects related to the geomechanical behavior of the soil, reducing the effectiveness of the processes. In the case of the remediation of polluted soils with plasticity index higher than 35, an excessive shrinkage can be observed in remediation test. For this reason, the continued evaporation that takes place in the sample top can lead to the development of cracks, distorting the electrokinetic transport regime, and consequently, the development of the operation. On the other hand, when analyzing silty soils, in the surroundings of injection surfactant wells, high seepages can be generated that give rise to the development of piping processes. In this article methods are described to allow a reduction, or to even eliminate, both problems.

Electrokinetic Stabilisation Method of Soft Clay in Pure System using Electrokinetic Geosynthetic Electrode

Science.gov (United States)

Azhar, A. T. S.; Jefferson, I.; Madun, A.; Abidin, M. H. Z.; Rogers, C. D. F.

2018-04-01

Electrokinetic stabilisation (EKS) method has the ability to solve the problems of soft highly compressibility soil. This study will present the results from an experimental study of EKS on soft soils using inactive kaolinite clay, inert electrode and distilled water (DW) as a pure system mechanism before any chemical stabilisers being used in this research. Therefore, this will provide a baseline study to improve the efficiency of EKS approach. The test model was using inert electrode of Electrokinetic Geosythentic (EKG) developed at the Newcastle University to apply a constant voltage gradient of 50 V/m across a soil sample approximately 400 mm. Distilled water was used at the pore electrolyte fluid compartments supplied under zero hydraulic gradient conditions for the periods of 3, 7 and 14 days. Throughout the monitoring, physical and chemical characteristics were measured. Results from the monitoring data, physical and chemical properties of the pure system showed the development of pH gradient, the changes of electrical conductivity and chemical concentrations with regards to the distance from anode and treatment periods due to the electrochemical effects even though there was no chemical stabilisers were introduced or released from the degradation of electrodes.

Electrokinetic microchannel battery by means of electrokinetic and microfluidic phenomena

Science.gov (United States)

Yang, Jun; Lu, Fuzhi; Kostiuk, Larry W.; Kwok, Daniel Y.

2003-11-01

Pressure-driven flow in a microchannel induces a streaming current due to the presence of an electrical double layer in the interface between the electrolyte solution and channel wall. As the streaming current is of the order of a nano-amphere and is additive, we propose here a method to develop an electrokinetic battery consisting of an array of microchannels that converts the hydrostatic pressure of a liquid into electrical work. We have given oscillating analytical solutions by means of an electrical circuit analysis to model the multi-microchannel battery. Using superposition of the appropriate Fourier series, the derived analytical solutions are useful to predict the current when there is more general time-dependent flow through a microchannel array. To illustrate the idea, we have studied steady-state pressure-driven flow in micropore porous glass filter and compared the results with those predicted from our model. From a 30 cm hydrostatic pressure drop, an external current of 1-2 µA was obtained by means of water passing through the micropore porous glass filter. A larger current can be obtained by simply using a solution with higher salt concentration. This results in a new and potentially useful method of energy conversion by means of an array of microchannels.

Electrokinetic remediation of contaminated soils

International Nuclear Information System (INIS)

Lindgren, E.R.; Kozak, M.W.; Mattson, E.D.

1991-01-01

Electrokinetic remediation of contaminated soil has been demonstrated for saturated and unsaturated sand in preliminary experiments using a novel transport visualization technique. Large anionic organic dyes were mixed with a portion of soil and the rate of electromigration of the dye in an imposed electric field was monitored photographically. One of the fastest current-normalized electromigration rates was measured in the driest sand, which contained 7% water by weight. This moisture content is typical of the moisture content in the unsaturated zone of subsurface native soils found in New Mexico. The characteristics of the electromigration were similar in both the saturated and unsaturated sand. The leading edge of the dye migration front was diffuse while the trailing edge was sharp and concentrated. This and other observed behavior may indicate a concentration effect, where the electromigration rate of dilute dye is greater than that of concentrated dye. The soil left after the trailing edge passed seemed to contain no residual dye in both the saturated and unsaturated cases. The success of demonstrating electromigration of large molecules in unsaturated soil is encouraging and indicates that it may be feasible to remediate in situ anionic heavy metals such as chromate from unsaturated soil with electrokinetic techniques. 23 refs., 7 figs

Electrokinetic remediation of contaminated soils

International Nuclear Information System (INIS)

Lindgren, E.R.; Kozak, M.W.; Mattson, E.D.

1991-01-01

Electrokinetic remediation of contaminated soil has been demonstrated for saturated and unsaturated sand in preliminary experiments using a novel transport visualization technique. Large anionic organic dyes were mixed with a portion of soil and the rate of electromigration of the dye in an imposed electric field was monitored photographically. One of the fastest current-normalized electromigration rates was measured in the driest sand, which contained 7% water by-weight. This moisture content is typical of the moisture content in the unsaturated zone of subsurface native soils found in New Mexico. The characteristics of the electromigration were similar in both the saturated and unsaturated sand. The leading edge of the dye migration front was diffuse while the trailing edge was sharp and concentrated. This and other observed behavior may indicate a concentration effect, where the electromigration rate of dilute dye is greater than that of concentrated dye. The soil left after the trailing edge passed seemed to contain no residual dye in both the saturated and unsaturated cases. The success of demonstrating electromigration of large molecules in unsaturated soil is encouraging and indicates that it may be feasible to remediate in situ anionic heavy metals such as chromate from unsaturated soil with electrokinetic techniques

Electrokinetic pumping and detection of low-volume flows in nanochannels

NARCIS (Netherlands)

Mela, P.; Tas, Niels Roelof; Berenschot, Johan W.; van Nieuwkasteele, Jan William; van den Berg, Albert

2004-01-01

Electrokinetic pumping of low-volume rates was performed on-chip in channels of small cross sectional area and height in the sub-m range. The flow was detected with the current monitoring technique by monitoring the change in resistance of the fluid in the channel upon the electroosmosis-driven

Electrokinetics of diffuse soft interfaces. I. Limit of low Donnan potentials

NARCIS (Netherlands)

Duval, J.F.L.; Leeuwen, van H.P.

2004-01-01

The current theoretical approaches to electrokinetics of gels or polyelectrolyte layers are based on the assumption that the position of the very interface between the aqueous medium and the gel phase is well defined. Within this assumption, spatial profiles for the volume fraction of polymer

Secondary side TSP deposit buildup: lab test investigation focused on electrokinetic considerations

International Nuclear Information System (INIS)

Barale, M.; Guillodo, M.; Foucault, M.; Ryckelynck, N.; Clinard, M-H.; Chahma, F.; Brun, C.; Corredera, G.

2010-01-01

Deposit buildup which caused the clogging of the 'foils' of the upper tube-support-plates (TSP) inside a PWR steam generator of French NPPs in 2006 presents certain similarities with deposits observed in lab tests performed in secondary coolant chemistry at the Technical Centre of AREVA NP in 2002. The mechanism of TSP clogging seems not to present obvious phenomenological links with the fouling of the free span of SG since deposits buildup is quite uniform and is currently related to a surface boiling effect due to the surface heat flux. A specific mechanism could account for TSP clogging. In particular, electrokinetic effects were investigated by EDF-CEIDRE and AREVA NP SAS in the framework of a lab test program started in 2007. The electrokinetic approach is to consider that the coupling of local hydrodynamic and surface electrochemistry could lead to the formation of a very localized and heterogeneous deposit at the leading edge between both TSP and SG tubing material. Electrokinetic effects can lead to the oxidation and/or the precipitation of ferrous ions and to a variation of the electrokinetic potential which can produce strong attraction of iron oxide colloids. These electrokinetic effects are dependent of the T/H and local hydrodynamic conditions and surface electrochemistry explaining. The objective of this EDF-AREVA lab test program is to investigate the role of secondary chemistry coolant (pH, DH, N 2 H 4 , amine, redox) and of the nature of materials (SS, Ni base alloy) on deposit buildup. Properties of oxide surface and zeta potential of oxidized metallic materials have been also determined at temperature to understand their potential contribution on mechanism of TSP clogging in secondary side chemistry coolant. In this paper, a set of specific experiments carried out in this frame have been presented and discussed, paying particular attention to the effects of electrokinetic considerations and surface charges at oxide-solution interfaces

Secondary side TSP deposit buildup: lab test investigation focused on electrokinetic considerations

Energy Technology Data Exchange (ETDEWEB)

Barale, M.; Guillodo, M.; Foucault, M., E-mail: Morgan.Barale@areva.com [AREVA NP SAS, Technical Centre, Le Creusot (France); Ryckelynck, N.; Clinard, M-H.; Chahma, F.; Brun, C. [AREVA NP SAS, Chemistry and Radiochemistry Group, Paris (France); Corredera, G. [Electricite de France, Centre d' Expertise et d' Inspection dans les domaines de la Realisation et de l' Exploitation, Saint-Denis (France)

2010-07-01

Deposit buildup which caused the clogging of the 'foils' of the upper tube-support-plates (TSP) inside a PWR steam generator of French NPPs in 2006 presents certain similarities with deposits observed in lab tests performed in secondary coolant chemistry at the Technical Centre of AREVA NP in 2002. The mechanism of TSP clogging seems not to present obvious phenomenological links with the fouling of the free span of SG since deposits buildup is quite uniform and is currently related to a surface boiling effect due to the surface heat flux. A specific mechanism could account for TSP clogging. In particular, electrokinetic effects were investigated by EDF-CEIDRE and AREVA NP SAS in the framework of a lab test program started in 2007. The electrokinetic approach is to consider that the coupling of local hydrodynamic and surface electrochemistry could lead to the formation of a very localized and heterogeneous deposit at the leading edge between both TSP and SG tubing material. Electrokinetic effects can lead to the oxidation and/or the precipitation of ferrous ions and to a variation of the electrokinetic potential which can produce strong attraction of iron oxide colloids. These electrokinetic effects are dependent of the T/H and local hydrodynamic conditions and surface electrochemistry explaining. The objective of this EDF-AREVA lab test program is to investigate the role of secondary chemistry coolant (pH, DH, N{sub 2}H{sub 4}, amine, redox) and of the nature of materials (SS, Ni base alloy) on deposit buildup. Properties of oxide surface and zeta potential of oxidized metallic materials have been also determined at temperature to understand their potential contribution on mechanism of TSP clogging in secondary side chemistry coolant. In this paper, a set of specific experiments carried out in this frame have been presented and discussed, paying particular attention to the effects of electrokinetic considerations and surface charges at oxide

Remediation of 137Cs contaminated concrete using electrokinetic phenomena and ionic salt washes in nuclear energy contexts.

Science.gov (United States)

Parker, Andrew J; Joyce, Malcolm J; Boxall, Colin

2017-10-15

This work describes the first known the use of electrokinetic treatments and ionic salt washes to remediate concrete contaminated with 137 Cs. A series of experiments were performed on concrete samples, contaminated with K + and 137 Cs, using a bespoke migration cell and an applied electric field (60V potential gradient and current limit of 35mA). Additionally, two samples were treated with an ionic salt wash (≤400molm -3 of KCl) alongside the electrokinetic treatment. The results show that the combined treatment produces removal efficiencies three times higher (>60%) than the electrokinetic treatment alone and that the decontamination efficiency appears to be proportional to the initial degree of contamination. Furthermore, the decontamination efficiencies are equivalent to previous electrokinetic studies that utilised hazardous chemical enhancement agents demonstrating the potential of the technique for use on nuclear licensed site. The results highlight the relationship between the initial contamination concentration within the concrete and achievable removal efficiency of electrokinetic treatment and other treatments. This information would be useful when selecting the most appropriate decontamination techniques for particular contamination scenarios. Copyright © 2017 Elsevier B.V. All rights reserved.

Electrokinetic removal of Pb from tailings and the application of stabilization agents

OpenAIRE

Rajić, Ljiljana; Dalmacija, Božo; Dalmacija, Milena

2012-01-01

In this study, the possibility of applying the certain stabilization agents was investigated in order to improve the electrokinetic treatment of tailings with high concentrations of Pb. Different stabilization agents were inserted in the cathode region in order to improve the immobilisation of Pb ions that migrate towards the cathode, and thus control Pb movement and behaviour. EK treatments were carried out in the electrokinetic setup using the voltage gradient of 1 V/cm. The applied stabili...

Preparation of Janus Particles and Alternating Current Electrokinetic Measurements with a Rapidly Fabricated Indium Tin Oxide Electrode Array.

Science.gov (United States)

Chen, Yu-Liang; Jiang, Hong-Ren

2017-06-23

This article provides a simple method to prepare partially or fully coated metallic particles and to perform the rapid fabrication of electrode arrays, which can facilitate electrical experiments in microfluidic devices. Janus particles are asymmetric particles that contain two different surface properties on their two sides. To prepare Janus particles, a monolayer of silica particles is prepared by a drying process. Gold (Au) is deposited on one side of each particle using a sputtering device. The fully coated metallic particles are completed after the second coating process. To analyze the electrical surface properties of Janus particles, alternating current (AC) electrokinetic measurements, such as dielectrophoresis (DEP) and electrorotation (EROT)- which require specifically designed electrode arrays in the experimental device- are performed. However, traditional methods to fabricate electrode arrays, such as the photolithographic technique, require a series of complicated procedures. Here, we introduce a flexible method to fabricate a designed electrode array. An indium tin oxide (ITO) glass is patterned by a fiber laser marking machine (1,064 nm, 20 W, 90 to 120 ns pulse-width, and 20 to 80 kHz pulse repetition frequency) to create a four-phase electrode array. To generate the four-phase electric field, the electrodes are connected to a 2-channel function generator and to two invertors. The phase shift between the adjacent electrodes is set at either 90° (for EROT) or 180° (for DEP). Representative results of AC electrokinetic measurements with a four-phase ITO electrode array are presented.

Electrokinetics and flocculation studies of coal

Energy Technology Data Exchange (ETDEWEB)

Dhawan, N. [Punjab Engineering College, Chandigarh (India). Dept. of Metallurgical Engineering

2008-07-01

Coal from India contains 25-35 per cent ash content. This leads to high slag volume, lower calorific value and inferior coke. In order to remove ash content, coal is washed, however, it retains some water that makes it difficult to process. Mechanical dewatering is performed in which a large portion of solids is removed while the remainder remains in centrifuge. There is therefore a need to recover solids and water. This paper discussed the use of flocculation and electrokinetic studies such as the determination of the point of zero charge. The experimental studies considered factors such as turbidity, faster settling, and compactness. Flocculation is brought about by the action of high molecular weight materials such as polyelectrolytes, where the material physically forms a bridge between two or more particles, uniting the sold particles into a random, three-dimensional structure, which is loose and porous. This paper also described the materials and methods of the electrokinetic studies on coal samples. Materials that were described included nephelometer, zeta meter, and a flocculator. It was concluded that in selecting the best flocculant, the preference order should be turbidity; settling rate; dosage; and moisture content. 3 refs., 2 tabs., 8 figs.

The removal of Cs-137 from soil using washing-electrokinetic decontamination equipment

International Nuclear Information System (INIS)

Kim, Gyenam; Kim, Seungsoo; Kim, Geunho; Park, Hyemin; Kim, Wansuk; Park, Ukryang; Kwon, Hyeokju; Ryu, Ohha; Moon, Jeikwon

2012-01-01

The radioactive soil at the KAERI radioactive waste storage facility has slightly high hydro-conductivity, and was mainly contaminated with 137 Cs 30-35 years ago. Recently, a soil washing method has been applied to remove 137 Cs from radioactive soil, but it appears that the removal efficiency of 137 Cs had low and a lot of waste solution was generated. Meanwhile, an electrokinetic decontamination method provides high removal efficiency of 137 Cs and generates little waste effluent. Thus, it is suggested that an electrokinetic decontamination method is a suitable technology in consideration of the soil characteristics near South Korean nuclear facilities

Electrokinetic desalination of sandstones for NaCl removal

DEFF Research Database (Denmark)

Ottosen, Lisbeth M.; Christensen, Iben V.

2012-01-01

of reliable methods to remove the damaging salts in order to stop the decay. Electrokinetic desalination of fired clay bricks have previously shown efficient in laboratory scale and in the present work the method is tested for desalination of Cotta and Posta sandstones, which both have lower porosity than...... each stone, but electroosmosis in the poultices may have caused suction/pressure over the interface between stone and poultice causing the differences in poultice water content. The transport numbers for Cl− and Na+ differed in the two stones and were highest in the most porous Cotta sandstone in spite...... of similar high pore water concentrations and the same applied electric current. The hypotheses is that a layered structure of the sandstones could be the cause for this, as the electric current may preferentially flow in certain paths through the stone, which are thus desalinated first. After...

Electrokinetic Control of Viscous Fingering

Science.gov (United States)

Mirzadeh, Mohammad; Bazant, Martin Z.

2017-10-01

We present a theory of the interfacial stability of two immiscible electrolytes under the coupled action of pressure gradients and electric fields in a Hele-Shaw cell or porous medium. Mathematically, our theory describes a phenomenon of "vector Laplacian growth," in which the interface moves in response to the gradient of a vector-valued potential function through a generalized mobility tensor. Physically, we extend the classical Saffman-Taylor problem to electrolytes by incorporating electrokinetic (EK) phenomena. A surprising prediction is that viscous fingering can be controlled by varying the injection ratio of electric current to flow rate. Beyond a critical injection ratio, stability depends only upon the relative direction of flow and current, regardless of the viscosity ratio. Possible applications include porous materials processing, electrically enhanced oil recovery, and EK remediation of contaminated soils.

Acoustically and Electrokinetically Driven Transport in Microfluidic Devices

Science.gov (United States)

Sayar, Ersin

Electrokinetically driven flows are widely employed as a primary method for liquid pumping in micro-electromechanical systems. Mixing of analytes and reagents is limited in microfluidic devices due to the low Reynolds number of the flows. Acoustic excitations have recently been suggested to promote mixing in the microscale flow systems. Electrokinetic flows through straight microchannels were investigated using the Poisson-Boltzmann and Nernst-Planck models. The acoustic wave/fluid flow interactions in a microchannel were investigated via the development of two and three-dimensional dynamic predictive models for flows with field couplings of the electrical, mechanical and fluid flow quantities. The effectiveness and applicability of electrokinetic augmentation in flexural plate wave micropumps for enhanced capabilities were explored. The proposed concept can be exploited to integrate micropumps into complex microfluidic chips improving the portability of micro-total-analysis systems along with the capabilities of actively controlling acoustics and electrokinetics for micro-mixer applications. Acoustically excited flows in microchannels consisting of flexural plate wave devices and thin film resonators were considered. Compressible flow fields were considered to accommodate the acoustic excitations produced by a vibrating wall. The velocity and pressure profiles for different parameters including frequency, channel height, wave amplitude and length were investigated. Coupled electrokinetics and acoustics cases were investigated while the electric field intensity of the electrokinetic body forces and actuation frequency of acoustic excitations were varied. Multifield analysis of a piezoelectrically actuated valveless micropump was also presented. The effect of voltage and frequency on membrane deflection and flow rate were investigated. Detailed fluid/solid deformation coupled simulations of piezoelectric valveless micropump have been conducted to predict the

In-Situ Electrokinetic Remediation for Metal Contaminated Soils

Science.gov (United States)

2001-03-01

phytoremediation , and electrokinetic extraction. The US Army Environmental Center (USAEC) and Engineer Research and Development Center (ERDC...California (CA) List Metals: Antimony, arsenic, barium, beryllium, cadmium, chromium, cobalt, copper, lead, mercury , molybdenum, nickel, selenium...Comparison Technologies with which electrokinetic remediation must compete are "Dig and Haul", Soil Washing, and Phytoremediation . "Dig and haul

Electrokinetic Fingering In Hele-Shaw Cells

Science.gov (United States)

Mirzadeh, Mohammad; Bazant, Martin

2016-11-01

Large scale flow problems in porous media, such as those encountered in underground oil reservoirs, are typically described by the Darcy's law. However, it is well known that many underground rock formations contain surface groups and minerals that dissociate in the presence of water. Convection of these charges by the pressure driven flow can then set up streaming current and streaming potential that affects the flow. Furthermore, electric fields that are often used to enhance oil recovery, e.g. by reducing the oil's viscosity through electro-thermal heating, drive electro-osmotic flows that could set up very large pressure in small pores. The full description of fluid flow thus requires a solution to the fully coupled electrokinetic problem. In their seminal work, Saffman and Taylor showed that the moving interface between two immiscible fluids in a porous medium becomes unstable if pushed by the low-viscosity fluid. Here we report on the role of electrokinetic phenomena on stability of these viscous fronts in Hele-Shaw cells by using analytic as well as numerical approaches. Interestingly, we find that the instability could be suppressed if the right physical conditions are met or otherwise enhanced, leading to greater mixing of two fluids.

The removal of Cs-137 from soil using washing-electrokinetic decontamination equipment

Energy Technology Data Exchange (ETDEWEB)

Kim, Gyenam; Kim, Seungsoo; Kim, Geunho; Park, Hyemin; Kim, Wansuk; Park, Ukryang; Kwon, Hyeokju; Ryu, Ohha; Moon, Jeikwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2012-10-15

The radioactive soil at the KAERI radioactive waste storage facility has slightly high hydro-conductivity, and was mainly contaminated with {sup 137}Cs 30-35 years ago. Recently, a soil washing method has been applied to remove {sup 137}Cs from radioactive soil, but it appears that the removal efficiency of {sup 137}Cs had low and a lot of waste solution was generated. Meanwhile, an electrokinetic decontamination method provides high removal efficiency of {sup 137}Cs and generates little waste effluent. Thus, it is suggested that an electrokinetic decontamination method is a suitable technology in consideration of the soil characteristics near South Korean nuclear facilities.

Hybrid electrokinetic method applied to mix contaminated soil

Energy Technology Data Exchange (ETDEWEB)

Mansour, H.; Maria, E. [Dept. of Building Civil and Environmental Engineering, Concordia Univ., Montreal (Canada)

2001-07-01

Several industrials and municipal areas in North America are contaminated with heavy metals and petroleum products. This mix contamination presents a particularly difficult task for remediation when is exposed in clayey soil. The objective of this research was to find a method to cleanup mix contaminated clayey soils. Finally, a multifunctional hybrid electrokinetic method was investigated. Clayey soil was contaminated with lead and nickel (heavy metals) at the level of 1000 ppm and phenanthrene (PAH) of 600 ppm. Electrokinetic surfactant supply system was applied to mobilize, transport and removal of phenanthrene. A chelation agent (EDTA) was also electrokinetically supplied to mobilize heavy metals. The studies were performed on 8 lab scale electrokinetic cells. The mix contaminated clayey soil was subjected to DC total voltage gradient of 0.3 V/cm. Supplied liquids (surfactant and EDTA) were introduced in different periods of time (22 days, 42 days) in order to optimize the most excessive removal of contaminants. The ph, electrical parameters, volume supplied, and volume discharged was monitored continuously during each experiment. At the end of these tests soil and cathalyte were subjected to physico-chemical analysis. The paper discusses results of experiments including the optimal energy use, removal efficiency of phenanthrene, as well, transport and removal of heavy metals. The results of this study can be applied for in-situ hybrid electrokinetic technology to remediate clayey sites contaminated with petroleum product mixed with heavy metals (e.g. manufacture Gas Plant Sites). (orig.)

Singular deposit formation in PWR due to electrokinetic phenomena - application to SG clogging

Energy Technology Data Exchange (ETDEWEB)

Guillodo, M.; Muller, T.; Barale, M.; Foucault, M. [AREVA NP SAS, Technical Centre (France); Clinard, M.-H.; Brun, C.; Chahma, F. [AREVA NP SAS, Chemistry and Radiochemistry Group (France); Corredera, G.; De Bouvier, O. [Electricite de France, Centre d' Expertise de I' inspection dans les domaines de la Realisation et de l' Exploitation (France)

2009-07-01

The deposits which cause clogging of the 'foils' of the tube support plates (TSP) in Steam Generators (SG) of PWR present two characteristics which put forward that the mechanism at the origin of their formation is different from the mechanism that drives the formation of homogeneous deposits leading to the fouling of the free spans of SG tubes. Clogging occurs near the leading edge of the TSP and the deposits appear as diaphragms localized between both TSP and SG tubing materials, while the major part of the tube/TSP interstice presents little or no significant clogging. This type of deposit seems rather comparable to the ones which were reproduced in Lab tests to explain the flow rate instabilities observed on a French unit during hot shutdown in the 90's. The deposits which cause TSP clogging are owed to a discontinuity of the streaming currents in the vicinity of a surface singularity (orifices, scratches ...) which, in very low conductivity environment, produce local potential variations and/or current loop in the metallic pipe material due to electrokinetic effects. Deposits can be built by two mechanisms which may or not coexist: (i) accumulation of particles stabilized by an electrostatic attraction due to the local variation of electrokinetic potential, and (ii) crystalline growth of magnetite produced by the oxidation of ferrous ions on the anodic branch of a current loop. Lab investigations carried out by AREVA NP Technical Centre since the end of the 90's showed that this type of deposit occurs when the redox potential is higher than a critical value, and can be gradually dissolved when the potential becomes lower than this value which depends on the 'Material - Chemistry' couple. Special emphasis will be given in this paper to the TSP clogging of SG in PWR secondary coolant dealing particularly with the potential strong effect of electrokinetic phenomena in low conductive environment and in high temperature conditions

Applications and theory of electrokinetic enrichment in micro-nanofluidic chips.

Science.gov (United States)

Chen, Xueye; Zhang, Shuai; Zhang, Lei; Yao, Zhen; Chen, Xiaodong; Zheng, Yue; Liu, Yanlin

2017-09-01

This review reports the progress on the recent development of electrokinetic enrichment in micro-nanofluidic chips. The governing equations of electrokinetic enrichment in micro-nanofluidic chips are given. Various enrichment applications including protein analysis, DNA analysis, bacteria analysis, viruses analysis and cell analysis are illustrated and discussed. The advantages and difficulties of each enrichment method are expatiated. This paper will provide a particularly convenient and valuable reference to those who intend to research the electrokinetic enrichment based on micro-nanofluidic chips.

Electrokinetics on superhydrophobic surfaces

International Nuclear Information System (INIS)

Papadopoulos, Periklis; Deng Xu; Vollmer, Doris; Butt, Hans-Jürgen

2012-01-01

On a superhydrophobic surface a liquid is exposed to a large air-water interface. The reduced wall friction is expected to cause a higher electro-osmotic mobility. On the other hand, the low charge density of a superhydrophobic surface reduces the electro-osmotic mobility. Due to a lack of experimental data it has not been clear so far whether the reduced wall friction or the reduced charge density dominate the electrokinetic mobilities. To separate the relative contributions of electrophoresis and electro-osmosis, the mobilities of colloids on a negatively charged hydrophilic, a superhydrophobic (Cassie) and a partially hydrophilized superhydrophobic (Cassie composite) coating were measured. To vary the charge density as well as its sign with respect to those of the colloids the partially hydrophilized surfaces were coated with polyelectrolytes. We analyzed the electrokinetic mobilities of negatively charged polystyrene colloids dispersed in aqueous medium on porous hydrophilic and superhydrophobic surfaces by confocal laser scanning electron microscopy. In all cases, the external electric field was parallel to the surface. The total electrokinetic mobilities on the superhydrophobic (Cassie) and negatively charged partially hydrophilized (Cassie composite) surfaces were similar, showing that electro-osmosis is small compared to electrophoresis. The positively charged Cassie composite surfaces tend to ‘trap’ the colloids due to attracting electrostatic interactions and rough morphology, reducing the mobility. Thus, either the charge density of the coatings in the Cassie composite state or its slip length is too low to enhance electro-osmosis.

Electrokinetic In Situ Treatment of Metal-Contaminated Soil

Science.gov (United States)

Quinn, Jacqueline; Clausen, Christian A., III; Geiger, Cherie; Reinhart, Debra

2004-01-01

An electrokinetic technique has been developed as a means of in situ remediation of soils, sludges, and sediments that are contaminated with heavy metals. Examples of common metal contaminants that can be removed by this technique include cadmium, chromium, zinc, lead, mercury, and radionuclides. Some organic contaminants can also be removed by this technique. In the electrokinetic technique, a low-intensity direct current is applied between electrodes that have been implanted in the ground on each side of a contaminated soil mass. The electric current causes electro-osmosis and migration of ions, thereby moving aqueous-phase subsurface contaminants from one electrode to the other. The half reaction at the anode yields H+, thereby generating an acid front that travels from the anode toward the cathode. As this acid front passes through a given location, the local increase in acidity increases the solubility of cations that were previously adsorbed on soil particles. Ions are transported towards one electrode or the other which one depending on their respective electric charges. Upon arrival at the electrodes, the ionic contaminants can be allowed to become deposited on the electrodes or can be extracted to a recovery system. Surfactants and other reagents can be introduced at the electrodes to enhance rates of removal of contaminants. Placements of electrodes and concentrations and rates of pumping of reagents can be adjusted to maximize efficiency. The basic concept of electrokinetic treatment of soil is not new. What is new here are some of the details of application and the utilization of this technique as an alternative to other techniques (e.g., flushing or bioremediation) that are not suitable for treating soils of low hydraulic conductivity. Another novel aspect is the use of this technique as a less expensive alternative to excavation: The cost advantage over excavation is especially large in settings in which contaminated soil lies near and/or under

A new electrokinetic technology for revitalization of oily sludge

Energy Technology Data Exchange (ETDEWEB)

Habibi, S.

2004-07-01

Oily sludge is a mixture of hydrocarbons, water, metals and suspended fine solids. The petroleum industry is faced with the challenge of handling large volumes of such sludge whose properties depend on the nature of the crude oil, the processing capacity, the down-stream capacities and the design of effluent treatment plants. The management of oily sludge is both complicated and costly due to its complex composition. For that reason, this study developed a method to improve the separation of phases to allow for greater reuse of oily sludge. The study focused on the use of electrokinetic phenomena for the remediation of oily sludge. An amphoteric surfactant was used to evaluate the effect of surfactant on the electrokinetic mobilization or organic contaminants in oily sludge. A series of electrokinetic cell tests were conducted with varying electrical potentials for a 32 day period. Electrical parameters were measured on a daily basis and samples were collected at specific time intervals for UV/VIS and FTIR analysis. The study involved a range of electrokinetic processes such as electrocoagulation, electro-coalescence, desorption, electrophoresis and electro-osmosis. Study results were used to evaluate the thermodynamics of the proposed process and new theories on the behaviour of colloidal components of oily sludge were derived. The study indicated that there is an excellent separation of water, hydrocarbon and solid phases. Since the recovered solid phase has a high hydrocarbon content, it can be recycled for other processes. Some of the volatile hydrocarbons that were released during the process can also be captured and burned as a fuel. The separated water had a low concentration of hydrocarbon and could be sent to wastewater treatment plants.

The improvement of Pilot-scale Electrokinetic for Radioactive Soil Decontamination

International Nuclear Information System (INIS)

Park, Hye Min; Kim, Gye Nam; Kim, Wan Suk; Moon, Jai Kwon

2012-01-01

Most nuclear facility sites have been contaminated by leakage of radioactive waste-solution due to corrosion of the waste-solution tanks and connection pipes by their long-term operation, set up around underground nuclear facilities. Therefore it was needed that the method to remediate a large volume of radioactive soil should be developed. Until now the soil washing method has studied to remediate soil contaminated with uranium, cobalt, cesium, and so on. But it has a lower removal efficiency of nuclide from soils and generated a large volume of waste-solution. And its application to the soil composed of fine particle is impossible. So, the electrokinetic method has been studied as a new technology for soil remediation recently. In this study, the original electrokinetic equipment of 50L suitable to soil contamination characteristics of Korean nuclear facility sites was manufactured for the remediation of soil contaminated with uranium. During experiment with the original electrokinetic equipment, many metal oxides were generated and were stuck on the cathod plate. Several methods to reduce the generation quantity of metal oxides in the electrokinetic equipment and to take off metal oxides from the cathod plate were improved. The soil with uranium was remediated with the improved electrokinetic equipment. The required time to remediate a radioactive soil to under a clearance concentration level was yielded through demonstration experiment with the improved electrokinetic equipment for its different radioactivity concentration

The improvement of Pilot-scale Electrokinetic for Radioactive Soil Decontamination

Energy Technology Data Exchange (ETDEWEB)

Park, Hye Min; Kim, Gye Nam; Kim, Wan Suk; Moon, Jai Kwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2012-05-15

Most nuclear facility sites have been contaminated by leakage of radioactive waste-solution due to corrosion of the waste-solution tanks and connection pipes by their long-term operation, set up around underground nuclear facilities. Therefore it was needed that the method to remediate a large volume of radioactive soil should be developed. Until now the soil washing method has studied to remediate soil contaminated with uranium, cobalt, cesium, and so on. But it has a lower removal efficiency of nuclide from soils and generated a large volume of waste-solution. And its application to the soil composed of fine particle is impossible. So, the electrokinetic method has been studied as a new technology for soil remediation recently. In this study, the original electrokinetic equipment of 50L suitable to soil contamination characteristics of Korean nuclear facility sites was manufactured for the remediation of soil contaminated with uranium. During experiment with the original electrokinetic equipment, many metal oxides were generated and were stuck on the cathod plate. Several methods to reduce the generation quantity of metal oxides in the electrokinetic equipment and to take off metal oxides from the cathod plate were improved. The soil with uranium was remediated with the improved electrokinetic equipment. The required time to remediate a radioactive soil to under a clearance concentration level was yielded through demonstration experiment with the improved electrokinetic equipment for its different radioactivity concentration

Movement of pentachlorophenol in unsaturated soil by electrokinetics

Energy Technology Data Exchange (ETDEWEB)

Harbottle, M.; Sills, G. [Dept. of Engineering Science, Oxford (United Kingdom); Jackman, S. [Dept. of Engineering Science, Oxford (United Kingdom)]|[NERC Centre for Ecology and Hydrology, Oxford (United Kingdom); Thompson, I. [NERC Centre for Ecology and Hydrology, Oxford (United Kingdom)

2001-07-01

Electrokinetic experiments have been performed on unsaturated natural soil specimens artificially contaminated with pentachlorophenol. Movement of pentachlorophenol within the soil mass has been demonstrated, but no contaminant was discovered in any effluent fluids. The results indicate that it may be possible to improve the bioavailability of the pollutant to degradative microorganisms using electrokinetics, by moving the chemical and microbes relative to each others. (orig.)

Transport of radioactive ions in soil by electrokinetics

International Nuclear Information System (INIS)

Buehler, M.F.; Surma, J.E.; Virden, J.W.

1994-10-01

An electrokinetic approach is being evaluated for in situ soil remediation at the Hanford Site in Richland, Washington. This approach uses an applied electric field to induce transport of both radioactive and hazardous waste ions in soil. The work discussed in this paper involves the development of a new method to monitor the movement of the radioactive ions within the soil during the electrokinetic process. A closed cell and a gamma counter were used to provide iii situ measurements of 137 Cs and 60 Co movement in Hanford soil. Preliminary results show that for an applied potential of 200 V over approximately 200 hr, 137 Cs and 60 60 were transported a distance of 4 to 5 in. The monitoring technique demonstrated the feasibility of using electrokinetics for soil separation applications

Three-dimensional electrokinetic tweezing: device design, modeling, and control algorithms

International Nuclear Information System (INIS)

Probst, Roland; Shapiro, Benjamin

2011-01-01

We show how to extend electrokinetic tweezing (which can manipulate any visible particles and has more favorable force scaling than optical actuation enabling manipulation of nanoscale objects to nanoscopic precision) from two-dimensional control to the third dimension (3D). A novel and practical multi-layer device is presented that can create both planar and vertical flow and electric field modes. Feedback control algorithms are developed and demonstrated in realistic simulations to show 3D manipulation of one and two particles independently. The design and control results presented here are the essential next step to go from current 2D manipulation capabilities to an experimental demonstration of nano-precise 3D electrokinetic tweezing in a microfluidic system. Doing so requires integration with vision-based nano-precise 3D particle imaging, a capability that has been shown in the literature and which we are now combining with the 3D actuation and control methods demonstrated here. (technical note)

Modeling electrokinetic transport in phenol contaminated soils

Energy Technology Data Exchange (ETDEWEB)

Zorn, R.; Haus, R.; Czurda, K. [Dept. of Applied Geology, Univ. Karlsruhe (Germany)

2001-07-01

Numerical simulations are compared to laboratory experiments of electroremediation in soils contaminated by phenolic pollutants. The developing pH affects the electrokinetic transport behaviour of phenol. It is found that a water chemistry model must be included in an electrokinetic mass transport model to describe the process of electroremediation more accurately, if no buffering system is used at the electrodes. In the case of controlling the pH at the electrode compartments only a simplified chemical reaction model must be included in the numerical code to match the experimental phenolic transport. (orig.)

Recovery of zinc in phosphor wastes via electrokinetic treatments

International Nuclear Information System (INIS)

Yu, M.Y.; Wang, H. Paul; Chen, C.Y.; Hsiung, T.-L.; Wei, Yu-Ling; Tai, H.-S.; Chiang, K.-C.

2007-01-01

Speciation of zinc in phosphor wastes during electrokinetic treatments has been studied by in situ X-ray absorption near edge structure (XANES) spectroscopy in the present work. The least-square fits of the in situ XANES spectra show that the major zinc species in the phosphor waste are ZnS (77%), ZnO (10%), and Zn(OH) 2 (13%). During the electrokinetic treatment for 90 min, 25% of ZnS and 4% of ZnO are dissolved. About 42% of zinc is enriched on the cathode under the electric field (5 V/cm). Prolonging the electrokinetic treatment time to 4 h under the electric field of 5 V/cm, at least 80% of zinc in the phosphor waste can be recovered

Electrokinetic remediation of contaminated soils: An update

International Nuclear Information System (INIS)

Lindgren, E.R.; Kozak, M.W.; Mattson, E.D.

1992-01-01

Electrokinetic remediation of chromium contaminated soil has been demonstrated for unsaturated 50-100 mesh sand with 10% moisture by weight. The initial region of sand contaminated with 100 ppm w chromate ions was completely cleansed of contamination. After 22 hours of treatment, chromate was found near the anode and apparently migrated at a rate of at least 0.40 cm/hr with a pore water current density of 2.26mA/cm 2 . An analogous run was made using the same sand and FD and C Red No. 40 as the contaminant at a molar concentration equivalent to the 100 ppm w Cr run. The position of the migrating dye was monitored photographically. After similar treatment conditions, the visual dye concentration profile exhibited characteristics similar to the chromate. The migration rate of the dye was slower than the chromate but the qualitative similarity of behavior in an electric field suggests the dye is an analog for chromate ions. The slower migration rate of the dye is not unexpected because the dye molecule is larger than chromate. The use of dye as an analog for chromate greatly accelerates the experimentation process in unsaturated soil because destructive sampling is not required to monitor the contaminant location. Experiments were also conducted to determine the effect of soil heterogeneities on the electrokinetic processes. Unsaturated sands in size fractions of 50-100 mesh (medium) and 100-200 mesh (fine) were studied both individually and in layers. The dye migration rate was accelerated in the tine sand and slowed in the medium sand of the layered experiment when compared with the corresponding individual experiments. This discrepancy was explained by estimating the current density in each layer which was proportionally higher in the fine layer and lower in the medium layer. These preliminary experiments illustrate the significant dependence of electromigration rates on current density. (author)

The optimisation of electrokinetic remediation for heavy metals and radioactivity contamination on Holyrood-Lunas soil (acrisol species) in Sri Gading Industrial Area, Batu Pahat, Johor, Malaysia

International Nuclear Information System (INIS)

Mohamed Johar, S.; Embong, Z.

2015-01-01

The optimisation of electrokinetic remediation of an alluvial soil, locally named as Holyrood-Lunas from Sri Gading Industrial Area, Batu Pahat, Johor, Malaysia, had been conducted in this research. This particular soil was chosen due to its relatively high level of background radiation in a range between 139.2 and 539.4 nGy h -1 . As the background radiation is correlated to the amount of parent nuclides, 238 U and 232 Th, hence, a remediation technique, such as electrokinetic, is very useful in reducing these particular concentrations of heavy metal and radionuclides in soils. Several series of electrokinetics experiments were performed in laboratory scale in order to study the influence of certain electrokinetic parameters in soil. The concentration before (pre-electrokinetic) and after the experiment (post-electrokinetic) was determined via X-ray fluorescence (XRF) analysis technique. The best electrokinetic parameter that contributed to the highest achievable concentration removal of heavy metals and radionuclides on each experimental series was incorporated into a final electrokinetic experiment. Here, High Pure Germanium (HPGe) was used for radioactivity elemental analysis. The XRF results suggested that the most optimised electrokinetic parameters for Cr, Ni, Zn, As, Pb, Th and U were 3.0 h, 90 volts, 22.0 cm, plate-shaped electrode by 8 x 8 cm and in 1-D configuration order whereas the selected optimised electrokinetic parameters gave very low reduction of 238 U and 232 Th at 0.23 ± 2.64 and 2.74 ± 23.78 ppm, respectively. (authors)

Electrokinetics of diffuse soft interfaces. 2. Analysis based on the nonlinear Poisson-Boltzmann equation

NARCIS (Netherlands)

Duval, J.F.L.

2005-01-01

In a previous study (Langmuir 2004, 20, 10324), the electrokinetic properties of diffuse soft layers were theoretically investigated within the framework of the Debye-H¿ckel approximation valid in the limit of sufficiently low values for the Donnan potential. In the current paper, the

Analysis of antiepileptic drugs in biological fluids by means of electrokinetic chromatography.

Science.gov (United States)

Pucci, Vincenzo; Raggi, Maria Augusta

2005-02-01

An overview of the electrokinetic chromatographic methods for the analysis of antiepileptic drug levels in biological samples is presented. In particular, micellar electrokinetic capillary chromatography is a very suitable method for the determination of these drugs, because it allows a rapid, selective, and accurate analysis. In addition to the electrokinetic chromatographic studies on the determination of antiepileptic drugs, some information regarding sample pretreatment will also be reported: this is a critical step when the analysis of biological fluids is concerned. The electrokinetic chromatographic methods for the determination of recent antiepileptic drugs (e.g., lamotrigine, levetiracetam) and classical anticonvulsants (e.g., carbamazepine, phenytoin, ethosuximide, valproic acid) will be discussed in depth, and their pharmacological profiles will be briefly described as well.

Application of bioassays to evaluate a copper contaminated soil before and after a pilot-scale electrokinetic remediation

Energy Technology Data Exchange (ETDEWEB)

Wang Quanying [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Zhou Dongmei [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China)], E-mail: dmzhou@issas.ac.cn; Cang Long [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Sun Tianran [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China)

2009-02-15

Remediation programmes are considered to be complete when human risk-based criteria are met. However, these targets are often unsatisfied with the ecological parameters that may be important with regard to future soil use. Five soil subsamples, collecting along a pilot-scale soil column after electrokinetic treatment, were studied, from which about 42.0%-93.3% soil Cu had been successfully removed. A series of biological assays including soil microbial biomass carbon, basal soil respiration, soil urease activity, earthworm assays, and seed assays were used to evaluate their ecological risks. The results showed that the bioassay data from the treatment variants did not supposedly reflecting the decreased soil Cu concentrations after the electrokinetic treatment, but were highly correlated with some soil physicochemical characteristics. It suggests that bioassays are necessary to assess the ecotoxicity of soil after electrokinetic treatment. - There has been a motivation towards using biological indicators for risk assessment of contaminated soil after electrokinetic remediation.

Application of bioassays to evaluate a copper contaminated soil before and after a pilot-scale electrokinetic remediation

International Nuclear Information System (INIS)

Wang Quanying; Zhou Dongmei; Cang Long; Sun Tianran

2009-01-01

Remediation programmes are considered to be complete when human risk-based criteria are met. However, these targets are often unsatisfied with the ecological parameters that may be important with regard to future soil use. Five soil subsamples, collecting along a pilot-scale soil column after electrokinetic treatment, were studied, from which about 42.0%-93.3% soil Cu had been successfully removed. A series of biological assays including soil microbial biomass carbon, basal soil respiration, soil urease activity, earthworm assays, and seed assays were used to evaluate their ecological risks. The results showed that the bioassay data from the treatment variants did not supposedly reflecting the decreased soil Cu concentrations after the electrokinetic treatment, but were highly correlated with some soil physicochemical characteristics. It suggests that bioassays are necessary to assess the ecotoxicity of soil after electrokinetic treatment. - There has been a motivation towards using biological indicators for risk assessment of contaminated soil after electrokinetic remediation

Effect of alternating bioremediation and electrokinetics on the remediation of n-hexadecane-contaminated soil

Science.gov (United States)

Wang, Sa; Guo, Shuhai; Li, Fengmei; Yang, Xuelian; Teng, Fei; Wang, Jianing

2016-04-01

This study demonstrated the highly efficient degradation of n-hexadecane in soil, realized by alternating bioremediation and electrokinetic technologies. Using an alternating technology instead of simultaneous application prevented competition between the processes that would lower their efficiency. For the consumption of the soil dissolved organic matter (DOM) necessary for bioremediation by electrokinetics, bioremediation was performed first. Because of the utilization and loss of the DOM and water-soluble ions by the microbial and electrokinetic processes, respectively, both of them were supplemented to provide a basic carbon resource, maintain a high electrical conductivity and produce a uniform distribution of ions. The moisture and bacteria were also supplemented. The optimal DOM supplement (20.5 mg·kg-1 glucose; 80-90% of the total natural DOM content in the soil) was calculated to avoid competitive effects (between the DOM and n-hexadecane) and to prevent nutritional deficiency. The replenishment of the water-soluble ions maintained their content equal to their initial concentrations. The degradation rate of n-hexadecane was only 167.0 mg·kg-1·d-1 (1.9%, w/w) for the first 9 days in the treatments with bioremediation or electrokinetics alone, but this rate was realized throughout the whole process when the two technologies were alternated, with a degradation of 78.5% ± 2.0% for the n-hexadecane after 45 days of treatment.

Electrokinetic remediation of fluorine-contaminated soil and its impact on soil fertility.

Science.gov (United States)

Zhou, Ming; Wang, Hui; Zhu, Shufa; Liu, Yana; Xu, Jingming

2015-11-01

Compared to soil pollution by heavy metals and organic pollutants, soil pollution by fluorides is usually ignored in China. Actually, fluorine-contaminated soil has an unfavorable influence on human, animals, plants, and surrounding environment. This study reports on electrokinetic remediation of fluorine-contaminated soil and the effects of this remediation technology on soil fertility. Experimental results showed that electrokinetic remediation using NaOH as the anolyte was a considerable choice to eliminate fluorine in contaminated soils. Under the experimental conditions, the removal efficiency of fluorine by the electrokinetic remediation method was 70.35%. However, the electrokinetic remediation had a significant impact on the distribution and concentrations of soil native compounds. After the electrokinetic experiment, in the treated soil, the average value of available nitrogen was raised from 69.53 to 74.23 mg/kg, the average value of available phosphorus and potassium were reduced from 20.05 to 10.39 mg/kg and from 61.31 to 51.58 mg/kg, respectively. Meanwhile, the contents of soil available nitrogen and phosphorus in the anode regions were higher than those in the cathode regions, but the distribution of soil available potassium was just the opposite. In soil organic matter, there was no significant change. These experiment results suggested that some steps should be taken to offset the impacts, after electrokinetic treatment.

Hybrid electrokinetics for separation, mixing, and concentration of colloidal particles

International Nuclear Information System (INIS)

Sin, Mandy L Y; Shimabukuro, Yusuke; Wong, Pak Kin

2009-01-01

The advent of nanotechnology has facilitated the preparation of colloidal particles with adjustable sizes and the control of their size-dependent properties. Physical manipulation, such as separation, mixing, and concentration, of these colloidal particles represents an essential step for fully utilizing their potential in a wide spectrum of nanotechnology applications. In this study, we investigate hybrid electrokinetics, the combination of dielectrophoresis and electrohydrodynamics, for active manipulation of colloidal particles ranging from nanometers to micrometers in size. A concentric electrode configuration, which is optimized for generating electrohydrodynamic flow, has been designed to elucidate the effectiveness of hybrid electrokinetics and define the operating regimes for different microfluidic operations. The results indicate that the relative importance of electrohydrodynamics increases with decreasing particle size as predicted by a scaling analysis and that electrohydrodynamics is pivotal for manipulating nanoscale particles. Using the concentric electrodes, we demonstrate separation, mixing, and concentration of colloidal particles by adjusting the relative strengths of different electrokinetic phenomena. The effectiveness of hybrid electrokinetics indicates its potential to serve as a generic technique for active manipulation of colloidal particles in various nanotechnology applications.

The optimisation of electrokinetic remediation for heavy metals and radioactivity contamination on Holyrood-Lunas soil (acrisol species) in Sri Gading Industrial Area, Batu Pahat, Johor, Malaysia.

Science.gov (United States)

Mohamed Johar, S; Embong, Z

2015-11-01

The optimisation of electrokinetic remediation of an alluvial soil, locally named as Holyrood-Lunas from Sri Gading Industrial Area, Batu Pahat, Johor, Malaysia, had been conducted in this research. This particular soil was chosen due to its relatively high level of background radiation in a range between 139.2 and 539.4 nGy h(-1). As the background radiation is correlated to the amount of parent nuclides, (238)U and (232)Th, hence, a remediation technique, such as electrokinetic, is very useful in reducing these particular concentrations of heavy metal and radionuclides in soils. Several series of electrokinetics experiments were performed in laboratory scale in order to study the influence of certain electrokinetic parameters in soil. The concentration before (pre-electrokinetic) and after the experiment (post-electrokinetic) was determined via X-ray fluorescence (XRF) analysis technique. The best electrokinetic parameter that contributed to the highest achievable concentration removal of heavy metals and radionuclides on each experimental series was incorporated into a final electrokinetic experiment. Here, High Pure Germanium (HPGe) was used for radioactivity elemental analysis. The XRF results suggested that the most optimised electrokinetic parameters for Cr, Ni, Zn, As, Pb, Th and U were 3.0 h, 90 volts, 22.0 cm, plate-shaped electrode by 8 × 8 cm and in 1-D configuration order whereas the selected optimised electrokinetic parameters gave very low reduction of (238)U and (232)Th at 0.23 ± 2.64 and 2.74 ± 23.78 ppm, respectively. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Capillary electrokinetic separation techniques for profiling of drugs and related products

NARCIS (Netherlands)

Hilhorst, M.J; Somsen, G.W; de Jong, G.J.

Capillary electrokinetic separation techniques offer high efficiency and peak capacity, and can be very useful for the analysis of samples containing a large variety of (unknown) compounds. Such samples are frequently met in impurity profiling of drugs (detection of potential impurities in a

Fate of zinc in an electroplating sludge during electrokinetic treatments.

Science.gov (United States)

Liu, Shou-Heng; Wang, H Paul

2008-08-01

Chemical structure of zinc in the electrokinetic treatments of an electroplating sludge has been studied by in situ extended X-ray absorption fine structural (EXAFS) and X-ray absorption near edge structural (XANES) spectroscopies in the present work. The least-square fitted XANES spectra indicate that the main zinc compounds in the sludge were ZnCO(3) (75%), ZnOSiO(2) (17%) and Zn(OH)(2) (7%). Zinc in the sludge possessed a Zn-O bond distance of 2.07 A with a coordination number (CN) of 5. In the second shells, the bond distance of Zn-(O)-Si was 3.05 A (CN=2). An increase of Zn-(O)-Si (0.05 A) with a decrease of its CN (from 5 to <1) was found in the early stage of the electrokinetic treatment. Prolong the electrokinetic treatment time to 180 min, about 34% of Zn(II) was dissolved into the aqueous phase and about 68% of Zn(II) in the sludge (or 23% of total zinc) was migrated to the cathode under the electric field (5 V cm(-1)). The dissolution and electromigration rates of Zn(II) in the sludge were 1.0 and 0.6 mmol h(-1)g(-1) sludge, respectively during the electrokinetic treatment. This work also exemplifies the utilization of in situ EXAFS and XANES for revealing speciation and possible reaction pathways during the course of zinc recycling from the sludge by electrokinetic treatments.

Electrokinetic decontamination of concrete

International Nuclear Information System (INIS)

Lomasney, H.L.; SenGupta, A.K.; Yachmenev, V.

1996-01-01

ELECTROSORB Electrokinetic Extraction Technology, developed by ISOTRON Corp., offers a cost-effective approach to treating contaminated concrete. Heavy metals/radionuclides trapped in concrete can be extracted using this process if they are chemically solubilized; solubilizers used are citric acid alone and a mixture of citric and nitric acids. A DC electric field is applied across the contaminated concrete to electrokinetically transport the solubilized contaminants from the concrete pores to a collector on the concrete surface. The collector is an extraction pad laid on the surface. The pad provides confinement for a planar electrode and solubilizer solution; it is operated under a vacuum to hold the pad against the concrete surface. Operation requires little attendance, reducing the workers' health hazards. The process incorporates a mechanism for recycling the solubilizer solution. A field demonstration of the process took place in Building 21 of DOE's Mound facility in Miamisburg, OH, over 12 days in June 1996. The thorium species present in this building's concrete floors included ThO 2 and thorium oxalate. The nitric acid was found to facilitate Th extraction

Impact of electrokinetic remediation on microbial communities within PCP contaminated soil

International Nuclear Information System (INIS)

Lear, G.; Harbottle, M.J.; Sills, G.; Knowles, C.J.; Semple, K.T.; Thompson, I.P.

2007-01-01

Electrokinetic techniques have been used to stimulate the removal of organic pollutants within soil, by directing contaminant migration to where remediation may be more easily achieved. The effect of this and other physical remediation techniques on the health of soil microbial communities has been poorly studied and indeed, largely ignored. This study reports the impact on soil microbial communities during the application of an electric field within ex situ laboratory soil microcosms contaminated with pentachlorophenol (PCP; 100 mg kg -1 oven dry soil). Electrokinetics reduced counts of culturable bacteria and fungi, soil microbial respiration and carbon substrate utilisation, especially close to the acidic anode where PCP accumulated (36 d), perhaps exacerbated by the greater toxicity of PCP at lower soil pH. There is little doubt that a better awareness of the interactions between soil electrokinetic processes and microbial communities is key to improving the efficacy and sustainability of this remediation strategy. - Electrokinetics negatively impacted soil

Electrokinetically controlled fluid injection into unicellular microalgae.

Science.gov (United States)

Zhou, Xuewen; Zhang, Xixi; Boualavong, Jonathan; Durney, Andrew R; Wang, Tonghui; Kirschner, Scott; Wentz, Michaela; Mukaibo, Hitomi

2017-10-01

Electrokinetically controlled microinjection is reported as an effective transport mechanism for microinjection into the wild-type strain of the widely studied model microalga Chlamydomonas reinhardtii. A microinjection system using glass capillary pipettes was developed to capture and impale the motile cells. To apply an electric field and induce electrokinetic flow (e.g., electrophoresis and electroosmosis), an electrode was inserted directly into the solution inside the impaling injection pipette and another electrode was inserted into the external cell media. The viability of the impaled cells was confirmed for more than an hour under 0.01 V using the fluorescein diacetate/propidium iodide dual fluorescent dye based assay. The viability was also found to increase almost logarithmically with decreasing voltage and to depend strongly on the solution within the injection pipette. Successful electrokinetic microinjection into cells was confirmed by both an increase in cell volume under an applied voltage and electric field dependent delivery of fluorescent fluorescein molecules into an impaled cell. Our study offers novel opportunities for quantitative delivery of biomolecules into microalgae and advancing the research and development of these organisms as biosynthetic factories. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Data on flow cell optimization for membrane-based electrokinetic energy conversion

Directory of Open Access Journals (Sweden)

David Nicolas Østedgaard-Munck

2017-12-01

Full Text Available This article elaborates on the design and optimization of a specialized flow cell for the measurement of direct conversion of pressure into electrical energy (Electrokinetic Energy Conversion, EKEC which has been presented in Østedgaard-Munck et al. (2017 [1]. Two main flow cell parameters have been monitored and optimized: A the hydraulic pressure profile on each side of the membrane introduced by pumps recirculating the electrolyte solution through the flow fields and B the electrical resistance between the current collectors across the combined flow cell. The latter parameter has been measured using four-point Electrochemical Impedance spectroscopy (EIS for different flow rates and concentrations. The total cell resistance consists of contributions from different components: the membrane (Rmem, anode charge transfer (RA, cathode charge transfer (RC, and ion diffusion in the porous electrodes (RD.The intrinsic membrane properties of Nafion 117 has been investigated experimentally in LiI/I2 solutions with concentrations ranging between 0.06 and 0.96 M and used to identify the preferred LiI/I2 solution concentration. This was achieved by measuring the solution uptake, internal solution concentration and ion exchange capacity. The membrane properties were further used to calculate the transport coefficients and electrokinetic Figure of merit in terms of the Uniform potential and Space charge models. Special attention has been put on the streaming potential coefficient which is an intrinsic property. Keywords: Electrokinetic energy conversion, Electrochemical flow cell, Conversion efficiency

Electrokinetic mobilisation of toluene and chlorinated ethenes in low permeable soils

Energy Technology Data Exchange (ETDEWEB)

Middeldorp, P.; Sinke, A. [TNO Environment Energy and Process Innovation, Apeldoorn (Netherlands)

2001-07-01

An electrokinetic horizontal soil column setup was developed to study the effect of electric current on the mobilisation and biodegradation of organic pollutants in soil. Toluene and tetrachloroethene (PCE) were injected between the two electrodes in the center of the soil column and a DC current of 1 V/cm was applied. We observed a breakthrough of PCE and toluene at the cathode side after 8 days and 11 days respectively. This short experiment shows the possibility to enhance the mobility of non-ionic organic pollutants through electro-osmosis. (orig.)

Marble protection: An inorganic electrokinetic approach

Energy Technology Data Exchange (ETDEWEB)

Meloni, Paola, E-mail: paola.meloni@dimcm.unica.it [Department of Mechanical, Chemical and Materials Engineering (DIMCM), University of Cagliari, Via Marengo 2, 09123 Cagliari (Italy); Manca, Francesco, E-mail: ing.francesco.manca@gmail.com [Department of Mechanical, Chemical and Materials Engineering (DIMCM), University of Cagliari, Via Marengo 2, 09123 Cagliari (Italy); Carcangiu, Gianfranco, E-mail: gcarcan@unica.it [Istituto di Geologia Ambientale e Geoingegneria (IGAG), CNR, Piazza d’Armi, 09123 Cagliari (Italy)

2013-05-15

The influence of an electric potential difference in an aqueous solution was studied as a method for depositing a calcium oxalate coating over a weathered carbonatic stone. Samples of weathered Carrara white marble were treated at 15 and 50 °C for 5 h in an electrokinetic cell, specifically conceived for this study, containing a solution of ammonium oxalate (4% by weight), and were subsequently characterised by scanning electron microscopy, X-ray diffractometry, thermogravimetric analysis and mercury intrusion porosimetry. The electrokinetic treatment proved to be a cost effective and time saving process, able to produce a thick and homogeneous calcium oxalate coating over the stone surface that improves its chemical and physical resistance in low pH environments, and is able to protect the stone from the by-products of urban pollution.

Marble protection: An inorganic electrokinetic approach

Science.gov (United States)

Meloni, Paola; Manca, Francesco; Carcangiu, Gianfranco

2013-05-01

The influence of an electric potential difference in an aqueous solution was studied as a method for depositing a calcium oxalate coating over a weathered carbonatic stone. Samples of weathered Carrara white marble were treated at 15 and 50 °C for 5 h in an electrokinetic cell, specifically conceived for this study, containing a solution of ammonium oxalate (4% by weight), and were subsequently characterised by scanning electron microscopy, X-ray diffractometry, thermogravimetric analysis and mercury intrusion porosimetry. The electrokinetic treatment proved to be a cost effective and time saving process, able to produce a thick and homogeneous calcium oxalate coating over the stone surface that improves its chemical and physical resistance in low pH environments, and is able to protect the stone from the by-products of urban pollution.

Marble protection: An inorganic electrokinetic approach

International Nuclear Information System (INIS)

Meloni, Paola; Manca, Francesco; Carcangiu, Gianfranco

2013-01-01

The influence of an electric potential difference in an aqueous solution was studied as a method for depositing a calcium oxalate coating over a weathered carbonatic stone. Samples of weathered Carrara white marble were treated at 15 and 50 °C for 5 h in an electrokinetic cell, specifically conceived for this study, containing a solution of ammonium oxalate (4% by weight), and were subsequently characterised by scanning electron microscopy, X-ray diffractometry, thermogravimetric analysis and mercury intrusion porosimetry. The electrokinetic treatment proved to be a cost effective and time saving process, able to produce a thick and homogeneous calcium oxalate coating over the stone surface that improves its chemical and physical resistance in low pH environments, and is able to protect the stone from the by-products of urban pollution.

Relationships between Electrokinetic Index of buccal epithelium and some functional and metabolic parameters at men with chronic pyelonephrite

Directory of Open Access Journals (Sweden)

Iryna G. Kyrylenko

2016-01-01

  Abstracts   Background. Known for a number of parameters of the body, which through regression equations derived can assess biological age. We examined relationships between electrokinetic mobility buccal epithelium cell nuclei, named Electrokinetic Index (EKI, and some functional and metabolic parameters of body. Methods. Under a observations were 23 men by age 24-70 years with chronic pyelonephrite in the phase of remission. We estimated the EKI, state of the vegetative and hormonal regulation as well as metabolism of cholesterol. Results. We confirned closely correlation (r=-0,89 between Metric Age and EKI. Baevskiy’s Adaptation Potential and Stange’s Test together determines EKI on 28%. RMSSD, VLF and Baevskiy’s Stress Index determines EKI on 31%. Plasma Colesterol and Klimov’s Atherogenicity Coefficient determines EKI on 56%. In summary model of multiple regression with stepwise excluding are currently two last parameters as well as Plasma Testosterone and relative Power Spectral VLF HRV, which together determines EKI on 73%: R=0,868; R2=0,754; Adjusted R2=0,730;F(4,4=31,4; χ2(4=58,9; p<10-5. Conclusion. Electrokinetic Index of buccal epithelium really rellects neuro-endocrine regulation and metabolism of Cholesterol.   Keywords: Electrokinetic Index, Biological Age, HRV, Cholesterol, Testosterone, Cortisol, Relationships.

