On parasupersymmetries and relativistic descriptions for spin one particles. Pt. 2. The interacting context with (electro)magnetic fields

International Nuclear Information System (INIS)

Beckers, J.; Debergh, N.; Nikitin, A.G.

1995-01-01

This second part belongs to a series of two papers devoted to a constructive review of the relativistic wave equations for vector mesons due to the recent impact of spin one developments in connection with parasupersymmetric quantum mechanics. Here, the mesons are interacting with external (electro)magnetic fields but the simplest context of homogeneous constant magnetic fields directed along the z-axis is particularly studied. Discussions on reality of energy eigenvalues, on causal propagation and on gyromagnetic ratios are especially presented. Supersymmetries and parasupersymmetries are analysed with respect to new pseudosupersymmetries suggested by these developments in one particular context. (orig.)

Removal of citrate and hypophosphite binary components using Fenton, photo-Fenton and electro-Fenton processes

Institute of Scientific and Technical Information of China (English)

Yao-Hui Huang; Hsiao-Ting Su; Li-Way Lin

2009-01-01

Both citrate and hypophosphite in aqueous solution were degraded by advanced oxidation processes (Fe2+/H2O2, UV/Fe2+/H2O2, and electrolysis/ Fe2+/H2O2) in this study. Comparison of these techniques in oxidation efficiency was undertaken. It was found that Fenton process could not degrade completely citrate in the presence of hypophosphite since it caused a series inhibition. Therefore, UV light (photo-Fenton) or electron current (electro-Fenton) was applied to improve the degradation efficiency of the Fenton process. Results showed that both photo-Fenton and electro-Fenton processes could overcome the inhibition of hypophosphite, especially the electro-Fenton.

Transparent nanocrystalline ZnO films prepared by spin coating

Energy Technology Data Exchange (ETDEWEB)

Berber, M. [SusTech GmbH and Co. KG, Petersenstr. 20, 64287 Darmstadt, Hessen (Germany)]. E-mail: mete.berber@sustech.de; Bulto, V. [SusTech GmbH and Co. KG, Petersenstr. 20, 64287 Darmstadt, Hessen (Germany); Kliss, R. [SusTech GmbH and Co. KG, Petersenstr. 20, 64287 Darmstadt, Hessen (Germany); Hahn, H. [SusTech GmbH and Co. KG, Petersenstr. 20, 64287 Darmstadt, Hessen (Germany); Forschungszentrum Karlsruhe, Institute for Nanotechnology, Postfach 3640, 76021 Karlsruhe (Germany); Joint Research Laboratory Nanomaterials, TU Darmstadt, Institute of Materials Science, Petersenstr. 23, 64287 Darmstadt (Germany)

2005-09-15

Dispersions of zinc oxide nanoparticles synthesized by the electrochemical deposition under oxidizing conditions process with organic surfactants, were spin coated on glass substrates. After sintering, the microstructure, surface morphology, and electro-optical properties of the transparent nanocrystalline zinc oxide films have been investigated for different coating thicknesses and organic solvents.

Transparent nanocrystalline ZnO films prepared by spin coating

International Nuclear Information System (INIS)

Berber, M.; Bulto, V.; Kliss, R.; Hahn, H.

2005-01-01

Dispersions of zinc oxide nanoparticles synthesized by the electrochemical deposition under oxidizing conditions process with organic surfactants, were spin coated on glass substrates. After sintering, the microstructure, surface morphology, and electro-optical properties of the transparent nanocrystalline zinc oxide films have been investigated for different coating thicknesses and organic solvents

Development of low-k materials by spin-on using radiation

International Nuclear Information System (INIS)

Lee, Young Seak; Ryu, Seung Kon; Im, Ji Sun; Jung, Min Jung; Kim, Sang Jin; Bai, Byong Chol

2010-05-01

Establishment of dispersion technology to precursor solution like polycarbosilane, polyvinylsilane for carbons (carbon nanotubes, carbon blacks, graphites, etc.) and metalic conductive infills. Preparation technology and characterization for silicon carbide fiber having developed electro conductivity and heat resistance by melting and electro spinning. In this study, development of the new functional technique for application of SiC fiber using electro/melting spinning and sintering method. Extension to economical industrial field from the national strategy industrial field. Ultra high temperature materials for new energy technology like nuclear fusion. Extension of SiC application fields according to development of electrical conductivity

Current advances and trends in electro-Fenton process using heterogeneous catalysts - A review.

Science.gov (United States)

Poza-Nogueiras, Verónica; Rosales, Emilio; Pazos, Marta; Sanromán, M Ángeles

2018-06-01

Over the last decades, advanced oxidation processes have often been used alone, or combined with other techniques, for remediation of ground and surface water pollutants. The application of heterogeneous catalysis to electrochemical advanced oxidation processes is especially useful due to its efficiency and environmental safety. Among those processes, electro-Fenton stands out as the one in which heterogeneous catalysis has been broadly applied. Thus, this review has introduced an up-to-date collation of the current knowledge of the heterogeneous electro-Fenton process, highlighting recent advances in the use of different catalysts such as iron minerals (pyrite, magnetite or goethite), prepared catalysts by the load of metals in inorganic and organic materials, nanoparticles, and the inclusion of catalysts on the cathode. The effects of physical-chemical parameters as well as the mechanisms involved are critically assessed. Finally, although the utilization of this process to remediation of wastewater overwhelmingly outnumber other utilities, several applications have been described in the context of regeneration of adsorbent or the remediation of soils as clear examples of the feasibility of the electro-Fenton process to solve different environmental problems. Copyright © 2018 Elsevier Ltd. All rights reserved.

Numerical and experimental study on the steady cone-jet mode of electro-centrifugal spinning

Science.gov (United States)

Hashemi, Ali Reza; Pishevar, Ahmad Reza; Valipouri, Afsaneh; Pǎrǎu, Emilian I.

2018-01-01

This study focuses on a numerical investigation of an initial stable jet through the air-sealed electro-centrifugal spinning process, which is known as a viable method for the mass production of nanofibers. A liquid jet undergoing electric and centrifugal forces, as well as other forces, first travels in a stable trajectory and then goes through an unstable curled path to the collector. In numerical modeling, hydrodynamic equations have been solved using the perturbation method—and the boundary integral method has been implemented to efficiently solve the electric potential equation. Hydrodynamic equations have been coupled with the electric field using stress boundary conditions at the fluid-fluid interface. Perturbation equations were discretized by a second order finite difference method, and the Newton method was implemented to solve the discretized non-linear system. Also, the boundary element method was utilized to solve electrostatic equations. In the theoretical study, the fluid was described as a leaky dielectric with charges only on the surface of the jet traveling in dielectric air. The effect of the electric field induced around the nozzle tip on the jet instability and trajectory deviation was also experimentally studied through plate-plate geometry as well as point-plate geometry. It was numerically found that the centrifugal force prevails on electric force by increasing the rotational speed. Therefore, the alteration of the applied voltage does not significantly affect the jet thinning profile or the jet trajectory.

Preparation and Adsorption Property of Imido-acetic Acid Type Chelating Nano-fibers by Electro-spinning Technique

Science.gov (United States)

Yang, Jiali; Lu, Lansi; Zhang, Zhu; Liao, Minhui; He, Huirong; Li, Lingxing; Chen, Jida; Chen, Shijin

2017-12-01

A novel nano-fibrous adsorbent from imino-acetic acid (IDA) and polyvinyl alcohol (PVA) mixture solution was prepared by electro-spinning technique. The nano-fibrous adsorbents with imino-acetic acid functional groups were characterized and demonstrated by fourier transform infrared spectrometry (FT-IR) and the scanning electron microscopy (SEM). The effect of the adsorbents to remove heavy metals such as lead (Pb) and copper (Cu) ions from the aqueous solution was studied. The maximum adsorption percentage (SP) of the metal ions can reach 93.08% for Cu (II) and 96.69% for Pb(II), respectively. Furthermore, it shows that the adsorption procedure of the adsorbents is spontaneous and endothermic, and adsorption rate fits well with pseudo-second-order kinetic model. Most importantly, the reusability of the nanofibers for removal of metal ions was also demonstrated to be used at least five times.

Bio-Electro-Fenton process for the degradation of Non-Steroidal Anti-Inflammatory Drugs in wastewater

DEFF Research Database (Denmark)

Nadais, Helena; Li, Xiaohu; Alves, Nadine

2018-01-01

Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) are ubiquitous municipal wastewater pollutants of which several are resistant to degradation in conventional wastewater treatment, and represent a major environmental health concern worldwide. An alternative treatment, the bio-electro-Fenton process......, has received increasing attention in past years. In this process the strong oxidant •HO is formed using the electrons derived from bacterial oxidation of organic substrate. In this work, a laboratory scale microbial electrolysis cell based bio-electro-Fenton process was developed for the treatment...

Application of Electro-Fenton Technology to Remediation of Polluted Effluents by Self-Sustaining Process

Directory of Open Access Journals (Sweden)

Maria Ángeles Fernández de Dios

2014-01-01

Full Text Available The applicability of electro-Fenton technology to remediation of wastewater contaminated by several organic pollutants such as dyes and polycyclic aromatic hydrocarbons has been evaluated using iron-enriched zeolite as heterogeneous catalyst. The electro-Fenton technology is an advanced oxidation process that is efficient for the degradation of organic pollutants, but it suffers from the high operating costs due to the need for power investment. For this reason, in this study microbial fuel cells (MFCs were designed in order to supply electricity to electro-Fenton processes and to achieve high treatment efficiency at low cost. Initially, the effect of key parameters on the MFC power generation was evaluated. Afterwards, the degradation of Reactive Black 5 dye and phenanthrene was evaluated in an electro-Fenton reactor, containing iron-enriched zeolite as catalyst, using the electricity supplied by the MFC. Near complete dye decolourization and 78% of phenanthrene degradation were reached after 90 min and 30 h, respectively. Furthermore, preliminary reusability tests of the developed catalyst showed high degradation levels for successive cycles. The results permit concluding that the integrated system is adequate to achieve high treatment efficiency with low electrical consumption.

Application of Electro-Fenton Technology to Remediation of Polluted Effluents by Self-Sustaining Process

Science.gov (United States)

Fernández de Dios, Maria Ángeles; Iglesias, Olaia; Pazos, Marta; Sanromán, Maria Ángeles

2014-01-01

The applicability of electro-Fenton technology to remediation of wastewater contaminated by several organic pollutants such as dyes and polycyclic aromatic hydrocarbons has been evaluated using iron-enriched zeolite as heterogeneous catalyst. The electro-Fenton technology is an advanced oxidation process that is efficient for the degradation of organic pollutants, but it suffers from the high operating costs due to the need for power investment. For this reason, in this study microbial fuel cells (MFCs) were designed in order to supply electricity to electro-Fenton processes and to achieve high treatment efficiency at low cost. Initially, the effect of key parameters on the MFC power generation was evaluated. Afterwards, the degradation of Reactive Black 5 dye and phenanthrene was evaluated in an electro-Fenton reactor, containing iron-enriched zeolite as catalyst, using the electricity supplied by the MFC. Near complete dye decolourization and 78% of phenanthrene degradation were reached after 90 min and 30 h, respectively. Furthermore, preliminary reusability tests of the developed catalyst showed high degradation levels for successive cycles. The results permit concluding that the integrated system is adequate to achieve high treatment efficiency with low electrical consumption. PMID:24723828

Optical modulation techniques for analog signal processing and CMOS compatible electro-optic modulation

Science.gov (United States)

Gill, Douglas M.; Rasras, Mahmoud; Tu, Kun-Yii; Chen, Young-Kai; White, Alice E.; Patel, Sanjay S.; Carothers, Daniel; Pomerene, Andrew; Kamocsai, Robert; Beattie, James; Kopa, Anthony; Apsel, Alyssa; Beals, Mark; Mitchel, Jurgen; Liu, Jifeng; Kimerling, Lionel C.

2008-02-01

Integrating electronic and photonic functions onto a single silicon-based chip using techniques compatible with mass-production CMOS electronics will enable new design paradigms for existing system architectures and open new opportunities for electro-optic applications with the potential to dramatically change the management, cost, footprint, weight, and power consumption of today's communication systems. While broadband analog system applications represent a smaller volume market than that for digital data transmission, there are significant deployments of analog electro-optic systems for commercial and military applications. Broadband linear modulation is a critical building block in optical analog signal processing and also could have significant applications in digital communication systems. Recently, broadband electro-optic modulators on a silicon platform have been demonstrated based on the plasma dispersion effect. The use of the plasma dispersion effect within a CMOS compatible waveguide creates new challenges and opportunities for analog signal processing since the index and propagation loss change within the waveguide during modulation. We will review the current status of silicon-based electrooptic modulators and also linearization techniques for optical modulation.

EPR Studies of Spin-Spin Exchange Processes: A Physical Chemistry Experiment.

Science.gov (United States)

Eastman, Michael P.

1982-01-01

Theoretical background, experimental procedures, and analysis of experimental results are provided for an undergraduate physical chemistry experiment on electron paramagnetic resonance (EPR) linewidths. Source of line broadening observed in a spin-spin exchange process between radicals formed in aqueous solutions of potassium peroxylamine…

Influence of anionic surfactant on the process of electro-Fenton decolorized methyl orange.

Science.gov (United States)

Ren, B X

2010-01-01

The electro-Fenton process has been shown to be very successful to remove dyes from water. However, the influence of other constituents in dyeing industry wastewater, such as Sodium Dodecyl Sulfate (SDS) surfactants, has not been investigated. In this study, the effect of SDS surfactant on the kinetics of Methyl Orange degradation undergoing Electro-Fenton process was investigated. Results show that Methyl Orange degradation rate decreased as SDS concentration (below Critical Micelle Concentration, CMC) increased, which was attributed to the consumption of hydroxyl radicals (( )OH) by surfactants. The kinetics modeling indicates the reaction was the first-order reaction to Methyl Orange even SDS existing. The pseudo first-order rate constants decreased as SDS concentration increased.

Collisional Penrose process with spinning particles

Science.gov (United States)

Mukherjee, Sajal

2018-03-01

In this article, we have investigated collisional Penrose process (CPP) using spinning particles in a Kerr spacetime. Recent studies have shown that the collision between two spinning particles can produce a significantly high energy in the center of mass frame. Here, we explicitly compute the energy extraction and efficiency as measured by an observer at infinity. We consider the colliding particles as well as the escaping particles may contain spins. It has been shown that the energy extraction is larger than the non-spinning case and also their possibility to escape to infinity is wider than the geodesics.

Investigation of electro-optical properties of InSb under the influence of spin-orbit interaction at room temperature

Energy Technology Data Exchange (ETDEWEB)

Hilal, Muhammad; Rashid, Bahroz; Khan, Shah Haider; Khan, Afzal, E-mail: afzal_khan@upesh.edu.pk

2016-12-01

To investigate the electro-optical properties of indium antimonide (InSb) for photo-voltaic applications, we performed first principles calculations using density functional theory (DFT). Our DFT calculations are based on full potential linearized augmented plane wave (FP-LAPW) method implemented by WIEN2K code. These calculations are carried out using generalized gradient approximation (GGA) and Tran Blaha modified Becke Johnson (TB-mBJ) approximation for exchange co-relation potential. All the calculations are performed with and without the addition of spin-orbit interaction (SOI) to GGA and TB-mBJ potentials. Addition of SOI gives the results very close to their experimental values and makes the calculations independent of k-points consideration. All the results are calculated by considering the temperature as high as 300 K. To the best of our knowledge, all the previously published theoretical results were calculated at 0 K and no such results have been reported at 300 K. In this article, we are reporting band structure, density of states (DOS) and the band gap dependent optical properties of InSb. The calculated direct band gap is 0.17 eV, refractive index is 3.79 and extinction coefficient as 3.22. - Highlights: • Room temperature calculations of electro-optical properties of InSb. • Effect of SOI on the band structure and critical points. • The addition of SOI made the calculation k-points independent. • Optical properties were calculated without broadening or applying scissor potential.

Spin versus helicity in processes involving transversity

CERN Document Server

Mekhfi, Mustapha

2011-01-01

We construct the spin formalism in order to deal in a direct and natural way with processes involving transversity which are now of increasing popularity. The helicity formalism which is more appropriate for collision processes of definite helicity has been so far used also to manage processes with transversity, but at the price of computing numerous helicity amplitudes generally involving unnecessary kinematical variables.In a second step we work out the correspondence between both formalisms and retrieve in another way all results of the helicity formalism but in simpler forms.We then compute certain processes for comparison.A special process:the quark dipole magnetic moment is shown to be exclusively treated within the spin formalism as it is directly related to the transverse spin of the quark inside the baryon.

Latest HERMES results on transverse spin effects in hadron structure and formation

International Nuclear Information System (INIS)

Pappalardo, L.L.

2008-01-01

Transverse target single-spin asymmetries in semi-inclusive deep inelastic scattering allow to study the so-called Collins and Sivers mechanisms. The first one connects the poorly known fundamental transversity distribution function, describing the transverse spin-polarization of quarks in a transversely polarized proton, to the Collins fragmentation function, describing spin-orbit correlations in the hadron formation process. The second one is sensitive to the Sivers function, which correlates the intrinsic transverse momentum of quarks with the proton's spin orientation and is related to the orbital angular momentum of quarks. Preliminary results on azimuthal single target-spin asymmetries in semi-inclusive electro-production of pions and kaons at the HERMES experiment are presented. The full data set collected with a transversely polarized hydrogen target was analyzed providing the HERMES most precise results on the Collins and Sivers azimuthal moments. (orig.)

Spin-Dependent Processes Measured without a Permanent Magnet.

Science.gov (United States)

Fontanesi, Claudio; Capua, Eyal; Paltiel, Yossi; Waldeck, David H; Naaman, Ron

2018-05-07

A novel Hall circuit design that can be incorporated into a working electrode, which is used to probe spin-selective charge transfer and charge displacement processes, is reviewed herein. The general design of a Hall circuit based on a semiconductor heterostructure, which forms a shallow 2D electron gas and is used as an electrode, is described. Three different types of spin-selective processes have been studied with this device in the past: i) photoinduced charge exchange between quantum dots and the working electrode through chiral molecules is associated with spin polarization that creates a local magnetization and generates a Hall voltage; ii) charge polarization of chiral molecules by an applied voltage is accompanied by a spin polarization that generates a Hall voltage; and iii) cyclic voltammetry (current-voltage) measurements of electrochemical redox reactions that can be spin-analyzed by the Hall circuit to provide a third dimension (spin) in addition to the well-known current and voltage dimensions. The three studies reviewed open new doors into understanding both the spin current and the charge current in electronic materials and electrochemical processes. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Distributed quantum information processing via quantum dot spins

International Nuclear Information System (INIS)

Jun, Liu; Qiong, Wang; Le-Man, Kuang; Hao-Sheng, Zeng

2010-01-01

We propose a scheme to engineer a non-local two-qubit phase gate between two remote quantum-dot spins. Along with one-qubit local operations, one can in principal perform various types of distributed quantum information processing. The scheme employs a photon with linearly polarisation interacting one after the other with two remote quantum-dot spins in cavities. Due to the optical spin selection rule, the photon obtains a Faraday rotation after the interaction process. By measuring the polarisation of the final output photon, a non-local two-qubit phase gate between the two remote quantum-dot spins is constituted. Our scheme may has very important applications in the distributed quantum information processing

Process parameter influence on Electro-sinter-forging (ESF) of titanium discs

DEFF Research Database (Denmark)

Cannella, Emanuele; Nielsen, Chris Valentin; Bay, Niels

Electro-sinter-forging (ESF) is a sintering process based on the resistance heating principle, which makes it faster than conventional sintering. The process is investigated as a function of the main process parameters, namely compacting pressure, electrical current density and sintering time....... The present work is focused on analysing the influence of these process parameters on the final density of a disc sample made from commercially pure titanium powder. Applying the design of experiments (DoE) approach, the electrical current was seen to be of largest influence. The maximum obtained density...

Verifying business processes using spin

NARCIS (Netherlands)

Janssen, W.; Mateescu, R.; Mauw, S.; Springintveld, J.; Holzmann, G.; Najm, E.; Serhrouchni, A.

1998-01-01

We present an application of the Spin model-checker in Testbed, a framework for business process reengineering. Business processes are described by end-users of Testbed in a graphi- cal language with a causality-based semantics, called Amber. The Amber language contains various constructs describing

Comparative study on the removal of COD from POME by electrocoagulation and electro-Fenton methods: Process optimization

Science.gov (United States)

Chairunnisak, A.; Arifin, B.; Sofyan, H.; Lubis, M. R.; Darmadi

2018-03-01

This research focuses on the Chemical Oxygen Demand (COD) treatment in palm oil mill effluent by electrocoagulation and electro-Fenton methods to solve it. Initially, the aqueous solution precipitates in acid condition at pH of about two. This study focuses on the palm oil mill effluent degradation by Fe electrodes in a simple batch reactor. This work is conducted by using different parameters such as voltage, electrolyte concentration of NaCl, volume of H2O2 and operation time. The processing of data resulted is by using response surface method coupled with Box-Behnken design. The electrocoagulation method results in the optimum COD reduction of 94.53% from operating time of 39.28 minutes, 20 volts, and without electrolyte concentration. For electro-Fenton process, experiment points out that voltage 15.78 volts, electrolyte concentration 0.06 M and H2O2 volume 14.79 ml with time 35.92 minutes yield 99.56% degradation. The result concluded that the electro-Fenton process was more effective to degrade COD of the palm-oil-mill effluent compared to electrocoagulation process.

Electro spinning of Poly(ethylene-co-vinyl alcohol) Nano fibres Encapsulated with Ag Nanoparticles for Skin Wound Healing

International Nuclear Information System (INIS)

Xu, Ch.; Wang, B.; Lu, T.; Xu, F.; Xu, F.; Wang, B.; Xu, F.

2011-01-01

Skin wound healing is an urgent problem in clinics and military activities. Although significant advances have been made in its treatment, there are several challenges associated with traditional methods, for example, limited donor skin tissue for transplantation and inflammation during long-term healing time. To address these challenges, in this study we present a method to fabricate Poly(ethylene-co-vinyl alcohol) (EVOH) nano fibres encapsulated with Ag nanoparticle using electro spinning technique. The fibres were fabricated with controlled diameters (59 nm 3μm) by regulating three main parameters, that is, EVOH solution concentration, the electric voltage, and the distance between the injection needle tip (high-voltage point) and the fibre collector. Ag was added to the nano fibres to offer long-term anti-inflammation effect by slow release of Ag nanoparticles through gradual degradation of EVOH nano fibre. The method developed here could lead to new dressing materials for treatment of skin wounds.

One and two-phonon processes of the spin-flip relaxation in quantum dots: Spin-phonon coupling mechanism

Science.gov (United States)

Wang, Zi-Wu; Li, Shu-Shen

2012-07-01

We investigate the spin-flip relaxation in quantum dots using a non-radiation transition approach based on the descriptions for the electron-phonon deformation potential and Fröhlich interaction in the Pavlov-Firsov spin-phonon Hamiltonian. We give the comparisons of the electron relaxations with and without spin-flip assisted by one and two-phonon processes. Calculations are performed for the dependence of the relaxation time on the external magnetic field, the temperature and the energy separation between the Zeeman sublevels of the ground and first-excited state. We find that the electron relaxation time of the spin-flip process is more longer by three orders of magnitudes than that of no spin-flip process.

Application of Electro-Technologies in Processing of Flax Fiber

Directory of Open Access Journals (Sweden)

G. S. Vijaya Raghavan

2013-08-01

Full Text Available Flax fibers used for various applications are obtained from flax stems. Retting followed by drying and mechanical separation leads to the production of fibers. This review article discusses the application of electro-technologies in the production of bast fibers from the flax stem. In these technologies, flax stems harvested from the field are subjected to microwave assisted retting, followed by electro–osmotic dewatering which reduces the water content of the stems. Dewatered stems are transferred to a microwave chamber for further drying, thus retted stems are obtained for further processing.

Perspectives of using spin waves for computing and signal processing

Energy Technology Data Exchange (ETDEWEB)

Csaba, György, E-mail: gcsaba@gmail.com [Center for Nano Science and Technology, University of Notre Dame (United States); Faculty for Information Technology and Bionics, Pázmány Péter Catholic University (Hungary); Papp, Ádám [Center for Nano Science and Technology, University of Notre Dame (United States); Faculty for Information Technology and Bionics, Pázmány Péter Catholic University (Hungary); Porod, Wolfgang [Center for Nano Science and Technology, University of Notre Dame (United States)

2017-05-03

Highlights: • We give an overview of spin wave-based computing with emphasis on non-Boolean signal processors. • Spin waves can combine the best of electronics and photonics and do it in an on-chip and integrable way. • Copying successful approaches from microelectronics may not be the best way toward spin-wave based computing. • Practical devices can be constructed by minimizing the number of required magneto-electric interconnections. - Abstract: Almost all the world's information is processed and transmitted by either electric currents or photons. Now they may get a serious contender: spin-wave-based devices may just perform some information-processing tasks in a lot more efficient and practical way. In this article, we give an engineering perspective of the potential of spin-wave-based devices. After reviewing various flavors for spin-wave-based processing devices, we argue that the niche for spin-wave-based devices is low-power, compact and high-speed signal-processing devices, where most traditional electronics show poor performance.

Multi-dimensional electro-omosis consolidation of clays

NARCIS (Netherlands)

Yuan, J.; Hicks, M.A.; Dijkstra, J.

2012-01-01

Electro-osmosis consolidation is an innovative and effective ground improvement method for soft clays. But electro-osmosis is also a very complicated process, as the mechanical behaviour, and hydraulic and electrical properties of the soil are changing rapidly during the treatment process; this

Large spin accumulation due to spin-charge coupling across a break-junction

Science.gov (United States)

Chen, Shuhan; Zou, Han; Chui, Siu-Tat; Ji, Yi

2013-03-01

We investigate large spin signals in break-junction nonlocal spin valves (NLSV). The break-junction is a nanometer-sized vacuum tunneling gap between the spin detector and the nonmagnetic channel, formed by electro-static discharge. The spin signals can be either inverted or non-inverted and the magnitudes are much larger than those of standard NLSV. Spin signals with high percentage values (10% - 0%) have been observed. When the frequency of the a.c. modulation is varied, the absolute magnitudes of signals remain the same although the percentage values change. These observations affirm the nonlocal nature of the measurements and rule out local magnetoresistive effects. Owing to the spin-charge coupling across the break-junction, the spin accumulation in a ferromagnet splits into two terms. One term decays on the charge screening length (0.1 nm) and the other decays on the spin diffusion length (10 nm nm). The magnitude of the former is proportional to the resistance of the junction. Therefore a highly resistive break-junction leads to a large spin accumulation and thereby a large spin signal. The signs of the spin signal are determined by the relationship between spin-dependent conductivities, diffusion constants, and density of states of the ferromagnet. This work was supported by US DOE grant No. DE-FG02-07ER46374.

Chromic acid recovery by electro-electrodialysis. II. Pilot scal process, development, and optimization

NARCIS (Netherlands)

Frenzel, I.; Frenzel, I.; Holdik, H.; Stamatialis, Dimitrios; Pourcelly, G.; Wessling, Matthias

2005-01-01

Electro-electrodialysis is a promising technology for chromic acid recovery and static rinse water purification. It combines the recovery of the plating chemicals from rinse water, the elimination of metallic impurities from the process and rinse water treatment in one step. Previous industrial use

Removal of macro-pollutants in oily wastewater obtained from soil remediation plant using electro-oxidation process.

Science.gov (United States)

Zolfaghari, Mehdi; Drogui, Patrick; Blais, Jean François

2018-03-01

Electro-oxidation process by niobium boron-doped diamond (Nb/BDD) electrode was used to treat non-biodegradable oily wastewater provided from soil leachate contaminated by hydrocarbons. Firstly, the diffusion current limit and mass transfer coefficient was experimentally measured (7.1 mA cm -2 and 14.7 μm s -1 , respectively), in order to understand minimum applied current density. Later on, the oxidation kinetic model of each pollutant was investigated in different current densities ranged between 3.8 and 61.5 mA cm -2 . It was observed that direct oxidation was the main removal mechanism of organic and inorganic carbon, while the indirect oxidation in higher current density was responsible for nitrogen oxidation. Hydrocarbon in the form of colloidal particles could be removed by electro-flotation. On the other hand, electro-decomposition on the surface of cathode and precipitation by hydroxyl ions were the utmost removal pathway of metals. According to the initial experiments, operating condition was further optimized by central composite design model in different current density, treatment time, and electrolyte addition, based on the best responses on the specific energy consumption (SEC), chemical oxygen demand (COD), and total organic carbon (TOC) removal efficiency. Unde r optimum operating condition (current density = 23.1 mA cm -2 , time = 120 min, Ti/Pt as a cathode, and Nb/BDD as the anode), electro-oxidation showed the following removal efficiencies: COD (84.6%), TOC (68.2%), oil and grease (99%), color (87.9%), total alkalinity (92%), N tot (18%), NH 4 + (31%), Ca (66.4%), Fe (71.1%), Mg (41.4%), Mn (78.1%), P tot (75%), S (67.1%), and Si (19.1%). Graphical abstract Environmental significance statement Soil treatment facilities are rapidly grown throughout the world, especially in North America due to its intense industrialization. High water content soil in humid area like Canada produces significant amount of leachate which is

Development of novel tungsten processing technologies for electro-chemical machining (ECM) of plasma facing components

International Nuclear Information System (INIS)

Holstein, Nils; Krauss, Wolfgang; Konys, Juergen

2011-01-01

Plasma facing components for fusion applications must exhibit long-term stability under extreme conditions, and therefore material imperfections cannot be tolerated due to a high risk of technical failures. To prevent or abolish defects in refractory metals components during the manufacturing process, some methods of electro-chemical machining as S-ECM and C-ECM were developed, enabling both the processing of smooth plain defect-free surfaces of different geometry and the removal of bulk material for the shaping of three-dimensional structures, also without cracks. It is discussed, that tungsten ablation with accurate electro-chemical molding is very sensitive to the kind of electric current, and therefore current investigations focused also on the effects of frequency profiles on the sharpness of edge rounding.

Electro-spray deposition of a mesoporous TiO2 charge collection layer: toward large scale and continuous production of high efficiency perovskite solar cells.

Science.gov (United States)

Kim, Min-cheol; Kim, Byeong Jo; Yoon, Jungjin; Lee, Jin-wook; Suh, Dongchul; Park, Nam-gyu; Choi, Mansoo; Jung, Hyun Suk

2015-12-28

The spin-coating method, which is widely used for thin film device fabrication, is incapable of large-area deposition or being performed continuously. In perovskite hybrid solar cells using CH(3)NH(3)PbI(3) (MAPbI(3)), large-area deposition is essential for their potential use in mass production. Prior to replacing all the spin-coating process for fabrication of perovskite solar cells, herein, a mesoporous TiO(2) electron-collection layer is fabricated by using the electro-spray deposition (ESD) system. Moreover, impedance spectroscopy and transient photocurrent and photovoltage measurements reveal that the electro-sprayed mesoscopic TiO(2) film facilitates charge collection from the perovskite. The series resistance of the perovskite solar cell is also reduced owing to the highly porous nature of, and the low density of point defects in, the film. An optimized power conversion efficiency of 15.11% is achieved under an illumination of 1 sun; this efficiency is higher than that (13.67%) of the perovskite solar cell with the conventional spin-coated TiO(2) films. Furthermore, the large-area coating capability of the ESD process is verified through the coating of uniform 10 × 10 cm(2) TiO(2) films. This study clearly shows that ESD constitutes therefore a viable alternative for the fabrication of high-throughput, large-area perovskite solar cells.

Spin-flip processes in low-energy Fe17+ + He collisions

International Nuclear Information System (INIS)

Bruch, R.; Altick, P.L.; Rauscher, E.; Wang, H.; Schneider, D.

1993-01-01

Spin-nonconserving electron transfer processes violating the ''Wigner rule'' have been studied for slow multiply charged ion-atom collisions. Experimentally a strong population of highly metastable sodium-like quartet states in low energy Fe 17+ + He single collision events has been observed. The possibility of double-electron capture plus spin-flip mechanisms has been discussed experimentally and theoretically, Our theoretical model using time dependent perturbation theory predicts that spin-flip processes are as likely as no spin flip under the conditions of our experiment

Influence of process operating parameters on dryness level and energy saving during wastewater sludge electro-dewatering.