Integrating Electrokinetic and Bioremediation Process for Treating Oil Contaminated Low Permeability Soil

Science.gov (United States)

Ramadan, Bimastyaji Surya; Effendi, Agus Jatnika; Helmy, Qomarudin

2018-02-01

Traditional oil mining activities always ignores environmental regulation which may cause contamination in soil and environment. Crude oil contamination in low-permeability soil complicates recovery process because it requires substantial energy for excavating and crushing the soil. Electrokinetic technology can be used as an alternative technology to treat contaminated soil and improve bioremediation process (biostimulation) through transfer of ions and nutrient that support microorganism growth. This study was conducted using a combination of electrokinetic and bioremediation processes. Result shows that the application of electrokinetic and bioremediation in low permeability soils can provide hydrocarbon removal efficiency up to 46,3% in 7 days operation. The highest amount of microorganism can be found in 3-days operation, which is 2x108 CFU/ml using surfactant as flushing fluid for solubilizing hydrocarbon molecules. Enhancing bioremediation using electrokinetic process is very potential to recover oil contaminated low permeability soil in the future.

Modelling of Electrokinetic Processes in Civil and Environmental Engineering Applications

DEFF Research Database (Denmark)

Paz-Garcia, Juan Manuel; Johannesson, Björn; Ottosen, Lisbeth M.

2011-01-01

conditions are assumed between the aqueous species and the solid matrix for a set of feasible chemical equilibrium reactions defined for each specific application. A module for re-establishing the chemical equilibrium has been developed and included in the system for this purpose. Changes in the porosity......A mathematical model for the electrokinetic phenomena is described. Numerical simulations of different applications of electrokinetic techniques to the fields of civil and environmental engineering are included, showing the versatility and consistency of the model. The electrokinetics phenomena......-Nernst-Planck system of equations, accounting for ionic migration, chemical diffusion and advection is used for modeling the transport process. The advection term contributor is studied by including in the system the water transport through the porous media, mainly due to electroosmosis. The pore solution filling...

Basic principles of electrolyte chemistry for microfluidic electrokinetics. Part II: Coupling between ion mobility, electrolysis, and acid-base equilibria.

Science.gov (United States)

Persat, Alexandre; Suss, Matthew E; Santiago, Juan G

2009-09-07

We present elements of electrolyte dynamics and electrochemistry relevant to microfluidic electrokinetics experiments. In Part I of this two-paper series, we presented a review and introduction to the fundamentals of acid-base chemistry. Here, we first summarize the coupling between acid-base equilibrium chemistry and electrophoretic mobilities of electrolytes, at both infinite and finite dilution. We then discuss the effects of electrode reactions on microfluidic electrokinetic experiments and derive a model for pH changes in microchip reservoirs during typical direct-current electrokinetic experiments. We present a model for the potential drop in typical microchip electrophoresis device. The latter includes finite element simulation to estimate the relative effects of channel and reservoir dimensions. Finally, we summarize effects of electrode and electrolyte characteristics on potential drop in microfluidic devices. As a whole, the discussions highlight the importance of the coupling between electromigration and electrophoresis, acid-base equilibria, and electrochemical reactions.

Removal of Uranium in Soil Using Large-scale Electrokinetic Decontamination Equipment

Energy Technology Data Exchange (ETDEWEB)

Kim, Gye Nam; Kim, Il gook; Jeong, Jung Whan; Kim, Seung Soo; Choi, Jong Won [KAERI, Daejeon (Korea, Republic of)

2016-05-15

A method to remediate a large volume of radioactive soil should be developed. Until now the soil washing method has been studied to remediate soil contaminated with uranium, cobalt, cesium, and so on. However, it has a lower removal efficiency of nuclide from soils and generated a large volume of waste-solution. In addition, its application to the soil composed of fine particle is impossible. Thus, the electrokinetic method has been studied as a new technology for soil remediation recently. In this study, for a reduction of the waste electrolyte volume, the reuse period of waste electrolyte in the electrokinetic decontamination experiment through several experiments with the manufactured 1.2 ton electrokinetic decontamination equipment. In addition, the time required to reach below the clearance concentration level for self- disposal was estimated through several experiments using the manufactured electrokinetic decontamination equipment. When the initial uranium concentrations in the soils were 7.0-20.0 Bq/g, the times required to reach below the clearance concentration level for self-disposal were 25-40 days with the waste and reclaimed electrolytes.

Removal of PAH using electrokinetic transport of biosurfactants in clayey soil

Energy Technology Data Exchange (ETDEWEB)

Maria, E.; Lin, J. [Dept. of Building Civil and Environmental Engineering, Concordia Univ., Montreal (Canada)

2001-07-01

The electrokinetic introduction of non-toxic, biodegradable surfactants (produced ex-situ) to remediate PAH-contaminated soil was investigated. The lab tests demonstrated the possibility of removal of organic contaminants from clayey soil without hazardous impact to the environment. The rhamnolipids (biosurfactants), produced by Pseudomonas aeruginosa to increase the solubility of PAHs into the aqueous phase, were used in the enhancement of electrokinetic remediation. This study determined the potential on-site production of biosurfactants that was directly introduced to soil by means of electrokinetics. The average removal of phenanthrene achieved 74% in the presence of biosurfactants above CMC. The remaining compounds are left for biodegradation. These results contribute to the development of a new remediation technology - bioelectrokinetics. (orig.)

Electrokinetic Hydrogen Generation from Liquid WaterMicrojets

Energy Technology Data Exchange (ETDEWEB)

Duffin, Andrew M.; Saykally, Richard J.

2007-05-31

We describe a method for generating molecular hydrogen directly from the charge separation effected via rapid flow of liquid water through a metal orifice, wherein the input energy is the hydrostatic pressure times the volume flow rate. Both electrokinetic currents and hydrogen production rates are shown to follow simple equations derived from the overlap of the fluid velocity gradient and the anisotropic charge distribution resulting from selective adsorption of hydroxide ions to the nozzle surface. Pressure-driven fluid flow shears away the charge balancing hydronium ions from the diffuse double layer and carries them out of the aperture. Downstream neutralization of the excess protons at a grounded target electrode produces gaseous hydrogen molecules. The hydrogen production efficiency is currently very low (ca. 10-6) for a single cylindrical jet, but can be improved with design changes.

Integrating Electrokinetic and Bioremediation Process for Treating Oil Contaminated Low Permeability Soil

Directory of Open Access Journals (Sweden)

Surya Ramadan Bimastyaji

2018-01-01

Full Text Available Traditional oil mining activities always ignores environmental regulation which may cause contamination in soil and environment. Crude oil contamination in low-permeability soil complicates recovery process because it requires substantial energy for excavating and crushing the soil. Electrokinetic technology can be used as an alternative technology to treat contaminated soil and improve bioremediation process (biostimulation through transfer of ions and nutrient that support microorganism growth. This study was conducted using a combination of electrokinetic and bioremediation processes. Result shows that the application of electrokinetic and bioremediation in low permeability soils can provide hydrocarbon removal efficiency up to 46,3% in 7 days operation. The highest amount of microorganism can be found in 3-days operation, which is 2x108 CFU/ml using surfactant as flushing fluid for solubilizing hydrocarbon molecules. Enhancing bioremediation using electrokinetic process is very potential to recover oil contaminated low permeability soil in the future.

Electrokinetics for removal of low-level radioactivity from soil

Energy Technology Data Exchange (ETDEWEB)

Pamukcu, S. [Lehigh Univ., Bethlehem, PA (United States); Wittle, J.K. [Electro-Petroleum, Inc., Wayne, PA (United States)

1993-03-01

The electrokinetic process is an emerging technology for in situ soil decontamination in which chemical species, both ionic and nonionic, are transported to an electrode site in soil. These products are subsequently removed from the ground via collection systems engineered for each specific application. The work presented here describes part of the effort undertaken to investigate electrokinetically enhanced transport of soil contaminants in synthetic systems. These systems consisted of clay or clay-sand mixtures containing known concentrations of a selected heavy-metal salt solution. These metals included surrogate radionuclides such as Sr, Cs and U, and an anionic species of Cr. Degree of removal of these metals from soil by the electrokinetic treatment process was assessed through the metal concentration profiles generated across the soil between the electrodes. Removals of some metal species up to 99% were achieved at the anode or cathode end of the soil upon 24 to 48 hours of treatment or a maximum of 1 pore volume of water displacement toward the cathode compartment. Transient pH change through the soil had an effect on the metal movement, as evidenced by accumulation of the metals at the discharge ends of the soil specimens. This accumulation was attributed to the precipitation of the metal and increased cation retention capacity of the clay in high pH environment at the cathode end. In general, the reduced mobility and dissociation of the ionic species as they encounter areas of higher ionic concentration in their path of migration resulted in the accumulation of the metals at the discharge ends of the soil specimens.

Field Testing of Rapid Electrokinetic Nanoparticle Treatment for Corrosion Control of Steel in Concrete

Science.gov (United States)

Cardenas, Henry E.; Alexander, Joshua B.; Kupwade-Patil,Kunal; Calle, Luz Marina

2009-01-01

This work field tested the use of electrokinetics for delivery of concrete sealing nanoparticles concurrent with the extraction of chlorides. Several cylinders of concrete were batched and placed in immersion at the Kennedy Space Center Beach Corrosion Test Site. The specimens were batched with steel reinforcement and a 4.5 wt.% (weight percent) content of sodium chloride. Upon arrival at Kennedy Space Center, the specimens were placed in the saltwater immersion pool at the Beach Corrosion Test Site. Following 30 days of saltwater exposure, the specimens were subjected to rapid chloride extraction concurrent with electrokinetic nanoparticle treatment. The treatments were operated at up to eight times the typical current density in order to complete the treatment in 7 days. The findings indicated that the short-term corrosion resistance of the concrete specimens was significantly enhanced as was the strength of the concrete.

Pyrene removal from contaminated soil using electrokinetic process combined with surfactant

Directory of Open Access Journals (Sweden)

Seyed Enayat Hashemi

2015-07-01

Full Text Available Background: Pyrene is one of the stable polycyclic aromatic hydrocarbons that is considered as an important pollutants, because of extensive distribution in the environment and carcinogenic and mutagenic properties. Among the various treatment techniques, electrokinetic method is an environmental- friendly process for organic and mineral pollutants adsorbed to soil with fine pore size the same as clay and low hydraulic conductivity soils. For improving the efficiency of pyrene removal from soil, soulobilization of pyrene from soil could be used by surfactants. Materials and Methods : In this study, clay soil was selected as model because of the specific properties. Combined method using surfactant and electrokinetic was applied for pyrene removal from soil. Experiments were designed using response surface methodology (RSM, and effect of three variables includes surfactant concentration, voltage and surfactant type were evaluated for pyrene removal from contaminated soil. Results: Pyrene removal using anionic surfactants(SDS and nonionic surfactants(TX100 as a solubilizing agents has high removal efficiency. In the optimum condition with 95% confidence coefficient, utilizing mixed surfactants of sodium dodecyl sulfate and triton X-100 with the same volume, induced of 18.54 volt and 6.53 percent surfactant concentration have 94.6% pyrene removal efficiency. Conclusion:: Results of this study shows that electrokinetic process combined with surfactant as solubilizing agent could be applied as an efficient method for treating the pyrene-contaminated soils.

Fabrication of High-Aspect-Ratio 3D Hydrogel Microstructures Using Optically Induced Electrokinetics

Directory of Open Access Journals (Sweden)

Yi Li

2016-04-01

Full Text Available We present a rapid hydrogel polymerization and prototyping microfabrication technique using an optically induced electrokinetics (OEK chip, which is based on a non-UV hydrogel curing principle. Using this technique, micro-scale high-aspect-ratio three-dimensional polymer features with different geometric sizes can be fabricated within 1–10 min by projecting pre-defined visible light image patterns onto the OEK chip. This method eliminates the need for traditional photolithography masks used for patterning and fabricating polymer microstructures and simplifies the fabrication processes. This technique uses cross-link hydrogels, such as poly(ethylene glycol (PEG-diacrylate (PEGDA, as fabrication materials. We demonstrated that hydrogel micropillar arrays rapidly fabricated using this technique can be used as molds to create micron-scale cavities in PDMS (polydimethylsiloxane substrates. Furthermore, hollow, circular tubes with controllable wall thicknesses and high-aspect ratios can also be fabricated. These results show the potential of this technique to become a rapid prototyping technology for producing microfluidic devices. In addition, we show that rapid prototyping of three-dimensional suspended polymer structures is possible without any sacrificial etching process.

Electric double layer and electrokinetic potential of pectic macromolecules in sugar beet

Directory of Open Access Journals (Sweden)

Kuljanin Tatjana A.

2008-01-01

Full Text Available Electrokinetic potential is an important property of colloidal particles and, regarding the fact that it is a well defined and easily measurable property, it is considered to be a permanent characteristic of a particular colloidal system. In fact, it is a measure of electrokinetic charge that surrounds the colloidal particle in a solution and is in direct proportion with the mobility of particles in an electric field. Gouy-Chapman-Stern-Graham's model of electric double layer was adopted and it was proven experimentally that the addition of Cu++ ions to sugar beet pectin caused a reduction in the negative electrokinetic potential proportional to the increase of Cu++ concentration. Higher Cu++ concentrations increased the proportion of cation specific adsorption (Cu++ and H+ with regard to electrostatic Coulombic forces. Consequently, there is a shift in the shear plane between the fixed and diffuse layers directed towards the diffuse layer, i.e. towards its compression and decrease in the electrokinetic potential or even charge inversion of pectin macromolecules.

Citric-acid preacidification enhanced electrokinetic remediation for removal of chromium from chromium-residue-contaminated soil.

Science.gov (United States)

Meng, Fansheng; Xue, Hao; Wang, Yeyao; Zheng, Binghui; Wang, Juling

2018-02-01

Electrokinetic experiments were conducted on chromium-residue-contaminated soils collected from a chemical plant in China. Acidification-electrokinetic remediation technology was proposed in order to solve the problem of removing inefficient with ordinary electrokinetic. The results showed that electrokinetic remediation removal efficiency of chromium from chromium-contaminated soil was significantly enhanced with acidizing pretreatment. The total chromium [Cr(T)] and hexavalent chromium [Cr(VI)] removal rate of the group acidized by citric acid (0.9 mol/L) for 5 days was increased from 6.23% and 19.01% in the acid-free experiments to 26.97% and 77.66% in the acidification-treated experiments, respectively. In addition, part of chromium with the state of carbonate-combined will be converted into water-soluble state through acidification to improve the removal efficiency. Within the appropriate concentration range, the higher concentration of acid was, the more chromium was released. So the removal efficiency of chromium depended on the acid concentration. The citric acid is also a kind of complexing agent, which produced complexation with Cr that was released by the electrokinetic treatment and then enhanced the removal efficiency. The major speciation of chromium that was removed from soils by acidification-electrokinetics remediation was acid-soluble speciation, revivification speciation and oxidation speciation, which reduced biological availability of chromium.

Electrokinetic extraction of chromate from unsaturated soils

International Nuclear Information System (INIS)

Mattson, E.D.; Lindgren, E.R.

1993-01-01

Heavy-metal contamination of soil and groundwater is a widespread problem in industrial nations. Remediation by excavation of such sites may not be cost effective or politically acceptable. Electrokinetic remediation is one possible remediation technique for in situ removal of such contaminants from unsaturated soils. Previous papers discussing the work performed by researchers at Sandia National Laboratories (SNL) and Sat-Unsat, Inc. (SUI) (Lindgren et al., 1991, 1992, 1993) focused on the transport of contaminants and dyes by electrokinetics in unsaturated soils. These experiments were conducted with graphite electrodes with no extraction system. As the contaminants migrated through the soil, they increased in concentration at the electrode creating a diffusion flux in the opposite direction. This paper discusses a technique to remove the contaminants from unsaturated soils once they have reached an electrode

Electrokinetic extraction of chromate from unsaturated soils

Energy Technology Data Exchange (ETDEWEB)

Mattson, E.D. [SAT-UNSAT, Inc., Albuquerque, NM (United States); Lindgren, E.R. [Sandia National Labs., Albuquerque, NM (United States)

1993-11-01

Heavy-metal contamination of soil and groundwater is a widespread problem in industrial nations. Remediation by excavation of such sites may not be cost effective or politically acceptable. Electrokinetic remediation is one possible remediation technique for in situ removal of such contaminants from unsaturated soils. Previous papers discussing the work performed by researchers at Sandia National Laboratories (SNL) and Sat-Unsat, Inc. (SUI) (Lindgren et al., 1991, 1992, 1993) focused on the transport of contaminants and dyes by electrokinetics in unsaturated soils. These experiments were conducted with graphite electrodes with no extraction system. As the contaminants migrated through the soil, they increased in concentration at the electrode creating a diffusion flux in the opposite direction. This paper discusses a technique to remove the contaminants from unsaturated soils once they have reached an electrode.

[Optimization of electrode configuration in soil electrokinetic remediation].

Science.gov (United States)

Liu, Fang; Fu, Rong-Bing; Xu, Zhen

2015-02-01

Electric field distributions of several different electrode configurations in non-uniform electric field were simulated using MATLAB software, and the electrokinetic remediation device was constructed according to the best electrode configuration. The changes of soil pH and heavy metal residues in different parts of the device during the electrokinetic remediation were also studied. The results showed that, in terms of the effectiveness of the electric field strength, the square (1-D-1) and hexagonal (2-D-3) were the optimal electrode configurations for one-dimensional and two-dimensional respectively and the changes of soil pH, the removal of heavy metals and the distribution of electric field were closely related to one another. An acidic migration band, which could prevent premature precipitation of heavy metals to a certain extent and promote electrokinetic removal of heavy metals, was formed gradually along with the remediation in the whole hexagon device when the cathodic pH was controlled during the remediation of the four cationic metallic ions, Cd2+, Ni2+, Pb2+ and Cu2+. After 480-hour remediation, the total removals of Cd, Ni, Pb and Cu were 86.6%, 86.2%, 67.7% and 73.0%, respectively. Remediation duration and replacement frequency of the electrodes could be adjusted according to the repair target.

Enhanced electrokinetic remediation of lead-contaminated soil by complexing agents and approaching anodes.

Science.gov (United States)

Zhang, Tao; Zou, Hua; Ji, Minhui; Li, Xiaolin; Li, Liqiao; Tang, Tang

2014-02-01

Optimizing process parameters that affect the remediation time and power consumption can improve the treatment efficiency of the electrokinetic remediation as well as determine the cost of a remediation action. Lab-scale electrokinetic remediation of Pb-contaminated soils was investigated for the effect of complexant ethylenediaminetetraacetic acid (EDTA) and acetic acid and approaching anode on the removal efficiency of Pb. When EDTA was added to the catholyte, EDTA dissolved insoluble Pb in soils to form soluble Pb-EDTA complexes, increasing Pb mobility and accordingly removal efficiency. The removal efficiency was enhanced from 47.8 to 61.5 % when the EDTA concentration was increased from 0.1 to 0.2 M, showing that EDTA played an important role in remediation. And the migration rate of Pb was increased to 72.3 % when both EDTA and acetic acid were used in the catholyte. The "approaching anode electrokinetic remediation" process in the presence of both EDTA and acetic acid had a higher Pb-removal efficiency with an average efficiency of 83.8 %. The efficiency of electrokinetic remediation was closely related to Pb speciation. Exchangeable and carbonate-bounded Pb were likely the forms which could be removed. All results indicate that the approaching anode method in the presence of EDTA and acetic acid is an advisable choice for electrokinetic remediation of Pb-contaminated soil.

Experimental study and mathematical model on remediation of Cd spiked kaolinite by electrokinetics

International Nuclear Information System (INIS)

Mascia, Michele; Palmas, Simonetta; Polcaro, Anna Maria; Vacca, Annalisa; Muntoni, Aldo

2007-01-01

An experimental study on electrokinetic removal of cadmium from kaolinitic clays is presented in this work, which is aimed to investigate the effect of surface reactions on the electrokinetic process. Enhanced electrokinetic tests were performed in which the pH of the compartments was controlled. Cadmium spiked kaolin was adopted in the experimental runs. On the basis of the experimental results, a numerical model was formulated to simulate the cadmium (Cd) transport under an electric field by combining a one-dimensional diffusion-advection model with a geochemical model: the combined model describes the contaminant transport driven by chemical and electrical gradients, as well as the effect of the surface reactions. The geochemical model utilized parameters derived from the literature, and it was validated by experimental data obtained by sorption and titration experiments. Electrokinetic tests were utilized to validate the results of the proposed model. A good prediction of the behaviour of the soil/cadmium ions system under electrical field was obtained: the differences between experimental and model predicted profiles for the species considered were less than 5% in all the examined conditions

Electrokinetic treatment of an agricultural soil contaminated with heavy metals.

Science.gov (United States)

Figueroa, Arylein; Cameselle, Claudio; Gouveia, Susana; Hansen, Henrik K

2016-07-28

The high organic matter content in agricultural soils tends to complex and retain contaminants such as heavy metals. Electrokinetic remediation was tested in an agricultural soil contaminated with Co(+2), Zn(+2), Cd(+2), Cu(+2), Cr(VI), Pb(+2) and Hg(+2). The unenhanced electrokinetic treatment was not able to remove heavy metals from the soil due to the formation of precipitates in the alkaline environment in the soil section close to the cathode. Moreover, the interaction between metals and organic matter probably limited metal transportation under the effect of the electric field. Citric acid and ethylenediaminetetraacetic acid (EDTA) were used in the catholyte as complexing agents in order to enhance the extractability and removal of heavy metals from soil. These complexing agents formed negatively charged complexes that migrated towards the anode. The acid front electrogenerated at the anode favored the dissolution of heavy metals that were transported towards the cathode. The combined effect of the soil pH and the complexing agents resulted in the accumulation of heavy metals in the center of the soil specimen.

Electrokinetic migration studies on removal of chromium and uranyl ions from 904-A trench soil

International Nuclear Information System (INIS)

Bibler, J.P.; Meaker, T.F.; O'Steen, A.B.

1992-01-01

This report describes a laboratory-scale study, in which electrokinetic migration technology was used to remove chromium and uranium, as well as other ions, from soil taken from a bore hole adjacent to the 904-A trench at the Savannah River Technology Center. Imposition of an electric current on humid (not saturated) soil successfully caused cations to migrate through the pore water of the soil to the cathode, where they were captured in an ISOLOCKTm polymer matrix and in a cation exchange resin incorporated in the polymer. Chemicals circulated through the anode/polymer and cathode/polymer were able to control pH excursions in the electrokinetic-cells by reacting with the H + and OH - generated at the anode and cathode, respectively. The study indicates that ions adsorbed on the surface of the soil as well as those in the pores of soil particles can be caused to migrate through the soil to an appropriate electrode. After 10 days of operation at 20--25 V and 2 mA, approximately 65% of the chromium was removed from two 3.5 kg soil samples. A 57% removal of uranium was achieved. The study shows that electrokinetic migration, using the ISOLOCK trademark polymer will be effective as an in situ treatment method for the removal of metal ion contaminants in soil adjacent to the 904-A trench

Principles of Micellar Electrokinetic Capillary Chromatography Applied in Pharmaceutical Analysis

Directory of Open Access Journals (Sweden)

Árpád Gyéresi

2013-02-01

Full Text Available Since its introduction capillary electrophoresis has shown great potential in areas where electrophoretic techniques have rarely been used before, including here the analysis of pharmaceutical substances. The large majority of pharmaceutical substances are neutral from electrophoretic point of view, consequently separations by the classic capillary zone electrophoresis; where separation is based on the differences between the own electrophoretic mobilities of the analytes; are hard to achieve. Micellar electrokinetic capillary chromatography, a hybrid method that combines chromatographic and electrophoretic separation principles, extends the applicability of capillary electrophoretic methods to neutral analytes. In micellar electrokinetic capillary chromatography, surfactants are added to the buffer solution in concentration above their critical micellar concentrations, consequently micelles are formed; micelles that undergo electrophoretic migration like any other charged particle. The separation is based on the differential partitioning of an analyte between the two-phase system: the mobile aqueous phase and micellar pseudostationary phase. The present paper aims to summarize the basic aspects regarding separation principles and practical applications of micellar electrokinetic capillary chromatography, with particular attention to those relevant in pharmaceutical analysis.

Electrokinetic label-free screening chip: a marriage of multiplexing and high throughput analysis using surface plasmon resonance imaging

NARCIS (Netherlands)

Krishnamoorthy, G.; Carlen, Edwin; Bomer, Johan G.; Wijnperle, Daniël; de Boer, Hans L.; van den Berg, Albert; Schasfoort, Richardus B.M.

2010-01-01

We present an electrokinetic label-free biomolecular screening chip (Glass/PDMS) to screen up to 10 samples simultaneously using surface plasmon resonance imaging (iSPR). This approach reduces the duration of an experiment when compared to conventional experimental methods. This new device offers a

2-D model for electrokinetic remediation

Energy Technology Data Exchange (ETDEWEB)

Rodriguez Maroto, J.M.; Garcia Delgado, R.A.; Gomez Lahoz, C.; Garcia Herruzo, F. [Dept. de Ingenieria Quimica, Univ. de Malaga (Spain); Vereda Alonso, C. [Dept. de Ingenieria Quimica, Univ. de Malaga (Spain)]|[Inst. for Geologi and Geoteknik, Danmarks Tekniske Univ., Lyngby (Denmark)

2001-07-01

A simple two-dimensional numerical model is presented in this work. In this case, the model is used to examine the enhanced method of the electrokinetic remediation technique in a 2-D arrangement. Nevertheless the model with minor changes can also be used to study the effect of the electrode configuration in the performance of this technique. (orig.)

Simultaneous removal of organic contaminants and heavy metals from kaolin using an upward electrokinetic soil remediation process

International Nuclear Information System (INIS)

Wang, J.-Y.; Huang, X.-J.; Kao, Jimmy C.M.; Stabnikova, Olena

2007-01-01

Kaolins contaminated with heavy metals, Cu and Pb, and organic compounds, p-xylene and phenanthrene, were treated with an upward electrokinetic soil remediation (UESR) process. The effects of current density, cathode chamber flushing fluid, treatment duration, reactor size, and the type of contaminants under the vertical non-uniform electric field of UESR on the simultaneous removal of the heavy metals and organic contaminants were studied. The removal efficiencies of p-xylene and phenanthrene were higher in the experiments with cells of smaller diameter or larger height, and with distilled water flow in the cathode chamber. The removal efficiency of Cu and Pb were higher in the experiments with smaller diameter or shorter height cells and 0.01 M HNO 3 solution as cathode chamber flow. In spite of different conditions for removal of heavy metals and organics, it is possible to use the upward electrokinetic soil remediation process for their simultaneous removal. Thus, in the experiments with duration of 6 days removal efficiencies of phenanthrene, p-xylene, Cu and Pb were 67%, 93%, 62% and 35%, respectively. The experiment demonstrated the feasibility of simultaneous removal of organic contaminants and heavy metals from kaolin using the upward electrokinetic soil remediation process

Physicochemical effects on uncontaminated kaolinite due to electrokinetic treatment using inert electrodes.

Science.gov (United States)

Liaki, Christina; Rogers, Christopher D F; Boardman, David I

2008-07-01

To determine the consequences of applying electrokinetics to clay soils, in terms of mechanisms acting and resulting effects on the clay, tests were conducted in which an electrical gradient was applied across controlled specimens of English China Clay (ECC) using 'inert' electrodes and a 'Reverse Osmosis' water feed to the electrodes (i.e., to mimic electrokinetic stabilisation without the stabiliser added or electrokinetic remediation without the contaminant being present). The specimens in which electromigration was induced over time periods of 3, 7, 14 and 28 days were subsequently tested for Atterberg Limits, undrained shear strength using a hand shear vane, water content, pH, conductivity and zeta potential. Water flowed through the system from anode to cathode and directly affected the undrained shear strength of the clay. Acid and alkali fronts were created around the anode and cathode, respectively, causing changes in the pH, conductivity and zeta potential of the soil. Variations in zeta potential were linked to flocculation and dispersion of the soil particles, thus raising or depressing the Liquid Limit and Plastic Limit, and influencing the undrained shear strength. Initial weakening around the anode and cathode was replaced by a regain of strength at the anode once acidic conditions had been created, while highly alkaline conditions at the cathode induced a marked improvement in strength. A novel means of indicating strength improvement by chemical means, i.e., free from water content effects, is presented to assist in interpretation of the results.

Feedback-controlled electro-kinetic traps for single-molecule ...

Indian Academy of Sciences (India)

2014-01-11

Jan 11, 2014 ... limited residence time of a given molecule within the detection volume. A common ... information on individual folding pathways, as well as to the internal dynamics between ..... Essentials for building an electro-kinetic trap.

The Physical Behavior of Stabilised Soft Clay by Electrokinetic Stabilisation Technology

Science.gov (United States)

Azhar, A. T. S.; Nordin, N. S.; Azmi, M. A. M.; Embong, Z.; Sunar, N.; Hazreek, Z. A. M.; Aziman, M.

2018-04-01

Electrokinetic Stabilisation (EKS) technology is the combination processes of electroosmosis and chemical grouting. This technique is most effective in silty and clayey soils where the hydraulic conductivity is very low. Stabilising agents will assist the EKS treatment by inducing it into soil under direct current. The movement of stabilising agents into soil is governed by the principle of electrokinetics. The aim of this study is to evaluate the physical behavior of soft soil using the EKS technology as an effective method to strengthen soft clay soils with calcium chloride (CaCl2) as the stabilising agent. Stainless steel plates were used as the electrodes, while 1.0 mol/l of CaCl2 was used as the electrolyte that fed at the anode compartment. Soft marine clay at Universiti Tun Hussein Onn Malaysia was used as the soil sample. The EKS treatment was developed at Research Centre for Soft Soil (RECESS), UTHM with a constant voltage gradient (50 V/m) in 21 days. The result shows that the shear strength of treated soil was increased across the soil sample. The treated soil near the cathode showed the highest value of shear strength (24.5 – 33 kPa) compared with the anode and in the middle of the soil sample.

Testing and evaluation of electrokinetic decontamination of concrete

International Nuclear Information System (INIS)

DePaoli, D.W.; Harris, M.T.; Ally, M.R.

1996-10-01

The goals and objectives of the technical task plan (TTP) are to (1) describe the nature and extent of concrete contamination within the Department of Energy (DOE) complex and emerging and commercial technologies applicable to these problems; (2) to match technologies to the concrete problems and recommend up to four demonstrations; (3) to initiate recommended demonstrations; and (4) to continue investigation and evaluation of the application of electrokinetic decontamination processes to concrete. This document presents findings of experimental and theoretical studies of the electrokinetic decontamination (EK) process and their implications for field demonstrations. This effort is an extension of the work performed under TTP 142005, ''Electroosmotic Concrete Decontamination. The goals of this task were to determine the applicability of EK for treating contaminated concrete and, if warranted, to evaluate EK as a potential technology for demonstration. 62 refs

Electrokinetic Enhanced Permanganate Delivery for Low Permeability Soil Remediation

Science.gov (United States)

Chowdhury, A. I.; Gerhard, J.; Reynolds, D. A.; Sleep, B. E.; O'Carroll, D. M.

2016-12-01

Contaminant mass sequestered in low permeability zones (LPZ) in the subsurface has become a significant concern due to back diffusion of contaminants, leading to contaminant rebound following treatment of the high permeability strata. In-situ remediation technologies such as in-situ chemical oxidation (ISCO) are promising, however, successful delivery of oxidants into silts and clays remains a challenge. Electrokinetics (EK) has been proposed as a technique that can overcome this challenge by delivering oxidants into low permeability soils. This study demonstrates the ability of EK to facilitate permanganate delivery into silt for treatment of trichloroethene (TCE). A two-dimensional sandbox was packed with alternate vertical layers of coarse sand and silt contaminated with high concentrations of aqueous phase TCE. Nine experiments were conducted to compare EK-enhanced in-situ chemical oxidation (EK-ISCO) to ISCO alone or EK alone. Frequent groundwater sampling at multiple locations combined with image analysis provided detailed mapping of TCE, permanganate, and manganese dioxide mass distributions. EK-ISCO successfully delivered the permanganate throughout the silt cross-section while ISCO without EK resulted in permanganate delivery only to the edges of the silt layer. EK-ISCO resulted in a 4.4 order-of-magnitude (OoM) reduction in TCE concentrations in the coarse sand compared to a 3.5 OoM reduction for ISCO alone. This study suggests that electrokinetics coupled with ISCO can achieve enhanced remediation of lower permeability strata, where remediation technologies for successful contaminant mass removal would otherwise be limited.

Electrokinetics of diffuse soft interfaces. 1. Limit of low Donnan potentials.

Science.gov (United States)

Duval, Jérôme F L; van Leeuwen, Herman P

2004-11-09

The current theoretical approaches to electrokinetics of gels or polyelectrolyte layers are based on the assumption that the position of the very interface between the aqueous medium and the gel phase is well defined. Within this assumption, spatial profiles for the volume fraction of polymer segments (phi), the density of fixed charges in the porous layer (rho fix), and the coefficient modeling the friction to hydrodynamic flow (k) follow a step-function. In reality, the "fuzzy" nature of the charged soft layer is intrinsically incompatible with the concept of a sharp interface and therefore necessarily calls for more detailed spatial representations for phi, rho fix, and k. In this paper, the notion of diffuse interface is introduced. For the sake of illustration, linear spatial distributions for phi and rho fix are considered in the interfacial zone between the bulk of the porous charged layer and the bulk electrolyte solution. The corresponding distribution for k is inferred from the Brinkman equation, which for low phi reduces to Stokes' equation. Linear electrostatics, hydrodynamics, and electroosmosis issues are analytically solved within the context of streaming current and streaming potential of charged surface layers in a thin-layer cell. The hydrodynamic analysis clearly demonstrates the physical incorrectness of the concept of a discrete slip plane for diffuse interfaces. For moderate to low electrolyte concentrations and nanoscale spatial transition of phi from zero (bulk electrolyte) to phi o (bulk gel), the electrokinetic properties of the soft layer as predicted by the theory considerably deviate from those calculated on the basis of the discontinuous approximation by Ohshima.

Towards an understanding of induced-charge electrokinetics at large applied voltages in concentrated solutions.

Science.gov (United States)

Bazant, Martin Z; Kilic, Mustafa Sabri; Storey, Brian D; Ajdari, Armand

2009-11-30

The venerable theory of electrokinetic phenomena rests on the hypothesis of a dilute solution of point-like ions in quasi-equilibrium with a weakly charged surface, whose potential relative to the bulk is of order the thermal voltage (kT/e approximately 25 mV at room temperature). In nonlinear electrokinetic phenomena, such as AC or induced-charge electro-osmosis (ACEO, ICEO) and induced-charge electrophoresis (ICEP), several V approximately 100 kT/e are applied to polarizable surfaces in microscopic geometries, and the resulting electric fields and induced surface charges are large enough to violate the assumptions of the classical theory. In this article, we review the experimental and theoretical literatures, highlight discrepancies between theory and experiment, introduce possible modifications of the theory, and analyze their consequences. We argue that, in response to a large applied voltage, the "compact layer" and "shear plane" effectively advance into the liquid, due to the crowding of counterions. Using simple continuum models, we predict two general trends at large voltages: (i) ionic crowding against a blocking surface expands the diffuse double layer and thus decreases its differential capacitance, and (ii) a charge-induced viscosity increase near the surface reduces the electro-osmotic mobility; each trend is enhanced by dielectric saturation. The first effect is able to predict high-frequency flow reversal in ACEO pumps, while the second may explain the decay of ICEO flow with increasing salt concentration. Through several colloidal examples, such as ICEP of an uncharged metal sphere in an asymmetric electrolyte, we show that nonlinear electrokinetic phenomena are generally ion-specific. Similar theoretical issues arise in nanofluidics (due to confinement) and ionic liquids (due to the lack of solvent), so the paper concludes with a general framework of modified electrokinetic equations for finite-sized ions.

Microbial fuel cell driving electrokinetic remediation of toxic metal contaminated soils.

Science.gov (United States)

Habibul, Nuzahat; Hu, Yi; Sheng, Guo-Ping

2016-11-15

An investigation of the feasibility of in-situ electrokinetic remediation for toxic metal contaminated soil driven by microbial fuel cell (MFC) is presented. Results revealed that the weak electricity generated from MFC could power the electrokinetic remediation effectively. The metal removal efficiency and its influence on soil physiological properties were also investigated. With the electricity generated through the oxidation of organics in soils by microorganisms, the metals in the soils would mitigate from the anode to the cathode. The concentrations of Cd and Pb in the soils increased gradually through the anode to the cathode regions after remediation. After about 143days and 108 days' operation, the removal efficiencies of 31.0% and 44.1% for Cd and Pb at the anode region could be achieved, respectively. Soil properties such as pH and soil conductivity were also significantly redistributed from the anode to the cathode regions. The study shows that the MFC driving electrokinetic remediation technology is cost-effective and environmental friendly, with a promising application in soil remediation. Copyright © 2016 Elsevier B.V. All rights reserved.

Development of complex electrokinetic decontamination method for soil contaminated with uranium

International Nuclear Information System (INIS)

Kim, Gye-Nam; Kim, Seung-Soo; Park, Hye-Min; Kim, Wan-Suk; Moon, Jei-Kwon; Hyeon, Jay-Hyeok

2012-01-01

520L complex electrokinetic soil decontamination equipment was manufactured to clean up uranium contaminated soils from Korean nuclear facilities. To remove uranium at more than 95% from the radioactive soil through soil washing and electrokinetic technology, decontamination experiments were carried out. To reduce the generation of large quantities of metal oxides in cathode, a pH controller is used to control the pH of the electrolyte waste solution between 0.5 and 1 for the formation of UO 2+ . More than 80% metal oxides were removed through pre-washing, an electrolyte waste solution was circulated by a pump, and a metal oxide separator filtered the metal oxide particles. 80–85% of the uranium was removed from the soil by soil washing as part of the pre-treatment. When the initial uranium concentration of the soil was 21.7 Bq/g, the required electrokinetic decontamination time was 25 days. When the initial concentration of 238 U in the soil was higher, a longer decontamination time was needed, but the removal rate of 238 U from the soil was higher.

Application of sequential extraction analysis to electrokinetic remediation of cadmium, nickel and zinc from contaminated soils

International Nuclear Information System (INIS)

Giannis, Apostolos; Pentari, Despina; Wang, Jing-Yuan; Gidarakos, Evangelos

2010-01-01

An enhanced electrokinetic process for the removal of cadmium (Cd), nickel (Ni) and zinc (Zn) from contaminated soils was performed. The efficiency of the chelate agents nitrilotriacetic acid (NTA), diethylenetriaminepentaacetic acid (DTPA) and diaminocycloexanetetraacetic acid (DCyTA) was examined under constant potential gradient (1.23 V/cm). The results showed that chelates were effective in desorbing metals at a high pH, with metal-chelate anion complexes migrating towards the anode. At low pH, metals existing as dissolved cations migrated towards the cathode. In such conflicting directions, the metals accumulated in the middle of the cell. Speciation of the metals during the electrokinetic experiments was performed to provide an understanding of the distribution of the Cd, Ni and Zn. The results of sequential extraction analysis revealed that the forms of the metals could be altered from one fraction to another due to the variation of physico-chemical conditions throughout the cell, such as pH, redox potential and the chemistry of the electrolyte solution during the electrokinetic treatment. It was found that binding forms of metals were changed from the difficult type to easier extraction type.

Application of sequential extraction analysis to electrokinetic remediation of cadmium, nickel and zinc from contaminated soils

Energy Technology Data Exchange (ETDEWEB)

Giannis, Apostolos, E-mail: apostolos.giannis@enveng.tuc.gr [Department of Environmental Engineering, Technical University of Crete, Politechnioupolis, Chania 73100 (Greece); Pentari, Despina [Department of Mineral Resources Engineering, Technical University of Crete, Politechnioupolis, Chania 73100 (Greece); Wang, Jing-Yuan [Residues and Resource Reclamation Centre (R3C), Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore); Gidarakos, Evangelos, E-mail: gidarako@mred.tuc.gr [Department of Environmental Engineering, Technical University of Crete, Politechnioupolis, Chania 73100 (Greece)

2010-12-15

An enhanced electrokinetic process for the removal of cadmium (Cd), nickel (Ni) and zinc (Zn) from contaminated soils was performed. The efficiency of the chelate agents nitrilotriacetic acid (NTA), diethylenetriaminepentaacetic acid (DTPA) and diaminocycloexanetetraacetic acid (DCyTA) was examined under constant potential gradient (1.23 V/cm). The results showed that chelates were effective in desorbing metals at a high pH, with metal-chelate anion complexes migrating towards the anode. At low pH, metals existing as dissolved cations migrated towards the cathode. In such conflicting directions, the metals accumulated in the middle of the cell. Speciation of the metals during the electrokinetic experiments was performed to provide an understanding of the distribution of the Cd, Ni and Zn. The results of sequential extraction analysis revealed that the forms of the metals could be altered from one fraction to another due to the variation of physico-chemical conditions throughout the cell, such as pH, redox potential and the chemistry of the electrolyte solution during the electrokinetic treatment. It was found that binding forms of metals were changed from the difficult type to easier extraction type.

Optimum Remediation Conditions of Vertical Electrokinetic-Flushing Equipment to Decontaminate a Radioactive Soil

International Nuclear Information System (INIS)

Kim, Gye Nam; Yang, Byeong IL; Moon, Jei Kwon; Lee, Kune Woo

2009-01-01

Vertical electrokintic-flushing remediation equipment was developed for the remediation of a radioactive soil near nuclear facilities. An optimum reagent was selected to decontaminate the radioactive soil near nuclear facilities with the developed vertical electrokintic-flushing remediation equipment, and the optimum remediation conditions were established to obtain a higher remediation efficiency. Namely, acetic acid was selected as an optimum reagent due to its higher remediation efficiency. When the electrokinetic remediation and the electrokinetic-flushing remediation results were compared, the removal efficiency of 4.6% and the soil waste solution volume of 1.5 times were increased in the electrokinetic remediation. When the potential gradient within an electrokinetic soil cell was increased by two times (4.0 V/cm), the removal efficiencies of Co 2+ and Cs + were increased by about 4.3%( Co 2+ : 98.9%, Cs + : 96.7%). Also, when the reagent concentration was increased from 0.01 M to 0.05 M, the removal efficiency of Co 2+ was increased but that of Cs + was decreased. Therefore, the optimum remediation conditions were that the acetic concentration was 0.01 M ∼ 0.05 M, the potential gradient was 4 V/cm, the injection of reagent 2.4 ml/g, and the remediation period was 20 days.

Impact of carbonate on the efficiency of heavy metal removal from kaolinite soil by the electrokinetic soil remediation method

Energy Technology Data Exchange (ETDEWEB)

Ouhadi, V.R., E-mail: vahidouhadi@yahoo.ca [Faculty of Engineering, Bu-Ali Sina University, Hamedan (Iran, Islamic Republic of); Yong, R.N. [RNY Geoenvironmental Research, North Saanich (Canada); Shariatmadari, N. [Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Saeidijam, S.; Goodarzi, A.R.; Safari-Zanjani, M. [Faculty of Engineering, Bu-Ali Sina University, Hamedan (Iran, Islamic Republic of)

2010-01-15

While the feasibility of using electrokinetics to decontaminate soils has been studied by several authors, the effects of soil composition on the efficiency of this method of decontamination has yet to be fully studied. This study focuses its attention on the effect of 'calcite or carbonate' (CaCO{sub 3}) on removal efficiency in electrokinetic soil remediation. Bench scale experiments were conducted on two soils: kaolinite and natural-soil of a landfill in Hamedan, Iran. Prescribed quantities of carbonates were mixed with these soils which were subsequently contaminated with zinc nitrate. After that, electrokinetic experiments were conducted to determine the efficiency of electrokinetic remediation. The results showed that an increase in the quantity of carbonate caused a noticeable increase on the contaminant retention of soil and on the resistance of soil to the contaminant removal by electrokinetic method. Because the presence of carbonates in the soil increases its buffering capacity, acidification is reduced, resulting in a decrease in the rate of heavy metal removed from the contaminant soil. This conclusion was validated by the evaluation of efficiency of electrokinetic method on a soil sample from the liner of a waste disposal site, with 28% carbonates.

Impact of carbonate on the efficiency of heavy metal removal from kaolinite soil by the electrokinetic soil remediation method

International Nuclear Information System (INIS)

Ouhadi, V.R.; Yong, R.N.; Shariatmadari, N.; Saeidijam, S.; Goodarzi, A.R.; Safari-Zanjani, M.

2010-01-01

While the feasibility of using electrokinetics to decontaminate soils has been studied by several authors, the effects of soil composition on the efficiency of this method of decontamination has yet to be fully studied. This study focuses its attention on the effect of 'calcite or carbonate' (CaCO 3 ) on removal efficiency in electrokinetic soil remediation. Bench scale experiments were conducted on two soils: kaolinite and natural-soil of a landfill in Hamedan, Iran. Prescribed quantities of carbonates were mixed with these soils which were subsequently contaminated with zinc nitrate. After that, electrokinetic experiments were conducted to determine the efficiency of electrokinetic remediation. The results showed that an increase in the quantity of carbonate caused a noticeable increase on the contaminant retention of soil and on the resistance of soil to the contaminant removal by electrokinetic method. Because the presence of carbonates in the soil increases its buffering capacity, acidification is reduced, resulting in a decrease in the rate of heavy metal removed from the contaminant soil. This conclusion was validated by the evaluation of efficiency of electrokinetic method on a soil sample from the liner of a waste disposal site, with 28% carbonates.

Electrokinetically Emplaced Amendments for Enhanced Bioremediation of Chlorinated Solvents in Clay: a Pilot Field Test

Science.gov (United States)

O'Carroll, D. M.; Inglis, A.; Head, N.; Chowdhury, A. I.; Garcia, A. N.; Reynolds, D. A.; Hogberg, D.; Edwards, E.; Lomheim, L.; Austrins, L. M.; Hayman, J.; Auger, M.; Sidebottom, A.; Eimers, J.; Gerhard, J.

2017-12-01

Bioremediation is an increasingly popular treatment technology for contaminated sites due to the proven success of biostimulation and bioaugmentation. However, bioremediation, along with other in-situ remediation technologies, faces limitations due to challenges with amendment delivery in low permeability media. Studies have suggested that electrokinetics (EK) can enhance the delivery of amendments in low permeability soils, such as clay. A pilot field trial was conducted to evaluate the potential for electrokinetics to support anaerobic dechlorination in clay by improving the transport of lactate and microorganisms. The study was performed on a former chlorinated solvent production facility in Ontario, Canada. Five transect cells were set up within the contaminated clay test area. Different amendments were injected in three of these cells to test various remediation strategies under the influence of EK. The other two cells were used as controls, one with EK applied and the other with no EK. This study focuses on the cell that applied electrokinetics for lactate emplacement followed by bioremediation (EK-Bio). This cell had an initial single injection of KB-1 bioaugmentation culture (SiREM, Canada) followed by injection of sodium lactate as a biostimulant while direct current was applied for 45 days between two electrodes 3 m apart. EK can enhance lactate migration by electromigration, while microorganisms have the potential to be influenced by electroosmosis of the bulk fluid or by electrophoresis of the charged bacteria themselves. All monitoring well locations in the EK-Bio cell exhibited evidence of successful lactate delivery corresponding to an increase in dissolved organic carbon. Reduction in chlorinated volatile organic compound (cVOC) concentrations, in particular 1,2-dichloroethane (1,2-DCA), were evident in monitoring locations coinciding with significant lactate breakthrough. Further investigation into the influence of EK-Bio on the abundance and

Electrokinetic sample preconcentration and hydrodynamic sample injection for microchip electrophoresis using a pneumatic microvalve.

Science.gov (United States)

Cong, Yongzheng; Katipamula, Shanta; Geng, Tao; Prost, Spencer A; Tang, Keqi; Kelly, Ryan T

2016-02-01

A microfluidic platform was developed to perform online electrokinetic sample preconcentration and rapid hydrodynamic sample injection for zone electrophoresis using a single microvalve. The polydimethylsiloxane microchip comprises a separation channel, a side channel for sample introduction, and a control channel which is used as a pneumatic microvalve aligned at the intersection of the two flow channels. The closed microvalve, created by multilayer soft lithography, serves as a nanochannel preconcentrator under an applied electric potential, enabling current to pass through while preventing bulk flow. Once analytes are concentrated, the valve is briefly opened and the stacked sample is pressure injected into the separation channel for electrophoretic separation. Fluorescently labeled peptides were enriched by a factor of ∼450 in 230 s. This method enables both rapid analyte concentration and controlled injection volume for high sensitivity, high-resolution CE. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrokinetic-enhanced phytoremediation of soils: status and opportunities.

Science.gov (United States)

Cameselle, Claudio; Chirakkara, Reshma A; Reddy, Krishna R

2013-10-01

Phytoremediation is a sustainable process in which green plants are used for the removal or elimination of contaminants in soils. Both organic and inorganic contaminants can be removed or degraded by growing plants by several mechanisms, namely phytoaccumulation, phytostabilization, phytodegradation, rhizofiltration and rhizodegradation. Phytoremediation has several advantages: it can be applied in situ over large areas, the cost is low, and the soil does not undergo significant damages. However, the restoration of a contaminated site by phytoremediation requires a long treatment time since the remediation depends on the growth and the biological cycles of the plant. It is only applicable for shallow depths within the reach of the roots, and the remediation efficiency largely depends on the physico-chemical properties of the soil and the bioavailability of the contaminants. The combination of phytoremediation and electrokinetics has been proposed in an attempt to avoid, in part, the limitations of phytoremediation. Basically, the coupled phytoremediation-electrokinetic technology consists of the application of a low intensity electric field to the contaminated soil in the vicinity of growing plants. The electric field may enhance the removal of the contaminants by increasing the bioavailability of the contaminants. Variables that affect the coupled technology are: the use of AC or DC current, voltage level and mode of voltage application (continuous or periodic), soil pH evolution, and the addition of facilitating agents to enhance the mobility and bioavailability of the contaminants. Several technical and practical challenges still remain that must be overcome through future research for successful application of this coupled technology at actual field sites. Copyright © 2013 Elsevier Ltd. All rights reserved.

Electrokinetic decontamination of concrete

Energy Technology Data Exchange (ETDEWEB)

Lomasney, H. [ISOTRON Corp., New Orleans, LA (United States)

1995-10-01

The U.S. Department of Energy has assigned a priority to the advancement of technology for decontaminating concrete surfaces which have become contaminated with radionuclides, heavy metals, and toxic organics. This agency is responsible for decontamination and decommissioning of thousands of buildings. Electrokinetic extraction is one of the several innovative technologies which emerged in response to this initiative. This technique utilizes an electropotential gradient and the subsequent electrical transport mechanism to cause the controlled movement of ionics species, whereby the contaminants exit the recesses deep within the concrete. This report discusses the technology and use at the Oak Ridge k-25 plant.

Superhydrophobic nanofluidic channels for enhanced electrokinetic conversion

Science.gov (United States)

Checco, Antonio; Al Hossain, Aktaruzzaman; Rahmani, Amir; Black, Charles; Doerk, Gregory; Colosqui, Carlos

2017-11-01

We present current efforts in the development of novel slit nanofluidic channels with superhydrophobic nanostructured surfaces designed to enhance hydrodynamic conductivity and improve selective transport and electrokinetic energy conversion efficiencies (mechanical-electrical energy conversion). The nanochannels are fabricated on silicon wafers using UV lithography, and their internal surface is patterned with conical nanostructures (feature size and spacing 30 nm) defined by block copolymer self-assembly and plasma etching. These nanostructures are rendered superhydrophobic by passivation with a hydrophobic silane monolayer. We experimentally characterize hydrodynamic conductivity, effective zeta potentials, and eletrokinetic flows for the patterned nanochannels, comparing against control channels with bare surfaces. Experimental observations are rationalized using both continuum-based modeling and molecular dynamics simulations. Scientific and technical knowledge produced by this work is particularly relevant for sustainable energy conversion and storage, separation processes and water treatment using nanoporous materials. The ONR Contract # N000141613178 and NSF-CBET award# 1605809.

Toxic Elements in Soil and Groundwater: Short-Time Study on Electrokinetic Removal of Arsenic in the Presence of other Ions

Directory of Open Access Journals (Sweden)

Hafiz Ahmad

2006-06-01

Full Text Available The electrokinetic technique is an emerging technology presently tested in situ to remove dissolved heavy metals from contaminated groundwater. There is a growing interest for using this system to cleanse clayey soil contaminated by toxic metallic ions. Currently, there are very few available non-destructive treatment methods that could be successfully applied in situ on low permeable type of soil matrix. The main objective of presented study was to validate and possibly enhance the overall efficiency of decontamination by the electrokinetic technique of the low permeable soil polluted by the arsenic in combination with chromium and copper ions. The chosen mixture of ions was imitating leak of pesticide well known as chromate copper arsenate (CCA. The chosen technique is showing a big promise to be used in the future as a portable, easy to install and run on sites with spills or leaks hard to reach otherwise; such as in the dense populated and urbanized areas. Laboratory electrokinetic experiments were designed to understand and possibly manipulate main mechanisms involved during forced migration of ions. All tests were conducted on artificially contaminated kaolinite (low permeable clay soil. Electrokinetic migration was inducted by the low voltage dc current applied through soil column. Series of experiments were designed to assess the efficiency of arsenic-chromium-copper remediation by applying (1 only dc current; and (2 by altering the soil environment. Obtained results showed that arsenic could be successfully removed from the soil in one day (25 hours span. It was significant time reduction, very important during emergency response. Mass recovered at the end of each test depended on initial condition of soil and type of flushing solution. The best results were obtained, when soil was flushed with either NaOH or NaOCl (total removal efficiency 74.4% and 78.1%, respectively. Direct analysis of remained arsenic in soil after these tests

On Developing Field-Effect-Tunable Nanofluidic Ion Diodes with Bipolar, Induced-Charge Electrokinetics

Directory of Open Access Journals (Sweden)

Ye Tao

2018-04-01

Full Text Available We introduce herein the induced-charge electrokinetic phenomenon to nanometer fluidic systems; the design of the nanofluidic ion diode for field-effect ionic current control of the nanometer dimension is developed by enhancing internal ion concentration polarization through electrochemical transport of inhomogeneous inducing-counterions resulting from double gate terminals mounted on top of a thin dielectric layer, which covers the nanochannel connected to microfluidic reservoirs on both sides. A mathematical model based on the fully-coupled Poisson-Nernst-Plank-Navier-Stokes equations is developed to study the feasibility of this structural configuration causing effective ionic current rectification. The effect of various physiochemical and geometrical parameters, such as the native surface charge density on the nanochannel sidewalls, the number of gate electrodes (GE, the gate voltage magnitude, and the solution conductivity, permittivity, and thickness of the dielectric coating, as well as the size and position of the GE pair of opposite gate polarity, on the resulted rectification performance of the presented nanoscale ionic device is numerically analyzed by using a commercial software package, COMSOL Multiphysics (version 5.2. Three types of electrohydrodynamic flow, including electroosmosis of 1st kind, induced-charge electroosmosis, and electroosmosis of 2nd kind that were originated by the Coulomb force within three distinct charge layers coexist in the micro/nanofluidic hybrid network and are shown to simultaneously influence the output current flux in a complex manner. The rectification factor of a contrast between the ‘on’ and ‘off’ working states can even exceed one thousand-fold in the case of choosing a suitable combination of several key parameters. Our demonstration of field-effect-tunable nanofluidic ion diodes of double external gate electrodes proves invaluable for the construction of a flexible electrokinetic platform

Monitoring of electrokinetic in-situ-decontamination

Energy Technology Data Exchange (ETDEWEB)

Goldmann, T. [INTUS Inst. fuer Technologie und Umweltschutz e.V., Berlin (Germany)

2001-07-01

The need for a monitoring system for in-situ soil decontamination is two-fold: Firstly, to ensure that remediation is attained and secondly to minimize costs and treatment time. A further reason is the potential risk of unexpected mobilization or chemical generation of hazardous compounds which could result in an extension of the contamination into other regions of soil, the ground water or the atmosphere. Electrokinetic in-situ decontamination is based on transport processes in the ground that proceed with relatively low velocity. This results in treatment times of several months. Since the transport processes can be described by a mathematical model, monitoring should always be combined with qualified mathematical processing. This makes it possible to estimate treatment time and costs to be expected. The challenge of in-situ monitoring is to identify relevant parameters describing the state of the ground. These parameters must be independent from influences like weather but they must be sensitive to changes of soil characteristics. In the case of electrokinetic soil remediation, probes and sensors must be resistant to influences of electric fields. The function of sensors or measuring systems can be disturbed or even damaged or destroyed by electric fields (for example by electro-corrosion). (orig.)

Electrokinetic desalination of glazed ceramic tiles

DEFF Research Database (Denmark)

Ottosen, Lisbeth M.; Ferreira, Celia; Christensen, Iben Vernegren

2010-01-01

Electrokinetic desalination is a method where an applied electric DC field is the driving force for removal of salts from porous building materials. In the present paper, the method is tested in laboratory scale for desalination of single ceramic tiles. In a model system, where a tile...... was contaminated with NaCl during submersion and subsequently desalinated by the method, the desalination was completed in that the high and problematic initial Cl(-) concentration was reduced to an unproblematic concentration. Further conductivity measurements showed a very low conductivity in the tile after...... treatment, indicating that supply of ions from the poultice at the electrodes into the tile was limited. Electroosmotic transport of water was seen when low ionic content was reached. Experiments were also conducted with XVIII-century tiles, which had been removed from Palacio Centeno (Lisbon) during...

Application of micellar electrokinetic capillary chromatography for routine analysis of different materials

Directory of Open Access Journals (Sweden)

Injac Rade

2008-01-01

Full Text Available Micellar electrokinetic capillary chromatography (MEKC has become a popular mode among the several capillary electro-migration techniques. Most drug analysis can be performed by using MEKC because of its wide applicability. Separation of very complex mixtures, determination of drugs in the biological materials, etc., can be successfully achieved by MEKC. This review surveys typical applications of MEKC analysis. Recent advances in MEKC, especially with solid-phase extraction and large-volume sample stacking, are described. Modes of electrokinetic chromatography including MEKC, a separation theory of MEKC, environmental friendly analysis, and selectivity manipulation in MEKC are also briefly mentioned.

The Use of Electrical Resistivity Method to Mapping The Migration of Heavy Metals by Electrokinetic

Science.gov (United States)

Azhar, A. T. S.; Ayuni, S. A.; Ezree, A. M.; Nizam, Z. M.; Aziman, M.; Hazreek, Z. A. M.; Norshuhaila, M. S.; Zaidi, E.

2017-08-01

The presence of heavy metals contamination in soil environment highly needs innovative remediation. Basically, this contamination was resulted from ex-mining sites, motor workshop, petrol station, landfill and industrial sites. Therefore, soil treatment is very important due to metal ions are characterized as non-biodegradable material that may be harmful to ecological system, food chain, human health and groundwater sources. There are various techniques that have been proposed to eliminate the heavy metal contamination from the soil such as bioremediation, phytoremediation, electrokinetic remediation, solidification and stabilization. The selection of treatment needs to fulfill some criteria such as cost-effective, easy to apply, green approach and high remediation efficiency. Electrokinetic remediation technique (EKR) offers those solutions in certain area where other methods are impractical. While, electrical resistivity method offers an alternative geophysical technique for soil subsurface profiling to mapping the heavy metals migration by the influece of electrical gradient. Consequently, this paper presents an overview of the use of EKR to treat contaminated soil by using ERM method to verify their effectiveness to remove heavy metals.

Effect of physical, chemical and electro-kinetic properties of pumice samples on radiation shielding properties of pumice material

International Nuclear Information System (INIS)

Tapan, Mücip; Yalçın, Zeynel; İçelli, Orhan; Kara, Hüsnü; Orak, Salim; Özvan, Ali; Depci, Tolga

2014-01-01

Highlights: • Radiation shielding properties of pumice materials are studied. • The relationship between physical, chemical and electro-kinetic properties pumice samples is identified. • The photon atomic parameters are important for the absorber peculiarity of the pumices. - Abstract: Pumice has been used in cement, concrete, brick, and ceramic industries as an additive and aggregate material. In this study, some gamma-ray photon absorption parameters such as the total mass attenuation coefficients, effective atomic number and electronic density have been investigated for six different pumice samples. Numerous values of energy related parameters from low energy (1 keV) to high energy (100 MeV) were calculated using WinXCom programme. The relationship between radiation shielding properties of the pumice samples and their physical, chemical and electro-kinetic properties was evaluated using simple regression analysis. Simple regression analysis indicated a strong correlation between photon energy absorption parameters and density and SiO 2 , Fe 2 O 3 , CaO, MgO, TiO 2 content of pumice samples in this study. It is found that photon energy absorption parameters are not related to electro-kinetic properties of pumice samples

Probing size-dependent electrokinetics of hematite aggregates

Energy Technology Data Exchange (ETDEWEB)

Kedra-Królik, Karolina; Rosso, Kevin M.; Zarzycki, Piotr

2017-02-01

Aqueous particle suspensions of many kinds are stabilized by the electrostatic potential developed at their surfaces from reaction with water and ions. An important and less well understood aspect of this stabilization is the dependence of the electrostatic surface potential on particle size. Surface electrostatics are typically probed by measuring particle electrophoretic mobilities and quantified in the electrokinetic potential (f), using commercially available Zeta Potential Analyzers (ZPA). Even though ZPAs provide frequency-spectra (histograms) of electrophoretic mobility and hydrodynamic diameter, typically only the maximal-intensity values are reported, despite the information in the remainder of the spectra. Here we propose a mapping procedure that inter-correlates these histograms to extract additional insight, in this case to probe particle size-dependent electrokinetics. Our method is illustrated for a suspension of prototypical iron (III) oxide (hematite, a-Fe2O3). We found that the electrophoretic mobility and f-potential are a linear function of the aggregate size. By analyzing the distribution of surface site types as a function of aggregate size we show that site coordination increases with increasing aggregate diameter. This observation explains why the acidity of the iron oxide particles decreases with increasing particle size.