Science.gov (United States)

Mahmoud, Akrama; Hoadley, Andrew F A; Conrardy, Jean-Baptiste; Olivier, Jérémy; Vaxelaire, Jean

2016-10-15

Electrically assisted mechanical dewatering, known as electro-dewatering (EDW), is an alternative emerging technology for energy-efficient liquid/solids separation in the dewatering of wastewater sludge. In this study, the performance of the electro-dewatering (EDW) process for activated wastewater sludge was investigated. The influence of the operating modes; being the timing of voltage (U-EDW) or current (I-EDW) application to either or both the filtration and compression stages, and the influence of the applied pressure (in successive 30 min pressure steps) were studied. The results showed that by delaying the application of the electric field to the filter cake compression stage, there was a potential saving in power consumption of around 10-12% in the case of U-EDW and about 30-46% in the case of I-EDW. The increase of the applied pressure from 0.5 to 12 bar during the filter cake compression stage leads to an increase in electro-dewatering kinetics. The results also reveal that at a low electric field level the increase of the processing pressure has a relatively pronounced effect on the dewatering process. At high levels of the electric field, a minimum processing pressure (4-6 bar) is required to improve the electrical contact between the electrode and the sludge and thus lower the energy consumption. Copyright © 2016 Elsevier Ltd. All rights reserved.

An Analysis and Modelling of Spinning Process without Wall-Thickness Reduction

Directory of Open Access Journals (Sweden)

Jurković, M.

2006-01-01

Full Text Available Through the spinning process it is made the different axial-symmetrical parts by acting spinning roller on blank of sheet metal, which is shaped through a chuck. In the paper is shown an analyse of stressed and strained state, as well as forming force components of spinning process. On the ground of experimental results it is made mathematical modelling of spinning forming force. The obtained mathematical model describes enough accurate and reliable (P = 0,98 the spinning forming force.

Medically relevant ElectroNeedle technology development.

Energy Technology Data Exchange (ETDEWEB)

Schmidt, Carrie Frances; Thomas, Michael Loren; McClain, Jaime L.; Harper, Jason C.; Achyuthan, Komandoor E.; Ten Eyck, Gregory A.

2008-11-01

ElectroNeedles technology was developed as part of an earlier Grand Challenge effort on Bio-Micro Fuel Cell project. During this earlier work, the fabrication of the ElectroNeedles was accomplished along with proof-of-concept work on several electrochemically active analytes such as glucose, quinone and ferricyanide. Additionally, earlier work demonstrated technology potential in the field of immunosensors by specifically detecting Troponin, a cardiac biomarker. The current work focused upon fabrication process reproducibility of the ElectroNeedles and then using the devices to sensitively detect p-cresol, a biomarker for kidney failure or nephrotoxicity. Valuable lessons were learned regarding fabrication assurance and quality. The detection of p-cresol was accomplished by electrochemistry as well as using fluorescence to benchmark ElectroNeedles performance. Results from these studies will serve as a guide for the future fabrication processes involving ElectroNeedles as well as provide the groundwork necessary to expand technology applications. One paper has been accepted for publication acknowledging LDRD funding (K. E. Achyuthan et al, Comb. Chem. & HTS, 2008). We are exploring the scope for a second paper describing the applications potential of this technology.

Activated sludge treatment by electro-Fenton process: Parameter optimization and degradation mechanism

Energy Technology Data Exchange (ETDEWEB)

Rahmani, Ali Reza; Azarian, Ghasem; Berizi, Zohreh [Hamadan University of Medical Sciences, Hamadan (Iran, Islamic Republic of); Nematollahi, Davood [Bu-Ali-Sina University, Hamadan (Iran, Islamic Republic of); Godini, Kazem [Ilam University of Medical Sciences, Ilam (Iran, Islamic Republic of)

2015-08-15

This study was conducted to evaluate the mineralization of activated sludge (MAS) by a facile and environmentally friendly electro-Fenton process (EFP). The effects of initial H{sub 2}O{sub 2} concentration, pH value, applied current density and operating time on MAS through determining the removal rate of chemical oxygen demand (COD) and total coliform (TC) were studied. 72% of COD was removed by indirect oxidation double-mediated based on the electro- generation of hydroxyl radical and active chlorine, under the following optimum conditions: 127mmol L{sup -}1 of hydrogen peroxide, pH=3.0, 10 mA cm{sup -}2 of DC current, 120min of operating time, and 0.22mol L{sup -}1 of NaCl as the supporting electrolyte. Only in 10 min and pH 3.0 approximately 100% of TC was removed. The findings indicated that EFP can be applied efficiently for MAS by selecting appropriate operating conditions. The bottom line is that the process is entirely effective owing to the application of green oxidants (hydroxyl radical and active chlorine) and lack of being influenced by environmental situations, which can be introduced as an alternative to current conventional methods.

Activated sludge treatment by electro-Fenton process: Parameter optimization and degradation mechanism

International Nuclear Information System (INIS)

Rahmani, Ali Reza; Azarian, Ghasem; Berizi, Zohreh; Nematollahi, Davood; Godini, Kazem

2015-01-01

This study was conducted to evaluate the mineralization of activated sludge (MAS) by a facile and environmentally friendly electro-Fenton process (EFP). The effects of initial H 2 O 2 concentration, pH value, applied current density and operating time on MAS through determining the removal rate of chemical oxygen demand (COD) and total coliform (TC) were studied. 72% of COD was removed by indirect oxidation double-mediated based on the electro- generation of hydroxyl radical and active chlorine, under the following optimum conditions: 127mmol L - 1 of hydrogen peroxide, pH=3.0, 10 mA cm - 2 of DC current, 120min of operating time, and 0.22mol L - 1 of NaCl as the supporting electrolyte. Only in 10 min and pH 3.0 approximately 100% of TC was removed. The findings indicated that EFP can be applied efficiently for MAS by selecting appropriate operating conditions. The bottom line is that the process is entirely effective owing to the application of green oxidants (hydroxyl radical and active chlorine) and lack of being influenced by environmental situations, which can be introduced as an alternative to current conventional methods.

Notes on Process and Data Analysis in Electro-Coagulation—The Importance of Standardisation and Clarity.

Czech Academy of Sciences Publication Activity Database

Tito, Duarte Novaes; Krystyník, Pavel; Klusoň, Petr

2016-01-01

Roč. 104, JUN 2016 (2016), s. 22-28 ISSN 0255-2701 Institutional support: RVO:67985858 Keywords : electro-coagulation * water treatment * process efficacy Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.234, year: 2016

Vanishing current hysteresis under competing nuclear spin pumping processes in a quadruplet spin-blockaded double quantum dot

Energy Technology Data Exchange (ETDEWEB)

Amaha, S., E-mail: s-amaha@riken.jp [Quantum Spin Information Project, Japan Science and Technology Agency, ICORP, 3-1, Morinosato Wakamiya, Atsugi-shi, Kanagawa 243-0198 (Japan); Quantum Functional System Research Group, RIKEN Center for Emergent Matter Science, RIKEN, 3-1 Wako-shi, Saitama 351-0198 (Japan); Hatano, T. [Quantum Spin Information Project, Japan Science and Technology Agency, ICORP, 3-1, Morinosato Wakamiya, Atsugi-shi, Kanagawa 243-0198 (Japan); Department of Physics, Tohoku University, Sendai-shi, Miyagi 980-8578 (Japan); Tarucha, S. [Quantum Spin Information Project, Japan Science and Technology Agency, ICORP, 3-1, Morinosato Wakamiya, Atsugi-shi, Kanagawa 243-0198 (Japan); Quantum Functional System Research Group, RIKEN Center for Emergent Matter Science, RIKEN, 3-1 Wako-shi, Saitama 351-0198 (Japan); Department of Applied Physics, School of Engineering, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Gupta, J. A.; Austing, D. G. [National Research Council of Canada, M50, Montreal Road, Ottawa, Ontario K1A 0R6 (Canada)

2015-04-27

We investigate nuclear spin pumping with five-electron quadruplet spin states in a spin-blockaded weakly coupled vertical double quantum dot device. Two types of hysteretic steps in the leakage current are observed on sweeping the magnetic field and are associated with bidirectional polarization of nuclear spin. Properties of the steps are understood in terms of bias-voltage-dependent conditions for the mixing of quadruplet and doublet spin states by the hyperfine interaction. The hysteretic steps vanish when up- and down-nuclear spin pumping processes are in close competition.

Spin structure of nucleon in QCD: inclusive and exclusive processes

International Nuclear Information System (INIS)

Teryaev, O.V.

2001-01-01

There are two basically independent ways to describe the nucleon spin structure. One is related to quark and gluon spins and another one to their total angular momenta. The latter spin structure may be studied, in principle, in hard exclusive processes

Electro-chemically-based technologies for processing of tungsten components in fusion technology

International Nuclear Information System (INIS)

Holstein, N.; Konys, J.; Krauss, W.; Lorenz, J.

2010-01-01

In fusion technology layers and bulk components fabricated from tungsten and W-alloys are used as functional materials, e.g. as coatings of blanket modules or T-permeation barriers and also as structural components in a He-cooled divertor. Their application under high heat loads and temperatures is besides manufacturing, also challenging regarding joining, caused e.g. by expansion mismatches in combination with steel or other diffusion issues. Driven by these needs, electro-chemically-based technologies were analyzed concerning their advantages in processing in the fields of soft structuring of tungsten alloys and in deposition of functional scales. The Electro-Chemistry (EC) of tungsten is characterized by its affection to build up passivation layers in aqueous media during the initial oxidation, which is the result of an unavoidable basic electrochemical reaction with water (W + 3H 2 O → WO 3 + 3H 2 ), although the element standard potential is situated between common EC material like iron and copper. (orig.)

Ultrafast spin exchange-coupling torque via photo-excited charge-transfer processes

Science.gov (United States)

Ma, X.; Fang, F.; Li, Q.; Zhu, J.; Yang, Y.; Wu, Y. Z.; Zhao, H. B.; Lüpke, G.

2015-10-01

Optical control of spin is of central importance in the research of ultrafast spintronic devices utilizing spin dynamics at short time scales. Recently developed optical approaches such as ultrafast demagnetization, spin-transfer and spin-orbit torques open new pathways to manipulate spin through its interaction with photon, orbit, charge or phonon. However, these processes are limited by either the long thermal recovery time or the low-temperature requirement. Here we experimentally demonstrate ultrafast coherent spin precession via optical charge-transfer processes in the exchange-coupled Fe/CoO system at room temperature. The efficiency of spin precession excitation is significantly higher and the recovery time of the exchange-coupling torque is much shorter than for the demagnetization procedure, which is desirable for fast switching. The exchange coupling is a key issue in spin valves and tunnelling junctions, and hence our findings will help promote the development of exchange-coupled device concepts for ultrafast coherent spin manipulation.

Modeling the neutron spin-flip process in a time-of-flight spin-resonance energy filter

CERN Document Server

Parizzi, A A; Klose, F

2002-01-01

A computer program for modeling the neutron spin-flip process in a novel time-of-flight (TOF) spin-resonance energy filter has been developed. The software allows studying the applicability of the device in various areas of spallation neutron scattering instrumentation, for example as a dynamic TOF monochromator. The program uses a quantum-mechanical approach to calculate the local spin-dependent spectra and is essential for optimizing the magnetic field profiles along the resonator axis. (orig.)

Study of the removal of metronidazole from aqueous solutions using Electro/ Fenton process and graphite and iron electrodes

Directory of Open Access Journals (Sweden)

Bahram Kamarehie

2018-04-01

Conclusion: The Electro-Fenton process can effectively remove metronidazole from aquatic solutions in environmentally convenient conditions. This process can be used as an efficient method for removing other persistent pollutants from the environment.

Evaluation of the sensitivity of electro-acoustic measurements for process monitoring and control of an atmospheric pressure plasma jet system

Energy Technology Data Exchange (ETDEWEB)

Law, V J [Dublin City University, National Centre of Plasma Science and Technology, Collins Avenue, Glasnevin, Dublin 9, Dublin (Ireland); O' Neill, F T; Dowling, D P, E-mail: vic.law@dcu.ie [School Mechanical and Materials Engineering, University College Dublin, Belfield, Dublin 4 (Ireland)

2011-06-15

The development of non-invasive process diagnostic techniques for the control of atmospheric plasmas is a critical issue for the wider adoption of this technology. This paper evaluates the use of a frequency-domain deconvolution of an electro-acoustic emission as a means to monitor and control the plasma formed using an atmospheric pressure plasma jet (APPJ) system. The air plasma system investigated was formed using a PlasmaTreat(TM) OpenAir applicator. Change was observed in the electro-acoustic signal with changes in substrate type (ceramic, steel, polymer). APPJ nozzle to substrate distance and substrate feature size were monitored. The decoding of the electro-acoustic emission yields three subdatasets that are described by three separate emission mechanisms. The three emissions are associated with the power supply fundamental drive frequency and its harmonics, the APPJ nozzle longitudinal mode acoustic emission and its odd overtones, and the acoustic surface reflection that is produced by the impedance mismatch between the discharge and the surface. Incorporating this knowledge into a LabVIEW program facilitated the continuous deconvolution of the electro-acoustic data. This enabled the use of specific frequency band test limits to control the APPJ treatment process which is sensitive to both plasma processing conditions and substrate type and features.

p-Nitrophenol degradation by electro-Fenton process: Pathway, kinetic model and optimization using central composite design.

Science.gov (United States)

Meijide, J; Rosales, E; Pazos, M; Sanromán, M A

2017-10-01

The chemical process scale-up, from lab studies to industrial production, is challenging and requires deep knowledge of the kinetic model and the reactions that take place in the system. This knowledge is also useful in order to be employed for the reactor design and the determination of the optimal operational conditions. In this study, a model substituted phenol such as p-nitrophenol was degraded by electro-Fenton process and the reaction products yielded along the treatment were recorded. The kinetic model was developed using Matlab software and was based on main reactions that occurred until total mineralization which allowed predicting the degradation pathway under this advanced oxidation process. The predicted concentration profiles of p-nitrophenol, their intermediates and by-products in electro-Fenton process were validated with experimental assays and the results were consistent. Finally, based on the developed kinetic model the degradation process was optimized using central composite design taking as key parameters the ferrous ion concentration and current density. Copyright © 2017 Elsevier Ltd. All rights reserved.

Enhanced methanol electro-oxidation reaction on Pt-CoOx/MWCNTs hybrid electro-catalyst

International Nuclear Information System (INIS)

Nouralishahi, Amideddin; Rashidi, Ali Morad; Mortazavi, Yadollah; Khodadadi, Abbas Ali; Choolaei, Mohammadmehdi

2015-01-01

Highlights: • Promoting effects of Cobalt oxide on methanol electro-oxidation over Pt/MWCNTs are investigated. • Higher activity, about 2.9 times, and enhanced stability are observed on Pt-CoO x /MWCNTs. • Electrochemical active surface area of Pt nanoparticles is significantly improved upon CoO x addition. • Bi-functional mechanism is facilitated in presence of CoO x . - Abstract: The electro-catalytic behavior of Pt-CoO x /MWCNTs in methanol electro-oxidation reaction (MOR) is investigated and compared to that of Pt/MWCNTs. The electro-catalysts were synthesized by an impregnation method using NaBH 4  as the reducing agent. The morphological and physical characteristics of samples are examined by XRD, TEM, ICP and EDS techniques. In the presence of CoO x , Pt nanoparticles were highly distributed on the support with an average particle size of 2 nm, an obvious decrease from 5.1 nm for Pt/MWCNTs. Cyclic voltammetry, CO-stripping, Chronoamperometry, and electrochemical impedance spectroscopy (EIS) measurements are used to study the electrochemical behavior of the electro-catalysts. The results revealed a considerable enhancement in the oxidation kinetics of CO ads on Pt active sites by the participation of CoO x . Compared to Pt/MWCNTs, Pt-CoO x /MWCNTs sample has a larger electrochemical active surface area (ECSA) and higher electro-catalytic activity and stability toward methanol electro-oxidation. According to the results of cyclic voltammetry, the forward anodic peak current density enhances more than 89% at the optimum atomic ratio of Pt:Co = 2:1. Furthermore, inclusion of cobalt oxide species causes the onset potential of methanol electro-oxidation reaction to shift 84 mV to negative values compared to that on Pt/MWCNTs. Based on EIS data, dehydrogenation of methanol is the rate-determining step of MOR on both Pt/MWCNTs and Pt-CoO x /MWCNTs, at small overpotentials. However, at higher overpotentials, the oxidation of adsorbed oxygen-containing groups

Photoinduced electro-optics measurements of biosilica transformation to cristobalite

Energy Technology Data Exchange (ETDEWEB)

Fuchs, Ido [Department of Chemistry and the Institute of Nanotechnology, Bar-Ilan University, Ramat-Gan 52900 (Israel); Aluma, Yaniv; Ilan, Micha [Department of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801 (Israel); Kityk, Iwan [Institute of Electronic Systems, Faculty of Electrical Engineering, Czestochowa University, Czestochowa 42-201 (Poland); Mastai, Yitzhak, E-mail: Yitzhak.Mastai@biu.ac.il [Department of Chemistry and the Institute of Nanotechnology, Bar-Ilan University, Ramat-Gan 52900 (Israel)

2015-03-15

In this paper we studied the photoinduced electro optics effects in the thermal transformation process of biosilica to cristobalite, at a relatively low temperature and ambient pressure. This process was characterized by a variety of standards techniques with emphasis on linear electro optic effect measurements. Overall we demonstrated that photoinduced electro optics measurements are very sensitive to the transformation from amorphous structure of silica in the natural sponge samples to laminar string morphology of cristobalite. With this technique we could probe the change in the samples chirality from achiral bio silica to chiral cristobalite structure. Furthermore it is shown that natural biosilica have photoinduced linear electro optics respond indicating the chiral natural of biosilica. - Graphical abstract: The phase transformation of biosilica from marine sponges to Cristobalite under thermal treatment was investigated using photoinduced electro optics measurements. The figure shows the changes of the electro-optic coefficient of cristobalite and biosilica. - Highlights: • We examine phase transformation of biosilica. • We report transition from amorphous biosilica to crystalline Cristobalite. • Biosilica transformation to Cristobalite at temperature of 850 °C. • Biosilica transformation is studied with photoinduced measurements. • We examine changes in the photoinduced linear electro optics properties.

Photoinduced electro-optics measurements of biosilica transformation to cristobalite

International Nuclear Information System (INIS)

Fuchs, Ido; Aluma, Yaniv; Ilan, Micha; Kityk, Iwan; Mastai, Yitzhak

2015-01-01

In this paper we studied the photoinduced electro optics effects in the thermal transformation process of biosilica to cristobalite, at a relatively low temperature and ambient pressure. This process was characterized by a variety of standards techniques with emphasis on linear electro optic effect measurements. Overall we demonstrated that photoinduced electro optics measurements are very sensitive to the transformation from amorphous structure of silica in the natural sponge samples to laminar string morphology of cristobalite. With this technique we could probe the change in the samples chirality from achiral bio silica to chiral cristobalite structure. Furthermore it is shown that natural biosilica have photoinduced linear electro optics respond indicating the chiral natural of biosilica. - Graphical abstract: The phase transformation of biosilica from marine sponges to Cristobalite under thermal treatment was investigated using photoinduced electro optics measurements. The figure shows the changes of the electro-optic coefficient of cristobalite and biosilica. - Highlights: • We examine phase transformation of biosilica. • We report transition from amorphous biosilica to crystalline Cristobalite. • Biosilica transformation to Cristobalite at temperature of 850 °C. • Biosilica transformation is studied with photoinduced measurements. • We examine changes in the photoinduced linear electro optics properties

Spin physics and inclusive processes at short distances

International Nuclear Information System (INIS)

Craigie, N.S.

1982-10-01

The following aspects of spin physics at short distances are studied: 1. the factorization theorem in perturbative QCD and helicity asymmetries in inclusive processes, 2. the effect of higher order radiative corrections on helicity asymmetries, 3. the higher order power mechanism and spin asymmetries, 4. difficulties in understanding transverse spin in perturbative QCD, 5. helicity asymmetries of short distances as a means of recognizing supersymmetric interactions. Experiments are suggested for the verification of theoretical conclusions. Although spin-physics at short distances is difficult to demonstrate experimentally it may provide a valuable tool to show how perturbative QCD operates in the presence of the non-perturbative hadronic structure. It may also prove valuable to show new interactions which might occur at very short distances

Integration of adaptive process control with computational simulation for spin-forming

International Nuclear Information System (INIS)

Raboin, P. J. LLNL

1998-01-01

Improvements in spin-forming capabilities through upgrades to a metrology and machine control system and advances in numerical simulation techniques were studied in a two year project funded by Laboratory Directed Research and Development (LDRD) at Lawrence Livermore National Laboratory. Numerical analyses were benchmarked with spin-forming experiments and computational speeds increased sufficiently to now permit actual part forming simulations. Extensive modeling activities examined the simulation speeds and capabilities of several metal forming computer codes for modeling flat plate and cylindrical spin-forming geometries. Shape memory research created the first numerical model to describe this highly unusual deformation behavior in Uranium alloys. A spin-forming metrology assessment led to sensor and data acquisition improvements that will facilitate future process accuracy enhancements, such as a metrology frame. Finally, software improvements (SmartCAM) to the manufacturing process numerically integrate the part models to the spin-forming process and to computational simulations

Enhancement of oxygen diffusion process on a rotating disk electrode for the electro-Fenton degradation of tetracycline

International Nuclear Information System (INIS)

Zhang, Yan; Gao, Ming-Ming; Wang, Xin-Hua; Wang, Shu-Guang; Liu, Rui-Ting

2015-01-01

An electro-Fenton process was developed for wastewater treatment in which hydrogen peroxide was generated in situ with a rotating graphite disk electrode as cathode. The maximum H 2 O 2 generation rate for the RDE reached 0.90 mg/L/h/cm 2 under the rotation speed of 400 rpm at pH 3, and −0.8 V vs SCE. The performance of this electro-Fenton reactor was assessed by tetracycline degradation in an aqueous solution. Experimental results showed the rotation of disk cathode resulted in the efficient production of H 2 O 2 without oxygen aeration, and excellent ability for degrading organic pollutants compared to the electro-Fenton system with fixed cathode. Tetracycline of 50 mg/L was degraded completely within 2 h with the addition of ferrous ion (1.0 mM). The chronoamperometry analysis was employed to investigate the oxygen diffusion on the rotating cathode. The results demonstrated that the diffusion coefficients of dissolved oxygen is 19.45 × 10 −5 cm 2 /s, which is greater than that reported in the literature. Further calculation indicated that oxygen is able to diffuse through the film on the rotating cathode within the contact time in each circle. This study proves that enhancement of oxygen diffusion on RDE is benefit for H 2 O 2 generation, thus provides a promising method for organic pollutants degradation by the combination of RDE with electro-Fenton reactor and offers a new insight on the oxygen transform process in this new system.

Seed defective reduction in automotive Electro-Deposition Coating Process of truck cabin

Science.gov (United States)

Sonthilug, Aekkalag; Chutima, Parames

2018-02-01

The case study company is one of players in Thailand’s Automotive Industry who manufacturing truck and bus for both domestic and international market. This research focuses on a product quality problem about seed defects occurred in the Electro-Deposition Coating Process of truck cabin. The 5-phase of Six Sigma methodology including D-Define, M-Measure, A-Analyze, I-Improve, and C-Control is applied to this research to identify root causes of problem for setting new parameters of each significant factor. After the improvement, seed defects in this process is reduced from 9,178 defects per unit to 876 defects per unit (90% improvement)

Process parameter influence on Electro-sinter-forging (ESF) of titanium discs

DEFF Research Database (Denmark)

Cannella, Emanuele; Nielsen, Chris Valentin; Bay, Niels

Electro-sinter-forging (ESF) is an innovative sintering process based on the principle of electrical Joule heating. The electrical current is flowing through the powder compact, which is under mechanical pressure. As compared to conventional sintering [1] and spark plasma sintering [2], the main...... advantages are the decreased sintering time and high relative density [3]. Near net-shape components can be manufactured and post-removal processing is limited to surface polishing. The present work is focused on analysing the influence of the main process parameters, namely compacting pressure, sintering...... time and electrical current density, on the final density of a disc sample made from commercially pure titanium powder. The maximum achieved relative density was 94% of the bulk density of pure titanium. The density estimation was carried out by using both Archimedes’ and 3D scanning....

Compliant electro-thermal microactuators

DEFF Research Database (Denmark)

Jonsmann, Jacques; Sigmund, Ole; Bouwstra, Siebe

1999-01-01

This paper describes design, microfabrication and characterisation of topology optimised compliant electro-thermal microactuators. The actuators are fabricated by a fast prototyping process using laser micromachining and electroplating. Actuators are characterised with respect to displacement...

Information processing in patterned magnetic nanostructures with edge spin waves.

Science.gov (United States)

Lara, Antonio; Robledo Moreno, Javier; Guslienko, Konstantin Y; Aliev, Farkhad G

2017-07-17

Low dissipation data processing with spins is one of the promising directions for future information and communication technologies. Despite a significant progress, the available magnonic devices are not broadband yet and have restricted capabilities to redirect spin waves. Here we propose a breakthrough approach to spin wave manipulation in patterned magnetic nanostructures with unmatched characteristics, which exploits a spin wave analogue to edge waves propagating along a water-wall boundary. Using theory, micromagnetic simulations and experiment we investigate spin waves propagating along the edges in magnetic structures, under an in-plane DC magnetic field inclined with respect to the edge. The proposed edge spin waves overcome important challenges faced by previous technologies such as the manipulation of the spin wave propagation direction, and they substantially improve the capability of transmitting information at frequencies exceeding 10 GHz. The concept of the edge spin waves allows to design a broad of logic devices such as splitters, interferometers, or edge spin wave transistors with unprecedented characteristics and a potentially strong impact on information technologies.

Study of the Energy Conversion Process in the Electro-Hydrostatic Drive of a Vehicle

Directory of Open Access Journals (Sweden)

Wiesław Grzesikiewicz

2018-02-01

Full Text Available In the paper, we describe a study of an electro-hydrostatic hybrid drive of a utility van intended for city traffic. In this hybrid drive, the electric drive is periodically accompanied by hydrostatic drive, especially during acceleration and regenerative braking of the vehicle. We present a mathematical model of the hybrid drive as a set of dynamics and regulation equations of the van traveling at a given speed. On this basis, we construct a computer program which we use to simulate the processes of energy conversion in the electro-hydrostatic drive. The main goal of the numerical simulation is to assess the possibility of reducing energy intensity of the electric drive through such a support of the hydrostatic drive. The obtained results indicate that it is possible to reduce the load on elements of the electric system and, therefore, improve energy conversion.

Enhanced methanol electro-oxidation reaction on Pt-CoO{sub x}/MWCNTs hybrid electro-catalyst

Energy Technology Data Exchange (ETDEWEB)

Nouralishahi, Amideddin, E-mail: Nouralishahi@ut.ac.ir [Catalysis and Nanostructured Materials Research Laboratory, School of Chemical Engineering, University of Tehran, P.O. Box 11155/4563, Tehran (Iran, Islamic Republic of); Caspian Faculty of Engineering, University of Tehran, P.O. Box 43841-119, Rezvanshahr (Iran, Islamic Republic of); Catalysis and Nanotechnology Research Division, Research Institute of Petroleum Industry (RIPI), P.O. Box 14665-1998, Tehran (Iran, Islamic Republic of); Rashidi, Ali Morad, E-mail: Rashidiam@ripi.ir [Catalysis and Nanotechnology Research Division, Research Institute of Petroleum Industry (RIPI), P.O. Box 14665-1998, Tehran (Iran, Islamic Republic of); Mortazavi, Yadollah, E-mail: Mortazav@ut.ac.ir [Catalysis and Nanostructured Materials Research Laboratory, School of Chemical Engineering, University of Tehran, P.O. Box 11155/4563, Tehran (Iran, Islamic Republic of); Khodadadi, Abbas Ali, E-mail: Khodadad@ut.ac.ir [Catalysis and Nanostructured Materials Research Laboratory, School of Chemical Engineering, University of Tehran, P.O. Box 11155/4563, Tehran (Iran, Islamic Republic of); Choolaei, Mohammadmehdi, E-mail: Choolaeimm@ripi.ir [Catalysis and Nanotechnology Research Division, Research Institute of Petroleum Industry (RIPI), P.O. Box 14665-1998, Tehran (Iran, Islamic Republic of)

2015-04-30

Highlights: • Promoting effects of Cobalt oxide on methanol electro-oxidation over Pt/MWCNTs are investigated. • Higher activity, about 2.9 times, and enhanced stability are observed on Pt-CoO{sub x}/MWCNTs. • Electrochemical active surface area of Pt nanoparticles is significantly improved upon CoO{sub x} addition. • Bi-functional mechanism is facilitated in presence of CoO{sub x}. - Abstract: The electro-catalytic behavior of Pt-CoO{sub x}/MWCNTs in methanol electro-oxidation reaction (MOR) is investigated and compared to that of Pt/MWCNTs. The electro-catalysts were synthesized by an impregnation method using NaBH{sub 4} as the reducing agent. The morphological and physical characteristics of samples are examined by XRD, TEM, ICP and EDS techniques. In the presence of CoO{sub x}, Pt nanoparticles were highly distributed on the support with an average particle size of 2 nm, an obvious decrease from 5.1 nm for Pt/MWCNTs. Cyclic voltammetry, CO-stripping, Chronoamperometry, and electrochemical impedance spectroscopy (EIS) measurements are used to study the electrochemical behavior of the electro-catalysts. The results revealed a considerable enhancement in the oxidation kinetics of CO{sub ads} on Pt active sites by the participation of CoO{sub x}. Compared to Pt/MWCNTs, Pt-CoO{sub x}/MWCNTs sample has a larger electrochemical active surface area (ECSA) and higher electro-catalytic activity and stability toward methanol electro-oxidation. According to the results of cyclic voltammetry, the forward anodic peak current density enhances more than 89% at the optimum atomic ratio of Pt:Co = 2:1. Furthermore, inclusion of cobalt oxide species causes the onset potential of methanol electro-oxidation reaction to shift 84 mV to negative values compared to that on Pt/MWCNTs. Based on EIS data, dehydrogenation of methanol is the rate-determining step of MOR on both Pt/MWCNTs and Pt-CoO{sub x}/MWCNTs, at small overpotentials. However, at higher overpotentials, the

A linear dynamic model for rotor-spun composite yarn spinning process

International Nuclear Information System (INIS)

Yang, R H; Wang, S Y

2008-01-01

A linear dynamic model is established for the stable rotor-spun composite yarn spinning process. Approximate oscillating frequencies in the vertical and horizontal directions are obtained. By suitable choice of certain processing parameters, the mixture construction after the convergent point can be optimally matched. The presented study is expected to provide a general pathway to understand the motion of the rotor-spun composite yarn spinning process

Dynamics of chiral oscillations: a comparative analysis with spin flipping

International Nuclear Information System (INIS)

Bernardini, A E

2006-01-01

Chiral oscillation as well as spin flipping effects correspond to quantum phenomena of fundamental importance in the context of particle physics and, in particular, of neutrino physics. From the point of view of first quantized theories, we are specifically interested in pointing out the differences between chirality and helicity by obtaining their dynamic equations for a fermionic Dirac-type particle (neutrino). We also identify both effects when the non-minimal coupling with an external (electro)magnetic field in the neutrino interacting Lagrangian is taken into account. We demonstrate that, however, there is no constraint between chiral oscillations, when it takes place in vacuum, and the process of spin flipping related to the helicity quantum number, which does not take place in vacuum. To conclude, we show that the origin of chiral oscillations (in vacuum) can be interpreted as projections of very rapid oscillations of position onto the longitudinal direction of momentum

Electro-decontamination of cementitious materials

International Nuclear Information System (INIS)

Ben-Hadj-Hassine, S.

2012-01-01

The end of operations in nuclear facilities is followed by various decontamination and decommissioning operations. Similar to other electrochemical techniques such as re-alkalinisation and chloride extraction, an electrokinetic remediation process is being developed as a specific method for deeply contaminated concrete structures. Two cements, an ordinary Portland and a 30% slag cement, have been chosen for the conducted work.Mortars and concretes are contaminated by adding non-radioactive cesium in the batch water, cesium being a representative specie of deep encountered contaminants. The conducted experimental and numerical work have focused on three main aspects: characterizing and understanding the cesium transport mechanisms, assessing the electro-remediation process at lab-scale and evaluating the real scale constraints. Using existing knowledge of chloride transport mechanisms, experiments have been conducted to characterize the cesium interactions with cementitious phase and ionic transport in saturated materials. A numerical model have then been developed to describe the cesium transport, taking into account the ionic activity coefficients and interactions with solid phases. Indeed, lab-scale experiments have demonstrated that electro-remediation reduced to 20-50% the initially contained cesium after a three weeks treatment. Treated samples analysis confirmed that deeply diffused cesium is migrating to the surface. Moreover, conducted experiments showed the consistency between the different materials properties, applied currents and decontamination efficiency. A comparative analysis of experiments carried on samples with different shapes, formulations and contamination modes helped assessing and optimizing the process efficiency for various continuous and variable applied currents. Finally, electro-remediation experiments have also been carried on 1m 2 concrete slabs. Liquid catholyte and anolyte solutions are replaced by alumina gels and cellulose pastes

Electro photographic materials

International Nuclear Information System (INIS)

Buzdugan, A.; Andries, A.; Iovu, M.

2000-01-01

The invention relates to the creation of electro photographic materials . The invention allows to extend the material photosensitivity into the infrared range of the spectrum. An electro photographic materials contains an electro conducting base, including a dielectric base 1, for example glass, an electro conducting layer 2, for example of Al, Ni, Cr, an injecting layer 3, consisting of amorphous indium phosphide, a vitreous layer 4 of the arsenic sulphide - antimony sulphide system and a transporting layer 5 of the arsenic sulphide or arsenic selenide

Spin Current Noise of the Spin Seebeck Effect and Spin Pumping

Science.gov (United States)

Matsuo, M.; Ohnuma, Y.; Kato, T.; Maekawa, S.

2018-01-01

We theoretically investigate the fluctuation of a pure spin current induced by the spin Seebeck effect and spin pumping in a normal-metal-(NM-)ferromagnet(FM) bilayer system. Starting with a simple ferromagnet-insulator-(FI-)NM interface model with both spin-conserving and non-spin-conserving processes, we derive general expressions of the spin current and the spin-current noise at the interface within second-order perturbation of the FI-NM coupling strength, and estimate them for a yttrium-iron-garnet-platinum interface. We show that the spin-current noise can be used to determine the effective spin carried by a magnon modified by the non-spin-conserving process at the interface. In addition, we show that it provides information on the effective spin of a magnon, heating at the interface under spin pumping, and spin Hall angle of the NM.

Design and modelling of enzyme/poly-pyrrole modified electrodes for bio-catalyzed electro-synthesis processes

International Nuclear Information System (INIS)

Gros, Pierre

1996-01-01

This research thesis reports a study which aims at developing, analyzing and integrating an electrode-enzyme interface within an electro-enzymatic reactor to develop electrochemical biosensors. The adopted method comprises a confinement of the enzyme at the electrode surface by means of an electro-formed poly-pyrrole film. The author reports an experimental and theoretical study of the coupling between electrochemical reaction, enzymatic reaction and matter transfer in the polymer in order to better understand the operation of so-modified electrodes. Different parameters have an influence on the reaction rate. A numerical model (validated by experiments) allows the identification of the reaction limiting stages. A new elaboration protocol allows the polymer permeability to be increased. The interface is first applied to the reduction of the NAD coenzyme, and the process is also applied to the production of gluconic acid [fr

Control of electro-chemical processes using energy harvesting materials and devices.

Science.gov (United States)

Zhang, Yan; Xie, Mengying; Adamaki, Vana; Khanbareh, Hamideh; Bowen, Chris R

2017-12-11

Energy harvesting is a topic of intense interest that aims to convert ambient forms of energy such as mechanical motion, light and heat, which are otherwise wasted, into useful energy. In many cases the energy harvester or nanogenerator converts motion, heat or light into electrical energy, which is subsequently rectified and stored within capacitors for applications such as wireless and self-powered sensors or low-power electronics. This review covers the new and emerging area that aims to directly couple energy harvesting materials and devices with electro-chemical systems. The harvesting approaches to be covered include pyroelectric, piezoelectric, triboelectric, flexoelectric, thermoelectric and photovoltaic effects. These are used to influence a variety of electro-chemical systems such as applications related to water splitting, catalysis, corrosion protection, degradation of pollutants, disinfection of bacteria and material synthesis. Comparisons are made between the range harvesting approaches and the modes of operation are described. Future directions for the development of electro-chemical harvesting systems are highlighted and the potential for new applications and hybrid approaches are discussed.

A Multivariate Quality Loss Function Approach for Optimization of Spinning Processes

Science.gov (United States)

Chakraborty, Shankar; Mitra, Ankan

2018-05-01

Recent advancements in textile industry have given rise to several spinning techniques, such as ring spinning, rotor spinning etc., which can be used to produce a wide variety of textile apparels so as to fulfil the end requirements of the customers. To achieve the best out of these processes, they should be utilized at their optimal parametric settings. However, in presence of multiple yarn characteristics which are often conflicting in nature, it becomes a challenging task for the spinning industry personnel to identify the best parametric mix which would simultaneously optimize all the responses. Hence, in this paper, the applicability of a new systematic approach in the form of multivariate quality loss function technique is explored for optimizing multiple quality characteristics of yarns while identifying the ideal settings of two spinning processes. It is observed that this approach performs well against the other multi-objective optimization techniques, such as desirability function, distance function and mean squared error methods. With slight modifications in the upper and lower specification limits of the considered quality characteristics, and constraints of the non-linear optimization problem, it can be successfully applied to other processes in textile industry to determine their optimal parametric settings.

Pretreatment of furfural industrial wastewater by Fenton, electro-Fenton and Fe(II)-activated peroxydisulfate processes: a comparative study.

Science.gov (United States)

Yang, C W; Wang, D; Tang, Q

2014-01-01

The Fenton, electro-Fenton and Fe(II)-activated peroxydisulfate (PDS) processes have been applied for the treatment of actual furfural industrial wastewater in this paper. Through the comparative study of the three processes, a suitable pretreatment technology for actual furfural wastewater treatment was obtained, and the mechanism and dynamics process of this technology is discussed. The experimental results show that Fenton technology has a good and stable effect without adjusting pH of furfural wastewater. At optimal conditions, which were 40 mmol/L H₂O₂ initial concentration and 10 mmol/L Fe²⁺ initial concentration, the chemical oxygen demand (COD) removal rate can reach 81.2% after 90 min reaction at 80 °C temperature. The PDS process also has a good performance. The COD removal rate could attain 80.3% when Na₂S₂O₈ initial concentration was 4.2 mmol/L, Fe²⁺ initial concentration was 0.1 mol/L, the temperature remained at 70 °C, and pH value remained at 2.0. The electro-Fenton process was not competent to deal with the high-temperature furfural industrial wastewater and only 10.2% COD was degraded at 80 °C temperature in the optimal conditions (2.25 mA/cm² current density, 4 mg/L Na₂SO₄, 0.3 m³/h aeration rate). For the Fenton, electro-Fenton and PDS processes in pretreatment of furfural wastewater, their kinetic processes follow the pseudo first order kinetics law. The pretreatment pathways of furfural wastewater degradation are also investigated in this study. The results show that furfural and furan formic acid in furfural wastewater were preferentially degraded by Fenton technology. Furfural can be degraded into low-toxicity or nontoxic compounds by Fenton pretreatment technology, which could make furfural wastewater harmless and even reusable.

Muonium spin exchange in spin-polarized media: Spin-flip and -nonflip collisions

International Nuclear Information System (INIS)

Senba, M.

1994-01-01

The transverse relaxation of the muon spin in muonium due to electron spin exchange with a polarized spin-1/2 medium is investigated. Stochastic calculations, which assume that spin exchange is a Poisson process, are carried out for the case where the electron spin polarization of the medium is on the same axis as the applied field. Two precession signals of muonium observed in intermediate fields (B>30 G) are shown to have different relaxation rates which depend on the polarization of the medium. Furthermore, the precession frequencies are shifted by an amount which depends on the spin-nonflip rate. From the two relaxation rates and the frequency shift in intermediate fields, one can determine (i) the encounter rate of muonium and the paramagnetic species, (ii) the polarization of the medium, and most importantly (iii) the quantum-mechanical phase shift (and its sign) associated with the potential energy difference between electron singlet and triplet encounters. Effects of spin-nonflip collisions on spin dynamics are discussed for non-Poisson as well as Poisson processes. In unpolarized media, the time evolution of the muon spin in muonium is not influenced by spin-nonflip collisions, if the collision process is Poissonian. This seemingly obvious statement is not true anymore in non-Poissonian processes, i.e., it is necessary to specify both spin-flip and spin-nonflip rates to fully characterize spin dynamics

Scaled-up electrochemical reactor with a fixed bed three-dimensional cathode for electro-Fenton process: Application to the treatment of bisphenol A

International Nuclear Information System (INIS)

Chmayssem, Ayman; Taha, Samir; Hauchard, Didier

2017-01-01

In this study, we report on the development of an open undivided electrochemical reactor with a compact fixed bed of glassy carbon pellets as three-dimensional cathode for the application of electro-Fenton process. Bisphenol A (BPA) was chosen as model molecule in order to improve its efficiency to the treatment of persistent pollutants. The study of the BPA removal efficiency in function of the applied current intensity was investigated in order to determine the limiting current of O 2 reduction (optimal conditions of H 2 O 2 production at flow rate of 0.36 m 3 .h −1 ) which was 0.8 A (0.5 A/100 g of glassy carbon pellets). Many parameters have been carried out using this electro-Fenton reactor namely degradation kinetics, influence of anodic reactions on DSA, effect of initial pollutant concentration. In the optimal current condition, the global production rate of H 2 O 2 and ·OH was investigated. The yield of electro-Fenton reaction (conversion of H 2 O 2 to ·OH) was very high (> 90%). The absolute rate of BPA degradation was determined as 4.3 × 10 9 M −1 s −1 . COD, TOC and BOD 5 measurements indicated that only few minutes of treatment by electro-Fenton process were needed to eliminate BPA for dilute solutions (10 and 25 mg.L −1 ). In this case, the biodegradability of the treated solutions occurred rapidly. For higher concentration levels, an efficient removal of BPA appeared for treatment time higher than 1 hour and more than 90 minutes were necessary to obtain the biodegradability of BPA solutions. In optimum conditions, the scale-up of the electrochemical reactor applied to electro-Fenton process was suggested and depended on the concentration level of the pollutant. The operating parameters of the scaled-up reactor might be deduced from the new section of each fixed bed exposed to the flow, from values of liquid flow velocity and from the corresponding limiting current density obtained with the reactor at laboratory scale. The compact fixed bed

Optimisation of decolourisation and degradation of Reactive Black 5 dye under electro-Fenton process using Fe alginate gel beads.

Science.gov (United States)

Iglesias, O; Fernández de Dios, M A; Rosales, E; Pazos, M; Sanromán, M A

2013-04-01

The aim of this work was to improve the ability of the electro-Fenton process using Fe alginate gel beads for the remediation of wastewater contaminated with synthetic dyes and using a model diazo dye such as Reactive Black 5 (RB5). Batch experiments were conducted to study the effects of main parameters, such as voltage, pH and iron concentration. Dye decolourisation, reduction of chemical oxygen demand (COD) and energy consumption were studied. Central composite face-centred experimental design matrix and response surface methodology were applied to design the experiments and to evaluate the interactive effects of the three studied parameters. A total of 20 experimental runs were set, and the kinetic data were analysed using first-order and second-order models. In all cases, the experimental data were fitted to the empirical second-order model with a suitable degree for the maximum decolourisation of RB5, COD reduction and energy consumption by electro-Fenton-Fe alginate gel beads treatment. Working with the obtained empirical model, the optimisation of the process was carried out. The second-order polynomial regression model suggests that the optimum conditions for attaining maximum decolourisation, COD reduction and energy consumption are voltage, 5.69 V; pH 2.24 and iron concentration, 2.68 mM. Moreover, the fixation of iron on alginate beads suggests that the degradation process can be developed under this electro-Fenton process in repeated batches and in a continuous mode.

Electro-deposition painting process improvement of cab truck by Six Sigma concept

Science.gov (United States)

Kawitu, Kitiya; Chutima, Parames

2017-06-01

The case study company is a manufacturer of trucks and currently facing a high rework cost due to the thickness of the electro-deposited paint (EDP) of the truck cab is lower than standard. In addition, the process capability is very low. The Six Sigma concept consisting of 5 phases (DMAIC) is applied to determine new parameter settings for each significant controllable factor. After the improvement, EDP thickness of the truck cab increases from 17.88μ to 20μ (i.e. standard = 20 ± 3μ). Moreover, the process capability indexes (Cp and Cpk) are increased from 0.9 to 1.43, and from 0.27 to 1.43, respectively. This improvement could save the rework cost about 1.6M THB per year.

Application of electro-osmosis to radioactive waste processing

International Nuclear Information System (INIS)

Turner, A.D.

1989-01-01

Electro-osmotic dewatering (EOD) is a remotely controllable process for the final stage of slurry concentration after gravity settling or filtration prior to immobilization in cement. It operates by using an electric field instead of pressure as the driving force across a microporous non-conducting membrane - partitioning the solid and liquid components by charge separation. The high solids retention factor (> 99.99%) yields decontamination factors > 1000. Dewatering of a wide range of suspensions can be accomplished at a variety of membranes - including fabrics (eg cotton) for LLW, and ceramics or glass for MLW. Volume reduction factors of 10 can be achieved for low conductivity streams. Planar and tubular membrane designs have been considered for compact full-scale plants. Cost-benefit analyses indicate that, in common with other techniques, large savings on immobilization and disposal costs (> 87%) can be made by this further dewatering stage after gravity settling prior to cementing. Estimates for EOD of capital and running costs amount to 2% and 1.3% respectively of the savings made over 10 years, with electrical power contributing only 0.15%. (author)

Application of electro-technology in heating industrial processes; Aplicacion de electrotecnologia en procesos industriales de calentamiento

Energy Technology Data Exchange (ETDEWEB)

Gonzalez Milla, Guillermo [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)

2001-07-01

The electro-technologies are systems and equipment that use electricity to produce and to process consumer goods. Also they can be used in industrial processes such as drying, heating, heat treatment and smelting. These technologies have demonstrated that electricity can not only be used for lighting system, motor operation or electrolysis, but that can also be applied in many industrial processes and allow the reduction of production costs to increase the productivity as well as to improve the safety and conditions at work. Combined to the former, the electro technologies offer other additional advantages such as facilitating the automation, robotization and computerized supervision of industrial production. The great variety of these technologies and their ample application fields makes difficult a presentation of them showing their advantages in the energy efficiency field and with respect to the added value of the product to be finished, as well as its impact to the environment when diminishing the polluting agents to the atmosphere. The present article mentions diverse types of electro technologies, doing emphasis in those dedicated to provide heat impulse due to the impact that, by their application, can produce in the electrical system and to the deduction of polluting agents to the environment. Table 1 shows the diverse rank of industries that can use electro technologies. The table of the type of industries that can use electro technologies is shown, as well as the evaluation of these. [Spanish] Las electrotecnologias son sistemas y equipos que utilizan electricidad para producir y procesar bienes de consumo. Tambien pueden ser usados en procesos industriales tales como secado, calentamiento, tratamiento con calor y fundicion. Estas tecnologias han demostrado que la electricidad no solo se puede usar para alumbrado, alimentacion de motores o electrolisis, sino que puede aplicarse en muchos procesos industriales y permitir la reduccion de costos de

Systematic Procedure for Integrated Process Operation: Reverse Electro-Enhanced Dialysis (REED) during Lactic Acid Fermentation

DEFF Research Database (Denmark)

Prado Rubio, Oscar Andres; Jørgensen, Sten Bay; Jonsson, Gunnar Eigil

2011-01-01

The integration of lactic acid fermentation and Reverse Electro-Enhanced Dialysis (REED) is investigated based upon previously developed mathematical models. A goal driven process and operation design procedure is proposed and partially investigated. The conceptual analysis of the processes...... integration shows the need for an additional pH controller in the fermenten A PI controller is implemented and tested. The complete control structure for the integrated system consists of this PI controller in the fermenter plus a previously developed (Prado-Rubio et al., 2010) input resetting control...

Controllability of symmetric spin networks

Science.gov (United States)

Albertini, Francesca; D'Alessandro, Domenico

2018-05-01

We consider a network of n spin 1/2 systems which are pairwise interacting via Ising interaction and are controlled by the same electro-magnetic control field. Such a system presents symmetries since the Hamiltonian is unchanged if we permute two spins. This prevents full (operator) controllability, in that not every unitary evolution can be obtained. We prove however that controllability is verified if we restrict ourselves to unitary evolutions which preserve the above permutation invariance. For low dimensional cases, n = 2 and n = 3, we provide an analysis of the Lie group of available evolutions and give explicit control laws to transfer between two arbitrary permutation invariant states. This class of states includes highly entangled states such as Greenberger-Horne-Zeilinger (GHZ) states and W states, which are of interest in quantum information.

Evaluation of an air spinning process to produce tailored biosynthetic nanofibre scaffolds

International Nuclear Information System (INIS)

Sabbatier, Gad

2014-01-01

We optimised the working parameters of an innovative air spinning device to produce nanofibrous polymer scaffolds for tissue engineering applications. Scanning electron microscopy was performed on the fibre scaffolds which were then used to identify various scaffold morphologies based on the ratio of surface occupied by the polymer fibres on that covered by the entire polymer scaffold assembly. Scaffolds were then produced with the spinning experimental parameters, resulting in 90% of fibres in the overall polymer construct, and were subsequently used to perform a multiple linear regression analysis to highlight the relationship between nanofibre diameter and the air spinning parameters. Polymer solution concentration was deemed as the most significant parameter to control fibre diameter during the spinning process, despite interactions between experimental parameters. Based on these findings, viscosity measurements were performed to clarify the effect of the polymer solution property on scaffold morphology. - Highlights: • An air spinning device for nanofibre scaffold production was optimised. • Relationships between fibre diameter and spinning parameters were established. • Polymer solution concentration was the most significant parameter. • Interactions between experimental parameters also influence the spinning process. • Nanofibres were formed due to polymer chain entanglements

Electro-Deposition Laboratory

Data.gov (United States)

Federal Laboratory Consortium — The electro-deposition laboratory can electro-deposit various coatings onto small test samples and bench level prototypes. This facility provides the foundation for...

Electro-thermal dynamic stripping process : integrating environmentalism with bitumen production

Energy Technology Data Exchange (ETDEWEB)

McGee, B.C.W.; McDonald, C.W. [Society of Petroleum Engineers, Canadian Section, Calgary, AB (Canada)]|[E-T Energy, Calgary, AB (Canada); Little, L. [Society of Petroleum Engineers, Canadian Section, Calgary, AB (Canada)]|[Alberta Energy Research Inst., Edmonton, AB (Canada)

2008-10-15

This paper presented a new method of in situ oil sands extraction developed by Calgary-based E-T Energy. The Electro-Thermal Dynamic Stripping Process (ET-DSP) uses electricity to melt oil sands deposits that are too deep for open pit mining. The energy intensity of production compares favourably with alternative thermal bitumen extraction techniques and water consumption for the process is comparatively low, with all produced water being re-injected into the producing formation without any treatment. With ET-DSP, electrodes are drilled and completed next to the oil sands formation which ensures that the electrical currents are forced to flow to the oil sands formation. The viscosity of the bitumen is lowered by the heat from the current, thereby making the fluid flow more readily into vertical extraction wells. ET-DSP uses electricity directly from the power grid, and does not produce any greenhouse gas (GHG) emissions of its own. The process has the potential to allow operators to focus on areas of oil sands reservoirs that have remained inaccessible. Field studies confirmed that the production of bitumen using this method was achieved with reduced greenhouse gas emissions as compared to other thermal recovery process. The bitumen had trace amount of sand and no emulsions. 5 refs., 5 figs.

Electromigration of Contaminated Soil by Electro-Bioremediation Technique

Science.gov (United States)

Azhar, A. T. S.; Nabila, A. T. A.; Nurshuhaila, M. S.; Shaylinda, M. Z. N.; Azim, M. A. M.

2016-07-01

Soil contamination with heavy metals poses major environmental and human health problems. This problem needs an efficient method and affordable technological solution such as electro-bioremediation technique. The electro-bioremediation technique used in this study is the combination of bacteria and electrokinetic process. The aim of this study is to investigate the effectiveness of Pseudomonas putida bacteria as a biodegradation agent to remediate contaminated soil. 5 kg of kaolin soil was spiked with 5 g of zinc oxide. During this process, the anode reservoir was filled with Pseudomonas putida while the cathode was filled with distilled water for 5 days at 50 V of electrical gradient. The X-Ray Fluorescent (XRF) test indicated that there was a significant reduction of zinc concentration for the soil near the anode with 89% percentage removal. The bacteria count is high near the anode which is 1.3x107 cfu/gww whereas the bacteria count at the middle and near the cathode was 5.0x106 cfu/gww and 8.0x106 cfu/gww respectively. The migration of ions to the opposite charge of electrodes during the electrokinetic process resulted from the reduction of zinc. The results obtained proved that the electro-bioremediation reduced the level of contaminants in the soil sample. Thus, the electro-bioremediation technique has the potential to be used in the treatment of contaminated soil.

Spin-polarized spin excitation spectroscopy

International Nuclear Information System (INIS)

Loth, Sebastian; Lutz, Christopher P; Heinrich, Andreas J

2010-01-01

We report on the spin dependence of elastic and inelastic electron tunneling through transition metal atoms. Mn, Fe and Cu atoms were deposited onto a monolayer of Cu 2 N on Cu(100) and individually addressed with the probe tip of a scanning tunneling microscope. Electrons tunneling between the tip and the substrate exchange energy and spin angular momentum with the surface-bound magnetic atoms. The conservation of energy during the tunneling process results in a distinct onset threshold voltage above which the tunneling electrons create spin excitations in the Mn and Fe atoms. Here we show that the additional conservation of spin angular momentum leads to different cross-sections for spin excitations depending on the relative alignment of the surface spin and the spin of the tunneling electron. For this purpose, we developed a technique for measuring the same local spin with a spin-polarized and a non-spin-polarized tip by exchanging the last apex atom of the probe tip between different transition metal atoms. We derive a quantitative model describing the observed excitation cross-sections on the basis of an exchange scattering process.

Research Based on AMESim of Electro-hydraulic Servo Loading System

Science.gov (United States)

Li, Jinlong; Hu, Zhiyong

2017-09-01

Electro-hydraulic servo loading system is a subject studied by many scholars in the field of simulation and control at home and abroad. The electro-hydraulic servo loading system is a loading device simulation of stress objects by aerodynamic moment and other force in the process of movement, its function is all kinds of gas in the lab condition to analyze stress under dynamic load of objects. The purpose of this paper is the design of AMESim electro-hydraulic servo system, PID control technology is used to configure the parameters of the control system, complete the loading process under different conditions, the optimal design parameters, optimization of dynamic performance of the loading system.

Proposal for electro-optic multiplier based on dual transverse electro-optic Kerr effect.

Science.gov (United States)

Li, Changsheng

2008-10-20

A novel electro-optic multiplier is proposed, which can perform voltage multiplication operation by use of the Kerr medium exhibiting dual transverse electro-optic Kerr effect. In this kind of Kerr medium, electro-optic phase retardation is proportional to the square of its applied electric field, and orientations of the field-induced birefringent axes are only related to the direction of the field. Based on this effect, we can design an electro-optic multiplier by selecting the crystals of 6/mmm, 432, and m3m classes and isotropic Kerr media such as glass. Simple calculation demonstrates that a kind of glass-ceramic material with a large Kerr constant can be used for the design of the proposed electro-optic multiplier.

Rational design of organic electro-optic materials

CERN Document Server

Dalton, L R

2003-01-01

Quantum mechanical calculations are used to optimize the molecular first hyperpolarizability of organic chromophores and statistical mechanical calculations are used to optimize the translation of molecular hyperpolarizability to macroscopic electro-optic activity (to values of greater than 100 pm V sup - sup 1 at telecommunications wavelengths). Macroscopic material architectures are implemented exploiting new concepts in nanoscale architectural engineering. Multi-chromophore-containing dendrimers and dendronized polymers not only permit optimization of electro-optic activity but also of auxiliary properties including optical loss (both absorption and scattering), thermal and photochemical stability and processability. New reactive ion etching and photolithographic techniques permit the fabrication of three-dimensional optical circuitry and the integration of that circuitry with semiconductor very-large-scale integration electronics and silica fibre optics. Electro-optic devices have been fabricated exploiti...

Electro-coagulation-flotation process for algae removal

International Nuclear Information System (INIS)

Gao Shanshan; Yang Jixian; Tian Jiayu; Ma Fang; Tu Gang; Du Maoan

2010-01-01

Algae in surface water have been a long-term issue all over the world, due to their adverse influence on drinking water treatment process as well as drinking water quality. The algae removal by electro-coagulation-flotation (ECF) technology was investigated in this paper. The results indicated that aluminum was an excellent electrode material for algae removal as compared with iron. The optimal parameters determined were: current density = 1 mA/cm 2 , pH = 4-7, water temperature = 18-36 deg. C, algae density = 0.55 x 10 9 -1.55 x 10 9 cells/L. Under the optimal conditions, 100% of algae removal was achieved with the energy consumption as low as 0.4 kWh/m 3 . The ECF performed well in acid and neutral conditions. At low initial pH of 4-7, the cell density of algae was effectively removed in the ECF, mainly through the charge neutralization mechanism; while the algae removal worsened when the pH increased (7-10), and the main mechanism shifted to sweeping flocculation and enmeshment. The mechanisms for algae removal at different pH were also confirmed by atomic force microscopy (AFM) analysis. Furthermore, initial cell density and water temperature could also influence the algae removal. Overall, the results indicated that the ECF technology was effective for algae removal, from both the technical and economical points of view.

Planar quark diagrams and binary spin processes

International Nuclear Information System (INIS)

Grigoryan, A.A.; Ivanov, N.Ya.

1986-01-01

Contributions of planar diagrams to the binary scattering processes are analyzed. The analysis is based on the predictions of quark-gluon picture of strong interactions for the coupling of reggeons with quarks as well as on the SU(6)-classification of hadrons. The dependence of contributions of nonplanar corrections on spins and quark composition of interacting particles is discussed

Efficient and Stable Carbon-coated Nickel Foam Cathodes for the Electro-Fenton Process

International Nuclear Information System (INIS)

Song, Shuqin; Wu, Mingmei; Liu, Yuhui; Zhu, Qiping; Tsiakaras, Panagiotis; Wang, Yi

2015-01-01

Highlights: • Carbon-coated nickel foam (C@NF) was prepared by cycle coating carbon process. • Ni leaching can be effectively controlled at C@NF4 (4 cycle coating times) cathode. • C@NF4 exhibits excellent electro-Fenton performance with desirable stability. • C@NF4 exhibits low energy consumption for DMP degradation. - Abstract: Carbon-coated nickel foam (C@NF) electrodes are prepared via a simple and effective method, hydrothermal-carbonization cycle coating process, characterized by scanning electron microscopy (SEM) with energy dispersive spectrometer (EDS) and employed as the electro-Fenton (E-Fenton) cathode for degrading dimethyl phthalate (DMP) in aqueous solution. For the sake of comparison, nickel foam (NF) electrode and the conventional E-Fenton cathode (graphite gas diffusion electrode (GDE)) are also tested and compared. Experimental results indicate that nickel leaching can be effectively controlled at C@NF4 cathode (4 times cycle coating process), having great significance for promoting the application of NF in E-Fenton system. Moreover, C@NF4 cathode still presents excellent and effective performance on DMP degradation. DMP can be completely degraded within 2 h at −0.5 V and the total organic carbon (TOC) removal reaches as high as 82.1 %, which is almost 3 times as high as that at graphite GDE. Futhermore, the current efficiency for H 2 O 2 generation at C@NF4 is enhanced by 12 times compared to that at NF, and consequently the energy consumption during DMP degradation at C@NF4 is obvious lower than that at both NF cathode and graphite GDE. From the obtained results it can be deduced that C@NF4 is promising to be an attractive alternative E-Fenton cathode for removing organic pollutants in wastewater

Spin-dependent Nucleon Structure Studies at MIT/Bates

International Nuclear Information System (INIS)

Botto, T.

2005-01-01

We present preliminary results from recent measurements of the proton, neutron and deuterium electro-magnetic form factors obtained by the BLAST collaboration at the MIT/Bates Linear Accelerator Facility. BLAST (Bates Large Acceptance Spectrometer Toroid) is a large-acceptance multi-purpose detector dedicated to studies of exclusive spin-dependent electron scattering from internal polarized targets. BLAST makes use of stored electron beam currents in excess of 150 mA with a 60-70% polarization. The electron beam is let through a 15 mm diameter, 60 cm long open-ended storage cell which is fed with ultra-pure, high-polarization H1,D1 gas from an Atomic Beam Source. The target polarization can be rapidly reversed between different vector and tensor target states, thus minimizing systematic uncertainties. The target spin can be oriented to any in-plane direction via a set of Helmholtz coils. Target polarizations in the storage cell of up to 80% (vector) and 70% (tensor) have been routinely achieved over a period of several months. Our data on the D-vector(e-vector,e'n) reaction off vector polarized deuterium allow for a unique extraction of the neutron charge form factor G E n . At same time, complementary measurements of G M n , T20 and the spin-dependent nucleon momentum distributions in deuterium are obtained via the D-vector(e-vector,e'), D (e-vector,e'd) and D (e-vector,e'p) reactions. In addition, BLAST data on vector polarized hydrogen will provide novel measurements of the GE/GM form-factor ratio on the proton as well as of the spin-dependent electro-excitation of the Δ(1232) resonance. Such comprehensive program on few body physics is now well underway and preliminary data will be presented

Chaotic spin exchange: is the spin non-flip rate observable?

International Nuclear Information System (INIS)

Senba, Masayoshi

1994-01-01

If spin exchange is of the Poisson nature, that is, if the time distribution of collisions obeys an exponential distribution function and the collision process is random, the muon spin depolarization is determined only by the spin flip rate regardless of the spin non-flip rate. In this work, spin exchange is discussed in the case of chaotic spin exchange, where the distribution of collision time sequences, generated by a deterministic equation, is exponential but not random (deterministic chaos). Even though this process has the same time distribution as a Poisson process, the muon polarization is affected by the spin non-flip rate. Having an exponential time distribution function is not a sufficient condition for the non-observation of the spin non-flip rate and it is essential that the process is also random. (orig.)

An interfacially plasticized electro-responsive hydrogel for transdermal electro-activated and modulated (TEAM) drug delivery

NARCIS (Netherlands)

Indermun, S.; Choonara, Y.E.; Kumar, Pradeep; Toit, Du L.C.; Modi, G.; Luttge, R.; Pillay, V.

2014-01-01

This paper highlights the use of hydrogels in controlled drug delivery, and their application in stimuli responsive, especially electro-responsive, drug release. electro-conductive hydrogels (ECHs) displaying electro-responsive drug release were synthesized from semi-interpenetrating networks

A Review on the Fabrication of Electro spun Polymer Electrolyte Membrane for Direct Methanol Fuel Cell

International Nuclear Information System (INIS)

Junoh, H.; Jaafar, J.; Norddin, M.N.A.M.; Ismail, A.F.; Othman, M.H.D.; Rahman, M.A.; Yusof, N.; Salleh, W.N.W.; Junoh, H.; Jaafar, J.; Norddin, M.N.A.M.; Ismail, A.F.; Othman, M.H.D.; Rahman, M.A.; Yusof, N.; Salleh, W.N.W.; Hamid Ilbeygi, H.

2014-01-01

Proton exchange membrane (PEM) is an electrolyte which behaves as important indicator for fuel cell’s performance. Research and development (R and D) on fabrication of desirable PEM have burgeoned year by year, especially for direct methanol fuel cell (DMFC). However, most of the R and Ds only focus on the parent polymer electrolyte rather than polymer inorganic composites. This might be due to the difficulties faced in producing good dispersion of inorganic filler within the polymer matrix, which would consequently reduce the DMFC’s performance. Electro spinning is a promising technique to cater for this arising problem owing to its more widespread dispersion of inorganic filler within the polymer matrix, which can reduce the size of the filler up to nano scale. There has been a huge development on fabricating electrolyte nano composite membrane, regardless of the effect of electro spun nano composite membrane on the fuel cell’s performance. In this present paper, issues regarding the R and D on electro spun sulfonated poly (ether ether ketone) (SPEEK)/inorganic nano composite fiber are addressed.