Particle morphology and mineral structure of heavy metal-contaminated kaolin soil before and after electrokinetic remediation.

Science.gov (United States)

Roach, Nicole; Reddy, Krishna R; Al-Hamdan, Ashraf Z

2009-06-15

This study aims to characterize the physical distribution of heavy metals in kaolin soil and the chemical and structural changes in kaolinite minerals that result from electrokinetic remediation. Three bench-scale electrokinetic experiments were conducted on kaolin that was spiked with Cr(VI) alone, Ni (II) alone, and a combination of Cr(VI), Ni(II) and Cd(II) under a constant electric potential of 1VDC/cm for a total duration of 4 days. Transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) analyses were performed on the soil samples before and after electrokinetic remediation. Results showed that the heavy metal contaminant distribution in the soil samples was not observable using TEM and EDX. EDX detected nickel and chromium on some kaolinite particles and titanium-rich, high-contrast particles, but no separate phases containing the metal contaminants were detected. Small amounts of heavy metal contaminants that were detected by EDX in the absence of a visible phase suggest that ions are adsorbed to kaolinite particle surfaces as a thin coating. There was also no clear correlation between semiquantitative analysis of EDX spectra and measured total metal concentrations, which may be attributed to low heavy metal concentrations and small size of samples used. X-ray diffraction analyses were aimed to detect any structural changes in kaolinite minerals resulting from EK. The diffraction patterns showed a decrease in peak height with decreasing soil pH value, which indicates possible dissolution of kaolinite minerals during electrokinetic remediation. Overall this study showed that the changes in particle morphology were found to be insignificant, but a relationship was found between the crystallinity of kaolin and the pH changes induced by the applied electric potential.

Particle morphology and mineral structure of heavy metal-contaminated kaolin soil before and after electrokinetic remediation

International Nuclear Information System (INIS)

Roach, Nicole; Reddy, Krishna R.; Al-Hamdan, Ashraf Z.

2009-01-01

This study aims to characterize the physical distribution of heavy metals in kaolin soil and the chemical and structural changes in kaolinite minerals that result from electrokinetic remediation. Three bench-scale electrokinetic experiments were conducted on kaolin that was spiked with Cr(VI) alone, Ni (II) alone, and a combination of Cr(VI), Ni(II) and Cd(II) under a constant electric potential of 1 VDC/cm for a total duration of 4 days. Transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) analyses were performed on the soil samples before and after electrokinetic remediation. Results showed that the heavy metal contaminant distribution in the soil samples was not observable using TEM and EDX. EDX detected nickel and chromium on some kaolinite particles and titanium-rich, high-contrast particles, but no separate phases containing the metal contaminants were detected. Small amounts of heavy metal contaminants that were detected by EDX in the absence of a visible phase suggest that ions are adsorbed to kaolinite particle surfaces as a thin coating. There was also no clear correlation between semiquantitative analysis of EDX spectra and measured total metal concentrations, which may be attributed to low heavy metal concentrations and small size of samples used. X-ray diffraction analyses were aimed to detect any structural changes in kaolinite minerals resulting from EK. The diffraction patterns showed a decrease in peak height with decreasing soil pH value, which indicates possible dissolution of kaolinite minerals during electrokinetic remediation. Overall this study showed that the changes in particle morphology were found to be insignificant, but a relationship was found between the crystallinity of kaolin and the pH changes induced by the applied electric potential.

Reduction of waste solution volume generated on electrokinetic remediation

Energy Technology Data Exchange (ETDEWEB)

Kim, Gye-Nam; Koo, Dae-Seo; Kim, Seung-Soo; Jeong, Jung-Whan; Han, Gyu-Seong; Moon, Jei-Kwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-05-15

In this study, for the reduction of volume of metal oxides generated in cathode chamber, the optimum pH of waste electrolyte in cathode chamber were drawn out through several experiments with the manufactured electrokinetic decontamination equipment. Also, the required time to reach to below the clearance concentration level for self- disposal was estimated through experiments using the manufactured electrokinetic decontamination equipment. A diagram of soil decontamination process for the removal of uranium from contaminated soil was drawn out. The optimum pH of waste electrolyte in cathode chamber for the reduction of volume of metal oxides was below 2.35. Also, when the initial uranium concentration of the soils were 7-20 Bq/g, the required times to reach to below the clearance concentration level for self- disposal were 25-40 days. A diagram of soil decontamination process for the removal of uranium from contaminated soil was drawn out.

Spectral induced polarization for monitoring electrokinetic remediation processes

Science.gov (United States)

Masi, Matteo; Losito, Gabriella

2015-12-01

Electrokinetic remediation is an emerging technology for extracting heavy metals from contaminated soils and sediments. This method uses a direct or alternating electric field to induce the transport of contaminants toward the electrodes. The electric field also produces pH variations, sorption/desorption and precipitation/dissolution of species in the porous medium during remediation. Since heavy metal mobility is pH-dependent, the accurate control of pH inside the material is required in order to enhance the removal efficiency. The common approach for monitoring the remediation process both in laboratory and in the field is the chemical analysis of samples collected from discrete locations. The purpose of this study is the evaluation of Spectral Induced Polarization as an alternative method for monitoring geochemical changes in the contaminated mass during remediation. The advantage of this technique applied to field-scale is to offer higher resolution mapping of the remediation site and lower cost compared to the conventional sampling procedure. We carried out laboratory-scale electrokinetic remediation experiments on fine-grained marine sediments contaminated by heavy metal and we made Spectral Induced Polarization measurements before and after each treatment. Measurements were done in the frequency range 10- 3-103 Hz. By the deconvolution of the spectra using the Debye Decomposition method we obtained the mean relaxation time and total chargeability. The main finding of this work is that a linear relationship exists between the local total chargeability and pH, with good agreement. The observed behaviour of chargeability is interpreted as a direct consequence of the alteration of the zeta potential of the sediment particles due to pH changes. Such relationship has a significant value for the interpretation of induced polarization data, allowing the use of this technique for monitoring electrokinetic remediation at field-scale.

Feasibility of electrokinetic oxygen supply for soil bioremediation purposes.

Science.gov (United States)

Mena Ramírez, E; Villaseñor Camacho, J; Rodrigo Rodrigo, M A; Cañizares Cañizares, P

2014-12-01

This paper studies the possibility of providing oxygen to a soil by an electrokinetic technique, so that the method could be used in future aerobic polluted soil bioremediation treatments. The oxygen was generated from the anodic reaction of water electrolysis and transported to the soil in a laboratory-scale electrokinetic cell. Two variables were tested: the soil texture and the voltage gradient. The technique was tested in two artificial soils (clay and sand) and later in a real silty soil, and three voltage gradients were used: 0.0 (control), 0.5, and 1.0 V cm(-1). It was observed that these two variables strongly influenced the results. Oxygen transport into the soil was only available in the silty and sandy soils by oxygen diffusion, obtaining high dissolved oxygen concentrations, between 4 and 9 mg L(-1), useful for possible aerobic biodegradation processes, while transport was not possible in fine-grained soils such as clay. Electro-osmotic flow did not contribute to the transport of oxygen, and an increase in voltage gradients produced higher oxygen transfer rates. However, only a minimum fraction of the electrolytically generated oxygen was efficiently used, and the maximum oxygen transport rate observed, approximately 1.4 mgO2 L(-1)d(-1), was rather low, so this technique could be only tested in slow in-situ biostimulation processes for organics removal from polluted soils. Copyright © 2014 Elsevier Ltd. All rights reserved.

Removal of heavy metals from kaolin using an upward electrokinetic soil remedial (UESR) technology

International Nuclear Information System (INIS)

Wang, J.-Y.; Huang, X.-J.; Kao, Jimmy C.M.; Stabnikova, Olena

2006-01-01

An upward electrokinetic soil remedial (UESR) technology was proposed to remove heavy metals from contaminated kaolin. Unlike conventional electrokinetic treatment that uses boreholes or trenches for horizontal migration of heavy metals, the UESR technology, applying vertical non-uniform electric fields, caused upward transportation of heavy metals to the top surface of the treated soil. The effects of current density, treatment duration, cell diameter, and different cathode chamber influent (distilled water or 0.01 M nitric acid) were studied. The removal efficiencies of heavy metals positively correlated to current density and treatment duration. Higher heavy metals removal efficiency was observed for the reactor cell with smaller diameter. A substantial amount of heavy metals was accumulated in the nearest to cathode 2 cm layer of kaolin when distilled water was continuously supplied to the cathode chamber. Heavy metals accumulated in this layer of kaolin can be easily excavated and disposed off. The main part of the removed heavy metals was dissolved in cathode chamber influent and moved away with cathode chamber effluent when 0.01 M nitric acid was used, instead of distilled water. Energy saving treatment by UESR technology with highest metal removal efficiencies was provided by two regimes: (1) by application of 0.01 M nitric acid as cathode chamber influent, cell diameter of 100 mm, duration of 18 days, and constant voltage of 3.5 V (19.7 kWh/m 3 of kaolin) and (2) by application of 0.01 M nitric acid as cathode chamber influent, cell diameter of 100 cm, duration of 6 days, and constant current density of 0.191 mA/cm 2 (19.1 kWh/m 3 of kaolin)

Some basic requirements for the application of electrokinetic methods for the reconstruction of masonry with rising humidity

Energy Technology Data Exchange (ETDEWEB)

Friese, P; Jacobasch, H J; Boerner, M

1987-12-01

Based on some theoretical statements concerning the electro-osmosis the most important requirements for the application of electrokinetic methods for drying masonry with rising humidity are described. Samples of brick masonry (brick and mortar) were examined by means of an electrokinetic measuring system (EKM) with different electrolytes (CaSO/sub 4/ and KCl) being used for different concentrations. It was found for all samples, that the zeta potential is provided with a negative sign and that the absolute value of the zeta potential approaches zero with increasing electrolyte concentration. Based on these measurements, an upper limit of the electrolyte concentration of 0.1 Mol/liter is established for the application of electrokinetic methods for drying masonry.

Electrokinetic Flow in Microchannels with Finite Reservoir Size Effects

International Nuclear Information System (INIS)

Yan, D; Yang, C; Nguyen, N-T; Huang, X

2006-01-01

In electrokinetically-driven microfluidic applications, reservoirs are indispensable and have finite sizes. During operation processes, as the liquid level difference in reservoirs keeps changing as time elapses, the flow characteristics in a microchannel exhibit a combination of the electroosmotic flow and the time-dependent induced backpressure-driven flow. In this work, an assessment of the finite reservoir size effect on electroosmotic flows is presented theoretically and experimentally. A model is developed to describe the timedependent electrokinetic flow with finite reservoir size effects. The theoretical analysis shows that under certain conditions the finite reservoir size effect is significant. The important parameters that describe the effect of finite reservoir size on the flow characteristics are discussed. A new concept denoted as 'effective pumping period' is introduced to characterize the reservoir size effect. The proposed model clearly identifies the mechanisms of the finitereservoir size effects and is further confirmed by using micro-PIV technique. The results of this study can be used for facilitating the design of microfluidic devices

The characterizations of rheological, electrokinetical and structural properties of ODTABr/MMT and HDTABr/MMT organoclays

International Nuclear Information System (INIS)

Isci, S.; Uslu, Y.O.; Ece, O.I.

2009-01-01

In the present paper, we have investigated as a function of surfactant concentration the rheological (yield value, plastic viscosity) and electrokinetic (mobility, zeta potential) properties of montmorillonite (MMT) dispersions. The influence of surfactants (Octadeccyltrimethylammonium bromide, ODTABr and Hexadecyltrimethylammonium bromide, HDTABr) on dispersions of Na-activated bentonite was evaluated by rheological and electrokinetic measurements, and X-ray diffraction (XRD) studies. The interactions between clay minerals and surfactants in water-based Na-activated MMT dispersions (2 wt.%) were examined in detail using rheologic parameters, such as viscosity, yield point, apparent and plastic viscosity, hysteresis area, and electrokinetic parameters of mobility and zeta potentials, and XRD also analyses helped to determine swelling properties of d-spacings. MMT and organoclay dispersions showed Bingham Plastic flow behavior. The zeta potential measurements displayed that the surfactant molecules hold on the clay particle surfaces and the XRD analyses displayed that they get into the basal layers

ELECTROKINETIC REMEDIATION STUDY FOR CADMIUM CONTAMINATED SOIL

OpenAIRE

P. Bala Ramudu; R. P. Tiwari; R. K. Srivastava

2007-01-01

This paper presents the results of an experimental research undertaken to evaluate different purging solutions to enhance the removal of cadmium from spiked contaminated field soil by electrokinetic remediation. Three experiments were conducted when soil was saturated with deionised water and subsequently deionised water, ammonium citrate and sodium citrate were used as purging solutions at anode end. One experiment was conducted when the soil was saturated with ammonium citrate and itself wa...

Electrokinetic and electrochemical corrosion studies related to crud formation

International Nuclear Information System (INIS)

Scenini, Fabio; Palumbo, Gaetano; Stevens, Nicholas; Cook, Tony; Banks, Andrew

2012-09-01

A potentially important mechanism for the flow-induced deposition of CRUD from pressurised high temperature primary water is the effect of 'streaming potentials' that develop across the electrochemical double layer of a metallic surface as a result of fluid flow across a pressure gradient or orifice. Thus, under such conditions, streaming currents develop normal to a surface and may result in preferential oxidation, for example of dissolved ferrous to ferric ions with their subsequent deposition as an oxide. The approach presented in this paper was to consider the electrokinetic problem is to firstly consider the magnitude of currents that can be developed under a given set of flow/mass transport conditions and, secondly, to consider the way in which these relatively small currents might give rise to oxide deposition. Electrochemical measurements on 304L samples were carried out over a range of temperatures in hydrogenated, alkaline water. The test conditions were chosen in order to simulate PWR primary water conditions. Furthermore, in order to facilitate the electrochemical studies, the ferrous ion concentration in the solution was also enhanced by the presence of a mild steel plate left in the autoclave to corrode. By employing the cyclic voltammetry technique interpreted using the Randles-Sevcik equation it was possible to calculate the concentration of ferrous ions and their diffusion coefficient. A miniature flow cell was designed for the purpose of creating regions of accelerated flow with consequent formation of anodic and cathodic regions so as to be able to measure the streaming currents. A study was carried out in order to better understand the potential which is associated with the streaming potential as function of the velocity and temperature at fixed pH. (authors)

Exploring driving forces and liquid properties for electrokinetic energy conversion

NARCIS (Netherlands)

Nguyen, Trieu

2015-01-01

This thesis presents an effort to understand electrokinetic energy conversion systems which are based on motion of ionic charges in micro- and nano-confinements. In particular, both experimentally and theoretically the utilization of different kind of liquids was investigated to convert mechanical

Electrokinetic transport of aerobic microorganisms under low-strength electric fields.

Science.gov (United States)

Maillacheruvu, Krishnanand Y; Chinchoud, Preethi R

2011-01-01

To investigate the feasibility of utilizing low strength electric fields to transport commonly available mixed cultures such as those from an activated sludge process, bench scale batch reactor studies were conducted in sand and sandy loam soils. A readily biodegradable substrate, dextrose, was used to test the activity of the transported microorganisms. Electric field strengths of 7V, 10.5V, and 14V were used. Results from this investigation showed that an electric field strength of 0.46 Volts per cm was sufficient to transport activated sludge microorganisms across a sandy loam soil across a distance of about 8 cm in 72 h. More importantly, the electrokinetically transported microbial culture remained active and viable after the transport process and was biodegrade 44% of the dextrose in the soil medium. Electrokinetic treatment without microorganisms resulted in removal of 37% and the absence of any treatment yielded a removal of about 15%.

Electrokinetic remediation of anionic contamination from unsaturated soil: Field application

International Nuclear Information System (INIS)

Lindgren, E.R.; Mattson, E.D.

1995-01-01

Electrokinetic remediation is an in situ technique under development at Sandia National Laboratories for removal of ionic contaminants from soil. While to date most other studies of this technique have focused on saturated soils, usually clays, the work at Sandia has been to extend the process to unsaturated sandy soils typical of arid regions. The impetus for this study is a chromate plume located beneath an old Sandia chemical waste landfill. Working in unsaturated soils is complicated by moisture control requirements, both to prevent undesired hydraulic transport of contamination outside the treatment zone and to optimize soil properties for efficient electrokinetic remediation. Two field tests will be discussed. First, a field test in clean soil is in progress to demonstrate moisture control with the Sandia electrode system. The second field demonstration, planned to begin the Fall of 1995, involves chromate removal from a in a chemical waste landfill

Phosphorus recovery from sewage sludge by an electrokinetic process

DEFF Research Database (Denmark)

Ribeiro, A.B.; Couto, N.; Mateus, E.P.

to supply P for the next ca. 80 years. Additionaly, the quality of this raw material has deteriorated due to contamination, which has increased processing costs of mineral P fertilizers. The recovery of nutrients, like P, from secondary resources urges. Sewage sludge (SS) and sewage sludge ash (SSA) from...... waste water treatment plants (WWTP) may contain contaminants or unwanted elements regarding specific applications, but they also contain secondary resources of high value. Using these ash as a P resource, while removing the contaminants, seems a sustainable option. The electrokinetic (EK) process can....... This communication aims to discuss preliminary results of the feasibility of EK process to recover P from WWTP target wastes....

Electrokinetic control of sample splitting at a channel bifurcation using isotachophoresis

International Nuclear Information System (INIS)

Persat, Alexandre; Santiago, Juan G

2009-01-01

We present a novel method for accurately splitting ionic samples at microchannel bifurcations. We leverage isotachophoresis (ITP) to focus and transport sample through a one-inlet, two-outlet microchannel bifurcation. We actively control the proportion of splitting by controlling potentials at end-channel reservoirs (and thereby controlling the current ratio). We explore the effect of buffer chemistry and local electric field on splitting dynamics and propose and validate a simple Kirchoff-type rule controlling the split ratio. We explore the effects of large applied electric fields on sample splitting and attribute a loss of splitting accuracy to electrohydrodynamic instabilities. We propose a scaling analysis to characterize the onset of this instability. This scaling is potentially useful for other electrokinetic flow problems with self-sharpening interfaces.

Modeling of electrokinetic desalination of bricks

DEFF Research Database (Denmark)

Paz-Garcia, Juan Manuel; Johannesson, Björn; Ottosen, Lisbeth M.

2012-01-01

A model for the reactive transport of matter through porous media induced by an externally applied electric field is discussed. The Nernst–Planck–Poisson system of equations is used for modeling multi-species electro-diffusion transport phenomena, assuming chemical equilibrium during the process....... The system of equations includes the transport of water and the resulting advective flow of the aqueous species. The model takes into account transient change in porosity and its impact on transport. Test examples were performed and compared to experimental data for electrokinetic desalination treatment...

Basic principles of electrolyte chemistry for microfluidic electrokinetics. Part I: Acid-base equilibria and pH buffers.

Science.gov (United States)

Persat, Alexandre; Chambers, Robert D; Santiago, Juan G

2009-09-07

We review fundamental and applied acid-base equilibrium chemistry useful to microfluidic electrokinetics. We present elements of acid-base equilibrium reactions and derive rules for pH calculation for simple buffers. We also present a general formulation to calculate pH of more complex, arbitrary mixtures of electrolytes, and discuss the effects of ionic strength and temperature on pH calculation. More practically, we offer advice on buffer preparation and on buffer reporting. We also discuss "real world" buffers and likely contamination sources. In particular, we discuss the effects of atmospheric carbon dioxide on buffer systems, namely, the increase in ionic strength and acidification of typical electrokinetic device buffers. In Part II of this two-paper series, we discuss the coupling of acid-base equilibria with electrolyte dynamics and electrochemistry in typical microfluidic electrokinetic systems.

Electrokinetic treatment of firing ranges containing tungsten-contaminated soils

International Nuclear Information System (INIS)

Braida, Washington; Christodoulatos, Christos; Ogundipe, Adebayo; Dermatas, Dimitris; O'Connor, Gregory

2007-01-01

Tungsten-based alloys and composites are being used and new formulations are being considered for use in the manufacturing of different types of ammunition. The use of tungsten heavy alloys (WHA) in new munitions systems and tungsten composites in small caliber ammunition could potentially release substantial amounts of this element into the environment. Although tungsten is widely used in industrial and military applications, tungsten's potential environmental and health impacts have not been thoroughly addressed. This necessitates the research and development of remedial technologies to contain and/or remove tungsten from soils that may serve as a source for water contamination. The current work investigates the feasibility of using electrokinetics for the remediation of tungsten-contaminated soils in the presence of other heavy metals of concern such as Cu and Pb with aim to removing W from the soil while stabilizing in situ, Pb and Cu

Modeling of Electrokinetic Processes Using the Nernst-Plank-Poisson System

DEFF Research Database (Denmark)

Paz-Garcia, Juan Manuel; Johannesson, Björn; Ottosen, Lisbeth M.

2010-01-01

Electrokinetic processes are known as the mobilization of species within the pore solution of porous materials under the effect of an external electric field. A finite elements model was implemented and used for the integration of the coupled Nernst-Plank-Poisson system of equations in order...

Use of cation selective membrane and acid addition for PH control in two-dimensional electrokinetic remediation of copper

Energy Technology Data Exchange (ETDEWEB)

Chan, M.S.M.; Lynch, R.J. [Cambridge Univ., Engineering Dept. (United Kingdom); Ilett, D.J. [AEA Technology, Harwell, Oxfordshire (United Kingdom)

2001-07-01

The feasibility of using a combination of a cation selective membrane and acid addition for pH control in electrokinetic remediation to toxic and heavy metals from low-permeability soil has been investigated. The high pH generated during the remediation process, as a result of surplus OH{sup -} ions, may cause metal ions to precipitate as hydroxides at or near the cathodes. This region of high pH is known to be associated with high electrical resistance, which limits the remediation efficiency by inhibiting current flow through the soil. One way to control pH is by adding acid to neutralize the OH{sup -} ions. However, preliminary work showed that addition of acid to the cathodic region was not effective in preventing the spread of the alkaline zone from cathodes toward anodes. Precipitates were formed before metal ions reached the cathodic region. Therefore, another method of pH control was investigated, using a cation selective membrane to enhance the electrokinetic process. The membrane was placed in front of the cathodes to contain the OH{sup -} ions generated, and confine the precipitates of metal hydroxide to a small cathodic region. The clean-up of a contaminated site was modelled in a rectangular tank, using silt as the low permeability soul and copper to simulate the contamination. The objective was to redistribute the contaminant so as to concentrate it into a small area. Three experiments were performed with the following methods of pH control: (1) acid addition, (2) use of a cation selective membrane and (3) a combination of acid addition and a cation selective membrane. Using the combined approach, it was found that 75% of the target clean-up section (bounded by the cation selective membrane and the anodes) had more than 40% of the initial copper removed. The general efficiency of remediation increased in the following order. (orig.)

Application of electrokinetic soil flushing to four herbicides: A comparison.

Science.gov (United States)

dos Santos, E Vieira; Souza, F; Saez, C; Cañizares, P; Lanza, M R V; Martinez-Huitle, C A; Rodrigo, M A

2016-06-01

In this work, four bench-scale plants containing soil spiked with four herbicides (2,4-Dichlorophenoxyacetic acid (2,4-D), oxyfluorfen, chlorsulfuron and atrazine) undergo treatment consisting of an electrokinetic soil flushing (EKSF). Results clearly demonstrate that efficiency of EKSF depends on the chemical characteristic of the pesticide used. The amount of pesticide collected in the anode well is more significant than that collected in the cathode wells, indicating that the electromigration is much more important than drainage by electro-osmotic flux for this application. After 15 d of treatment, the 2,4-D is the pesticide most efficiently removed (95% of removal), while chlorsulfuron is the pesticide more resilient to the treatment. Additionally, volatilization was found to be a process of the major significance in the application of electrokinetic techniques to soil polluted with herbicides and because of that it should always be taken into account in the future design of full-scale processes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Capillary sieving electrophoresis and micellar electrokinetic capillary chromatography produce highly correlated separation of tryptic digests

Science.gov (United States)

Dickerson, Jane A.; Dovichi, Norman J.

2011-01-01

We perform two-dimensional capillary electrophoresis on fluorescently labeled proteins and peptides. Capillary sieving electrophoresis was performed in the first dimension and micellar electrokinetic capillary chromatography was performed in the second. A cellular homogenate was labeled with the fluorogenic reagent FQ and separated using the system. This homogenate generated a pair of ridges; the first had essentially constant migration time in the CSE dimension, while the second had essentially constant migration time in the MEKC dimension. In addition a few spots were scattered through the electropherogram. The same homogenate was digested using trypsin, and then labeled and subjected to the two dimensional separation. In this case, the two ridges observed from the original two-dimensional separation disappeared, and were replaced by a set of spots that fell along the diagonal. Those spots were identified using a local-maximum algorithm and each was fit using a two-dimensional Gaussian surface by an unsupervised nonlinear least squares regression algorithm. The migration times of the tryptic digest components were highly correlated (r = 0.862). When the slowest migrating components were eliminated from the analysis, the correlation coefficient improved to r = 0.956. PMID:20564272

Self-assembled silver nanoparticles monolayers on mica-AFM, SEM, and electrokinetic characteristics

International Nuclear Information System (INIS)

Oćwieja, Magdalena; Morga, Maria; Adamczyk, Zbigniew

2013-01-01

A monodisperse silver particle suspension was produced by a chemical reduction method in an aqueous medium using sodium citrate. The average particle size determined by dynamic light scattering (DLS), transmission electron microscopy (TEM), and atomic force microscopy (AFM) was 28.5 nm. The DLS measurements confirmed that the suspension was stable for the ionic strength up to 3 × 10 −2 M NaCl. The electrophoretic mobility measurements revealed that the electrokinetic charge of particles was negative for pH range 3–10, assuming −50 e for pH = 9 and 0.01 M NaCl. Using the suspension, silver particle monolayers on mica modified by poly(allylamine hydrochloride) were produced under diffusion-controlled transport. Monolayer coverage, quantitatively determined by AFM and SEM, was regulated within broad limits by adjusting the nanoparticle deposition time. This allowed one to uniquely express the zeta potential of silver monolayers, determined by the in situ streaming potential measurements, in terms of particle coverage. Such dependencies obtained for various ionic strengths and pH, were successfully interpreted in terms of the 3D electrokinetic model. A universal calibrating graph was produced in this way, enabling one to determine silver monolayer coverage from the measured value of the streaming potential. Our experimental data prove that it is feasible to produce uniform and stable silver particle monolayers of well-controlled coverage and defined electrokinetic properties.

Experimental Validation of the Electrokinetic Theory and Development of Seismoelectric Interferometry by Cross-Correlation

Directory of Open Access Journals (Sweden)

F. C. Schoemaker

2012-01-01

Full Text Available We experimentally validate a relatively recent electrokinetic formulation of the streaming potential (SP coefficient as developed by Pride (1994. The start of our investigation focuses on the streaming potential coefficient, which gives rise to the coupling of mechanical and electromagnetic fields. It is found that the theoretical amplitude values of this dynamic SP coefficient are in good agreement with the normalized experimental results over a wide frequency range, assuming no frequency dependence of the bulk conductivity. By adopting the full set of electrokinetic equations, a full-waveform wave propagation model is formulated. We compare the model predictions, neglecting the interface response and modeling only the coseismic fields, with laboratory measurements of a seismic wave of frequency 500 kHz that generates electromagnetic signals. Agreement is observed between measurement and electrokinetic theory regarding the coseismic electric field. The governing equations are subsequently adopted to study the applicability of seismoelectric interferometry. It is shown that seismic sources at a single boundary location are sufficient to retrieve the 1D seismoelectric responses, both for the coseismic and interface components, in a layered model.

Electrokinetic motion of a rectangular nanoparticle in a nanochannel

Energy Technology Data Exchange (ETDEWEB)

Movahed, Saeid; Li Dongqing, E-mail: dongqing@mme.uwaterloo.ca [University of Waterloo, Department of Mechanical and Mechatronics Engineering (Canada)

2012-08-15

This article presents a theoretical study of electrokinetic motion of a negatively charged cubic nanoparticle in a three-dimensional nanochannel with a circular cross-section. Effects of the electrophoretic and the hydrodynamic forces on the nanoparticle motion are examined. Because of the large applied electric field over the nanochannel, the impact of the Brownian force is negligible in comparison with the electrophoretic and the hydrodynamic forces. The conventional theories of electrokinetics such as the Poisson-Boltzmann equation and the Helmholtz-Smoluchowski slip velocity approach are no longer applicable in the small nanochannels. In this study, and at each time step, first, a set of highly coupled partial differential equations including the Poisson-Nernst-Plank equation, the Navier-Stokes equations, and the continuity equation was solved to find the electric potential, ionic concentration field, and the flow field around the nanoparticle. Then, the electrophoretic and hydrodynamic forces acting on the negatively charged nanoparticle were determined. Following that, the Newton second law was utilized to find the velocity of the nanoparticle. Using this model, effects of surface electric charge of the nanochannel, bulk ionic concentration, the size of the nanoparticle, and the radius of the nanochannel on the nanoparticle motion were investigated. Increasing the bulk ionic concentration or the surface charge of the nanochannel will increase the electroosmotic flow, and hence affect the particle's motion. It was also shown that, unlike microchannels with thin EDL, the change in nanochannel size will change the EDL field and the ionic concentration field in the nanochannel, affecting the particle's motion. If the nanochannel size is fixed, a larger particle will move faster than a smaller particle under the same conditions.

Electrokinetic motion of a rectangular nanoparticle in a nanochannel

International Nuclear Information System (INIS)

Movahed, Saeid; Li Dongqing

2012-01-01

This article presents a theoretical study of electrokinetic motion of a negatively charged cubic nanoparticle in a three-dimensional nanochannel with a circular cross-section. Effects of the electrophoretic and the hydrodynamic forces on the nanoparticle motion are examined. Because of the large applied electric field over the nanochannel, the impact of the Brownian force is negligible in comparison with the electrophoretic and the hydrodynamic forces. The conventional theories of electrokinetics such as the Poisson–Boltzmann equation and the Helmholtz–Smoluchowski slip velocity approach are no longer applicable in the small nanochannels. In this study, and at each time step, first, a set of highly coupled partial differential equations including the Poisson–Nernst–Plank equation, the Navier–Stokes equations, and the continuity equation was solved to find the electric potential, ionic concentration field, and the flow field around the nanoparticle. Then, the electrophoretic and hydrodynamic forces acting on the negatively charged nanoparticle were determined. Following that, the Newton second law was utilized to find the velocity of the nanoparticle. Using this model, effects of surface electric charge of the nanochannel, bulk ionic concentration, the size of the nanoparticle, and the radius of the nanochannel on the nanoparticle motion were investigated. Increasing the bulk ionic concentration or the surface charge of the nanochannel will increase the electroosmotic flow, and hence affect the particle’s motion. It was also shown that, unlike microchannels with thin EDL, the change in nanochannel size will change the EDL field and the ionic concentration field in the nanochannel, affecting the particle’s motion. If the nanochannel size is fixed, a larger particle will move faster than a smaller particle under the same conditions.

A Hydromechanic-Electrokinetic Model for CO2 Sequestration in Geological Formations

NARCIS (Netherlands)

Al-Khoury, R.I.N.; Talebian, M.; Sluys, L.J.

2013-01-01

In this contribution, a finite element model for simulating coupled hydromechanic and electrokinetic flow in a multiphase domain is outlined. The model describes CO2 flow in a deformed, unsaturated geological formation and its associated streaming potential flow. The governing field equations are

Electrokinetic properties and conductance relaxation of polystyrene and silver iodide plugs

NARCIS (Netherlands)

Hoven, van den J.J.

1984-01-01

This thesis describes an experimental study on the electrokinetic and electrical properties of concentrated polystyrene and silver iodide dispersions. The purpose of the study is to obtain information on the structure of the electrical double layer at the solid-liquid interface. Special

Bulk conductivity of soft surface layers : experimental measurement and electrokinetic implications

NARCIS (Netherlands)

Yezek, L.P.

2005-01-01

Conductivity measurements were carried out on a family of polyacrylamide-co-sodium acrylate gels cross-linked with N,N¿ -methylenebisacrylamide in a homemade electrokinetic cell. The conductivity data allowed the equilibrium Donnan potential difference between the bulk gel and the bulk electrolyte

Faradaic double layer depolarization in electrokinetics: Onsager relations and substrate limitations

NARCIS (Netherlands)

Leeuwen, van H.P.; Duval, J.F.L.

2007-01-01

More often than not, the measurement of interfacial potentials by means of electrokinetic techniques is affected by interfering processes that may relax or even annihilate their primary response function. Among these processes are faradaic ones, provided that the substrate is sufficiently conducting

Electrokinetic Treatment for Model Caissons with Increasing Dimensions

Directory of Open Access Journals (Sweden)

Eltayeb Mohamedelhassan

2012-01-01

Full Text Available Electrokinetic treatment has been known in geotechnical engineering for over six decades, yet, the technique is rarely used. This stems from the absence of design guidelines and specifications for electrokinetic treatment systems. An important issue that need to be investigated and understood in order to devise guidelines from experimental results is the effect of the foundation element size on the outcome of the treatment. Also important is determining the optimum distance between the electrodes and estimating the energy consumption prior to treatment. This experimental study is a preliminary step in understanding some of the issues critical for the guidelines and specifications. Four model caissons with surface areas between 16000 and 128000 mm2 were embedded in soft clayey soil under water and treated for 168 hr with a dc voltage of 6 V. From the results, a distance between the anode (model caisson and the cathode equal 0.25 times the outside diameter of the model caisson was identified as optimum. Relationships between the surface area and axial capacity of the model caisson and the surface area and energy consumption were presented. The equations can be used to preliminary estimate the load capacity and the energy consumption for full-scale applications.

Separation Of N-Nitrosamines By Micellar Electrokinetic Chromatography

International Nuclear Information System (INIS)

Nur Amira Md Ali; Mohd Marsin Sanagi; Wan Aini Wan Ibrahim

2014-01-01

A simple and rapid micellar electrokinetic chromatography (MEKC) method was developed for separation of three selected N-Nitrosamines namely N-nitrosodipropylamine (NDPA), N-nitrosodibutylamine (NDBA) and N-nitrosodiphenylamine (NDPhA). The effects of composition of the buffer and its pH, concentration of surfactants on the separation and migration times of nitrosamines were investigated. The instrumental variables affecting sensitivity and resolution such as power supply and injection mode were carefully optimized. The best separation was achieved using 40 mM sodium dodecyl sulfate (SDS) as a surfactant in 10 mM phosphate buffer (pH 8.0) at a temperature of 25 degree Celsius, applied voltage of 29 kV, wavelength of 230 nm and electrokinetic injection of 9 s at 5 kV within 10 min analysis time. Excellent linearity was obtained in the concentration range of 2 to 100 μg/ mL with coefficients of determination, r 2 ≥0.979. This method showed good reproducibility with relative standard deviation (RSDs) value ranging from 2.46 % to 6.61 %. The limits of detection (LOD) and limits of quantification (LOQ) ranged from 0.16 to 0.43 μg/ mL and 0.54 to 1.44 μg/mL respectively. (author)

Steady electrodiffusion in hydrogel-colloid composites: macroscale properties from microscale electrokinetics

Directory of Open Access Journals (Sweden)

Reghan J. Hill

2010-03-01

Full Text Available A rigorous microscale electrokinetic model for hydrogel-colloid composites is adopted to compute macroscale profiles of electrolyte concentration, electrostatic potential, and hydrostatic pressure across membranes that separate electrolytes with different concentrations. The membranes are uncharged polymeric hydrogels in which charged spherical colloidal particles are immobilized and randomly dispersed with a low solid volume fraction. Bulk membrane characteristics and performance are calculated from a continuum microscale electrokinetic model (Hill 2006b, c. The computations undertaken in this paper quantify the streaming and membrane potentials. For the membrane potential, increasing the volume fraction of negatively charged inclusions decreases the differential electrostatic potential across the membrane under conditions where there is zero convective flow and zero electrical current. With low electrolyte concentration and highly charged nanoparticles, the membrane potential is very sensitive to the particle volume fraction. Accordingly, the membrane potential - and changes brought about by the inclusion size, charge and concentration - could be a useful experimental diagnostic to complement more recent applications of the microscale electrokinetic model for electrical microrheology and electroacoustics (Hill and Ostoja-Starzewski 2008, Wang and Hill 2008.Um modelo eletrocinético rigoroso para compósitos formados por um hidrogel e um colóide é adotado para computar os perfis macroscópicos de concentração eletrolítica, potencial eletrostático e pressão hidrostática através de uma membrana que separa soluções com diferentes concentrações eletrolíticas. A membrana é composta por um hidrogel polimérico sem carga elétrica onde partículas esféricas são imobilizadas e dispersas aleatoriamente com baixa fração de volume do sólido. As características da membrana e a sua performance são calculadas a partir de um modelo

SANDIA NATIONAL LABORATORIES IN SITU ELECTROKINETIC EXTRACTION TECHNOLOGY; INNOVATIVE TECHNOLOGY EVALUATION REPORT

Science.gov (United States)

As a part of the Superfund Innovative Technology Evaluation (SITE) Program, the U.S. Environmental Protection Agency evaluated the In-Situ Electrokinetic Extraction (ISEE) system at Sandia National Laboratories, Albuquerque, New Mexico.The SITE demonstration results show ...

Self-assembled silver nanoparticles monolayers on mica-AFM, SEM, and electrokinetic characteristics.

Science.gov (United States)

Oćwieja, Magdalena; Morga, Maria; Adamczyk, Zbigniew

2013-03-01

A monodisperse silver particle suspension was produced by a chemical reduction method in an aqueous medium using sodium citrate. The average particle size determined by dynamic light scattering (DLS), transmission electron microscopy (TEM), and atomic force microscopy (AFM) was 28.5 nm. The DLS measurements confirmed that the suspension was stable for the ionic strength up to 3 × 10 -2  M NaCl. The electrophoretic mobility measurements revealed that the electrokinetic charge of particles was negative for pH range 3-10, assuming -50  e for pH = 9 and 0.01 M NaCl. Using the suspension, silver particle monolayers on mica modified by poly(allylamine hydrochloride) were produced under diffusion-controlled transport. Monolayer coverage, quantitatively determined by AFM and SEM, was regulated within broad limits by adjusting the nanoparticle deposition time. This allowed one to uniquely express the zeta potential of silver monolayers, determined by the in situ streaming potential measurements, in terms of particle coverage. Such dependencies obtained for various ionic strengths and pH, were successfully interpreted in terms of the 3D electrokinetic model. A universal calibrating graph was produced in this way, enabling one to determine silver monolayer coverage from the measured value of the streaming potential. Our experimental data prove that it is feasible to produce uniform and stable silver particle monolayers of well-controlled coverage and defined electrokinetic properties.

Determination of patulin in commercial apple juice by micellar electrokinetic chromatography.

Science.gov (United States)

Murillo, M; González-Peñas, E; Amézqueta, S

2008-01-01

A novel and validated micellar electrokinetic capillary chromatography (MEKC) method using ultraviolet detection (UV) has been applied to the quantitative analysis of patulin (PAT) in commercial apple juice. Patulin was extracted from samples with an ethylacetate solution. The micellar electrokinetic capillary chromatography (MECK) parameters studied for method optimization were buffer composition, voltage, temperature, and a separation between PAT and 5-hydroxymethylfurfural (HMF) (main interference in apple juice PAT analysis) peaks until reaching baseline. The method passes a series of validation tests including selectivity, linearity, limit of detection and quantification (0.7 and 2.5 microgL(-1), respectively), precision (within and between-day variability) and recovery (80.2% RSD=4%), accuracy, and robustness. This method was successfully applied to the measurement of 20 apple juice samples obtained from different supermarkets. One hundred percent of the samples were contaminated with a level greater than the limit of detection, with mean and median values of 41.3 and 35.7 microgL(-1), respectively.

Electrokinetics in Earth Sciences: A Tutorial

Directory of Open Access Journals (Sweden)

L. Jouniaux

2012-01-01

in porous media, to be included in the special issue “Electrokinetics in Earth Sciences” of International Journal of Geophysics. We describe the methodology used for self-potential (SP and for seismoelectromagnetic measurements, for both field and laboratory experiments and for modelling. We give a large bibliography on the studies performed in hydrology to detect at distance the water flow, to deduce the thickness of the aquifer and to predict the hydraulic conductivity. The observation of SP has also been proposed to detect fractures in boreholes, to follow the hydraulic fracturing, and to predict the earthquakes. Moreover, we detail the studies on geothermal applications.

Reversible electrokinetic adsorption barriers for the removal of atrazine and oxyfluorfen from spiked soils.

Science.gov (United States)

Vieira Dos Santos, E; Sáez, C; Cañizares, P; Martínez-Huitle, C A; Rodrigo, M A

2017-01-15

This study demonstrates the application of reversible electrokinetic adsorption barrier (REKAB) technology to soils spiked with low-solubility pollutants. A permeable reactive barrier (PRB) of granular activated carbon (GAC) was placed between the anode and cathode of an electrokinetic (EK) soil remediation bench-scale setup with the aim of enhancing the removal of two low-solubility herbicides (atrazine and oxyfluorfen) using a surfactant solution (sodium dodecyl sulfate) as the flushing fluid. This innovative study focused on evaluating the interaction between the EK system and the GAC-PRB, attempting to obtain insights into the primary mechanisms involved. The obtained results highlighted the successful treatment of atrazine and oxyfluorfen in contaminated soils. The results obtained from the tests after 15days of treatment were compared with those obtained using the more conventional electrokinetic soil flushing (EKSF) technology, and very important differences were observed. Although both technologies are efficient for removing the herbicides from soils, REKAB outperforms EKSF. After the 15-day treatment tests, only approximately 10% of atrazine and oxyfluorfen remained in the soil, and adsorption onto the GAC bed was an important removal mechanism (15-17% of herbicide retained). The evaporation loses in REKAB were lower than those obtained in EKSF (45-50% compared to 60-65%). Copyright © 2016 Elsevier B.V. All rights reserved.

Preliminary tests of an electrokinetic barrier to prevent heavy metal pollution of soils

International Nuclear Information System (INIS)

Lynch, R.J.; Muntoni, A.; Ruggeri, R.; Winfield, K.C.

2007-01-01

Sardinia has to deal with significant environmental problems related to heavy-metal contamination, mainly located at its abandoned mining districts. In particular, acid mine drainage management and groundwater pollution are typical problems associated with mining activities which constitute a serious threat to human health. To prevent contaminant spread over the adjacent environment, it is of great interest to consider using an electric field as a containment fence to counteract pollutant transport. In this application, contaminant transport due to a hydraulic gradient driving force is prevented by the combined effect of electro-osmosis and electro-migration. Although there are other alternative containment technologies, the electrokinetic fence offers many advantages, as it is easy to operate, there is a minimal exposure to the operating personnel and it is likely to be effective for a wide range of contaminants. In this work, both one-dimensional (1D) and two-dimensional (2D) tests have been carried out. In the 1D tests, the efficiency of an electrokinetic barrier to prevent cadmium from polluting an uncontaminated sample was investigated; soil pH, metal concentration and current intensity have been monitored; results indicate that the barrier can prevent or significantly reduce heavy-metal contamination from spreading against a hydraulic gradient of 7. In 2D tests, two rows of electrodes inserted in a horizontally flat soil tank were used to generate an electric field. It was found that an electric field of 125 V m -1 was sufficient to prevent significant copper incursion from a contaminant flow under a hydraulic gradient of 1.3

Electrokinetic remediation of a copper contaminated clay: 2-D experiments

Energy Technology Data Exchange (ETDEWEB)

Rodriguez Maroto, J.M.; Garcia Delgado, R.A.; Gomez Lahoz, C.; Garcia Herruzo, F. [Dept. de Ingenieria Quimica, Univ. de Malaga (Spain); Vereda Alonso, C. [Dept. de Ingenieria Quimica, Univ. de Malaga (Spain)]|[Inst. for Geologi and Geoteknik, Danmarks Tekniske Univ., Lyngby (Denmark)

2001-07-01

The in-situ electrokinetic soil remediation technique was used to clean-up a commercial standard kaolin that had been contaminated with copper. A number of experiments were carried out at a lab scale with the purpose of testing the performance of this technique in a 2 dimensional arrangement and establishing the base for future studies on the distribution of electrodes. (orig.)

Dual cloud point extraction coupled with hydrodynamic-electrokinetic two-step injection followed by micellar electrokinetic chromatography for simultaneous determination of trace phenolic estrogens in water samples.

Science.gov (United States)

Wen, Yingying; Li, Jinhua; Liu, Junshen; Lu, Wenhui; Ma, Jiping; Chen, Lingxin

2013-07-01

A dual cloud point extraction (dCPE) off-line enrichment procedure coupled with a hydrodynamic-electrokinetic two-step injection online enrichment technique was successfully developed for simultaneous preconcentration of trace phenolic estrogens (hexestrol, dienestrol, and diethylstilbestrol) in water samples followed by micellar electrokinetic chromatography (MEKC) analysis. Several parameters affecting the extraction and online injection conditions were optimized. Under optimal dCPE-two-step injection-MEKC conditions, detection limits of 7.9-8.9 ng/mL and good linearity in the range from 0.05 to 5 μg/mL with correlation coefficients R(2) ≥ 0.9990 were achieved. Satisfactory recoveries ranging from 83 to 108% were obtained with lake and tap water spiked at 0.1 and 0.5 μg/mL, respectively, with relative standard deviations (n = 6) of 1.3-3.1%. This method was demonstrated to be convenient, rapid, cost-effective, and environmentally benign, and could be used as an alternative to existing methods for analyzing trace residues of phenolic estrogens in water samples.

Washing enhanced electrokinetic remediation for removal cadmium from real contaminated soil

International Nuclear Information System (INIS)

Giannis, Apostolos; Gidarakos, Evangelos

2005-01-01

The main objective of this study is to evaluate the combination of electrokinetic remediation and soil washing technology in order to remove cadmium from contaminated soil. This paper presents the results of an experimental research undertaken to evaluate different washing and purging solutions to enhance the removal of cadmium from a real contaminated soil during electrokinetic remediation. Two different experimental modules were applied in the laboratory. Soil was saturated with tap water, while acetic and hydrochloric acids, as well as ethylenediaminetetraacetic acid (EDTA) were used as purging solutions in the first module. Results show that there was a decrease of cadmium concentration near anode, but a significant increase in the middle of the cell, due to the increasing pH. Citric, nitric and acetic acids were used for soil washing and purging solutions in the second module. In this case, an 85% reduction of cadmium concentration was achieved. Therefore, results indicate that soil pH and washing solutions are the most important factors in governing the dissolution and/or desorption of Cd in a soil system under electrical fields

Coupled electrokinetics-adsorption technique for simultaneous removal of heavy metals and organics from saline-sodic soil.

Science.gov (United States)

Lukman, Salihu; Essa, Mohammed Hussain; Mu'azu, Nuhu Dalhat; Bukhari, Alaadin

2013-01-01

In situ remediation technologies for contaminated soils are faced with significant technical challenges when the contaminated soil has low permeability. Popular traditional technologies are rendered ineffective due to the difficulty encountered in accessing the contaminants as well as when employed in settings where the soil contains mixed contaminants such as petroleum hydrocarbons, heavy metals, and polar organics. In this study, an integrated in situ remediation technique that couples electrokinetics with adsorption, using locally produced granular activated carbon from date palm pits in the treatment zones that are installed directly to bracket the contaminated soils at bench-scale, is investigated. Natural saline-sodic soil, spiked with contaminant mixture (kerosene, phenol, Cr, Cd, Cu, Zn, Pb, and Hg), was used in this study to investigate the efficiency of contaminant removal. For the 21-day period of continuous electrokinetics-adsorption experimental run, efficiency for the removal of Zn, Pb, Cu, Cd, Cr, Hg, phenol, and kerosene was found to reach 26.8, 55.8, 41.0, 34.4, 75.9, 92.49, 100.0, and 49.8%, respectively. The results obtained suggest that integrating adsorption into electrokinetic technology is a promising solution for removal of contaminant mixture from saline-sodic soils.

Influence of the Chemical Interactions on the Removal Rate of Different Salts in Electrokinetic Desalination Processes

DEFF Research Database (Denmark)

Paz-Garcia, Juan Manuel; Johannesson, Björn; Ottosen, Lisbeth M.

2011-01-01

Electrokinetic desalination techniques have been successfully applied for the prevention of salt-induced deterioration problems of masonry and other construction materials. A mathematical model for electrochemical desalination treatments is described, based on the Poisson-Nernst-Planck system...... of equations and accounting for the chemical interactions between the species in the pore solution and the solid matrix. Due to their high abundance in the natural environment, chlorides, nitrates and sulfates are considered the main ions responsible to the salt decay processes in buildings materials...

A laboratory feasibility study on a new electrokinetic nutrient injection pattern and bioremediation of phenanthrene in a clayey soil

International Nuclear Information System (INIS)

Xu Wei; Wang Cuiping; Liu Haibin; Zhang Zhiyuan; Sun Hongwen

2010-01-01

Electrokinetic (EK) injection has recently been proposed to supply nutrients and electron acceptors in bioremediation of low permeable soils. However, effective pH control and uniform injection of inorganic ions have yet to be developed. The present study investigated a new EK injection pattern, which combined electrolyte circulation and electrode polarity reversal on a clayey soil. Soil pH could be controlled ranging from 7.0 to 7.6 by circulating the mixed electrolyte at a suitable rate (800 mL/h in this study) without any buffer. Ammonium and nitrate ions were distributed more uniformly in soil by electrode polarity reversal. The developed electrokinetic injection technology was applied primarily in bioremediation of phenanthrene contaminated soil. Over 80% of the initial 200 mg/kg phenanthrene in soil could be removed in 20 d, and greater phenanthrene removal was achieved using electrode polarity reversal. Hence, the present study provides a promising electrokinetic injection technology for bioremediation of contaminated soils.

Use of solar cell in electrokinetic remediation of cadmium-contaminated soil.

Science.gov (United States)

Yuan, Songhu; Zheng, Zhonghua; Chen, Jing; Lu, Xiaohua

2009-03-15

This preliminary study used a solar cell, instead of direct current (DC) power supply, to generate electric field for electrokinetic (EK) remediation of cadmium-contaminated soil. Three EK tests were conducted and compared; one was conducted on a cloudy and rainy day with solar cell, one was conducted on a sunny day with solar cell and another was conducted periodically with DC power supply. It was found that the output potential of solar cell depended on daytime and was influenced by weather conditions; the applied potential in soil was affected by the output potential and weather conditions, and the current achieved by solar cell was comparable with that achieved by DC power supply. Solar cell could be used to drive the electromigration of cadmium in contaminated soil, and removal efficiency achieved by solar cell was comparable with that achieved by DC power supply. Compared with traditional DC power supply, using solar cell as power supply for EK remediation can greatly reduce energy expenditure. This study provided an alternative to improve the EK soil remediation and expanded the use of solar cell in environmental remediation.

Use of solar cell in electrokinetic remediation of cadmium-contaminated soil

International Nuclear Information System (INIS)

Yuan Songhu; Zheng Zhonghua; Chen Jing; Lu Xiaohua

2009-01-01

This preliminary study used a solar cell, instead of direct current (DC) power supply, to generate electric field for electrokinetic (EK) remediation of cadmium-contaminated soil. Three EK tests were conducted and compared; one was conducted on a cloudy and rainy day with solar cell, one was conducted on a sunny day with solar cell and another was conducted periodically with DC power supply. It was found that the output potential of solar cell depended on daytime and was influenced by weather conditions; the applied potential in soil was affected by the output potential and weather conditions, and the current achieved by solar cell was comparable with that achieved by DC power supply. Solar cell could be used to drive the electromigration of cadmium in contaminated soil, and removal efficiency achieved by solar cell was comparable with that achieved by DC power supply. Compared with traditional DC power supply, using solar cell as power supply for EK remediation can greatly reduce energy expenditure. This study provided an alternative to improve the EK soil remediation and expanded the use of solar cell in environmental remediation

Electrokinetic remediation - a new process for in-situ remediation of polluted land used as construction terrain; Elektrokinetische Bodensanierung - Ein neues Verfahren fuer die in-situ Sanierung bebauter Altlaststandorte

Energy Technology Data Exchange (ETDEWEB)

Haus, R. [Karlsruhe Univ. (T.H.) (Germany). Lehrstuhl fuer Angewandte Geologie

1998-12-31

Electrokinetic Remediation is a coming up technology for the clean up of contaminated sites based on the electrokinetic phenomena in fine grained sediments. The following investigations offer theoretical and experimental consideration about the dependence of electrokinetic remediation techniques on the clay mineralogical composition of various clays. Finally, laboratory tests on the electroosmotic remediation of a chromate contaminated loess loam are presented. Different voltages applied led to important changes in the direction of chromate transport. When using low voltage (1 V) chromate transport was in the direction of water flow, and an increase of chromate in the effluent of the cathode could be measured. In contrast the application of high voltages up to 30 V changed the transport mechanism and high concentrations of chromate chould be detected in the anode reservoir. The results show that the clay mineral composition and the applied electric field controls the electroosmotic permeability, removal efficiency as well as the transport mechanism of the electrokinetic remediation technology in fine grained sediments. (orig.) [Deutsch] Elektrokinetische Verfahren werden in der Geotechnik zur Entwaesserung, Boeschungsstabilisierung und Bodenverbesserung von bindigen Sedimenten eingesetzt. Unter dem sanierungstechnischen Aspekt von kontaminierten Altlaststandorten ermoeglichen elektrokinetische Prozesse erstmals eine gezielte Mobilisierung von Schadstoffen (Schwermetalle, organische Verbindungen) auch in feinkoernigen Gesteinen. Entscheidend ist hierbei die Moeglichkeit eines in situ-Einsatzes unter Vermeidung des Bodenaushubes. Die vorliegenden Untersuchungen vertiefen in theoretischen und versuchstechnischen Betrachtungen die Abhaengigkeit elektrokinetischer Sanierungsverfahren von der tonmineralogischen Zusammensetzung bindiger Gesteine. Oberflaechenladung und Oberflaechenpotential ausgewaehlter Tonminerale werden quantifiziert und den Ergebnissen aus

Effects of triethyl phosphate and nitrate on electrokinetically enhanced biodegradation of diesel in low permeability soils.

Science.gov (United States)

Lee, G T; Ro, H M; Lee, S M

2007-08-01

Bench-scale experiments for electrokinetically enhanced bioremediation of diesel in low permeability soils were conducted. An electrokinetic reactor (ER) was filled with kaolin that was artificially contaminated with diesel at a level of 2500 mg kg(-1). A constant voltage gradient of 1.0 V cm(-1) was applied. In phosphorus transport experiments, KH2PO4 was not distributed homogeneously along the ER, and most of the transported phosphorus was converted to water-insoluble aluminum phosphate after 12 days of electrokinetic (EK) operation. However, the advancing P front of triethyl phosphate (TEP) progressed with time and resulted in uniform P distribution. The treatments employed in the electrokinetically enhanced bioremediation of diesel were control (no addition of nitrogen and phosphorus), NP (KNO3+ KH2PO4), NT (KNO3+ TEP), UP (urea+ KH2PO4), and UT (urea+TEP). Analysis of effluent collected during the first 12 days of EK operation showed that diesel was not removed from the kaolin. After nutrient delivery, using the EK operation, the ER was transferred into an incubator for the biodegradation process. After 60 days of biodegradation, the concentrations of diesel in the kaolin for the NP, NT, UP, UT, and control treatments were 1356, 1002, 1658, 1612, and 2003 mg kg(-1), respectively. The ratio of biodegraded diesel concentration to initial concentration (2465 mg kg(-1)) in NP, NT, UP, UT, and control were 45.0%, 59.4%, 32.7%, 34.6%, and 18.7%, respectively. This result showed that TEP, treated along with NO3-, was most effective for the biodegradation of diesel. TEP was delivered more efficiently to the target zones and with less phosphorus loss than KH2PO4. However, this facilitated phosphorus delivery was effective in biodegrading diesel under anaerobic conditions only when electron acceptors, such as NO3-, were present.

Microchannel electrokinetics of charged analytes in buffered solutions near floating electrodes

DEFF Research Database (Denmark)

Andersen, Mathias Bækbo; Wolfcale, Trevor; Gregersen, Misha Marie

to accurately predict such behavior in these flow regimes. Experimentally, using conventional fluorescence microscopy, we investigated the concentration gradient (as well as the associated electroosmosis, induced-charge electro-osmosis, and electrophoresis) of the charged analyte near the floating electrode......We present both experimental and numerical studies of nonlinear electrokinetic flow of buffered solutions seeded with dilute analytes in a straight microchannel (0.6 μm high, 250 μm wide, and 9000 μm long) with a 0.15 μm high 60 μm wide electrode situated at the bottom center of the channel...... as a function of analyte (1 to 10 μM fluorescein and bodipy) and buffer (1 to 10 mM borate and posphate) concentrations and an externally applied voltage drop (50 to 100 V) along the channel. We have implemented a nonlinear continuum kinetics model of the system involving the electric potential, the buffer flow...

Coupled Electrokinetics-Adsorption Technique for Simultaneous Removal of Heavy Metals and Organics from Saline-Sodic Soil

Science.gov (United States)

Lukman, Salihu; Essa, Mohammed Hussain; Mu'azu, Nuhu Dalhat; Bukhari, Alaadin

2013-01-01

In situ remediation technologies for contaminated soils are faced with significant technical challenges when the contaminated soil has low permeability. Popular traditional technologies are rendered ineffective due to the difficulty encountered in accessing the contaminants as well as when employed in settings where the soil contains mixed contaminants such as petroleum hydrocarbons, heavy metals, and polar organics. In this study, an integrated in situ remediation technique that couples electrokinetics with adsorption, using locally produced granular activated carbon from date palm pits in the treatment zones that are installed directly to bracket the contaminated soils at bench-scale, is investigated. Natural saline-sodic soil, spiked with contaminant mixture (kerosene, phenol, Cr, Cd, Cu, Zn, Pb, and Hg), was used in this study to investigate the efficiency of contaminant removal. For the 21-day period of continuous electrokinetics-adsorption experimental run, efficiency for the removal of Zn, Pb, Cu, Cd, Cr, Hg, phenol, and kerosene was found to reach 26.8, 55.8, 41.0, 34.4, 75.9, 92.49, 100.0, and 49.8%, respectively. The results obtained suggest that integrating adsorption into electrokinetic technology is a promising solution for removal of contaminant mixture from saline-sodic soils. PMID:24235885

Coupled Electrokinetics-Adsorption Technique for Simultaneous Removal of Heavy Metals and Organics from Saline-Sodic Soil

Directory of Open Access Journals (Sweden)

Salihu Lukman

2013-01-01

Full Text Available In situ remediation technologies for contaminated soils are faced with significant technical challenges when the contaminated soil has low permeability. Popular traditional technologies are rendered ineffective due to the difficulty encountered in accessing the contaminants as well as when employed in settings where the soil contains mixed contaminants such as petroleum hydrocarbons, heavy metals, and polar organics. In this study, an integrated in situ remediation technique that couples electrokinetics with adsorption, using locally produced granular activated carbon from date palm pits in the treatment zones that are installed directly to bracket the contaminated soils at bench-scale, is investigated. Natural saline-sodic soil, spiked with contaminant mixture (kerosene, phenol, Cr, Cd, Cu, Zn, Pb, and Hg, was used in this study to investigate the efficiency of contaminant removal. For the 21-day period of continuous electrokinetics-adsorption experimental run, efficiency for the removal of Zn, Pb, Cu, Cd, Cr, Hg, phenol, and kerosene was found to reach 26.8, 55.8, 41.0, 34.4, 75.9, 92.49, 100.0, and 49.8%, respectively. The results obtained suggest that integrating adsorption into electrokinetic technology is a promising solution for removal of contaminant mixture from saline-sodic soils.

Selecting enhancing solutions for electrokinetic remediation of dredged sediments polluted with fuel.

Science.gov (United States)

Rozas, F; Castellote, M

2015-03-15

In this paper a procedure for selecting the enhancing solutions in electrokinetic remediation experiments is proposed. For this purpose, dredged marine sediment was contaminated with fuel, and a total of 22 different experimental conditions were tested, analysing the influence of different enhancing solutions by using three commercial non-ionic surfactants, one bio-surfactant, one chelating agent, and one weak acid. Characterisation, microelectrophoretic and electrokinetic remediation trials were carried out. The results are explained on the basis of the interactions between the fuel, the enhancing electrolytes and the matrix. For one specific system, the electrophoretic zeta potential, (ζ), of the contaminated matrix in the solution was found to be related to the electroosmotic averaged ζ in the experiment and not to the efficiency in the extraction. This later was correlated to a parameter accounting for both contributions, the contaminant and the enhancing solution, calculated on the basis of differences in the electrophoretic ζ in different conditions which has allowed to propose a methodology for selection of enhancing solutions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Microemulsion Electrokinetic Chromatography.

Science.gov (United States)

Buchberger, Wolfgang

2016-01-01

Microemulsion electrokinetic chromatography (MEEKC) is a special mode of capillary electrophoresis employing a microemulsion as carrier electrolyte. Analytes may partition between the aqueous phase of the microemulsion and its oil droplets which act as a pseudostationary phase. The technique is well suited for the separation of neutral species, in which case charged oil droplets (obtained by addition of an anionic or cationic surfactant) are present. A single set of separation parameters may be sufficient for separation of a wide range of analytes belonging to quite different chemical classes. Fine-tuning of resolution and analysis time may be achieved by addition of organic solvents, by changes in the nature of the surfactants (and cosurfactants) used to stabilize the microemulsion, or by various additives that may undergo some additional interactions with the analytes. Besides the separation of neutral analytes (which may be the most important application area of MEEKC), it can also be employed for cationic and/or anionic species. In this chapter, MEEKC conditions are summarized that have proven their reliability for routine analysis. Furthermore, the mechanisms encountered in MEEKC allow an efficient on-capillary preconcentration of analytes, so that the problem of poor concentration sensitivity of ultraviolet absorbance detection is circumvented.

Electrokinetic extraction of surfactants and heavy metals from sewage sludge

International Nuclear Information System (INIS)

Ferri, Violetta; Ferro, Sergio; Martinez-Huitle, Carlos A.; De Battisti, Achille

2009-01-01

Waste management represents a quite serious problem involving aspects of remediation technologies and potential re-utilization in different fields of human activities. Of course, wastes generated in industrial activities deserve more attention because of the nature and amount of xenobiotic components, often difficult to be eliminated. However, also ordinary wastes of urban origin are drawing more and more attention, depending on the concentration of noxious substances like surfactants and some heavy metal, which may eventually require expensive disposal. In the present paper, a research has been carried out on the application of electrokinetic treatments for the abatement of the above xenobiotic components from sewage sludge generated in urban wastewater treatment plants. Experiments were carried out on a laboratory scale, in a 250 mm x 50 mm x 100 mm cell, using 250-300 g of sludge for each test and current densities between 2.4 and 5.7 mA cm -2 . As a general result, quite significant abatements of heavy-metal ions and surfactants were achieved, with relatively low energy consumption

Electrokinetic remediation of anionic contaminants from unsaturated soils

International Nuclear Information System (INIS)

Lindgren, E.R.; Kozak, M.W.; Mattson, E.D.

1992-01-01

Heavy-metal contamination of soil and groundwater is a widespread problem in the DOE weapons complex, and for the nation as a whole. Electrokinetic remediation is one possible technique for in situ removal of such contaminants from unsaturated soils. In previous studies at Sandia National Laboratories, the electromigration of chromate ions and anionic dye ions have been demonstrated. This paper reports on a series of experiments that were conducted to study the effect of moisture content on the electromigration rate of anionic contaminants in unsaturated soil and determine the limiting moisture content for which electromigration occurs

ELECTROKINETIC DENSIFICATION OF COAL FINES IN WASTE PONDS

Energy Technology Data Exchange (ETDEWEB)

E. James Davis

1999-12-18

The objective of this research was to demonstrate that electrokinetics can be used to remove colloidal coal and mineral particles from coal-washing ponds and lakes without the addition of chemical additives such as salts and polymeric flocculants. The specific objectives were: Design and develop a scaleable electrophoresis apparatus to clarify suspensions of colloidal coal and clay particles; Demonstrate the separation process using polluted waste water from the coal-washing facilities at the coal-fired power plants in Centralia, WA; Develop a mathematical model of the process to predict the rate of clarification and the suspension electrical properties needed for scale up.

Salinity effects during immiscible displacement in porous media: electrokinetic stabilization of viscous fingering

Science.gov (United States)

Mirzadeh, Mohammad; Bazant, Martin

2017-11-01

Interfacial instabilities are ubiquitous in Fluid Mechanics and have been one of the main the subjects of pattern formation. However, these instabilities could lead to inefficiencies which are undesired in many applications. For instance, viscous fingering results in residual trapping of oil during secondary recovery when a low-viscosity fluid, e.g. water, is used for injection. In their seminal work, Saffman and Taylor showed that the onset of this instability is controlled by the viscosity ratio of the two fluids. However, other physiochemical processes could enhance or suppress viscous fingering. Here we consider the role of salinity effects on the front stability. Our recent theory suggests that viscous fingering could be controlled, and even suppressed, by appropriately injecting electric currents. However, even in the absence of any external currents, strong electrokinetic coupling (present in small pores when the electric double layers overlap) can reduce viscous fingering by increasing the ``effective viscosity'' of the injected fluid. These findings suggest that it might be possible to improve extraction efficiencies by appropriately controlling the salt concentration of the injected fluid.

Faradaic AC Electrokinetic Flow and Particle Traps

Science.gov (United States)

Ben, Yuxing; Chang, Hsueh-Chia

2004-11-01

Faradaic reaction at higher voltages can produce co-ion polarization at AC electrodes instead of counter-ion polarization due to capacitive charging from the bulk. The Faradaic co-ion polarization also does not screen the external field and hence can produce large net electro-kinetic flows at frequencies lower than the inverse RC time of the double layer. Due to the opposite polarization of capacitve and Faradaic charging, we can reverse the direction of AC flows on electrodes by changing the voltage and frequency. Particles and bacteria are trapped and then dispersed at stagnation lines, at locations predicted by our theory, by using these two flows sequentially. This technique offers a good way to concentrate and detect bacteria.

Electrokinetics of diffuse soft interfaces. III. Interpretation of data on the polyacrylamide/water interface

NARCIS (Netherlands)

Yezek, L.P.; Duval, J.F.L.; Leeuwen, van H.P.

2005-01-01

Streaming potential measurements were carried out on a family of polyacrylamide-co-sodium acrylate gels cross-linked with N,N¿- methylenebisacrylamide in a homemade electrokinetic cell. Measurements of the ionic conductivity within thin films of these gels allowed the equilibrium Donnan potential

Atmospheric pressure photoionization for enhanced compatibility in on-line micellar electrokinetic chromatography-mass spectrometry

NARCIS (Netherlands)

Mol, Roelof; De Jong, Gerhardus J.; Somsen, Govert W.

2005-01-01

Atmospheric pressure photoionization (APPI) is presented as a novel means for the combination of micellar electrokinetic chromatography (MEKC) and mass spectrometry (MS). The on-line coupling is achieved using an adapted sheath flow interface installed on an orthogonal APPI source. Acetone or

Effect of Wetting Agents and Approaching Anodes on Lead Migration in Electrokinetic Soil Remediation

OpenAIRE

Ng, Yee-Sern; Gupta, Bhaskar Sen; Hashim, Mohd Ali

2015-01-01

This is the presentation slides for my conference paper "Effect of Wetting Agents and Approaching Anodes on Lead Migration in Electrokinetic Soil Remediation", which was presented in 5th International Conference on Chemical Engineering and Applications, Taipei on 27 August 2014.

Physicochemical and numerical modeling of electrokinetics in inhomogenous matrices

DEFF Research Database (Denmark)

Paz-Garcia, Juan Manuel

A physicochemical model has been proposed based on the Nernst-Planck-Poisson system. The model includes the transport of water through the porous media, the monitoring of the degree of saturation, the pH value and the porosity throughout the domain; and a comprehensive set of chemical and electrochemical reactions...... is mainly based on a finite elements method for the integration of the transient system of partial differential equations coupled with a Newton-Raphson method for computing chemical equilibrium. During the development of the proposed physicochemical and numerical model, different electrokinetic systems have...

A short tutorial contribution to impedance and AC-electrokinetic characterization and manipulation of cells and media: Are electric methods more versatile than acoustic and laser methods?

Directory of Open Access Journals (Sweden)

Jan Gimsa

2014-11-01

Full Text Available Lab-on-chip systems (LOCs can be used as in vitro systems for cell culture or manipulation in order to analyze or monitor physiological cell parameters. LOCs may combine microfluidic structures with integrated elements such as piezo-transducers, optical tweezers or electrodes for AC-electrokinetic cell and media manipulations. The wide frequency band (<1 kHz to >1 GHz usable for AC-electrokinetic manipulation and characterization permits avoiding electrochemical electrode processes, undesired cell damage, and provides a choice between different polarization effects that permit a high electric contrast between the cells and the external medium as well as the differentiation between cellular subpopulations according to a variety of parameters. It has been shown that structural polarization effects do not only determine the impedance of cell suspensions and the force effects in AC-electrokinetics but can also be used for the manipulation of media with inhomogeneous temperature distributions. This manuscript considers the interrelations of the impedance of suspensions of cells and AC-electrokinetic single cell effects, such as electroorientation, electrodeformation, dielectrophoresis, electrorotation, and travelling wave (TW dielectrophoresis. Unified models have allowed us to derive new characteristic equations for the impedance of a suspension of spherical cells, TW dielectrophoresis, and TW pumping. A critical review of the working principles of electro-osmotic, TW and electrothermal micropumps shows the superiority of the electrothermal pumps. Finally, examples are shown for LOC elements that can be produced as metallic structures on glass chips, which may form the bottom plate for self-sealing microfluidic systems. The structures can be used for cell characterization and manipulation but also to realize micropumps or sensors for pH, metabolites, cell-adhesion, etc.

Electrokinetic remediation of a copper contaminated soil - experiments and 1-D model

Energy Technology Data Exchange (ETDEWEB)

Vereda Alonso, C.; Hansen, H.K. [Inst. for Geologi and Geoteknik, Danmarks Tekniske Univ., Lyngby (Denmark); Gomez Lahoz, C.; Rodriguez Maroto, J.M. [Dept. de Ingenieria Quimica, Univ. de Malaga (Spain)

2001-07-01

In this work, a set of electrokinetic soil remediation experiments has been performed in a column containing a commercial standard kaolin that was previously contaminated with copper. The profile evolution of copper concentration and pH along the soil column was obtained from these experiments. A one-dimensional numerical model has been developed to simulate the experimental results obtained from these experiments. (orig.)

A case of biliary stones and anastomotic biliary stricture after liver transplant treated with the rendez - vous technique and electrokinetic lithotritor

Institute of Scientific and Technical Information of China (English)

Marta Di Pisa; Mario Traina; Roberto Miraglia; Luigi Maruzzelli; Riccardo Volpes; Salvatore Piazza; Angelo Luca; Bruno Gridelli

2008-01-01

The paper studies the combined radiologic and endoscopic approach (rendezvous technique) to the treatment of the biliary complications following liver transplant. The "rendez-vous" technique was used with an electrokinetic lithotripter, in the treatment of a biliary anastomotic stricture with multiple biliary stones in a patient who underwent orthotopic liver transplant. In this patient, endoscopic or percutaneous transhepatic management of the biliary complication failed. The combined approach, percutaneous transhepatic and endoscopic treatment (rendez-vous technique) with the use of an electrokinetic lithotritor, was used to solve the biliary stenosis and to remove the stones.Technical success, defined as disappearance of the biliary stenosis and stone removal, was obtained in just one session, which definitively solved the complications.The combined approach of percutaneous transhepatic and endoscopic (rendez-vous technique) treatment, in association with an electrokinetic lithotritor, is a safe and feasible alternative treatment, especially after the failure of endoscopic and/or percutaneous trans-hepatic isolated procedures.

Control of electrode processes in electrokinetic soil remediation

Energy Technology Data Exchange (ETDEWEB)

Schmid, M.; Marb, C. [Bavarian State Office for Environmental Protection, Waste Technology Centre, Augsburg (Germany)

2001-07-01

Technical control of electrode processes induced by water electrolysis is crucial for the effectiveness of electrokinetic soil remediation. A calculation method for the quantification of electrolysis products is derived and its validity by the consumption of neutralizing agents verified. Steel rods used as sacrificial anodes instead of inert materials cannot counteract the acidification of the anolyte due to the acidic property of Fe-cations released as oxidation products. An an alternative to ordinary porous well materials a tubular cation exchange membrane was used as a cathode well. Thereby the migration of anions stemming from the catholyte neutralisation was hampered and no loss in the electric field strength occured. (orig.)

Chelating agent-assisted electrokinetic removal of cadmium, lead and copper from contaminated soils

International Nuclear Information System (INIS)

Giannis, Apostolos; Nikolaou, Aris; Pentari, Despina; Gidarakos, Evangelos

2009-01-01

An integrated experimental program was conducted to remove Cd, Pb and Cu from contaminated soil. The chelate agents nitrilotriacetic acid (NTA), diethylenetriamine pentaacetic acid (DTPA) and ethyleneglycol tetraacetic acid (EGTA) were used as washing solutions under different pH conditions and concentrations. Results showed that the extraction efficiency for Cd in decreasing order was NTA > EGTA > DTPA, while for Pb and Cu it was DTPA > NTA > EGTA. The use of higher chelate concentrations did not necessarily result in greater extraction efficiency. Electrokinetic remediation was applied by conditioning anolyte-catholyte pH to neutral values in order to avoid any potential alterations to the physicochemical soil properties. The removal efficiency for Cd was 65-95%, for Cu 15-60%, but for Pb was less than 20%. The phytotoxicity of the treated soil showed that the soil samples from the anode section were less phytotoxic than the untreated soil, but the phytotoxicity was increased in the samples from the cathode section. - Cadmium, lead and copper were extracted from contaminated soil by integrated electrokinetic and soil washing studies.

Chelating agent-assisted electrokinetic removal of cadmium, lead and copper from contaminated soils

Energy Technology Data Exchange (ETDEWEB)

Giannis, Apostolos, E-mail: apostolos.giannis@enveng.tuc.g [Laboratory of Toxic and Hazardous Waste Management, Department of Environmental Engineering, Technical University of Crete, Politechnioupolis, Chania 73100 (Greece); Nikolaou, Aris [Laboratory of Toxic and Hazardous Waste Management, Department of Environmental Engineering, Technical University of Crete, Politechnioupolis, Chania 73100 (Greece); Pentari, Despina [Laboratory of Inorganic and Organic Geochemistry and Organic Petrography, Department of Mineral Resources Engineering, Technical University of Crete, Politechnioupolis, Chania 73100 (Greece); Gidarakos, Evangelos, E-mail: gidarako@mred.tuc.g [Laboratory of Toxic and Hazardous Waste Management, Department of Environmental Engineering, Technical University of Crete, Politechnioupolis, Chania 73100 (Greece)

2009-12-15

An integrated experimental program was conducted to remove Cd, Pb and Cu from contaminated soil. The chelate agents nitrilotriacetic acid (NTA), diethylenetriamine pentaacetic acid (DTPA) and ethyleneglycol tetraacetic acid (EGTA) were used as washing solutions under different pH conditions and concentrations. Results showed that the extraction efficiency for Cd in decreasing order was NTA > EGTA > DTPA, while for Pb and Cu it was DTPA > NTA > EGTA. The use of higher chelate concentrations did not necessarily result in greater extraction efficiency. Electrokinetic remediation was applied by conditioning anolyte-catholyte pH to neutral values in order to avoid any potential alterations to the physicochemical soil properties. The removal efficiency for Cd was 65-95%, for Cu 15-60%, but for Pb was less than 20%. The phytotoxicity of the treated soil showed that the soil samples from the anode section were less phytotoxic than the untreated soil, but the phytotoxicity was increased in the samples from the cathode section. - Cadmium, lead and copper were extracted from contaminated soil by integrated electrokinetic and soil washing studies.

Sludge reduction in a small wastewater treatment plant by electro-kinetic disintegration.

Science.gov (United States)

Chiavola, Agostina; Ridolfi, Alessandra; D'Amato, Emilio; Bongirolami, Simona; Cima, Ennio; Sirini, Piero; Gavasci, Renato

2015-01-01

Sludge reduction in a wastewater treatment plant (WWTP) has recently become a key issue for the managing companies, due to the increasing constraints on the disposal alternatives. Therefore, all the solutions proposed with the aim of minimizing sludge production are receiving increasing attention and are tested either at laboratory or full-scale to evaluate their real effectiveness. In the present paper, electro-kinetic disintegration has been applied at full-scale in the recycle loop of the sludge drawn from the secondary settlement tank of a small WWTP for domestic sewage. After the disintegration stage, the treated sludge was returned to the biological reactor. Three different percentages (50, 75 and 100%) of the return sludge flow rate were subjected to disintegration and the effects on the sludge production and the WWTP operation efficiency evaluated. The long-term observations showed that the electro-kinetic disintegration was able to drastically reduce the amount of biological sludge produced by the plant, without affecting its treatment efficiency. The highest reduction was achieved when 100% return sludge flow rate was subjected to the disintegration process. The reduced sludge production gave rise to a considerable net cost saving for the company which manages the plant.

Spatial distribution of mechanical forces and ionic flux in electro-kinetic instability near a permselective membrane

Science.gov (United States)

Magnico, Pierre

2018-01-01

This paper is devoted to the numerical investigation of electro-kinetic instability in a polarization layer next to a cation-exchange membrane. An analysis of some properties of the electro-kinetic instability is followed by a detailed description of the fluid flow structure and of the spatial distribution of the ionic flux. In this aim, the Stokes-Poisson-Nernst-Planck equation set is solved until the Debye length scale. The results show that the potential threshold of the marginal instability and the current density depend on the logarithm of the concentration at the membrane surface. The size of the stable vortices seems to be an increasing function of the potential drop. The fluid motion is induced by the electric force along the maximum concentration in the extended space charge (ESC) region and by the pressure force in the region around the inner edge of the ESC layer. Two spots of kinetic energy are located in the ESC region and between the vortices. The cationic motion, controlled by the electric field and the convection, presents counter-rotating vortices in the stagnation zone located in the fluid ejection region. The anion transport is also characterized by two independent layers which contain counter-rotating vortices. The first one is in contact with the stationary reservoir. In the second layer against the membrane, the convection, and the electric field control, the transversal motion, the Fickian diffusion, and the convection are dominant in the longitudinal direction. Finally, the longitudinal disequilibrium of potential and pressure along the membrane is analyzed.

Integrating Electrokinetic and Bioremediation Process for Treating Oil Contaminated Low Permeability Soil

OpenAIRE

Surya Ramadan Bimastyaji; Jatnika Effendi Agus; Helmy Qomarudin

2018-01-01

Traditional oil mining activities always ignores environmental regulation which may cause contamination in soil and environment. Crude oil contamination in low-permeability soil complicates recovery process because it requires substantial energy for excavating and crushing the soil. Electrokinetic technology can be used as an alternative technology to treat contaminated soil and improve bioremediation process (biostimulation) through transfer of ions and nutrient that support microorganism gr...

Fabrication of Micromixers Utilizing Shedding Effect Induced by Electrokinetic Instability

International Nuclear Information System (INIS)

Fu, L-M; Tai, C-H; Tsai, C-H; Lin, C-H; Lee, C-Y

2006-01-01

This paper proposes a T-shaped micromixer featuring 45 deg. parallelogram barriers within the mixing channel. The proposed device obtains a rapid mixing of two sample fluids by means of the electrokinetic instability induced by shedding effect which is produced as an appropriate intensity of DC electric field of is applied. The proposed device uses a single high-voltage power source to simultaneously drive and mix the sample fluids. The effectiveness of the mixer is characterized experimentally as a function of the applied electrical field intensity and the extent to which the parallelogram barriers obstruct the mixing channel. The experimental results indicate that the mixing performance reaches 91.2% at a cross-section located 2.3 mm downstream of the T-junction when the barriers obstruct four-fifths of the channel width and an electrical field of 300V/cm is applied. The micromixing method presented in this study provides a simple low-cost solution to mixing problems in lab-on-a-chip systems

Evolution of microbial communities during electrokinetic treatment of antibiotic-polluted soil.

Science.gov (United States)

Li, Hongna; Li, Binxu; Zhang, Zhiguo; Zhu, Changxiong; Tian, Yunlong; Ye, Jing

2018-02-01

The evolution of microbial communities during the electrokinetic treatment of antibiotic-polluted soil (EKA) was investigated with chlortetracycline (CTC), oxytetracycline (OTC) and tetracycline (TC) as template antibiotics. The total population of soil microorganisms was less affected during the electrokinetic process, while living anti-CTC, anti-OTC, anti-TC and anti-MIX bacteria were inactivated by 10.48%, 31.37%, 34.76%, and 22.08%, respectively, during the 7-day treatment compared with antibiotic-polluted soil without an electric field (NOE). Accordingly, samples with NOE treatment showed a higher Shannon index than those with EKA treatment, indicating a reduction of the microbial community diversity after electrokinetic processes. The major taxonomic phyla found in the samples of EKA and NOE treatment were Proteobacteria, Bacteroidetes, Firmicutes and Actinobacteria. And the distribution of Actinobacteria, Cyanobacteria, and Chloroflexi was greatly decreased compared with blank soil. In the phylum Proteobacteria, the abundance of Alphaproteobacteria was greatly reduced in the soils supplemented with antibiotics (from 13.40% in blank soil to 6.43-10.16% after treatment); while Betaproteobacteria and Deltaproteobacteria showed a different trend with their abundance increased compared to blank soil, and Gammaproteobacteria remained unchanged for all treatments (2.36-2.78%). The varied trends for different classes indicated that the major bacterial groups changed with the treatments due to their different adaptability to the antibiotics as well as to the electric field. SulI being an exception, the reduction ratio of the observed antibiotic resistance genes (ARGs) including tetC, tetG, tetW, tetM, intI1, and sulII in the 0-2cm soil sampled with EKA versus NOE treatment reached 55.17%, 3.59%, 99.26%, 89.51%, 30.40%, and 27.92%, respectively. Finally, correlation analysis was conducted between antibiotic-resistant bacteria, ARGs and taxonomic bacterial classes. It

Electrokinetic characteristics fused quartz in solutions of 1:1, 2:1 and 3:1 charge electrolytes

International Nuclear Information System (INIS)

Bogdanova, N.F.; Sidorova, M.P.; Ermakova, L.Eh.; Savina, I.A.

1997-01-01

Electrokinetic characteristics of silicon oxide have been studied using a model system - a plane-parallel capillary in chloride solutions containing mono-(H + , Na + , Cs + ), two-(Ba 2+ ) and three-(La 3+ ) charge counterions in a wide range of pH and concentrations. It has been revealed that isoelectric point (IEP) of silicon oxide studied coincides with the one usually quoted in literature and corresponds to pH2 in the absence of specific adsorption. Specific adsorption of cesium ions resulting in IEP displacement to pH 3.3 at the back-ground of 0.1M CsCl solution has been detected. Specific adsorption of lanthanum ions increases with increase in the surface charge, involving appearance of a positive electrokinetic potential range at pH>3.3 at the background of 0.1g-eq/l LaCl 3 solution

Electrokinetic-enhanced bioaugmentation for remediation of chlorinated solvents contaminated clay

International Nuclear Information System (INIS)

Mao, Xuhui; Wang, James; Ciblak, Ali; Cox, Evan E.; Riis, Charlotte; Terkelsen, Mads; Gent, David B.; Alshawabkeh, Akram N.

2012-01-01

Highlights: ► Simultaneous delivery of electron donors and bacteria into low permeability clays. ► Bacteria injection, growth and consequent transformation of contaminants are viable. ► EK injection is more effective than advection-based injection for clay soil. ► Electroosmosis appears to be the driving mechanism for bacteria injection. ► Both EK transport and biodegradation contribute the removal of VOCs in clay. - Abstract: Successful bioremediation of contaminated soils is controlled by the ability to deliver bioremediation additives, such as bacteria and/or nutrients, to the contaminated zone. Because hydraulic advection is not practical for delivery in clays, electrokinetic (EK) injection is an alternative for efficient and uniform delivery of bioremediation additive into low-permeability soil and heterogeneous deposits. EK-enhanced bioaugmentation for remediation of clays contaminated with chlorinated solvents is evaluated. Dehalococcoides (Dhc) bacterial strain and lactate ions are uniformly injected in contaminated clay and complete dechlorination of chlorinated ethene is observed in laboratory experiments. The injected bacteria can survive, grow, and promote effective dechlorination under EK conditions and after EK application. The distribution of Dhc within the clay suggests that electrokinetic transport of Dhc is primarily driven by electroosmosis. In addition to biodegradation due to bioaugmentation of Dhc, an EK-driven transport of chlorinated ethenes is observed in the clay, which accelerates cleanup of chlorinated ethenes from the anode side. Compared with conventional advection-based delivery, EK injection is significantly more effective for establishing microbial reductive dechlorination capacity in low-permeability soils.

ELECTROKINETIC DENSIFICATION OF COAL FINES IN WASTE PONDS

Energy Technology Data Exchange (ETDEWEB)

E. James Davis

1998-05-01

The objective of this research is to demonstrate that electrokinetics can be used to remove colloidal coal and mineral particles from coal-washing ponds and lakes without the addition of chemical additives such as salts and polymeric flocculants. In this experimental and analytical study the authors elucidate the transport processes that control the rate of concentrated colloidal particle removal, demonstrate the process on a laboratory scale, and develop the scale-up laws needed to design commercial-scale processes. The authors are also addressing the fundamental problems associated with particle-particle interactions (electrical and hydrodynamic), the effects of particle concentration on the applied electric field, the electrochemical reactions that occur at the electrodes, and the prediction of power requirements.

Removal of heavy metals from sludge of Sanaru-Lake by electrokinetics

Energy Technology Data Exchange (ETDEWEB)

Seno, T.; Shiba, S.; Hirata, Y. [Dept. of Systems Engineering, Shizuoka Univ., Hamamatsu (Japan)

2001-07-01

Two kinds of experiments were carried out for the removal of heavy metals from soils by electrokinetic technique. One was the removal of lead from kaolinite by using a small-sized test cell. The effect of the kind of purging solutions (such as distilled water, tap water, acetic acid and nitric acid) on removal efficiency was examined. High removal efficiency was obtained for the acetic acid solution. It was found that the controlling pH of solution surrounding cathode had a significant influence on the removal efficiency. The other experiment was the removal of heavy metals from the bottom sludge of Sanaru Lake. Zinc, nickel and copper in the sludge were successfully removed, but lead and chromium were hardly able to remove from the sludge. The simplified one-dimensional mathematical model was proposed. The prediction by the model was qualitatively agreed with the experimental result. (orig.)

Electrokinetic remediation of lead and nickel in land farming soil of petroleum refinery; Remediacao eletrocinetica de chumbo e niquel em solos de landfarming de uma refinaria de petroleo

Energy Technology Data Exchange (ETDEWEB)

Guaracho, Viviane V.; Ponte, Maria Jose J.S.; Adamoski, Luiz Felipe [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil)

2004-07-01

In many areas in the world, the ground has been seriously contaminated, had to practical of inadequate disposal and pollutant industrial activities. This polluted soil becomes a threat to the environment for presenting toxical substances, as the heavy metals. The alternative to solve this threat is a technique of electrokinetic remediation, which has been considered promising because it presents an excellent potential of recovery of places contaminated by heavy metals. This technique consists on the application of a direct current of low intensity through the ground between two or more electrodes. This way, the objective of this work is to evaluate the performance of the electrokinetic remediation for removal of Lead and Nickel, from the ground of land farming from petroleum refineries. The ground will be simulated using contaminated sand with nickel and lead nitrate with concentrations previously established. For a reduction in the experimental costs, one technique of statistical planning will be used. Parameters will be modified as: concentration of ions, applied potential and time. Through the concentration profile it is intended to calculate the coefficient of mass transport in order to get a correlation between the concentration and the flow of the species. Aiming at a economical evaluation of the reactor, the current and the energy consumption efficiencies will be evaluated. (author)

Electrokinetic remediation of heavy metals contaminated kaolin by a CNT-covered polyethylene terephthalate yarn cathode

International Nuclear Information System (INIS)

Yuan, Lizhu; Li, Haiyan; Xu, Xingjian; Zhang, Jing; Wang, Nana; Yu, Hongwen

2016-01-01

In the current study, carbon nanotube (CNT) covered polyethylene terephthalate yarns (PET-CNT) electrode has been investigated as a novel cathode material for the electrokinetic (EK) remediation of multi-metals (Cd, Cu, Ni, Pb, Zn) contaminated kaolin. The results of scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) showed that CNT was successfully covered on the surface of PET. The results obtained from EK process showed that PET-CNT as a cathode obviously elevated electric current and electro-osmotic flow (EOF), significantly decreased kaolin pH, and enhanced heavy metals removal efficiencies. The removal efficiencies of Cd, Cu, Ni, Pb, and Zn in PET-CNT treatment were 89.7%, 63.6%, 90.7%, 19.2%, and 88.7%, respectively. In comparison with the Pt/Ti and graphite treatments, the removal efficiencies of Cd, Ni, and Zn were improved at least about 30%, Cu and Pb were improved at least 16.6% and 6.9%, respectively. Our results demonstrated the PET-CNT was a good alternative cathode material for enhancing efficiency of EK remediation.

Copper and trace element fractionation in electrokinetically treated methanogenic anaerobic granular sludge

International Nuclear Information System (INIS)

Virkutyte, Jurate; Hullebusch, Eric van; Sillanpaeae, Mika; Lens, Piet

2005-01-01

The effect of electrokinetic treatment (0.15 mA cm -2 ) on the metal fractionation in anaerobic granular sludge artificially contaminated with copper (initial copper concentration 1000 mg kg -1 wet sludge) was studied. Acidification of the sludge (final pH 4.2 in the sludge bed) with the intention to desorb the copper species bound to the organic/sulfides and residual fractions did not result in an increased mobility, despite the fact that a higher quantity of copper was measured in the more mobile (i.e. exchangeable/carbonate) fractions at final pH 4.2 compared to circum-neutral pH conditions. Also addition of the chelating agent EDTA (Cu 2+ :EDTA 4- ratio 1.2:1) did not enhance the mobility of copper from the organic/sulfides and residual fractions, despite the fact that it induced a reduction of the total copper content of the sludge. The presence of sulfide precipitates likely influences the copper mobilisation from these less mobile fractions, and thus makes EDTA addition ineffective to solubilise copper from the granules. - Electrokinetic treatment of copper contaminated anaerobic granular sludge at 0.15 mA cm -2 for 14 days induces copper and trace metal mobility as well as changes in their fractionation (i.e. bonding forms)

Electrokinetic properties of tantalum oxide deposited on model substrate in NaCl and LiCl solutions

International Nuclear Information System (INIS)

Sidorova, M.P.; Bogdanova, N.F.; Ermakova, L.Eh.; Bobrov, P.V.

1997-01-01

Electrokinetic characteristics of tantalum oxide have been studied using a model system - a plane-parallel capillary in chloride solutions containing monocharge (H + , Na + , Li + ) counterions in a wide range of pH and concentrations. It is shown that position of isoelectric point (IEP) of Ta 2 O 5 depends on concentration and type of counterion, moreover, the dependence is not explained in the framework of classical notions of the influence of counterion specific adsorption on IEP position. Electrokinetic potential of Ta 2 O-5 surface at the background of diluted LiCl solutions is higher in its absolute value, than at the background of NaCl solutions according to direct lyotropic series. The results of measurements of the capillary resistance dependence on pH at the background of NaCl and LiCl solutions 10 -3 -10 -1 M are used for the calculation of efficiency and specific surface conductivity factors

Precipitation-filtering technology for uranium waste solution generated on washing-electrokinetic decontamination

Energy Technology Data Exchange (ETDEWEB)

Kim, Gye-Nam, E-mail: kimsum@kaeri.re.kr; Park, Uk-Ryang; Kim, Seung-Soo; Moon, Jei-Kwon

2015-05-15

Graphical abstract: A recycling process diagram for the volume reduction of waste solution generated from washing-electrokinetic decontamination. - Highlights: • A process for recycling a waste solution generated was developed. • The total metal precipitation rate by NaOH in a supernatant after precipitation was the highest at pH 9. • The uranium radioactivity in the treated solution upon injection of 0.2 g of alum was lower. • After drying, the volume of sludge was reduced to 35% of the initial sludge volume. - Abstract: Large volumes of uranium waste solution are generated during the operation of washing-electrokinetic decontamination equipment used to remove uranium from radioactive soil. A treatment technology for uranium waste solution generated upon washing-electrokinetic decontamination for soil contaminated with uranium has been developed. The results of laboratory-size precipitation experiments were as follows. The total amount of metal precipitation by NaOH for waste solution was highest at pH 11. Ca(II), K(I), and Al(III) ions in the supernatant partially remained after precipitation, whereas the concentration of uranium in the supernatant was below 0.2 ppm. Also, when NaOH was used as a precipitant, the majority of the K(I) ions in the treated solution remained. The problem of CaO is to need a long dissolution time in the precipitation tank, while Ca(OH){sub 2} can save a dissolution time. However, the volume of the waste solution generated when using Ca(OH){sub 2} increased by 8 mL/100 mL (waste solution) compared to that generated when using CaO. NaOH precipitant required lower an injection volume lower than that required for Ca(OH){sub 2} or CaO. When CaO was used as a precipitant, the uranium radioactivity in the treated solution at pH 11 reached its lowest value, compared to values of uranium radioactivity at pH 9 and pH 5. Also, the uranium radioactivity in the treated solution upon injection of 0.2 g of alum with CaO or Ca(OH){sub 2} was

Selective micellar electrokinetic chromatographic method for simultaneous determination of some pharmaceutical binary mixtures containing non-steroidal anti-inflammatory drugs

Directory of Open Access Journals (Sweden)

Michael E. El-Kommos

2013-02-01

Full Text Available A simple and selective micellar electrokinetic chromatographic (MEKC method has been developed for the analysis of five pharmaceutical binary mixtures containing three non-steroidal anti-inflammatory drugs (NSAIDs. The investigated mixtures were Ibuprofen (IP–Paracetamol (PC, Ibuprofen (IP–Chlorzoxazone (CZ, Ibuprofen (IP–Methocarbamol (MC, Ketoprofen (KP–Chlorzoxazone (CZ and Diclofenac sodium (DS–Lidocaine hydrochloride (LC. The separation was run for all mixtures using borate buffer (20 mM, pH 9 containing 15% (v/v methanol and 100 mM sodium dodecyl sulphate (SDS at 15 kV and the components were detected at 214 nm. Different factors affecting the electrophoretic mobility of the seven investigated drugs were studied and optimized. The method was validated according to international conference of harmonization (ICH guidelines and United States pharmacopoeia (USP. The method was applied to the analysis of five pharmaceutical binary mixtures in their dosage forms. The results were compared with other reported high performance liquid chromatographic methods and no significant differences were observed. Keywords: Capillary electrophoresis, Micellar electrokinetic chromatographic method, Non-steroidal anti-inflammatory drugs, Pharmaceutical binary mixtures, Pharmaceutical analysis

Electrokinetic treatment of polluted soil at pilot level coupled to an advanced oxidation process of its wastewater

Science.gov (United States)

Ochoa, B.; Ramos, L.; Garibay, A.; Pérez-Corona, M.; Cuevas, M. C.; Cárdenas, J.; Teutli, M.; Bustos, E.

2016-02-01

Soil contaminated with hydrocarbons is a current problem of great importance. These contaminants may be toxic, can retain water and block gas exchange with the atmosphere, which produces a poor-quality soil unsuitable for ecological health. Electroremediation is among the treatments for the removal of such contaminants. In this research, a pilot-level electroremediation test was applied using a circular arrangement of electrodes with a Ti cathode at the middle of the cell surrounded by six IrO2-Ta2O5 | Ti anodes. The presence of an NaOH electrolyte helps to develop the electromigration and electro-osmosis of gasoline molecules (at 1126 mg kg-1) surrounded by Na+ ions. The hydrocarbons are directed towards the cathode and subsequently removed in an aqueous Na+ - hydrocarbon solution, and the -OH migrates to the anode. During electrokinetic treatment, the physicochemical characteristics of the soil close to either the cathode or anode and at the half-cell were evaluated during the three weeks of treatment. During that time, more than 80% of hydrocarbons were removed. Hydrocarbons removed by the electrokinetic treatment of gasoline-polluted soil were collected in a central wastewater compartment and subsequently treated with a Fenton-type advanced oxidation process. This achieved more than 70% mineralization of the hydrocarbons to CO2 and H2O within 1.5 h; its low toxicity status was verified using the Deltatox® kit test. With this approach, the residual water complied with the permissible limits of COD, pH, and electrical conductivity for being discharged into water bodies, according to Mexican norm NOM-001-SEMARNAT-1996.

Electro-kinetic remediation coupled with phytoremediation to remove lead, arsenic and cesium from contaminated paddy soil.

Science.gov (United States)

Mao, Xinyu; Han, Fengxiang X; Shao, Xiaohou; Guo, Kai; McComb, Jacqueline; Arslan, Zikri; Zhang, Zhanyu

2016-03-01

The objectives of this study were to investigate distribution and solubility of Pb, Cs and As in soils under electrokinetic field and examine the processes of coupled electrokinetic phytoremediation of polluted soils. The elevated bioavailability and bioaccumulation of Pb, As and Cs in paddy soil under an electro-kinetic field (EKF) were studied. The results show that the EKF treatment is effective on lowering soil pH to around 1.5 near the anode which is beneficial for the dissolution of metal(loid)s, thus increasing their overall solubility. The acidification in the anode soil efficiently increased the water soluble (SOL) and exchangeable (EXC) Pb, As and Cs, implying enhanced solubility and elevated overall potential bioavailability in the anode region while lower solubility in the cathode areas. Bioaccumulations of Pb, As and Cs were largely determined by the nature of elements, loading levels and EKF treatment. The native Pb in soil usually is not bioavailable. However, EKF treatment tends to transfer Pb to the SOL and EXC fractions improving the phytoextraction efficiency. Similarly, EKF transferred more EXC As and Cs to the SOL fraction significantly increasing their bioaccumulation in plant roots and shoots. Pb and As were accumulated more in plant roots than in shoots while Cs was accumulated more in shoots due to its similarity of chemical properties to potassium. Indian mustard, spinach and cabbage are good accumulators for Cs. Translocation of Pb, As and Cs from plant roots to shoots were enhanced by EKF. However, this study indicated the overall low phytoextraction efficiency of these plants. Copyright © 2015 Elsevier Inc. All rights reserved.

Synergistic effects of bioremediation and electrokinetics in the remediation of petroleum-contaminated soil.

Science.gov (United States)

Guo, Shuhai; Fan, Ruijuan; Li, Tingting; Hartog, Niels; Li, Fengmei; Yang, Xuelian

2014-08-01

The present study evaluated the coupling interactions between bioremediation (BIO) and electrokinetics (EK) in the remediation of total petroleum hydrocarbons (TPH) by using bio-electrokinetics (BIO-EK) with a rotatory 2-D electric field. The results demonstrated an obvious positive correlation between the degradation extents of TPH and electric intensity both in the EK and BIO-EK tests. The use of BIO-EK showed a significant improvement in degradation of TPH as compared to BIO or EK alone. The actual degradation curve in BIO-EK tests fitted well with the simulated curve obtained by combining the degradation curves in BIO- and EK-only tests during the first 60 d, indicating a superimposed effect of biological degradation and electrochemical stimulation. The synergistic effect was particularly expressed during the later phase of the experiment, concurrent with changes in the microbial community structure. The community composition changed mainly according to the duration of the electric field, leading to a reduction in diversity. No significant spatial shifts in microbial community composition and bacterial numbers were detected among different sampling positions. Soil pH was uniform during the experimental process, soil temperature showed no variations between the soil chambers with and without an electric field. Copyright © 2014 Elsevier Ltd. All rights reserved.

Modeling of electrokinetic processes by finite element integration of the Nernst–Planck–Poisson system of equations

DEFF Research Database (Denmark)

Paz-Garcia, Juan Manuel; Johannesson, Björn; Ottosen, Lisbeth M.

2011-01-01

equilibrium is continuously assured and the pH value is monitored. Results from some selected test simulations of the electrokinetic desalination of a sample of porous material are presented, outlining the versatility of the model as well as showing the effect of the counterion in the removal rate of a target...

Electrokinetic investigations on the system polystyrene/aqueous electrolyte solution : verification of model theories on dilute and concentrated dispersions

NARCIS (Netherlands)

Put, van der A.G.

1980-01-01

This thesis presents a systematic experimental and theoretical study on electrokinetic and electroconducting properties of disperse systems. The increasing interest in transport processes through charged porous systems has recently brought about a corresponding growth of models and theories since

A multiscale theoretical investigation of electric measurements in living bone : piezoelectricity and electrokinetics.

Science.gov (United States)

Lemaire, T; Capiez-Lernout, E; Kaiser, J; Naili, S; Rohan, E; Sansalone, V

2011-11-01

This paper presents a theoretical investigation of the multiphysical phenomena that govern cortical bone behaviour. Taking into account the piezoelectricity of the collagen-apatite matrix and the electrokinetics governing the interstitial fluid movement, we adopt a multiscale approach to derive a coupled poroelastic model of cortical tissue. Following how the phenomena propagate from the microscale to the tissue scale, we are able to determine the nature of macroscopically observed electric phenomena in bone.

Pilot Field Test of Electrokinetically-Delivered and Thermally Activated Persulfate (EKTAP) for Remediation of Chlorinated Solvents in Clay

Science.gov (United States)

O'Carrol, D. M.; Head, N.; Chowdhury, A. I.; Inglis, A.; Garcia, A. N.; Reynolds, D. A.; Hayman, J.; Hogberg, D.; Austrins, L. M.; Sidebottom, A.; Auger, M.; Eimers, J.; Gerhard, J.

2017-12-01

Remediation of low-permeability soils that are contaminated with chlorinated solvents is challenging. In-situ chemical oxidation (ISCO) with persulfate is promising, however, the delivery of the oxidant by hydraulic gradient is limited in low-permeability soils. Electrokinetic (EK) enhanced transport of amendments has shown the potential to overcome these limitations. In particular, the combined technology of EK-delivered and thermally activated persulfate (EKTAP) has been recently demonstrated in the laboratory as promising in these challenging environments (Chowdhury A. I. (2016) Hydraulic and Electrokinetic Delivery of Remediants for In-situ Remediation. Electronic Thesis and Dissertation Repository, Paper 4135). This study presents the first pilot field test to evaluate EKTAP to enhance the distribution and effectiveness of persulfate in clayey soil. The pilot field test was conducted at a contaminated site formerly occupied by a chlorinated solvent production facility. In the EK transport phase, 925 L of 40 g/L persulfate was injected over 57 days, during which 9A of direct current (DC) was applied between two electrodes spaced 3 m apart. In the subsequent heating phase, 10A of alternate current (AC) was applied across the same electrodes for an additional 70 days. Extensive sampling of soil and groundwater in this EKTAP cell were compared to those from two parallel control cells, one with EK only and one with no electrodes. Results indicated that EK can significantly increase transport rates of persulfate in clayey soil. Persulfate activation primarily occurred in the period of DC application, indicating that the natural reduction capacity of the clay soil had a significant impact on persulfate decomposition. Temperature mapping indicated that AC current was able to increase soil temperatures, validating the EKTAP concept. Degradation of chlorinated compounds, in particular, 1-2, dichloroethane (1,2- DCA), was observed to be substantial in areas of persulfate

Electrokinetic delivery of persulfate to remediate PCBs polluted soils: effect of injection spot.

Science.gov (United States)

Fan, Guangping; Cang, Long; Fang, Guodong; Qin, Wenxiu; Ge, Liqiang; Zhou, Dongmei

2014-12-01

Persulfate-based in situ chemical oxidation (ISCO) is a promising technique for the remediation of organic compounds contaminated soils. Electrokinetics (EK) provides an alternative method to deliver oxidants into the target zones especially in low permeable-soil. In this study, the flexibility of delivering persulfate by EK to remediate polychlorinated biphenyls (PCBs) polluted soil was investigated. 20% (w/w) of persulfate was injected at the anode, cathode and both electrodes to examine its transport behaviors under electrical field, and the effect of field inversion process was also evaluated. The results showed that high dosage of persulfate could be delivered into S4 section (near cathode) by electroosmosis when persulfate was injected from anode, 30.8% of PCBs was removed from the soil, and the formed hydroxyl precipitation near the cathode during EK process impeded the transportation of persulfate. In contrast, only 18.9% of PCBs was removed with the injection of persulfate from cathode, although the breakthrough of persulfate into the anode reservoir was observed. These results indicated that the electroosmotic flow is more effective for the transportation of persulfate into soil. The addition of persulfate from both electrodes did not significantly facilitate the PCBs oxidation as well as the treatment of electrical field reversion, the reinforced negative depolarization function occurring in the cathode at high current consumed most of the oxidant. Furthermore, it was found that strong acid condition near the anode favored the oxidation of PCBs by persulfate and the degradation of PCBs was in consistent with the oxidation of Soil TOC in EK/persulfate system. Copyright © 2014 Elsevier Ltd. All rights reserved.

Solid/solution Cu fractionations/speciation of a Cu contaminated soil after pilot-scale electrokinetic remediation and their relationships with soil microbial and enzyme activities

International Nuclear Information System (INIS)

Wang Quanying; Zhou Dongmei; Cang Long; Li Lianzhen; Wang Peng

2009-01-01

The aim of this study was to investigate the detailed metal speciation/fractionations of a Cu contaminated soil before and after electrokinetic remediation as well as their relationships with the soil microbial and enzyme activities. Significant changes in the exchangeable and adsorbed-Cu fractionations occurred after electrokinetic treatment, while labile soil Cu in the solution had a tendency to decrease from the anode to the cathode, and the soil free Cu 2+ ions were mainly accumulated in the sections close to the cathode. The results of regression analyses revealed that both the soil Cu speciation in solution phase and the Cu fractionations in solid phase could play important roles in the changes of the soil microbial and enzyme activities. Our findings suggest that the bioavailability of soil heavy metals and their ecotoxicological effects on the soil biota before and after electroremediation can be better understood in terms of their chemical speciation and fractionations. - The assessment of the roles of soil solution speciation and solid-phase fractionations in metal bioavailability after electrokinetic remediation deserves close attention.

A multiphase electrokinetic flow model for electrolytes with liquid/liquid interfaces

Energy Technology Data Exchange (ETDEWEB)

Berry, J.D., E-mail: joe.d.berry@gmail.com; Davidson, M.R., E-mail: m.davidson@unimelb.edu.au; Harvie, D.J.E., E-mail: daltonh@unimelb.edu.au

2013-10-15

A numerical model for electrokinetic flow of multiphase systems with deformable interfaces is presented, based on a combined level set-volume of fluid technique. A new feature is a multiphase formulation of the Nernst–Planck transport equation for advection, diffusion and conduction of individual charge carrier species that ensures their conservation in each fluid phase. The numerical model is validated against the analytical results of Zholkovskij et al. (2002) [1], and results for the problem of two drops coalescing in the presence of mobile charge carriers are presented. The time taken for two drops containing ions to coalesce decreases with increasing ion concentration.

Effects of surface roughness and electrokinetic heterogeneity on electroosmotic flow in microchannel

Energy Technology Data Exchange (ETDEWEB)

Masilamani, Kannan; Ganguly, Suvankar; Feichtinger, Christian; Bartuschat, Dominik; Rüde, Ulrich, E-mail: suva_112@yahoo.co.in [Department of Computer Science 10 University of Erlangen-Nuremberg, Cauerstr.11 91058 Erlangen (Germany)

2015-06-15

In this paper, a hybrid lattice-Boltzmann and finite-difference (LB-FD) model is applied to simulate the effects of three-dimensional surface roughness and electrokinetic heterogeneity on electroosmotic flow (EOF) in a microchannel. The lattice-Boltzmann (LB) method has been employed to obtain the flow field and a finite-difference (FD) method is used to solve the Poisson-Boltzmann (PB) equation for the electrostatic potential distribution. Numerical simulation of flow through a square cross-section microchannel with designed roughness is conducted and the results are critically analysed. The effects of surface heterogeneity on the electroosmotic transport are investigated for different roughness height, width, roughness interval spacing, and roughness surface potential. Numerical simulations reveal that the presence of surface roughness changes the nature of electroosmotic transport through the microchannel. It is found that the electroosmotic velocity decreases with the increase in roughness height and the velocity profile becomes asymmetric. For the same height of the roughness elements, the EOF velocity rises with the increase in roughness width. For the heterogeneously charged rough channel, the velocity profile shows a distinct deviation from the conventional plug-like flow pattern. The simulation results also indicate locally induced flow vortices which can be utilized to enhance the flow and mixing within the microchannel. The present study has important implications towards electrokinetic flow control in the microchannel, and can provide an efficient way to design a microfluidic system of practical interest. (paper)

Electrokinetic migration across artificial liquid membranes. New concept for rapid sample preparation of biological fluids.

Science.gov (United States)

Pedersen-Bjergaard, Stig; Rasmussen, Knut Einar

2006-03-24

Basic drug substances were transported across a thin artificial organic liquid membrane by the application of 300 V d.c. From a 300 microl aqueous donor compartment (containing 10 mM HCl), the drugs migrated through a 200 microm artificial liquid membrane of 2-nitrophenyl octyl ether immobilized in the pores of a polypropylene hollow fiber, and into a 30 microl aqueous acceptor solution of 10 mM HCl inside the lumen of the hollow fiber. The transport was forced by an electrical potential difference sustained over the liquid membrane, resulting in electrokinetic migration of drug substances from the donor compartment to the acceptor solution. Within 5 min of operation at 300 V, pethidine, nortriptyline, methadone, haloperidol, and loperamide were extracted with recoveries in the range 70-79%, which corresponded to enrichments in the range 7.0-7.9. The chemical composition of the organic liquid membrane strongly affected the permeability, and may serve as an efficient tool for controlling the transport selectivity. Water samples, human plasma, and human urine were successfully processed, and in light of the present report, electrokinetic migration across thin artificial liquid membranes may be an interesting tool for future isolation within chemical analysis.

Optimisation of resolution in micellar electrokinetic chromatography by multivariate evaluation of electrolytes.

Science.gov (United States)

Mikaeli, S; Thorsén, G; Karlberg, B

2001-01-12

A novel approach to multivariate evaluation of separation electrolytes for micellar electrokinetic chromatography is presented. An initial screening of the experimental parameters is performed using a Plackett-Burman design. Significant parameters are further evaluated using full factorial designs. The total resolution of the separation is calculated and used as response. The proposed scheme has been applied to the optimisation of the separation of phenols and the chiral separation of (+)-1-(9-anthryl)-2-propyl chloroformate-derivatized amino acids. A total of eight experimental parameters were evaluated and optimal conditions found in less than 48 experiments.

Comparison of migration modeling in micellar electrokinetic chromatography by linear regression and by use of an artificial neural network

NARCIS (Netherlands)

Metting, HJ; van Zomeren, PV; van der Ley, CP; Coenegracht, PMJ; de Jong, GJ

2000-01-01

The concentrations of modifier (methanol or acetonitrile) and surfactant (sodium dodecyl sulfate SDS) in the running buffer are important factors influencing the mobility of analytes in micellar electrokinetic chromatography (MEKC). Response surfaces of the effective mobility can be used to predict

Flow reversal at low voltage and low frequency in a microfabricated ac electrokinetic pump

DEFF Research Database (Denmark)

Gregersen, Misha Marie; Olesen, Laurits Højgaard; Brask, Anders

2007-01-01

measured in a regime, where both the applied voltage and the frequency are low, Vrms1.5 V and f20 kHz, compared to previously investigated parameter ranges. The impedance spectrum has been thoroughly measured and analyzed in terms of an equivalent circuit diagram to rule out trivial circuit explanations......Microfluidic chips have been fabricated in Pyrex glass to study electrokinetic pumping generated by a low-voltage ac bias applied to an in-channel asymmetric metallic electrode array. A measurement procedure has been established and followed carefully resulting in a high degree of reproducibility...... of the measurements over several days. A large coverage fraction of the electrode array in the microfluidic channels has led to an increased sensitivity allowing for pumping measurements at low bias voltages. Depending on the ionic concentration a hitherto unobserved reversal of the pumping direction has been...

Experimental and numerical study of deposit formation in secondary side SG TSP by electrokinetic approach

International Nuclear Information System (INIS)

Guillodo, Michael; Foucault, Marc; Ryckelynck, Natacha; Chahma, Farah; Guingo, Mathieu; Mansour, Carine; Alos-Ramos, Olga; Corredera, Geraldine

2012-09-01

Corrosion products deposit formation observed in PWR steam generators (SGs) - related to SG free span fouling and SG clogging - is now reported since several years. SG clogging is a localized phenomenon observed between the leading edge of the Tube Support Plate (TSP) and SG tubing materials. Based on visual inspections, it was found that the gaps between SG tubing material and TSP at the lower part of the broached holes were getting progressively blocked. Therefore, for safe operation, most affected PWRs had to be operated at reduced power. TSP blockage was mainly observed for low-pH water chemistry conditioning, which directly depends on the operating water chemistry. The TSP blockage mechanism is complex due to the localized conditions in which flow pattern change, chemistry and electrochemical conditions are not well understood. Electrokinetic considerations could be pointed out to explain the coupling of chemistry, materials and thermohydraulic (T/H) conditions. In this frame AREVA and EDF have launched a long-term R and D program in order to understand the mechanisms driving the formation of SG clogging. This study based on parametric laboratory tests aims to assess the role of secondary water chemistry, material and T/H conditions on deposit formation. The experimental approach focused on electrokinetic measurements of metallic substrates and on the assessment of oxidation properties of materials in secondary side chemistry. An overall analysis of recent results is presented to address SG deposit formation in secondary water chemistry for various conditioning amines - morpholine, ethanolamine and dimethylamine. To complete the study, the experimental results have been correlated to CFD simulations of particle deposition, by means of stochastic Lagrangian models. These calculations have in particular reproduced correctly the location of the most important particle deposit (the leading edge of the test tube), and have stressed the influence of the

Determination of Sodium deoxycolate residues in vaccinal formulation by micellar electrokinetic chromatography

International Nuclear Information System (INIS)

Merchan, Yaima; Lucangioli, Silvia; Carducci, Clyde

2011-01-01

The sodium deoxycholate (DCNa) source is the surfactant used in the biopharmaceutical industry for the solubilization of outer membrane vesicles. It is well known the importance of control of this metabolite in biological materials due to its high toxicity for humans. To demonstrate significant small variations of this metabolite in vaccine formulations it is necessary to use a methodology highly selective, sensitive, specific and reproducible. In this report we used the micellar electrokinetic chromatography (MEKC) in a Capillary Ion Analyzer (Water corp. Milford MA) detection at 185 nm mercury lamp. It employed a fused silica capillary uncoated (Waters Corp. Milford MA). We assessed the purity of 2 lots of sodium deoxycholate and analyzed 15 samples of purified vesicles active pharmaceutical ingredient vaccine formulations. Data were recorded and processed with software Millennium TM (Waters Corp. Milford MA). It was found that lots of sodium deoxycholate containing 1.19 and 0.44% cholic acid and contaminate that 93% of the purified vesicles samples were from 0 to 2.44 mg protein DCNa/100 μg. MECK's results were compared with a kinetic test used to determine bile acids in blood (Merckotest). MECK system showed better results regarding the Merkotest

Role of Bismuth in the Electrokinetics of Silicon Photocathodes for Solar Rechargeable Vanadium Redox Flow Batteries.

Science.gov (United States)

Flox, Cristina; Murcia-López, Sebastián; Carretero, Nina M; Ros, Carles; Morante, Juan R; Andreu, Teresa

2018-01-10

The ability of crystalline silicon to photoassist the V 3+ /V 2+ cathodic reaction under simulated solar irradiation, combined with the effect of bismuth have led to important electrochemical improvements. Besides the photovoltage supplied by the photovoltaics, additional decrease in the onset potentials, high reversibility of the V 3+ /V 2+ redox pair, and improvement in the electrokinetics were attained thanks to the addition of bismuth. In fact, Bi 0 deposition has shown to slightly decrease the photocurrent, but the significant enhancement in the charge transfer, reflected in the overall electrochemical performance clearly justifies its use as additive in a photoassisted system for maximizing the efficiency of solar charge to battery. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Novel Technique to improve the pH of Acidic Barren Soil using Electrokinetic-bioremediation with the application of Vetiver Grass

Science.gov (United States)

Azhar, A. T. S.; Nabila, A. T. A.; Nurshuhaila, M. S.; Zaidi, E.; Azim, M. A. M.; Zahin, A. M. F.

2016-11-01

Residual acidic slopes which are not covered by vegetation greatly increases the risk of soil erosion. In addition, low soil pH can bring numerous problems such as Al and Fe toxicity, land degradation issues and some problems related to vegetation. In this research, a series of electrokinetic bioremediation (EK-Bio) treatments using Bacillus sphaericus, Bacillus subtilis and Pseudomonas putida with a combination of Vetiver grass were performed in the laboratory. Investigations were conducted for 14 days and included the observation of changes in the soil pH and the mobilization of microorganism cells through an electrical gradient of 50 V/m under low pH. Based on the results obtained, this study has successfully proven that the pH of soil increases after going through electrokinetic bioremediation (EK-Bio). The treatment using Bacillus sphaericus increases the pH from 2.95 up to 4.80, followed by Bacillus subtilis with a value of 4.66. Based on the overall performance, Bacillus sphaericus show the highest number of bacterial cells in acidic soil with a value of 6.6 × 102 cfu/g, followed by Bacillus subtilis with a value of 5.7 × 102 cfu/g. In conclusion, Bacillus sphaericus and Bacillus subtilis show high survivability and is suitable to be used in the remediation of acidic soil.

High current ion sources

International Nuclear Information System (INIS)

Brown, I.G.

1989-06-01

The concept of high current ion source is both relative and evolutionary. Within the domain of one particular kind of ion source technology a current of microamperers might be 'high', while in another area a current of 10 Amperes could 'low'. Even within the domain of a single ion source type, what is considered high current performance today is routinely eclipsed by better performance and higher current output within a short period of time. Within their fields of application, there is a large number of kinds of ion sources that can justifiably be called high current. Thus, as a very limited example only, PIGs, Freemen sources, ECR sources, duoplasmatrons, field emission sources, and a great many more all have their high current variants. High current ion beams of gaseous and metallic species can be generated in a number of different ways. Ion sources of the kind developed at various laboratories around the world for the production of intense neutral beams for controlled fusion experiments are used to form large area proton deuteron beams of may tens of Amperes, and this technology can be used for other applications also. There has been significant progress in recent years in the use of microwave ion sources for high current ion beam generation, and this method is likely to find wide application in various different field application. Finally, high current beams of metal ions can be produced using metal vapor vacuum arc ion source technology. After a brief consideration of high current ion source design concepts, these three particular methods are reviewed in this paper

Salt Induced Decay of Masonry and Electrokinetic Repair

DEFF Research Database (Denmark)

Ottosen, Lisbeth M.; Rörig-Dalgaard, Inge

in brick depending on its water content and salts may be precipitated on the outer wall or concentrated under paint layers covering the surface of the brick. Different types of damage may appear in masonry walls due to these concentrating phenomena. Bricks themselves can be destroyed and the mortar can...... of bricks without increased salt content is very low compared to soils in general. Furthermore in a masonry wall there are boundaries with different chemistry (e.g. pH) that the ions must pass, brick-mortar boundaries. From initial experiments with electrokinetic removal of Ca2+ ions from bricks good......Salt induced decay of bricks is caused when salts exert internal pressures, which exceed the strength of the stone. The presence of aqueous electrolyte solutions in the capillary pores of brick materials can under changing climate conditions cause deterioration of wall structures. Ions move...

ELECTROKINETIC DEVICE AND METHOD FOR CONSOLIDATING POROUS MATERIALS

DEFF Research Database (Denmark)

2017-01-01

The invention relates to a device and an associated electrokinetic method which allows the pores (superficial and deep) of a porous material to be filled, by forcing the precipitation therein of a product of low solubility in water by creating an electric field which will mobilise the cations...... and anions supplied by previously selected solutions. This method comprises two phases. In the first phase, the pores located at a specified distance from the surface of contact between the porous material and the anodic or cathodic compartment are plugged. In a second phase, the rest of the pores, mainly...... those which are on the surface level, are collapsed. As a result of the designed device and the plugging system contained therein, the porous material is not affected at any moment by chemical alteration processes caused by contact with extreme pH values. This device allows the treatment to be applied...

Rapid and label-free separation of Burkitt's lymphoma cells from red blood cells by optically-induced electrokinetics.

Directory of Open Access Journals (Sweden)

Wenfeng Liang

Full Text Available Early stage detection of lymphoma cells is invaluable for providing reliable prognosis to patients. However, the purity of lymphoma cells in extracted samples from human patients' marrow is typically low. To address this issue, we report here our work on using optically-induced dielectrophoresis (ODEP force to rapidly purify Raji cells' (a type of Burkitt's lymphoma cell sample from red blood cells (RBCs with a label-free process. This method utilizes dynamically moving virtual electrodes to induce negative ODEP force of varying magnitudes on the Raji cells and RBCs in an optically-induced electrokinetics (OEK chip. Polarization models for the two types of cells that reflect their discriminate electrical properties were established. Then, the cells' differential velocities caused by a specific ODEP force field were obtained by a finite element simulation model, thereby established the theoretical basis that the two types of cells could be separated using an ODEP force field. To ensure that the ODEP force dominated the separation process, a comparison of the ODEP force with other significant electrokinetics forces was conducted using numerical results. Furthermore, the performance of the ODEP-based approach for separating Raji cells from RBCs was experimentally investigated. The results showed that these two types of cells, with different concentration ratios, could be separated rapidly using externally-applied electrical field at a driven frequency of 50 kHz at 20 Vpp. In addition, we have found that in order to facilitate ODEP-based cell separation, Raji cells' adhesion to the OEK chip's substrate should be minimized. This paper also presents our experimental results of finding the appropriate bovine serum albumin concentration in an isotonic solution to reduce cell adhesion, while maintaining suitable medium conductivity for electrokinetics-based cell separation. In short, we have demonstrated that OEK technology could be a promising tool for

Fluoro-apatite surface composition in aqueous solution deduced from potentiometric, electrokinetic, and solubility measurements, and spectroscopic observations

International Nuclear Information System (INIS)

Chairat, C.; Oelkers, E.H.; Schott, J.; Lartigue, J.E.

2007-01-01

The surface chemistry of fluoro-apatite in aqueous solution was investigated using electrokinetic techniques, potentiometric titrations, solubility measurements, and attenuated total reflection infrared spectroscopy. All methods indicate the formation of Ca/F depleted, P enriched altered layer via exchange reactions between H + and Ca 2+ , and OH - and F - at the fluoro-apatite (FAP) surface. Observations suggest that this leached layer has a di-calcium phosphate (CaHPO 4 ) composition and that it controls the apparent solubility of FAP. Electrokinetic measurements yield an iso-electric point value of 1 ± 0.5 consistent with a negatively charged FAP surface at pH ≥ 1. In contrast, surface titrations give an apparent pH of point of zero charge of similar to 7.7, consistent with a positively charged surface at pH ≤ 7.7. These differences are shown to stem from proton consumption by both proton exchange and dissolution reactions at the FAP surface. After taking account for these effects, FAP surface charge is shown to be negative to at least pH 4 by surface titration analysis. (authors)

A Novel Combination of Surfactant Addition and Persulfate-assisted Electrokinetic Oxidation for Remediation of Pyrene-Contaminated Soil

Directory of Open Access Journals (Sweden)

M. Abtahi

2018-03-01

Full Text Available Effect of surfactant addition on persulfate-assisted electrokinetic remediation of pyrene-spiked soil was studied. The influence of effective factors including voltage, surfactant addition, moisture content, and persulfate concentration on the removal of initial pyrene concentration of 200 mg kg–1 were investigated. A complete pyrene removal was observed for voltage of 1 V cm–1, saturated conditions, Tween 80 concentration of 20 mL kg–1, and persulfate concentration of 100 mg kg–1 after 24 h, corresponding to pyrene mineralization of 61 %, based on TPH analysis. The experimental results were best fitted with pseudo-first-order kinetic model with correlation coefficient of 0.968 and rate constant of 0.191 min−1. The main intermediates of pyrene degradation were benzene o-toluic acid, acetic, azulene, naphthalene and decanoic acid. Finally, an unwashed hydrocarbon-contaminated soil was subjected to persulfate-assisted electrokinetic remediation, and a TPH removal of 38 % was observed for the initial TPH content of 912 mg kg–1, under the selected conditions.