Spin drift and spin diffusion currents in semiconductors

Energy Technology Data Exchange (ETDEWEB)

Idrish Miah, M [Nanoscale Science and Technology Centre and School of Biomolecular and Physical Sciences, Griffith University, Nathan, Brisbane, QLD 4111 (Australia)], E-mail: m.miah@griffith.edu.au

2008-09-15

On the basis of a spin drift-diffusion model, we show how the spin current is composed and find that spin drift and spin diffusion contribute additively to the spin current, where the spin diffusion current decreases with electric field while the spin drift current increases, demonstrating that the extension of the spin diffusion length by a strong field does not result in a significant increase in spin current in semiconductors owing to the competing effect of the electric field on diffusion. We also find that there is a spin drift-diffusion crossover field for a process in which the drift and diffusion contribute equally to the spin current, which suggests a possible method of identifying whether the process for a given electric field is in the spin drift or spin diffusion regime. Spin drift-diffusion crossover fields for GaAs are calculated and are found to be quite small. We derive the relations between intrinsic spin diffusion length and the spin drift-diffusion crossover field of a semiconductor for different electron statistical regimes. The findings resulting from this investigation might be important for semiconductor spintronics.

Spin drift and spin diffusion currents in semiconductors

Directory of Open Access Journals (Sweden)

M Idrish Miah

2008-01-01

Full Text Available On the basis of a spin drift-diffusion model, we show how the spin current is composed and find that spin drift and spin diffusion contribute additively to the spin current, where the spin diffusion current decreases with electric field while the spin drift current increases, demonstrating that the extension of the spin diffusion length by a strong field does not result in a significant increase in spin current in semiconductors owing to the competing effect of the electric field on diffusion. We also find that there is a spin drift-diffusion crossover field for a process in which the drift and diffusion contribute equally to the spin current, which suggests a possible method of identifying whether the process for a given electric field is in the spin drift or spin diffusion regime. Spin drift-diffusion crossover fields for GaAs are calculated and are found to be quite small. We derive the relations between intrinsic spin diffusion length and the spin drift-diffusion crossover field of a semiconductor for different electron statistical regimes. The findings resulting from this investigation might be important for semiconductor spintronics.

Spin drift and spin diffusion currents in semiconductors

International Nuclear Information System (INIS)

Idrish Miah, M

2008-01-01

On the basis of a spin drift-diffusion model, we show how the spin current is composed and find that spin drift and spin diffusion contribute additively to the spin current, where the spin diffusion current decreases with electric field while the spin drift current increases, demonstrating that the extension of the spin diffusion length by a strong field does not result in a significant increase in spin current in semiconductors owing to the competing effect of the electric field on diffusion. We also find that there is a spin drift-diffusion crossover field for a process in which the drift and diffusion contribute equally to the spin current, which suggests a possible method of identifying whether the process for a given electric field is in the spin drift or spin diffusion regime. Spin drift-diffusion crossover fields for GaAs are calculated and are found to be quite small. We derive the relations between intrinsic spin diffusion length and the spin drift-diffusion crossover field of a semiconductor for different electron statistical regimes. The findings resulting from this investigation might be important for semiconductor spintronics.

Bidirectional optimization of the melting spinning process.

Science.gov (United States)

Liang, Xiao; Ding, Yongsheng; Wang, Zidong; Hao, Kuangrong; Hone, Kate; Wang, Huaping

2014-02-01

A bidirectional optimizing approach for the melting spinning process based on an immune-enhanced neural network is proposed. The proposed bidirectional model can not only reveal the internal nonlinear relationship between the process configuration and the quality indices of the fibers as final product, but also provide a tool for engineers to develop new fiber products with expected quality specifications. A neural network is taken as the basis for the bidirectional model, and an immune component is introduced to enlarge the searching scope of the solution field so that the neural network has a larger possibility to find the appropriate and reasonable solution, and the error of prediction can therefore be eliminated. The proposed intelligent model can also help to determine what kind of process configuration should be made in order to produce satisfactory fiber products. To make the proposed model practical to the manufacturing, a software platform is developed. Simulation results show that the proposed model can eliminate the approximation error raised by the neural network-based optimizing model, which is due to the extension of focusing scope by the artificial immune mechanism. Meanwhile, the proposed model with the corresponding software can conduct optimization in two directions, namely, the process optimization and category development, and the corresponding results outperform those with an ordinary neural network-based intelligent model. It is also proved that the proposed model has the potential to act as a valuable tool from which the engineers and decision makers of the spinning process could benefit.

Present status of metrology of electro-optical surveillance systems

Science.gov (United States)

Chrzanowski, K.

2017-10-01

There has been a significant progress in equipment for testing electro-optical surveillance systems over the last decade. Modern test systems are increasingly computerized, employ advanced image processing and offer software support in measurement process. However, one great challenge, in form of relative low accuracy, still remains not solved. It is quite common that different test stations, when testing the same device, produce different results. It can even happen that two testing teams, while working on the same test station, with the same tested device, produce different results. Rapid growth of electro-optical technology, poor standardization, limited metrology infrastructure, subjective nature of some measurements, fundamental limitations from laws of physics, tendering rules and advances in artificial intelligence are major factors responsible for such situation. Regardless, next decade should bring significant improvements, since improvement in measurement accuracy is needed to sustain fast growth of electro-optical surveillance technology.

Theory-Guided Design of Organic Electro-Optic Materials and Devices

Directory of Open Access Journals (Sweden)

Stephanie Benight

2011-08-01

Full Text Available Integrated (multi-scale quantum and statistical mechanical theoretical methods have guided the nano-engineering of controlled intermolecular electrostatic interactions for the dramatic improvement of acentric order and thus electro-optic activity of melt-processable organic polymer and dendrimer electro-optic materials. New measurement techniques have permitted quantitative determination of the molecular order parameters, lattice dimensionality, and nanoscale viscoelasticity properties of these new soft matter materials and have facilitated comparison of theoretically-predicted structures and thermodynamic properties with experimentally-defined structures and properties. New processing protocols have permitted further enhancement of material properties and have facilitated the fabrication of complex device structures. The integration of organic electro-optic materials into silicon photonic, plasmonic, and metamaterial device architectures has led to impressive new performance metrics for a variety of technological applications.

New type of ordering process with volume change of molecules in the spin-crossover transition, and its new aspects of dynamical processes

Science.gov (United States)

Miyashita, Seiji; Nishino, Masamichi; Konishi, Yusuke; Tokoro, Hiroko; Boukheddaden, Kamel; Varret, François; Rikvold, Per Arne

2009-02-01

Bistability between the high- and low-spin states in spin-crossover materials provides a complex temperature dependence of the ordering processes. Thermodynamic properties of the ordering phenomena were studied in a unified way, and a generic structure of the ordering processes was proposed. The origin of the interaction among the spins was also discussed, and a new mechanism based on an elastic interaction among distortions due to the volume of a molecule depending on its spin state was also proposed. With this mechanism, the typical pressure dependence of the ordering processes can be reproduced. Moreover, we studied the type of criticality of the phase transition and pointed out that the present model possesses critical behaviour belonging to the mean-field universality class. There, the spin-spin correlation function is constant at long distances and does not show an exponential decay in contrast to short-range models. It is also pointed out that the model with periodic boundary conditions does not show ordering clusters, even near the critical point or in the process of spinodal decomposition. This indicates that critical opalescence would not be observed in this model. No cluster appears, either in photo-excitation process from the low-spin state at low temperatures. On the other hand, with open boundary conditions, the system shows a cluster structure. The effects of the boundary conditions are also discussed.

Synthesis of Gold Nanoparticles by Electro-reduction Method and Their Application as an Electro-hyperthermia System

International Nuclear Information System (INIS)

Yoon, Young Il; Kim, Kwangsoo; Kwon, Yongsoo; Cho, Heesang; Yoon, Changjin; Yoon, Taejong; Lee, Hak Jong

2014-01-01

We report the successful preparation of gold nanoparticles (Au NPs) using a novel electroreduction process, which is simple, fast, and environmentally friendly (toxic chemicals such as strong reducing agents are not required). Our process allows for the mass production of Au NPs and adequate particle size control. The Au NPs prepared show high biocompatibility and are non-toxic to healthy human cells. By applying radiofrequency (RF) ablation, we monitored the electro-hyperthermia effect of the Au NPs at different RFs. The Au NPs exhibit a fast increase in temperature to 55 .deg. C within 5 min during the application of an RF of 13 MHz. This temperature rise is sufficient to promote apoptosis through thermal stress. Our work suggests that the selective Au NP-mediated electro-hyperthermia therapy for tumor cells under an RF of 13 MHz has great potential as a clinical treatment for specific tumor ablation

Design of an Electro-Optic Modulator for High Speed Communications

Science.gov (United States)

Espinoza, David

The telecommunications and computer technology industries have been requiring higher communications speeds at all levels for devices, components and interconnected systems. Optical devices and optical interconnections are a viable alternative over other traditional technologies such as copper-based interconnections. Latency reductions can be achieved through the use of optical interconnections. Currently, a particular architecture for optical interconnections is being studied at the University of Colorado at Boulder in the EMT/NANO project, called Broadcast Optical Interconnects for Global Communication in Many-Core Chip Multiprocessor. As with most types of networks, including optical networks, one of the most important components are modulators. Therefore adequate design and fabrication techniques for modulators contribute to higher modulation rates which lead to improve the efficiency and reductions in the latency of the optical network. Electro-optical modulators are presented in this study as an alternative to achieve this end. In recent years, nonlinear optical (NLO) materials have been used for the fabrication of high-speed electro-optical modulators. Polymers doped with chromophores are an alternative among NLO materials because they can develop large electro-optic coefficients and low dielectric constants. These two factors are critical for achieving high-speed modulation rates. These polymer-based electro-optical modulators can be fabricated using standard laboratory techniques, such as polymer spin-coating onto substrates, UV bleaching to achieve a refractive index variation and poling techniques to align the chromophores in cured polymers. The design of the electro-optic modulators require the use of the optical parameters of the materials to be used. Therefore the characterization of these materials is a required previous step. This characterization is performed by the fabrication of chromophores-doped polymer samples and conducting transmission and

Substitution of efficient electro-technologies for thermal end-uses to traditional processes. Screening of possibilities and applications under study

International Nuclear Information System (INIS)

Menga, P.; Grattieri, W.; Korn, G.; Malinverni, R.

1996-01-01

ENEL's long-lasting commitment in rationalizing the energy end-uses, has lead to the assessment of the potential for the substitution, in the field of thermal uses, of traditional processes with efficient electro-technologies. The evaluation has been performed by taking in account the advantages for the user, in terms of the reduction in operating costs (energy included), for the electricity industry (increase in kWh sales), and for the Society (savings in primary energy consumption). The analysis allowed to identify many applications for which the primary energy saving is jointly obtained with significant extra-energy advantages for the end user. In order to validate the effectiveness of innovative electro-technologies, a demonstration activity, by means of pilot plants, is in progress. (author)

Spin physics through unpolarized processes

Science.gov (United States)

Lu, Zhun

2016-02-01

This article presents a review of our present understanding of the spin structure of the unpolarized hadron. Particular attention is paid to the quark sector at leading twist, namely, the quark Boer-Mulders function, which describes the transverse polarization of the quark inside an unpolarized hadron. After introducing the operator definition of the Boer-Mulders function, a detailed treatment of different non-perturbative calculations of the Boer-Mulders functions is provided. The phenomenology in Drell-Yan processes and semi-inclusive leptoproduction, including the extraction of the quark and antiquark Boer-Mulders functions from experimental data, is presented comprehensively. Finally, prospects for future theoretical studies and experimental measurements are presented in brief.

Spin physics at RHIC

International Nuclear Information System (INIS)

Tannenbaum, M.J.

1996-01-01

Operation of RHIC with two beams of highly polarized protons (70%, either longitudinal or transverse) at high luminosity L = 2 x 10 32 cm -2 sec -1 for two months/year will allow the STAR and PHENIX detectors to perform high statististics studies of polarization phenomena in the perturbative region of hard scattering where both QCD and ElectroWeak theory make detailed predictions for polarization effects. The collision c.m. energy, √s = 200 - 500 GeV, represents a new domain for the study of spin. Direct photon production will be used to measure the gluon polarization in the polarized proton. A new twist comes from W-boson production which is expected to be 100% parity violating and will thus allow measurements of flavor separated Quark and antiquark (u, bar u, d, bar d) polarization distributions. Searches for parity violation in strong interaction processes such as jet and leading particle production will be a sensitive way to look for new physics beyond the standard model, one possibility being quark substructure

Application of Electro Chemical Machining for materials used in extreme conditions

Science.gov (United States)

Pandilov, Z.

2018-03-01

Electro-Chemical Machining (ECM) is the generic term for a variety of electrochemical processes. ECM is used to machine work pieces from metal and metal alloys irrespective of their hardness, strength or thermal properties, through the anodic dissolution, in aerospace, automotive, construction, medical equipment, micro-systems and power supply industries. The Electro Chemical Machining is extremely suitable for machining of materials used in extreme conditions. General overview of the Electro-Chemical Machining and its application for different materials used in extreme conditions is presented.

Electro-oxidation of methanol on copper in alkaline solution

International Nuclear Information System (INIS)

Heli, H.; Jafarian, M.; Mahjani, M.G.; Gobal, F.

2004-01-01

The electro-oxidation of methanol on copper in alkaline solutions has been studied by the methods of cyclic voltammetry, quasi-steady state polarization and chronoamperometry. It has been found that in the course of an anodic potential sweep the electro-oxidation of methanol follows the formation of Cu III and is catalysed by this species through a mediated electron transfer mechanism. The reaction also continues in the early stages of the reversed cycle until it is stopped by the prohibitively negative potentials. The process is diffusion controlled and the current-time responses follow Cottrellian behavior. The rate constants, turnover frequency, anodic transfer coefficient and the apparent activation energy of the electro-oxidation reaction are reported

Energy-producing electro-flocculation for harvest of Dunaliella salina.

Science.gov (United States)

Liu, Qing; Zhang, Meng; Lv, Tao; Chen, Hongjun; Chika, Anthony Okonkwo; Xiang, Changli; Guo, Minxue; Wu, Minghui; Li, Jianjun; Jia, Lishan

2017-10-01

In this study, an efficient electro-flocculation process for Dunaliella salina with energy production by aluminum-air battery has been successfully applied. The formed aluminum hydroxide hydrates during discharging of battery were positively charged, which have a great potential for microalgae flocculation. The precipitation of aluminum hydroxide hydrates by algae also could improve the performance of aluminum-air battery. The harvesting efficiency could reach 97% in 20mins with energy production of 0.11kWh/kg. This discharging electro-flocculation (DEF) technology provides a new energy producing process to effectively harvest microalgae. Copyright © 2017 Elsevier Ltd. All rights reserved.

Systems engineering and analysis of electro-optical and infrared systems

CERN Document Server

Arrasmith, William Wolfgang

2015-01-01

Introduction to Electro-optic and Infrared (EO/IR) Systems Engineering?Radiation in the Visible and Infrared Parts of the Electromagnetic SpectrumRadiation SourcesThe Effect of the Atmosphere on Optical PropagationBasic OpticsOptical ModulationThe Detection of Optical RadiationNoise in the Optical Detection ProcessTechnical Performance Measures and Metrics of Optical DetectorsModern Detectors and their Measures of PerformanceThe Effects of Cooling on Optical Detector NoiseSignal and Image ProcessingElectro-Optic and Infrared Systems AnalysisLaser Imaging Systems?Spectral Imaging?LIDAR and LADA

Spin-Hall effect and emergent antiferromagnetic phase transition in n-Si

Science.gov (United States)

Lou, Paul C.; Kumar, Sandeep

2018-04-01

Spin current experiences minimal dephasing and scattering in Si due to small spin-orbit coupling and spin-lattice interactions is the primary source of spin relaxation. We hypothesize that if the specimen dimension is of the same order as the spin diffusion length then spin polarization will lead to non-equilibrium spin accumulation and emergent phase transition. In n-Si, spin diffusion length has been reported up to 6 μm. The spin accumulation in Si will modify the thermal transport behavior of Si, which can be detected with thermal characterization. In this study, we report observation of spin-Hall effect and emergent antiferromagnetic phase transition behavior using magneto-electro-thermal transport characterization. The freestanding Pd (1 nm)/Ni80Fe20 (75 nm)/MgO (1 nm)/n-Si (2 μm) thin film specimen exhibits a magnetic field dependent thermal transport and spin-Hall magnetoresistance behavior attributed to Rashba effect. An emergent phase transition is discovered using self-heating 3ω method, which shows a diverging behavior at 270 K as a function of temperature similar to a second order phase transition. We propose that spin-Hall effect leads to the spin accumulation and resulting emergent antiferromagnetic phase transition. We propose that the length scale for Rashba effect can be equal to the spin diffusion length and two-dimensional electron gas is not essential for it. The emergent antiferromagnetic phase transition is attributed to the site inversion asymmetry in diamond cubic Si lattice.

I. Advances in NMR Signal Processing. II. Spin Dynamics in Quantum Dissipative Systems

Energy Technology Data Exchange (ETDEWEB)

Lin, Yung-Ya [Univ. of California, Berkeley, CA (United States)

1998-11-01

Part I. Advances in IVMR Signal Processing. Improvements of sensitivity and resolution are two major objects in the development of NMR/MRI. A signal enhancement method is first presented which recovers signal from noise by a judicious combination of a priordmowledge to define the desired feasible solutions and a set theoretic estimation for restoring signal properties that have been lost due to noise contamination. The effect of noise can be significantly mitigated through the process of iteratively modifying the noisy data set to the smallest degree necessary so that it possesses a collection of prescribed properties and also lies closest to the original data set. A novel detection-estimation scheme is then introduced to analyze noisy and/or strongly damped or truncated FIDs. Based on exponential modeling, the number of signals is detected based on information estimated using the matrix pencil method. theory and the spectral parameters are Part II. Spin Dynamics in body dipole-coupled systems Quantum Dissipative Systems. Spin dynamics in manyconstitutes one of the most fundamental problems in magnetic resonance and condensed-matter physics. Its many-spin nature precludes any rigorous treatment. ‘Therefore, the spin-boson model is adopted to describe in the rotating frame the influence of the dipolar local fields on a tagged spin. Based on the polaronic transform and a perturbation treatment, an analytical solution is derived, suggesting the existence of self-trapped states in the. strong coupling limit, i.e., when transverse local field >> longitudinal local field. Such nonlinear phenomena originate from the joint action of the lattice fluctuations and the reaction field. Under semiclassical approximation, it is found that the main effect of the reaction field is the renormalization of the Hamiltonian of interest. Its direct consequence is the two-step relaxation process: the spin is initially localized in a quasiequilibrium state, which is later detrapped by

THEORY OF ACTIVE HITTINGS IS IN PROCESSES OF ELECTRO-COAGULATION THE ADMIXTURES IN WATER TECHNOLOGICAL ENVIRONMENT

Directory of Open Access Journals (Sweden)

В.В. Березуцький

2012-10-01

Full Text Available  In the article theoretical bases of electro-coagulation of admixtures are examined in a water technological environment with the use of theory of the active hittings, which are based on the results of the executed researches and analysis of scientific information. Application of theory of the active hittings is in coagulation, provides high efficiency of process of extraction of admixtures from water environments during minimization of energy consumption and expenses of materials.

Electro-Deformation of Fused Cells in a Microfluidic Array Device

Directory of Open Access Journals (Sweden)

Yan Liu

2016-11-01

Full Text Available We present a new method of analyzing the deformability of fused cells in a microfluidic array device. Electrical stresses—generated by applying voltages (4–20 V across discrete co-planar microelectrodes along the side walls of a microfluidic channel—have been used to electro-deform fused and unfused stem cells. Under an electro-deformation force induced by applying an alternating current (AC signal, we observed significant electro-deformation phenomena. The experimental results show that the fused stem cells were stiffer than the unfused stem cells at a relatively low voltage (<16 V. However, at a relatively high voltage, the fused stem cells were more easily deformed than were the unfused stem cells. In addition, the electro-deformation process is modeled based on the Maxwell stress tensor and structural mechanics of cells. The theoretical results show that a positive correlation is found between the deformation of the cell and the applied voltage, which is consistent with the experimental results. Combined with a numerical analysis and experimental study, the results showed that the significant difference of the deformation ratio of the fused and unfused cells is not due to their size difference. This demonstrates that some other properties of cell membranes (such as the membrane structure were also changed in the electrofusion process, in addition to the size modification of that process.

167th International School of Physics "Enrico Fermi" : Strangeness and Spin in Fundamental Physics

CERN Document Server

Bressani, T; Feliciello, A; Ratcliffe, Ph G

2008-01-01

Strangeness and Spin in Fundamental Physics is dedicated to the discussion of the role played by two subtle and somehow puzzling quantum numbers, the strangeness and the spin, in fundamental physics. They both relate to basic properties of the fundamental quantum field theories describing strong and electro-weak interactions and to their phenomenological applications. In some instances, like the partonic spin structure of the proton, they are deeply correlated. The many puzzling results recently obtained by measuring several spin asymmetries have stimulated gigantic progresses in the study of the spin structure of protons and neutrons. Intense theoretical activity has discovered new features of non-perturbative QCD, like strong correlations between the spin and the intrinsic motions of quarks inside the nucleons. The purpose of this publication is that of providing a complete, updated and critical account of the most recent and relevant discoveries in the above fields, both from the experimental and theoretic...

Recent developments on ion-exchange membranes and electro-membrane processes.

Science.gov (United States)

Nagarale, R K; Gohil, G S; Shahi, Vinod K

2006-02-28

Rapid growth of chemical and biotechnology in diversified areas fuels the demand for the need of reliable green technologies for the down stream processes, which include separation, purification and isolation of the molecules. Ion-exchange membrane technologies are non-hazardous in nature and being widely used not only for separation and purification but their application also extended towards energy conversion devices, storage batteries and sensors etc. Now there is a quite demand for the ion-exchange membrane with better selectivities, less electrical resistance, high chemical, mechanical and thermal stability as well as good durability. A lot of work has been done for the development of these types of ion-exchange membranes during the past twenty-five years. Herein we have reviewed the preparation of various types of ion-exchange membranes, their characterization and applications for different electro-membrane processes. Primary attention has been given to the chemical route used for the membrane preparation. Several general reactions used for the preparation of ion-exchange membranes were described. Methodologies used for the characterization of these membranes and their applications were also reviewed for the benefit of readers, so that they can get all information about the ion-exchange membranes at one platform. Although there are large number of reports available regarding preparations and applications of ion-exchange membranes more emphasis were predicted for the usefulness of these membranes or processes for solving certain type of industrial or social problems. More efforts are needed to bring many products or processes to pilot scale and extent their applications.

On nonlinear thermo-electro-elasticity.

Science.gov (United States)

Mehnert, Markus; Hossain, Mokarram; Steinmann, Paul

2016-06-01

Electro-active polymers (EAPs) for large actuations are nowadays well-known and promising candidates for producing sensors, actuators and generators. In general, polymeric materials are sensitive to differential temperature histories. During experimental characterizations of EAPs under electro-mechanically coupled loads, it is difficult to maintain constant temperature not only because of an external differential temperature history but also because of the changes in internal temperature caused by the application of high electric loads. In this contribution, a thermo-electro-mechanically coupled constitutive framework is proposed based on the total energy approach. Departing from relevant laws of thermodynamics, thermodynamically consistent constitutive equations are formulated. To demonstrate the performance of the proposed thermo-electro-mechanically coupled framework, a frequently used non-homogeneous boundary-value problem, i.e. the extension and inflation of a cylindrical tube, is solved analytically. The results illustrate the influence of various thermo-electro-mechanical couplings.

Electro-weak theory

International Nuclear Information System (INIS)

Deshpande, N.G.

1980-01-01

By electro-weak theory is meant the unified field theory that describes both weak and electro-magnetic interactions. The development of a unified electro-weak theory is certainly the most dramatic achievement in theoretical physics to occur in the second half of this century. It puts weak interactions on the same sound theoretical footing as quantum elecrodynamics. Many theorists have contributed to this development, which culminated in the works of Glashow, Weinberg and Salam, who were jointly awarded the 1979 Nobel Prize in physics. Some of the important ideas that contributed to this development are the theory of beta decay formulated by Fermi, Parity violation suggested by Lee and Yang, and incorporated into immensely successful V-A theory of weak interactions by Sudarshan and Marshak. At the same time ideas of gauge invariance were applied to weak interaction by Schwinger, Bludman and Glashow. Weinberg and Salam then went one step further and wrote a theory that is renormalizable, i.e., all higher order corrections are finite, no mean feat for a quantum field theory. The theory had to await the development of the quark model of hadrons for its completion. A description of the electro-weak theory is given

ETEM Studies of Electrodes and Electro-catalysts

DEFF Research Database (Denmark)

Jooss, Christian; Mildner, Stephanie; Beleggia, Marco

2016-01-01

Environmental TEM is an excellent tool for gaining insight into the atomic and electronic structure of electro-catalysts under operating conditions. Several electrochemical reactions such as oxidation/reduction processes of electrodes, heterogeneous gas phase catalysis of water splitting...

Large spin current injection in nano-pillar-based lateral spin valve

Energy Technology Data Exchange (ETDEWEB)

Nomura, Tatsuya [Department of Physics, Kyushu University, 744 Motooka, Fukuoka, 819-0395 (Japan); Ohnishi, Kohei; Kimura, Takashi, E-mail: t-kimu@phys.kyushu-u.ac.jp [Department of Physics, Kyushu University, 744 Motooka, Fukuoka, 819-0395 (Japan); Research Center for Quantum Nano-Spin Sciences, Kyushu University, 744 Motooka, Fukuoka, 819-0395 (Japan)

2016-08-26

We have investigated the influence of the injection of a large pure spin current on a magnetization process of a non-locally located ferromagnetic dot in nano-pillar-based lateral spin valves. Here, we prepared two kinds of the nano-pillar-type lateral spin valve based on Py nanodots and CoFeAl nanodots fabricated on a Cu film. In the Py/Cu lateral spin valve, although any significant change of the magnetization process of the Py nanodot has not been observed at room temperature. The magnetization reversal process is found to be modified by injecting a large pure spin current at 77 K. Switching the magnetization by the nonlocal spin injection has also been demonstrated at 77 K. In the CoFeAl/Cu lateral spin valve, a room temperature spin valve signal was strongly enhanced from the Py/Cu lateral spin valve because of the highly spin-polarized CoFeAl electrodes. The room temperature nonlocal switching has been demonstrated in the CoFeAl/Cu lateral spin valve.

Kinetics and energy efficiency for the degradation of 1,4-dioxane by electro-peroxone process

Energy Technology Data Exchange (ETDEWEB)

Wang, Huijiao; Bakheet, Belal; Yuan, Shi; Li, Xiang; Yu, Gang [School of Environment, Tsinghua University, Beijing 100084 (China); Murayama, Seiichi [Power and Industrial Systems R& D Center, Toshiba Corporation, Fuchu-shi, Tokyo (Japan); Wang, Yujue, E-mail: wangyujue@tsinghua.edu.cn [School of Environment, Tsinghua University, Beijing 100084 (China)

2015-08-30

Highlights: • E-peroxone couples electrolysis with ozonation to driven peroxone reaction for pollutant degradation. • Significant amounts of ·OH can be efficiently produced in the E-peroxone process. • E-peroxone greatly enhances 1,4-dioxane degradation kinetics compared with ozonation and electrolysis. • E-peroxone consumes less energy for 1,4-dioxane mineralization than ozonation and electrolysis. • E-peroxone offers a cost-effective and energy-efficient alternative to degrade 1,4-dioxane. - Abstract: Degradation of 1,4-dioxane by ozonation, electrolysis, and their combined electro-peroxone (E-peroxone) process was investigated. The E-peroxone process used a carbon-polytetrafluorethylene cathode to electrocatalytically convert O{sub 2} in the sparged ozone generator effluent (O{sub 2} and O{sub 3} gas mixture) to H{sub 2}O{sub 2}. The electro-generated H{sub 2}O{sub 2} then react with sparged O{sub 3} to yield aqueous ·OH, which can in turn oxidize pollutants rapidly in the bulk solution. Using p-chlorobenzoic acid as ·OH probe, the pseudo-steady concentration of ·OH was determined to be ∼0.744 × 10{sup −9} mM in the E-peroxone process, which is approximately 10 and 186 times of that in ozonation and electrolysis using a Pt anode. Thanks to its higher ·OH concentration, the E-peroxone process eliminated 96.6% total organic carbon (TOC) from a 1,4-dioxane solution after 2 h treatment with a specific energy consumption (SEC) of 0.376 kWh g{sup −1} TOC{sub removed}. In comparison, ozonation and electrolysis using a boron-doped diamond anode removed only ∼6.1% and 26.9% TOC with SEC of 2.43 and 0.558 kWh g{sup −1} TOC{sub removed}, respectively. The results indicate that the E-peroxone process can significantly improve the kinetics and energy efficiency for 1,4-dioxane mineralization as compared to the two individual processes. The E-peroxone process may thus offer a highly effective and energy-efficient alternative to treat 1,4-dioxane

Combined heterogeneous Electro-Fenton and biological process for the treatment of stabilized landfill leachate.

Science.gov (United States)

Baiju, Archa; Gandhimathi, R; Ramesh, S T; Nidheesh, P V

2018-03-15

Treatment of stabilized landfill leachate is a great challenge due to its poor biodegradability. Present study made an attempt to treat this wastewater by combining electro-Fenton (E-Fenton) and biological process. E-Fenton treatment was applied prior to biological process to enhance the biodegradability of leachate, which will be beneficial for the subsequent biological process. This study also investigates the efficiency of iron molybdophosphate (FeMoPO) nanoparticles as a heterogeneous catalyst in E-Fenton process. The effects of initial pH, catalyst dosage, applied voltage and electrode spacing on Chemical Oxygen Demand (COD) removal efficiency were analyzed to determine the optimum conditions. Heterogeneous E-Fenton process gave 82% COD removal at pH 2, catalyst dosage of 50 mg/L, voltage 5 V, electrode spacing 3 cm and electrode area 25 cm 2 . Combined E-Fenton and biological treatment resulted an overall COD removal of 97%, bringing down the final COD to 192 mg/L. Copyright © 2018 Elsevier Ltd. All rights reserved.

Heterogeneous electro-Fenton catalyst for 1-butylpyridinium chloride degradation.

Science.gov (United States)

Meijide, Jessica; Pazos, Marta; Sanromán, Maria Ángeles

2017-10-15

The application of the electro-Fenton process for organic compound mineralisation has been widely reported over the past years. However, operational problems related to the use of soluble iron salt as a homogeneous catalyst involve the development of novel catalysts that are able to operate in a wide pH range. For this purpose, polyvinyl alcohol-alginate beads, containing goethite as iron, were synthesised and evaluated as heterogeneous electro-Fenton catalyst for 1-butylpyridinium chloride mineralisation. The influence of catalyst dosage and pH solution on ionic liquid degradation was analysed, achieving almost total oxidation after 60 min under optimal conditions (2 g/L catalyst concentration and pH 3). The results showed good catalyst stability and reusability, although its effectiveness decreases slightly after three successive cycles. Furthermore, a plausible mineralisation pathway was proposed based on the oxidation byproducts determined by chromatographic techniques. Finally, the Microtox® test revealed notable detoxification after treatment which demonstrates high catalyst ability for pyridinium-based ionic liquid degradation by the electro-Fenton process.

Design of a treatment pilot by electro-coagulation and electro-flotation of high charged liquid effluents; Conception d'un pilote de traitement par electrocoagulation-electroflottation d'effluents liquides fortement charges

Energy Technology Data Exchange (ETDEWEB)

Cames, M.C.; Leclerc, J.P.; Valentin, G.; Sanchez-Calvo, L.; Lapicque, F. [Centre National de la Recherche Scientifique (CNRS-ENSIC), Lab. des Sciences du Genie Chimique, 54 - Nancy (France); Rostan, A.; Muller, P. [Centre de Recherche pour l' Environnement, l' Energie et le Dechet, Vivendi Environnement, 78 - Limay (France)

2001-07-01

The possibilities of the electro-coagulation and electro-flotation process has been studied on many industrial effluents by cells. The results show that the process efficiency is conditioned by the effluent nature and the dissolved aluminium quantity, what ever the initial rate of Carbon Organic Total (COT). Other parameters as the current density and the circulation speed are not significant. (A.L.B.)