Determination of lysergic acid diethylamide (LSD) in mouse blood by capillary electrophoresis/ fluorescence spectroscopy with sweeping techniques in micellar electrokinetic chromatography.

Science.gov (United States)

Fang, Ching; Liu, Ju-Tsung; Chou, Shiu-Huey; Lin, Cheng-Huang

2003-03-01

The separation and on-line concentration of lysergic acid diethylamide (LSD) in mouse blood was achieved by means of capillary electrophoresis/fluorescence spectroscopy using sodium dodecyl sulfate (SDS) as the surfactant. Techniques involving on-line sample concentration, including sweeping micellar electrokinetic chromatography (sweeping-MEKC) and cation-selective exhaustive injection-sweep-micellar electrokinetic chromatography (CSEI-sweep-MEKC) were applied; the optimum on-line concentration and separation conditions were determined. In the analysis of an actual sample, LSD was found in a blood sample from a test mouse (0.1 mg LSD fed to a 20 g mouse; approximately 1/10 to the value of LD(50)). As a result, 120 and 30 ng/mL of LSD was detected at 20 and 60 min, respectively, after ingestion of the doses.

Electro-Kinetic Pumping with Slip Irreversibility in Heat Exchange of CSP-Powered Bio-Digester Assemblies

OpenAIRE

Ogedengbe, Emmanuel; Rosen, Marc

2012-01-01

Parametric studies of the effects of slip irreversibility in concentrating solar power (CSP)-powered bio-digester assemblies are investigated. Complexities regarding the identification of the appropriate electro-kinetic phenomena for certain electrolyte phases are reviewed. The application of exergy analysis to the design of energy conversion devices, like solar thermal collectors, for the required heat of formation in a downdraft waste food bio-digester, is discussed. Thermal management in t...

High speed capillary zone electrophoresis-mass spectrometry via an electrokinetically pumped sheath flow interface for rapid analysis of amino acids and a protein digest.

Science.gov (United States)

Schiavone, Nicole M; Sarver, Scott A; Sun, Liangliang; Wojcik, Roza; Dovichi, Norman J

2015-06-01

While capillary zone electrophoresis (CZE) has been used to produce very rapid and efficient separations, coupling these high-speed separations with mass spectrometry (MS) has been challenging. Now, with much faster and sensitive mass spectrometers, it is possible to take full advantage of the CZE speed and reconstruct the fast migrating peaks. Here are three high-speed CZE-MS analyses via an electrokinetically pumped sheath-flow interface. The first separation demonstrates CZE-ESI-MS of an amino acid mixture with a 2-min separation, >50,000 theoretical plates, low micromolar concentration detection limits, and subfemtomole mass detection limits (LTQ XL mass spectrometer). The second separation with our recently improved third-generation CE-MS interface illustrates a 20 amino acid separation in ∼7min with an average over 200,000 plate counts, and results in almost-baseline resolution of structural isomers, leucine and isoleucine. The third separation is of a BSA digest with a reproducible CZE separation and mass spectrometry detection in 2min. CZE-MS/MS analysis of the BSA digest identified 31 peptides, produced 52% sequence coverage, and generated a peak capacity of ∼40 across the 1-min separation window (Q-Exactive mass spectrometer). Copyright © 2015 Elsevier B.V. All rights reserved.

High current, high bandwidth laser diode current driver

Science.gov (United States)

Copeland, David J.; Zimmerman, Robert K., Jr.

1991-01-01

A laser diode current driver has been developed for free space laser communications. The driver provides 300 mA peak modulation current and exhibits an optical risetime of less than 400 ps. The current and optical pulses are well behaved and show minimal ringing. The driver is well suited for QPPM modulation at data rates up to 440 Mbit/s. Much previous work has championed current steering circuits; in contrast, the present driver is a single-ended on/off switch. This results in twice the power efficiency as a current steering driver. The driver electrical efficiency for QPPM data is 34 percent. The high speed switch is realized with a Ku-band GaAsFET transistor, with a suitable pre-drive circuit, on a hybrid microcircuit adjacent to the laser diode.

Rapid analysis of caffeine in “smart drugs” and “energy drinks” by microemulsion electrokinetic chromatography (MEEKC)

Czech Academy of Sciences Publication Activity Database

Liotta, E.; Gottardo, R.; Seri, C.; Rimondo, C.; Mikšík, Ivan; Serpelloni, G.; Tagliaro, F.

2012-01-01

Roč. 220, 1-3 (2012), s. 279-283 ISSN 0379-0738 R&D Projects: GA ČR(CZ) GA203/08/1428 Institutional research plan: CEZ:AV0Z50110509 Institutional support: RVO:67985823 Keywords : caffeine * energy drink * smart drug * microemulsion electrokinetic chromatography Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.307, year: 2012

Electrokinetic-Enhanced Remediation of Phenanthrene-Contaminated Soil Combined with Sphingomonas sp. GY2B and Biosurfactant.

Science.gov (United States)

Lin, Weijia; Guo, Chuling; Zhang, Hui; Liang, Xujun; Wei, Yanfu; Lu, Guining; Dang, Zhi

2016-04-01

Electrokinetic-microbial remediation (EMR) has emerged as a promising option for the removal of polycyclic aromatic hydrocarbons (PAHs) from contaminated soils. The aim of this study was to enhance degradation of phenanthrene (Phe)-contaminated soils using EMR combined with biosurfactants. The electrokinetic (EK) remediation, combined with Phe-degrading Sphingomonas sp. GY2B, and biosurfactant obtained by fermentation of Pseudomonas sp. MZ01, degraded Phe in the soil with an efficiency of up to 65.1 % at the anode, 49.9 % at the cathode after 5 days of the treatment. The presence of biosurfactants, electricity, and a neutral electrolyte stimulated the growth of the degrading bacteria as shown by a rapid increase in microbial biomass with time. The electrical conductivity and pH changed little during the course of the treatment, which benefitted the growth of microorganisms and the remediation of Phe-contaminated soil. The EMR system with the addition of biosurfactant had the highest Phe removal, demonstrating the biosurfactant may enhance the bioavailability of Phe and the interaction with the microorganism. This study suggests that the EMR combined with biosurfactants can be used to enhance in situ bioremediation of PAH-contaminated soils.

Zn (II) Removal from River Water Samples of Sembrong, Johor State, Malaysia by Electrokinetic Remediation

Science.gov (United States)

Zaidi, E.; Husna, MNF; Shakila, A.; Azhar, ATS; Arif, AM; Norshuhaila, MS

2017-08-01

Heavy metals pollution has become one of the most serious environmental problems today. The treatment of heavy metals is of special concern due to their recalcitrance and persistence in the environment. Even many physical, chemical and biological treatment processes have been proposed to remove heavy metals from river water, the use of these treatment processes are not efficient and relatively costly. This study focused on the potential application of electrokinetic (EK) remediation in Sembrong River water to remove zinc (Zn2+). The physicochemical and biological parameters and water quality index (WQI) of Sembrong River water was characterized. The electrokinetic remediation experiments were performed by controlling pH, and electric density on voltage were observed and investigated. The results indicated that all physicochemical and biological parameters of Sembrong River complied with the standard discharged limit set by the Department of Environment (DOE). However, suspended solids (SS) and pH can be categorized as Class III according to INWQS. The best performance of 88% efficiency of zinc can be achieved EK experiment run at a fixed voltage of 30 V at pH 5.14 after 60 min of the process operate. This technology may be proposed for faster and eco-friendly removal of heavy metals in the environment.

Determination of water-soluble vitamins in multivitamin dietary supplements and in artichokes by micellar electrokinetic chromatography.

Science.gov (United States)

Serni, Enrico; Audino, Valeria; Del Carlo, Sara; Manera, Clementina; Saccomanni, Giuseppe; Macchia, Marco

2013-01-01

Several procedures of extraction with solvents for the simultaneous determination of vitamin C and some vitamins belonging to the B group (thiamine, riboflavine, nicotinic acid and nicotinamide) in multivitamin preparations and in artichokes (Cynara cardunculus subsp. scolymus [L.] Hegi) were developed. Different experimental conditions were used, in terms of heat treatment, composition and pH of the extraction mixture, with particular attention to high-temperature steps; purification of the extracts with solid phase extraction and stabilisation through lyophilisation were discussed. Analyses of the extracts were conducted by capillary electrophoresis in micellar electrokinetic chromatography modality. Borate buffer at pH 8.2 was used, and sodium dodecyl sulphate was added to the background electrolyte as surfactant. A range of linearity was determined and calibration curves were plotted for all the analytes.

Environmental monitoring of phenolic pollutants in water by cloud point extraction prior to micellar electrokinetic chromatography.

Science.gov (United States)

Stege, Patricia W; Sombra, Lorena L; Messina, Germán A; Martinez, Luis D; Silva, María F

2009-05-01

Many aromatic compounds can be found in the environment as a result of anthropogenic activities and some of them are highly toxic. The need to determine low concentrations of pollutants requires analytical methods with high sensitivity, selectivity, and resolution for application to soil, sediment, water, and other environmental samples. Complex sample preparation involving analyte isolation and enrichment is generally necessary before the final analysis. The present paper outlines a novel, simple, low-cost, and environmentally friendly method for the simultaneous determination of p-nitrophenol (PNP), p-aminophenol (PAP), and hydroquinone (HQ) by micellar electrokinetic capillary chromatography after preconcentration by cloud point extraction. Enrichment factors of 180 to 200 were achieved. The limits of detection of the analytes for the preconcentration of 50-ml sample volume were 0.10 microg L(-1) for PNP, 0.20 microg L(-1) for PAP, and 0.16 microg L(-1) for HQ. The optimized procedure was applied to the determination of phenolic pollutants in natural waters from San Luis, Argentina.

Effects of gamma-irradiation on the electrokinetic properties of purple membranes

International Nuclear Information System (INIS)

Doltchinkova, V.; Baldjiiska, M.; Stoilova, S.

1998-01-01

The effect of gamma-irradiation (5, 10 and 15 Gy) on the kinetic surface charge of purple membranes (PM) was followed by means of particle microelectrophoresis. The changes in electrophoretic mobility (EPM) were examined at 2, 5 and 26 h, respectively, following irradiation of native PM, and at 2, 26, 50 h and 5 days following irradiation of delipidated PM. It was concluded that the high inhomogeneity of the suspension, even after sonication, largely affects the measured zeta-potential. The 15-Gy treatment significantly increased the net negative surface charge density at 5 and 26 h after irradiation of native PM. However, the opposite effect of approximately twofold reduction of EPM values was derived from simultaneous studies concerning their delipidated form. Low irradiation doses clearly induced an enhancement of negative surface charge density at 2 h post-exposure as well as the formation of unstable structures of delipidated PM. The changes in electrokinetic properties might reflect the specific aggregate formation in both native and delipidated PM. It was suggested that the effect observed of both types of PM was mainly a structural phenomenon possibly related to the modification of functionally active residues. (orig.)

Electrokinetic enhanced bioventing of gasoline in clayey soil: A case history

International Nuclear Information System (INIS)

Loo, W.W.; Wang, I.S.; Fan, J.

1994-01-01

This paper presents a case history on the bioventing of gasoline in soil with electrokinetic enhancement. The gasoline in soil was related to a 10,000-gallon underground storage tank spill, San Diego, California. The gasoline soil plume covers an area of about 2,400 square feet and to a depth of about 30 feet. The upper 15 feet of the soil plume consists of highly conductive marine clay. The lower 15 feet of the soil plume consists of dense cemented conglomerate sandstone. The gasoline concentration in the soil plume range from 100 to 2,200 mg/Kg(ppm) and the target cleanup level is below 100 ppm. Total gasoline in soil plume is estimated at about 1,000 pounds of gasoline in about 3,500 tons of soil. The soil remediation effort was completed after about 90 days of treatment. The concentration of gasoline in soil after treatment was way below the proposed cleanup level of less than 100 mg/Kg(ppm). The cost of treatment is about $50 per ton for this advanced soil treatment process which provides a cost effective solution to this soil plume with minimum disruption to business operation at the facility

Cryogenic high current discharges

International Nuclear Information System (INIS)

Meierovich, B.E.

1994-01-01

Z-pinches formed from frozen deuterium fibers by a rapidly rising current have enhanced stability and high neutron yield. The efforts to understand the enhanced stability and neutron yield on the basis of classical picture of Bennett equilibrium of the current channel has not given satisfactory results. The traditional approach does not take into account the essential difference between the frozen deuterium fiber Z-pinches and the usual Z-pinches such as exploding wires or classical gas-puffed Z-pinches. The very low temperature of the fiber atoms (10 K), together with the rapidly rising current, result in the coexistence of a high current channel with unionized fiber atoms for a substantial period of time. This phenomena lasts during the risetime. This approach takes into account the difference of the breakdown in a dielectric deuterium fiber and the breakdown in a metallic wire. This difference is essential to the understanding of specific features of cryogenic high current discharges. Z-pinches in frozen deuterium fibers should be considered as a qualitatively new phenomenon on the boundary of cryogenic and high current physics. It is a start of a new branch in plasma physics: the physics of cryogenic high current discharges

Electrokinetic Supercapacitor for Simultaneous Harvesting and Storage of Mechanical Energy.

Science.gov (United States)

Yang, Peihua; Qu, Xiaopeng; Liu, Kang; Duan, Jiangjiang; Li, Jia; Chen, Qian; Xue, Guobin; Xie, Wenke; Xu, Zhimou; Zhou, Jun

2018-03-07

Energy harvesting and storage are two distinct processes that are generally achieved using two separated parts based on different physical and chemical principles. Here we report a self-charging electrokinetic supercapacitor that directly couples the energy harvesting and storage processes into one device. The device consists of two identical carbon nanotube/titanium electrodes, separated by a piece of anodic aluminum oxide nanochannels membrane. Pressure-driven electrolyte flow through the nanochannels generates streaming potential, which can be used to charge the capacitive electrodes, accomplishing simultaneous energy generation and storage. The device stores electric charge density of 0.4 mC cm -2 after fully charging under pressure of 2.5 bar. This work may offer a train of thought for the development of a new type of energy unit for self-powered systems.

High-voltage high-current triggering vacuum switch

International Nuclear Information System (INIS)

Alferov, D.F.; Bunin, R.A.; Evsin, D.V.; Sidorov, V.A.

2012-01-01

Experimental investigations of switching and breaking capacities of the new high current triggered vacuum switch (TVS) are carried out at various parameters of discharge current. It has been shown that the high current triggered vacuum switch TVS can switch repeatedly a current from units up to ten kiloampers with duration up to ten millisecond [ru

Development of Self-Potential Tomography for Early Warning System of rainfall induced Landslides: Electro-kinetic Effects and Sandbox Experiments

Science.gov (United States)

Hattori, K.; Yamazaki, T.; Terajima, T.; Huang, Q.

2017-12-01

Electro-kinetic effects is one of the possible mechanism for ULF electromagnetic phenomena preceeding landlisdes and large earthquakes. To understand general tendencies of electromagnetic changes related to electro-kinetic effects, we struggle with the integrated research to clarify the coupling among hydrological, geotechnical, and electromagnetic changes. Our final goal is to understand the ULF elecromagnetic phenomena in order to develop a simple technology for earthquake monitoring/forecasting. So, in this paper, we first show the observed waveforms possibly related to the Boso slow slip events in 2003 and 2007 and indoor landslide experiments with artificial rainfall. Then, numerical computations on the self-potential variation by the simulated groundwater flow, and compare the results with those observed by laboratory experiments. In the result, the simulated self-potential variation is consistent with observed one. FInally, we developed self-potential tomography to estimate the ground water condition. And we also characterize the pressure from the self-potential data, and compare the result with observed pressure head that is measured by pore-pressure gauge and found that the inverted pressure head is consistent with observed one. In addition, we apply the self-potential data observed by the flume test. The estimated pressure head from observed self-potential data shows the consistency with observed pressure head. And estimated pressure head also show the characteristic distribution before the landslide occurred. These facts are highly suggestive in effectiveness of the self-potential tomography to monitor groundwater changes associated with landslide. The details will be given in our presentation.

Improved isolation of cadmium from paddy soil by novel technology based on pore water drainage with graphite-contained electro-kinetic geosynthetics.

Science.gov (United States)

Tang, Xianqiang; Li, Qingyun; Wang, Zhenhua; Hu, Yanping; Hu, Yuan; Scholz, Miklas

2018-03-10

Novel soil remediation equipment based on electro-kinetic geosynthetics (EKG) was developed for in situ isolation of metals from paddy soil. Two mutually independent field plot experiments A and B (with and without electric current applied) were conducted. After saturation using ferric chloride (FeCl 3 ) and calcium chloride (CaCl 2 ), soil water drainage capacity, soil cadmium (Cd) removal performance, energy consumption as well as soil residual of iron (Fe) and chloride (Cl) were assessed. Cadmium dissolved in the soil matrix and resulted in a 100% increase of diethylenetriamine-pentaacetic acid (DTPA) extracted phyto-available Cd. The total soil Cd content reductions were 15.20% and 26.58% for groups A and B, respectively, and electric field applications resulted in a 74.87% increase of soil total Cd removal. The electric energy consumption was only 2.17 kWh/m 3 for group B. Drainage by gravity contributed to > 90% of the overall soil dewatering capacity. Compared to conventional electro-kinetic technology, excellent and fast soil water drainage resulted in negligible hydrogen ion (H + ) and hydroxide ion (OH - ) accumulation at nearby electrode zones, which addressed the challenge of anode corrosion and cathode precipitation of soil metals. External addition of FeCl 3 and CaCl 2 caused soil Fe and Cl residuals and led to 4.33-7.59% and 139-172% acceptable augments in soil total Fe and Cl content, correspondingly, if compared to original untreated soils. Therefore, the novel soil remediation equipment developed based on EKG can be regarded as a promising new in situ technology for thoroughly isolating metals from large-scale paddy soil fields.

Bacterial surface appendages strongly impact nanomechanical and electrokinetic properties of Escherichia coli cells subjected to osmotic stress.

Directory of Open Access Journals (Sweden)

Grégory Francius

Full Text Available The physicochemical properties and dynamics of bacterial envelope, play a major role in bacterial activity. In this study, the morphological, nanomechanical and electrohydrodynamic properties of Escherichia coli K-12 mutant cells were thoroughly investigated as a function of bulk medium ionic strength using atomic force microscopy (AFM and electrokinetics (electrophoresis. Bacteria were differing according to genetic alterations controlling the production of different surface appendages (short and rigid Ag43 adhesins, longer and more flexible type 1 fimbriae and F pilus. From the analysis of the spatially resolved force curves, it is shown that cells elasticity and turgor pressure are not only depending on bulk salt concentration but also on the presence/absence and nature of surface appendage. In 1 mM KNO(3, cells without appendages or cells surrounded by Ag43 exhibit large Young moduli and turgor pressures (∼700-900 kPa and ∼100-300 kPa respectively. Under similar ionic strength condition, a dramatic ∼50% to ∼70% decrease of these nanomechanical parameters was evidenced for cells with appendages. Qualitatively, such dependence of nanomechanical behavior on surface organization remains when increasing medium salt content to 100 mM, even though, quantitatively, differences are marked to a much smaller extent. Additionally, for a given surface appendage, the magnitude of the nanomechanical parameters decreases significantly when increasing bulk salt concentration. This effect is ascribed to a bacterial exoosmotic water loss resulting in a combined contraction of bacterial cytoplasm together with an electrostatically-driven shrinkage of the surface appendages. The former process is demonstrated upon AFM analysis, while the latter, inaccessible upon AFM imaging, is inferred from electrophoretic data interpreted according to advanced soft particle electrokinetic theory. Altogether, AFM and electrokinetic results clearly demonstrate the

Measurement technology of RF interference current in high current system

Science.gov (United States)

Zhao, Zhihua; Li, Jianxuan; Zhang, Xiangming; Zhang, Lei

2018-06-01

Current probe is a detection method commonly used in electromagnetic compatibility. With the development of power electronics technology, the power level of power conversion devices is constantly increasing, and the power current of the electric energy conversion device in the electromagnetic launch system can reach 10kA. Current probe conventionally used in EMC (electromagnetic compatibility) detection cannot meet the test requirements on high current system due to the magnetic saturation problem. The conventional high current sensor is also not suitable for the RF (Radio Frequency) interference current measurement in high current power device due to the high noise level in the output of active amplifier. In this paper, a passive flexible current probe based on Rogowski coil and matching resistance is proposed that can withstand high current and has low noise level, to solve the measurement problems of interference current in high current power converter. And both differential mode and common mode current detection can be easily carried out with the proposed probe because of the probe's flexible structure.

Integration of Multiplexed Microfluidic Electrokinetic Concentrators with a Morpholino Microarray via Reversible Surface Bonding for Enhanced DNA Hybridization.

Science.gov (United States)

Martins, Diogo; Wei, Xi; Levicky, Rastislav; Song, Yong-Ak

2016-04-05

We describe a microfluidic concentration device to accelerate the surface hybridization reaction between DNA and morpholinos (MOs) for enhanced detection. The microfluidic concentrator comprises a single polydimethylsiloxane (PDMS) microchannel onto which an ion-selective layer of conductive polymer poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) ( PSS) was directly printed and then reversibly surface bonded onto a morpholino microarray for hybridization. Using this electrokinetic trapping concentrator, we could achieve a maximum concentration factor of ∼800 for DNA and a limit of detection of 10 nM within 15 min. In terms of the detection speed, it enabled faster hybridization by around 10-fold when compared to conventional diffusion-based hybridization. A significant advantage of our approach is that the fabrication of the microfluidic concentrator is completely decoupled from the microarray; by eliminating the need to deposit an ion-selective layer on the microarray surface prior to device integration, interfacing between both modules, the PDMS chip for electrokinetic concentration and the substrate for DNA sensing are easier and applicable to any microarray platform. Furthermore, this fabrication strategy facilitates a multiplexing of concentrators. We have demonstrated the proof-of-concept for multiplexing by building a device with 5 parallel concentrators connected to a single inlet/outlet and applying it to parallel concentration and hybridization. Such device yielded similar concentration and hybridization efficiency compared to that of a single-channel device without adding any complexity to the fabrication and setup. These results demonstrate that our concentrator concept can be applied to the development of a highly multiplexed concentrator-enhanced microarray detection system for either genetic analysis or other diagnostic assays.

High-voltage, high-current, solid-state closing switch

Science.gov (United States)

Focia, Ronald Jeffrey

2017-08-22

A high-voltage, high-current, solid-state closing switch uses a field-effect transistor (e.g., a MOSFET) to trigger a high-voltage stack of thyristors. The switch can have a high hold-off voltage, high current carrying capacity, and high time-rate-of-change of current, di/dt. The fast closing switch can be used in pulsed power applications.

Removal of uranium from contaminated soil using indoor electrokinetic decontamination

International Nuclear Information System (INIS)

Gye-Nam Kim; Ilgook Kim; Seung-Soo Kim; Jong-Won Choi

2016-01-01

Indoor electrokinetic decontamination equipment was manufactured to treat 1.2 tons of uranium-contaminated soil. For a reduction of waste electrolyte and metal oxide, waste electrolyte was reused and the optimum pH was adjusted to minimize metal oxide volume in the cathode chamber. It was found that the optimum pH of the waste electrolyte in a cathode chamber was below 2.35 at 25 deg C. When the initial uranium concentrations in the soils were 7.0-27.0 Bq/g, the reuse periods of waste electrolyte required for uranium concentrations in the soils to reach below 5.0 Bq/g were 5-25 days. In addition, when the initial concentrations in the soils were 7.0-20.0 Bq/g, the periods required to reach below the clearance concentration level were 25-40 days.

Enantioresolution in electrokinetic chromatography-complete filling technique using sulfated gamma-cyclodextrin. Software-free topological anticipation.

Science.gov (United States)

Escuder-Gilabert, Laura; Martín-Biosca, Yolanda; Medina-Hernández, María José; Sagrado, Salvador

2016-10-07

Few papers have tried to predict the resolution ability of chiral selectors in capillary electrophoresis for the separation of the enantiomers of chiral compounds. In a previous work, we have used molecular information available on-line to establish enantioresolution levels of basic compounds using highly sulfated β-CD (HS-β-CD) as chiral selector in electrokinetic chromatography-complete filling technique (EKC-CFT). The present study is a continuation of this previous work, introducing some novelties. In this work, the ability of sulfated γ-cyclodextrin (S-γ-CD) as chiral selector in EKC-CFT is modelled for the first time. Thirty-three structurally unrelated cationic and neutral compounds (drugs and pesticides) are studied. Categorical enantioresolution levels (RsC, 0 or 1) are assigned from experimental enantioresolution values obtained at different S-γ-CD concentrations. Novel topological parameters connected to the chiral carbon (C * -parameters) are introduced. Four C * -parameters and a topological parameter of the whole molecule (aromatic atom count) are the most important variables according to a discriminant partial least squares-variable selection process. It suggests the preponderance of the topology adjacent to the chiral carbon to anticipate the RsC levels. A software-free anticipation protocol for new molecules is proposed. Over the current set of molecules evaluated, 100% of correct anticipations (resolved and non-resolved compounds) are obtained, while anticipation of some compounds remains undetermined. A criterion is introduced to alert on compounds which should not be anticipated. Copyright © 2016 Elsevier B.V. All rights reserved.

Self-Consistent Approach to Global Charge Neutrality in Electrokinetics: A Surface Potential Trap Model

Directory of Open Access Journals (Sweden)

Li Wan

2014-03-01

Full Text Available In this work, we treat the Poisson-Nernst-Planck (PNP equations as the basis for a consistent framework of the electrokinetic effects. The static limit of the PNP equations is shown to be the charge-conserving Poisson-Boltzmann (CCPB equation, with guaranteed charge neutrality within the computational domain. We propose a surface potential trap model that attributes an energy cost to the interfacial charge dissociation. In conjunction with the CCPB, the surface potential trap can cause a surface-specific adsorbed charge layer σ. By defining a chemical potential μ that arises from the charge neutrality constraint, a reformulated CCPB can be reduced to the form of the Poisson-Boltzmann equation, whose prediction of the Debye screening layer profile is in excellent agreement with that of the Poisson-Boltzmann equation when the channel width is much larger than the Debye length. However, important differences emerge when the channel width is small, so the Debye screening layers from the opposite sides of the channel overlap with each other. In particular, the theory automatically yields a variation of σ that is generally known as the “charge regulation” behavior, attendant with predictions of force variation as a function of nanoscale separation between two charged surfaces that are in good agreement with the experiments, with no adjustable or additional parameters. We give a generalized definition of the ζ potential that reflects the strength of the electrokinetic effect; its variations with the concentration of surface-specific and surface-nonspecific salt ions are shown to be in good agreement with the experiments. To delineate the behavior of the electro-osmotic (EO effect, the coupled PNP and Navier-Stokes equations are solved numerically under an applied electric field tangential to the fluid-solid interface. The EO effect is shown to exhibit an intrinsic time dependence that is noninertial in its origin. Under a step-function applied

Determination of the distribution constants of aromatic compounds and steroids in biphasic micellar phosphonium ionic liquid/aqueous buffer systems by capillary electrokinetic chromatography

Czech Academy of Sciences Publication Activity Database

Lokajová, Jana; Railila, A.; King, A. W. T.; Wiedmer, S. K.

2013-01-01

Roč. 1308, Sep 20 (2013), s. 144-151 ISSN 0021-9673 Institutional support: RVO:61388963 Keywords : critical micelle concentration * electrokinetic chromatography * distribution constant * PeakMaster * phosphonium ionic liquid Subject RIV: CC - Organic Chemistry Impact factor: 4.258, year: 2013

Electrokinetic remediation of plutonium-contaminated nuclear site wastes: Results from a pilot-scale on-site trial

International Nuclear Information System (INIS)

Agnew, Kieran; Cundy, Andrew B.; Hopkinson, Laurence; Croudace, Ian W.; Warwick, Phillip E.; Purdie, Philip

2011-01-01

This paper examines the field-scale application of a novel low-energy electrokinetic technique for the remediation of plutonium-contaminated nuclear site soils, using soil wastes from the Atomic Weapons Establishment (AWE) Aldermaston site, Berkshire, UK as a test medium. Soils and sediments with varying composition, contaminated with Pu through historical site operations, were electrokinetically treated at laboratory-scale with and without various soil pre-conditioning agents. Results from these bench-scale trials were used to inform a larger on-site remediation trial, using an adapted containment pack with battery power supply. 2.4 m 3 (ca. 4 tonnes) of Pu-contaminated soil was treated for 60 days at a power consumption of 33 kW h/m 3 , and then destructively sampled. Radiochemical data indicate mobilisation of Pu in the treated soil, and migration (probably as a negatively charged Pu-citrate complex) towards the anodic compartment of the treatment cell. Soil in the cathodic zone of the treatment unit was remediated to a level below free-release disposal thresholds (1.7 Bq/g, or <0.4 Bq/g above background activities). The data show the potential of this method as a low-cost, on-site tool for remediation of radioactively contaminated soils and wastes which can be operated remotely on working sites, with minimal disruption to site infrastructure or operations.

Insights into head-column field-amplified sample stacking: Part I. Detailed study of electrokinetic injection of a weak base across a short water plug

Czech Academy of Sciences Publication Activity Database

Šesták, Jozef; Thormann, W.

2017-01-01

Roč. 1502, FEB (2017), s. 51-61 ISSN 0021-9673 Institutional support: RVO:68081715 Keywords : capillary electrophoresis * electrokinetic injection * simulation Subject RIV: CB - Analytical Chemistry, Separation OBOR OECD: Analytical chemistry Impact factor: 3.981, year: 2016

Remediation of soil co-contaminated with petroleum and heavy metals by the integration of electrokinetics and biostimulation.

Science.gov (United States)

Dong, Zhi-Yong; Huang, Wen-Hui; Xing, Ding-Feng; Zhang, Hong-Feng

2013-09-15

Successful remediation of soil co-contaminated with high levels of organics and heavy metals is a challenging task, because that metal pollutants in soil can partially or completely suppress normal heterotrophic microbial activity and thus hamper biodegradation of organics. In this study, the benefits of integrating electrokinetic (EK) remediation with biodegradation for decontaminating soil co-contaminated with crude oil and Pb were evaluated in laboratory-scale experiments lasting for 30 days. The treated soil contained 12,500 mg/kg of total petroleum hydrocarbons (TPH) and 450 mg/kg Pb. The amendments of EDTA and Tween 80, together with a regular refreshing of electrolyte showed the best performance to remediate this contaminated soil. An important function of EDTA-enhanced EK treatment was to eliminate heavy metal toxicity from the soil, thus activating microbial degradation of oil. Although Tween 80 reduced current, it could serve as a second substrate for enhancing microbial growth and biodegradation. It was found that oil biodegradation degree and microbial numbers increased toward the anode and cathode. Microbial metabolism was found to be beneficial to metal release from the soil matrix. Under the optimum conditions, the soil Pb and TPH removal percentages after 30 days of running reached 81.7% and 88.3%, respectively. After treatment, both the residual soil Pb and TPH concentrations met the requirement of the Chinese soil environmental quality standards. Copyright © 2013 Elsevier B.V. All rights reserved.

High-Average, High-Peak Current Injector Design

CERN Document Server

Biedron, S G; Virgo, M

2005-01-01

There is increasing interest in high-average-power (>100 kW), um-range FELs. These machines require high peak current (~1 kA), modest transverse emittance, and beam energies of ~100 MeV. High average currents (~1 A) place additional constraints on the design of the injector. We present a design for an injector intended to produce the required peak currents at the injector, eliminating the need for magnetic compression within the linac. This reduces the potential for beam quality degradation due to CSR and space charge effects within magnetic chicanes.

High PRF high current switch

Science.gov (United States)

Moran, Stuart L.; Hutcherson, R. Kenneth

1990-03-27

A triggerable, high voltage, high current, spark gap switch for use in pu power systems. The device comprises a pair of electrodes in a high pressure hydrogen environment that is triggered by introducing an arc between one electrode and a trigger pin. Unusually high repetition rates may be obtained by undervolting the switch, i.e., operating the trigger at voltages much below the self-breakdown voltage of the device.

Insights into head-column field-amplified sample stacking: Part II. Study of the behavior of the electrophoretic system after electrokinetic injection of cationic compounds across a short water plug.

Science.gov (United States)

Šesták, Jozef; Thormann, Wolfgang

2017-08-25

Part I on head-column field-amplified sample stacking comprised a detailed study of the electrokinetic injection of a weak base across a short water plug into a phosphate buffer at low pH. The water plug is converted into a low conductive acidic zone and cationic analytes become stacked at the interface between this and a newly formed phosphoric acid zone. The fundamentals of electrokinetic processes occurring thereafter were studied experimentally and with computer simulation and are presented as part II. The configuration analyzed represents a discontinuous buffer system. Computer simulation revealed that the phosphoric acid zone at the plug-buffer interface becomes converted into a migrating phosphate buffer plug which corresponds to the cationically migrating system zone of the phosphate buffer system. Its mobility is higher than that of the analytes such that they migrate behind the system zone in a phosphate buffer comparable to the applied background electrolyte. The temporal behaviour of the current and the conductivity across the water plug were monitored and found to reflect the changes in the low conductivity plug. Determination of the buffer flow in the capillary revealed increased pumping caused by the mismatch of electroosmosis within the low conductivity plug and the buffer. This effect becomes elevated with increasing water plug length. For plug lengths up to 1% of the total column length the flow quickly drops to the electroosmotic flow of the buffer and simulations with experimentally determined current and flow values predict negligible band dispersion and no loss of resolution for both low and large molecular mass components. Copyright © 2017 Elsevier B.V. All rights reserved.

Acupuncture Injection Combined with Electrokinetic Injection for Polydimethylsiloxane Microfluidic Devices

Directory of Open Access Journals (Sweden)

Ji Won Ha

2017-01-01

Full Text Available We recently reported acupuncture sample injection that leads to reproducible injection of nL-scale sample segments into a polydimethylsiloxane (PDMS microchannel for microchip capillary electrophoresis. The advantages of the acupuncture injection in microchip capillary electrophoresis include capability of minimizing sample loss and voltage control hardware and capability of introducing sample plugs into any desired position of a microchannel. However, the challenge in the previous study was to achieve reproducible, pL-scale sample injections into PDMS microchannels. In the present study, we introduce an acupuncture injection technique combined with electrokinetic injection (AICEI technique to inject pL-scale sample segments for microchip capillary electrophoresis. We carried out the capillary zone electrophoresis (CZE separation of FITC and fluorescein, and the mixture of 10 μM FITC and 10 μM fluorescein was separated completely by using the AICEI method.

Ferric iron remediation and stabilisation (firs) - developing a new robust electrokinetic remediation technique for heavy metal and radionuclide contaminated sites

International Nuclear Information System (INIS)

Faulkner, D.; Hopkinson, L.; Cundy, A.

2005-01-01

Electrokinetic remediation is an emerging technology that has generated considerable interest as a technique for the in-situ remediation of contaminated clay-rich soils and sediments. Despite promising experimental results, however, at present there is no standardised universal electrokinetic soil/sediment remediation approach. Many of the current technologies are technically complex and energy intensive, and geared towards the removal of 90% or more of specific contaminants, under very specific field or laboratory-based conditions. However, in the real environment a low-tech, low-energy contaminant reduction / containment technique may be more appropriate and realistic. Such a technique, FIRS (Ferric Iron Remediation and Stabilisation), is discussed here. The FIRS technique involves the application of a low magnitude (typically less than 0.2 V/cm) direct electric potential between two or more sacrificial, iron-rich, electrodes emplaced either side of a contaminated soil or sediment. The electric potential is used to generate a strong pH (and Eh) gradient within the soil column (pH 2 - 13), which acts to re-mobilize contaminants in the treated soil, and force the precipitation of an impermeable, sorptive iron-rich barrier or 'pan' in the soil between the electrodes. Geochemical data from bench-scale treatment cells indicate that the FIRS technique can significantly reduce the concentration of a range of heavy metals and radionuclides in contaminated soils, by remobilization of contaminants followed by precipitation on, or around, the iron-rich barrier generated by the technique. In addition, arsenic seems highly amenable to the FIRS treatment, due to its solubility under the high pH conditions generated near to the cathode, and its marked geochemical affinity with the freshly precipitated iron oxides and oxy-hydroxides in the iron barrier. Geotechnical tests indicate that the iron barrier produced by the technique is practically impervious (permeability 10 -9 m

Phospholipid bilayer affinities and solvation characteristics by electrokinetic chromatography with a nanodisc pseudostationary phase.

Science.gov (United States)

Penny, William M; Steele, Harmen B; Ross, J B Alexander; Palmer, Christopher P

2017-03-01

Phospholipid bilayer nanodiscs composed of 1,2-dimyristoyl-sn-glycero-3-phosphocholine and synthetic maleic acid-styrene copolymer belts have been introduced as a pseudostationary phase (PSP) in electrokinetic chromatography and demonstrated good performance. The nanodiscs provide a suitable migration range and high theoretical plate counts. Using this nanodisc pseudostationary phase, the affinity of the bilayer structure for probe solutes was determined and characterized. Good correlation is observed between retention factors and octanol water partition coefficients for particular categories of solutes, but the general correlation is weak primarily because the nanodiscs show stronger affinity than octanol for hydrogen bond donors. This suggests that a more appropriate application of this technology is to measure and characterize interactions between solutes and lipid bilayers directly. Linear solvation energy relationship analysis of the nanodisc-solute interactions in this study demonstrates that the nanodiscs provide a solvation environment with low cohesivity and weak hydrogen bond donating ability, and provide relatively strong hydrogen bond acceptor strength. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrokinetic aspects of water filtration by AlOOH-coated siliceous particles with nanoscale roughness

Directory of Open Access Journals (Sweden)

Leonid A. Kaledin

2017-03-01

Full Text Available The vast majority of analytical and numerical models developed to explain pressure-driven electrokinetic phenomena assume that the local electrical double layer field over heterogenious surfaces is independent of the flow field and described by the Poison-Boltzman equation. However, for pressure-driven flow over a surface with heterogeneous patches with combined microscale and nanoscale structures the local electrical double layer fields are different above the patch and in the region between the patches. The nonuniform surface charge produces distortions in the equilibrium electrostatic field. The characteristic symptom of field distortion is the generation of flow velocities in all three coordinate directions, including a circulation pattern perpendicular to the main flow axis therefore severely distorting the Poisson-Boltzmann double layer. The result is an exceptionally high microbes and ions removal efficiencies from aqueous suspension by the alumina’s surfaces with combined microscale and nanoscale structures that strongly suggests existence of a coupling effect of the local electrical double layer (EDL field with the local flow field.

A laboratory feasibility study on electrokinetic injection of nutrients on an organic, tropical, clayey soil.

Science.gov (United States)

Schmidt, Celina A B; Barbosa, Maria Claudia; de Almeida, Márcio de S S

2007-05-17

Based on the results of an environmental investigation program, carried out on an oil production field at Brazilian Northeast, a contamination diagnosis was made. The field was contaminated by crude oil and saline production water and the use of in situ electrokinetic bioremediation techniques in situ were suggested for the remediation of the contaminated site. The analyzed soil is a very humid clayey silt, with high plasticity, high electrical conductivity, low hydraulic conductivity, low density, large buffering capacity and high cation exchange capacity. The soil is rich in organic matter and poor in nitrogen. The removal of the contaminated soil for ex situ treatment is not advisable in contaminated studied area due to the restrictions imposed by local environmental authority, as well as operational impediments caused by the presence of vegetation and flooded conditions. After the diagnosis a program of laboratory tests was carried out on soil from the location in an electrical cell which was developed for this purpose. The study showed the feasibility of injecting nitrate and ammonium to this kind of soil, though the injection of phosphorous did not prove to be successful. It is recommended to control variations changes in pH, caused by the application of electrokinesis, in order not to harm the biodegradation process.

High current plasma electron emitter

International Nuclear Information System (INIS)

Fiksel, G.; Almagri, A.F.; Craig, D.

1995-07-01

A high current plasma electron emitter based on a miniature plasma source has been developed. The emitting plasma is created by a pulsed high current gas discharge. The electron emission current is 1 kA at 300 V at the pulse duration of 10 ms. The prototype injector described in this paper will be used for a 20 kA electrostatic current injection experiment in the Madison Symmetric Torus (MST) reversed-field pinch. The source will be replicated in order to attain this total current requirement. The source has a simple design and has proven very reliable in operation. A high emission current, small size (3.7 cm in diameter), and low impurity generation make the source suitable for a variety of fusion and technological applications

Bench- and field-scale evaluation of chromium and cadmium extraction by electrokinetics

International Nuclear Information System (INIS)

Gent, David B.; Bricka, R. Mark; Alshawabkeh, Akram N.; Larson, Steven L.; Fabian, Gene; Granade, Steve

2004-01-01

The results of bench-scale laboratory tests and in situ, pilot-scale demonstration of electrokinetic extraction of chromium and cadmium from contaminated soil are presented. The laboratory tests were conducted using 10 cm long samples under current density of 5 A/m 2 for 1200 h. Tests were conducted with and without citric acid amendment at the cathode. The results showed that citric acid improved extraction, especially in the sections near the cathode. However, processing was not enough to result in complete cleanup. The field demo was conducted at the Naval Air Weapon Station (NAWS), Point Mugu, California. Three cathodes were centered between six anodes. The anode-cathode spacing was 4.45 m (15 ft). Constant voltage of 60 V (∼13 V/m) was applied for 20 days and then was reduced to 45 V (10 V/m) for 6 months. Citric acid was used to maintain the cathode pH at 4. After 6 months of treatment, 78% of the soil volume has been cleared of chromium or treated to below natural background levels. The results also indicated that 70% of the soil between the electrodes had been cleared of cadmium contamination. A comparison between the bench-scale and field demo showed that the field process was more effective than the lab tests. This indicated that small sample size will induce a negative effect on the efficiency of the process due to an increased impact of the boundaries on the overall process

Scale-up of the electrokinetic fence technology for the removal of pesticides. Part II: Does size matter for removal of herbicides?

Science.gov (United States)

López-Vizcaíno, R; Risco, C; Isidro, J; Rodrigo, S; Saez, C; Cañizares, P; Navarro, V; Rodrigo, M A

2017-01-01

This work reports results of the application of electrokinetic fence technology in a 32 m 3 -prototype which contains soil polluted with 2,4-D and oxyfluorfen, focusing on the evaluation of the mechanisms that describe the removal of these two herbicides and comparing results to those obtained in smaller plants: a pilot-scale mockup (175 L) and a lab-scale soil column (1 L). Results show that electric heating of soil (coupled with the increase in the volatility) is the key to explain the removal of pollutants in the largest scale facility while electrokinetic transport processes are the primary mechanisms that explain the removal of herbicides in the lab-scale plant. 2-D and 3-D maps of the temperature and pollutant concentrations are used in the discussion of results trying to give light about the mechanisms and about how the size of the setup can lead to different conclusions, despite the same processes are occurring in the soil. Copyright © 2016 Elsevier Ltd. All rights reserved.

Recovery of Drug Delivery Nanoparticles from Human Plasma Using an Electrokinetic Platform Technology.

Science.gov (United States)

Ibsen, Stuart; Sonnenberg, Avery; Schutt, Carolyn; Mukthavaram, Rajesh; Yeh, Yasan; Ortac, Inanc; Manouchehri, Sareh; Kesari, Santosh; Esener, Sadik; Heller, Michael J

2015-10-01

The effect of complex biological fluids on the surface and structure of nanoparticles is a rapidly expanding field of study. One of the challenges holding back this research is the difficulty of recovering therapeutic nanoparticles from biological samples due to their small size, low density, and stealth surface coatings. Here, the first demonstration of the recovery and analysis of drug delivery nanoparticles from undiluted human plasma samples through the use of a new electrokinetic platform technology is presented. The particles are recovered from plasma through a dielectrophoresis separation force that is created by innate differences in the dielectric properties between the unaltered nanoparticles and the surrounding plasma. It is shown that this can be applied to a wide range of drug delivery nanoparticles of different morphologies and materials, including low-density nanoliposomes. These recovered particles can then be analyzed using different methods including scanning electron microscopy to monitor surface and structural changes that result from plasma exposure. This new recovery technique can be broadly applied to the recovery of nanoparticles from high conductance fluids in a wide range of applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Surfactant-free microemulsion electrokinetic chromatography (SF-MEEKC) with UV and MS detection - a novel approach for the separation and ESI-MS detection of neutral compounds.

Science.gov (United States)

Mohorič, Urška; Beutner, Andrea; Krickl, Sebastian; Touraud, Didier; Kunz, Werner; Matysik, Frank-Michael

2016-12-01

Microemulsion electrokinetic chromatography (MEEKC) is a powerful tool to separate neutral species based on differences in their hydrophobic and hydrophilic properties. However, as a major drawback the conventionally used SDS based microemulsions are not compatible with electrospray ionization mass spectrometry (ESI-MS). In this work, a surfactant-free microemulsion (SFME) consisting of water, ethanol, and 1-octanol is used for surfactant-free microemulsion electrokinetic chromatography (SF-MEEKC). Ammonium acetate was added to the SFME enabling electrophoretic separations. The stability of SFMEs containing ammonium acetate was investigated using small-angle X-ray scattering and dynamic light scattering. A method for the separation of a model system of hydrophobic and hydrophilic neutral vitamins, namely the vitamins B 2 and D 3 , and the cationic vitamin B 1 was developed using UV/VIS detection. The influence of the ammonium acetate concentration on the separation performance was studied in detail. The method was characterized concerning reproducibility of migration times and peak areas and concerning the linearity of the calibration data. Furthermore, SF-MEEKC was coupled to ESI-MS investigating the compatibility between SFMEs and the ESI process. The signal intensities of ESI-MS measurements of the model analytes were comparable for SFMEs and aqueous systems. Finally, the vitamin D 3 content of a drug treating vitamin D 3 deficiency was determined by SF-MEEKC coupled to ESI-MS using 25-hydroxycholecalciferol as an internal standard. Graphical abstract The concept of surfactant-free microemulsion electrokinetic chromatography coupled to electrospray ionization mass spectrometry.

Electrokinetic transport behavior of phenol in upper Permian soils

Energy Technology Data Exchange (ETDEWEB)

Haus, R.; Zorn, R.; Czurda, K.; Ruthe, H. [Dept. of Applied Geology, Univ. Karlsruhe (Germany)

2001-07-01

Electrokinetic experiments with upper Permian, phenol contaminated soils ('Solaris'-area Chemnitz) were performed. Bench scale results show the successful removal of phenol. The developing soil-pH during electroremediation tests is found to affect the transport behavior of phenol strongly. If buffer solutions are used at the electrode compartments, phenol could be removed from the soils. By neutralizing the generating hydrogen ions at the anode reservoir the hydroxyl ions developing at the cathode by the electrolysis of water enter the soil and propagate to the anode by increasing the soil pH. The pH dependent dehydroxylation of phenol promotes the electromigration of negative charged phenolate ions from the cathode to the anode. At the anode the coupling of phenoxyl-radicals supports the formation of non toxic, water insoluble polyoxyphenylene by electro-polymerization. In the case of buffering the pH at the cathode uncharged phenol is transported by electroosmosis from the anode to the cathode because of the nonexisting base front and the unhindered production of hydrogen ions at the anode. (orig.)

Removal of contaminants from fine grained soils using electrokinetic (EK) flushing. Final report, September 30, 1987--June 30, 1993

Energy Technology Data Exchange (ETDEWEB)

Reed, B.E.; Berg, M.T.

1993-10-01

Recently, attention has focused on developing cost effective techniques to remove inorganic contaminants from soils in-situ. For most in-situ techniques hydraulic pressure is used to disperse the chemical additives and collect the contaminated groundwater. In-situ treatment technologies have had success at sites containing sandy soils but have not shown much promise for soils with large amounts of clay and silt. This is due primarily to difficulty in transporting groundwater, contaminants, and chemical additives through the subsurface. Unfortunately, soils high in clay and silt are known to sequester large quantities of inorganic and organic contaminants. Thus, soils having low hydraulic conductivity`s are generally efficient in sequestering pollutants but are resistant to standard in-situ remediation techniques because of the difficulty in transporting groundwater and contaminants. A candidate technology for the in-situ remediation of low permeability soils is electrokinetic (EK) soil flushing. In EK soil flushing, groundwater and contaminants are transported under an a plied voltage. The transport of groundwater electroosmotically does not depend directly on the soil`s hydraulic conductivity. Thus, soils that would otherwise require excavation and treatment can be remediated in-situ if electrokinetics is used as the driving force for liquid and contaminant transport. This report details the results from work conducted on the use of EK soil flushing to remediate a fine grained soil contaminated with lead. The first portion of the experimental work entailed soil collection and characterization, soil adsorption and desorption of lead, and EK reactor construction and testing. The second phase of the research consisted of investigating the efficacy of using EK soil flushing on an actual soil using bench-scale EK reactors. For the second phase of the research the affect of initial conditions on the efficiency of EK soil flushing was studied.

Electrokinetic soil decontamination - summary of results of various studies in laboratory, bench-scale and field

Energy Technology Data Exchange (ETDEWEB)

Kutschan, B.; Wutzler, R.; Goldmann, T. [INTUS Inst. fuer Technologie und Umweltschutz e.V., Berlin (Germany)

2001-07-01

In electroremediation, contaminants are removed form soil and groundwater by the action of an electric potential applied across electrodes embedded in the contaminated medium. Driving the remediation are the electrokinetic phenomena of electro-osmosis, ion migration and electrophoresis. Other common physicochemical phenomena that are also present are diffusion, chemical reactions, hydrolysis (change of pH-value), ion exchange, complexation and others. The complex interactions between all these phenomena determine the processes. Important process parameters are transition rates, bulk liquid velocity, {zeta}-potential (Helmholtz-Smoluchowski-equation) and others. Some parameters are determined at laboratory-, bench- and field scale. (orig.)

Electrokinetic decontamination of concrete. Final report, August 3, 1993 - September 15, 1996

International Nuclear Information System (INIS)

1998-01-01

The ELECTROSORB reg-sign open-quotes Cclose quotes process is an electrokinetic process for decontaminating concrete. ELECTROSORB reg-sign open-quotes Cclose quotes uses a carpet-like extraction pad which is placed on the contaminated concrete surface. An electrolyte solution is circulated from a supporting module. This module keeps the electrolyte solution clean. The work is advancing through the engineering development stage with steady progress toward a full scale demonstration unit which will be ready for incorporation in the DOE Large Scale Demonstration Program by Summer 1997. A demonstration was carried out at the Mound Facility in Miamisburg, Ohio, in June 1996. Third party verification by EG ampersand G verified the effectiveness of the process. Results of this work and the development work that proceeded are described herein

Reduction of heavy metal from soil in Bakri Landfill, Muar, Johor by using Electrokinetic method

Science.gov (United States)

Azhar, ATS; Muhammad, E.; Zaidi, E.; Ezree, AM; Aziman, M.; Hazreek, ZAM; Nizam, ZM; Norshuhaila, MS

2017-08-01

The present study focuses on the contamination levels and distribution of heavy metals in soil samples located at Bakri Landfill area, Muar, Johor, Malaysia. The aim of this study is to determine the type of heavy metal elements that contribute towards soil contamination and to reduce them based on the comparison of elemental analysis between pre and post Electrokinetic (EK) processes. The ppm level concentration of elements in this landfill soil is measured by using X-ray Fluorescence analysis. ICP-MS testing was carried out for liquid samples analysis. There were two set of EK experiments conducted. In first phase, voltage was maintained at 3 Vcm-1 and prolonged for 3 hours, while second phase was operated at 1 Vcm-1 for 48 hours. In this work, distilled water was used as an electrolyte for the process and two identical copper foil were used as electrodes due to high electrical conductivity. The application of EK remediation revealed that successful removal of Rb and Ba elements in the soil were observed by 2-3%, however other heavy metals have not changed.

Characterization of high-current, high-temperature superconductor current lead elements

International Nuclear Information System (INIS)

Niemann, R.C.; Evans, D.J.; Fisher, B.L.; Brockenborough, W.E.; Roberts, P.R.; Rodenbush, A.J.

1996-08-01

The refrigeration loads of current leads for superconducting magnets can be significantly reduced by using high-temperature superconductor (HTS) leads. An HTS conductor type that is well suited for this application is a laminated sintered stack of HTS powder-in-tube (PIT) tapes. The superconducting elements are normally characterized by their manufacturer by measuring critical currents at 77 K in self field. Additional characterization, which correlates electrical performance at 77 K and at lower temperatures with applied magnetic fields, provides the current lead designer and conductor element manufacturer with critical information. For HTS conductor elements comprising a laminated and sintered stack of Bi-2223 PIT tapes having an alloyed Ag sheath, this characterization uses variable applied fields and operating temperatures

Integrated electrokinetics-adsorption remediation of saline-sodic soils: effects of voltage gradient and contaminant concentration on soil electrical conductivity.

Science.gov (United States)

Essa, Mohammed Hussain; Mu'azu, Nuhu Dalhat; Lukman, Salihu; Bukhari, Alaadin

2013-01-01

In this study, an integrated in situ remediation technique which couples electrokinetics with adsorption, using locally produced granular activated carbon from date palm pits in the treatment zones that are installed directly to bracket the contaminated soils at bench-scale, is investigated. Natural saline-sodic clay soil, spiked with contaminant mixture (kerosene, phenol, Cr, Cd, Cu, Zn, Pb, and Hg), was used in this study to investigate the effects of voltage gradient, initial contaminant concentration, and polarity reversal rate on the soil electrical conductivity. Box-Behnken Design (BBD) was used for the experimental design and response surface methodology (RSM) was employed to model, optimize, and interpret the results obtained using Design-Expert version 8 platform. The total number of experiments conducted was 15 with voltage gradient, polarity reversal rate, and initial contaminant concentration as variables. The main target response discussed in this paper is the soil electrical conductivity due to its importance in electrokinetic remediation process. Responses obtained were fitted to quadratic models whose R (2) ranges from 84.66% to 99.19% with insignificant lack of fit in each case. Among the investigated factors, voltage gradient and initial contaminant concentration were found to be the most significant influential factors.

Integrated Electrokinetics-Adsorption Remediation of Saline-Sodic Soils: Effects of Voltage Gradient and Contaminant Concentration on Soil Electrical Conductivity

Directory of Open Access Journals (Sweden)

Mohammed Hussain Essa

2013-01-01

Full Text Available In this study, an integrated in situ remediation technique which couples electrokinetics with adsorption, using locally produced granular activated carbon from date palm pits in the treatment zones that are installed directly to bracket the contaminated soils at bench-scale, is investigated. Natural saline-sodic clay soil, spiked with contaminant mixture (kerosene, phenol, Cr, Cd, Cu, Zn, Pb, and Hg, was used in this study to investigate the effects of voltage gradient, initial contaminant concentration, and polarity reversal rate on the soil electrical conductivity. Box-Behnken Design (BBD was used for the experimental design and response surface methodology (RSM was employed to model, optimize, and interpret the results obtained using Design-Expert version 8 platform. The total number of experiments conducted was 15 with voltage gradient, polarity reversal rate, and initial contaminant concentration as variables. The main target response discussed in this paper is the soil electrical conductivity due to its importance in electrokinetic remediation process. Responses obtained were fitted to quadratic models whose R2 ranges from 84.66% to 99.19% with insignificant lack of fit in each case. Among the investigated factors, voltage gradient and initial contaminant concentration were found to be the most significant influential factors.

Effects of electrokinetic treatment of a heavy metal contaminated soil on soil enzyme activities

International Nuclear Information System (INIS)

Cang Long; Zhou Dongmei; Wang Quanying; Wu Danya

2009-01-01

There is a growing concern on the potential application of a direct current (DC) electric field to soil for removing contaminants, but little is known about its impact on soil enzyme activities. This study investigated the change of enzyme activities of a heavy metal contaminated soil before and after electrokinetic (EK) treatments at lab-scale and the mechanisms of EK treatment to affect soil enzyme activities were explored. After treatments with 1-3 V cm -1 of voltage gradient for 420 h, soil pH, electrical conductivity (EC), soil organic carbon, dissolved organic carbon (DOC), soil heavy metal concentration and enzyme activities were analyzed. The results showed that the average removal efficiencies of soil copper were about 65% and 83% without and with pH control of catholyte, respectively, and all the removal efficiencies of cadmium were above 90%. The soil invertase and catalase activities increased and the highest invertase activity was as 170 times as the initial one. The activities of soil urease and acidic phosphatase were lower than the initial ones. Bivariate correlation analyses indicated that the soil invertase and acidic phosphatase activities were significantly correlated with soil pH, EC, and DOC at P < 0.05, but the soil urease activities had no correlation with the soil properties. On the other hand, the effects of DC electric current on solution invertase and catalase enzyme protein activities indicated that it had negative effect on solution catalase activity and little effect on solution invertase activity. From the change of invertase and catalase activities in soil and solution, the conclusion can be drawn that the dominant effect mechanism is the change of soil properties by EK treatments.

Effects of electrokinetic treatment of a heavy metal contaminated soil on soil enzyme activities

Energy Technology Data Exchange (ETDEWEB)

Cang Long [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Zhou Dongmei, E-mail: dmzhou@issas.ac.cn [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Wang Quanying; Wu Danya [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China)

2009-12-30

There is a growing concern on the potential application of a direct current (DC) electric field to soil for removing contaminants, but little is known about its impact on soil enzyme activities. This study investigated the change of enzyme activities of a heavy metal contaminated soil before and after electrokinetic (EK) treatments at lab-scale and the mechanisms of EK treatment to affect soil enzyme activities were explored. After treatments with 1-3 V cm{sup -1} of voltage gradient for 420 h, soil pH, electrical conductivity (EC), soil organic carbon, dissolved organic carbon (DOC), soil heavy metal concentration and enzyme activities were analyzed. The results showed that the average removal efficiencies of soil copper were about 65% and 83% without and with pH control of catholyte, respectively, and all the removal efficiencies of cadmium were above 90%. The soil invertase and catalase activities increased and the highest invertase activity was as 170 times as the initial one. The activities of soil urease and acidic phosphatase were lower than the initial ones. Bivariate correlation analyses indicated that the soil invertase and acidic phosphatase activities were significantly correlated with soil pH, EC, and DOC at P < 0.05, but the soil urease activities had no correlation with the soil properties. On the other hand, the effects of DC electric current on solution invertase and catalase enzyme protein activities indicated that it had negative effect on solution catalase activity and little effect on solution invertase activity. From the change of invertase and catalase activities in soil and solution, the conclusion can be drawn that the dominant effect mechanism is the change of soil properties by EK treatments.

Effects of sodium hypochlorite and high pH buffer solution in electrokinetic soil treatment on soil chromium removal and the functional diversity of soil microbial community

International Nuclear Information System (INIS)

Cang Long; Zhou Dongmei; Alshawabkeh, Akram N.; Chen Haifeng

2007-01-01

Effects of sodium hypochlorite (NaClO), applied as an oxidant in catholyte, and high pH buffer solution on soil Cr removal and the functional diversity of soil microbial community during enhanced electrokinetic treatments of a chromium (Cr) contaminated red soil are evaluated. Using pH control system to maintain high alkalinity of soil together with the use of NaClO increased the electrical conductivities of soil pore liquid and electroosmotic flux compared with the control (Exp-01). The pH control and NaClO improved the removal of Cr(VI) and total Cr from the soil. The highest removal percentages of soil Cr(VI) and total Cr were 96 and 72%, respectively, in Exp-04 when the pH value of the anolyte was controlled at 10 and NaClO was added in the catholyte. The alkaline soil environment and introduction of NaClO in the soil enhanced the desorption of Cr(VI) from the soil and promoted Cr(III) oxidation to mobile Cr(VI), respectively. However, the elevated pH and introduction of NaClO in the soil, which are necessary for improving the removal efficiency of soil Cr, resulted in a significantly adverse impact on the functional diversity of soil microbial community. It suggests that to assess the negative impact of extreme conditions for enhancing the extraction efficiencies of Cr on the soil properties and function is necessary

Electrokinetically Enhanced Delivery for ERD Remediation of Chlorinated Ethenes in a Fractured Limestone Aquifer

DEFF Research Database (Denmark)

Broholm, Mette Martina; Hyldegaard, Bente Højlund; With Nedergaard, Lærke

causing very long remediation timeframes. Electrokinetics (EK) offers some unique transport processes, which can potentially overcome the diffusion limitations in the matrix. A novel technology combines ERD and EK for enhanced delivery. The combined technology (EK-BIO) has shown promising results in clay....... Experimental work on EK-BIO in limestone was conducted in a laboratory setup with limestone cores. EK was demonstrated to be promising in establishing enhanced contact between the donor lactate, bacteria, and cis-DCE within the limestone matrix. Complete dechlorination is expected to take place in the matrix......, since back diffusion limitations in the limestone matrix are overcome. This is essential for the overall time perspective of a remediation in limestone aquifers....

Enantioseparation of palonosetron hydrochloride by micellar electrokinetic chromatography with sodium cholate as chiral selector.

Science.gov (United States)

Tian, Kan; Chen, Hongli; Tang, Jianghong; Chen, Xingguo; Hu, Zhide

2006-11-03

The enantioseparation of four stereoisomers of palonosetron hydrochloride by micellar electrokinetic chromatography using sodium cholate as chiral surfactant was described. Sodium cholate was shown to be effective in separating palonosetron hydrochloride stereoisomers. For method optimization, several parameters such as sodium cholate concentration, buffer pH and concentration, the types and concentration of organic modifiers and applied voltage, on the enantioseparation were evaluated and the optimum conditions were obtained as follows: 30 mM borate buffer (pH 9.40) containing 70 mM sodium cholate and 20% (v/v) methanol with an applied voltage of 20 kV. Under these conditions, baseline separation of palonosetron hydrochloride stereoisomers was achieved within 18 min.

Nanopore density effect of polyacrylamide gel plug on electrokinetic ion enrichment in a micro-nanofluidic chip

Science.gov (United States)

Wang, Jun-yao; Xu, Zheng; Li, Yong-kui; Liu, Chong; Liu, Jun-shan; Chen, Li; Du, Li-qun; Wang, Li-ding

2013-07-01

In this paper, the nanopore density effect on ion enrichment is quantitatively described with the ratio between electrophoresis flux and electroosmotic flow flux based on the Poisson-Nernst-Planck equations. A polyacrylamide gel plug is integrated into a microchannel to form a micro-nanofluidic chip. With the chip, electrokinetic ion enrichment is relatively stable and enrichment ratio of fluorescein isothiocyanate can increase to 600-fold within 120 s at the electric voltage of 300 V. Both theoretical research and experiments show that enrichment ratio can be improved through increasing nanopore density. The result will be beneficial to the design of micro-nanofluidic chips.

Design of high current bunching system and high power fast Faraday cup for high current LEBT at VECC

International Nuclear Information System (INIS)

Anuraag Misra, A.; Pandit, B.V.S.; Gautam Pal, C.

2011-01-01

A high current microwave ion source as described is currently operational at VECC. We are able to optimize 6.4 mA of proton current in the LEBT line of ion source. The cyclotron type of accelerators accept only a fraction of DC ion beam coming from ion source so a ion beam buncher is needed to increase the accepted current into the cyclotron. The buncher described in this paper is unique in its kind as it has to handle high beam loading power upto 400 W as it is designed to bunch few mA of proton beam currents at 80 keV beam energy. A sinusoidal quarter wave RF structure has been chosen to bunch the high current beam due to high Q achievable in comparison with other configurations. This buncher has been designed using CST Microwave studio 3D advanced code since the design frequency of our buncher is 42 MHz, we have provided the RF and vacuum window near the drift tube of buncher to avoid vacuum and multipacting problems and to keep maximum volume in air region. There is a provision of multipacting interlocks to shut off amplifier during multipacting. We have carried out a detailed electromagnetic and thermal design of the buncher in CST Microwave studio and simulated values of unloaded Q was calculated be 4000. We have estimated a power of 400 W to achieve gap (designed) voltage of 10 kV. This buncher is in advanced stage of fabrication. A high power fast Faraday cup is also designed to characterize the above mentioned high current bunching system. The fast Faraday cup is designed in 50 Ω coaxial geometry to transmit fast pulse of bunched ion beam. The design of Faraday cup was completed using ANSYS HFSS and a bandwidth of 1.75 GHz was achieved this faraday cup design was different from conventional Faraday cup design as we have designed the support and cooling lines at such a place on Faraday cup which do not disturb the electrical impedance of the cup. (author)

High current density ion source

International Nuclear Information System (INIS)

King, H.J.

1977-01-01

A high-current-density ion source with high total current is achieved by individually directing the beamlets from an electron bombardment ion source through screen and accelerator electrodes. The openings in these screen and accelerator electrodes are oriented and positioned to direct the individual beamlets substantially toward a focus point. 3 figures, 1 table

Recovery of copper and lead from waste printed circuit boards by supercritical water oxidation combined with electrokinetic process

International Nuclear Information System (INIS)

Xiu Furong; Zhang Fushen

2009-01-01

An effective and benign process for copper and lead recovery from waste printed circuit boards (PCBs) was developed. In the process, the PCBs was pre-treated in supercritical water, then subjected to electrokinetic (EK) process. Experimental results showed that supercritical water oxidation (SCWO) process was strong enough to decompose the organic compounds of PCBs, and XRD spectra indicated that copper and lead were oxidized into CuO, Cu 2 O and β-PbO 2 in the process. The optimum SCWO treatment conditions were 60 min, 713 K, 30 MPa, and EK treatment time, constant current density were 11 h, 20 mA cm -2 , respectively. The recovery percentages of copper and lead under optimum SCWO + EK treatment conditions were around 84.2% and 89.4%, respectively. In the optimized EK treatment, 74% of Cu was recovered as a deposit on the cathode with a purity of 97.6%, while Pb was recovered as concentrated solutions in either anode (23.1%) or cathode (66.3%) compartments but little was deposited on the electrodes. It is believed that the process is effective and practical for Cu and Pb recovery from waste electric and electronic equipments.

Scale-up on electrokinetic remediation: Engineering and technological parameters

Energy Technology Data Exchange (ETDEWEB)

López-Vizcaíno, Rubén [Department of Chemical Engineering, Institute of Chemical & Environmental Technologies, University of Castilla-La Mancha, Campus Universitario s/n, 13071 Ciudad Real (Spain); Navarro, Vicente; León, María J. [Geoenvironmental Group, Civil Engineering School, University of Castilla-La Mancha, Avda. Camilo José Cela s/n, 13071 Ciudad Real (Spain); Risco, Carolina [Department of Chemical Engineering, Institute of Chemical & Environmental Technologies, University of Castilla-La Mancha, Campus Universitario s/n, 13071 Ciudad Real (Spain); Rodrigo, Manuel A., E-mail: manuel.rodrigo@uclm.es [Department of Chemical Engineering, Faculty of Chemical Sciences & Technologies, University of Castilla-La Mancha, Campus Universitario s/n, 13071 Ciudad Real (Spain); Sáez, Cristina; Cañizares, Pablo [Department of Chemical Engineering, Faculty of Chemical Sciences & Technologies, University of Castilla-La Mancha, Campus Universitario s/n, 13071 Ciudad Real (Spain)

2016-09-05

Highlights: • Moisture and compaction of soil must be re-establish in Scale-up of EKR. • Degree of compaction of soil depends on moisture, type of soil and EKR reactor. • Scale of EKR process determines the energy consumption in the treatment. • Electroosmosis and electromigration processes are favoured in prototype scale. • In real scale EKR processes it is important determine evaporation and leaks effects. - Abstract: This study analyses the effect of the scale-up of electrokinetic remediation (EKR) processes in natural soils. A procedure is proposed to prepare soils based on a compacting process to obtaining soils with similar moisture content and density to those found in real soils in the field. The soil used here was from a region with a high agrarian activity (Mora, Spain). The scale-up study was performed in two installations at different scales: a mock-up pilot scale (0.175 m{sup 3}) and a prototype with a scale that was very similar to a real application (16 m{sup 3}). The electrode configuration selected consisted of rows of graphite electrodes facing each other located in electrolyte wells. The discharge of 20 mg of 2,4-dichlorophenoxyacetic acid [2,4-D] per kg of dry soil was treated by applying an electric potential gradient of 1 V cm{sup −1}. An increase in scale was observed to directly influence the amount of energy supplied to the soil being treated. As a result, electroosmotic and electromigration flows and electric heating are more intense than in smaller-scale tests (24%, 1% and 25%, respectively respect to the values in prototype). In addition, possible leaks were evaluated by conducting a watertightness test and quantifying evaporation losses.

Investigation of electrokinetic and electrorheological properties of polyindole prepared in the presence of a surfactant

Energy Technology Data Exchange (ETDEWEB)

Unal, H. Ibrahim, E-mail: hiunal@gazi.edu.tr [Gazi University, Chemistry Department, Smart Materials Research Lab., Ankara (Turkey); Sahan, Bekir; Erol, Ozlem [Gazi University, Chemistry Department, Smart Materials Research Lab., Ankara (Turkey)

2012-05-15

Highlights: Black-Right-Pointing-Pointer Aggregated morphology was determined for PIN, spherical and porous hollows and everniae form morphologies were recorded for SPIN. Black-Right-Pointing-Pointer The PIN/SO and SPIN/SO systems showed almost similar electrokinetic attitudes and a typical shear thinning non-Newtonian viscoelastic behavior, vibration damping capability at elevated frequencies, and enhanced storage moduli with increasing temperature. Black-Right-Pointing-Pointer Non-linear recoverable viscoelastic manner was revealed from the creep-recovery experiments under external electric field. - Abstract: In this study, synthesis of polyindole (PIN) was carried out without and with the presence of a sodium dodecyl sulfate (SDS) surfactant (SPIN), using FeCl{sub 3} as an oxidizing agent. The synthesized materials were subjected to various characterizations techniques namely: particle size, magnetic susceptibility, elemental analysis, density, conductivity, dielectric constant, FTIR, {sup 1}H NMR, TGA, XRD, and SEM. Characterization results revealed the successful preparation of the homopolymers of PIN and SPIN. Zeta ({zeta})-potentials of the samples were measured in aqueous and non-aqueous (silicone oil, SO) media. Electrokinetic properties of PIN and SPIN in aqueous media were determined by {zeta}-potential measurements in the presence of various electrolytes (NaCl, BaCl{sub 2}, AlCl{sub 3}, Na{sub 2}SO{sub 4}) and surfactants (cetyltrimethyl ammonium bromide, SDS, and Triton X-100). Besides, the effect of pH onto {zeta}-potentials of the materials was also examined. The suspensions prepared in SO were subjected to external electric field strength and their electrorheological (ER) properties were investigated. Then the effects of shear rate, frequency, and temperature onto ER activities of the suspensions were examined. Further, creep and creep-recovery tests were applied to the PIN/SO and SPIN/SO suspension systems and reversible non-linear viscoelastic

Electrokinetically driven continuous-flow enrichment of colloidal particles by Joule heating induced temperature gradient focusing in a convergent-divergent microfluidic structure.

Science.gov (United States)

Zhao, Cunlu; Ge, Zhengwei; Song, Yongxin; Yang, Chun

2017-09-07

Enrichment of colloidal particles in continuous flow has not only numerous applications but also poses a great challenge in controlling physical forces that are required for achieving particle enrichment. Here, we for the first time experimentally demonstrate the electrokinetically-driven continuous-flow enrichment of colloidal particles with Joule heating induced temperature gradient focusing (TGF) in a microfluidic convergent-divergent structure. We consider four mechanisms of particle transport, i.e., advection due to electroosmosis, electrophoresis, dielectrophoresis and, and further clarify their roles in the particle enrichment. It is experimentally determined and numerically verified that the particle thermophoresis plays dominant roles in enrichment of all particle sizes considered in this study and the combined effect of electroosmosis-induced advection and electrophoresis is mainly to transport particles to the zone of enrichment. Specifically, the enrichment of particles is achieved with combined DC and AC voltages rather than a sole DC or AC voltage. A numerical model is formulated with consideration of the abovementioned four mechanisms, and the model can rationalize the experimental observations. Particularly, our analysis of numerical and experimental results indicates that thermophoresis which is usually an overlooked mechanism of material transport is crucial for the successful electrokinetic enrichment of particles with Joule heating induced TGF.

Improving sensitivity of residual current transformers to high frequency earth fault currents

Directory of Open Access Journals (Sweden)

Czapp Stanislaw

2017-09-01

Full Text Available For protection against electric shock in low voltage systems residual current devices are commonly used. However, their proper operation can be interfered when high frequency earth fault current occurs. Serious hazard of electrocution exists then. In order to detect such a current, it is necessary to modify parameters of residual current devices, especially the operating point of their current transformer. The authors proposed the modification in the structure of residual current devices. This modification improves sensitivity of residual current devices when high frequency earth fault current occurs. The test of the modified residual current device proved that the authors’ proposition is appropriate.

High temperature superconductor current leads

International Nuclear Information System (INIS)

Zeimetz, B.; Liu, H.K.; Dou, S.X.

1996-01-01

Full text: The use of superconductors in high electrical current applications (magnets, transformers, generators etc.) usually requires cooling with liquid Helium, which is very expensive. The superconductor itself produces no heat, and the design of Helium dewars is very advanced. Therefore most of the heat loss, i.e. Helium consumption, comes from the current lead which connects the superconductor with its power source at room temperature. The current lead usually consists of a pair of thick copper wires. The discovery of the High Temperature Superconductors makes it possible to replace a part of the copper with superconducting material. This drastically reduces the heat losses because a) the superconductor generates no resistive heat and b) it is a very poor thermal conductor compared with the copper. In this work silver-sheathed superconducting tapes are used as current lead components. The work comprises both the production of the tapes and the overall design of the leads, in order to a) maximize the current capacity ('critical current') of the superconductor, b) minimize the thermal conductivity of the silver clad, and c) optimize the cooling conditions

Reducing AC-Winding Losses in High-Current High-Power Inductors

DEFF Research Database (Denmark)

Nymand, Morten; Madawala, Udaya K.; Andersen, Michael Andreas E.

2009-01-01

Foil windings are preferable in high-current high-power inductors to realize compact designs and to reduce dc-current losses. At high frequency, however, proximity effect will cause very significant increase in ac resistance in multi-layer windings, and lead to high ac winding losses. This paper ...

High current induction linacs

International Nuclear Information System (INIS)

Barletta, W.; Faltens, A.; Henestroza, E.; Lee, E.

1994-07-01

Induction linacs are among the most powerful accelerators in existence. They have accelerated electron bunches of several kiloamperes, and are being investigated as drivers for heavy ion driven inertial confinement fusion (HIF), which requires peak beam currents of kiloamperes and average beam powers of some tens of megawatts. The requirement for waste transmutation with an 800 MeV proton or deuteron beam with an average current of 50 mA and an average power of 40 MW lies midway between the electron machines and the heavy ion machines in overall difficulty. Much of the technology and understanding of beam physics carries over from the previous machines to the new requirements. The induction linac allows use of a very large beam aperture, which may turn out to be crucial to reducing beam loss and machine activation from the beam halo. The major issues addressed here are transport of high intensity beams, availability of sources, efficiency of acceleration, and the state of the needed technology for the waste treatment application. Because of the transformer-like action of an induction core and the accompanying magnetizing current, induction linacs make the most economic sense and have the highest efficiencies with large beam currents. Based on present understanding of beam transport limits, induction core magnetizing current requirements, and pulse modulators, the efficiencies could be very high. The study of beam transport at high intensities has been the major activity of the HIF community. Beam transport and sources are limiting at low energies but are not significant constraints at the higher energies. As will be shown, the proton beams will be space-charge-dominated, for which the emittance has only a minor effect on the overall beam diameter but does determine the density falloff at the beam edge

Micellar electrokinetic chromatographic determination of triazine herbicides in water samples.

Science.gov (United States)

Li, Zhi; Zhang, Shuaihua; Yin, Xiaofang; Wang, Chun; Wang, Zhi

2014-09-01

Dispersive liquid-liquid microextraction combined with online sweeping preconcentration in micellar electrokinetic chromatography was developed for the simultaneous determination of five triazine herbicides (atrazine, simazine, propazine, prometon and simetryn) in water samples. Several experimental parameters affecting the extraction efficiencies such as the type and volume of both the extraction and dispersive solvents, the addition of salt to sample solution, the extraction time and the pH of the sample solution were investigated. Under optimum conditions, the linearity of the method was good in the range from 0.33 to 20 ng mL(-1) for simazine, propazine, atrazine and simetryn, and from 0.17 to 20 ng mL(-1) for prometon, respectively. The sensitivity enrichment factors were in the range from 1750 to 2100, depending on the compound. The limit of detection (S/N = 3) ranged from 0.05 to 0.10 ng mL(-1). The developed method was successfully applied to the analysis of the five triazines in river, ground and well waters. © The Author [2013]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Properties of high current RFQ injectors

International Nuclear Information System (INIS)

Schempp, A.; Goethe, J.W.

1996-01-01

RFQ linacs are efficient, compact low energy ion structures, which have found numerous applications. They use electrical rf focusing and can capture, bunch and transmit high current ion beams. Some recent development and new projects like a heavy ion injectors for a cyclotron, and the status of the work on high current high duty factor RFQs will be discussed. (author)

Properties of high current RFQ injectors

Energy Technology Data Exchange (ETDEWEB)

Schempp, A.; Goethe, J.W. [Frankfurt Univ. (Germany). Inst. fuer Angewandte Physik

1996-12-31

RFQ linacs are efficient, compact low energy ion structures, which have found numerous applications. They use electrical rf focusing and can capture, bunch and transmit high current ion beams. Some recent development and new projects like a heavy ion injectors for a cyclotron, and the status of the work on high current high duty factor RFQs will be discussed. (author) 2 refs.

Electrokinetic remediation of contaminated soil from heavy metals and cobalt radioactive isotope

International Nuclear Information System (INIS)

Abdel Raouf, M.W.; Abdel Aziz, M.M.

2005-01-01

The present work presents a simple and inexpensive method for the in situ electrokinetic remediation of simulated contamined soil samples. Soil samples were collcted at inshas site (Egypt) at different depths 2-4, 4-6, and 6-8 m, purified from large and hard lumps, and characterized. To improve their hydraulic mobility, equal weights from the simulated soil and sand (0.5kg) were throughly mixed. The soil mixtures were dried under an infrared lamp, ground to a fine powder using a hand mortar. In this study, the soil samples were loaded separately by 250 ml CuSo 4 (1M) for Cu 2+ or CdCl 2 (1M) for Cd 2+ ,/or with simulated aqueous radioactive solution of 60 Co. Contaminated soil samples were left in contact with contaminant solutions for 48 hours in a closed container. Oven dried loaded soils samples were wasted five times by water to remove the free cations; then intial contaminant concentration of copper, calmium, and cobalt in soil samples was measured. To permit for the passage of electric current, loaded soil samples were wet with synthetic ground water (100 ml). A bench scale cell (13.0 cm x 6.0 cm x 6.5 cm) made from plexiglas was packed with 0.2 kg soil sample. A platinum sheet (4 cm x 0.5 cm x 0.05 cm) represented the anode; a graphite bar (iameter 0.5 cm and height 4 cm) represented the cathode, 6.0 cm apart from the anode. In the cell, the applied electric current and potential difference was kept constant at 60 mA and 10V, respectively for three hours treatment duration. The used electrodes were immersed into fired clay pottery bodies (net internal volume 15 ml) full with synthetic ground water. Percent of removal (P r ) of Cu 2+ , Cd 2+ , and 60 Co obtained after three hours waslarger than 97% at current density 2.2mA.cm -2 , and energy consumption 0.12 W.h.kg -1 . The advantages of the applied technique included the close control over the direction of movement of water and dissolved contsminants, retention of the contaminants within a confined zone

Moving charged particles in lattice Boltzmann-based electrokinetics

Science.gov (United States)

Kuron, Michael; Rempfer, Georg; Schornbaum, Florian; Bauer, Martin; Godenschwager, Christian; Holm, Christian; de Graaf, Joost

2016-12-01

The motion of ionic solutes and charged particles under the influence of an electric field and the ensuing hydrodynamic flow of the underlying solvent is ubiquitous in aqueous colloidal suspensions. The physics of such systems is described by a coupled set of differential equations, along with boundary conditions, collectively referred to as the electrokinetic equations. Capuani et al. [J. Chem. Phys. 121, 973 (2004)] introduced a lattice-based method for solving this system of equations, which builds upon the lattice Boltzmann algorithm for the simulation of hydrodynamic flow and exploits computational locality. However, thus far, a description of how to incorporate moving boundary conditions into the Capuani scheme has been lacking. Moving boundary conditions are needed to simulate multiple arbitrarily moving colloids. In this paper, we detail how to introduce such a particle coupling scheme, based on an analogue to the moving boundary method for the pure lattice Boltzmann solver. The key ingredients in our method are mass and charge conservation for the solute species and a partial-volume smoothing of the solute fluxes to minimize discretization artifacts. We demonstrate our algorithm's effectiveness by simulating the electrophoresis of charged spheres in an external field; for a single sphere we compare to the equivalent electro-osmotic (co-moving) problem. Our method's efficiency and ease of implementation should prove beneficial to future simulations of the dynamics in a wide range of complex nanoscopic and colloidal systems that were previously inaccessible to lattice-based continuum algorithms.

Interactions of structurally modified surfactants with reservoir minerals: Calorimetric, spectroscopic and electrokinetic study

Energy Technology Data Exchange (ETDEWEB)

Somasundaran, P.; Sivakumar, A.; Xu, Q.

1991-03-01

The objective of this project is to elucidate mechanisms of adsorption of structurally modified surfactants on reservoir minerals and to develop a full understanding of the effect of the surfactant structure on the nature of the adsorbed layers at the molecular level. An additional aim is to study the adsorption of surfactant mixtures on simple well-characterized minerals and on complex minerals representing real conditions. The practical goal of these studies is the identification of the optimum surfactant structures and their combinations for micellar flooding. In this work, the experiments on adsorption were focussed on the position of sulfonate and methyl groups on the aromatic ring of alkyl xylene sulfonates. A multi-pronged approach consisting of calorimetry, electrokinetics, wettability and spectroscopy is planned to elucidate the adsorption mechanism of surfactants and their mixtures on minerals such as alumina and kaolinite. 32 refs., 15 figs., 7 tabs.

Stacking-cyclodextrin-microchip electrokinetic chromatographic determination of gabapentinoid drugs in pharmaceutical and biological matrices.

Science.gov (United States)

Zeid, Abdallah M; Kaji, Noritada; Nasr, Jenny Jeehan M; Belal, Fathalla F; Baba, Yoshinobu; Walash, Mohamed I

2017-06-23

A facile, rapid, and highly sensitive microchip-based electrokinetic chromatographic method was developed for the simultaneous analysis of two gabapentinoid drugs, gabapentin (GPN) and pregabalin (PGN). Both drugs were first reacted with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) via nucleophilic substitution reactions to yield highly fluorescent products with λ ex/em 470/540nm. Analyses of both fluorescently labeled compounds were achieved within 200s in a poly(methyl methacrylate) (PMMA) microchip with a 30mm separation channel. Optimum separation was achieved using a borate buffer (pH 9.0) solution containing methylcellulose and β-cyclodextrin (β-CD) as buffer additives. Methylcellulose acted as a dynamic coating to prevent adsorption of the studied compounds on the inner surfaces of the microchannels, while β-CD acted as a pseudo-stationary phase to improve the separation efficiency between the labeled drugs with high resolution (Rs>7). The fluorescence intensities of the labeled drugs were measured using a light emitting diode-induced fluorescence detector at 540nm after excitation at 470nm. The sensitivity of the method was enhanced 14- and 17-fold for PGN and GPN, respectively by field-amplified stacking relative to traditional pinched injection so that it could quantify 10ngmL -1 for both analytes, with a detection limit lower than 3ngmL -1 . The developed method was efficiently applied to analyze PGN and GPN in their pharmaceutical dosage forms and in biological fluids. The extraction recoveries of the studied drugs from plasma and urine samples were more than 89% with%RSD values lower than 6.2. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of water chemistry on corrosion of stainless steel and deposition of corrosion products in high temperature pressurised water

International Nuclear Information System (INIS)

Morrison, Jonathan; Cooper, Christopher; Ponton, Clive; Connolly, Brian; Banks, Andrew

2012-09-01

temperatures between 200 and 300 deg. C. Finally, it has been recognised that there is an electrokinetic component to the deposition occurring within flow restrictions, but very few investigations have been performed to study the electrokinetic behaviour at a geometric flow restriction. Work that has been previously attempted has focused on electrokinetics of crud deposition in the secondary side water chemistry. This electrokinetic behaviour, manifested as a streaming current, is believed to be influential in the electrochemical reactions occurring at flow restrictions resulting in the formation of the observed crud deposits. As part of this programme a high velocity (up to 30 ms -1 ) flow rate loop operating at high temperature (up to 315 deg. C) and pressure (up to 150 bar) has been constructed to study the deposition of material at a flow restriction of known geometry under simulated primary side water chemistry, temperature and pressure conditions. Furthermore, to assist in the understanding of measured streaming currents present as a function of desired geometries, preliminary experiments utilising a second 'cold' loop will be performed, where water of up to 373 K will be flowed at high velocity through an instrumented sample section. (authors)

BioCrack {sup registered}. Enhanced gas yield by electrokinetic disintegration; BioCrack {sup registered}. Steigerung der Gasausbeute durch elektrokinetische Desintegration

Energy Technology Data Exchange (ETDEWEB)

Liebich, Markus [Hugo Vogelsang Maschinenbau GmbH (Germany)

2011-07-01

In the electrokinetic disintegration process, the fluid flows through a pipeline system to which a HV field is applied. The electric forces of the HV field deform and destabilise the cell membrane. Once the deformation exceeds the elastic resistance of the cell membrane, the cell membrane will become permeable, and the cell content will be released and can be used for gas production. The advantages of theprocess are the low investment cost, simple retrofitting, high availability, and low energy cost (35 W per module). [German] Bei der elektrokinetischen Desintegration durchfliesst das Medium ein Rohrleitungssystem in dem ein Hochspannungsfeld anliegt. Durch die auftretenden elektrischen Kraefte im Hochspannungsfeld wird die Zellmembran verformt und destabilisiert. Uebersteigt die Verformung die elastische Widerstandkraft der Zellmembran, so wird diese durchlaessig. Dadurch werden die Zellinhaltsstoffe freigesetzt und koennen zur Gaserzeugung genutzt werden. Die Vorteile dieses Verfahrens liegen in den geringen Investitionskosten gegenueber anderen Desintegrationsverfahren, der einfachen Nachruestbarkeit, der hoher Anlagenverfuegbarkeit sowie in den geringen Energiekosten (35 W pro Modul).

Capillaries modified by noncovalent anionic polymer adsorption for capillary zone electrophoresis, micellar electrokinetic capillary chromatography and capillary electrophoresis mass spectrometry

DEFF Research Database (Denmark)

Bendahl, L; Hansen, S H; Gammelgaard, Bente

2001-01-01

A simple coating procedure for generation of a high and pH-independent electroosmotic flow in capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography (MEKC) is described. The bilayer coating was formed by noncovalent adsorption of the ionic polymers Polybrene...... capillaries was (4.9+/-0.1) x 10(-4) cm2V(-1)s(-1) in a pH-range of 2-10 (ionic strength = 30 mM). When alkaline compounds were used as test substances intracapillary and intercapillary migration time variations (n = 6) were less than 1% relative standard deviation (RSD) and 2% RSD, respectively in the entire...... pH range. The coating was fairly stable in the presence of sodium dodecyl sulfate, and this made it possible to perform fast MEKC separations at low pH. When neutral compounds were used as test substances, the intracapillary migration time variations (n = 6) were less than 2% RSD in a pH range of 2...

THEORETICAL AND EXPERIMENTAL MODELING OF MULTI-SPECIES TRANSPORT IN SOILS UNDER ELECTRIC FIELDS

Science.gov (United States)

Electrokinetics employs the use of electrodes implanted in soils-contaminated media. Electrodes are supplied with direct current (dc) facilitating ionic transport and subsequent removal. This project investigates the feasibility and efficiency of electrokinetic transport of lea...

Shell structure of natural rubber particles: evidence of chemical stratification by electrokinetics and cryo-TEM.

Science.gov (United States)

Rochette, Christophe N; Crassous, Jérôme J; Drechsler, Markus; Gaboriaud, Fabien; Eloy, Marie; de Gaudemaris, Benoît; Duval, Jérôme F L

2013-11-26

The interfacial structure of natural rubber (NR) colloids is investigated by means of cryogenic transmission electron microscopy (cryo-TEM) and electrokinetics over a broad range of KNO3 electrolyte concentrations (4-300 mM) and pH values (1-8). The asymptotic plateau value reached by NR electrophoretic mobility (μ) in the thin double layer limit supports the presence of a soft (ion- and water-permeable) polyelectrolytic type of layer located at the periphery of the NR particles. This property is confirmed by the analysis of the electron density profile obtained from cryo-TEM that evidences a ∼2-4 nm thick corona surrounding the NR polyisoprene core. The dependence of μ on pH and salt concentration is further marked by a dramatic decrease of the point of zero electrophoretic mobility (PZM) from 3.6 to 0.8 with increasing electrolyte concentration in the range 4-300 mM. Using a recent theory for electrohydrodynamics of soft multilayered particles, this "anomalous" dependence of the PZM on electrolyte concentration is shown to be consistent with a radial organization of anionic and cationic groups across the peripheral NR structure. The NR electrokinetic response in the pH range 1-8 is indeed found to be equivalent to that of particles surrounded by a positively charged ∼3.5 nm thick layer (mean dissociation pK ∼ 4.2) supporting a thin and negatively charged outermost layer (0.6 nm in thickness, pK ∼ 0.7). Altogether, the strong dependence of the PZM on electrolyte concentration suggests that the electrostatic properties of the outer peripheral region of the NR shell are mediated by lipidic residues protruding from a shell containing a significant amount of protein-like charges. This proposed NR shell interfacial structure questions previously reported NR representations according to which the shell consists of either a fully mixed lipid-protein layer, or a layer of phospholipids residing exclusively beneath an outer proteic film.

High current polarized electron source

Science.gov (United States)

Suleiman, R.; Adderley, P.; Grames, J.; Hansknecht, J.; Poelker, M.; Stutzman, M.

2018-05-01

Jefferson Lab operates two DC high voltage GaAs photoguns with compact inverted insulators. One photogun provides the polarized electron beam at the Continuous Electron Beam Accelerator Facility (CEBAF) up to 200 µA. The other gun is used for high average current photocathode lifetime studies at a dedicated test facility up to 4 mA of polarized beam and 10 mA of un-polarized beam. GaAs-based photoguns used at accelerators with extensive user programs must exhibit long photocathode operating lifetime. Achieving this goal represents a significant challenge for proposed facilities that must operate in excess of tens of mA of polarized average current. This contribution describes techniques to maintain good vacuum while delivering high beam currents, and techniques that minimize damage due to ion bombardment, the dominant mechanism that reduces photocathode yield. Advantages of higher DC voltage include reduced space-charge emittance growth and the potential for better photocathode lifetime. Highlights of R&D to improve the performance of polarized electron sources and prolong the lifetime of strained-superlattice GaAs are presented.

Electrokinetic gated injection-based microfluidic system for quantitative analysis of hydrogen peroxide in individual HepG2 cells.

Science.gov (United States)

Zhang, Xinyuan; Li, Qingling; Chen, Zhenzhen; Li, Hongmin; Xu, Kehua; Zhang, Lisheng; Tang, Bo

2011-03-21

A microfluidic system to determine hydrogen peroxide (H(2)O(2)) in individual HepG2 cells based on the electrokinetic gated injection was developed for the first time. A home-synthesized fluorescent probe, bis(p-methylbenzenesulfonate)dichlorofluorescein (FS), was employed to label intracellular H(2)O(2) in the intact cells. On a simple cross microchip, multiple single-cell operations, including single cell injection, cytolysis, electrophoresis separation and detection of H(2)O(2), were automatically carried out within 60 s using the electrokinetic gated injection and laser-induced fluorescence detection (LIFD). The performance of the method was evaluated under the optimal conditions. The linear calibration curve was over a range of 4.39-610 amol (R(2)=0.9994). The detection limit was 0.55 amol or 9.0×10(-10) M (S/N=3). The relative standard deviations (RSDs, n=6) of migration time and peak area were 1.4% and 4.8%, respectively. With the use of this method, the average content of H(2)O(2) in single HepG2 cells was found to be 16.09±9.84 amol (n=15). Separation efficiencies in excess of 17,000 theoretical plates for the cells were achieved. These results demonstrated that the efficient integration and automation of these single-cell operations enabled the sensitive, reproducible, and quantitative examination of intracellular H(2)O(2) at single-cell level. Owing to the advantages of simple microchip structure, controllable single-cell manipulation and ease in building, this platform provides a universal way to automatically determine other intracellular constituents within single cells. This journal is © The Royal Society of Chemistry 2011

Electrokinetic-Fenton remediation of organochlorine pesticides from historically polluted soil.

Science.gov (United States)

Ni, Maofei; Tian, Shulei; Huang, Qifei; Yang, Yanmei

2018-04-01

Soil contamination by persistent organic pollutants (POPs) poses a great threat to historically polluted soil worldwide. In this study, soils were characterized, and organochlorine pesticides contained in the soils were identified and quantified. Individual electrokinetic (IE), EK-Fenton-coupled technologies (EF), and enhanced EK-Fenton treatment (E-1, E-2, and E-3) were applied to remediate soils contaminated with hexachloro-cyclohexane soprocide (HCH) and dichloro-diphenyl-trichloroethane (DDT). Variation of pH, electrical conductivity, and electroosmotic flow was evaluated during the EK-Fenton process. The IE treatment showed low removal efficiency for HCHs (30.5%) and DDTs (25.9%). In the EF treatment, the highest removal level (60.9%) was obtained for α-HCH, whereas P,P-DDT was the lowest (40.0%). Low solubility of pollutants impeded the HCH and DDT removal. After enhanced EK-Fenton treatment, final removal of pollutants decreased as follows: β-HCH (82.6%) > γ-HCH (81.6%) > α-HCH (81.2%) > δ-HCH (80.0%) > P,P-DDD (73.8%) > P,P-DDE (73.1%) > P,P-DDT (72.6%) > O,P-DDT (71.5%). The results demonstrate that EK-Fenton is a promising technology for POP removal in historically polluted soil.

Electrokinetic migration across artificial liquid membranes Tuning the membrane chemistry to different types of drug substances.

Science.gov (United States)

Gjelstad, Astrid; Rasmussen, Knut Einar; Pedersen-Bjergaard, Stig

2006-08-18

Twenty different basic drugs were electrokinetically extracted across a thin artificial organic liquid membrane with a 300 V d.c. electrical potential difference as the driving force. From a 300 microl aqueous sample (acidified corresponding to 10mM HCl), the drugs were extracted for 5 min through a 200 microm artificial liquid membrane of a water immiscible organic solvent immobilized in the pores of a polypropylene hollow fiber, and into a 30 microl aqueous acceptor solution of 10mM HCl inside the lumen of the hollow fiber. Hydrophobic basic drugs (logP>1.7) were effectively isolated utilizing 2-nitrophenyl octyl ether (NPOE) as the artificial liquid membrane, with recoveries up to 83%. For more hydrophilic basic drugs (logPpermeation of the interface.

Review of chemical and electrokinetic remediation of PCBs contaminated soils and sediments.

Science.gov (United States)

Fan, Guangping; Wang, Yu; Fang, Guodong; Zhu, Xiangdong; Zhou, Dongmei

2016-09-14

Polychlorinated biphenyls (PCBs) are manmade organic compounds, and pollution due to PCBs has been a global environmental problem because of their persistence, long-range atmospheric transport and bioaccumulation. Many physical, chemical and biological technologies have been utilized to remediate PCBs contaminated soils and sediments, and there are some emerging new technologies and combined methods that may provide cost-effective alternatives to the existing remediation practice. This review provides a general overview on the recent developments in chemical treatment and electrokinetic remediation (EK) technologies related to PCBs remediation. In particular, four technologies including photocatalytic degradation of PCBs combined with soil washing, Fe-based reductive dechlorination, advanced oxidation process, and EK/integrated EK technology (e.g., EK coupled with chemical oxidation, nanotechnology and bioremediation) are reviewed in detail. We focus on the fundamental principles and governing factors of chemical technologies, and EK/integrated EK technologies. Comparative analysis of these technologies including their major advantages and disadvantages is summarized. The existing problems and future prospects of these technologies regarding PCBs remediation are further highlighted.

Electrokinetic Analysis of Energy Harvest from Natural Salt Gradients in Nanochannels.

Science.gov (United States)

He, Yuhui; Huang, Zhuo; Chen, Bowei; Tsutsui, Makusu; Shui Miao, Xiang; Taniguchi, Masateru

2017-10-13

The Gibbs free energy released during the mixing of river and sea water has been illustrated as a promising source of clean and renewable energy. Reverse electrodialysis (RED) is one major strategy to gain electrical power from this natural salinity, and recently by utilizing nanochannels a novel mode of this approach has shown improved power density and energy converting efficiency. In this work, we carry out an electrokinetic analysis of the work extracted from RED in the nanochannels. First, we outline the exclusion potential effect induced by the inhomogeneous distribution of extra-counterions along the channel axis. This effect is unique in nanochannel RED and how to optimize it for energy harvesting is the central topic of this work. We then discuss two important indexes of performance, which are the output power density and the energy converting efficiency, and their dependence on the nanochannel parameters such as channel material and geometry. In order to yield maximized output electrical power, we propose a device design by stepwise usage of the saline bias, and the lengths of the nanochannels are optimized to achieve the best trade-off between the input thermal power and the energy converting efficiency.

Direct numerical simulation of electrokinetic instability and transition to chaotic motion

Science.gov (United States)

Demekhin, E. A.; Nikitin, N. V.; Shelistov, V. S.

2013-12-01

A new type of instability—electrokinetic instability—and an unusual transition to chaotic motion near a charge-selective surface (semiselective electric membrane, electrode, or system of micro-/nanochannels) was studied by the numerical integration of the Nernst-Planck-Poisson-Stokes system and a weakly nonlinear analysis near the threshold of instability. A special finite-difference method was used for the space discretization along with a semi-implicit 31/3-step Runge-Kutta scheme for the integration in time. Two kinds of initial conditions were considered: (a) white-noise initial conditions to mimic "room disturbances" and subsequent natural evolution of the solution, and (b) an artificial monochromatic ion distribution with a fixed wave number to simulate regular wave patterns. The results were studied from the viewpoint of hydrodynamic stability and bifurcation theory. The threshold of electroconvective movement was found by the linear spectral stability theory, the results of which were confirmed by numerical simulation of the entire system. Our weakly nonlinear analysis and numerical integration of the entire system predict possibility of both kinds of bifurcations at the critical point, supercritical and subcritical, depending on the system parameters. The following regimes, which replace each other as the potential drop between the selective surfaces increases, were obtained: one-dimensional steady solution, two-dimensional steady electroconvective vortices (stationary point in a proper phase space), unsteady vortices aperiodically changing their parameters (homoclinic contour), periodic motion (limit cycle), and chaotic motion. The transition to chaotic motion does not include Hopf bifurcation. The numerical resolution of the thin concentration polarization layer showed spike-like charge profiles along the surface, which could be, depending on the regime, either steady or aperiodically coalescent. The numerical investigation confirmed the

Direct numerical simulation of electrokinetic instability and transition to chaotic motion

International Nuclear Information System (INIS)

Demekhin, E. A.; Nikitin, N. V.; Shelistov, V. S.

2013-01-01

A new type of instability—electrokinetic instability—and an unusual transition to chaotic motion near a charge-selective surface (semiselective electric membrane, electrode, or system of micro-/nanochannels) was studied by the numerical integration of the Nernst-Planck-Poisson-Stokes system and a weakly nonlinear analysis near the threshold of instability. A special finite-difference method was used for the space discretization along with a semi-implicit 31/3 -step Runge-Kutta scheme for the integration in time. Two kinds of initial conditions were considered: (a) white-noise initial conditions to mimic “room disturbances” and subsequent natural evolution of the solution, and (b) an artificial monochromatic ion distribution with a fixed wave number to simulate regular wave patterns. The results were studied from the viewpoint of hydrodynamic stability and bifurcation theory. The threshold of electroconvective movement was found by the linear spectral stability theory, the results of which were confirmed by numerical simulation of the entire system. Our weakly nonlinear analysis and numerical integration of the entire system predict possibility of both kinds of bifurcations at the critical point, supercritical and subcritical, depending on the system parameters. The following regimes, which replace each other as the potential drop between the selective surfaces increases, were obtained: one-dimensional steady solution, two-dimensional steady electroconvective vortices (stationary point in a proper phase space), unsteady vortices aperiodically changing their parameters (homoclinic contour), periodic motion (limit cycle), and chaotic motion. The transition to chaotic motion does not include Hopf bifurcation. The numerical resolution of the thin concentration polarization layer showed spike-like charge profiles along the surface, which could be, depending on the regime, either steady or aperiodically coalescent. The numerical investigation confirmed the

Direct numerical simulation of electrokinetic instability and transition to chaotic motion

Energy Technology Data Exchange (ETDEWEB)

Demekhin, E. A., E-mail: edemekhi@gmail.com [Laboratory of Micro- and Nanofluidics, Moscow State University, Moscow 119192 (Russian Federation); Department of Computation Mathematics and Computer Science, Kuban State University, Krasnodar 350040 (Russian Federation); Institute of Mechanics, Moscow State University, Moscow 117192 (Russian Federation); Nikitin, N. V. [Institute of Mechanics, Moscow State University, Moscow 117192 (Russian Federation); Shelistov, V. S. [Institute of Mechanics, Moscow State University, Moscow 117192 (Russian Federation); Scientific Research Department, Kuban State University, Krasnodar 350040 (Russian Federation)

2013-12-15

A new type of instability—electrokinetic instability—and an unusual transition to chaotic motion near a charge-selective surface (semiselective electric membrane, electrode, or system of micro-/nanochannels) was studied by the numerical integration of the Nernst-Planck-Poisson-Stokes system and a weakly nonlinear analysis near the threshold of instability. A special finite-difference method was used for the space discretization along with a semi-implicit 31/3 -step Runge-Kutta scheme for the integration in time. Two kinds of initial conditions were considered: (a) white-noise initial conditions to mimic “room disturbances” and subsequent natural evolution of the solution, and (b) an artificial monochromatic ion distribution with a fixed wave number to simulate regular wave patterns. The results were studied from the viewpoint of hydrodynamic stability and bifurcation theory. The threshold of electroconvective movement was found by the linear spectral stability theory, the results of which were confirmed by numerical simulation of the entire system. Our weakly nonlinear analysis and numerical integration of the entire system predict possibility of both kinds of bifurcations at the critical point, supercritical and subcritical, depending on the system parameters. The following regimes, which replace each other as the potential drop between the selective surfaces increases, were obtained: one-dimensional steady solution, two-dimensional steady electroconvective vortices (stationary point in a proper phase space), unsteady vortices aperiodically changing their parameters (homoclinic contour), periodic motion (limit cycle), and chaotic motion. The transition to chaotic motion does not include Hopf bifurcation. The numerical resolution of the thin concentration polarization layer showed spike-like charge profiles along the surface, which could be, depending on the regime, either steady or aperiodically coalescent. The numerical investigation confirmed the

High current and high power superconducting rectifiers

International Nuclear Information System (INIS)

Kate, H.H.J. ten; Bunk, P.B.; Klundert, L.J.M. van de; Britton, R.B.

1981-01-01

Results on three experimental superconducting rectifiers are reported. Two of them are 1 kA low frequency flux pumps, one thermally and magnetically switched. The third is a low-current high-frequency magnetically switched rectifier which can use the mains directly. (author)

Dispersion and absorption of longitudinal electro-kinetic wave in ion-implanted GaN semiconductor plasmas

Energy Technology Data Exchange (ETDEWEB)

Soni, Dilip [Government P G Madhav Science College, Ujjain (M P) (India); Sharma, Giriraj, E-mail: grsharma@gmail.com [SRJ Government Girls’ College, Neemuch (M P) (India); Saxena, Ajay [Government College, Garoth, Dist. Mandsaur (M P) (India); Jadhav, Akhilesh [Government J Yoganandam Chhattisgarh College, Raipur (C G) (India)

2015-07-31

An analytical study on propagation characteristics of longitudinal electro-kinetic (LEK) waves is presented. Based on multi-fluid model of plasma, we have derived a dispersion relation for LEK waves in colloid laden GaN semiconductor plasmas. It is assumed that ions are implanted to form colloids in the GaN sample. The colloids are continuously bombarded by the plasma particles and stick on them, but they acquire a net negative charge due to relatively higher mobility of electrons. It is found from the dispersion relation that the presence of charged colloids not only modifies the existing modes but also supports new novel modes of LEKWs. It is hoped that the study would enhance understanding on dispersion and absorption of LEKWs and help in singling out the appropriate configurations in which GaN crystal would be better suited for fabrication of microwave devices.

Feasibility Of Coupling Permeable Bio-Barriers And Electrokinetics For The Treatment Of Diesel Hydrocarbons Polluted Soils

International Nuclear Information System (INIS)

Ramírez, Esperanza Mena; Jiménez, Cristina Sáez; Camacho, José Villaseñor; Rodrigo, Manuel A.Rodrigo; Cañizares, Pablo

2015-01-01

Highlights: • Electrokinetics and a biobarrier were combined to remediate of a diesel polluted soil. • pH gradients did not affect the biobarrier activity located in soil central position. • Microorganisms were partially detached from the biobarrier and moved across the soil. • An anionic surfactant helped the contact between pollutant and microorganisms. • A 39% of the diesel biodegradable fraction was homogeneously removed across the soil. - Abstract: In this study, the remediation of a diesel hydrocarbon-polluted clay soil using an electrochemical-biological combined technology is assessed. The polluted soil was subjected to an electrokinetic (EK) treatment with a biological permeable reactive barrier. A lab-scale electrochemical cell for soil treatment was used. The biological barrier placed in the soil was a biofilm reactor previously adapted for diesel degradation. A batch experiment of 336 h was conducted in a synthetic clay soil spiked with 10 g·kg −1 of diesel and a constant voltage gradient of 1.0 V cm −1 . Sodium dodecyl sulphate was used as an anionic surfactant in the cathodic well to allow for hydrocarbon emulsification during the treatment. At the end of the experiment, extreme pH values were observed near the electrodes. However, the pH remained constant at approximately 7.7 in the central biobarrier zone, which allowed for biological processes. Biological growth was observed in the biobarrier, and a part of the biofilm was detached and transported through the soil in both directions. Furthermore, the surfactant was transported across the soil due to electromigration and electroosmosis, which resulted in diesel emulsification. The combination of biological and EK phenomena finally resulted in a homogenous hydrocarbon removal of approximately 27% in the polluted soil, which indicated a 39% removal of the diesel biodegradable fraction. Due to the electroosmotic flow and the biological degradation, some of the water, surfactant and

A high-current, high-voltage power supply with special output current waveform for APS injector synchrotron dipole magnets

International Nuclear Information System (INIS)

Fathizadeh, M.; Despe, O.D.; McGhee, D.G.; Mills, F.E.; Turner, L.R.

1991-01-01

This paper describes a high-voltage, high-current power supply for the injector synchrotron dipole magnets at APS. In order to reset the dipole magnets in each cycle two different current waveforms are suggested. The first current waveform consists of three sections, namely: dc-reset, linear ramp, and recovery sections where injection is done ''on the fly''. The second current waveform consists of six different sections, dc-reset, transition to injection level, injection flat level, parabolic, linear ramp and recovery sections. The effect of such waveforms on the beam is discussed and the power supply limitations to follow such waveforms are given. The power supply limitations are due to the power components and control loops. The reference for the current loop is generated by a DAC which is discussed

Electrokinetic transport of rigid macroions in the thin double layer limit: a boundary element approach.

Science.gov (United States)

Allison, Stuart A; Xin, Yao

2005-08-15

A boundary element (BE) procedure is developed to numerically calculate the electrophoretic mobility of highly charged, rigid model macroions in the thin double layer regime based on the continuum primitive model. The procedure is based on that of O'Brien (R.W. O'Brien, J. Colloid Interface Sci. 92 (1983) 204). The advantage of the present procedure over existing BE methodologies that are applicable to rigid model macroions in general (S. Allison, Macromolecules 29 (1996) 7391) is that computationally time consuming integrations over a large number of volume elements that surround the model particle are completely avoided. The procedure is tested by comparing the mobilities derived from it with independent theory of the mobility of spheres of radius a in a salt solution with Debye-Huckel screening parameter, kappa. The procedure is shown to yield accurate mobilities provided (kappa)a exceeds approximately 50. The methodology is most relevant to model macroions of mean linear dimension, L, with 1000>(kappa)L>100 and reduced absolute zeta potential (q|zeta|/k(B)T) greater than 1.0. The procedure is then applied to the compact form of high molecular weight, duplex DNA that is formed in the presence of the trivalent counterion, spermidine, under low salt conditions. For T4 DNA (166,000 base pairs), the compact form is modeled as a sphere (diameter=600 nm) and as a toroid (largest linear dimension=600 nm). In order to reconcile experimental and model mobilities, approximately 95% of the DNA phosphates must be neutralized by bound counterions. This interpretation, based on electrokinetics, is consistent with independent studies.

High Critical Current Coated Conductors

Energy Technology Data Exchange (ETDEWEB)

Paranthaman, M. P.; Selvamanickam, V. (SuperPower, Inc.)

2011-12-27

One of the important critical needs that came out of the DOE’s coated conductor workshop was to develop a high throughput and economic deposition process for YBCO. Metal-organic chemical vapor deposition (MOCVD) technique, the most critical steps in high technical micro fabrications, has been widely employed in semiconductor industry for various thin film growth. SuperPower has demonstrated that (Y,Gd)BCO films can be deposited rapid with world record performance. In addition to high critical current density with increased film thickness, flux pinning properties of REBCO films needs to be improved to meet the DOE requirements for various electric-power equipments. We have shown that doping with Zr can result in BZO nanocolumns, but at substantially reduced deposition rate. The primary purpose of this subtask is to develop high current density MOCVD-REBCO coated conductors based on the ion-beam assisted (IBAD)-MgO deposition process. Another purpose of this subtask is to investigate HTS conductor design optimization (maximize Je) with emphasis on stability and protection issues, and ac loss for REBCO coated conductors.

Can neutral analytes be concentrated by transient isotachophoresis in micellar electrokinetic chromatography and how much?

Science.gov (United States)

Matczuk, Magdalena; Foteeva, Lidia S; Jarosz, Maciej; Galanski, Markus; Keppler, Bernhard K; Hirokawa, Takeshi; Timerbaev, Andrei R

2014-06-06

Transient isotachophoresis (tITP) is a versatile sample preconcentration technique that uses ITP to focus electrically charged analytes at the initial stage of CE analysis. However, according to the ruling principle of tITP, uncharged analytes are beyond its capacity while being separated and detected by micellar electrokinetic chromatography (MEKC). On the other hand, when these are charged micelles that undergo the tITP focusing, one can anticipate the concentration effect, resulting from the formation of transient micellar stack at moving sample/background electrolyte (BGE) boundary, which increasingly accumulates the analytes. This work expands the enrichment potential of tITP for MEKC by demonstrating the quantitative analysis of uncharged metal-based drugs from highly saline samples and introducing to the BGE solution anionic surfactants and buffer (terminating) co-ions of different mobility and concentration to optimize performance. Metallodrugs of assorted lipophilicity were chosen so as to explore whether their varying affinity toward micelles plays the role. In addition to altering the sample and BGE composition, optimization of the detection capability was achieved due to fine-tuning operational variables such as sample volume, separation voltage and pressure, etc. The results of optimization trials shed light on the mechanism of micellar tITP and render effective determination of selected drugs in human urine, with practical limits of detection using conventional UV detector. Copyright © 2014 Elsevier B.V. All rights reserved.

A new high performance current transducer

International Nuclear Information System (INIS)

Tang Lijun; Lu Songlin; Li Deming

2003-01-01

A DC-100 kHz current transducer is developed using a new technique on zero-flux detecting principle. It was shown that the new current transducer is of high performance, its magnetic core need not be selected very stringently, and it is easy to manufacture

Quench properties of high current superconductors

Energy Technology Data Exchange (ETDEWEB)

Garber, M; Sampson, W B

1980-01-01

A technique has been developed which allows the simultaneous determination of most of the important parameters of a high current superconductor. The critical current, propagation velocity, normal state resistivity, magnetoresistance, and enthalpy are determined as a function of current and applied field. The measurements are made on non-inductive samples which simulate conditions in full scale magnets. For wide, braided conductors the propagation velocity was found to vary approximately quadratically with current in the 2 to 5 kA region. A number of conductors have been tested including some Nb/sub 3/Sn braids which have critical currents in excess of 10 kA at 5 T, 4.2 K.

High-current beam transport in electrostatic accelerator tubes

International Nuclear Information System (INIS)

Ramian, G.; Elais, L.

1987-01-01

The UCSB Free Electron Laser (FEL) has successfully demonstrated the use of a commercial 6 megavolt electrostatic accelerator as a high current beam source in a recirculating configuration. The accelerator, manufactured by National Electrostatics Corp. (NEC), Middleton WI, uses two standard high gradient accelerator tubes. Suppression of ion multiplication was accomplished by NEC with apertures and a shaped electrostatic field. This field shaping has fortuitously provided a periodically reversing radial field component with sufficient focusing strength to transport electron beams of up to 3 Amps current. Present two-stage FEL work requires a 20 Amp beam and proposed very high voltage FEL designs require currents as high as 100 Amps. A plan to permit transport of such high current beams by the addition of solenoidal focussing elements is described

Cascade of kinetic energy and scalar variance in DC electrokinetic turbulence

Science.gov (United States)

Zhao, Wei; Wang, Guiren

2017-11-01

Turbulent flow can be generated by DC electrokinetic (EK) force based on the electric conductivity and permittivity variations in fluids, as have been demonstrated by Varshney et al (2016), where a -1.4 slope of velocity power spectrum is observed. Here, we theoretically found the scaling exponents of velocity and scalar structures in the electric-body-force (EBF) dominant subregion of DC EK turbulence were 2/5 (equivalent to the -7/5 slope of velocity power spectrum) and 4/5 respectively. The theory perfectly explains the experimental results of Varshney et al. (2016). Based on Kármán-Howarth equation with forcing terms, the energy cascade process of DC EK turbulence was also investigated. Depending on the electric Rayleigh number (Rae) , two different energy cascade processes may happen. When Rae is small, the kinetic energy cascades along inertial subregion and EBF dominant subregion in sequence, before it is dissipated by fluid viscosity. When Rae is sufficiently large, the inertial subregion may be absent with EBF dominant subregion left. This investigation is very important on understand EK turbulence, which could be widely existed in nature and applied in engineerings. The work was supported by NSFC (11672229), and NSF (CAREER CBET-0954977 and MRI CBET-1040227).

Propagation of electro-kinetic waves in magnetized GaN semiconductor with nano-sized ion colloids

Energy Technology Data Exchange (ETDEWEB)

Saxena, Ajay [Government College, Garoth, Dist. Mandsaur (M P) (India); Sharma, Giriraj, E-mail: grsharma@gmail.com [SRJ Government Girls’ College, Neemuch (M P) (India); Jat, K. L. [Swami Vivekanand Government P G College, Neemuch (M P) (India); Rishi, M. P. [Shahid Bhagat Singh Government P G College, Jaora, Dist Ratlam (M P) (India)

2015-07-31

Based on hydrodynamic model of multi-component plasma, an analytical study on propagation of longitudinal electro-kinetic (LEK) waves in wurtzite and zincblende structures of GaN is carried out. Nano-sized ion colloids (NICs) are embedded in the sample by the technique of ion-implantation. The implanted NICs are considered massive by an order as compared to the host lattice points and do not participate in Based LEK perturbations. Though, the NICs are continuously bombarded by the electrons as well as the holes yet, the former acquires a net negative charge owing to relatively higher mobility of electrons and consequently results into depletion of electron density in the medium. It i s found that the presence of charged NICs significantly modifies the dispersion and amplification characteristics of LEK waves in magnetized GaN semiconductor plasma and their role becomes increasingly effective as the fraction of charge on them increases.

Propagation of electro-kinetic waves in magnetized GaN semiconductor with nano-sized ion colloids

International Nuclear Information System (INIS)

Saxena, Ajay; Sharma, Giriraj; Jat, K. L.; Rishi, M. P.

2015-01-01

Based on hydrodynamic model of multi-component plasma, an analytical study on propagation of longitudinal electro-kinetic (LEK) waves in wurtzite and zincblende structures of GaN is carried out. Nano-sized ion colloids (NICs) are embedded in the sample by the technique of ion-implantation. The implanted NICs are considered massive by an order as compared to the host lattice points and do not participate in Based LEK perturbations. Though, the NICs are continuously bombarded by the electrons as well as the holes yet, the former acquires a net negative charge owing to relatively higher mobility of electrons and consequently results into depletion of electron density in the medium. It i s found that the presence of charged NICs significantly modifies the dispersion and amplification characteristics of LEK waves in magnetized GaN semiconductor plasma and their role becomes increasingly effective as the fraction of charge on them increases

High-current power supply for accelerator magnets

International Nuclear Information System (INIS)

Bourkland, K.R.; Winje, R.A.

1978-01-01

A power supply for controlling the current to accelerator magnets produces a high current at a precisely controlled time rate of change by varying the resonant frequency of an RLC circuit that includes the magnet and applying the current to the magnet during a predetermined portion of the waveform of an oscillation. The current is kept from going negative despite the reverse-current characteristics of thyristors by a quenching circuit

Optimization of the lithium/thionyl chloride battery

Science.gov (United States)

White, Ralph E.

1989-01-01

A 1-D math model for the lithium/thionyl chloride primary cell is used in conjunction with a parameter estimation technique in order to estimate the electro-kinetic parameters of this electrochemical system. The electro-kinetic parameters include the anodic transfer coefficient and exchange current density of the lithium oxidation, alpha sub a,1 and i sub o,i,ref, the cathodic transfer coefficient and the effective exchange current density of the thionyl chloride reduction, alpha sub c,2 and a sup o i sub o,2,ref, and a morphology parameter, Xi. The parameter estimation is performed on simulated data first in order to gain confidence in the method. Data, reported in the literature, for a high rate discharge of an experimental lithium/thionyl chloride cell is used for an analysis.

Scale-up of the electrokinetic fence technology for the removal of pesticides. Part I: Some notes about the transport of inorganic species.

Science.gov (United States)

López-Vizcaíno, R; Risco, C; Isidro, J; Rodrigo, S; Saez, C; Cañizares, P; Navarro, V; Rodrigo, M A

2017-01-01

This work describes the application electrokinetic fence technology to a soil polluted with herbicides in a large prototype containing 32 m 3 of soil. It compares performance in this large facility with results previously obtained in a pilot-scale mockup (175 L) and with results obtained in a lab-scale soil column (1 L), all of them operated under the same driving force: an electric field of 1.0 V cm -1 . Within this wide context, this work focuses on the effect on inorganic species contained in soil and describes the main processes occurring in the prototype facility, as well as the differences observed respect to the lower scale plants. Thus, despite the same processes can be described in the three plants, important differences are observed in the evolution of the current intensity, moisture and conductivity. They can be related to the less important electroosmotic fluxes in the larger facilities and to the very different distances between electrodes, which lead to very different distribution of species and even to a very different evolution of the resulting current intensity. 2-D maps of the main species at different relevant moments of the test are discussed and important information is drawn from them. Ions depletion from soil appears as a very important problem which should be prevented if the effect of natural bioremediation and/or phytoremediation on the removal or organics aims to be accounted. Copyright © 2016 Elsevier Ltd. All rights reserved.

Modelling earth current precursors in earthquake prediction

Directory of Open Access Journals (Sweden)

R. Di Maio

1997-06-01

Full Text Available This paper deals with the theory of earth current precursors of earthquake. A dilatancy-diffusion-polarization model is proposed to explain the anomalies of the electric potential, which are observed on the ground surface prior to some earthquakes. The electric polarization is believed to be the electrokinetic effect due to the invasion of fluids into new pores, which are opened inside a stressed-dilated rock body. The time and space variation of the distribution of the electric potential in a layered earth as well as in a faulted half-space is studied in detail. It results that the surface response depends on the underground conductivity distribution and on the relative disposition of the measuring dipole with respect to the buried bipole source. A field procedure based on the use of an areal layout of the recording sites is proposed, in order to obtain the most complete information on the time and space evolution of the precursory phenomena in any given seismic region.

High current vacuum closing switch

International Nuclear Information System (INIS)

Dolgachev, G.I.; Maslennikov, D.D.; Romanov, A.S.; Ushakov, A.G.

2005-01-01

The paper proposes a powerful pulsed closing vacuum switch for high current commutation consisting of series of the vacuum diodes with near 1 mm gaps having closing time determined by the gaps shortening with the near-electrode plasmas [ru

High current density ion beam measurement techniques

International Nuclear Information System (INIS)

Ko, W.C.; Sawatzky, E.

1976-01-01

High ion beam current measurements are difficult due to the presence of the secondary particles and beam neutralization. For long Faraday cages, true current can be obtained only by negative bias on the target and by summing the cage wall and target currents; otherwise, the beam will be greatly distorted. For short Faraday cages, a combination of small magnetic field and the negative target bias results in correct beam current. Either component alone does not give true current

High field, low current operation of engineering test reactors

International Nuclear Information System (INIS)

Schwartz, J.; Cohn, D.R.; Bromberg, L.; Williams, J.E.C.

1987-06-01

Steady state engineering test reactors with high field, low current operation are investigated and compared to high current, lower field concepts. Illustrative high field ETR parameters are R = 3 m, α ∼ 0.5 m, B ∼ 10 T, β = 2.2% and I = 4 MA. For similar wall loading the fusion power of an illustrative high field, low current concept could be about 50% that of a lower field device like TIBER II. This reduction could lead to a 50% decrease in tritium consumption, resulting in a substantial decrease in operating cost. Furthermore, high field operation could lead to substantially reduced current drive requirements and cost. A reduction in current drive source power on the order of 40 to 50 MW may be attainable relative to a lower field, high current design like TIBER II implying a possible cost savings on the order of $200 M. If current drive is less efficient than assumed, the savings could be even greater. Through larger β/sub p/ and aspect ratio, greater prospects for bootstrap current operation also exist. Further savings would be obtained from the reduced size of the first wall/blanket/shield system. The effects of high fields on magnet costs are very dependent on technological assumptions. Further improvements in the future may lie with advances in superconducting and structural materials

Highly efficient red electrophosphorescent devices at high current densities

International Nuclear Information System (INIS)

Wu Youzhi; Zhu Wenqing; Zheng Xinyou; Sun, Runguang; Jiang Xueyin; Zhang Zhilin; Xu Shaohong

2007-01-01

Efficiency decrease at high current densities in red electrophosphorescent devices is drastically restrained compared with that from conventional electrophosphorescent devices by using bis(2-methyl-8-quinolinato)4-phenylphenolate aluminum (BAlq) as a hole and exciton blocker. Ir complex, bis(2-(2'-benzo[4,5-α]thienyl) pyridinato-N,C 3' ) iridium (acetyl-acetonate) is used as an emitter, maximum external quantum efficiency (QE) of 7.0% and luminance of 10000cd/m 2 are obtained. The QE is still as high as 4.1% at higher current density J=100mA/cm 2 . CIE-1931 co-ordinates are 0.672, 0.321. A carrier trapping mechanism is revealed to dominate in the process of electroluminescence

Simple, high current, antimony ion source

International Nuclear Information System (INIS)

Sugiura, H.