A multilayer electro-thermal model of pouch battery during normal discharge and internal short circuit process

International Nuclear Information System (INIS)

Chen, Mingbiao; Bai, Fanfei; Song, Wenji; Lv, Jie; Lin, Shili

2017-01-01

Highlights: • 2D network equivalent circuit considers the interplay of cell units. • The temperature non-uniformity Φ of multilayer model is bigger than that of lumped model. • The temperature non-uniformity is quantified and the reason of non-uniformity is analyzed. • Increasing the thermal conductivity of the separator can effectively relieve the heat spot effect of ISC. - Abstract: As the electrical and thermal characteristic will affect the batteries’ safety, performance, calendar life and capacity fading, an electro-thermal coupled model for pouch battery LiFePO_4/C is developed in normal discharge and internal short circuit process. The battery is discretized into many cell elements which are united as a 2D network equivalent circuit. The electro-thermal model is solved with finite difference method. Non-uniformity of current distribution and temperature distribution is simulated and the result is validated with experiment data at various discharge rates. Comparison of the lumped model and the multilayer structure model shows that the temperature non-uniformity Φ of multilayer model is bigger than that of lumped model and shows more precise. The temperature non-uniformity is quantified and the reason of non-uniformity is analyzed. The electro-thermal model can also be used to guide the safety design of battery. The temperature of the ISC element near tabs is the highest because the equivalent resistance of the external circuit (not including the ISC element) is the smallest when the resistance of cell units is small. It is found that increasing the thermal conductivity of integrated layer can effectively relieve the heat spot effect of ISC.

Virtual processes and superradiance in spin-boson modes

International Nuclear Information System (INIS)

Alcalde, M. Aparicio; Kullock, R.; Svaiter, N.F.

2008-01-01

We consider spin-boson models composed by a single bosonic mode and an ensemble of N identical two-level atoms. The situation where the coupling between the bosonic mode and the atoms generates real and virtual processes is studied, where the whole system is in thermal equilibrium with a reservoir at temperature β -1 . Phase transitions from ordinary fluorescence to super radiant phase in three different models is investigated. First a model where the coupling between the bosonic mode and the j - th atom is via the pseudo-spin operator σ (j) z is studied. Second, we investigate the generalized Dicke model, introducing different coupling constants between the single mode bosonic field and the environment, g 1 and g 2 for rotating and counter-rotating terms, respectively. Finally it is considered a modified version of the generalized Dicke model with intensity-dependent coupling in the rotating terms. In the first model the zero mode contributes to render the canonical entropy a negative quantity for low temperatures. The last two models presents phase transitions, even when only Hamiltonian terms which generates virtual processes are considered. (author)

The reactor design and comparison of Fenton, electro-Fenton and photoelectro-Fenton processes for mineralization of benzene sulfonic acid (BSA)

International Nuclear Information System (INIS)

Ting, W.-P.; Lu, M.-C.; Huang, Y.-H.

2008-01-01

A new approach for promoting ferric reduction efficiency using a different electrochemical cell and the photoelectro-Fenton process has been developed. The use of UVA light and electric current as electron donors can efficiently initiate the Fenton reaction. Benzene sulfonic acid (BSA) was the target compound in this study. The parameters investigated to evaluate the reactor design include the electrode working area, electrode distance, energy consumption. Furthermore, the study also contains the intermediates and the mineralization efficiency of electrolysis, Fenton, electro-Fenton and photoelectro-Fenton process. Oxalic acid, the major intermediate of aromatic compound degradation, can complex with ferric ions. Meanwhile, a double cathode reactor could increase the current efficiency by 7%, which would translate to greater ferrous production and a higher degradation rate. Although the current efficiency of an electrode distance 5.5 cm device is 19% higher than 3.0 cm, results show that after 2 h of electrolysis the electronic expense using an electrode gap of 5.5 cm is much higher than 3.0 cm. The final TOC removal efficiency was 46, 64 and 72% using the Fenton, electro-Fenton and photoelectron-Fenton processes, respectively

Optimization and Surface Modification of Al-6351 Alloy Using SiC-Cu Green Compact Electrode by Electro Discharge Coating Process

Science.gov (United States)

Chakraborty, Sujoy; Kar, Siddhartha; Dey, Vidyut; Ghosh, Subrata Kumar

2017-06-01

This paper introduces the surface modification of Al-6351 alloy by green compact SiC-Cu electrode using electro-discharge coating (EDC) process. A Taguchi L-16 orthogonal array is employed to investigate the process by varying tool parameters like composition and compaction load and electro-discharge machining (EDM) parameters like pulse-on time and peak current. Material deposition rate (MDR), tool wear rate (TWR) and surface roughness (SR) are measured on the coated specimens. An optimum condition is achieved by formulating overall evaluation criteria (OEC), which combines multi-objective task into a single index. The signal-to-noise (S/N) ratio, and the analysis of variance (ANOVA) is employed to investigate the effect of relevant process parameters. A confirmation test is conducted based on optimal process parameters and experimental results are provided to illustrate the effectiveness of this approach. The modified surface is characterized by optical microscope and X-ray diffraction (XRD) analysis. XRD analysis of the deposited layer confirmed the transfer of tool materials to the work surface and formation of inter-metallic phases. The micro-hardness of the resulting composite layer is also measured which is 1.5-3 times more than work material’s one and highest layer thickness (LT) of 83.644μm has been successfully achieved.

FACTORS AND MOTIVES FOR THE SPIN-OFF PROCESS

Directory of Open Access Journals (Sweden)

Igor B. Khmelev

2013-01-01

Full Text Available This article is about the factors that encourage managers to use spin offs as a restructuring tool, and about the main motives of spin-off transactions. Attention is focused on the nature of spin-offs. There is a classification of the driving factors of spin-offs from the theoretical viewpoint and the degree of this question elaboration in economic literature. Four factors are marked: industrial, life cycle, company size and support of the parent company. The basic spin-off motives are pointed in this article.

Improvisation of mechanical and electrical properties of Cu by reinforcing MWCNT using modified electro-co-deposition process

Science.gov (United States)

Belgamwar, Sachin U.; Sharma, N. N.

2018-04-01

Multi-walled Carbon nanotubes–copper (MWCNT/Cu) composite powders with variable MWCNT content were synthesized by modified electro-co-deposition method. The electro-co-deposited MWCNT/Cu powders were consolidated by conventional compaction and sintering process. The consolidated products were then hot rolled and cold drawn to fine wires. The MWCNT/Cu composite wire samples were characterized for electrical and mechanical properties. We have been able to achieve an increase of around 8% in electrical conductivity of the form wires repeatedly. It has been observed that there was gradual improvement in the properties with reinforcement of MWCNT in the copper matrix. The betterment of electrical property has been achieved with simultaneous improvement in mechanical properties of the wire. The yield strength of MWCNT/Cu composite wire was found to be four times and the tensile strength two times greater than that of pure copper. The improved properties are attributed to the proper distribution of MWCNTs in the copper matrix and excellent interfacial bonding between MWCNT and composite copper fabricated by the modified method.

Stimulated polarization wave process in spin 3/2 chains

International Nuclear Information System (INIS)

Furman, G. B.

2007-01-01

Stimulated wave of polarization, triggered by a flip of a single spin, presents a simple model of quantum amplification. Recently, it has been demonstrated that, in an idealized one-dimensional Ising spin 1/2 chain with nearest-neighbor interactions and realistic spin 1/2 chain including the natural dipole-dipole interactions, irradiated by a weak resonant transverse field, a wave of flipped spins can be triggered by a single spin flip. Here we focuse on control of polarization wave in chain of spin 3/2, where the nuclear quadrupole interaction is dominant. Results of simulations for 1D spin chains and rings with up to five spins are presented.

Electro-membrane processes for flue gas cleaning

Energy Technology Data Exchange (ETDEWEB)

Larsen, T. F.

1997-12-31

Various techniques for NO removal in Membrane Contactor were considered. However the NO absorption in a liquid adsorbent with chemical enhancement and its ease for regeneration, was selected as the most practicable choice. Various different compounds for chemical enhancement were studied and Fe(II)-chelate enhanced adsorbent was selected for further studies. The technical feasibility of Fe(II)-chelate enhanced adsorbent for obtaining greater than 80% NO removal have been successfully established. Even though the membrane area required for greater than 80% NO removal has been found to be about 500 m{sup 2}/MW{sub c} (compared to 50 - 150 m{sup 2}/MW{sub c}, for 95% SO{sub 2} removal, depending on the membrane characteristics), suitable Membrane Contactor design has been proposed for carrying out the process at an acceptable gas side pressure drop. The electro-membrane processes for the regeneration of adsorbents have been studied both theoretically and experimentally. The theoretical studies have concerned the study of basic functions of both the bipolar membranes and charge laden (anion/cation) membranes. Suitable experimental techniques have been devised for studying of these basic parameters (e.g. charge transport number, salt diffusion through membranes, current-voltage characteristics of bipolar membranes and electrical resistance of charge laden membranes). These parameters have further been utilized in the mechanistic model of combined membranes in an ED cell (electrodialysis). Based on these fundamental studies and analysis of process requirements, suitable configuration of ED cell has been developed and verified by experimental studies. The effect of both the stack design parameters (e.g. number of cells, membrane type and spacer design) and the operational parameters (e.g. temperature, electrolyte concentration, liquid velocity and current density) have been studied for optimization of energy consumption for regeneration of loaded adsorbents. As a result

Development of a trickle bed reactor of electro-Fenton process for wastewater treatment

International Nuclear Information System (INIS)

Lei, Yangming; Liu, Hong; Shen, Zhemin; Wang, Wenhua

2013-01-01

Highlights: • An electrochemical trickle bed reactor was composed of C-PTFE-coated graphite chips. • The trickle bed reactor had a high H 2 O 2 production rate in a dilute electrolyte. • An azo dye was effectively decomposed by the electro-Fenton process in the reactor. -- Abstract: To avoid electrolyte leakage and gas bubbles in the electro-Fenton (E-Fenton) reactors using a gas diffusion cathode, we developed a trickle bed cathode by coating a layer composed of carbon black and polytetrafluoroethylene (C-PTFE) onto graphite chips instead of carbon cloth. The trickle bed cathode was optimized by single-factor and orthogonal experiments, in which carbon black, PTFE, and a surfactant were considered as the determinant of the performance of graphite chips. In the reactor assembled by the trickle bed cathode, H 2 O 2 was generated with a current of 0.3 A and a current efficiency of 60%. This performance was attributed to the fine distribution of electrolyte and air, as well as the effective oxygen transfer from the gas phase to the electrolyte–cathode interface. In terms of H 2 O 2 generation and current efficiency, the developed trickle bed reactor had a performance comparable to that of the conventional E-Fenton reactor using a gas diffusion cathode. Further, 123 mg L −1 of reactive brilliant red X-3B in aqueous solution was decomposed in the optimized trickle bed reactor as E-Fenton reactor. The decolorization ratio reached 97% within 20 min, and the mineralization reached 87% within 3 h

Electro-optic transceivers for terahertz-wave applications

International Nuclear Information System (INIS)

Chen, Q.; Tani, M.; Jiang, Zhiping; Zhang, X.-C.

2001-01-01

Because of the reciprocal behavior of the optical rectification and the electro-optic effect in a nonlinear optical crystal, an electro-optic transceiver can alternately transmit pulsed electromagnetic radiation (optical rectification) and detect the return signal (electro-optic effect) in the same crystal. However, the optimal condition of the electro-optic transceiver may be very different from that of the spatially separated emitter and receiver. We present a detailed description of the crystal-orientation dependence of the electro-optic terahertz devices (transmitter, receiver, and transceiver). It is found that for a (110) zinc-blende electro-optical crystal, the efficiency of the electro-optic transceiver will be optimized when the angle between the polarization of the optical pump beam and the crystallographic z axis [0,0,1] is 26 degree. Meanwhile, for a (111) crystal, the angle between the optical beam and the crystallographic direction [-1,-1,2] should be 23 degree. The experimental results from a (110) ZnTe transceiver verify theoretical calculations and demonstrate a direct way to optimize the working efficiency of an electro-optic terahertz transceiver. [copyright] 2001 Optical Society of America

Strategies in electro-chemical machining of tungsten for divertor application

International Nuclear Information System (INIS)

Krauss, W.; Holstein, N.; Konys, J.

2007-01-01

For future application in a fusion power system a modular structured He cooled divertor concept is investigated under the framework of EFDA which is based on the use of pure W or W alloys for the thermally highly loaded parts. Due to the underlying physico-chemical principles electro-chemical machining (ECM) is the only shaping process which will not introduce microstructural defects, e.g. microcracks into work pieces as known by example from electro-discharge machining (EDM). However, ECM processes have no industrial application in W machining up to yet due to passivation effects using standard electrolytes known from steel working. Therefore, a systematical electrochemical development program was launched, and the electrochemical behavior of W was examined and passivation effects could be eliminated, successfully. The electrochemical shaping processes can be divided into two main categories. The first one is M-ECM, which represents the lithographic route based on structured anode masks, and the other is C-ECM, working with a negatively structured cathode as tool which is copied by electro-chemical dissolution. Both ECM branches are discussed on base of first machined structured parts, showing their process depending advantages and potential enhancements are revealed by applying pulsed currents instead of DC dissolution technique

Electro-optic diffraction grating tuned laser

International Nuclear Information System (INIS)

Hughes, R.S.

1975-01-01

An electro-optic diffraction grating tuned laser comprising a laser medium, output mirror, retro-reflective grating and an electro-optic diffraction grating beam deflector positioned between the laser medium and the reflective diffraction grating is described. An optional angle multiplier may be used between the electro-optic diffraction grating and the reflective grating. (auth)

Spin Hall and spin swapping torques in diffusive ferromagnets

KAUST Repository

Pauyac, C. O.

2017-12-08

A complete set of the generalized drift-diffusion equations for a coupled charge and spin dynamics in ferromagnets in the presence of extrinsic spin-orbit coupling is derived from the quantum kinetic approach, covering major transport phenomena, such as the spin and anomalous Hall effects, spin swapping, spin precession and relaxation processes. We argue that the spin swapping effect in ferromagnets is enhanced due to spin polarization, while the overall spin texture induced by the interplay of spin-orbital and spin precessional effects displays a complex spatial dependence that can be exploited to generate torques and nucleate/propagate domain walls in centrosymmetric geometries without use of external polarizers, as opposed to the conventional understanding of spin-orbit mediated torques.

Spin Hall and spin swapping torques in diffusive ferromagnets

KAUST Repository

Pauyac, C. O.; Chshiev, M.; Manchon, Aurelien; Nikolaev, S. A.

2017-01-01

A complete set of the generalized drift-diffusion equations for a coupled charge and spin dynamics in ferromagnets in the presence of extrinsic spin-orbit coupling is derived from the quantum kinetic approach, covering major transport phenomena, such as the spin and anomalous Hall effects, spin swapping, spin precession and relaxation processes. We argue that the spin swapping effect in ferromagnets is enhanced due to spin polarization, while the overall spin texture induced by the interplay of spin-orbital and spin precessional effects displays a complex spatial dependence that can be exploited to generate torques and nucleate/propagate domain walls in centrosymmetric geometries without use of external polarizers, as opposed to the conventional understanding of spin-orbit mediated torques.

Fundamentals of electro-engineering I

International Nuclear Information System (INIS)

Rapsik, M.; Smola, M.; Bohac, M.; Mucha, M.

2004-01-01

This is the text-book of the fundamentals of electro-engineering. It contains the following chapters: (1) Selected terms in electro-engineering; (2) Fundamental electric values; (3) Energy and their transformations; (4) Water, hydro-energy and hydro-energetic potential of the Slovak Republic; (5) Nuclear power engineering; (6) Conventional thermal power plants; (7) Heating and cogeneration of electric power and heat production; (8) Equipment of electricity supply system; (9) Measurements in electro-engineering ; (10) Regulation of frequency and voltage, electric power quality

Acetaminophen degradation by electro-Fenton and photoelectro-Fenton using a double cathode electrochemical cell

International Nuclear Information System (INIS)

Luna, Mark Daniel G. de; Veciana, Mersabel L.; Su, Chia-Chi; Lu, Ming-Chun

2012-01-01

Highlights: ► The electro-Fenton reactor using a double cathode electrochemical cell was applied. ► The initial Fe 2+ concentration was the most significant parameter for the acetaminophen degradation. ► Thirteen intermediates were identified and a degradation pathway was proposed. - Abstract: Acetaminophen is a widely used drug worldwide and is one of the most frequently detected in bodies of water making it a high priority trace pollutant. This study investigated the applicability of the electro-Fenton and photoelectro-Fenton processes using a double cathode electrochemical cell in the treatment of acetaminophen containing wastewater. The Box–Behnken design was used to determine the effects of initial Fe 2+ and H 2 O 2 concentrations and applied current density. Results showed that all parameters positively affected the degradation efficiency of acetaminophen with the initial Fe 2+ concentration being the most significant parameter for both processes. The acetaminophen removal efficiency for electro-Fenton was 98% and chemical oxygen demand (COD) removal of 43% while a 97% acetaminophen removal and 42% COD removal were observed for the photoelectro-Fenton method operated at optimum conditions. The electro-Fenton process was only able to obtain 19% total organic carbon (TOC) removal while the photoelectro-Fenton process obtained 20%. Due to negligible difference between the treatment efficiencies of the two processes, the electro-Fenton method was proven to be more economically advantageous. The models obtained from the study were applicable to a wide range of acetaminophen concentrations and can be used in scale-ups. Thirteen different types of intermediates were identified and a degradation pathway was proposed.

Electro-optic polymers for high speed modulators

NARCIS (Netherlands)

Balakrishnan, M.; Diemeer, Mart; Driessen, A.; Faccini, M.; Verboom, Willem; Reinhoudt, David; Leinse, Arne; Megret, P.; Wuilpart, M.; Bette, S.; Staquet, N.

2005-01-01

Different electro-optic polymer systems are analyzed with respect to their electro-optic activity, glass transition temperature $(T_g)$ and photodefinable properties. The polymers tested are polysulfone (PS) and polycarbonate (PC). The electro-optic chromophore,

Bulk electron spin polarization generated by the spin Hall current

OpenAIRE

Korenev, V. L.

2005-01-01

It is shown that the spin Hall current generates a non-equilibrium spin polarization in the interior of crystals with reduced symmetry in a way that is drastically different from the previously well-known equilibrium polarization during the spin relaxation process. The steady state spin polarization value does not depend on the strength of spin-orbit interaction offering possibility to generate relatively high spin polarization even in the case of weak spin-orbit coupling.

Bulk electron spin polarization generated by the spin Hall current

Science.gov (United States)

Korenev, V. L.

2006-07-01

It is shown that the spin Hall current generates a nonequilibrium spin polarization in the interior of crystals with reduced symmetry in a way that is drastically different from the previously well-known “equilibrium” polarization during the spin relaxation process. The steady state spin polarization value does not depend on the strength of spin-orbit interaction offering possibility to generate relatively high spin polarization even in the case of weak spin-orbit coupling.

Effects of Micromachining Processes on Electro-Osmotic Flow Mobility of Glass Surfaces

Directory of Open Access Journals (Sweden)

Norihisa Miki

2013-03-01

Full Text Available Silica glass is frequently used as a device material for micro/nano fluidic devices due to its excellent properties, such as transparency and chemical resistance. Wet etching by hydrofluoric acid and dry etching by neutral loop discharge (NLD plasma etching are currently used to micromachine glass to form micro/nano fluidic channels. Electro-osmotic flow (EOF is one of the most effective methods to drive liquids into the channels. EOF mobility is affected by a property of the micromachined glass surfaces, which includes surface roughness that is determined by the manufacturing processes. In this paper, we investigate the effect of micromaching processes on the glass surface topography and the EOF mobility. We prepared glass surfaces by either wet etching or by NLD plasma etching, investigated the surface topography using atomic force microscopy, and attempted to correlate it with EOF generated in the micro-channels of the machined glass. Experiments revealed that the EOF mobility strongly depends on the surface roughness, and therefore upon the fabrication process used. A particularly strong dependency was observed when the surface roughness was on the order of the electric double layer thickness or below. We believe that the correlation described in this paper can be of great help in the design of micro/nano fluidic devices.

Spin structure in high energy processes: Proceedings

Energy Technology Data Exchange (ETDEWEB)

DePorcel, L.; Dunwoodie, C. [eds.

1994-12-01

This report contains papers as the following topics: Spin, Mass, and Symmetry; physics with polarized Z{sup 0}s; spin and precision electroweak physics; polarized electron sources; polarization phenomena in quantum chromodynamics; polarized lepton-nucleon scattering; polarized targets in high energy physics; spin dynamics in storage rings and linear accelerators; spin formalism and applications to new physics searches; precision electroweak physics at LEP; recent results on heavy flavor physics from LEP experiments using 1990--1992 data; precise measurement of the left-right cross section asymmetry in Z boson production by electron-positron collisions; preliminary results on heavy flavor physics at SLD; QCD tests with SLD and polarized beams; recent results from TRISTAN at KEK; recent B physics results from CLEO; searching for the H dibaryon at Brookhaven; recent results from the compton observatory; the spin structure of the deuteron; spin structure of the neutron ({sup 3}HE) and the Bjoerken sum rule; a consumer`s guide to lattice QCD results; top ten models constrained by b {yields} sy; a review of the Fermilab fixed target program; results from the D0 experiment; results from CDF at FNAL; quantum-mechanical suppression of bremsstrahlung; report from the ZEUS collaboration at HERA; physics from the first year of H1 at HERA, and hard diffraction. These papers have been cataloged separately elsewhere.

Spin structure in high energy processes: Proceedings

International Nuclear Information System (INIS)

DePorcel, L.; Dunwoodie, C.

1994-12-01

This report contains papers as the following topics: Spin, Mass, and Symmetry; physics with polarized Z 0 s; spin and precision electroweak physics; polarized electron sources; polarization phenomena in quantum chromodynamics; polarized lepton-nucleon scattering; polarized targets in high energy physics; spin dynamics in storage rings and linear accelerators; spin formalism and applications to new physics searches; precision electroweak physics at LEP; recent results on heavy flavor physics from LEP experiments using 1990--1992 data; precise measurement of the left-right cross section asymmetry in Z boson production by electron-positron collisions; preliminary results on heavy flavor physics at SLD; QCD tests with SLD and polarized beams; recent results from TRISTAN at KEK; recent B physics results from CLEO; searching for the H dibaryon at Brookhaven; recent results from the compton observatory; the spin structure of the deuteron; spin structure of the neutron ( 3 HE) and the Bjoerken sum rule; a consumer's guide to lattice QCD results; top ten models constrained by b → sy; a review of the Fermilab fixed target program; results from the D0 experiment; results from CDF at FNAL; quantum-mechanical suppression of bremsstrahlung; report from the ZEUS collaboration at HERA; physics from the first year of H1 at HERA, and hard diffraction. These papers have been cataloged separately elsewhere

Theoretical exploration of structural, electro-optical and magnetic properties of gallium-doped silicon carbide nanotubes

Science.gov (United States)

Behzad, Somayeh; Chegel, Raad; Moradian, Rostam; Shahrokhi, Masoud

2014-09-01

The effects of gallium doping on the structural, electro-optical and magnetic properties of (8,0) silicon carbide nanotube (SiCNT) are investigated by using spin-polarized density functional theory. It is found from the calculation of the formation energies that gallium substitution for silicon atom is preferred. Our results show that gallium substitution at either single carbon or silicon atom site in SiCNT could induce spontaneous magnetization. The optical studies based on dielectric function indicate that new transition peaks and a blue shift are observed after gallium doping.

Polymer Coatings Reduce Electro-osmosis

Science.gov (United States)

Herren, Blair J.; Snyder, Robert; Shafer, Steven G.; Harris, J. Milton; Van Alstine, James M.

1989-01-01

Poly(ethylene glycol) film controls electrostatic potential. Electro-osmosis in quartz or glass chambers reduced or reversed by coating inside surface of chambers with monomacromolecular layers of poly(ethylene glycol). Stable over long times. Electrostatic potential across surface of untreated glass or plastic chamber used in electro-phoresis is negative and attracts cations in aqueous electrolyte. Cations solvated, entrains flow of electrolyte migrating toward cathode. Electro-osmotic flow interferes with desired electrophoresis of particles suspended in electrolyte. Polymer coats nontoxic, transparent, and neutral, advantageous for use in electrophoresis.

Nanocrystalline Mn-Mo-Ce Oxide Anode Doped Rare Earth Ce and Its Selective Electro-catalytic Performance

Directory of Open Access Journals (Sweden)

SHI Yan-hua

2017-09-01

Full Text Available The anode oxide of nanocrystalline Mn-Mo-Ce was prepared by anode electro-deposition technology, and its nanostructure and selective electro-catalytic performance were investigated using the SEM, EDS, XRD, HRTEM, electrochemical technology and oxygen evolution efficiency testing. Furthermore, the selective electro-catalytic mechanism of oxygen evolution and chlorine depression was discussed. The results show that the mesh-like nanostructure Mn-Mo-Ce oxide anode with little cerium doped is obtained, and the oxygen evolution efficiency for the anode in the seawater is 99.51%, which means a high efficiency for the selective electro-catalytic for the oxygen evolution. Due to the structural characteristics of γ-MnO2, the OH- ion is preferentially absorbed, while Cl- absorption is depressed. OH- accomplishes the oxygen evolution process during the valence transition electrocatalysis of Mn4+/Mn3+, completing the selective electro-catalysis process. Ce doping greatly increases the reaction activity, and promotes the absorption and discharge; the rising interplanar spacing between active (100 crystalline plane promotes OH- motion and the escape of newborn O2, so that the selective electro-catalytic property with high efficient oxygen evolution and chlorine depression is achieved from the nano morphology effect.

Scalable electro-photonic integration concept based on polymer waveguides

Science.gov (United States)

Bosman, E.; Van Steenberge, G.; Boersma, A.; Wiegersma, S.; Harmsma, P.; Karppinen, M.; Korhonen, T.; Offrein, B. J.; Dangel, R.; Daly, A.; Ortsiefer, M.; Justice, J.; Corbett, B.; Dorrestein, S.; Duis, J.

2016-03-01

A novel method for fabricating a single mode optical interconnection platform is presented. The method comprises the miniaturized assembly of optoelectronic single dies, the scalable fabrication of polymer single mode waveguides and the coupling to glass fiber arrays providing the I/O's. The low cost approach for the polymer waveguide fabrication is based on the nano-imprinting of a spin-coated waveguide core layer. The assembly of VCSELs and photodiodes is performed before waveguide layers are applied. By embedding these components in deep reactive ion etched pockets in the silicon substrate, the planarity of the substrate for subsequent layer processing is guaranteed and the thermal path of chip-to-substrate is minimized. Optical coupling of the embedded devices to the nano-imprinted waveguides is performed by laser ablating 45 degree trenches which act as optical mirror for 90 degree deviation of the light from VCSEL to waveguide. Laser ablation is also implemented for removing parts of the polymer stack in order to mount a custom fabricated connector containing glass fiber arrays. A demonstration device was built to show the proof of principle of the novel fabrication, packaging and optical coupling principles as described above, combined with a set of sub-demonstrators showing the functionality of the different techniques separately. The paper represents a significant part of the electro-photonic integration accomplishments in the European 7th Framework project "Firefly" and not only discusses the development of the different assembly processes described above, but the efforts on the complete integration of all process approaches into the single device demonstrator.

Extreme nonlinear terahertz electro-optics in diamond for ultrafast pulse switching

Science.gov (United States)

Shalaby, Mostafa; Vicario, Carlo; Hauri, Christoph P.

2017-03-01

Polarization switching of picosecond laser pulses is a fundamental concept in signal processing [C. Chen and G. Liu, Annu. Rev. Mater. Sci. 16, 203 (1986); V. R. Almeida et al., Nature 431, 1081 (2004); and A. A. P. Pohl et al., Photonics Sens. 3, 1 (2013)]. Conventional switching devices rely on the electro-optical Pockels effect and work at radio frequencies. The ensuing gating time of several nanoseconds is a bottleneck for faster switches which is set by the performance of state-of-the-art high-voltage electronics. Here we show that by substituting the electric field of several kV/cm provided by modern electronics by the MV/cm field of a single-cycle THz laser pulse, the electro-optical gating process can be driven orders of magnitude faster, at THz frequencies. In this context, we introduce diamond as an exceptional electro-optical material and demonstrate a pulse gating time as fast as 100 fs using sub-cycle THz-induced Kerr nonlinearity. We show that THz-induced switching in the insulator diamond is fully governed by the THz pulse shape. The presented THz-based electro-optical approach overcomes the bandwidth and switching speed limits of conventional MHz/GHz electronics and establishes the ultrafast electro-optical gating technology for the first time in the THz frequency range. We finally show that the presented THz polarization gating technique is applicable for advanced beam diagnostics. As a first example, we demonstrate tomographic reconstruction of a THz pulse in three dimensions.

Epithelial Fluid Transport is Due to Electro-osmosis (80%), Plus Osmosis (20%).

Science.gov (United States)

Fischbarg, Jorge; Hernandez, Julio A; Rubashkin, Andrey A; Iserovich, Pavel; Cacace, Veronica I; Kusnier, Carlos F

2017-06-01

Epithelial fluid transport, an important physiological process shrouded in a long-standing enigma, may finally be moving closer to a solution. We propose that, for the corneal endothelium, relative proportions for the driving forces for fluid transport are 80% of paracellular electro-osmosis, and 20% classical transcellular osmosis. These operate in a cyclical process with a period of 9.2 s, which is dictated by the decrease and exhaustion of cellular Na + . Paracellular electro-osmosis is sketched here, and partially discussed as much as the subject still allows; transcellular osmosis is presented at length.

Eavesdropping on spin waves inside the domain-wall nanochannel via three-magnon processes

Science.gov (United States)

Zhang, Beining; Wang, Zhenyu; Cao, Yunshan; Yan, Peng; Wang, X. R.

2018-03-01

One recent breakthrough in the field of magnonics is the experimental realization of reconfigurable spin-wave nanochannels formed by a magnetic domain wall with a width of 10-100 nm [Wagner et al., Nat. Nano. 11, 432 (2016), 10.1038/nnano.2015.339]. This remarkable progress enables an energy-efficient spin-wave propagation with a well-defined wave vector along its propagating path inside the wall. In the mentioned experiment, a microfocus Brillouin light scattering spectroscopy was taken in a line-scans manner to measure the frequency of the bounded spin wave. Due to their localization nature, the confined spin waves can hardly be detected from outside the wall channel, which guarantees the information security to some extent. In this work, we theoretically propose a scheme to detect/eavesdrop on the spin waves inside the domain-wall nanochannel via nonlinear three-magnon processes. We send a spin wave (ωi,ki) in one magnetic domain to interact with the bounded mode (ωb,kb) in the wall, where kb is parallel with the domain-wall channel defined as the z ̂ axis. Two kinds of three-magnon processes, i.e., confluence and splitting, are expected to occur. The confluence process is conventional: conservation of energy and momentum parallel with the wall indicates a transmitted wave in the opposite domain with ω (k ) =ωi+ωb and (ki+kb-k ) .z ̂=0 , while the momentum perpendicular to the domain wall is not necessary to be conserved due to the nonuniform internal field near the wall. We predict a stimulated three-magnon splitting (or "magnon laser") effect: the presence of a bound magnon propagating along the domain wall channel assists the splitting of the incident wave into two modes, one is ω1=ωb,k1=kb identical to the bound mode in the channel, and the other one is ω2=ωi-ωb with (ki-kb-k2) .z ̂=0 propagating in the opposite magnetic domain. Micromagnetic simulations confirm our theoretical analysis. These results demonstrate that one is able to uniquely

Acetaminophen degradation by electro-Fenton and photoelectro-Fenton using a double cathode electrochemical cell

Energy Technology Data Exchange (ETDEWEB)

Luna, Mark Daniel G. de [Department of Chemical Engineering, University of the Philippines, 1011 Diliman, Quezon City (Philippines); Environmental Engineering Graduate Program, University of the Philippines, 1011 Diliman, Quezon City (Philippines); Veciana, Mersabel L. [Environmental Engineering Graduate Program, University of the Philippines, 1011 Diliman, Quezon City (Philippines); Su, Chia-Chi [Department of Environmental Resources Management, Chia Nan University of Pharmacy and Science, Tainan 717, Taiwan (China); Lu, Ming-Chun, E-mail: mmclu@mail.chan.edu.tw [Department of Environmental Resources Management, Chia Nan University of Pharmacy and Science, Tainan 717, Taiwan (China)

2012-05-30

Highlights: Black-Right-Pointing-Pointer The electro-Fenton reactor using a double cathode electrochemical cell was applied. Black-Right-Pointing-Pointer The initial Fe{sup 2+} concentration was the most significant parameter for the acetaminophen degradation. Black-Right-Pointing-Pointer Thirteen intermediates were identified and a degradation pathway was proposed. - Abstract: Acetaminophen is a widely used drug worldwide and is one of the most frequently detected in bodies of water making it a high priority trace pollutant. This study investigated the applicability of the electro-Fenton and photoelectro-Fenton processes using a double cathode electrochemical cell in the treatment of acetaminophen containing wastewater. The Box-Behnken design was used to determine the effects of initial Fe{sup 2+} and H{sub 2}O{sub 2} concentrations and applied current density. Results showed that all parameters positively affected the degradation efficiency of acetaminophen with the initial Fe{sup 2+} concentration being the most significant parameter for both processes. The acetaminophen removal efficiency for electro-Fenton was 98% and chemical oxygen demand (COD) removal of 43% while a 97% acetaminophen removal and 42% COD removal were observed for the photoelectro-Fenton method operated at optimum conditions. The electro-Fenton process was only able to obtain 19% total organic carbon (TOC) removal while the photoelectro-Fenton process obtained 20%. Due to negligible difference between the treatment efficiencies of the two processes, the electro-Fenton method was proven to be more economically advantageous. The models obtained from the study were applicable to a wide range of acetaminophen concentrations and can be used in scale-ups. Thirteen different types of intermediates were identified and a degradation pathway was proposed.

Development of a trickle bed reactor of electro-Fenton process for wastewater treatment

Energy Technology Data Exchange (ETDEWEB)

Lei, Yangming [Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 401122 (China); School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Liu, Hong, E-mail: liuhong@cigit.ac.cn [Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 401122 (China); Shen, Zhemin, E-mail: zmshen@sjtu.edu.cn [School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Wang, Wenhua [School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)

2013-10-15

Highlights: • An electrochemical trickle bed reactor was composed of C-PTFE-coated graphite chips. • The trickle bed reactor had a high H{sub 2}O{sub 2} production rate in a dilute electrolyte. • An azo dye was effectively decomposed by the electro-Fenton process in the reactor. -- Abstract: To avoid electrolyte leakage and gas bubbles in the electro-Fenton (E-Fenton) reactors using a gas diffusion cathode, we developed a trickle bed cathode by coating a layer composed of carbon black and polytetrafluoroethylene (C-PTFE) onto graphite chips instead of carbon cloth. The trickle bed cathode was optimized by single-factor and orthogonal experiments, in which carbon black, PTFE, and a surfactant were considered as the determinant of the performance of graphite chips. In the reactor assembled by the trickle bed cathode, H{sub 2}O{sub 2} was generated with a current of 0.3 A and a current efficiency of 60%. This performance was attributed to the fine distribution of electrolyte and air, as well as the effective oxygen transfer from the gas phase to the electrolyte–cathode interface. In terms of H{sub 2}O{sub 2} generation and current efficiency, the developed trickle bed reactor had a performance comparable to that of the conventional E-Fenton reactor using a gas diffusion cathode. Further, 123 mg L{sup −1} of reactive brilliant red X-3B in aqueous solution was decomposed in the optimized trickle bed reactor as E-Fenton reactor. The decolorization ratio reached 97% within 20 min, and the mineralization reached 87% within 3 h.

Electro-catalytic oxidation of reactive Orange 107 using cerium doped oxides of Nd3+ nanoparticle

International Nuclear Information System (INIS)

Rajkumar, K.; Muthukumar, M.; Mangalaraja, R.V.

2011-01-01

A new rare earth doped cerium oxide powder was used as a catalyst to investigate the removal of colour and TOC from simulated wastewater of Reactive Orange 107. The electro oxidation process was carried out in the reactor in presence of an electrolyte NaCl. Graphite electrode was used as anode and cathode and electrolysis were carried out at a current density of 34.96 mAcm -2 with a catalyst concentration of 0.05g L -1 . In order to find the efficiency of nanocatalyst, experiments were also conducted without catalyst. From the experiment, it was found that complete colour removal was achieved on electrocatalytic oxidation as well as electro oxidation. When comparing the above processes, catalytic oxidation shows more efficient than electro oxidation. With respect to the degradation of the dye, catalytic oxidation shows more TOC removal than the oxidation taken place without catalyst. It infers that even though the electro-catalytic oxidation process achieves complete decolouration but it does not achieve complete mineralisation. The FTIR and GCMS studies confirmed the formation of by-products. (author)

Spin current through quantum-dot spin valves

International Nuclear Information System (INIS)

Wang, J; Xing, D Y

2006-01-01

We report a theoretical study of the influence of the Coulomb interaction on the equilibrium spin current in a quantum-dot spin valve, in which the quantum dot described by the Anderson impurity model is coupled to two ferromagnetic leads with noncollinear magnetizations. In the Kondo regime, electrons transmit through the quantum dot via higher-order virtual processes, in which the spin of either lead electrons or a localized electron on the quantum dot may reverse. It is found that the magnitude of the spin current decreases with increasing Coulomb interactions due to spin flip effects on the dot. However, the spatial direction of the spin current remains unchanged; it is determined only by the exchange coupling between two noncollinear magnetizations

Electro-sensitivity: the physicians-laymen relationship under the test of an environmental pathology

International Nuclear Information System (INIS)

Oullion, Amandine

2014-01-01

This academic work addresses sociological and anthropological aspects of contemporary techniques. The authors more particularly examined how electro-sensitivity contributes to the re-composition of the relationship between physicians and laymen. After some methodological and theoretical considerations, the authors first addresses this issue from a macro-sociological and political point of view, i.e. by discussing the role of laymen in the definition and addressing of public health issues. They analyse the implication of electro-sensitive persons in the process of politicisation of their disease, and in research arrangements implemented on these issues. Then, they address the way electro-sensitivity reshapes the meeting between physician and patient. In the last part, they address the way electro-sensitivity questions the medical institution itself in terms of medical practices, and of power relationships within this institution

Hybrid friction stir welding for dissimilar materials through electro-plastic effect

Science.gov (United States)

Liu, Xun; Lan, Shuhuai; Ni, Jun

2018-05-29

A hybrid Friction Stir Welding approach and device for dissimilar materials joining employing Electro-Plastic Effect. The approach and device include an introduction of high density, short period current pulses into traditional friction stir welding process, which therefore can generate a localized softened zone in the workpiece during plastic stirring without significant additional temperature increase. This material softened zone is created by high density current pulses based on Electro-Plastic Effect and will move along with the friction stir welding tool. Smaller downward force, larger processing window and better joint quality for dissimilar materials are expected to be achieved through this hybrid welding technique.

Reduction of COD in wastewater from an organized tannery industrial region by Electro-Fenton process

International Nuclear Information System (INIS)

Kurt, Ugur; Apaydin, Omer; Gonullu, M. Talha

2007-01-01

Advanced oxidation processes (AOPs) have led the way in the treatment of aqueous waste and are rapidly becoming the chosen technology for many applications. In this paper, COD reduction potential of leather tanning industry wastewaters by Electro-Fenton (EF) oxidation, as one of the AOPs, was experimentally evaluated. The wastewater sample was taken from an outlet of an equalization basin in a common treatment plant of an organized tannery industrial region in Istanbul, Turkey. Treatment of the wastewater was carried out by an electrochemical batch reactor equipped with two iron electrodes, which were connected parallel to each other. The oxidation process was studied for optimization of H 2 O 2 and the electricity consumptions were observed at different contact times under different pH conditions (3.0, 5.0 and 7.2). In each case, electricity consumption for decreased COD mass was estimated. In this process, COD was reduced by 60-70% within 10 min. By taking into consideration the local sewerage discharge limit, applicability of EF process for the tannery wastewaters was evaluated

Reduction of COD in wastewater from an organized tannery industrial region by Electro-Fenton process

Energy Technology Data Exchange (ETDEWEB)

Kurt, Ugur [Yildiz Technical University, Environmental Engineering Department, 34349 Istanbul (Turkey)]. E-mail: ukurt@yildiz.edu.tr; Apaydin, Omer [Yildiz Technical University, Environmental Engineering Department, 34349 Istanbul (Turkey)]. E-mail: apaydin@yildiz.edu.tr; Gonullu, M. Talha [Yildiz Technical University, Environmental Engineering Department, 34349 Istanbul (Turkey)]. E-mail: gonul@yildiz.edu.tr

2007-05-08

Advanced oxidation processes (AOPs) have led the way in the treatment of aqueous waste and are rapidly becoming the chosen technology for many applications. In this paper, COD reduction potential of leather tanning industry wastewaters by Electro-Fenton (EF) oxidation, as one of the AOPs, was experimentally evaluated. The wastewater sample was taken from an outlet of an equalization basin in a common treatment plant of an organized tannery industrial region in Istanbul, Turkey. Treatment of the wastewater was carried out by an electrochemical batch reactor equipped with two iron electrodes, which were connected parallel to each other. The oxidation process was studied for optimization of H{sub 2}O{sub 2} and the electricity consumptions were observed at different contact times under different pH conditions (3.0, 5.0 and 7.2). In each case, electricity consumption for decreased COD mass was estimated. In this process, COD was reduced by 60-70% within 10 min. By taking into consideration the local sewerage discharge limit, applicability of EF process for the tannery wastewaters was evaluated.

Relaxation of the electron spin in quantum dots via one- and two-phonon processes

International Nuclear Information System (INIS)

Calero, C.; Chudnovsky, E.M.; Garanin, D.A.

2007-01-01

We have studied direct and Raman processes of the decay of electron spin states in a quantum dot via radiation of phonons corresponding to elastic twists. Universal dependence of the spin relaxation rate on the strength and direction of the magnetic field has been obtained in terms of the electron gyromagnetic tensor and macroscopic elastic constants of the solid

Relaxation of the electron spin in quantum dots via one- and two-phonon processes

Energy Technology Data Exchange (ETDEWEB)

Calero, C. [Department of Physics and Astronomy, Lehman College, City University of New York, 250 Bedford Park Boulevard West, Bronx, NY 10468-1589 (United States)]. E-mail: carlos.calero-borrallo@lehman.cuny.edu; Chudnovsky, E.M. [Department of Physics and Astronomy, Lehman College, City University of New York, 250 Bedford Park Boulevard West, Bronx, NY 10468-1589 (United States); Garanin, D.A. [Department of Physics and Astronomy, Lehman College, City University of New York, 250 Bedford Park Boulevard West, Bronx, NY 10468-1589 (United States)

2007-09-15

We have studied direct and Raman processes of the decay of electron spin states in a quantum dot via radiation of phonons corresponding to elastic twists. Universal dependence of the spin relaxation rate on the strength and direction of the magnetic field has been obtained in terms of the electron gyromagnetic tensor and macroscopic elastic constants of the solid.

Quantum State Transfer from a Single Photon to a Distant Quantum-Dot Electron Spin

Science.gov (United States)

He, Yu; He, Yu-Ming; Wei, Yu-Jia; Jiang, Xiao; Chen, Kai; Lu, Chao-Yang; Pan, Jian-Wei; Schneider, Christian; Kamp, Martin; Höfling, Sven

2017-08-01

Quantum state transfer from flying photons to stationary matter qubits is an important element in the realization of quantum networks. Self-assembled semiconductor quantum dots provide a promising solid-state platform hosting both single photon and spin, with an inherent light-matter interface. Here, we develop a method to coherently and actively control the single-photon frequency bins in superposition using electro-optic modulators, and measure the spin-photon entanglement with a fidelity of 0.796 ±0.020 . Further, by Greenberger-Horne-Zeilinger-type state projection on the frequency, path, and polarization degrees of freedom of a single photon, we demonstrate quantum state transfer from a single photon to a single electron spin confined in an InGaAs quantum dot, separated by 5 m. The quantum state mapping from the photon's polarization to the electron's spin is demonstrated along three different axes on the Bloch sphere, with an average fidelity of 78.5%.

Optimizing electrocoagulation and electro-Fenton process for treating car wash wastewater

Directory of Open Access Journals (Sweden)

Seyyedali Mirshahghassemi

2017-02-01

Full Text Available Background: Car wash wastewater contains several contaminants such as organic matter, oil, grease, detergents and phosphates, all of which are harmful for the environment. In this study, the application of electrocoagulation (EC to treat car wash wastewater has been studied, and the operating parameters optimized. The electro-Fenton (EF for further contaminant removal was also investigated. Methods: In EC process, the effect of pH, current density, and the reaction time of the removal efficiency of chemical oxygen demand (COD, phosphate, and turbidity were investigated using the response surface methodology (RSM. The electrochemical cell consisted of four iron electrodes that were connected to a power supply using a monopolar arrangement. In the EF process, the effect of pH, reaction time, and hydrogen peroxide concentration on COD removal efficiency were probed. Results: The optimum pH, current density, and the reaction time for the EC process were 7.3, 4.2 mA cm-2 and 20.3 minutes, respectively. Under these conditions, the COD, phosphate, and turbidity removal percentages were 80.8%, 94.9% and 85.5%, respectively, and the specific energy consumption was 1.5 kWh m-3. For the EF process, the optimum pH, reaction time, current and hydrogen peroxide dosage were 3, 10 minutes, 2 A and 500 mg L-1, respectively. The EF showed higher COD removal efficiency (85.6% with a lower specific energy consumption (0.5 kWh m-3 and reaction time compared to the EC. Conclusion: This study shows that both EC and EF can effectively treat car wash wastewater with high removal efficiency within a short reaction time.

Neutron optics using transverse field neutron spin echo method

International Nuclear Information System (INIS)

Achiwa, Norio; Hino, Masahiro; Yamauchi, Yoshihiro; Takakura, Hiroyuki; Tasaki, Seiji; Akiyoshi, Tsunekazu; Ebisawa, Toru.

1993-01-01

A neutron spin echo (NSE) spectrometer with perpendicular magnetic field to the neutron scattering plane, using an iron yoke type electro-magnet has been developed. A combination of cold neutron guider, supermirror neutron polarizer of double reflection type and supermirror neutron analyser was adopted for the spectrometer. The first application of the NSE spectrometer to neutron optics by passing Larmor precessing neutrons through gas, solid and liquid materials of several different lengths which are inserted in one of the precession field have been examined. Preliminary NSE spectra of this sample geometry are discussed. (author)

Electron spin for classical information processing: a brief survey of spin-based logic devices, gates and circuits

International Nuclear Information System (INIS)

Bandyopadhyay, Supriyo; Cahay, Marc

2009-01-01

In electronics, information has been traditionally stored, processed and communicated using an electron's charge. This paradigm is increasingly turning out to be energy-inefficient, because movement of charge within an information processing device invariably causes current flow and an associated dissipation. Replacing 'charge' with the 'spin' of an electron to encode information may eliminate much of this dissipation and lead to more energy-efficient 'green electronics'. This realization has spurred significant research in spintronic devices and circuits where spin either directly acts as the physical variable for hosting information or augments the role of charge. In this review article, we discuss and elucidate some of these ideas, and highlight their strengths and weaknesses. Many of them can potentially reduce energy dissipation significantly, but unfortunately are error-prone and unreliable. Moreover, there are serious obstacles to their technological implementation that may be difficult to overcome in the near term. This review addresses three constructs: (1) single devices or binary switches that can be constituents of Boolean logic gates for digital information processing, (2) complete gates that are capable of performing specific Boolean logic operations, and (3) combinational circuits or architectures (equivalent to many gates working in unison) that are capable of performing universal computation. (topical review)

Spin-lattice relaxation of individual solid-state spins

Science.gov (United States)

Norambuena, A.; Muñoz, E.; Dinani, H. T.; Jarmola, A.; Maletinsky, P.; Budker, D.; Maze, J. R.

2018-03-01

Understanding the effect of vibrations on the relaxation process of individual spins is crucial for implementing nanosystems for quantum information and quantum metrology applications. In this work, we present a theoretical microscopic model to describe the spin-lattice relaxation of individual electronic spins associated to negatively charged nitrogen-vacancy centers in diamond, although our results can be extended to other spin-boson systems. Starting from a general spin-lattice interaction Hamiltonian, we provide a detailed description and solution of the quantum master equation of an electronic spin-one system coupled to a phononic bath in thermal equilibrium. Special attention is given to the dynamics of one-phonon processes below 1 K where our results agree with recent experimental findings and analytically describe the temperature and magnetic-field scaling. At higher temperatures, linear and second-order terms in the interaction Hamiltonian are considered and the temperature scaling is discussed for acoustic and quasilocalized phonons when appropriate. Our results, in addition to confirming a T5 temperature dependence of the longitudinal relaxation rate at higher temperatures, in agreement with experimental observations, provide a theoretical background for modeling the spin-lattice relaxation at a wide range of temperatures where different temperature scalings might be expected.

Vertical electro-absorption modulator design and its integration in a VCSEL

Science.gov (United States)

Marigo-Lombart, L.; Calvez, S.; Arnoult, A.; Thienpont, H.; Almuneau, G.; Panajotov, K.

2018-04-01

Electro-absorption modulators, either embedded in CMOS technology or integrated with a semiconductor laser, are of high interest for many applications such as optical communications, signal processing and 3D imaging. Recently, the integration of a surface-normal electro-absorption modulator into a vertical-cavity surface-emitting laser has been considered. In this paper we implement a simple quantum well electro-absorption model and design and optimize an asymmetric Fabry-Pérot semiconductor modulator while considering all physical properties within figures of merit. We also extend this model to account for the impact of temperature on the different parameters involved in the calculation of the absorption, such as refractive indices and exciton transition broadening. Two types of vertical modulator structures have been fabricated and experimentally characterized by reflectivity and photocurrent measurements demonstrating a very good agreement with our model. Finally, preliminary results of an electro-absorption modulator vertically integrated with a vertical-cavity surface-emitting laser device are presented, showing good modulation performances required for high speed communications.

Experimental Investigation – Magnetic Assisted Electro Discharge Machining

Science.gov (United States)

Kesava Reddy, Chirra; Manzoor Hussain, M.; Satyanarayana, S.; Krishna, M. V. S. Murali

2018-04-01

Emerging technology needs advanced machined parts with high strength and temperature resistance, high fatigue life at low production cost with good surface quality to fit into various industrial applications. Electro discharge machine is one of the extensively used machines to manufacture advanced machined parts which cannot be machined by other traditional machine with high precision and accuracy. Machining of DIN 17350-1.2080 (High Carbon High Chromium steel), using electro discharge machining has been discussed in this paper. In the present investigation an effort is made to use permanent magnet at various positions near the spark zone to improve surface quality of the machined surface. Taguchi methodology is used to obtain optimal choice for each machining parameter such as peak current, pulse duration, gap voltage and Servo reference voltage etc. Process parameters have significant influence on machining characteristics and surface finish. Improvement in surface finish is observed when process parameters are set at optimum condition under the influence of magnetic field at various positions.

Electrical detection of spin transport in lateral ferromagnet-semiconductor devices

Science.gov (United States)

Lou, Xiaohua

2007-03-01

A fully electrical scheme of spin injection, transport, and detection in a single ferromagnet-semiconductor structure has been a long-standing goal in the field of spintronics. In this talk, we report on an experimental demonstration of such a scheme. The devices are fabricated from epitaxial Fe/GaAs (100) heterostructures with highly doped GaAs as a Schottky tunnel barrier. A set of closely spaced Fe contacts on the top of an n-GaAs channel are used as spin injectors and detectors. Reference electrodes are placed at the far ends of the channel, allowing for non-local spin detection [1]. The electro-chemical potential of the detector is sensitive to the relative magnetizations of the injector and detector. In spin-valve measurements, a magnetic field is applied along the Fe easy axis to switch the relative magnetizations of injector and detector from parallel to antiparallel, resulting in a voltage jump that is proportional to the non-equilibrium spin polarization in the channel. A more rigorous test of electrical spin detection is the observation of the Hanle effect, in which an out-of-plane magnetic field is used to modulate and dephase the spin polarization in the channel. The magnitudes of the observed Hanle curves agree with the results of the spin-valve measurements. The dependence of the Hanle curves on temperature and contact separation is studied in detail and is consistent with a drift-diffusion model incorporating spin precession and relaxation. The spin polarization generated by spin injection (reverse bias at the injector) or spin accumulation (forward bias at the injector) is measured using the magneto-optical Kerr effect and is found to be in good agreement with the spin-dependent non-local voltage. Both the transport and optical measurements show a non-linear relationship between the bias voltage at the injector and the spin polarization in the channel. [1] M. Johnson and R. H. Silsbee, Phys. Rev. Lett. 55, 1790 (1985).

Spin-resolved electron waiting times in a quantum-dot spin valve

Science.gov (United States)

Tang, Gaomin; Xu, Fuming; Mi, Shuo; Wang, Jian

2018-04-01

We study the electronic waiting-time distributions (WTDs) in a noninteracting quantum-dot spin valve by varying spin polarization and the noncollinear angle between the magnetizations of the leads using the scattering matrix approach. Since the quantum-dot spin valve involves two channels (spin up and down) in both the incoming and outgoing channels, we study three different kinds of WTDs, which are two-channel WTD, spin-resolved single-channel WTD, and cross-channel WTD. We analyze the behaviors of WTDs in short times, correlated with the current behaviors for different spin polarizations and noncollinear angles. Cross-channel WTD reflects the correlation between two spin channels and can be used to characterize the spin-transfer torque process. We study the influence of the earlier detection on the subsequent detection from the perspective of cross-channel WTD, and define the influence degree quantity as the cumulative absolute difference between cross-channel WTDs and first-passage time distributions to quantitatively characterize the spin-flip process. We observe that influence degree versus spin-transfer torque for different noncollinear angles as well as different polarizations collapse into a single curve showing universal behaviors. This demonstrates that cross-channel WTDs can be a pathway to characterize spin correlation in spintronics system.

Influence of spin correlations in the transport properties of a double quantum dot system

Science.gov (United States)

Costa Ribeiro, Laercio; Hamad, Ignacio; Chiappe, Guillermo; Victoriano Anda, Enrique

2013-03-01

In this work we study the influence of spin correlations in the transport properties of a system consisting of two quantum dots (QDs) with high Coulomb interaction U which are interconnected through a chain of N non-interacting sites and individually coupled to two metallic leads. Using both the finite U slave boson mean field approach (FUSBMFA) and the Logarithmic-discretization-embedded-cluster approximation (LDECA) we studied the system in different regions of the parameter space for which we calculate many physical quantities, namely local density of states, conductance, total spin, spin correlations, in addition to the renormalization parameters associated with the FUSBMFA. The results reveled a very rich physical scenario which is manifested by at least two different Kondo regimes, the well-known spin s = 1/2 and some other type of Kondo effect which appears as a result of the coupling between the QDs and the non-interacting central sites. We also consider the possibility of accessing some kind of Kondo box effect due to the discrete nature of the central chain and study how this regime is affected by the magnetic interaction between the local spins of the QD's and by the interaction between these spins and the spins of the conduction electros in the leads.

A Real-Time Embedded Control System for Electro-Fused Magnesia Furnace

Directory of Open Access Journals (Sweden)

Fang Zheng

2013-01-01

Full Text Available Since smelting process of electro-fused magnesia furnace is a complicated process which has characteristics like complex operation conditions, strong nonlinearities, and strong couplings, traditional linear controller cannot control it very well. Advanced intelligent control strategy is a good solution to this kind of industrial process. However, advanced intelligent control strategy always involves huge programming task and hard debugging and maintaining problems. In this paper, a real-time embedded control system is proposed for the process control of electro-fused magnesia furnace based on intelligent control strategy and model-based design technology. As for hardware, an embedded controller based on an industrial Single Board Computer (SBC is developed to meet industrial field environment demands. As for software, a Linux based on Real-Time Application Interface (RTAI is used as the real-time kernel of the controller to improve its real-time performance. The embedded software platform is also modified to support generating embedded code automatically from Simulink/Stateflow models. Based on the proposed embedded control system, the intelligent embedded control software of electro-fused magnesium furnace can be directly generated from Simulink/Stateflow models. To validate the effectiveness of the proposed embedded control system, hardware-in-the-loop (HIL and industrial field experiments are both implemented. Experiments results show that the embedded control system works very well in both laboratory and industry environments.

Spin coating and plasma process for 2.5D integrated photonics on multilayer polymers

International Nuclear Information System (INIS)

Zebda, A.; Camberlein, L.; Beche, B.; Gaviot, E.; Beche, E.; Duval, D.; Zyss, J.; Jezequel, G.; Solal, F.; Godet, C.

2008-01-01

Polymer spin coating, surface plasma treatment and selective UV-lithography processes have been developed to realize 2.5D photonic micro-resonators, made of disk- or ring-shaped upper rib waveguides, using common polymers such as SU8 (biphenol A ether glycidyl), PS233 (polymeric silane) and SOG (siloxane Spin on Glass). Both oxygen and argon plasma treatments, applied to PS233 and SOG before spin-coating the SU8, improve substantially the grip of multilayer devices (SU8 / PS233 or SU8 / SOG). Surface energy components derived from contact angle measurements have been used to optimize the processing conditions. In such integrated photonic devices, the both single-electromagnetic-modes called transverse electric (TE 00 ) and transverse magnetic (TM 00 ) have been excited in a SU8 micro-disk, with a single mode propagation strongly localized near the edge of the disk (i.e. the so called whispering gallery modes)

Electro pneumatic trainer embedded with programmable integrated circuit (PIC) microcontroller and graphical user interface platform for aviation industries training purposes

Science.gov (United States)

Burhan, I.; Azman, A. A.; Othman, R.

2016-10-01

An electro pneumatic trainer embedded with programmable integrated circuit (PIC) microcontroller and Visual Basic (VB) platform is fabricated as a supporting tool to existing teaching and learning process, and to achieve the objectives and learning outcomes towards enhancing the student's knowledge and hands-on skill, especially in electro pneumatic devices. The existing learning process for electro pneumatic courses conducted in the classroom does not emphasize on simulation and complex practical aspects. VB is used as the platform for graphical user interface (GUI) while PIC as the interface circuit between the GUI and hardware of electro pneumatic apparatus. Fabrication of electro pneumatic trainer interfacing between PIC and VB has been designed and improved by involving multiple types of electro pneumatic apparatus such as linear drive, air motor, semi rotary motor, double acting cylinder and single acting cylinder. Newly fabricated electro pneumatic trainer microcontroller interface can be programmed and re-programmed for numerous combination of tasks. Based on the survey to 175 student participants, 97% of the respondents agreed that the newly fabricated trainer is user friendly, safe and attractive, and 96.8% of the respondents strongly agreed that there is improvement in knowledge development and also hands-on skill in their learning process. Furthermore, the Lab Practical Evaluation record has indicated that the respondents have improved their academic performance (hands-on skills) by an average of 23.5%.

Cyclic voltammetric study of electro-oxidation of methanol on platinum electrode in acidic and neutral media

International Nuclear Information System (INIS)

Khan, A.S.A.; Ahmed, R.; Mirza, M.L.

2007-01-01

The electro-oxidation of methanol on electrochemically treated platinum foil was investigated in acidic and neutral media for comparison of cyclic voltammetric characteristics and elucidation of mechanism of electro-oxidation of methanol. The surface area and roughness factor of platinum electrode was calculated. The electro-oxidation of mathanol is an irreversible process giving. anodic peaks in both anodic and cathodic sweep. The characteristic peaks of electrooxidation of methanol appeared at almost the same potential region in both acidic and neutral media. In neutral medium, certain additional cathodic/anodic peaks appeared which were confirmed to arise by the reduction/oxidation of hydrogen ions. The exchange current density and heterogeneous electron transfer rate constant was higher in neutral medium as. compared with acidic medium. The thermodynamic parameters delta H, delta S, and delta G/sub 298/ were calculated. The values of delta H and delta G/sub 298/were positive which indicated that the process of electro-oxidation of methanol is an endothermic and nonspontaneous. The mechanism of electro-oxidation of methanol was same in both acidic and neutral media involving the formation of various adsorbed intermediate species through dissociative adsorption steps leading to the formation of Co adsorbed radicals, which are removed. during interaction with adsorbed hydrous oxides provided by the oxidation of adsorbed water molecules. The higher rate of electro-oxidation of methanol in neutral medium was interpreted in the tight of electrochemical mechanism and was attributed to the presence of comparatively small amount of hydrogen ions only along the surface of working electrode, which are produced during electro-oxidation of methanol. (author)

Muon spin rotation and other microscopic probes of spin-glass dynamics

International Nuclear Information System (INIS)

MacLaughlin, D.E.

1980-01-01

A number of different microscopic probe techniques have been employed to investigate the onset of the spin-glass state in dilute magnetic alloys. Among these are Moessbauer-effect spectroscopy, neutron scattering, ESR of the impurity spins, host NMR and, most recently, muon spin rotation and depolarization. Spin probes yield information on the microscopic static and dynamic behavior of the impurity spins, and give insight into both the spin freezing process and the nature of low-lying excitations in the ordered state. Microscopic probe experiments in spin glasses are surveyed, and the unique advantages of muon studies are emphasized

Robust Position Control of Electro-mechanical Systems

OpenAIRE

Rong Mei; Mou Chen

2013-01-01

In this work, the robust position control scheme is proposed for the electro-mechanical system using the disturbance observer and backstepping control method. To the external unknown load of the electro-mechanical system, the nonlinear disturbance observer is given to estimate the external unknown load. Combining the output of the developed nonlinear disturbance observer with backstepping technology, the robust position control scheme is proposed for the electro-mechanical system. The stabili...

On the manufacturing of a gas turbine engine part through metal spinning process

Science.gov (United States)

Hassanin, A. El; Astarita, A.; Scherillo, F.; Velotti, C.; Squillace, A.; Liguori, A.

2018-05-01

Metal spinning processes represents an interesting alternative to traditional sheet metal forming processes in several industrial contexts, such as automotive and aerospace. In this work, the production of a combustion chamber liner top prototype using AISI 304L stainless steel is proposed, in order to evaluate the process feasibility for the required part geometry. The prototypes production was carried out using a two-stage semiautomatic spinning process. The effects in terms of wall thickness reduction were investigated. Using optical microscopy and Scanning Electron Microscopy (SEM) techniques, the microstructural behavior of the metal subjected to the forming process was investigated, while for an evaluation of the influence on the mechanical properties Vickers micro-indentation tests were performed. The main result of the process, as observed from all the investigation techniques adopted, is the formation of strain induced martensite due to the severe plastic deformation and cold reduction of the material, ranging in this case from 30% to 50%. In some areas of the part section, some rips indicating an excessive tensile stress were also detected.

The combined removal of methyl mercaptan and hydrogen sulfide via an electro-reactor process using a low concentration of continuously regenerable Ag(II) active catalyst

International Nuclear Information System (INIS)

Muthuraman, Govindan; Chung, Sang Joon; Moon, Il Shik

2011-01-01

Highlights: → Simultaneous removal of H 2 S and CH 3 SH was achieved at electro-reactor. → Active catalyst Ag(II) perpetually regenerated in HNO 3 medium by electrochemical cell. → CH 3 SH destruction follows two reaction pathways. → H 2 S induced destruction of CH 3 SH has identified. → Low concentration of active Ag(II) (12.5 x 10 -4 mol L -1 ) is enough for complete destruction. - Abstract: In this study, an electrocatalytic wet scrubbing process was developed for the simultaneous removal of synthetic odorous gases namely, methyl mercaptan (CH 3 SH) and hydrogen sulfide (H 2 S). The initial process consists of the absorption of CH 3 SH and H 2 S gases by an absorbing solution, followed by their mediated electrochemical oxidation using a low concentration of active Ag(II) in 6 M HNO 3 . Experiments were conducted under different reaction conditions, such as CH 3 SH and H 2 S loadings, active Ag(II) concentrations and molar flow rates. The cyclic voltammetry for the oxidation of CH 3 SH corroborated the electro-reactor results, in that the silver in the 6 M HNO 3 reaction solution significantly influences the oxidation of CH 3 SH. At a low active Ag(II) concentration of 0.0012 M, the CH 3 SH removal experiments demonstrated that the CH 3 SH degradation was steady, with 100% removal at a CH 3 SH loading of 5 g m -3 h -1 . The electro-reactor and cyclic voltammetry results indicated that the removal of H 2 S (100%) follows a mediated electrocatalytic oxidation reaction. The simultaneous removal of 100% of the CH 3 SH and H 2 S was achieved, even with a very low active Ag(II) concentration (0.0012 M), as a result of the high efficiency of the Ag(II). The parallel cyclic voltammetry results demonstrated that a process of simultaneous destruction of both CH 3 SH and H 2 S follows an H 2 S influenced mediated electrocatalytic oxidation. The use of a very low concentration of the Ag(II) mediator during the electro-reactor process is promising for the complete

Electro-volatilization of ruthenium in nitric medium: influences of ruthenium species nature and models solutions composition

International Nuclear Information System (INIS)

Mousset, F.