1979-01-01

A simple metal ion source capable of producing a continuous, uncontaminated, high current beam of Sb ions is presented. It produced a total ion current of 200 μA at 1 kV extraction voltage. A discharge occurred in the source at a pressure of 6 x 10 -4 Torr. The ion current extracted from the source increased with the 3/2 power of the extraction voltage. The perveance of the source and ion density in the plasma were 8 x 10 -9 and 1.8 x 10 11 cm -3 , respectively

Thrombin Production and Human Neutrophil Elastase Sequestration by Modified Cellulosic Dressings and Their Electrokinetic Analysis

Directory of Open Access Journals (Sweden)

Nicolette Prevost

2011-12-01

Full Text Available Wound healing is a complex series of biochemical and cellular events. Optimally, functional material design addresses the overlapping acute and inflammatory stages of wound healing based on molecular, cellular, and bio-compatibility issues. In this paper the issues addressed are uncontrolled hemostasis and inflammation which can interfere with the orderly flow of wound healing. In this regard, we review the serine proteases thrombin and elastase relative to dressing functionality that improves wound healing and examine the effects of charge in cotton/cellulosic dressing design on thrombin production and elastase sequestration (uptake by the wound dressing. Thrombin is central to the initiation and propagation of coagulation, and elastase is released from neutrophils that can function detrimentally in a stalled inflammatory phase characteristic of chronic wounds. Electrokinetic fiber surface properties of the biomaterials of this study were determined to correlate material charge and polarity with function relative to thrombin production and elastase sequestration. Human neutrophil elastase sequestration was assessed with an assay representative of chronic wound concentration with cotton gauze cross-linked with three types of polycarboxylic acids and one phosphorylation finish; thrombin production, which was assessed in a plasma-based assay via a fluorogenic peptide substrate, was determined for cotton, cotton-grafted chitosan, chitosan, rayon/polyester, and two kaolin-treated materials including a commercial hemorrhage control dressing (QuickClot Combat Gauze. A correlation in thrombin production to zeta potential was found. Two polycarboxylic acid cross linked and a phosphorylated cotton dressing gave high elastase sequestration.

Potentiometric and electrokinetic signatures of iron(II) interactions with (α,γ)-Fe2O3.

Science.gov (United States)

Toczydłowska, Diana; Kędra-Królik, Karolina; Nejbert, Krzysztof; Preočanin, Tajana; Rosso, Kevin M; Zarzycki, Piotr

2015-10-21

The electrochemical signatures of Fe(II) interactions with iron(III) oxides are poorly understood, despite their importance in controlling the amount of mobilized iron. Here, we report the potentiometric titration of α,γ-Fe2O3 oxides exposed to Fe(II) ions. We monitored in situ surface and ζ potentials, the ratio of mobilized ferric to ferrous, and the periodically analyzed nanoparticle crystal structure using X-ray diffraction. Electrokinetic potential reveals weak but still noticeable specific sorption of Fe(II) to the oxide surface under acidic conditions, and pronounced adsorption under alkaline conditions that results in a surface potential reversal. By monitoring the aqueous iron(II/III) fraction, we found that the addition of Fe(II) ions produces platinum electrode response consistent with the iron solubility-activity curve. Although, XRD analysis showed no evidence of γ-Fe2O3 transformations along the titration pathway despite iron cycling between aqueous and solid reservoirs, the magnetite formation cannot be ruled out.

Electro-Kinetic Pumping with Slip Irreversibility in Heat Exchange of CSP-Powered Bio-Digester Assemblies

Directory of Open Access Journals (Sweden)

Emmanuel O.B. Ogedengbe

2012-12-01

Full Text Available Parametric studies of the effects of slip irreversibility in concentrating solar power (CSP-powered bio-digester assemblies are investigated. Complexities regarding the identification of the appropriate electro-kinetic phenomena for certain electrolyte phases are reviewed. The application of exergy analysis to the design of energy conversion devices, like solar thermal collectors, for the required heat of formation in a downdraft waste food bio-digester, is discussed. Thermal management in the silicon-based substrate of the energy system is analyzed. The rectangular-shaped micro-channels are simulated with a finite-volume, staggered coupling of the pressure-velocity fields. Entropy generation transport within the energy system is determined and coupled with the solution procedure. Consequently, the effects of channel size perturbation, Reynolds number, and pressure ratios on the thermal performance and exergy destruction are presented. A comparative analysis of the axial heat conduction for thermal management in energy conversion devices is proposed.

High-current discharge channel contraction in high density gas

International Nuclear Information System (INIS)

Rutberg, Ph. G.; Bogomaz, A. A.; Pinchuk, M. E.; Budin, A. V.; Leks, A. G.; Pozubenkov, A. A.

2011-01-01

Research results for discharges at current amplitudes of 0.5-1.6 MA and current rise rate of ∼10 10 A/s are presented. The discharge is performed in the hydrogen environment at the initial pressure of 5-35 MPa. Initiation is implemented by a wire explosion. The time length of the first half-period of the discharge current is 70-150 μs. Under such conditions, discharge channel contraction is observed; the contraction is followed by soft x-ray radiation. The phenomena are discussed, which are determined by high density of the gas surrounding the discharge channel. These phenomena are increase of the current critical value, where the channel contraction begins and growth of temperature in the axis region of the channel, where the initial density of the gas increases.

Optimisation methodology in the chiral and achiral separation in electrokinetic chromatography in the case of a multicomponent sample of dansyl amino acids.

Science.gov (United States)

Giuffrida, Alessandro; Messina, Marianna; Contino, Annalinda; Cucinotta, Vincenzo

2013-11-01

Two different chiral selectors synthesised in our laboratory were used to test the possibility of separation for a sample consisting of ten different enantiomeric pairs of dansyl-derivatives of α-amino acids in electrokinetic chromatography. It was possible to observe all the peaks, though only partly resolved, due to the twenty analytes through an accurate strategy of choice of the experimental conditions. As a part of this strategy, a procedure of identification of the single peaks in the electropherograms called LACI (lastly added component identification) has been developed. Copyright © 2013 Elsevier B.V. All rights reserved.

Rapid determination of piracetam in human plasma and cerebrospinal fluid by micellar electrokinetic chromatography with sample direct injection.

Science.gov (United States)

Yeh, Hsin-Hua; Yang, Yuan-Han; Ko, Ju-Yun; Chen, Su-Hwei

2006-07-07

A simple micellar electrokinetic chromatography (MEKC) method with UV detection at 200 nm for analysis of piracetam in plasma and in cerebrospinal fluid (CSF) by direct injection without any sample pretreatment is described. The separation of piracetam from biological matrix was performed at 25 degrees C using a background electrolyte consisting of Tris buffer with sodium dodecyl sulfate (SDS) as the electrolyte solution. Several parameters affecting the separation of the drug from biological matrix were studied, including the pH and concentrations of the Tris buffer and SDS. Under optimal MEKC condition, good separation with high efficiency and short analyses time is achieved. Using imidazole as an internal standard (IS), the linear ranges of the method for the determination of piracetam in plasma and in CSF were all between 5 and 500 microg/mL; the detection limit of the drug in plasma and in CSF (signal-to-noise ratio=3; injection 0.5 psi, 5s) was 1.0 microg/mL. The applicability of the proposed method for determination of piracetam in plasma and CSF collected after intravenous administration of 3g piracetam every 6h and oral administration 1.2g every 6h in encephalopathy patients with aphasia was demonstrated.

Compact high-current, subnanosecond electron accelerator

Energy Technology Data Exchange (ETDEWEB)

Shpak, V G; Shunajlov, S A; Ulmaskulov, M R; Yalandin, M I [Russian Academy of Sciences, Ekaterinburg (Russian Federation). Inst. of Electrophysics; Pegel, I V [Russian Academy of Sciences, Tomsk (Russian Federation). High-Current Electronics Inst.; Tarakanov, V P [Russian Academy of Sciences, Moscow (Russian Federation). High-Temperature Inst.

1997-12-31

A compact subnanosecond, high-current electron accelerator producing an annular electron beam of duration up to 300 - 400 ps, energy about 250 keV, and current up to 1 kA has been developed to study transient processes in pulsed power microwave devices. The measuring and recording techniques used to experimentally investigate the dynamics of the beam current pulse and the transformation of the electron energy during the transportation of the beam in a longitudinal magnetic field are described. The experimental data obtained are compared with the predictions of a numerical simulation. (author). 6 figs., 5 refs.

Development of a high current ion implanter

International Nuclear Information System (INIS)

Choi, Byung Ho; Kim, Wan; Jin, Jeong Tae

1990-01-01

A high current ion implanter of the energy of 100 Kev and the current of about 100 mA has been developed for using the high dose ion implantation, surface modification of steels and ceramics, and ion beam milling. The characteristics of the beam extraction and transportation are investigated. A duoPIGatron ion source compatible with gas ion extraction of about 100 mA, a single gap acceleration tube which is able to compensate the divergence due to the space charge effect, and a beam transport system with the concept of the space charge neutralization are developed for the high current machine. The performance of the constructed machine shows that nitrogen, argon, helium, hydrogen and oxygen ion beams are successfully extracted and transported at a beam divergence due to space charge effect is negligible in the operation pressure of 2 x 10 -5 torr. (author)

Stable superconducting magnet. [high current levels below critical temperature

Science.gov (United States)

Boom, R. W. (Inventor)

1967-01-01

Operation of a superconducting magnet is considered. A method is described for; (1) obtaining a relatively high current in a superconducting magnet positioned in a bath of a gas refrigerant; (2) operating a superconducting magnet at a relatively high current level without training; and (3) operating a superconducting magnet containing a plurality of turns of a niobium zirconium wire at a relatively high current level without training.

A high current, high speed pulser using avalanche transistors

International Nuclear Information System (INIS)

Hosono, Yoneichi; Hasegawa, Ken-ichi

1985-01-01

A high current, high speed pulser for the beam pulsing of a linear accelerator is described. It uses seven avalanche transistors in cascade. Design of a trigger circuit to obtain fast rise time is discussed. The characteristics of the pulser are : (a) Rise time = 0.9 ns (FWHM) and (d) Life time asymptotically equals 2000 -- 3000 hr (at 50 Hz). (author)

Enhance soil bioremediation with electric fields

International Nuclear Information System (INIS)

Acar, Y.B.; Rabbi, M.F.; Gale, R.J.; Ozsu, E.E.; Alshawabkeh, A.N.

1996-01-01

Electrokinetic remediation is an in situ remediation technique that uses low-level direct-current electric potential differences (on the order of volts per centimeter) or an electric current (on the order of milliamps per square centimeter of cross-sectional area between electrodes) applied across a soil mass by electrodes placed in an open- or closed-flow arrangement. In electrokinetic methods, the groundwater in the boreholes or an externally supplied fluid (processing fluid) is used as the conductive medium. Electrokinetic remediation technology for metal extraction is expected to decrease the cost of remediating contaminated soils to the lower end of the $100--$1,000/m 3 range. This would be a significant savings in the $350 billion hazardous waste site cleanup and remediation market. The environmental restoration cost for the mixed (radioactive)-waste market is separately estimated to be $65 billion. The potential of the electrokinetic remediation technique in remediating soils contaminated with radioactive mixed waste using depolarization agents and complexing agents is noteworthy. The authors have removed uranyl ions from spiked kaolinite using the technique

Rapid determination of water- and fat-soluble vitamins with microemulsion electrokinetic chromatography.

Science.gov (United States)

Yin, Changna; Cao, Yuhua; Ding, Shaodong; Wang, Yun

2008-06-06

A rapid, reliable and reproducible method based on microemulsion electrokinetic chromatography (MEEKC) for simultaneous determination of 13 kinds of water- and fat-soluble vitamins has been developed in this work. A novel microemulsion system consisting of 1.2% (w/w) sodium lauryl sulphate (SDS), 21% (v/v) 1-butanol, 18% (v/v) acetonitrile, 0.8% (w/w) n-hexane, 20mM borax buffer (pH 8.7) was applied to improve selectivity and efficiency, as well as shorten analysis time. The composition of microemulsion used as the MEEKC running buffer was investigated thoroughly to obtain stable separation medium, as well as the optimum determination conditions. Acetonitrile as the organic solvent modifier, pH of the running buffer and 1-butanol as the co-surfactant played the most important roles for the separation of the fat-soluble vitamins, water-soluble vitamins and stabilization of system, respectively. The 13 water- and fat-soluble vitamins were baseline separated within 30 min. The system was applied to determine water- and fat-soluble vitamins in commercial multivitamin pharmaceutical formulation, good accuracy and precision were obtained with recoveries between 97% and 105%, relative standard derivations (RSDs) less than 1.8% except vitamin C, and acceptable quantitative results corresponding to label claim.

Analysis of Dyes Extracted from Millimeter-Size Nylon Fibers by Micellar Electrokinetic Chromatography

International Nuclear Information System (INIS)

Lewis, L.A.

2001-01-01

The Learning Objective is to present to the forensic community a potential qualitative/quantitative method for trace-fiber color comparisons using micellar electrokinetic chromatography (MEKC). Developing a means of analyzing extracted dye constituents from millimeter-size nylon fiber samples was the objective of this research initiative. Aside from ascertaining fiber type, color evaluation and source comparison of trace-fiber evidence plays a critical role in forensic-fiber examinations. Literally thousands of dyes exist to date, including both natural and synthetic compounds. Typically a three-color-dye combination is employed to affect a given color on fiber material. The result of this practice leads to a significant number of potential dye combinations capable of producing a similar color and shade. Since a typical forensic fiber sample is 2 mm or less in length, an ideal forensic dye analysis would qualitatively and quantitatively identify the extracted dye constituents from a sample size of 1 mm or smaller. The goal of this research was to develop an analytical method for comparing individual dye constituents from trace-fiber evidence with dyes extracted from a suspected source, while preserving as much of the original evidence as possible

Influence of buffer zone concentrations on efficiency in partial filling micellar electrokinetic chromatography.

Science.gov (United States)

Michalke, D; Kolb, S; Welsch, T

2001-05-04

The potential of counter pressure-moderated partial filling micellar electrokinetic chromatography (PF-MEKC) was investigated in this work. Plate numbers of homologous omega-phenylalcohols were measured in a two-plug PF-MEKC system varying the concentrations and hence the ionic strengths of the background buffer compared to the sodium dodecyl sulfate-containing separation buffer and the counter pressure on the cathodic buffer reservoir. It was observed that plate numbers are strongly influenced by both the buffer concentrations and the counter pressure. Highest plate numbers were obtained with a buffer system where the concentrations are adjusted such that the electroosmotic flow velocities in both zones are equal. Differences in the local electroosmotic flow velocities of the zones caused by different buffer concentrations are responsible for tremendously reduced plate numbers. The efficiency drop is explained in several models by the formation of an intersegmental pressure which produces a parabolically shaped laminar flow component in both zones. Thus, the electroosmotic plug-like flow profile is distorted and the efficiency is reduced. The effect of counter pressure on efficiency turned out to be very complex in dependence on the buffer system applied.

Experimental design for assessment of electrokinetically enhanced delivery of lactate and bacteria in 1,2-cis-dichloroethylene contaminated limestone

DEFF Research Database (Denmark)

Hyldegaard, Bente Højlund; Nedergaard, L. W.; Ottosen, Lisbeth

2015-01-01

Bacterial dechlorination of chlorinated solvents often causes accumulation of the intermediate cis-DCE. Back diffusion of e.g. cis-DCE, due to the dual porosity of limestone, often limits the remediation efficiency. A remediation scheme capable of establishing contact between contaminant, degrading...... bacteria and electron donor within the low permeable limestone matrix is required. The technology EK-BIO, which combines enhanced reductive dechlorination and electrokinetics (EK), was assessed. This novel technology has not previously been tested in limestone. An experimental set-up was designed to meet...... that fermentative bacteria were distributed by electrophoresis. This study suggests that EK application can establish the essential contact and overcome back diffusion. Thereby, EK-BIO may be superior to advection-based technologies for bioremediation of chlorinated solvent contaminated limestone matrices....

Transmission Level High Temperature Superconducting Fault Current Limiter

Energy Technology Data Exchange (ETDEWEB)

Stewart, Gary [SuperPower, Inc., Schenectady, NY (United States)

2016-10-05

The primary objective of this project was to demonstrate the feasibility and reliability of utilizing high-temperature superconducting (HTS) materials in a Transmission Level Superconducting Fault Current Limiter (SFCL) application. During the project, the type of high-temperature superconducting material used evolved from 1^st generation (1G) BSCCO-2212 melt cast bulk high-temperature superconductors to 2^nd generation (2G) YBCO-based high-temperature superconducting tape. The SFCL employed SuperPower's “Matrix” technology, that offers modular features to enable scale up to transmission voltage levels. The SFCL consists of individual modules that contain elements and parallel inductors that assist in carrying the current during the fault. A number of these modules are arranged in an m x n array to form the current-limiting matrix.

High current transistor pulse generator

International Nuclear Information System (INIS)

Nesterov, V.; Cassel, R.

1991-05-01

A solid state pulse generator capable of delivering high current trapezoidally shaped pulses into an inductive load has been developed at SLAC. Energy stored in the capacitor bank of the pulse generator is switched to the load through a pair of Darlington transistors. A combination of diodes and Darlington transistors is used to obtain trapezoidal or triangular shaped current pulses into an inductive load and to recover the remaining energy in the same capacitor bank without reversing capacitor voltage. The transistors work in the switch mode, and the power losses are low. The rack mounted pulse generators presently used at SLAC contain a 660 microfarad storage capacitor bank and can deliver 400 amps at 800 volts into inductive loads up to 3 mH. The pulse generators are used in several different power systems, including pulse to pulse bipolar power supplies and in application with current pulses distributed into different inductive loads. The current amplitude and discharge time are controlled by the central computer system through a specially developed multichannel controller. Several years of operation with the pulse generators have proven their consistent performance and reliability. 8 figs

Lattice Effects Due to High Currents in PEP-II

International Nuclear Information System (INIS)

Decker, F.-J.; Smith, H.; Turner, J.L.; SLAC

2005-01-01

The very high beam currents in the PEP-II B-Factory have caused many expected and unexpected effects: Synchrotron light fans move the beam pipe and cause dispersion; higher order modes cause excessive heating, e-clouds around the positron beam blow up its beam size. Here we describe an effect where the measured dispersion of the beam in the Low Energy Ring (LER) is different at high and at low beam currents. The dispersion was iteratively lowered by making anti-symmetric orbit bumps in many sextupole duplets, checking each time with a dispersion measurement where a dispersive kick is generated. This can be done parasitically during collisions. It was a surprise when checking the low current characterization data that there is a change. Subsequent high and low current measurements confirmed the effect. One source was believed to be located far away from any synchrotron radiation in the middle of a straight (PR12), away from sextupoles and skew quadrupoles and created a dispersion wave of about 70 mm at high current while at low current it is negligible

LASL high-current proton storage rings

International Nuclear Information System (INIS)

Lawrence, G.P.; Cooper, R.K.; Hudgings, D.W.; Spalek, G.; Jason, A.J.; Higgins, E.F.; Gillis, R.E.

1980-01-01

The Proton Storage Ring at LAMPF is a high-current accumulator designed to convert long 800-MeV linac pulses into very short high-intensity proton bunches ideally suited to driving a pulsed polyenergetic neutron source. The Ring, authorized for construction at $19 million, will operate in a short-bunch high-frequency mode for fast neutron physics and a long-bunch low-frequency mode for thermal neutron-scattering programs. Unique features of the project include charge-changing injection with initial conversion from H - to H 0 , a high repetition rate fast-risetime extraction kicker, and high-frequency and first-harmonic bunching system

High resolution eddy current microscopy

Science.gov (United States)

Lantz, M. A.; Jarvis, S. P.; Tokumoto, H.

2001-01-01

We describe a sensitive scanning force microscope based technique for measuring local variations in resistivity by monitoring changes in the eddy current induced damping of a cantilever with a magnetic tip oscillating above a conducting sample. To achieve a high sensitivity, we used a cantilever with an FeNdBLa particle mounted on the tip. Resistivity measurements are demonstrated on a silicon test structure with a staircase doping profile. Regions with resistivities of 0.0013, 0.0041, and 0.022 Ω cm are clearly resolved with a lateral resolution of approximately 180 nm. For this range of resistivities, the eddy current induced damping is found to depend linearly on the sample resistivity.

Research factors of the electrochemical remediation clay soils from the nitrates

Energy Technology Data Exchange (ETDEWEB)

Korolev, V.A.; Babakina, O.A. [Moscow State Univ. (Russian Federation)

2001-07-01

The electrokinetic's methods are prevalent [1, 2], but abilities of the method for remediation nitrates contaminated soils are studied insufficiently. The investigations of effectiveness electrochemical remediation are complicated by processes of reduction nitrates to nitrites (that are more toxic) and then to nitrogen in soil under the constant electric current. Therefore, the objectives of the research was following: - Evaluate mechanism of electrokinetic's removing nitrates from soil; - Evaluate basic value of moisture and alkalinity influence for electrochemical remediation of soil from nitrates; - Determine flow-through regime effect on electrokinetic's treating. (orig.)

Surface ionization ion source with high current

International Nuclear Information System (INIS)

Fang Jinqing; Lin Zhizhou; Yu Lihua; Zhan Rongan; Huang Guojun; Wu Jianhua

1986-04-01

The working principle and structure of a surface ionization ion source with high current is described systematically. Some technological keypoints of the ion source are given in more detail, mainly including: choosing and shaping of the material of the surface ionizer, heating of the ionizer, distributing of working vapour on the ionizer surface, the flow control, the cooling problem at the non-ionization surface and the ion optics, etc. This ion source has been used since 1972 in the electromagnetic isotope separator with 180 deg angle. It is suitable for separating isotopes of alkali metals and rare earth metals. For instance, in the case of separating Rubidium, the maximum ion current of Rbsup(+) extracted from the ion source is about 120 mA, the maximum ion current accepted by the receiver is about 66 mA, the average ion current is more than 25 mA. The results show that our ion source have advantages of high ion current, good characteristics of focusing ion beam, working stability and structure reliability etc. It may be extended to other fields. Finally, some interesting phenomena in the experiment are disccused briefly. Some problems which should be investigated are further pointed out

Robust analysis of the hydrophobic basic analytes loratadine and desloratadine in pharmaceutical preparations and biological fluids by sweeping-cyclodextrin-modified micellar electrokinetic chromatography.

Science.gov (United States)

El-Awady, Mohamed; Belal, Fathalla; Pyell, Ute

2013-09-27

The analysis of hydrophobic basic analytes by micellar electrokinetic chromatography (MEKC) is usually challenging because of the tendency of these analytes to be adsorbed onto the inner capillary wall in addition to the difficulty to separate these compounds as they exhibit extremely high retention factors. A robust and reliable method for the simultaneous determination of loratadine (LOR) and its major metabolite desloratadine (DSL) is developed based on cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC) with acidic sample matrix and basic background electrolyte (BGE). The influence of the sample matrix on the reachable focusing efficiency is studied. It is shown that the application of a low pH sample solution mitigates problems associated with the low solubility of the hydrophobic basic analytes in aqueous solution while having advantages with regard to on-line focusing. Moreover, the use of a basic BGE reduces the adsorption of these analytes in the separation compartment. The separation of the studied analytes is achieved in less than 7min using a BGE consisting of 10mmolL(-1) disodium tetraborate buffer, pH 9.30 containing 40mmolL(-1) SDS and 20mmolL(-1) hydroxypropyl-β-CD while the sample solution is composed of 10mmolL(-1) phosphoric acid, pH 2.15. A full validation study of the developed method based on the pharmacopeial guidelines is performed. The method is successfully applied to the analysis of the studied drugs in tablets without interference of tablet additives as well as the analysis of spiked human urine without any sample pretreatment. Furthermore, DSL can be detected as an impurity in LOR bulk powder at the stated pharmacopeial limit (0.1%, w/w). The selectivity of the developed method allows the analysis of LOR and DSL in combination with the co-formulated drug pseudoephedrine. It is shown that in CD-MEKC with basic BGE, solute-wall interactions are effectively suppressed allowing the development of efficient and precise

Critical current enhancement in high Tc superconductors

International Nuclear Information System (INIS)

Jin, S.; Graebner, J.E.; Tiefel, T.H.

1990-01-01

Progress toward major technological applications of the bulk, high T c superconductors has been hindered by two major barriers, i.e., the Josephson weak-links at grain boundaries and the lack of sufficient intragrain flux pinning. It has been demonstrated that the weak link problem can be overcome by extreme alignment of grains such as in melt-textured-growth (MTG) materials. Modified or improved processing by various laboratories has produced further increased critical currents. However, the insufficient flux pinning seems to limit the critical current density in high fields to about 10 4 --10 5 A/cm 2 at 77K, which is not satisfactory for many applications. In this paper, processing, microstructure, and critical current behavior of the MTG type superconductors are described, and various processing possibilities for flux pinning enhancement are discussed

Elemental composition study of heavy metal (Ni, Cu, Zn) in riverbank soil by electrokinetic-assisted phytoremediation using XRF and SEM/EDX

International Nuclear Information System (INIS)

Jamari, Suhailly; Embong, Zaidi; Bakar, Ismail

2014-01-01

Electrokinetic (EK)-assisted phytoremediation is one of the methods that have a big potential in enhancing the ability of plant uptake in soils remediation process. This research was conducted to investigate the difference in elemental composition concentration of riverbank soil and the change of pH between pre- and post-phytoremediation under the following condition: 1) control or as-receive sample; 2) Dieffenbachia spp plant with EK system (a pair of EK electrodes connected to a direct current (DC) power supply). After the electrodes were connected to a magnitude of 6V/cm −1 electric field for 4 hours/day, the soil and plant samples were analyzed using and X-ray Fluorescence Spectrometer (XRF) and Scanning Electron Microscope / Energy Dispersive X-ray Spectroscopy (SEM/EDX). The SEM/EDX analysis showed that concentration of elemental composition (Ni, Cu and Zn) in post-phytoremediation plant powder samples had increase while elemental concentrations in the post-phytoremediation soil samples were decreased. XRF analysis presented a variation in soil elemental composition concentration from anode to cathode where the concentration near anode region increased while decreased near the cathode region. A significant changes in soil pH were obtained where the soil pH increase in cathode region while decrease in anode region. The results reveal that the assistance of EK in phytoremediation process has increase the efficiency of plant uptake

Elemental composition study of heavy metal (Ni, Cu, Zn) in riverbank soil by electrokinetic-assisted phytoremediation using XRF and SEM/EDX

Energy Technology Data Exchange (ETDEWEB)

Jamari, Suhailly [Faculty of Science, Technology and Human Development, Universiti Tun Hussein Onn Malaysia (UTHM) (Malaysia); Embong, Zaidi [Faculty of Science, Technology and Human Development, Universiti Tun Hussein Onn Malaysia (UTHM) and Research Center for Soft Soils (RECESS), Office of Research, Innovation, Commercialization and Consultancy Management - ORRIC, Universiti Tun Hussein (Malaysia); Bakar, Ismail [Research Center for Soft Soils (RECESS), Office of Research, Innovation, Commercialization and Consultancy Management (ORRIC), Universiti Tun Hussein Onn Malaysia -UTHM, 86400 Batu Pahat, Johor (Malaysia)

2014-02-12

Electrokinetic (EK)-assisted phytoremediation is one of the methods that have a big potential in enhancing the ability of plant uptake in soils remediation process. This research was conducted to investigate the difference in elemental composition concentration of riverbank soil and the change of pH between pre- and post-phytoremediation under the following condition: 1) control or as-receive sample; 2) Dieffenbachia spp plant with EK system (a pair of EK electrodes connected to a direct current (DC) power supply). After the electrodes were connected to a magnitude of 6V/cm{sup −1} electric field for 4 hours/day, the soil and plant samples were analyzed using and X-ray Fluorescence Spectrometer (XRF) and Scanning Electron Microscope / Energy Dispersive X-ray Spectroscopy (SEM/EDX). The SEM/EDX analysis showed that concentration of elemental composition (Ni, Cu and Zn) in post-phytoremediation plant powder samples had increase while elemental concentrations in the post-phytoremediation soil samples were decreased. XRF analysis presented a variation in soil elemental composition concentration from anode to cathode where the concentration near anode region increased while decreased near the cathode region. A significant changes in soil pH were obtained where the soil pH increase in cathode region while decrease in anode region. The results reveal that the assistance of EK in phytoremediation process has increase the efficiency of plant uptake.

Quantification of the level of fat-soluble vitamins in feed based on the novel microemulsion electrokinetic chromatography (MEEKC) method.

Science.gov (United States)

Olędzka, Ilona; Kowalski, Piotr; Bałuch, Alicja; Bączek, Tomasz; Paradziej-Łukowicz, Jolanta; Taciak, Marcin; Pastuszewska, Barbara

2014-02-01

Simultaneous quantification of liposoluble vitamins is not a new area of interest, since these compounds co-determine the nutritional quality of food and feed, a field widely explored in the human and animal diet. However, the development of appropriate methods is still a matter of concern, especially when the vitamin composition is highly complex, as is the case with feed designated for laboratory animals, representing a higher health and microbiological status. A method combining microemulsion electrokinetic chromatography (MEEKC) with liquid-liquid extraction was developed for the determination of four fat-soluble vitamins in animal feed. A separation medium consisting of 25 mmol L⁻¹ phosphate buffer (pH 2.5), 2-propanol, 1-butanol, sodium dodecyl sulfate and octane allowed the simultaneous determination of vitamins A, D, E and K within a reasonable time of 25 min. The polarity of the separation voltage was reversed in view of the strongly suppressed electro-osmotic flow, and the applied voltage was set at 12 kV. The fat-soluble vitamins were separated in the order of decreasing hydrophobicity. It was proved that the proposed MEEKC method was sufficiently specific and sensitive for screening fat-soluble vitamins in animal feed samples after their sterilization. © 2013 Society of Chemical Industry.

High current high accuracy IGBT pulse generator

International Nuclear Information System (INIS)

Nesterov, V.V.; Donaldson, A.R.

1995-05-01

A solid state pulse generator capable of delivering high current triangular or trapezoidal pulses into an inductive load has been developed at SLAC. Energy stored in a capacitor bank of the pulse generator is switched to the load through a pair of insulated gate bipolar transistors (IGBT). The circuit can then recover the remaining energy and transfer it back to the capacitor bank without reversing the capacitor voltage. A third IGBT device is employed to control the initial charge to the capacitor bank, a command charging technique, and to compensate for pulse to pulse power losses. The rack mounted pulse generator contains a 525 μF capacitor bank. It can deliver 500 A at 900V into inductive loads up to 3 mH. The current amplitude and discharge time are controlled to 0.02% accuracy by a precision controller through the SLAC central computer system. This pulse generator drives a series pair of extraction dipoles

New Pulsed Power Technology for High Current Accelerators

International Nuclear Information System (INIS)

Caporaso, G J

2002-01-01

Recent advances in solid-state modulators now permit the design of a new class of high current accelerators. These new accelerators will be able to operate in burst mode at frequencies of several MHz with unprecedented flexibility and precision in pulse format. These new modulators can drive accelerators to high average powers that far exceed those of any other technology and can be used to enable precision beam manipulations. New insulator technology combined with novel pulse forming lines and switching may enable the construction of a new type of high gradient, high current accelerator. Recent developments in these areas will be reviewed

Physics issues of high bootstrap current tokamaks

International Nuclear Information System (INIS)

Ozeki, T.; Azumi, M.; Ishii, Y.

1997-01-01

Physics issues of a tokamak plasma with a hollow current profile produced by a large bootstrap current are discussed based on experiments in JT-60U. An internal transport barrier for both ions and electrons was obtained just inside the radius of zero magnetic shear in JT-60U. Analysis of the toroidal ITG microinstability by toroidal particle simulation shows that weak and negative shear reduces the toroidal coupling and suppresses the ITG mode. A hard beta limit was observed in JT-60U negative shear experiments. Ideal MHD mode analysis shows that the n = 1 pressure-driven kink mode is a plausible candidate. One of the methods to improve the beta limit against the kink mode is to widen the negative shear region, which can induce a broader pressure profile resulting in a higher beta limit. The TAE mode for the hollow current profile is less unstable than that for the monotonic current profile. The reason is that the continuum gaps near the zero shear region are not aligned when the radius of q min is close to the region of high ∇n e . Finally, a method for stable start-up for a plasma with a hollow current profile is describe, and stable sustainment of a steady-state plasma with high bootstrap current is discussed. (Author)

Chiral separation of amino acids in biological fluids by micellar electrokinetic chromatography with laser-induced fluorescence detection.

Science.gov (United States)

Thorsén, G; Bergquist, J

2000-08-18

A method is presented for the chiral analysis of amino acids in biological fluids using micellar electrokinetic chromatography (MEKC) and laser-induced fluorescence (LIF). The amino acids are derivatized with the chiral reagent (+/-)-1-(9-anthryl)-2-propyl chloroformate (APOC) and separated using a mixed micellar separation system. No tedious pre-purification of samples is required. The excellent separation efficiency and good detection capabilities of the MEKC-LIF system are exemplified in the analysis of urine and cerebrospinal fluid. This is the first time MEKC has been reported for chiral analysis of amino acids in biological fluids. The amino acids D-alanine, D-glutamine, and D-aspartic acid have been observed in cerebrospinal fluid, and D-alanine and D-glutamic acid in urine. To the best of our knowledge no measurements of either D-alanine in cerebrospinal fluid or D-glutamic acid in urine have been presented in the literature before.

Development and Testing of High Current Hollow Cathodes for High Power Hall Thrusters

Science.gov (United States)

Kamhawi, Hani; Van Noord, Jonathan

2012-01-01

NASA's Office of the Chief Technologist In-Space Propulsion project is sponsoring the testing and development of high power Hall thrusters for implementation in NASA missions. As part of the project, NASA Glenn Research Center is developing and testing new high current hollow cathode assemblies that can meet and exceed the required discharge current and life-time requirements of high power Hall thrusters. This paper presents test results of three high current hollow cathode configurations. Test results indicated that two novel emitter configurations were able to attain lower peak emitter temperatures compared to state-of-the-art emitter configurations. One hollow cathode configuration attained a cathode orifice plate tip temperature of 1132 degC at a discharge current of 100 A. More specifically, test and analysis results indicated that a novel emitter configuration had minimal temperature gradient along its length. Future work will include cathode wear tests, and internal emitter temperature and plasma properties measurements along with detailed physics based modeling.

High-current electron accelerator for gas-laser pumping

Energy Technology Data Exchange (ETDEWEB)

Badaliants, G R; Mamikonian, V A; Nersisian, G Ts; Papanian, V O

1978-11-26

A high-current source of pulsed electron beams has been developed for the pumping of UV gas lasers. The parameters of the device are: energy of 0.3-0.7 MeV pulse duration of 30 ns and current density (in a high-pressure laser chamber) of 40-100 A/sq cm. The principal feature of the device is the use of a rectangular cold cathode with incomplete discharge along the surface of the high-permittivity dielectric. Cathodes made of stainless steel, copper, and graphite were investigated.

Characteristics of a High Current Helicon Ion Source With High Monatomic Fraction

International Nuclear Information System (INIS)

Jung, Hwa-Dong; Chung, Kyoung-Jae; Hwang, Yong-Seok

2006-01-01

Applications of neutron need compact and high yield neutron sources as well as very intense neutron sources from giant devices such as accelerators. Ion source based neutron sources using nuclear fusion reactions such as D(d, 3He)n, D(t, 4He)n can meet the requirements. This type of neutron generators can be simply composed of an ion source and a target. High-performance neutron generators with high yield require ion sources with high beam current, high monatomic fraction and long lifetime. Helicon ion source can meet these requirements. To make high current ion source, characteristics of helicon plasma such as high plasma density can be utilized. Moreover, efficient plasma heating with RF power lead high fraction of monatomic ion beam. Here, Characteristics of helicon plasma sources are described. Design and its performances of a helicon ion source are presented

Development of an integrated, in-situ remediation technology: Task 2--4, electrokinetic modeling. Topical report, September 26--May 25, 1996

International Nuclear Information System (INIS)

1997-01-01

This report summarizes the work conducted in Tasks 2-4, which together make up the Electrokinetic Modeling carried out in this project. The modeling was divided into three main sections: thermal analysis, chemical species transport, and electrode geometry and soil heterogeneity issues. The thermal modeling consisted of development of the governing equations to incorporate Joule heating associated with electro-osmosis, heat conduction and convection, and temperature dependencies of electrical conductivity and electro-osmotic permeability. To model the transport of chemical species in the Lasagna TM process, a one-dimensional model was developed. This model is based on previous models, but includes additional mechanism to account for charge transfer in the double layer, pH buffering of the soil, and zeta potential dependency on pH and ionic strength. The results of this model and the corroboration by experimental measurement support some key assumptions made in the thermal model. An analysis was also conducted to compare the use of cylindrical electrodes to the plate geometry used in Phase I. In summary, cylindrical electrodes may be appropriate for anodes, because the do not intercept the flow. If used as cathodes, a planar treatment zone in their vicinity would probably be required. The cylindrical electrodes can operate at reasonable current densities without boiling water. Because the hottest region is at the electrode, cooling schemes could be used to operate at higher current densities. If iron anodes are used, they will have to be quite massive, and may not be economical compared to planar models. An example of soil heterogeneity was investigated when it was discovered that a steel pt was buried in the vicinity of the pilot test. There is some distortion of the field near the pit, but its effects on the test zone between the electrodes are minimal

New initiatives for producing high current electron accelerators

International Nuclear Information System (INIS)

Faehl, R.J.; Keinigs, R.K.; Pogue, E.W.

1996-01-01

New classes of compact electron accelerators able to deliver multi-kiloamperes of pulsed 10-50 MeV electron beams are being studied. One class is based upon rf linac technology with dielectric-filled cavities. For materials with ε/ε o >>1, the greatly increased energy storage permits high current operation. The second type is a high energy injected betatron. Circulating current limits scale as Β 2 γ 3

Morphodynamics of supercritical high-density turbidity currents

NARCIS (Netherlands)

Cartigny, M.

2012-01-01

Seafloor and outcrop observations combined with numerical and physical experiments show that turbidity currents are likely 1) to be in a supercritical flow state and 2) to carry high sediment concentrations (being of high-density). The thesis starts with an experimental study of bedforms

Electrokinetic energy conversion efficiency of viscoelastic fluids in a polyelectrolyte-grafted nanochannel.

Science.gov (United States)

Jian, Yongjun; Li, Fengqin; Liu, Yongbo; Chang, Long; Liu, Quansheng; Yang, Liangui

2017-08-01

In order to conduct extensive investigation of energy harvesting capabilities of nanofluidic devices, we provide analytical solutions for streaming potential and electrokinetic energy conversion (EKEC) efficiency through taking the combined consequences of soft nanochannel, a rigid nanochannel whose surface is covered by charged polyelectrolyte layer, and viscoelastic rheology into account. The viscoelasticity of the fluid is considered by employing the Maxwell constitutive model when the forcing frequency of an oscillatory driving pressure flow matches with the inverse of the relaxation time scale of a typical viscoelastic fluid. We compare the streaming potential and EKEC efficiency with those of a rigid nanochannel, having zeta potential equal to the electrostatic potential at the solid-polyelectrolyte interface of the soft nanochannels. Within the present selected parameter ranges, it is shown that the different peaks of maximal streaming potential and EKEC efficiency for the rigid nanochannel are larger than those for the soft nanochannel when forcing frequencies of the driving pressure gradient are close to resonating frequencies. However, more enhanced streaming potential and EKEC efficiency for a soft nanochannel can be found in most of the regions away from these resonant frequencies. Moreover, the influence of several dimensionless parameters on EKEC efficiency is discussed in detail. Finally, within the given parametric regions, the maximum efficiency at some resonant frequency obtained in present analysis is about 25%. Copyright © 2017 Elsevier B.V. All rights reserved.

Enhanced electrokinetic properties and antimicrobial activities of biodegradable chitosan/organo-bentonite composites.

Science.gov (United States)

Cabuk, Mehmet; Alan, Yusuf; Unal, H Ibrahim

2017-04-01

In this study, chitosan (CS), Na + -bentonite (Na + -BNT) and chitosan/organo-bentonite (CS/O-BNT) biodegradable composites having three different compositions were investigated. Electrokinetic measurements were examined in aqueous medium by taking the effects pH, electrolytes (NaCl and BaCl 2 ), surfactants (CTAB and SDS), and temperature into account. It was noticed that the initial ζ-potential of Na + -BNT shifted from negative (ζ=-35mV) to positive region (ζ=+13mV) with increasing polycationic CS content in the composite structure as aimed. Divalent 2:1 electrolyte (BaCl 2 ) caused to shift the ζ-potentials of all the dispersions to more positive regions. While the most negative effect on ζ-potential of the composites was reached with SDS, which reduced the value of ζ-potential to -39mV for CS(1)/O-BNT composite, the most positive effect was monitored with CTAB (ζ=+40mV) for CS(3)/O-BNT composite. Further, the composites were tested against various bacterial (Gram-positive and Gram-negative) and fungal microorganisms at various concentrations and results obtained were compared with the reference antibiotics and fungicide. According to inhibition zone values accomplished, antibacterial and antifungal activities of the CS/O-BNT composites are increased with increasing CS content as proportional with their positive ζ-potential values. Copyright © 2017 Elsevier Ltd. All rights reserved.

Liquid metal current collectors for high-speed rotating machinery

International Nuclear Information System (INIS)

Carr, S.L.

1976-01-01

Recent interest in superconducting motors and generators has created a renewed interest in homopolar machinery. Homopolar machine designs have always been limited by the need for compact, high-current, low-voltage, sliding electrical curent collectors. Conventional graphite-based solid brushes are inadequate for use in homopolar machines. Liquid metals, under certain conditions of relative sliding velocities, electrical currents, and magnetic fields are known to be capable of performing well in homopolar machines. An effort to explore the capabilities and limits of a tongue-and-groove style current collector, utilizing sodium-potassium eutectic alloy (NaK) as the working fluid in high sliding speed operation is reported here. A double current collector generator model with a 14.5-cm maximum rotor diameter, 20,000 rpm rotational capability, and electrical current carrying ability was constructed and operated successfully at a peripheral velocity of 125 m/s. The limiting factor in these experiments was a high-speed fluid-flow instability resulting in the ejection of the working fluid from the operating portions of the collectors. The effects of collector size and geometry, working fluid (NaK or water), and cover gas pressure are reported. Hydrodynamic frictional torque-speed curves are given for the two fluids and for several geometries. Electrical resistances as a function of peripheral velocity at 60 amperes are reported, and the phenomenology of the high-speed fluid-flow instabilities is discussed. The possibility of long-term high-speed operation of current collectors of the tongue-and-groove type, along with experimental and theoretical hydrodynamic friction losses at high peripheral velocities, is considered

Design of high current injector for SPring-8

International Nuclear Information System (INIS)

Yoshikawa, H.; Nakamura, N.; Mizuno, A.; Suzuki, S.; Hori, T.; Yanagida, K.; Mashiko, K.; Yokomizo, H.

1992-01-01

The linac of SPring-8, large synchrotron radiation facility of Japan, has the option which is positron operation modes. The electron gun of this linac is designed on base of the optimization for a high current beam to get positrons as many as possible. But otherwise this linac should be used as an accurate electron beam generator for commissioning on the whole facility. This report shows differences of the beam specification between a high current beam and a low current beam. The bunching section of this linac has just been constructed this summer at Tokai-Lab. of JAERI to be confirmed with the specification. (author). 3 refs., 1 tab., 4 figs

Electrokinetic and Hemostatic Profiles of Nonwoven Cellulosic/Synthetic Fiber Blends with Unbleached Cotton

Directory of Open Access Journals (Sweden)

J. Vincent Edwards

2014-11-01

Full Text Available Greige cotton contains waxes and pectin on the outer surface of the fiber that are removed when bleached, but these components present potential wound dressing functionality. Cotton nonwovens blended with hydrophobic and hydrophilic fibers including viscose, polyester, and polypropylene were assessed for clotting activity with thromboelastography (TEG and thrombin production. Clotting was evaluated based on TEG measurements: R (time to initiation of clot formation, K (time from end of R to a 20 mm clot, α (rate of clot formation according to the angle tangent to the curve as K is reached, and MA (clot strength. TEG values correlate to material surface polarity as measured with electrokinetic parameters (ζplateau, Δζ and swell ratio. The material surface polarity (ζplateau varied from −22 to −61 mV. K values and thrombin concentrations were found to be inversely proportional to  ζplateau with an increase in material hydrophobicity. An increase in the swell ratios of the materials correlated with decreased K values suggesting that clotting rates following fibrin formation increase with increasing material surface area due to swelling. Clot strength (MA also increased with material hydrophobicity. Structure/function implications from the observed clotting physiology induced by the materials are discussed.

Development of high current electron beam generator

Energy Technology Data Exchange (ETDEWEB)

Lee, Byeong Cheol; Lee, Jong Min; Kim, Sun Kook [and others

1997-05-01

A high-current electron beam generator has been developed. The energy and the average current of the electron beam are 2 MeV and 50 mA, respectively. The electron beam generator is composed of an electron gun, RF acceleration cavities, a 260-kW RF generator, electron beam optics components, and control system, etc. The electron beam generator will be used for the development of a millimeter-wave free-electron laser and a high average power infrared free-electron laser. The machine will also be used as a user facility in nuclear industry, environment industry, semiconductor industry, chemical industry, etc. (author). 15 tabs., 85 figs.

Development of high current electron beam generator

International Nuclear Information System (INIS)

Lee, Byeong Cheol; Lee, Jong Min; Kim, Sun Kook

1997-05-01

A high-current electron beam generator has been developed. The energy and the average current of the electron beam are 2 MeV and 50 mA, respectively. The electron beam generator is composed of an electron gun, RF acceleration cavities, a 260-kW RF generator, electron beam optics components, and control system, etc. The electron beam generator will be used for the development of a millimeter-wave free-electron laser and a high average power infrared free-electron laser. The machine will also be used as a user facility in nuclear industry, environment industry, semiconductor industry, chemical industry, etc. (author). 15 tabs., 85 figs

High-current proton accelerators-meson factories

International Nuclear Information System (INIS)

Dmitrievskij, V.P.

1979-01-01

A possibility of usage of accelerators of neutron as well as meson factories is considered. Parameters of linear and cyclic accelerators are given, which are employed as meson factories and as base for developing intense neutron generators. It is emphasized that the principal aim of developing neutron generators on the base of high current proton accelerators is production of intense neutron fluxes with a present energy spectrum. Production of tens-and-hundreds milliampere currents at the energy of 800-1000 MeV is considered at present for two types of accelerating facilities viz. linear accelerators under continuous operating conditions and cyclotrons with strong focusing. Quantitative evaluations of developing high-efficiency linear and cyclic accelerators are considered. The basic parameters of an ccelerating complex are given, viz. linear accelerator-injector and 800 MeV isochronous cyclotron. The main problems associated with their realization are listed [ru

Electroremediation of lead and vanadium of industrial residues; Remediacao eletrocinetica de chumbo e vanadio em residuos industriais

Energy Technology Data Exchange (ETDEWEB)

Abramchuk, Danusa; Iryoda, Kathia Izumi; Pedrazzoli, Carina [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept. de Engenharia Quimica; Ponte, Haroldo de Araujo; Ponte, Maria Jose de Jeronimo [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil)

2004-07-01

Every year many areas were polluted with heavy metals and other dangerous materials, causing enormous impacts in the quality of rivers and soils. The soil remediation techniques 'in situ' were efficient for the removal of heavy metals, as the electrokinetic recovery: an up-to-date technology that has attracting the interest of many researchers and government since the decade of 90. The electrokinetic remediation technique is based on application of a low intensity continuous current through the soil among two or more electrodes. The current mobilizes electric charged species, particles and ions in the soil by the following processes: electromigration, electro osmotic and electrolysis. The purpose is the evaluation of the electrokinetic technique application for the lead and vanadium remediation from solid wastes. Profiles of pH and concentration and their variation in time throughout an electrokinetical reactor were investigated in a system submitted to a constant electric field. The profiles of pH indicated great alkalinization in the cathodic region and acidification in the anodic one. As a consequence, there was a precipitation process of the metallic ions that have migrated to this region. This process favors the removal of metallic ions by pumping. (author)

Record high-average current from a high-brightness photoinjector

Energy Technology Data Exchange (ETDEWEB)

Dunham, Bruce; Barley, John; Bartnik, Adam; Bazarov, Ivan; Cultrera, Luca; Dobbins, John; Hoffstaetter, Georg; Johnson, Brent; Kaplan, Roger; Karkare, Siddharth; Kostroun, Vaclav; Li Yulin; Liepe, Matthias; Liu Xianghong; Loehl, Florian; Maxson, Jared; Quigley, Peter; Reilly, John; Rice, David; Sabol, Daniel [Cornell Laboratory for Accelerator-Based Sciences and Education, Cornell University, Ithaca, New York 14853 (United States); and others

2013-01-21

High-power, high-brightness electron beams are of interest for many applications, especially as drivers for free electron lasers and energy recovery linac light sources. For these particular applications, photoemission injectors are used in most cases, and the initial beam brightness from the injector sets a limit on the quality of the light generated at the end of the accelerator. At Cornell University, we have built such a high-power injector using a DC photoemission gun followed by a superconducting accelerating module. Recent results will be presented demonstrating record setting performance up to 65 mA average current with beam energies of 4-5 MeV.

Proposal for a race-track microtron with high peak current

NARCIS (Netherlands)

Ernst, G.J.; Haselhoff, E.H.; Witteman, W.J.; Botman, J.I.M.; van Genderen, W.; Hagedoorn, H.L.; van der Heide, J.A.; Kleeven, W.J.G.M.

1989-01-01

In order to obtain high gain in a free electron laser a high-quality electron beam with high peak current is required. It is well-known that a microtron is able to produce a high-quality beam having low emittance and small energy spread (1%). Because a circular microtron has a limited high-current

Research on high beam-current accelerators

International Nuclear Information System (INIS)

Keefe, D.

1981-01-01

In this review of research being undertaken at present in the US on accelerating devices and concepts of a novel nature, both non-collective systems, including high-current rf linacs and a variety of induction linacs, and also collective systems are considered. (U.K.)

High current ion source development at Frankfurt

Energy Technology Data Exchange (ETDEWEB)

Volk, K.; Klein, H.; Lakatos, A.; Maaser, A.; Weber, M. [Frankfurt Univ. (Germany). Inst. fuer Angewandte Physik

1995-11-01

The development of high current positive and negative ion sources is an essential issue for the next generation of high current linear accelerators. Especially, the design of the European Spallation Source facility (ESS) and the International Fusion Material Irradiation Test Facility (IFMIF) have increased the significance of high brightness hydrogen and deuterium sources. As an example, for the ESS facility, two H{sup -}-sources each delivering a 70 mA H{sup -}-beam in 1.45 ms pulses at a repetition rate of 50 Hz are necessary. A low emittance is another important prerequisite. The source must operate, while meeting the performance requirements, with a constancy and reliability over an acceptable period of time. The present paper summarizes the progress achieved in ion sources development of intense, single charge, positive and negative ion beams. (author) 16 figs., 7 refs.

High current ion source development at Frankfurt

International Nuclear Information System (INIS)

Volk, K.; Klein, H.; Lakatos, A.; Maaser, A.; Weber, M.

1995-01-01

The development of high current positive and negative ion sources is an essential issue for the next generation of high current linear accelerators. Especially, the design of the European Spallation Source facility (ESS) and the International Fusion Material Irradiation Test Facility (IFMIF) have increased the significance of high brightness hydrogen and deuterium sources. As an example, for the ESS facility, two H - -sources each delivering a 70 mA H - -beam in 1.45 ms pulses at a repetition rate of 50 Hz are necessary. A low emittance is another important prerequisite. The source must operate, while meeting the performance requirements, with a constancy and reliability over an acceptable period of time. The present paper summarizes the progress achieved in ion sources development of intense, single charge, positive and negative ion beams. (author) 16 figs., 7 refs

Binary electrokinetic separation of target DNA from background DNA primers.

Energy Technology Data Exchange (ETDEWEB)

James, Conrad D.; Derzon, Mark Steven

2005-10-01

This report contains the summary of LDRD project 91312, titled ''Binary Electrokinetic Separation of Target DNA from Background DNA Primers''. This work is the first product of a collaboration with Columbia University and the Northeast BioDefense Center of Excellence. In conjunction with Ian Lipkin's lab, we are developing a technique to reduce false positive events, due to the detection of unhybridized reporter molecules, in a sensitive and multiplexed detection scheme for nucleic acids developed by the Lipkin lab. This is the most significant problem in the operation of their capability. As they are developing the tools for rapidly detecting the entire panel of hemorrhagic fevers this technology will immediately serve an important national need. The goal of this work was to attempt to separate nucleic acid from a preprocessed sample. We demonstrated the preconcentration of kilobase-pair length double-stranded DNA targets, and observed little preconcentration of 60 base-pair length single-stranded DNA probes. These objectives were accomplished in microdevice formats that are compatible with larger detection systems for sample pre-processing. Combined with Columbia's expertise, this technology would enable a unique, fast, and potentially compact method for detecting/identifying genetically-modified organisms and multiplexed rapid nucleic acid identification. Another competing approach is the DARPA funded IRIS Pharmaceutical TIGER platform which requires many hours for operation, and an 800k$ piece of equipment that fills a room. The Columbia/SNL system could provide a result in 30 minutes, at the cost of a few thousand dollars for the platform, and would be the size of a shoebox or smaller.

High pressure, high current, low inductance, high reliability sealed terminals

Science.gov (United States)

Hsu, John S [Oak Ridge, TN; McKeever, John W [Oak Ridge, TN

2010-03-23

The invention is a terminal assembly having a casing with at least one delivery tapered-cone conductor and at least one return tapered-cone conductor routed there-through. The delivery and return tapered-cone conductors are electrically isolated from each other and positioned in the annuluses of ordered concentric cones at an off-normal angle. The tapered cone conductor service can be AC phase conductors and DC link conductors. The center core has at least one service conduit of gate signal leads, diagnostic signal wires, and refrigerant tubing routed there-through. A seal material is in direct contact with the casing inner surface, the tapered-cone conductors, and the service conduits thereby hermetically filling the interstitial space in the casing interior core and center core. The assembly provides simultaneous high-current, high-pressure, low-inductance, and high-reliability service.

HIGH-CURRENT ERL-BASED ELECTRON COOLING FOR RHIC

International Nuclear Information System (INIS)

BEN-ZVI, I.

2005-01-01

The design of an electron cooler must take into account both electron beam dynamics issues as well as the electron cooling physics. Research towards high-energy electron cooling of RHIC is in its 3rd year at Brookhaven National Laboratory. The luminosity upgrade of RHIC calls for electron cooling of various stored ion beams, such as 100 GeV/A gold ions at collision energies. The necessary electron energy of 54 MeV is clearly out of reach for DC accelerator system of any kind. The high energy also necessitates a bunched beam, with a high electron bunch charge, low emittance and small energy spread. The Collider-Accelerator Department adopted the Energy Recovery Linac (ERL) for generating the high-current, high-energy and high-quality electron beam. The RHIC electron cooler ERL will use four Superconducting RF (SRF) 5-cell cavities, designed to operate at ampere-class average currents with high bunch charges. The electron source will be a superconducting, 705.75 MHz laser-photocathode RF gun, followed up by a superconducting Energy Recovery Linac (ERL). An R and D ERL is under construction to demonstrate the ERL at the unprecedented average current of 0.5 amperes. Beam dynamics performance and luminosity enhancement are described for the case of magnetized and non-magnetized electron cooling of RHIC

High current density magnets for INTOR and TIBER

International Nuclear Information System (INIS)

Miller, J.R.; Henning, C.D.; Kerns, J.A.; Slack, D.S.; Summers, L.T.; Zbasnik, J.P.

1986-12-01

The adoption of high current density, high field, superconducting magnets for INTOR and TIBER would prove beneficial. When combined with improved radiation tolerance of the magnets to minimize the inner leg shielding, a substantial reduction in machine dimensions and capital costs can be achieved. Fortunately, cable-in-conduit conductors (CICC) which are capable of the desired enhancements are being developed. Because conductor stability in a CICC depends more on the trapped helium enthalpy, rather than the copper resistivity, higher current densities of the order of 40 A/mm 2 at 12 T are possible. Radiation damage to the copper stabilizer is less important because the growth in resistance is a second-order effect on stability. Such CICC conductors lend themselves naturally to niobium-tin utilization, with the benefits of the high current-sharing temperature of this material being taken to advantage in absorbing radiation heating. When the helium coolant is injected at near the critical pressure, Joule-Thompson expansion in the flow path tends to stabilize the fluid temperature at under 6 K. Thus, higher fields, as well as higher current densities, can be considered for INTOR or TIBER

Current sharing effect on the current instability and allowable temperature rise of composite high-TC superconductors

International Nuclear Information System (INIS)

Romanovskii, V.R.; Watanabe, K.; Awaji, S.; Nishijima, G.; Takahashi, Ken-ichiro

2004-01-01

To understand the basic mechanisms of the thermal runaway phenomenon, the limiting margin of the current instability, which may spontaneously occur in composite high-T C superconductors like multifilament Bi-based wire or tape, is derived under DC magnetic field. The current sharing and allowable temperature rise effects were considered. A static zero-dimensional model was utilized to describe the basic formulae dealing with the peculiarities of the non-isothermal change of superconducting composite voltage-current characteristic. The boundary of allowable stable values of the temperature, electric field and current are derived analytically. It was shown that permissible values of the current and electric field might be higher than those determined by use of the standard critical current criterion. In consequence of this feature, the noticeable allowable temperature rise of the composite superconductor before its transition to the normal state may be seen. The criterion for complete thermal stability condition is written describing the state when temperature of the composite equals critical temperature of a superconductor and the transport current flows stably only in matrix. The performed analysis also proves the existence of value of the volume fraction of a superconductor in composite at which its current-carrying capacity has minimum. These peculiarities are due to the stable current redistribution between superconductor and stabilizing matrix. Therefore, the current sharing not only leads to the matrix/superconductor ratio effect on the stable operating characteristics of the composite high-T C superconductors but also becomes important in the adequate description of quench process in the high-T C superconducting magnets

Computation of stationary 3D halo currents in fusion devices with accuracy control

Science.gov (United States)

Bettini, Paolo; Specogna, Ruben

2014-09-01

This paper addresses the calculation of the resistive distribution of halo currents in three-dimensional structures of large magnetic confinement fusion machines. A Neumann electrokinetic problem is solved on a geometry so complicated that complementarity is used to monitor the discretization error. An irrotational electric field is obtained by a geometric formulation based on the electric scalar potential, whereas three geometric formulations are compared to obtain a solenoidal current density: a formulation based on the electric vector potential and two geometric formulations inspired from mixed and mixed-hybrid Finite Elements. The electric vector potential formulation is usually considered impractical since an enormous computing power is wasted by the topological pre-processing it requires. To solve this challenging problem, we present novel algorithms based on lazy cohomology generators that enable to save orders of magnitude computational time with respect to all other state-of-the-art solutions proposed in literature. Believing that our results are useful in other fields of scientific computing, the proposed algorithm is presented as a detailed pseudocode in such a way that it can be easily implemented.

Preparation and characterization of high-Tc superconducting thin films with high critical current densities

International Nuclear Information System (INIS)

Vase, P.

1991-08-01

The project was carried out in relation to possible cable and electronics applications of high-T c materials. Laser ablation was used as the deposition technique because of its stoichiometry conservation. Films were made in the YBa 2 Cu 3 O 7 compound due to its relatively simple stoichiometry compared to other High-T c compounds. Much attention was paid to the critical current density. A very high critical current density was reached. By using texture analysis by X-ray diffraction, it was found that films with high critical current densities were epitaxial, while films with low critical current densities contained several crystalline orientations. Four techniques for patterning the films were used - photo lithography and wet etch, laser ablation lithography, laser writing and electron beam lithography and ion milling. Sub-micron patterning has been demonstrated without degradation of the superconducting properties. The achieved patterning resolution is sufficient for preparation of many superconducting components. (AB)

Development of a high brightness, high current SRF photo-electron source for ERL applications

Energy Technology Data Exchange (ETDEWEB)

Neumann, Axel [Helmholtz-Zentrum Berlin (Germany); Collaboration: bERLinPro Team

2016-07-01

Energy recovery linacs (ERL) offer the potential to combine major beam properties of the two main domains of particle accelerators: The low emittance of linear accelerators and the high average beam current of storage rings, while also allowing to compress to short bunches below the ps regime. This makes among other applications ERLs an ideal candidate for future light sources. The beam properties of the ERL are given by the performance of the injection section and hence of the beam source. Helmholtz-Zentrum Berlin is currently designing and building a high average current all superconducting CW driven ERL as a prototype to demonstrate low normalized beam emittance of 1 mm*mrad at 100 mA and short pulses of about 2 ps. In this contribution we discuss the development of this class of a high brightness, high current SRF photo-electron source and present recent commissioning results. Also, alternative approaches at other laboratories are shortly reviewed.

A high current density DC magnetohydrodynamic (MHD) micropump

NARCIS (Netherlands)

Homsy, Alexandra; Koster, Sander; Hogen-Koster, S.; Eijkel, Jan C.T.; van den Berg, Albert; Lucklum, F.; Verpoorte, E.; de Rooij, Nico F.