2004-12-01

Ruthenium is one of the fission products in the reprocessing of irradiated fuels that requires a specific processing management. Its elimination, upstream by the PUREX process, has been considered. A process, called electro-volatilization, which take advantage of the RuO 4 volatility, has been optimised in the present study. It consists in a continuous electrolysis of ruthenium solutions in order to generate RuO 4 species that is volatilized and easily trapped. This process goes to satisfying ruthenium elimination yields with RuNO(NO 3 ) 3 (H 2 O) 2 synthetic solutions but not with fuel dissolution solutions. Consequently, this work consisted in the speciation studies of dissolved ruthenium species were carried out by simulating fuel solutions produced by hot acid attack of several ruthenium compounds (Ru(0), RuO 2 ,xH 2 O, polymetallic alloy). In parallel with dissolution kinetic studies, the determination of dissolved species was performed using voltammetry, spectrometry and spectro-electrochemistry. The results showed the co-existence of Ru(IV) and RuNO(NO 2 ) 2 (H 2 O) 3 . Although these species are different from synthetic RuNO(NO 3 ) 3 (H 2 O) 2 , their electro-oxidation behaviour are similar. The electro-volatilization tests of these dissolution solutions yielded to comparable results as the synthetic RuNO(NO 3 ) 3 (H 2 O) 2 solutions. Then, complexity increase of models solutions was performed by in-situ generation of nitrous acid during ruthenium dissolution. Nitrous acid showed a catalytic effect on ruthenium dissolution. Its presence goes to quasi exclusively RuNO(NO 2 ) 2 (H 2 O) 3 species. It is also responsible of the strong n-bond formation between Ru 2+ and NO + . In addition, it has been shown that its reducing action on RuO 4 hinders the electro-volatilization process. Mn 2+ and Ce 3+ cations also reveal, but to a lesser extent, an electro-eater behaviour as well as Pu 4+ and Cr 3+ according to the thermodynamics data. These results allow one to

Device to control the desalination and dehydration process for petroleum in an electro-dehydrator

Energy Technology Data Exchange (ETDEWEB)

Kusowskii, B I; Pawlow, N I; Matiitschenko, A P; Sacharow, S A; Kirilin, A F

1976-01-22

The invention deals with a device to control the desalination and dehydration processes for petroleum in electro-dehydrators. In the latter, the water-petroleum emulsion introduced is separated by an electric field into petroleum and salt water. Regulation of the dehydration and desalination process by means of the current difference of two circuits in the emulgator, in which this difference controls the controlling unit of a regulating valve, via which salt water and dirt remains are removed from the dehydrator, is known. This device, however, is not immune to disturbance, as when changing the water content of the emulsion, spark-overs may occur between one electrode and the surface of the separated salt water. This disturbance is removed according to the invention in that the abrupt changes of current prior to the spark-over cause a forcibly increased through-flow amount of discharging salt water and dirt remains for a certain time and thus prevent the full formation of an electric spark-over disturbing the operation of the dehydrator.

Synthesis of Y2O3-ZrO2-SiO2 composite coatings on carbon fiber reinforced resin matrix composite by an electro-plasma process

Science.gov (United States)

Zhang, Yuping; Lin, Xiang; Chen, Weiwei; Cheng, Huanwu; Wang, Lu

2016-05-01

In the present paper the Y2O3-ZrO2-SiO2 composite coating was successfully synthesized on carbon fiber reinforced resin matrix composite by an electro-plasma process. The deposition process, microstructures and oxidation resistance of the coatings with different SiO2 concentrations were systematically investigated. A relatively dense microstructure was observed for the Y2O3-ZrO2-SiO2 composite coating with the SiO2 concentration above 5 g/L. The coating exhibited very good oxidation resistance at 1273 K with the mass loss rate as low as ∼30 wt.%, compared to 100 wt.% of the substrate. The formation of the ceramic composites was discussed in detail based on the electrochemical mechanism and the deposition dynamics in order to explain the effect of the plasma discharge. We believe that the electro-plasma process will find wide applications in preparing ceramics and coatings in industries.

Electro-chemo-hydro-mechanical coupling in clayey media; Couplage electro-chimio-hydro-mecaniques dans les milieux argileux

Energy Technology Data Exchange (ETDEWEB)

Lemaire, Th

2004-12-15

The aim of this study is to understand coupled phenomena that occur in swelling porous materials like clays. Electro-chemo-hydro-mechanical contributions are taken into account to analyze transfers in such minerals. In a first part, a general discussion is proposed to introduce mineralogical and physico- chemical considerations of clayey media. An important objective of this chapter is to show the crucial role of the microstructure. In a second part is presented an imbibition test in a MX80 bentonite powder. The hydraulic diffusivity versus water content curve's decrease is explained thanks to a double porosity model that shows the progressive collapse of meso-pores due to swelling effects at the micro-scale. Thus a multi-scale analysis is necessary to well describe clayey media behaviour. The third chapter exposes such a multi-scale modelling (periodic homogenization). It is based on the double-layer theory and introduces an innovative concept of virtual electrolyte solution. First numerical results are given in a simple geometry (parallel platelets). In the next part are proposed numerical simulations of two kinds: response of the system to a chemical gradient and simulation of electro-osmosis. The end of this chapter puts into relief the necessity to integrate pH effects in the model. In the last part, chemical surface exchanges are incorporated in the modelling to understand pH and ionic force roles in electro-osmotic process. (author)

Nitrate removal by electro-bioremediation technology in Korean soil

International Nuclear Information System (INIS)

Choi, Jeong-Hee; Maruthamuthu, Sundaram; Lee, Hyun-Goo; Ha, Tae-Hyun; Bae, Jeong-Hyo

2009-01-01

The nitrate concentration of surface has become a serious concern in agricultural industry through out the world. In the present study, nitrate was removed in the soil by employing electro-bioremediation, a hybrid technology of bioremediation and electrokinetics. The abundance of Bacillus spp. as nitrate reducing bacteria were isolated and identified from the soil sample collected from a greenhouse at Jinju City of Gyengsangnamdo, South Korea. The nitrate reducing bacterial species were identified by 16 s RNA sequencing technique. The efficiency of bacterial isolates on nitrate removal in broth was tested. The experiment was conducted in an electrokinetic (EK) cell by applying 20 V across the electrodes. The nitrate reducing bacteria (Bacillus spp.) were inoculated in the soil for nitrate removal process by the addition of necessary nutrient. The influence of nitrate reducers on electrokinetic process was also studied. The concentration of nitrate at anodic area of soil was higher when compared to cathode in electrokinetic system, while adding bacteria in EK (EK + bio) system, the nitrate concentration was almost nil in all the area of soil. The bacteria supplies electron from organic degradation (humic substances) and enhances NO 3 - reduction (denitrification). Experimental results showed that the electro-bio kinetic process viz. electroosmosis and physiological activity of bacteria reduced nitrate in soil environment effectively. Involvement of Bacillus spp. on nitrification was controlled by electrokinetics at cathode area by reduction of ammonium ions to nitrogen gas. The excellence of the combined electro-bio kinetics technology on nitrate removal is discussed.

Electro-precipitation of magnetite nanoparticles: an electrochemical study

OpenAIRE

Ibrahim, Mona; Groenen-Serrano, Karine; Noé, Laure; Garcia, Cécile; Verelst, Marc

2009-01-01

Nanoparticles of magnetites (Fe3O4) are synthesized with a new process based on electro-precipitation in ethanol medium. A mechanism pathway is proposed consisting of a Fe(OH)3 precipitation followed by the reduction of iron hydroxide to magnetite in the presence of hydroxyl ions which are enerated at the cathode.

Electro-active sensor, method for constructing the same; apparatus and circuitry for detection of electro-active species

Science.gov (United States)

Buehler, Martin (Inventor)

2009-01-01

An electro-active sensor includes a nonconductive platform with a first electrode set attached with a first side of a nonconductive platform. The first electrode set serves as an electrochemical cell that may be utilized to detect electro-active species in solution. A plurality of electrode sets and a variety of additional electrochemical cells and sensors may be attached with the nonconductive platform. The present invention also includes a method for constructing the aforementioned electro-active sensor. Additionally, an apparatus for detection and observation is disclosed, where the apparatus includes a sealable chamber for insertion of a portion of an electro-active sensor. The apparatus allows for monitoring and detection activities. Allowing for control of attached cells and sensors, a dual-mode circuitry is also disclosed. The dual-mode circuitry includes a switch, allowing the circuitry to be switched from a potentiostat to a galvanostat mode.

Giant quadratic electro-optical effect during polarization switching in ultrathin ferroelectric polymer films

Energy Technology Data Exchange (ETDEWEB)

Blinov, L. M., E-mail: lev39blinov@gmail.com; Lazarev, V V; Palto, S P; Yudin, S G [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

2012-04-15

The low-frequency quadratic electro-optical effect with a maximum electro-optical coefficient of g = 8 Multiplication-Sign 10{sup -19} m{sup 2}/V{sup 2} (i.e., four orders of magnitude greater than the standard high-frequency value) has been studied in thin films of ferroelectric polymer PVDF(70%)-TrFE(30%). The observed effect is related to the process of spontaneous polarization switching, during which the electron oscillators of C-F and C-H dipole groups rotate to become parallel to the applied field. As a result, the ellipsoid of the refractive index exhibits narrowing in the direction perpendicular to the field. The field dependence of the electro-optical coefficient g correlates with that of the apparent dielectric permittivity, which can be introduced under the condition of ferroelectric polarization switching. The observed electro-optical effect strongly decreases when the frequency increases up to several hundred hertz. The temperature dependence of the effect exhibits clearly pronounced hysteresis in the region of the ferroelectric phase transition.

Rational design of organic electro-optic materials

International Nuclear Information System (INIS)

Dalton, L R

2003-01-01

Quantum mechanical calculations are used to optimize the molecular first hyperpolarizability of organic chromophores and statistical mechanical calculations are used to optimize the translation of molecular hyperpolarizability to macroscopic electro-optic activity (to values of greater than 100 pm V -1 at telecommunications wavelengths). Macroscopic material architectures are implemented exploiting new concepts in nanoscale architectural engineering. Multi-chromophore-containing dendrimers and dendronized polymers not only permit optimization of electro-optic activity but also of auxiliary properties including optical loss (both absorption and scattering), thermal and photochemical stability and processability. New reactive ion etching and photolithographic techniques permit the fabrication of three-dimensional optical circuitry and the integration of that circuitry with semiconductor very-large-scale integration electronics and silica fibre optics. Electro-optic devices have been fabricated exploiting stripline, cascaded prism and microresonator device structures. Sub-1 V drive voltages and operational bandwidths of greater than 100 GHz have been demonstrated. Both single-and double-ring microresonators have been fabricated for applications such as active wavelength division multiplexing. Free spectral range values of 1 THz and per channel modulation bandwidths of 15 GHz have been realized permitting single-chip data rates of 500 Gb s -1 . Other demonstrated devices include phased array radar, optical gyroscopes, acoustic spectrum analysers, ultrafast analog/digital converters and ultrahigh bandwidth signal generators. (topical review)

Enhanced methanol electro-oxidation activity of Pt/MWCNTs electro-catalyst using manganese oxide deposited on MWCNTs

International Nuclear Information System (INIS)

Nouralishahi, Amideddin; Khodadadi, Abbas Ali; Mortazavi, Yadollah; Rashidi, Alimorad; Choolaei, Mohammadmehdi

2014-01-01

Highlights: • Promoting effects of manganese oxide (MnO x ) on methanol electro-oxidation over Pt/MWCNTs are studied. • 3.3 times higher activity and improved stability are observed on Pt/MnO x -MWCNTs in MOR. • Both hydrogen spill over and bi-functional mechanism are facilitated in presence of MnO x . • MnO x significantly enhances electrochemical active surface area and dispersion of Pt nanoparticles. • Proton conductivity of electrocatalyst layer is improved upon MnO x incorporation. - Abstract: Electro-oxidation of methanol on platinum nanoparticles supported on a nanocomposite of manganese oxide (MnO x ) and multi-wall carbon nanotubes (MWCNTs) is investigated. The morphology, structure, and chemical composition of the electro-catalysts are characterized by TEM, XRD, EDS, TGA, and H 2 -TPR. The electro-catalytic properties of electrodes are examined by cyclic voltammetry, CO-stripping, electrochemical impedance spectroscopy (EIS), and linear sweep voltammetry (LSV). Compared to Pt/MWCNTs, the Pt/MnO x -MWCNTs electro-catalyst exhibits about 3.3 times higher forward peak current density, during cyclic voltammetry, and 4.6 times higher exchange current density in methanol electro-oxidation reaction. In addition, deposition of manganese oxide onto MWCNTs dramatically increases the electrochemical active surface area from 29.7 for Pt/MWCNTs to 89.4 m 2 g −1 Pt for Pt/MnO x -MWCNTs. The results of long-term cyclic voltammetry show superior stability of Pt nanoparticles upon addition of manganese oxide to the support. Furthermore, the kinetics of formation of the chemisorbed OH groups improves upon manganese oxide incorporation. This leads to a lower onset potential of CO ads oxidation on Pt/MnO x -MWCNTs than on Pt/MWCNTs

Assessment of Spacecraft Operational Status Using Electro-Optical Predictive Techniques

Science.gov (United States)

2010-09-01

panel appendages, may require enhanced preflight characterization processes to support monitoring by passive, remote, nonimaging optical sensors...observing and characterizing key spacecraft features. The simulation results are based on electro-optical signatures apparent to nonimaging sensors, along...and communication equipment, may require enhanced preflight characterization processes to support monitoring by passive, remote, nonimaging optical

Confinement dependence of electro-catalysts for hydrogen evolution from water splitting

Directory of Open Access Journals (Sweden)

Mikaela Lindgren

2014-02-01

Full Text Available Density functional theory is utilized to articulate a particular generic deconstruction of the electrode/electro-catalyst assembly for the cathode process during water splitting. A computational model was designed to determine how alloying elements control the fraction of H2 released during zirconium oxidation by water relative to the amount of hydrogen picked up by the corroding alloy. This model is utilized to determine the efficiencies of transition metals decorated with hydroxide interfaces in facilitating the electro-catalytic hydrogen evolution reaction. A computational strategy is developed to select an electro-catalyst for hydrogen evolution (HE, where the choice of a transition metal catalyst is guided by the confining environment. The latter may be recast into a nominal pressure experienced by the evolving H2 molecule. We arrived at a novel perspective on the uniqueness of oxide supported atomic Pt as a HE catalyst under ambient conditions.

Microscopic studies of nonlocal spin dynamics and spin transport (invited)

Energy Technology Data Exchange (ETDEWEB)

Adur, Rohan; Du, Chunhui; Cardellino, Jeremy; Scozzaro, Nicolas; Wolfe, Christopher S.; Wang, Hailong; Herman, Michael; Bhallamudi, Vidya P.; Pelekhov, Denis V.; Yang, Fengyuan; Hammel, P. Chris, E-mail: hammel@physics.osu.edu [Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States)

2015-05-07

Understanding the behavior of spins coupling across interfaces in the study of spin current generation and transport is a fundamental challenge that is important for spintronics applications. The transfer of spin angular momentum from a ferromagnet into an adjacent normal material as a consequence of the precession of the magnetization of the ferromagnet is a process known as spin pumping. We find that, in certain circumstances, the insertion of an intervening normal metal can enhance spin pumping between an excited ferromagnetic magnetization and a normal metal layer as a consequence of improved spin conductance matching. We have studied this using inverse spin Hall effect and enhanced damping measurements. Scanned probe magnetic resonance techniques are a complementary tool in this context offering high resolution magnetic resonance imaging, localized spin excitation, and direct measurement of spin lifetimes or damping. Localized magnetic resonance studies of size-dependent spin dynamics in the absence of lithographic confinement in both ferromagnets and paramagnets reveal the close relationship between spin transport and spin lifetime at microscopic length scales. Finally, detection of ferromagnetic resonance of a ferromagnetic film using the photoluminescence of nitrogen vacancy spins in neighboring nanodiamonds demonstrates long-range spin transport between insulating materials, indicating the complexity and generality of spin transport in diverse, spatially separated, material systems.

Microscopic studies of nonlocal spin dynamics and spin transport (invited)

Science.gov (United States)

Adur, Rohan; Du, Chunhui; Cardellino, Jeremy; Scozzaro, Nicolas; Wolfe, Christopher S.; Wang, Hailong; Herman, Michael; Bhallamudi, Vidya P.; Pelekhov, Denis V.; Yang, Fengyuan; Hammel, P. Chris

2015-05-01

Understanding the behavior of spins coupling across interfaces in the study of spin current generation and transport is a fundamental challenge that is important for spintronics applications. The transfer of spin angular momentum from a ferromagnet into an adjacent normal material as a consequence of the precession of the magnetization of the ferromagnet is a process known as spin pumping. We find that, in certain circumstances, the insertion of an intervening normal metal can enhance spin pumping between an excited ferromagnetic magnetization and a normal metal layer as a consequence of improved spin conductance matching. We have studied this using inverse spin Hall effect and enhanced damping measurements. Scanned probe magnetic resonance techniques are a complementary tool in this context offering high resolution magnetic resonance imaging, localized spin excitation, and direct measurement of spin lifetimes or damping. Localized magnetic resonance studies of size-dependent spin dynamics in the absence of lithographic confinement in both ferromagnets and paramagnets reveal the close relationship between spin transport and spin lifetime at microscopic length scales. Finally, detection of ferromagnetic resonance of a ferromagnetic film using the photoluminescence of nitrogen vacancy spins in neighboring nanodiamonds demonstrates long-range spin transport between insulating materials, indicating the complexity and generality of spin transport in diverse, spatially separated, material systems.

Microscopic studies of nonlocal spin dynamics and spin transport (invited)

International Nuclear Information System (INIS)

Adur, Rohan; Du, Chunhui; Cardellino, Jeremy; Scozzaro, Nicolas; Wolfe, Christopher S.; Wang, Hailong; Herman, Michael; Bhallamudi, Vidya P.; Pelekhov, Denis V.; Yang, Fengyuan; Hammel, P. Chris

2015-01-01

Understanding the behavior of spins coupling across interfaces in the study of spin current generation and transport is a fundamental challenge that is important for spintronics applications. The transfer of spin angular momentum from a ferromagnet into an adjacent normal material as a consequence of the precession of the magnetization of the ferromagnet is a process known as spin pumping. We find that, in certain circumstances, the insertion of an intervening normal metal can enhance spin pumping between an excited ferromagnetic magnetization and a normal metal layer as a consequence of improved spin conductance matching. We have studied this using inverse spin Hall effect and enhanced damping measurements. Scanned probe magnetic resonance techniques are a complementary tool in this context offering high resolution magnetic resonance imaging, localized spin excitation, and direct measurement of spin lifetimes or damping. Localized magnetic resonance studies of size-dependent spin dynamics in the absence of lithographic confinement in both ferromagnets and paramagnets reveal the close relationship between spin transport and spin lifetime at microscopic length scales. Finally, detection of ferromagnetic resonance of a ferromagnetic film using the photoluminescence of nitrogen vacancy spins in neighboring nanodiamonds demonstrates long-range spin transport between insulating materials, indicating the complexity and generality of spin transport in diverse, spatially separated, material systems

A microbial electro-fenton cell for removing carbamazepine in wastewater with electricity output.

Science.gov (United States)

Wang, Wei; Lu, Yaobin; Luo, Haiping; Liu, Guangli; Zhang, Renduo; Jin, Song

2018-03-27

High electrical energy is required for the electro-Fenton process to remove pharmaceuticals and personal care products (PPCPs) in wastewater. The aim of this study was to develop a novel and more cost-effective process, specifically a microbial electro-Fenton cell (MeFC), for treating PPCPs in wastewater. Acetylene black was selected as the catalyst for H 2 O 2 electrogeneration and Fe-Mn binary oxide for hydroxyl radical production. In addition to lowering energy needs, the MeFC produced a maximum power density of 112 ± 11 mW/m 2 with 1 g/L acetate as a representative substrate and 10 mg/L carbamazepine (CBZ) as a typical PPCP. Comparing with electro-Fenton process, the CBZ removal in the MeFC was 38% higher within 24 h operation (90% vs. 62%). Furthermore, the CBZ removal rate in the MeFC was 10-100 times faster than that in other biological treatment processes. Such enhanced degradation of CBZ in the MeFC was attributed to the synergistic reactions between radical oxidation of CBZ and biodegradation of degradative intermediates. The MeFC provides a promising method to remove PPCPs from wastewater coupling with efficient removal of other biodegradable organics. Copyright © 2018 Elsevier Ltd. All rights reserved.

Spin torque nanooscillators: new applications in information processing

Science.gov (United States)

Macia, Ferran; Kent, Andrew D.; Hoppensteadt, Frank C.

2013-03-01

Nanonometer scale electrical contacts to ferromagnetic thin films (STNOs) can provide sufficient current densities to excite magnetic-moment dynamics resulting in emission of short wave-length spin waves. We discuss several applications of spin-wave patterns created from STNOs and their interaction with background oscillations. We review how to encode information in STNOs signals -modulating their amplitude, frequency or phase - and stability against noise. We first model arrays of STNOs in extended ferromagnetic thin films and define conditions to control spin-waves emission directions. We also study arrays of oscillators in patterned ferromagnetic thin films and we put forward a method to build an STNO lookup tables or an STNO based network analyzer. Using spin waves complements digital semiconductor technologies and offers new possibilities for increased memory capacity and computation performance. This work was supported by Marie Curie IOF 253214 and by ARO MURI Grant No. W911NF-08-1-0317 and NSF Grant No. ECS 07- 25280.

Measuring gas temperature during spin-exchange optical pumping process

Science.gov (United States)

Normand, E.; Jiang, C. Y.; Brown, D. R.; Robertson, L.; Crow, L.; Tong, X.

2016-04-01

The gas temperature inside a Spin-Exchange Optical Pumping (SEOP) laser-pumping polarized 3He cell has long been a mystery. Different experimental methods were employed to measure this temperature but all were based on either modelling or indirect measurement. To date there has not been any direct experimental measurement of this quantity. Here we present the first direct measurement using neutron transmission to accurately determine the number density of 3He, the temperature is obtained using the ideal gas law. Our result showed a surprisingly high gas temperature of 380°C, compared to the 245°C of the 3He cell wall temperature and 178°C of the optical pumping oven temperature. This experiment result may be used to further investigate the unsolved puzzle of the "X-factor" in the SEOP process which places an upper bound to the 3He polarization that can be achieved. Additional spin relaxation mechanisms might exist due to the high gas temperature, which could explain the origin of the X-factor.

A highly energy-efficient flow-through electro-Fenton process for organic pollutants degradation

International Nuclear Information System (INIS)

Ma, Liang; Zhou, Minghua; Ren, Gengbo; Yang, Weilu; Liang, Liang

2016-01-01

Highlights: • A highly energy-efficient flow-through electro-Fenton reactor was designed. • It had high H 2 O 2 yield and low energy consumption for organic pollutants degradation. • The effect of operational parameters was optimized and possible process mechanism was studied. • The novel system performed wide practicability and potential for organic pollutants degradation. - Abstract: A highly energy-efficient flow-through Electro-Fenton (E-Fenton) reactor for oxidation of methylene blue (MB) from aqueous solution was designed using a perforated DSA as anode and the graphite felt modified by carbon black and polytetrafluoroethylene (PTFE) as cathode for the in situ generation of H 2 O 2 . The modified cathode had a high H 2 O 2 production with low energy consumption, which was characterized by scanning electron microscopy (SEM), nitrogen adsorption-desorption study and contact angle. The flow-through E-Fenton system was compared to the flow-by and regular one, and confirmed to be best on MB removal and TOC degradation. The operational parameters such as current density, pH, Fe 2+ concentration and flow rate were optimized. The MB and TOC removal efficiency of the effluents could keep above 90% and 50%, respectively, and the energy consumption was 23.0 kWh/kgTOC at the current density of 50 mA, pH 3, 0.3 mM Fe 2+ , and the flow rate of 7 mL/min. ·OH was proved to be the main oxidizing species in this system. After 5 times operation, the system, especially cathode, still showed good stability. Five more organic pollutants including orange II (OG), tartrazine, acetylsalicylic acid (ASA), tetracycline (TC) and 2,4-dichlorophen (2,4-DCP) were investigated and the electric energy consumption (EEC) was compared with literatures. All results demonstrated that this flow-through E-Fenton system was energy-efficient and potential for degradation of organic pollutants.

SPINning parallel systems software

International Nuclear Information System (INIS)

Matlin, O.S.; Lusk, E.; McCune, W.

2002-01-01

We describe our experiences in using Spin to verify parts of the Multi Purpose Daemon (MPD) parallel process management system. MPD is a distributed collection of processes connected by Unix network sockets. MPD is dynamic processes and connections among them are created and destroyed as MPD is initialized, runs user processes, recovers from faults, and terminates. This dynamic nature is easily expressible in the Spin/Promela framework but poses performance and scalability challenges. We present here the results of expressing some of the parallel algorithms of MPD and executing both simulation and verification runs with Spin

Thermal management evaluation of the complex electro-optical system

Directory of Open Access Journals (Sweden)

Nijemčević Srećko S.

2017-01-01

Full Text Available The thermal management of a complex electro-optical system aimed for outdoor application is challenging task due to the requirement of having an air-sealed enclosure, harsh working environment, and an additional thermal load generated by sunlight. It is essential to consider the effect of heating loads in the system components, as well as the internal temperature distribution, that can have influence on the system life expectancy, operational readiness and parameters, and possibility for catastrophic failure. The main objective of this paper is to analyze internal temperature distribution and evaluate its influence on system component operation capability. The electro-optical system simplified model was defined and related thermal balance simulation model based on Solid Works thermal analysis module was set and applied for temperature distribution calculation. Various outdoor environment scenarios were compared to evaluate system temperature distribution and evaluate its influence on system operation, reliability, and life time in application environment. This work was done during the design process as a part of the electro-optical system optimization. The results show that temperature distribution will not be cause for catastrophic failure and malfunction operation during operation in the expected environment.

Selection of a Commercial Anode Oxide Coating for Electro-oxidation of Cyanide

Directory of Open Access Journals (Sweden)

Lanza Marcos Roberto V.

2002-01-01

Full Text Available This paper presents a study of the performance of two commercial dimensionally stable anode (DSA® oxide coatings in the electrochemical process for cyanide oxidation. The coatings studied were 70TiO2/30RuO2 and 55Ta2O5/45IrO2, on Ti substrate. The efficiency of both materials in the electro-oxidation of free cyanide was compared using linear voltammetry and electrolysis at constant potential. The 70TiO2/30RuO2 electrode shows a better performance in the electro-oxidation of free cyanide.

Field-controllable Spin-Hall Effect of Light in Optical Crystals: A Conoscopic Mueller Matrix Analysis.

Science.gov (United States)

Samlan, C T; Viswanathan, Nirmal K

2018-01-31

Electric-field applied perpendicular to the direction of propagation of paraxial beam through an optical crystal dynamically modifies the spin-orbit interaction (SOI), leading to the demonstration of controllable spin-Hall effect of light (SHEL). The electro- and piezo-optic effects of the crystal modifies the radially symmetric spatial variation in the fast-axis orientation of the crystal, resulting in a complex pattern with different topologies due to the symmetry-breaking effect of the applied field. This introduces spatially-varying Pancharatnam-Berry type geometric phase on to the paraxial beam of light, leading to the observation of SHEL in addition to the spin-to-vortex conversion. A wave-vector resolved conoscopic Mueller matrix measurement and analysis provides a first glimpse of the SHEL in the biaxial crystal, identified via the appearance of weak circular birefringence. The emergence of field-controllable fast-axis orientation of the crystal and the resulting SHEL provides a new degree of freedom for affecting and controlling the spin and orbital angular momentum of photons to unravel the rich underlying physics of optical crystals and aid in the development of active photonic spin-Hall devices.

Gold nanoparticles prepared by electro-exploding wire technique in aqueous solutions

Science.gov (United States)

Kumar, Lalit; Kapoor, Akanksha; Meghwal, Mayank; Annapoorni, S.

2016-05-01

This article presents an effective approach for the synthesis of Au nanoparticles via an environmentally benevolent electro-exploding wire (EEW) technique. In this process, Au nanoparticles evolve through the plasma generated from the parent Au metal. Compared to other typical chemical methods, electro-exploding wire technique is a simple and economical technique which normally operates in water or organic liquids under ambient conditions. Efficient size control was achieved using different aqueous medium like (1mM) NaCl, deionized water and aqueous solution of sodium hydroxide (NaOH, pH 9.5) using identical electro-exploding conditions. The gold nanoparticles exhibited the UV-vis absorption spectrum with a maximum absorption band at 530 nm, similar to that of gold nanoparticles chemically prepared in a solution. The mechanism of size variation of Au nanoparticles is also proposed. The results obtained help to develop methodologies for the control of EEW based nanoparticle growth and the functionalization of nanoparticle surfaces by specific interactions.

Direct electro-optic effect in langasites and α-quartz

Science.gov (United States)

Ivanov, Vadim

2018-05-01

Strain-constant (clamped) electro-optic coefficients r11S of langasite La3Ga5SiO14 (LGS), langatate La3Ga5.5Ta0.5O14 (LGT), catangasite Ca3TaGa3Si2O14 (CTGS) and α-quartz are measured at 1540 nm in the frequency range of 3-25 MHz. Experimental ratio of clamped and unclamped electro-optic coefficients r11S/r11T is 0.97 for LGS, 0.91 for LGT, 0.31 for CTGS, and 0.49 for quartz. Most of direct electro-optic effect in LGS and LGT is associated with lanthanum ions: clamped electro-optic coefficient r11S in lanthanum-free CTGS is 14 times less than in LGS. Low piezoelectric contribution to unclamped electro-optic coefficient r11T makes LGS and LGT promising materials for electro-optic devices, whose performance can be deteriorated by piezoelectric effect, especially, for high-voltage optical voltage sensors.

Electro-Fenton oxidation of reverse osmosis concentrate from sanitary landfill leachate: Evaluation of operational parameters.

Science.gov (United States)

Fernandes, Annabel; Labiadh, Lazhar; Ciríaco, Lurdes; Pacheco, Maria José; Gadri, Abdellatif; Ammar, Salah; Lopes, Ana

2017-10-01

The electro-Fenton oxidation of a concentrate from reverse osmosis of a sanitary landfill leachate, with an initial chemical oxygen demand (COD) of 42 g L -1 , was carried out using a carbon-felt cathode and a boron doped diamond anode. The influence of the applied current intensity, initial pH and dissolved iron initial concentration on the electro-Fenton process was assessed. For the experimental conditions used, results showed that the initial pH is the parameter that more strongly influences the current efficiency of the electro-Fenton process, being this influence more pronounced on the oxidation rate than on the mineralization rate of the organic matter. The increase in iron initial concentration was found to be detrimental, since the natural amount of iron present in the effluent, 73 mg L -1 of total iron and 61 mg L -1 of dissolved iron, was sufficient to ensure the electro-Fenton process at the applied intensities - 0.2-1.4 A. For the more favourable conditions studied, initial pH of 3 and natural iron concentration, it was found an increase in the organic load and nitrogen removals with the applied current intensity. For the highest current intensity applied, a COD removal of 16.7 g L -1 was achieved after 8-h experiments. Copyright © 2017 Elsevier Ltd. All rights reserved.

Spin physics: A new twist on heavy-ion experiments at RHIC

International Nuclear Information System (INIS)

Tannenbaum, M.J.