2005-01-01

This paper describes the working principle of a DC magnetohydrodynamic (MHD) micropump that can be operated at high DC current densities (J) in 75-µm-deep microfluidic channels without introducing gas bubbles into the pumping channel. The main design feature for current generation is a micromachined

A high current density DC magnetohydrodynamic (MHD) micropump

NARCIS (Netherlands)

Homsy, A; Koster, Sander; Eijkel, JCT; van den Berg, A; Lucklum, F; Verpoorte, E; de Rooij, NF

2005-01-01

This paper describes the working principle of a DC magnetohydrodynamic (MHD) micropump that can be operated at high DC current densities (J) in 75-mu m-deep microfluidic channels without introducing gas bubbles into the pumping channel. The main design feature for current generation is a

Determination of strobilurin fungicide residues in fruits and vegetables by micellar electrokinetic capillary chromatography with sweeping.

Science.gov (United States)

Wang, Kun; Chen, Guan-hua; Wu, Xian; Shi, Jie; Guo, Dong-shan

2014-02-01

A new assay of micellar electrokinetic capillary chromatography with sweeping was developed to determine azoxystrobin, kresoxim-methyl and pyraclostrobin in fruits and vegetables. The key factors affecting resolution and peak height were studied and the optimum conditions were obtained for separation and enrichment. The running buffer consisted of 40 mM borate, 25 mM sodium dodecyl sulfate and 15% acetonitrile, and its pH was adjusted to 8.4. The sample was injected for 677 nL and the separation voltage was 25 kV. Under the optimum conditions, the enrichment factors of azoxystrobin, kresoxim-methyl and pyraclostrobin were 861, 550 and 403; the linear dynamic ranges were all 0.01-5.0 mg/L; the limits of detection were 0.002, 0.001 and 0.002 mg/kg; the recoveries of spiked samples were 85.1-98.5%, 87.5-97.0% and 89.1-99.1%, respectively. The assay can meet the requirement of maximum residue limits for these three strobilurin fungicides, and has been applied for determining their residues in fruits and vegetables.

The design of a five-cell high-current superconducting cavity

International Nuclear Information System (INIS)

Li Yongming; Zhu Feng; Quan Shengwen; Liu Kexin; Nassiri, Ali

2012-01-01

Energy recovery linacs are promising for achieving high average current with superior beam quality. The key component for accelerating such high-current beams is the superconducting radio-frequency cavity. The design of a 1.3 GHz five-cell high-current superconducting cavity has been carried out under cooperation between Peking University and the Argonne National Laboratory. The radio-frequency properties, damping of the higher order modes, multipacting and mechanical features of this cavity have been discussed and the final design is presented. (authors)

Surface study of stainless steel electrode deposition from soil electrokinetic (EK) treatment using X-ray photoelectron spectroscopy (XPS)

Energy Technology Data Exchange (ETDEWEB)

Embong, Zaidi, E-mail: zaidi@uthm.edu.my [Faculty of Science, Technology and Human Development, Universiti Tun Hussien Onn Malaysia (UTHM) 86400, Parit Raja, Batu, Johor (Malaysia); Research Centre for Soft Soils (RECESS), Office for Research, Innovation, Commercialization and Consultancy Management (ORICC), Universiti Tun Hussien Onn Malaysia UTHM 86400, Parit Raja, Batu, Johor (Malaysia); Johar, Saffuwan [Faculty of Science, Technology and Human Development, Universiti Tun Hussien Onn Malaysia (UTHM) 86400, Parit Raja, Batu, Johor (Malaysia); Tajudin, Saiful Azhar Ahmad [Research Centre for Soft Soils (RECESS), Office for Research, Innovation, Commercialization and Consultancy Management (ORICC), Universiti Tun Hussien Onn Malaysia UTHM 86400, Parit Raja, Batu, Johor (Malaysia); Sahdan, Mohd Zainizan [Microelectronics and Nanotechnology Centre (MiNT-SRC), Office for Research, Innovation, Commercialization and Consultancy Management (ORICC), Universiti Tun Hussien Onn Malaysia UTHM 86400, Parit Raja, Batu, Johor (Malaysia)

2015-04-29

Electrokinetic (EK) remediation relies upon application of a low-intensity direct current through the soil between stainless steel electrodes that are divided into a cathode array and an anode array. This mobilizes charged species, causing ions and water to move toward the electrodes. Metal ions and positively charged organic compounds move toward the cathode. Anions such as chloride, fluoride, nitrate, and negatively charged organic compounds move toward the anode. Here, this remediation techniques lead to a formation of a deposition at the both cathode and anode surface that mainly contributed byanion and cation from the remediated soil. In this research, Renggam-Jerangau soil species (HaplicAcrisol + RhodicFerralsol) with a surveymeter reading of 38.0 ± 3.9 μR/hr has been investigation in order to study the mobility of the anion and cation under the influence electric field. Prior to the EK treatment, the elemental composition of the soil and the stainless steel electrode are measured using XRF analyses. Next, the soil sample is remediated at a constant electric potential of 30 V within an hour of treatment period. A surface study for the deposition layer of the cathode and anode using X-ray Photoelectron spectroscopy (XPS) revealed that a narrow photoelectron signal from oxygen O 1s, carbon, C 1s silica, Si 2p, aluminium, Al 2p and chromium, Cr 2p exhibited on the electrode surface and indicate that a different in photoelectron intensity for each element on both electrode surface. In this paper, the mechanism of Si{sup 2+} and Al{sup 2+} cation mobility under the influence of voltage potential between the cathode and anode will be discussed in detail.

Surface study of stainless steel electrode deposition from soil electrokinetic (EK) treatment using X-ray photoelectron spectroscopy (XPS)

International Nuclear Information System (INIS)

Embong, Zaidi; Johar, Saffuwan; Tajudin, Saiful Azhar Ahmad; Sahdan, Mohd Zainizan

2015-01-01

Electrokinetic (EK) remediation relies upon application of a low-intensity direct current through the soil between stainless steel electrodes that are divided into a cathode array and an anode array. This mobilizes charged species, causing ions and water to move toward the electrodes. Metal ions and positively charged organic compounds move toward the cathode. Anions such as chloride, fluoride, nitrate, and negatively charged organic compounds move toward the anode. Here, this remediation techniques lead to a formation of a deposition at the both cathode and anode surface that mainly contributed byanion and cation from the remediated soil. In this research, Renggam-Jerangau soil species (HaplicAcrisol + RhodicFerralsol) with a surveymeter reading of 38.0 ± 3.9 μR/hr has been investigation in order to study the mobility of the anion and cation under the influence electric field. Prior to the EK treatment, the elemental composition of the soil and the stainless steel electrode are measured using XRF analyses. Next, the soil sample is remediated at a constant electric potential of 30 V within an hour of treatment period. A surface study for the deposition layer of the cathode and anode using X-ray Photoelectron spectroscopy (XPS) revealed that a narrow photoelectron signal from oxygen O 1s, carbon, C 1s silica, Si 2p, aluminium, Al 2p and chromium, Cr 2p exhibited on the electrode surface and indicate that a different in photoelectron intensity for each element on both electrode surface. In this paper, the mechanism of Si 2+ and Al 2+ cation mobility under the influence of voltage potential between the cathode and anode will be discussed in detail

Design considerations for high-current superconducting ion linacs

International Nuclear Information System (INIS)

Delayen, J.R.; Bohn, C.L.; Micklich, B.J.; Roche, C.T.; Sagalovsky, L.

1993-01-01

Superconducting linacs may be a viable option for high-current applications such as fusion materials irradiation testing, spallation neutron source, transmutation of radioactive waste, tritium production, and energy production. These linacs must run reliably for many years and allow easy routine maintenance. Superconducting cavities operate efficiently with high cw gradients, properties which help to reduce operating and capital costs, respectively. However, cost-effectiveness is not the sole consideration in these applications. For example, beam impingement must be essentially eliminated to prevent unsafe radioactivation of the accelerating structures, and thus large apertures are needed through which to pass the beam. Because of their high efficiency, superconducting cavities can be designed with very large bore apertures, thereby reducing the effect of beam impingement. Key aspects of high-current cw superconducting linac designs are explored in this context

Transient analysis of carbon monoxide transport phenomena and adsorption kinetics in HT-PEMFC during dynamic current extraction

International Nuclear Information System (INIS)

Raj, Kamal Abdul Rasheedj; Chan, Siew Hwa

2015-01-01

Highlights: • Increasing the fuel cell temperature reduces outlet CO concentration. • Increasing the CO inlet (initial) concentration increases outlet CO concentration. • Increasing current density step and dwell time increases outlet CO concentration. • Increasing in the CL and GDL porosities reduces outlet CO concentration. - Abstract: This paper investigates the transport phenomena of carbon monoxide (CO) and adsorption kinetics, in a high-temperature proton exchange membrane fuel cell (HT-PEMFC) during step-wise current extraction (step-change in current extraction). Step-wise current extraction is a common process done to accommodate a sudden power surge during an operation. Since HT-PEMFCs are capable of handling high impurity of CO, hydrogen fuel that is contaminated with trace amount of CO is usually considered for commercial benefits. Thus, a transient three-dimensional isothermal anodic electro-kinetic numerical model is developed to determine the effect of operating parameters such as fuel cell temperature, CO inlet (initial) concentration, step-change of current density and dwell time on the transport phenomena of CO and adsorption kinetics. In addition, geometrical factors such as the catalyst layer (CL) and gas diffusion layer (GDL) porosity are also varied as well. The results show that the above-mentioned operating parameters can affect the maximum CO concentration at the CL, especially at the outlet of the channel. Specifically, a reduction of fuel cell temperature can significantly increase the CO concentration near the outlet, while increasing CO inlet (initial) concentration, step-change amplitude of current density and current density dwell time can cause an increase in CO concentration at the outlet, albeit to different extent. In addition, the increase in the porosity of CL and GDL, results in the reduction of the maximum CO concentration at the outlet, albeit to different extent. In addition, the CO and hydrogen surface coverage

High-temperature superconducting current leads

Science.gov (United States)

Hull, J. R.

1992-07-01

The use of high-temperature superconductors (HTSs) for current leads to deliver power to devices at liquid helium temperature is near commercial realization. The use of HTSs in this application has the potential to reduce refrigeration requirements and helium boiloff to values significantly lower than the theoretical best achievable with conventional leads. Considerable advantage is achieved by operating these leads with an intermediate temperature heat sink. The HTS part of the lead can be made from pressed and sintered powder. Powder-in-tube fabrication is also possible, however, the normal metal part of the lead acts as a thermal short and cannot provide much stabilization without increasing the refrigeration required. Lead stability favors designs with low current density. Such leads can be manufactured with today's technology, and lower refrigeration results from the same allowable burnout time. Higher current densities result in lower boiloff for the same lead length, but bumout times can be very short. In comparing experiment to theory, the density of helium vapor needs to be accounted for in calculating the expected boiloff. For very low-loss leads, two-dimensional heat transfer and the state of the dewar near the leads may play a dominant role in lead performance.

High-current pulses from inductive energy stores

International Nuclear Information System (INIS)

Wipf, S.L.

1981-01-01

Superconducting inductive energy stores can be used for high power pulse supplies if a suitable current multiplication scheme is used. The concept of an inductive Marx generator is superior to a transformer. A third scheme, a variable flux linkage device, is suggested; in multiplying current it also compresses energy. Its function is in many ways analogous to that of a horsewhip. Superconductor limits indicate that peak power levels of TW can be reached for stored energies above 1 MJ

Mechanism of streaming current generation by concentration gradients in packed-particle columns

Czech Academy of Sciences Publication Activity Database

Vespalec, Radim; van Leeuwen, H. P.

2001-01-01

Roč. 244, č. 1 (2001), s. 66-73 ISSN 0021-9797 R&D Projects: GA AV ČR IAA4031703; GA ČR GA203/99/0044 Institutional research plan: CEZ:AV0Z4031919 Keywords : electrokinetics * electric double layer * electrochromatography Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.530, year: 2001

In-situ treatment of PCP contaminated soil by electrokinetics-Fenton-biodegradation process

Energy Technology Data Exchange (ETDEWEB)

Yang, G.C.C.; Chen Jenteh [Inst. of Environmental Engineering, National Sun Yat-Sen Univ., Kaohsiung (Taiwan)

2001-07-01

This laboratory investigation was conducted to evaluate the treatment efficiency of a process combining electrokinetic remediation (EK), Fenton process, and biodegradation for treating a pentachlorophenol (PCP) contaminated soil. For EK-Fenton experiments, the results have indicated that an increase of treatment time (e.g., from 10 to 15 days) would substantially increase the overall treatment (i.e., removal and destruction) efficiency of PCP. Only a limited increase of the treatment efficiency would be found if the concentration of FeSO{sub 4} was increased from 0.0196M to 0.098M. When scrap iron power was employed as the catalyst, the residual PCP concentration for soil near the anode end was found to be lower than that of 0.0196M FeSO{sub 4}. But its overall treatment efficiency was only 56.58%, which is lower than 68.34% obtained by using 0.0196M FeSO{sub 4} and 0.35% H{sub 2}O{sub 2}. When H{sub 2}O{sub 2} concentration was further increased to 3.5%, an overall treatment efficiency of 79.77% would be obtained when 0.0196M FeSO{sub 4} was used. When treated by EK-biodegradation process with phenol enrichment bacteria, the overall treatment efficiency of PCP was as low as 25.67%. If PCP contaminated soil was pre-treated by EK-Fenton process and followed by EK-biodegradation, an overall treatment efficiency of 100% was found to be achievable. (orig.)

High current betatron research at the University of New Mexico

International Nuclear Information System (INIS)

Humphries, S. Jr.; Len, L.K.

1987-01-01

Betatrons are among the simplest of high energy accelerators. Their circuit is equivalent to a step-up transformer; the electron beam forms a multi-turn secondary winding. Circulation of the beam around the flux core allows generation of high energy electrons with relatively small core mass. As with any transformer, a betatron is energy inefficient at low beam current; the energy balance is dominated by core losses. This fact has prompted a continuing investigation of high current betatrons as efficient, compact sources of beta and gamma radiation. A program has been supported at the University of New Mexico by the Office of Naval Research to study the physics of high current electron beams in circular accelerators and to develop practical technology for high power betatrons. Fabrication and assembly of the main ring was completed in January of this year. In contrast to other recent high current betatron experiments the UNM device utilizes a periodic focusing system to contain high current beams during the low energy phase of the acceleration cycle. The reversing cusp fields generated by alternating polarity solenoidal lenses cancel beam drift motions induced by machine errors. In consequence, they have found that the cusp geometry has had significantly better stability properties than a monodirectional toroidal field. In comparison to other minimum-Β geometries such as the Stelllatron cusps have open field lines which facilitate beam injection and neutralization

Field-Amplified Sample Injection-Micellar Electrokinetic Chromatography for the Determination of Benzophenones in Food Simulants

Directory of Open Access Journals (Sweden)

Cristina Félez

2015-07-01

Full Text Available A field-amplified sample injection-micellar electrokinetic chromatography (FASI-MEKC method for the determination of 14 benzophenones (BPs in a food simulant used in migration studies of food packaging materials was developed, allowing almost baseline separation in less than 21 min. The use of a 10 mM sodium dodecyl sulfate (SDS solution as sample matrix was mandatory to achieve FASI enhancement of the analyzed BPs. A 21- to 784-fold sensitivity enhancement was achieved with FASI-MEKC, obtaining limits of detection down to 5.1–68.4 µg/L, with acceptable run-to-run precisions (RSD values lower than 22.3% and accuracy (relative errors lower than 21.0%. Method performance was evaluated by quantifying BPs in the food simulant spiked at 500 µg/L (bellow the established specific migration limit for BP (600 µg/L by EU legislation. For a 95% confidence level, no statistical differences were observed between found and spiked concentrations (probability at the confidence level, p value, of 0.55, showing that the proposed FASI-MEKC method is suitable for the analysis of BPs in food packaging migration studies at the levels established by EU legislation.

Fast-response protection from high currents

International Nuclear Information System (INIS)

Novikov, A.A.

1989-01-01

Protection devices for power electronic equipment from shorting current are described. The device is shunted using spark gaps with minimal possible number of spark gaps to protect it. High fast-response (<100 ns) and operation voltage wide range (6-100 kV) are attained using Arkadiev-Marx generator-base trigger devices and air-core pulse transformer

Simple micellar electrokinetic chromatography method for the determination of hydrogen sulfide in hen tissues.

Science.gov (United States)

Kubalczyk, Paweł; Borowczyk, Kamila; Chwatko, Grażyna; Głowacki, Rafał

2015-04-01

A new method for the determination of hydrogen sulfide in hen tissues has been developed and validated. For estimation of hydrogen sulfide content, a sample (0.1 g) of hen tissue was treated according to the procedure consisted of some essential steps: simultaneous homogenization of a tissue and derivatization of hydrogen sulfide to its S-quinolinium derivative with 2-chloro-1-methylquinolinium tetrafluoroborate, separation of so-formed derivative by micellar electrokinetic chromatography with sweeping, and detection and quantitation with the use of UV detector set to measure analytical signals at 375 nm. Effective electrophoretic separation was achieved using fused silica capillary (effective length 41.5 cm, 75 μm id) and 0.05 mol/L, pH 8 phosphate buffer with the addition of 0.04 mol/L SDS and 26% ACN. The lower limit of quantification was 0.12 μmol hydrogen sulfide in 1 g of tissue. The calibration curve prepared in tissue homogenate for hydrogen sulfide showed linearity in the range from 0.15 to 2.0 μmol/g, with the coefficient of correlation 0.9978. The relative standard deviation of the points of the calibration curve varied from 8.3 to 3.2% RSD. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Double disordered YBCO coated conductors of industrial scale: high currents in high magnetic field

International Nuclear Information System (INIS)

Abraimov, D; Francis, A; Jaroszynski, J; McCallister, J; Polyanskii, A; Santos, M; Viouchkov, Y L; Ballarino, A; Bottura, L; Rossi, L; Barth, C; Senatore, C; Dietrich, R; Rutt, A; Schlenga, K; Usoskin, A; Majkic, G S; Selvamanickam, V

2015-01-01

A significant increase of critical current in high magnetic field, up to 31 T, was recorded in long tapes manufactured by employing a double-disorder route. In a double-disordered high-temperature superconductor (HTS), a superimposing of intrinsic and extrinsic disorder takes place in a way that (i) the intrinsic disorder is caused by local stoichiometry deviations that lead to defects of crystallinity that serve as pining centers in the YBa 2 Cu 3 O x−δ matrix and (ii) the extrinsic disorder is introduced via embedded atoms or particles of foreign material (e.g. barium zirconate), which create a set of lattice defects. We analyzed possible technological reasons for this current gain. The properties of these tapes over a wider field-temperature range as well as field anisotropy were also studied. Record values of critical current as high as 309 A at 31 T, 500 A at 18 Tm and 1200 A at 5 T were found in 4 mm wide tape at 4.2 K and B perpendicular to tape surface. HTS layers were processed in medium-scale equipment that allows a maximum batch length of 250 m while 22 m long batches were provided for investigation. Abnormally high ratios (up to 10) of critical current density measured at 4.2 K, 19 T to critical current density measured at 77 K, self-field were observed in tapes with the highest in-field critical current. Anisotropy of the critical current as well as angular dependences of n and α values were investigated. The temperature dependence of critical current is presented for temperatures between 4.2 and 40 K. Prospects for the suppression of the dog-bone effect by Cu plating and upscale of processing chain to >500 m piece length are discussed. (paper)

Double disordered YBCO coated conductors of industrial scale: high currents in high magnetic field

Science.gov (United States)

Abraimov, D.; Ballarino, A.; Barth, C.; Bottura, L.; Dietrich, R.; Francis, A.; Jaroszynski, J.; Majkic, G. S.; McCallister, J.; Polyanskii, A.; Rossi, L.; Rutt, A.; Santos, M.; Schlenga, K.; Selvamanickam, V.; Senatore, C.; Usoskin, A.; Viouchkov, Y. L.

2015-11-01

A significant increase of critical current in high magnetic field, up to 31 T, was recorded in long tapes manufactured by employing a double-disorder route. In a double-disordered high-temperature superconductor (HTS), a superimposing of intrinsic and extrinsic disorder takes place in a way that (i) the intrinsic disorder is caused by local stoichiometry deviations that lead to defects of crystallinity that serve as pining centers in the YBa2Cu3O x-δ matrix and (ii) the extrinsic disorder is introduced via embedded atoms or particles of foreign material (e.g. barium zirconate), which create a set of lattice defects. We analyzed possible technological reasons for this current gain. The properties of these tapes over a wider field-temperature range as well as field anisotropy were also studied. Record values of critical current as high as 309 A at 31 T, 500 A at 18 Tm and 1200 A at 5 T were found in 4 mm wide tape at 4.2 K and B perpendicular to tape surface. HTS layers were processed in medium-scale equipment that allows a maximum batch length of 250 m while 22 m long batches were provided for investigation. Abnormally high ratios (up to 10) of critical current density measured at 4.2 K, 19 T to critical current density measured at 77 K, self-field were observed in tapes with the highest in-field critical current. Anisotropy of the critical current as well as angular dependences of n and α values were investigated. The temperature dependence of critical current is presented for temperatures between 4.2 and 40 K. Prospects for the suppression of the dog-bone effect by Cu plating and upscale of processing chain to >500 m piece length are discussed.

Monitoring of interaction of low-frequency electric field with biological tissues upon optical clearing with optical coherence tomography.

Science.gov (United States)

Peña, Adrián F; Doronin, Alexander; Tuchin, Valery V; Meglinski, Igor

2014-08-01

The influence of a low-frequency electric field applied to soft biological tissues ex vivo at normal conditions and upon the topical application of optical clearing agents has been studied by optical coherence tomography (OCT). The electro-kinetic response of tissues has been observed and quantitatively evaluated by the double correlation OCT approach, utilizing consistent application of an adaptive Wiener filtering and Fourier domain correlation algorithm. The results show that fluctuations, induced by the electric field within the biological tissues are exponentially increased in time. We demonstrate that in comparison to impedance measurements and the mapping of the temperature profile at the surface of the tissue samples, the double correlation OCT approach is much more sensitive to the changes associated with the tissues' electro-kinetic response. We also found that topical application of the optical clearing agent reduces the tissues' electro-kinetic response and is cooling the tissue, thus reducing the temperature induced by the electric current by a few degrees. We anticipate that dcOCT approach can find a new application in bioelectrical impedance analysis and monitoring of the electric properties of biological tissues, including the resistivity of high water content tissues and its variations.

Elemental composition study of heavy metal (Ni, Cu, Zn) in riverbank soil by electrokinetic-assisted phyto remediation using XRF and SEM/EDX

International Nuclear Information System (INIS)

Suhailly Jamari; Zaidi Embong; Zaidi Embong; Ismail Bakar

2013-01-01

Full-text: Electrokinetic (EK)-assisted phyto remediation is one of the methods that have a big potential in enhancing the ability of plant uptake in soils remediation process. This research was conducted to investigate the difference in elemental composition concentration of riverbank soil and the change of pH between pre- and post-phyto remediation under the following condition: 1) control or as-receive sample; 2) Dieffenbachia spp plant with EK system (a pair of EK electrodes connected to a direct current (DC) power supply). After the electrodes were connected to a magnitude of 6 V/ cm -1 electric field for 4 hours/ day, the soil and plant samples were analyzed using and X-ray Fluorescence Spectrometer (XRF) and Scanning Electron Microscope/ Energy Dispersive X-ray Spectroscopy (SEM/ EDX). The SEM/EDX analysis showed that concentration of elemental composition (Ni, Cu and Zn) in post-phyto remediation plant powder samples had increase while elemental concentrations in the post-hydrotreatment soil samples were decreased. XRF analysis presented a variation in soil elemental composition concentration from anode to cathode where the concentration near anode region increased while decreased near the cathode region. A significant changes in soil pH were obtained where the soil pH increase in cathode region while decrease in anode region. The results reveal that the assistance of EK in phyto remediation process has increase the efficiency of plant uptake. (author)

Remediation of Cd(II)-contaminated soil via humin-enhanced electrokinetic technology.

Science.gov (United States)

Ding, Ling; Lv, Wenying; Yao, Kun; Li, Liming; Wang, Mengmeng; Liu, Guoguang

2017-02-01

Humin is the component of humic substances that is recalcitrant to extraction by either strong bases or strong acids, which contains a variety of functional groups that may combine with heavy metal ions. The present study employed humin as an adsorbent to investigate the efficacy of a remediation strategy under the effects of humin-enhanced electrokinetics. Because the cations gravitate toward cathode and anions are transferred to anode, humin was placed in close proximity to the cathode in the form of a package. The humin was taken out after the experiments to determine whether a target pollutant (cadmium) might be completely removed from soil. Acetic acid-sodium acetate was selected as the electrolyte for these experiments, which was circulated between the two electrode chambers via a peristaltic pump, in order to control the pH of the soil. The results indicated that when the remediation duration was extended to 240 h, the removal of acid extractable Cd(II) could be up to 43.86% efficiency, and the adsorption of the heavy metal within the humin was 86.15 mg/kg. Further, the recycling of the electrolyte exhibited a good control of the pH of the soil. When comparing the pH of the soil with the circulating electrolyte during remediation, in contrast to when it was not being recycled, the pH of the soil at the anode increased from 3.89 to 5.63, whereas the soil at the cathode decreased from 8.06 to 7.10. This indicated that the electrolyte recycling had the capacity to stabilize the pH of the soil.

Microstructures and critical currents in high-Tc superconductors

International Nuclear Information System (INIS)

Suenaga, Masaki

1998-01-01

Microstructural defects are the primary determining factors for the values of critical-current densities in a high T c superconductor after the electronic anisotropy along the a-b plane and the c-direction. A review is made to assess firstly what would be the maximum achievable critical-current density in YBa 2 Cu 3 O 7 if nearly ideal pinning sites were introduced and secondly what types of pinning defects are currently introduced or exist in YBa 2 Cu 3 O 7 and how effective are these in pinning vortices

Characterization of a high-power/current pulsed magnetized arc discharge

NARCIS (Netherlands)

Zielinski, J. J.; van der Meiden, H. J.; Morgan, T. W.; D.C. Schram,; De Temmerman, G.

2012-01-01

A high-power pulsed magnetized arc discharge has been developed to allow the superimposition of a dc plasma and a high-power plasma impulse with a single plasma source. A capacitor bank (8400 mu F) is parallel-coupled to the current regulated power supply. The current is transiently increased from

Characterization of a high-power/current pulsed magnetized arc discharge

NARCIS (Netherlands)

Zielinski, J.J.; Meiden, van der H.J.; Morgan, T.W.; Schram, D.C.; De Temmerman, G.C.

2012-01-01

A high-power pulsed magnetized arc discharge has been developed to allow the superimposition of a dc plasma and a high-power plasma impulse with a single plasma source. A capacitor bank (8400 µF) is parallel-coupled to the current regulated power supply. The current is transiently increased from its

Development of high electrical resistance persistent current switch for high speed energization system

International Nuclear Information System (INIS)

Jizo, Y.; Furuta, Y.; Nakashima, H.

1986-01-01

Japanese National Railways is now developing a superconducting magnetically-levitated train system. A persistent current switch is incorporated in the super-conducting magnet used in the magnetically-levitated train. In recent years, the switch has been required to have higher electrical resistance during its off-state in order to realize the high speed energization/de-energization system of the superconducting magnets. The system aims to decrease evaporation volume of liquid helium during the energization/de-energization of the magnet, by means of energizing the superconducting magnet with high current increasing/decreasing rate. Consequently, it would be possible to decrease the dependence of the on-board magnet system upon the ground cooling system. Through the development of a stable superconductive wire material and a coil structure for the persistent current switch using many small model switches which were produced in order to improve their current carrying capacities, the authors have succeeded in manufacturing the high electrical resistance persistent current switch whose electrical resistance was 5 ohms. The switch, of cylindrical shape, has a diameter of about 100mm, a length of about 100mm. These 5 ohm PCSs are now functioning in stable conditions being incorporated in the superconducting magnets of No.2 vehicle of MLU001 at the JNR's Miyazaki test track. Further, the authors are now developing the PCS of still higher resistance values, such as 50 ohms, through studies for stabilization in structural aspects of the winding and obtaining results therefrom

High-speed radiography and x-ray cinematography by high-current betatrons

International Nuclear Information System (INIS)

Akimochkin, Yu.V.; Akulov, G.V.; Leunov, F.G.; Moskalev, V.A.; Ryabukhin, V.L.

1979-01-01

The paper provides a description of an equipment system comprising a pair of 25 MeV high-current betatrons and an X-ray drum-type cinecamera for high-speed radiography and X-ray cinematography for use when studying dynamics of objects moving at a rate of 0.5 - 3.0 km/s as well as in X-ray cinematography of processes at a rate of up to 1 m/s. (author)

High Field Side Lower Hybrid Current Drive Simulations for Off- axis Current Drive in DIII-D

Directory of Open Access Journals (Sweden)

Wukitch S.J.

2017-01-01

Full Text Available Efficient off-axis current drive scalable to reactors is a key enabling technology for developing economical, steady state tokamak. Previous studies have focussed on high field side (HFS launch of lower hybrid current drive (LHCD in double null configurations in reactor grade plasmas and found improved wave penetration and high current drive efficiency with driven current profile peaked near a normalized radius, ρ, of 0.6-0.8, consistent with advanced tokamak scenarios. Further, HFS launch potentially mitigates plasma material interaction and coupling issues. For this work, we sought credible HFS LHCD scenario for DIII-D advanced tokamak discharges through utilizing advanced ray tracing and Fokker Planck simulation tools (GENRAY+CQL3D constrained by experimental considerations. For a model and existing discharge, HFS LHCD scenarios with excellent wave penetration and current drive were identified. The LHCD is peaked off axis, ρ∼0.6-0.8, with FWHM Δρ=0.2 and driven current up to 0.37 MA/MW coupled. For HFS near mid plane launch, wave penetration is excellent and have access to single pass absorption scenarios for variety of plasmas for n||=2.6-3.4. These DIII-D discharge simulations indicate that HFS LHCD has potential to demonstrate efficient off axis current drive and current profile control in DIII-D existing and model discharge.

High Current Planar Transformer for Very High Efficiency Isolated Boost DC-DC Converters

DEFF Research Database (Denmark)

Pittini, Riccardo; Zhang, Zhe; Andersen, Michael A. E.

2014-01-01

This paper presents a design and optimization of a high current planar transformer for very high efficiency dc-dc isolated boost converters. The analysis considers different winding arrangements, including very high copper thickness windings. The analysis is focused on the winding ac-resistance a......This paper presents a design and optimization of a high current planar transformer for very high efficiency dc-dc isolated boost converters. The analysis considers different winding arrangements, including very high copper thickness windings. The analysis is focused on the winding ac......-resistance and transformer leakage inductance. Design and optimization procedures are validated based on an experimental prototype of a 6 kW dcdc isolated full bridge boost converter developed on fully planar magnetics. The prototype is rated at 30-80 V 0-80 A on the low voltage side and 700-800 V on the high voltage side...... with a peak efficiency of 97.8% at 80 V 3.5 kW. Results highlights that thick copper windings can provide good performance at low switching frequencies due to the high transformer filling factor. PCB windings can also provide very high efficiency if stacked in parallel utilizing the transformer winding window...

Electrokinetic deposition of waterborne, particulate FeO(OH) and MnO2 on stainless steel surfaces

International Nuclear Information System (INIS)

Hermansson, H.-P.

1977-02-01

study forms part of a programme of research into corrosion product behaviour in progress at Aktiebolaget Atomenergi. Attention is in this instance focused on the influence of electrokinetic tic factors upon the deposition of particulate corrosion products. The work has involved the development of experimental apparatus and techniques and the investigation of the deposition characteristics of FeO(OH) and MnO 2 at temperatures below 100 degC. The experimental results indicate that the deposition rate of the compounds under review depends mainly upon the zeta potential (zeta) of the particle and of the test section wall. The deposition rate attains a maximum when the zeta potential is at a minimum or zero. Deposition occurs when zeta approx. < 40 mV. Outside this interval deposition is not observed. Furthermore, the deposition rate maximum depends upon the rate of change of pH both as regards its magnitude and its position on the pH scale. This dependence can be accounted for in terms of a general drain of material from the loop and a difference in zeta potential between particles and the wall surface of the test section. (author)

Electrokinetic deposition of waterborne, particlate FeO(OH) and MnO2 on stainless steel surfaces

International Nuclear Information System (INIS)

Hermansson, H.-P.

1977-01-01

The study forms part of a programme of research into corrosion product behaviour in progress at Studsvik Energiteknik AB. Attention is in this instance focused on the incluence of electrokinetic factors upon the deposition of particulate corrosion products. The work has involved the development of experimental apparatus and techniques and investigation of the deposition characteristics of FeO(OH) and MnO 2 at temperatures below 100 deg C. The experimental results indicate that the deposition rate of the compounds under review depends mainly upon the zeta potential (zeta) of particles and of the test section wall. The deposition rate attains a maximum when the zeta potential is at a minimum or zero. Deposition occurs when |zeta|< approximately 40 m. Outside this interval deposition is not observed. Furthermore, the deposition rate maximum depends upon the rate of change of pH both as regards its magnitude and its position on the pH scale. This dependence can be accounted for in terms of a general drain of material from the loop as deposition proceeds and a difference in zeta potential between particles and the wall surface of the test section. (author)

Low energy current accumulator for high-energy proton rings

International Nuclear Information System (INIS)

Month, M.

1977-01-01

Building current in high-energy p-p colliding beam machines is most appropriately done in a low-energy (small circumference) current accumulator. Three significant factors favor such a procedure: First, large rings tend to be susceptible to unstable longitudinal density oscillations. These can be avoided by pumping up the beam in the accumulator. When the current stack is injected into the storage ring, potentially harmful instability is essentially neutralized. Second, high-field magnets characteristic of future high energy proton rings are designed with superconducting coils within the iron magnetic shield. This means coil construction and placement errors propagate rapidly within the beam aperture. An intermediate ''stacking ring'' allows the minimum use of the superconducting ring aperture. Finally, the coils are vulnerable to radiation heating and possible magnet quenching. By minimizing beam manipulaion in the superconducting environment and using only the central portion of the beam aperture, coil vulnerability can be put at a minimum

Pressurized liquid extracts from Spirulina platensis microalga. Determination of their antioxidant activity and preliminary analysis by micellar electrokinetic chromatography.

Science.gov (United States)

Herrero, Miguel; Ibáñez, Elena; Cifuentes, Alejandro; Señoráns, Javier

2004-08-27

In this work, different extracts from the microalga Spirulina platensis are obtained using pressurized liquid extraction (PLE) and four different solvents (hexane, light petroleum, ethanol and water). Different extraction temperatures (115 and 170 degrees C) were tested using extraction times ranging from 9 to 15 min. The antioxidant activity of the different extracts is determined by means of an in vitro assay using a free radical method. Moreover, a new and fast method is developed using micellar electrokinetic chromatography with diode array detection (MEKC-DAD) to provide a preliminary analysis on the composition of the extracts. This combined application (i.e., in vitro assays plus MEKC-DAD) allowed the fast characterization of the extracts based on their antioxidant activity and the UV-vis spectra of the different compounds found in the extracts. To our knowledge, this work shows for the first time the great possibilities of the combined use of PLE-in vitro assay-MEKC-DAD to investigate natural sources of antioxidants.

High stability, high current DC-power supplies

International Nuclear Information System (INIS)

Hosono, K.; Hatanaka, K.; Itahashi, T.

1995-01-01

Improvements of the power supplies and the control system of the AVF cyclotron which is used as an injector to the ring cyclotron and of the transport system to the ring cyclotron were done in order to get more high quality and more stable beam. The power supply of the main coil of the AVF cyclotron was exchanged to new one. The old DCCTs (zero-flux current transformers) used for the power supplies of the trim coils of the AVF cyclotron were changed to new DCCTs to get more stability. The potentiometers used for the reference voltages in the other power supplies of the AVF cyclotron and the transport system were changed to the temperature controlled DAC method for numerical-value settings. This paper presents the results of the improvements. (author)

Hall probe for measuring high currents in superconducting coils

International Nuclear Information System (INIS)

Ferendeci, A.M.

1986-01-01

Constructional details of a compact Hall probe for measuring high currents in superconducting coils are given. The Hall probe is easy to assemble and can be inserted or removed from the system without breaking the superconducting loop. Upper current limit of the probe can be increased by using larger magnetic core material. Shielding becomes necessary if the probe holder is to be placed near large current dependent magnetic fields

Adaptation of superconducting fault current limiter to high-speed reclosing

International Nuclear Information System (INIS)

Koyama, T.; Yanabu, S.

2009-01-01

Using a high temperature superconductor, we constructed and tested a model superconducting fault current limiter (SFCL). The superconductor might break in some cases because of its excessive generation of heat. Therefore, it is desirable to interrupt early the current that flows to superconductor. So, we proposed the SFCL using an electromagnetic repulsion switch which is composed of a superconductor, a vacuum interrupter and a by-pass coil, and its structure is simple. Duration that the current flow in the superconductor can be easily minimized to the level of less than 0.5 cycle using this equipment. On the other hand, the fault current is also easily limited by large reactance of the parallel coil. There is duty of high-speed reclosing after interrupting fault current in the electric power system. After the fault current is interrupted, the back-up breaker is re-closed within 350 ms. So, the electromagnetic repulsion switch should return to former state and the superconductor should be recovered to superconducting state before high-speed reclosing. Then, we proposed the SFCL using an electromagnetic repulsion switch which employs our new reclosing function. We also studied recovery time of the superconductor, because superconductor should be recovered to superconducting state within 350 ms. In this paper, the recovery time characteristics of the superconducting wire were investigated. Also, we combined the superconductor with the electromagnetic repulsion switch, and we did performance test. As a result, a high-speed reclosing within 350 ms was proven to be possible.

High performance current controller for particle accelerator magnets supply

DEFF Research Database (Denmark)

Maheshwari, Ram Krishan; Bidoggia, Benoit; Munk-Nielsen, Stig

2013-01-01

The electromagnets in modern particle accelerators require high performance power supply whose output is required to track the current reference with a very high accuracy (down to 50 ppm). This demands very high bandwidth controller design. A converter based on buck converter topology is used...

Valley current characterization of high current density resonant tunnelling diodes for terahertz-wave applications

Science.gov (United States)

Jacobs, K. J. P.; Stevens, B. J.; Baba, R.; Wada, O.; Mukai, T.; Hogg, R. A.

2017-10-01

We report valley current characterisation of high current density InGaAs/AlAs/InP resonant tunnelling diodes (RTDs) grown by metal-organic vapour phase epitaxy (MOVPE) for THz emission, with a view to investigate the origin of the valley current and optimize device performance. By applying a dual-pass fabrication technique, we are able to measure the RTD I-V characteristic for different perimeter/area ratios, which uniquely allows us to investigate the contribution of leakage current to the valley current and its effect on the PVCR from a single device. Temperature dependent (20 - 300 K) characteristics for a device are critically analysed and the effect of temperature on the maximum extractable power (PMAX) and the negative differential conductance (NDC) of the device is investigated. By performing theoretical modelling, we are able to explore the effect of typical variations in structural composition during the growth process on the tunnelling properties of the device, and hence the device performance.

Electron gun for formation of two high-current beams

International Nuclear Information System (INIS)

Borisov, A.R.; Zherlitsyn, A.G.; Mel'nikov, G.V.; Shtejn, Yu.G.

1982-01-01

The design of the ''Tonus'' accelerator electron gun for formation of two high-current beams aiming at the production of the maximum beam power and density is described. The results of investigation of two modes of beam formation are presented. In the first variant the beams were produced by means of two plane diodes with 40 mm diameter cathodes made of stainless steel and anodes made of 50 μm thick titanium foil. In the second variant the beams were formed by means of two coaxial diodes with magnetic insulation. In one diode the cathode diameter equals to 74 mm, the anode diameter - 92 mm, in the other diode 16 and 44 mm respectively. Current redistribution in the diodes and its effect on accelerating voltage are investigated. It is shown that the gun permits formation of synchronized two high-current beams, iaving equal electron energied. Wide range current control of both beams is possible

[Analysis of phthalate esters in plastic-packaging bags on-line sample stacking-microemulsion electrokinetic chromatography].

Science.gov (United States)

Xiao, Jia; Huang, Ying; Wang, Minyi; Chen, Guonan

2012-09-01

Two convenient, effective, and reproducible methods using microemulsion electrokinetic chromatography (MEEKC)-normal stacking mode (NSM) and reversed electrode polarity stacking mode (REPSM) were developed for the on-line sample stacking of phthalate esters (PAEs). REPSM coupled with MEEKC increased the sensitivity of 937.5 to 7,143 times for four PAEs compared to the conventional MEEKC. The separating conditions in the MEEKC method were studied, and many factors influencing the two sample stacking processes were investigated in detail. The optimum sample matrices for the two stacking methods were as follows: 30 mmol/L sodium cholate (SC) and 30.0 mmol/L borate (pH 8.5). Additionally, sample injections as large as 3.45 kPa x 40 s and 3.45 kPa x 90 s were applied for NSM-MEEKC and REPSM-MEEKC, respectively. The linear relationship and reproducibility were also examined. Under the optimum conditions, the detection limits (S/N = 3) of the PAEs were in the ranges of 0.021 - 0.33 mg/L and 0.7 - 4 microg/L for NSM-MEEKC and REPSM-MEEKC, respectively. The proposed REPSM-MEEKC has been successfully applied to determine PAEs in plastic-packaging bags, and the spiked recoveries were in the range of 89.1% - 105.6% with satisfactory results.

Quench propagation in High Temperature Superconducting materials integrated in high current leads

CERN Document Server

Milani, D

2001-01-01

High temperature superconductors (HTS) have been integrated in the high current leads for the Large Hadron Collider (LHC), under construction at CERN, in order to reduce the heat leak into the liquid helium bath due to the joule effect. The use of the HTS technology in the lower part of the current leads allowed to significantly reduce the heat charge on the cryogenic system. Hybrid current leads have been designed to fulfill the LHC requirements with respect to thermal load; several tests have been performed to study the lead behavior especially during a quench transient. Quench experiments have been performed at CERN on 13 kA prototypes to determine the adequate design and protection. In all the tests it is possible to know the temperature profile of the HTS only with the help of quench simulations that model the thermo-hydraulic processes during quench. The development of a theoretical model for the simulation allows reducing the number of test to perform and to scale the experimental result to other curre...

Treatment of a suspension of PCB contaminated soil using iron nanoparticles and electric current

DEFF Research Database (Denmark)

Comes, Helena I.; Ottosen, Lisbeth M.; Ribeiro, Alexandra B.

2015-01-01

Contaminated soils and sediments with polychlorinated biphenyls (PCB) are an important environmental problem due to the persistence of these synthetic aromatic compounds and to the lack of a cost-effective and sustainable remediation technology. Recently, a new experimental setup has been proposed...... using electrodialytic remediation and iron nanoparticles. The current work compares the performance of this new setup (A) with conventional electrokinetics (setup B). An historically contaminated soil with an initial PCB concentration of 258 mu g kg-1 was treated during 5, 10, 20 and 45 d using...... different amounts of iron nanoparticles in both setups A and B. A PCB removal of 83% was obtained in setup A compared with 58% of setup B. Setup A also showed additional advantages, such as a higher PCB dechlorination, in a shorter time, with lower nZVI consumption, and with the use of half of the voltage...

High current superconductors for DEMO

Energy Technology Data Exchange (ETDEWEB)

Bruzzone, Pierluigi, E-mail: pierluigi.bruzzone@psi.ch [Ecole Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas (CRPP), Association Euratom – Confédération Suisse, CH-5232 Villigen PSI (Switzerland); Sedlak, Kamil; Stepanov, Boris [Ecole Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas (CRPP), Association Euratom – Confédération Suisse, CH-5232 Villigen PSI (Switzerland)

2013-10-15

Highlights: ► Definition of requirement for TF coil based on the input of system code. ► A TF coil and conductor design for the European DEMO project. ► Use of React and Wind method opposite to Wind and React with related advantages. ► Hybridization of winding pack, Nb/Nb{sub 3}Sn, by graded layer winding. -- Abstract: In the assumption that DEMO will be an inductively driven tokamak, the number of load cycles will be in the range of several hundred thousands. The requirements for a new generation of Nb{sub 3}Sn based high current conductors for DEMO are drafted starting from the output of system code PROCESS. The key objectives include the stability of the DC performance over the lifetime of the machine and the effective use of the Nb{sub 3}Sn strand properties, for cost and reliability reasons. A preliminary layout of the winding pack and conductors for the toroidal field magnets is presented. To suppress the mechanism of reversible and irreversible degradation, i.e. to preserve in the cabled conductor the high critical current density of the strand, the thermal strain must be insignificant and no space for micro-bending under transverse load must be left in the strand bundle. The “react-and-wind” method is preferred here, with a graded, layer wound magnet, containing both Nb{sub 3}Sn and NbTi layers. The implications of the conductor choice on the coil design and technology are highlighted. A roadmap is sketched for the development of a full size prototype conductor sample and demonstration of the key technologies.

Development of pulsed high current drivers for fast Z-pinch

International Nuclear Information System (INIS)

Sun Fengju; Qiu Aici; Zeng Zhengzhong; Zeng Jiangtao; Kuai Bin; Yang Hailiang

2006-01-01

It is required that the peak current of high power pulsed drive for fast Z-pinch reaches 60 MA to realize inertial confine fusion (ICF) and high yield (HY). With the conventional technological methods similar to the Z or Saturn apparatus, increasing driver current further is impractical and difficult according to the cost, structure complexity and reliability of the driver, so it is necessary to develop novel fast pulsed high current driver. The present art-of-state and trends of fast Z-pinch driver are summarized, and the typical conceptual designs and technological methods on ICF/HY PRS (plasma radiation source) and destroying-level super X-ray simulators in USA and Russia are outlined, such as HCEI's UGXX1 driver and new Saturn driver based on fast linear transformer driver (FLTD) and novel driver based on fast Marx generator (FMG) with current of 15 MA. The crucial technological problems and requirements to investigate in the future are presented. (authors)

High performance current generator with one-picoampere resolution

International Nuclear Information System (INIS)

Grillo, L.; Manfredi, P.F.; Marchesini, R.

1975-01-01

A high-performance current generator for the picoampere region is presented. Although it was primarily developed as a part of an automatic test system to calibrate charge integrators for accelerating machines. It can suit a wide range of applications. It consists basically of a positive feedback loop of controlled gain which includes a varactor bridge operational amplifier. The essential features of the instrument are a 1 pA resolution and a 10 15 Ω output impedance. The output is guarded and floating between - 120 V and + 120 V, and the voltage across the external loads is measured without affecting the delivered current by a digital panel meter on the front panel. The unit can therefore operate as a high-accuracy dc impedance meter. (Auth.)

Testing and evaluation of high temperature superconductor current leads

International Nuclear Information System (INIS)

Yadav, Anand; Puntambekar, Avinash; Manekar, M.A.

2009-01-01

National Institute for Inter-disciplinary Science and Technology (NIIST), Council of Scientific and Industrial Research, Trivandrum (formerly Regional Research Laboratory) has accomplished a DAE-BRNS project with Raja Ramanna Centre for Advanced Technology (RRCAT) as principal collaborator for the development of high temperature superconductor (HTS) current leads. These HTS current leads have self-field critical currents (Ic) ranging from 50 A to 1000 A at liquid nitrogen (LN 2 ) temperature. These HTS are made out of silver sheathed Bismuth Strontium Calcium Copper Oxide (BSCCO-2223), for direct application in superconducting (SC) systems involving transportation of high electric currents from power sources at room temperature to superconducting devices at cryogenic temperatures. RRCAT has participated in this project by testing and evaluation of these HTS current leads and carried out actual load trials. In this paper, we will describe the HTS testing setup, tests performed with their testing procedure and the test results. The testing of these HTS has been done with joint effort of Materials Advanced Accelerator Science and Cryogenics Div. and Superconducting Technology Lab (SCT Lab), Advanced Accelerator Module Development Div., using the test facility available at the SCT Lab. (author)

Broad-beam, high current, metal ion implantation facility

International Nuclear Information System (INIS)

Brown, I.G.; Dickinson, M.R.; Galvin, J.E.; Godechot, X.; MacGill, R.A.

1990-07-01

We have developed a high current metal ion implantation facility with which high current beams of virtually all the solid metals of the Periodic Table can be produced. The facility makes use of a metal vapor vacuum arc ion source which is operated in a pulsed mode, with pulse width 0.25 ms and repetition rate up to 100 pps. Beam extraction voltage is up to 100 kV, corresponding to an ion energy of up to several hundred keV because of the ion charge state multiplicity; beam current is up to several Amperes peak and around 10 mA time averaged delivered onto target. Implantation is done in a broad-beam mode, with a direct line-of-sight from ion source to target. Here we describe the facility and some of the implants that have been carried out using it, including the 'seeding' of silicon wafers prior to CVD with titanium, palladium or tungsten, the formation of buried iridium silicide layers, and actinide (uranium and thorium) doping of III-V compounds. 16 refs., 6 figs

Processing and critical currents of high-Tc superconductor wires

International Nuclear Information System (INIS)

Krauth, H.; Heine, K.; Tenbrink, J.

1991-01-01

High-Tc superconductors are expected to have a major impact on magnet and energy technology. For technical applications they have to fulfill the requirement of carrying sufficient current at a critical current density of the order of 10 5 A/cm 2 at operating temperature and magnetic field. At 77 K these values have not been achieved yet in bulk material or wires due to weak link problems and flux creep effects. Progress made so far and remaining problems will be discussed in detail concentrating on problems concerning development of technical wires. In Bi-based materials technically interesting critical current densities could be achieved at 4.2 K in fields above 20 T (1,2), rendering possible the use of such material for very high field application. (orig.)

On-line identification of lysergic acid diethylamide (LSD) in tablets using a combination of a sweeping technique and micellar electrokinetic chromatography/77 K fluorescence spectroscopy.

Science.gov (United States)

Fang, Ching; Liu, Ju-Tsung; Lin, Cheng-Huang

2003-03-01

This work describes a novel method for the accurate determination of lysergic acid diethylamide (LSD) in tablets. A technique involving sweeping-micellar electrokinetic chromatography (MEKC) was used for the initial on-line concentration and separation, after which a cryogenic molecular fluorescence experiment was performed at 77 K. Using this approach, not only the separation of LSD from the tablet extract was achieved, but on-line spectra were readily distinguishable and could be unambiguously assigned. The results are in agreement with analyses by gas chromatography-mass spectrometry (GC-MS). Thus, this method, which was found to be accurate, sensitive and rapid, has the potential for use as a reliable complementary method to GC-MS in such analyses.

Quench protection and design of large high-current-density superconducting magnets

International Nuclear Information System (INIS)

Green, M.A.

1981-03-01

Although most large superconducting magnets have been designed using the concept of cryostability, there is increased need for large magnets which operate at current densities above the cryostable limit (greater than 10 8 Am -2 ). Large high current density superconducting magnets are chosen for the following reasons: reduced mass, reduced coil thickness or size, and reduced cost. The design of large high current density, adiabatically stable, superconducting magnets requires a very different set of design rules than either large cryostable superconducting magnets or small self-protected high current density magnets. The problems associated with large high current density superconducting magnets fall into three categories; (a) quench protection, (b) stress and training, and (c) cryogenic design. The three categories must be considered simultaneously. The paper discusses quench protection and its implication for magnets of large stored energies (this includes strings of smaller magnets). Training and its relationship to quench protection and magnetic strain are discussed. Examples of magnets, built at the Lawrence Berkeley Laboratory and elsewhere using the design guidelines given in this report, are presented

High current beam transport experiments at GSI

International Nuclear Information System (INIS)

Klabunde, J.; Schonlein, A.; Spadtke, P.

1985-01-01

The status of the high current ion beam transport experiment is reported. 190 keV Ar 1+ ions were injected into six periods of a magnetic quadrupole channel. Since the pulse length is > 0.5 ms partial space charge neutralization occurs. In our experiments, the behavior of unneutralized and partially space charge compensated beams is compared. With an unneutralized beam, emittance growth has been measured for high intensities even in case of the zero-current phase advance sigma 0 0 . This initial emittance growth at high tune depression we attribute to the homogenization effect of the space charge density. An analytical formula based on this assumption describes the emittance growth very well. Furthermore the predicted envelope instabilities for sigma 0 > 90 0 were observed even after 6 periods. In agreement with the theory, unstable beam transport was also experimentally found if a beam with different emittances in the two transverse phase planes was injected into the transport channel. Although the space charge force is reduced for a partially neutralized beam a deterioration of the beam quality was measured in a certain range of beam parameters. Only in the range where an unneutralized beam shows the initial emittance growth, the partial neutralization reduces this effect, otherwise the partially neutralized beam is more unstable

High-energy tritium beams as current drivers in tokamak reactors

International Nuclear Information System (INIS)

Mikkelsen, D.R.; Grisham, L.R.

1983-04-01

The effect on neutral-beam design and reactor performance of using high-energy (approx. 3-10 MeV) tritium neutral beams to drive steady-state tokamak reactors is considered. The lower current of such beams leads to several advantages over lower-energy neutral beams. The major disadvantage is the reduction of the reactor output caused by the lower current-drive efficiency of the high-energy beams

Enhanced performance on high current discharges in JET produced by ICRF heating during the current rise

International Nuclear Information System (INIS)

Bures, M.; Bhatnagar, V.; Cotrell, G.; Corti, S.; Christiansen, J.P.; Hellsten, T.; Jacquinot, J.; Lallia, P.; Lomas, P.; O'Rourke, J.; Taroni, A.; Tibone, F.; Start, D.F.H.

1989-01-01

The performance of high current discharges can be increased by applying central ICRF heating before or shortly after the onset of sawtooth activity in the plasma current rise phase. Sawtooth-free periods have been obtained resulting in the enhanced discharge performance. High T e (0) 9 - 10.5 keV with peaked profiles T e (0)/ e > = 3 - 4 were obtained giving values of n e (0)T e (0) up to 6x10 20 (keV m -3 ). Improvements in T i (0) and neutron production are observed. A 60 % enhancement in D-D reaction rate from 2nd harmonic deuterium (2ω CD ) heating appears to be present. In all current rise (CR) discharges radiation amounts to 25-50 % of total power. (author) 4 refs., 6 figs

Sub-Grid Modeling of Electrokinetic Effects in Micro Flows

Science.gov (United States)

Chen, C. P.

2005-01-01

Advances in micro-fabrication processes have generated tremendous interests in miniaturizing chemical and biomedical analyses into integrated microsystems (Lab-on-Chip devices). To successfully design and operate the micro fluidics system, it is essential to understand the fundamental fluid flow phenomena when channel sizes are shrink to micron or even nano dimensions. One important phenomenon is the electro kinetic effect in micro/nano channels due to the existence of the electrical double layer (EDL) near a solid-liquid interface. Not only EDL is responsible for electro-osmosis pumping when an electric field parallel to the surface is imposed, EDL also causes extra flow resistance (the electro-viscous effect) and flow anomaly (such as early transition from laminar to turbulent flow) observed in pressure-driven microchannel flows. Modeling and simulation of electro-kinetic effects on micro flows poses significant numerical challenge due to the fact that the sizes of the double layer (10 nm up to microns) are very thin compared to channel width (can be up to 100 s of m). Since the typical thickness of the double layer is extremely small compared to the channel width, it would be computationally very costly to capture the velocity profile inside the double layer by placing sufficient number of grid cells in the layer to resolve the velocity changes, especially in complex, 3-d geometries. Existing approaches using "slip" wall velocity and augmented double layer are difficult to use when the flow geometry is complicated, e.g. flow in a T-junction, X-junction, etc. In order to overcome the difficulties arising from those two approaches, we have developed a sub-grid integration method to properly account for the physics of the double layer. The integration approach can be used on simple or complicated flow geometries. Resolution of the double layer is not needed in this approach, and the effects of the double layer can be accounted for at the same time. With this

A review of high beam current RFQ accelerators and funnels

International Nuclear Information System (INIS)

Schneider, J.D.

1998-01-01

The authors review the design features of several high-current (> 20-mA) and high-power (> 1-mA average) proton or H - injectors, RFQs, and funnels. They include a summary of observed performance and will mention a sampling of new designs, including the proposed incorporation of beam choppers. Different programs and organizations have chosen to build the RFQ in diverse configurations. Although the majority of RFQs are either low-current or very low duty-factor, several versions have included high-current and/or high-power designs for either protons or H - ions. The challenges of cooling, handling high space-charge forces, and coupling with injectors and subsequent accelerators are significant. In all instances, beam tests were a valuable learning experience, because not always did these as-built structures perform exactly as predicted by the earlier design codes. They summarize the key operational parameters, indicate what was achieved, and highlight what was learned in these tests. Based on this generally good performance and high promise, even more challenging designs are being considered for new applications that include even higher powers, beam funnels and choppers

Compilation of current high-energy-physics experiments

International Nuclear Information System (INIS)

Wohl, C.G.; Kelly, R.L.; Armstrong, F.E.

1980-04-01

This is the third edition of a compilation of current high energy physics experiments. It is a collaborative effort of the Berkeley Particle Data Group, the SLAC library, and ten participating laboratories: Argonne (ANL), Brookhaven (BNL), CERN, DESY, Fermilab (FNAL), the Institute for Nuclear Study, Tokyo (INS), KEK, Rutherford (RHEL), Serpukhov (SERP), and SLAC. The compilation includes summaries of all high energy physics experiments at the above laboratories that (1) were approved (and not subsequently withdrawn) before about January 1980, and (2) had not completed taking of data by 1 January 1976

Application of radiofrequency superconductivity to accelerators for high-current ion beams

International Nuclear Information System (INIS)

Delayen, J.R.; Bohn, C.L.; Kennedy, W.L.; Roche, C.T.; Sagalovsky, L.

1992-01-01

A development program is underway to apply rf superconductivity to the design of continuous-wave (cw) linear accelerators for high-current, high-brightness ion beam. During the last few years, considerable progress has been made both experimentally and theoretically toward this application. Recent tests of niobium resonators for ion acceleration have yielded average accelerating gradients as high as 18 MV/m. In an experiment with a radio-frequency quadrupole geometry, niobium was found to sustain cw peak surface electric fields as high as 128 MV/m over large (10 cm) surface areas. Theoretical studies of beam halo, cumulative beam breakup and alternating-phase focusing have also yielded important results. This paper su-summarizes the recent progress and identifies current and future work in the areas of superconducting accelerator technology for high-current ion beams

MHD Modeling of Conductors at Ultra-High Current Density

International Nuclear Information System (INIS)

ROSENTHAL, STEPHEN E.; DESJARLAIS, MICHAEL P.; SPIELMAN, RICK B.; STYGAR, WILLIAM A.; ASAY, JAMES R.; DOUGLAS, M.R.; HALL, C.A.; FRESE, M.H.; MORSE, R.L.; REISMAN, D.B.

2000-01-01

In conjunction with ongoing high-current experiments on Sandia National Laboratories' Z accelerator, the authors have revisited a problem first described in detail by Heinz Knoepfel. Unlike the 1-Tesla MITLs of pulsed power accelerators used to produce intense particle beams, Z's disc transmission line (downstream of the current addition) is in a 100--1,200 Tesla regime, so its conductors cannot be modeled simply as static infinite conductivity boundaries. Using the MHD code MACH2 they have been investigating the conductor hydrodynamics, characterizing the joule heating, magnetic field diffusion, and material deformation, pressure, and velocity over a range of current densities, current rise-times, and conductor materials. Three purposes of this work are (1) to quantify power flow losses owing to ultra-high magnetic fields, (2) to model the response of VISAR diagnostic samples in various configurations on Z, and (3) to incorporate the most appropriate equation of state and conductivity models into the MHD computations. Certain features are strongly dependent on the details of the conductivity model

MHD Modeling of Conductors at Ultra-High Current Density

International Nuclear Information System (INIS)

Rosenthal, S.E.; Asay, J.R.; Desjarlais, M.P.; Douglas, M.R.; Frese, M.H.; Hall, C.A.; Morse, R.L.; Reisman, D.; Spielman, R.B.; Stygar, W.A.

1999-01-01

In conjunction with ongoing high-current experiments on Sandia National Laboratories' Z accelerator we have revisited a problem first described in detail by Heinz Knoepfel. MITLs of previous pulsed power accelerators have been in the 1-Tesla regime. Z's disc transmission line (downstream of the current addition) is in a 100-1200 Tesla regime, so its conductors cannot be modeled simply as static infinite conductivity boundaries. Using the MHD code MACH2 we have been investigating conductor hydrodynamics, characterizing the joule heating, magnetic field diffusion, and material deformation, pressure, and velocity over a range of current densities, current rise-times, and conductor materials. Three purposes of this work are ( 1) to quantify power flow losses owing to ultra-high magnetic fields, (2) to model the response of VISAR diagnostic samples in various configurations on Z, and (3) to incorporate the most appropriate equation of state and conductivity models into our MHD computations. Certain features are strongly dependent on the details of the conductivity model. Comparison with measurements on Z will be discussed

Development of the High Current Ion Source for Neutral Beam Injection

Energy Technology Data Exchange (ETDEWEB)

Lee, Hun Ju; Kim, S. H.; Jang, D. H. [Jae Ju University, Jaeju (Korea, Republic of)

1997-08-01

The scope of the 1st year research is to design an 140keV deuterium ion source which has a beam current of 30-40A. According to the collected data, the model of an ion source for NBI of KSTAR was established. The negative ion source, which has good neutralization effecting in high energy, was selected. To generate a plasma, the thoriated tungsten filament was adopted. To increase the efficiency of plasma, the multi cusp type magnetic field was attached. The magnetic field was calculated by POISSON code. The extraction structure was designed with EGUN code, to extract the high quality ion beam. The design of a high current ion source for NBI was carried out. To develop the high current ion source with the high operational stability and the long lifetime, the parameters including an arc current, gas pressure and extraction voltage should be optimized. If designed ion source would be fabricated, its parameters could be optimized experimentally. Through the optimization of the ion source parameter, the core technology for NBI is established and the experiment of current drive in the fusion device can be performed. This technology also can be applied to the synthesis of new material and semiconductor industry. 18 refs., 11 tabs., 19 figs. (author)