1998-01-01

Operation of RHIC with two beams of highly polarized protons (70%, either longitudinal or transverse) at high luminosity L = 2 · 10 32 cm -2 sec -1 for two months/year will allow high statistics studies of polarization phenomena in the perturbative region of hard scattering where both QCD and ElectroWeak theory make detailed predictions for polarization effects. The collision c.m. energy, √s = 50--500 GeV, represents a new domain for the study of spin. Direct photon production will be used to measure the gluon polarization in the polarized proton. A new twist comes from W-boson production which is expected to be 100% parity violating and will thus allow measurements of flavor separated quark and antiquark (u, anti u, d, anti d) polarization distributions. Searches for parity violation in strong interaction processes such as jet and leading particle production will be a sensitive way to look for new physics beyond the standard model, one possibility being quark substructure

Electro-Catalysis System for Biodiesel Synthesis from Palm Oil over Dielectric-Barrier Discharge Plasma Reactor

Directory of Open Access Journals (Sweden)

Istadi Istadi

2014-07-01

Full Text Available Biodiesel synthesis reaction routes from palm oil using plasma electro-catalysis process over Dielectric-Barrier Discharge (DBD plasma reactor were studied. The study was focused on finding possible reaction mechanism route during plasma electro-catalysis process. The prediction was performed based on the changes of Gas Chromatography Mass Spectrometer (GC-MS and Fourier Transform Infra Red (FT-IR analyses to the biodiesel products with respect to time length of plasma treatment. It was found that main reaction mechanism occurred in the plasma electro-catalysis system was non-thermal pyrolysis rather than transesterification. The main reactions within the plasma treatment were due to collision between high energetic electrons (supplied from high voltage power supply through high voltage electrode and the reaction mixtures. The high energetic electrons affected the electrons pair of covalent bonding to be excited or dissociated even ionized at higher energy. Therefore, this plasma electro-catalysis system was promising for biodiesel synthesis from vegetable oils due to only very short time reaction was needed, even no need a catalyst, no soap formation, and no glycerol by-product. This system could produce fatty acid methyl ester yield of 75.65% at 120 seconds and other possible chemicals, such as alkynes, alkanes, esters, carboxylic acid, and aldehydes. However, during the plasma process, the reaction mechanisms were still difficult to be controlled due the action of available high energetic electrons. The advanced studies on how to control the reaction mechanism selectively in the plasma electro-catalysis will be published elsewhere. © 2014 BCREC UNDIP. All rights reservedReceived: 23rd January 2014; Revised: 20th March 2014; Accepted: 23rd March 2014[How to Cite: Istadi, I., Yudhistira, A.D., Anggoro, D.D., Buchori, L. (2014. Electro-Catalysis System for Biodiesel Synthesis from Palm Oil over Dielectric-Barrier Discharge Plasma Reactor

Characterization of the behaviour of electro-galvanised steel sheets in terms of corrosion

International Nuclear Information System (INIS)

Finoly, Guylene

1992-01-01

This research thesis reports the development of a test method for the characterization of the behaviour of electro-galvanised steel sheets (i.e. zinc coated steel sheets as those used in the automotive industry) with respect to corrosion, and the definition of a classification of these materials with respect to their surface activity. After an overview of the different existing methods of determination of corrosion rate, the author reports the development of an experimental device adapted to the electrochemical study of electro-galvanised sheets, i.e. adapted to their low thickness (0,7 mm) and coating characteristics (10 μm thick). This device is then used in the case of solid zinc. The authors reports the study of the behaviour of sheets in a NaCl solution in order to meet industrial conditions used to activate the surface before the phosphate conversion process which aims at ensuring paint adherence. A test is proposed and validated by comparison with other electrochemical or chemical methods, and used to study the behaviour of electro-galvanised sheets submitted to a phosphate conversion coating process [fr

SCALE FACTOR DETERMINATION METHOD OF ELECTRO-OPTICAL MODULATOR IN FIBER-OPTIC GYROSCOPE

Directory of Open Access Journals (Sweden)

A. S. Aleynik

2016-05-01

Full Text Available Subject of Research. We propose a method for dynamic measurement of half-wave voltage of electro-optic modulator as part of a fiber optic gyroscope. Excluding the impact of the angular acceleration o​n measurement of the electro-optical coefficient is achieved through the use of homodyne demodulation method that allows a division of the Sagnac phase shift signal and an auxiliary signal for measuring the electro-optical coefficient in the frequency domain. Method. The method essence reduces to decomposition of step of digital serrodyne modulation in two parts with equal duration. The first part is used for quadrature modulation signals. The second part comprises samples of the auxiliary signal used to determine the value of the scale factor of the modulator. Modeling is done in standalone model, and as part of a general model of the gyroscope. The applicability of the proposed method is investigated as well as its qualitative and quantitative characteristics: absolute and relative accuracy of the electro-optic coefficient, the stability of the method to the effects of angular velocities and accelerations, method resistance to noise in actual devices. Main Results. The simulation has showed the ability to measure angular velocity changing under the influence of angular acceleration, acting on the device, and simultaneous measurement of electro-optical coefficient of the phase modulator without interference between these processes. Practical Relevance. Featured in the paper the ability to eliminate the influence of the angular acceleration on the measurement accuracy of the electro-optical coefficient of the phase modulator will allow implementing accurate measurement algorithms for fiber optic gyroscopes resistant to a significant acceleration in real devices.

Analyticity in a phenomenology of electro-weak structure of hadrons

International Nuclear Information System (INIS)

Dubnicka, S.; Dubnickova, A. Z.

2010-01-01

The utility of an application of the analyticity in a phenomenology of electro-weak structure of hadrons is demonstrated in a number of obtained new and experimentally verifiable results. With this aim first the problem of an inconsistency of the asymptotic behavior of vector-meson-dominance model with the asymptotic behavior of form factors of baryons and nuclei is solved generally and a general approach for determination of the lowest normal and anomalous singularities of form factors from the corresponding Feynman diagrams is reviewed. Then many useful applications by making use of the analytic properties of electro-weak form factors and amplitudes of various electromagnetic processes of hadrons are carried out. (Author)

Enhancement the conditioning of waste activated sludge through a sequence of freeze/thaw-electro-Fenton process

Directory of Open Access Journals (Sweden)

Shahheidar Narjes

2018-03-01

Full Text Available Sludge conditioning is an important stage in sludge management. In the present study, a sequence of freeze/thaw-electro-Fenton process was designed and specific resistance filtration (SRF was monitored during sludge conditioning as an important factor in sludge dewaterability. Furthermore, protein and polysaccharide concentrations were measured during the experiments. Results showed that the lowest SRF value contributed to −10°C in freezing process which showed a reducing trend by decreasing solution pH. In addition, results revealed that solution pH less than 3 caused a significant improvement in sludge dewatering; so the lowest SRF has been registered at pH = 2. By increasing current intensity from 0.5 to 1A, SRF values were reduced and then followed by an enhancement with increasing current intensity to 3.2 A. The lowest SRF value (6.1 × 104 m/kg was obtained at H2O2 = 30 mg/L which was the best conditions for sludge dewatering.

Field effect control of electro-osmotic flow in microfluidic networks

NARCIS (Netherlands)

van der Wouden, E.J.

2006-01-01

This thesis describes the development of a Field Effect Flow Control (FEFC) system for the control of Electro Osmotic Flow (EOF) in microfluidic networks. For this several aspects of FEFC have been reviewed and a process to fabricate microfluidic channels with integrated electrodes has been

Spin-to-orbital momentum conversion via electro-optic Pockels effect in crystals

International Nuclear Information System (INIS)

Skab, Ihor; Vasylkiv, Yurij; Smaga, Ihor; Vlokh, Rostyslav

2011-01-01

In the present work we have demonstrated a possibility for operation by orbital angular momentum (OAM) of optical beams via the Pockels effect in solid-crystalline materials. Based on the analysis of an optical Fresnel ellipsoid perturbed by a conically shaped electric field, we have shown that the point groups of crystals convenient for the conversion of spin angular momentum (SAM) to OAM should contain a threefold symmetry axis or a sixfold inversion axis. The results of our experimental studies and theoretical simulations of the SAM-to-OAM conversion efficiency carried out for LiNbO 3 crystals agree well with each other.

Anisotropic interactions of a single spin and dark-spin spectroscopy in diamond

Science.gov (United States)

Epstein, R. J.; Mendoza, F. M.; Kato, Y. K.; Awschalom, D. D.

2005-11-01

Experiments on single nitrogen-vacancy (N-V) centres in diamond, which include electron spin resonance, Rabi oscillations, single-shot spin readout and two-qubit operations with a nearby13C nuclear spin, show the potential of this spin system for solid-state quantum information processing. Moreover, N-V centre ensembles can have spin-coherence times exceeding 50 μs at room temperature. We have developed an angle-resolved magneto-photoluminescence microscope apparatus to investigate the anisotropic electron-spin interactions of single N-V centres at room temperature. We observe negative peaks in the photoluminescence as a function of both magnetic-field magnitude and angle that are explained by coherent spin precession and anisotropic relaxation at spin-level anti-crossings. In addition, precise field alignment unmasks the resonant coupling to neighbouring `dark' nitrogen spins, otherwise undetected by photoluminescence. These results demonstrate the capability of our spectroscopic technique for measuring small numbers of dark spins by means of a single bright spin under ambient conditions.

Electro-oxidation of reverse osmosis concentrates generated in tertiary water treatment.

Science.gov (United States)

Pérez, G; Fernández-Alba, A R; Urtiaga, A M; Ortiz, I

2010-05-01

This work investigates the application of the electro-oxidation technology provided with boron doped diamond (BDD), an electrode material which has shown outstanding properties in oxidation of organic and inorganic compounds, for the treatment of reverse osmosis (RO) concentrates generated in tertiary wastewater treatment plants (WWTP). Chemical oxygen demand (COD), ammonium and several anions were measured during the electro-oxidation process, and the influence of the applied current density (20-200A/m(2)) was analysed on process kinetics. Analytical assessment showed that several emerging pollutants (pharmaceuticals, personal care products, stimulants, etc.) were presented both in the effluent of the secondary WWTP as well as in the RO concentrate. For this reason, a group of 10 emerging pollutants, those found with higher concentrations, was selected in order to test whether electro-oxidation can be also applied for their mitigation. In the removal of emerging pollutants the electrical current density in the range 20-100A/m(2) did not show influence likely due to the mass transfer resistance developed in the process when the oxidized solutes are present in such low concentrations. Their removal rates were fitted to first order expressions, and the apparent kinetic constants for the anodic oxidation of each compound were calculated. Finally, the formation of trihalomethanes (THMs) has been checked; concluding that after selecting the appropriate operational conditions the attained concentration is lower than the standards for drinking water established in European and EPA regulations. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Spin-photon interface and spin-controlled photon switching in a nanobeam waveguide

DEFF Research Database (Denmark)

Javadi, Alisa; Ding, Dapeng; Appel, Martin Hayhurst

2018-01-01

Access to the electron spin is at the heart of many protocols for integrated and distributed quantum-information processing [1-4]. For instance, interfacing the spin-state of an electron and a photon can be utilized to perform quantum gates between photons [2,5] or to entangle remote spin states [6......-9]. Ultimately, a quantum network of entangled spins constitutes a new paradigm in quantum optics [1]. Towards this goal, an integrated spin-photon interface would be a major leap forward. Here we demonstrate an efficient and optically programmable interface between the spin of an electron in a quantum dot...... and photons in a nanophotonic waveguide. The spin can be deterministically prepared with a fidelity of 96\\%. Subsequently the system is used to implement a "single-spin photonic switch", where the spin state of the electron directs the flow of photons through the waveguide. The spin-photon interface may...

Electro-optical Detection of Charged Particles

International Nuclear Information System (INIS)

Lazarus, D.M.

2001-01-01

The electric field of charged particles can induce transient changes in the polarization of light that produce sub-picosecond modulation of a laser beam. This is a consequence of the electro-optical effect in which the presence of the electric field in an electro-optical medium produces a change in the index of refraction of the medium resulting in a phase retardation between polarization components parallel and perpendicular to the electric field. We have observed the electro-optical effect due to 10 picosecond electron beam bunches with rise times that were limited by the bandwidth of our data acquisition system. This technology is being applied to particle beam diagnostics and has the potential to produce charged particle detectors combining excellent spatial resolution with unprecedented temporal precision.

Nuclear spins in nanostructures

International Nuclear Information System (INIS)

Coish, W.A.; Baugh, J.

2009-01-01

We review recent theoretical and experimental advances toward understanding the effects of nuclear spins in confined nanostructures. These systems, which include quantum dots, defect centers, and molecular magnets, are particularly interesting for their importance in quantum information processing devices, which aim to coherently manipulate single electron spins with high precision. On one hand, interactions between confined electron spins and a nuclear-spin environment provide a decoherence source for the electron, and on the other, a strong effective magnetic field that can be used to execute local coherent rotations. A great deal of effort has been directed toward understanding the details of the relevant decoherence processes and to find new methods to manipulate the coupled electron-nuclear system. A sequence of spectacular new results have provided understanding of spin-bath decoherence, nuclear spin diffusion, and preparation of the nuclear state through dynamic polarization and more general manipulation of the nuclear-spin density matrix through ''state narrowing.'' These results demonstrate the richness of this physical system and promise many new mysteries for the future. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

Single spin asymmetries and the spin of the proton

International Nuclear Information System (INIS)

Dominguez Z, G.; Herrera C, G.

2000-01-01

We study the spin asymmetries of inclusive π + , π 0 , π - , η and γ production in the interaction of a polarized with a non polarized proton, in the frame of a two component model. Particle production in the model is assumed to consist of a conventional QCD fragmentation process plus a recombination mechanism. The presence of Thomas precession in the recombination process seems to be responsible for the production spin asymmetry. (Author) 12 refs., 8 figs

Thermo-electro-chemical storage (TECS) of solar energy

International Nuclear Information System (INIS)

Wenger, Erez; Epstein, Michael; Kribus, Abraham

2017-01-01

Highlights: • A solar plant with thermally regenerative battery unifies energy conversion and storage. • Storage is a flow battery with thermo-chemical charging and electro-chemical discharging. • Sodium-sulfur and zinc-air systems are investigated as candidate storage materials. • Theoretical solar to electricity efficiencies of over 60% are predicted. • Charging temperature can be lowered with hybrid carbothermic reduction. - Abstract: A new approach for solar electricity generation and storage is proposed, based on the concept of thermally regenerative batteries. Concentrated sunlight is used for external thermo-chemical charging of a flow battery, and electricity is produced by conventional electro-chemical discharge of the battery. The battery replaces the steam turbine, currently used in commercial concentrated solar power (CSP) plants, potentially leading to much higher conversion efficiency. This approach offers potential performance, cost and operational advantages compared to existing solar technologies, and to existing storage solutions for management of an electrical grid with a significant contribution of intermittent solar electricity generation. Here we analyze the theoretical conversion efficiency for new thermo-electro-chemical storage (TECS) plant schemes based on the electro-chemical systems of sodium-sulfur (Na-S) and zinc-air. The thermodynamic upper limit of solar to electricity conversion efficiency for an ideal TECS cycle is about 60% for Na-S at reactor temperature of 1550 K, and 65% for the zinc-air system at 1750 K, both under sunlight concentration of 3000. A hybrid process with carbothermic reduction in the zinc-air system reaches 60% theoretical efficiency at the more practical conditions of reaction temperature <1200 K and concentration <1000. Practical TECS plant efficiency, estimated from these upper limits, may then be much higher compared to existing solar electricity technologies. The technical and economical

Crosslinked polyimide electro-optic materials

Energy Technology Data Exchange (ETDEWEB)

Kowalczyk, T.C.; Kosc, T.Z.; Singer, K.D. [Case Western Reserve University, Department of Physics, Cleveland, Ohio 44106-7079 (United States); Beuhler, A.J.; Wargowski, D.A. [Amoco Research Center, Amoco Chemical Co., Naperville, Illinois 60566 (United States); Cahill, P.A.; Seager, C.H.; Meinhardt, M.B. [Sandia National Laboratories, Division 1811, Albuquerque, New Mexico 87185-1407 (United States); Ermer, S. [Lockheed Research and Development Division, Palo Alto, California 94304 (United States)

1995-11-15

We report studies of the optical and electro-optic properties of guest--host polymeric nonlinear optical materials based on aromatic, fluorinated, fully imidized, organic soluble, thermally, and photochemically crosslinkable, guest--host polyimides. We have introduced temperature stable nonlinear optical chromophores into these polyimides and studied optical losses, electric field poling, electro-optic properties, and orientational stability. We measured electro-optic coefficients of 5.5 and 12.0 pm/V for ((2,6-Bis(2-(3-(9-(ethyl)carbazolyl))ethenyl)4H-pyran-4-ylidene)propanedinitrile) (4-(Dicyanomethylene)-2-methyl-6-(p -dimethylaminostyryl)-4H-pyran) DCM-doped guest--host systems at 800 nm using a poling field of 1.3 MV/cm. Poling induced nonlinearities in single-layer films were in agreement with the oriented gas model, but were lower in three-layer films due to voltage division across the layers. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Environmental Effects on Quantum Reversal of Mesoscopic Spins

Science.gov (United States)

Giraud, R.; Chiorescu, I.; Wernsdorfer, W.; Barbara, B.; Jansen, A. G. M.; Caneschi, A.; Mueller, A.; Tkachuk, A. M.

2002-10-01

extension of these studies beyond molecular magnetism. Single-ion slow quantum relaxation is observed in rare-earth Ho3+ ions highly diluted in an insulating matrix LiYF4. This relaxation is due to the coherent tunneling of individual Ho3+ spins strongly coupled to their nuclear spins, leading to electro-nuclear entangled states at avoided level crossings. In fact tunneling of the spin system is induced by the hyperfine coupling. Together with the important role of the "spin bath", the roles of cross-spin and spin-phonon relaxations are also considered. All these results confirm the emergence of a new field of research: "mesoscopic magnetism".

Electro-optic methods for longitudinal bunch diagnostics at FLASH

International Nuclear Information System (INIS)

Steffen, B.R.

2007-07-01

Precise measurements of the temporal profile of sub-picosecond electron bunches are of high interest for the optimization and operation of VUV and X-ray free electron lasers. In this thesis, the shortest electro-optic signals measured so far for electron bunch diagnostics are presented, reaching a time resolution of better than 50 fs (rms). The e ects that introduce signal distortions and limit the time resolution are studied in numerical simulations for different electro-optic detection materials and techniques. The time resolution is mainly limited by lattice resonances of the electro-optic crystal. Electro-optic signals as short as 54 fs (rms) are obtained with gallium phosphide (GaP) crystals in a crossed polarizer detection scheme using temporally resolved electro-optic detection. Measuring near crossed polarization, where the electro-optic signal is proportional to the velocity field of the relativistic electron bunch, the shortest obtained signal width is 70 fs (rms). The electro-optic signals are compared to electron bunch shapes that are measured simultaneously with a transverse deflecting structure with 20 fs resolution. Numerical simulations using the bunch shapes as determined with the transverse deflecting cavity as input data are in excellent agreement with electro-optical signals obtained with GaP, both for temporally and spectrally resolved measurements. In the case of zinc telluride (ZnTe) the observed signals are slightly broader and significantly smaller than expected from simulations. These discrepancies are probably due to the poor optical quality of the available ZnTe crystals. (orig.)

Electro-optic methods for longitudinal bunch diagnostics at FLASH

Energy Technology Data Exchange (ETDEWEB)

Steffen, B.R.

2007-07-15

Precise measurements of the temporal profile of sub-picosecond electron bunches are of high interest for the optimization and operation of VUV and X-ray free electron lasers. In this thesis, the shortest electro-optic signals measured so far for electron bunch diagnostics are presented, reaching a time resolution of better than 50 fs (rms). The e ects that introduce signal distortions and limit the time resolution are studied in numerical simulations for different electro-optic detection materials and techniques. The time resolution is mainly limited by lattice resonances of the electro-optic crystal. Electro-optic signals as short as 54 fs (rms) are obtained with gallium phosphide (GaP) crystals in a crossed polarizer detection scheme using temporally resolved electro-optic detection. Measuring near crossed polarization, where the electro-optic signal is proportional to the velocity field of the relativistic electron bunch, the shortest obtained signal width is 70 fs (rms). The electro-optic signals are compared to electron bunch shapes that are measured simultaneously with a transverse deflecting structure with 20 fs resolution. Numerical simulations using the bunch shapes as determined with the transverse deflecting cavity as input data are in excellent agreement with electro-optical signals obtained with GaP, both for temporally and spectrally resolved measurements. In the case of zinc telluride (ZnTe) the observed signals are slightly broader and significantly smaller than expected from simulations. These discrepancies are probably due to the poor optical quality of the available ZnTe crystals. (orig.)

Electro-Fenton decolourisation of dyes in an airlift continuous reactor using iron alginate beads.

Science.gov (United States)

Iglesias, O; Rosales, E; Pazos, M; Sanromán, M A

2013-04-01

In this study, electro-Fenton dye degradation was performed in an airlift continuous reactor configuration by harnessing the catalytic activity of Fe alginate gel beads. Electro-Fenton experiments were carried out in an airlift reactor with a working volume of 1.5 L, air flow of 1.5 L/min and 115 g of Fe alginate gel beads. An electric field was applied by two graphite bars connected to a direct current power supply with a constant potential drop. In this study, Lissamine Green B and Reactive Black 5 were selected as model dyes. Fe alginate gel beads can be used as an effective heterogeneous catalyst for the degradation of organic dyes in the electro-Fenton process, as they are more efficient than the conventional electrochemical techniques. At optimal working conditions (3 V and pH 2), the continuous process was performed. For both dyes, the degree of decolourisation increases when the residence time augments. Taking into account hydrodynamic and kinetic behaviour, a model to describe the reactor profile was obtained, and the standard deviation between experimental and theoretical data was lower than 6%. The results indicate the suitability of the electro-Fenton technique to oxidise polluted effluents in the presence of Fe alginate gel beads. Moreover, the operation is possible in a continuous airlift reactor, due to the entrapment of iron in the alginate matrix.

Study of the p(e,e'π+)n electro-production reaction: form factor and electromagnetic radius of pion

International Nuclear Information System (INIS)

Michel, Bernard

1977-01-01

After having recalled the definitions and theoretical knowledge on the form factor and electromagnetic radius of hadron and pion, and discussed the relationship between electro-production and form factor for the pion, this research thesis recalls some theoretical aspects of the electro-production process. The author discusses the reaction kinematics and shows how the electro-production cross section can be broken down in terms of photon polarization. Then, he focuses on the cross section dynamic structure. After having recalled the different possible choices for amplitudes, he studies their behaviour, firstly within the framework of the Born approximation, and then within the framework of commonly used models, notably to take the resonant part of the phenomenon into account. The limits of the different models are outlined. The second part addresses the study of forward electro-production. The author shows how the pion form factor can be simply optimized. The author describes the experimental arrangement: electron beam and liquid hydrogen target, detection system, normalisation device, data acquisition logics. In the next chapter, the author describes how data are recorded until the obtainment of N electro-production events. Results are then interpreted in terms of form factor and electromagnetic radius. They are also compared with published results obtained with other electro-production experiments or measurements based on other processes [fr

Removal of PAHs from contaminated clayey soil by means of electro-osmosis

KAUST Repository

Lima, Ana T.

2011-06-01

The removal of polycyclic aromatic hydrocarbons (PAHs) from clayey soils is an intricate task. The low porosity of compacted clayey soil hinders bacterial activity and makes convective removal by hydraulic flow impossible. Electro-osmosis is a process that has been used for the mobilization and cleanup of contaminants in clayey soils with varying successes. The present study focuses on the remediation of a contaminated peaty clay soil, located in Olst - the Netherlands, by means of electro-osmosis. The soil was originally contaminated by an asphalt production plant, active from 1903 to 1983, and presents high levels of all 16 priority PAHs indicated by the US Environmental Protection Agency (EPA). Such a long contact times of PAH with the soil (≥100 years) presents a unique study material with well established solid/liquid contaminant partitioning equilibrium, preferable to artificially spiked soil. A batch of 6 electro-osmosis laboratory experiments was carried out to study the removal of 16 PAHs through electro-osmosis. In these experiments, water and a surfactant (Tween 80) were used to enhance the PAH desorption. The electro-osmotic conductivities ranged from 2.88 × 10-10 to a substantial 1.19 × 10-7 m2 V-1 s -1 when applying a current density of 0.005-0.127 A m-2. Electro-osmosis was expected to occur towards the cathode, because of natural soil characteristics (negative zeta potential), but presented scattered directions. The use of reference electrodes proved to be very effective to the prediction of the flow direction. Finally, the addition of Tween 80 as a surfactant enhanced PAH removal up to 30% of the total PAH content of the soil in 9 days. © 2011 Elsevier B.V.

Spin-to-orbital momentum conversion via electro-optic Pockels effect in crystals

Energy Technology Data Exchange (ETDEWEB)

Skab, Ihor; Vasylkiv, Yurij; Smaga, Ihor; Vlokh, Rostyslav [Institute of Physical Optics, 23 Dragomanov Street, 79005 Lviv (Ukraine)

2011-10-15

In the present work we have demonstrated a possibility for operation by orbital angular momentum (OAM) of optical beams via the Pockels effect in solid-crystalline materials. Based on the analysis of an optical Fresnel ellipsoid perturbed by a conically shaped electric field, we have shown that the point groups of crystals convenient for the conversion of spin angular momentum (SAM) to OAM should contain a threefold symmetry axis or a sixfold inversion axis. The results of our experimental studies and theoretical simulations of the SAM-to-OAM conversion efficiency carried out for LiNbO{sub 3} crystals agree well with each other.

Spin physics at RHIC a new twist on the heavy ion experiments

International Nuclear Information System (INIS)

Tannenbaum, M.J.

1996-01-01

Operation of RHIC with two beams of highly polarized protons (70%, either longitudinal or transverse) at high luminosity ???? = 2 circ 10 32 cm -2 sec -1 for two months/year will allow high statistics studies of polarization phenomena in the perturbative region of hard scattering where both QCD and ElectroWeak theory make detailed predictions for polarization effects. The collision c.m energy, √s = 200 - 500 GeV, represents a new domain for the study of spin. Direct photon production win be used to measure the gluon polarization in the polarized proton. A new twist comes from W-boson production which is expected to be 100% parity violating and will thus allow measurements of flavor separated quark and antiquark (u, u, d, d) polarization distributions. Searches for parity violation in strong interaction processes such as jet and leading particle production will be a sensitive way to look for new physics beyond the standard model, one possibility being quark substructure

Highly efficient polymer solar cells with printed photoactive layer: rational process transfer from spin-coating

KAUST Repository

Zhao, Kui

2016-09-05

Scalable and continuous roll-to-roll manufacturing is at the heart of the promise of low-cost and high throughput manufacturing of solution-processed photovoltaics. Yet, to date the vast majority of champion organic solar cells reported in the literature rely on spin-coating of the photoactive bulk heterojunction (BHJ) layer, with the performance of printed solar cells lagging behind in most instances. Here, we investigate the performance gap between polymer solar cells prepared by spin-coating and blade-coating the BHJ layer for the important class of modern polymers exhibiting no long range crystalline order. We find that thickness parity does not always yield performance parity even when using identical formulations. Significant differences in the drying kinetics between the processes are found to be responsible for BHJ nanomorphology differences. We propose an approach which benchmarks the film drying kinetics and associated BHJ nanomorphology development against those of the champion laboratory devices prepared by spin-coating the BHJ layer by adjusting the process temperature. If the optimization requires the solution concentration to be changed, then it is crucial to maintain the additive-to-solute volume ratio. Emulating the drying kinetics of spin-coating is also shown to help achieve morphological and performance parities. We put this approach to the test and demonstrate printed PTB7:PC71BM polymer solar cells with efficiency of 9% and 6.5% PCEs on glass and flexible PET substrates, respectively. We further demonstrate performance parity for two other popular donor polymer systems exhibiting rigid backbones and absence of a long range crystalline order, achieving a PCE of 9.7%, the highest efficiency reported to date for a blade coated organic solar cell. The rational process transfer illustrated in this study should help the broader and successful adoption of scalable printing methods for these material systems.

Spin inelastic electron tunneling spectroscopy on local spin adsorbed on surface.

Science.gov (United States)

Fransson, J

2009-06-01

The recent experimental conductance measurements taken on magnetic impurities on metallic surfaces, using scanning tunneling microscopy technique and suggesting occurrence of inelastic scattering processes, are theoretically addressed. We argue that the observed conductance signatures are caused by transitions between the spin states that have opened due to, for example, exchange coupling between the local spins and the tunneling electrons, and are directly interpretable in terms of inelastic transitions energies. Feasible measurements using spin-polarized scanning tunneling microscopy that would enable new information about the excitation spectrum of the local spins are discussed.

Experimental electro-thermal method for nondestructively testing welds in stainless steel pipes

International Nuclear Information System (INIS)

Green, D.R.

1979-01-01

Welds in austenitic stainless steel pipes are notoriously difficult to nondestructively examine using conventional ultrasonic and eddy current methods. Survace irregularities and microscopic variations in magnetic permeability cause false eddy current signal variations. Ultrasonic methods have been developed which use computer processing of the data to overcome some of the problems. Electro-thermal nondestructive testing shows promise for detecting flaws that are difficult to detect using other NDT methods. Results of a project completed to develop and demonstrate the potential of an electro-thermal method for nondestructively testing stainless steel pipe welds are presented. Electro-thermal NDT uses a brief pulse of electrical current injected into the pipe. Defects at any depth within the weld cause small differences in surface electrical current distribution. These cause short-lived transient temperature differences on the pipe's surface that are mapped using an infrared scanning camera. Localized microstructural differences and normal surface roughness in the welds have little effect on the surface temperatures

Decolorisation of wastewater with a high percentage of indigo by the electro-coagulation method

International Nuclear Information System (INIS)

Mejia, Claudia; Osorio Victor

2003-01-01

The electrochemical technology has enlarged its participation in the industry and it has been developed quickly like a strong and competitive alternative in an important number of processes; in the last years, one that is developing with force is the treatment of industrial effluents. In many cases, these methods are advantageous for their low or null consumption of reagents, what makes them environmentally attractiveness; this treatment technique uses as matter a clean reagent it prevails: the electric power. The fading is generally obtained by electro-oxidation with non-soluble anodes or for electro-coagulation with soluble anodes in those that the hydroxides of the metal resultants adsorbent the coloring. The purpose of this work is discoloring the residual waters of an industrial laundry by means of electro-coagulation

Electro-volatilization of ruthenium in nitric medium: influences of ruthenium species nature and models solutions composition; Electro-volatilisation du ruthenium en milieu nitrique: influence de la nature des formes chimiques du ruthenium et de la composition des solutions modeles de dissolution

Energy Technology Data Exchange (ETDEWEB)

Mousset, F

2004-12-15

Ruthenium is one of the fission products in the reprocessing of irradiated fuels that requires a specific processing management. Its elimination, upstream by the PUREX process, has been considered. A process, called electro-volatilization, which take advantage of the RuO{sub 4} volatility, has been optimised in the present study. It consists in a continuous electrolysis of ruthenium solutions in order to generate RuO{sub 4} species that is volatilized and easily trapped. This process goes to satisfying ruthenium elimination yields with RuNO(NO{sub 3}){sub 3}(H{sub 2}O){sub 2} synthetic solutions but not with fuel dissolution solutions. Consequently, this work consisted in the speciation studies of dissolved ruthenium species were carried out by simulating fuel solutions produced by hot acid attack of several ruthenium compounds (Ru(0), RuO{sub 2},xH{sub 2}O, polymetallic alloy). In parallel with dissolution kinetic studies, the determination of dissolved species was performed using voltammetry, spectrometry and spectro-electrochemistry. The results showed the co-existence of Ru(IV) and RuNO(NO{sub 2}){sub 2}(H{sub 2}O){sub 3}. Although these species are different from synthetic RuNO(NO{sub 3}){sub 3}(H{sub 2}O){sub 2}, their electro-oxidation behaviour are similar. The electro-volatilization tests of these dissolution solutions yielded to comparable results as the synthetic RuNO(NO{sub 3}){sub 3}(H{sub 2}O){sub 2} solutions. Then, complexity increase of models solutions was performed by in-situ generation of nitrous acid during ruthenium dissolution. Nitrous acid showed a catalytic effect on ruthenium dissolution. Its presence goes to quasi exclusively RuNO(NO{sub 2}){sub 2}(H{sub 2}O){sub 3} species. It is also responsible of the strong n-bond formation between Ru{sup 2+} and NO{sup +}. In addition, it has been shown that its reducing action on RuO{sub 4} hinders the electro-volatilization process. Mn{sup 2+} and Ce{sup 3+} cations also reveal, but to a lesser

A Comparative Analysis of 2-(Thiocyanomethylthio-Benzothiazole Degradation Using Electro-Fenton and Anodic Oxidation on a Boron-Doped Diamond Electrode

Directory of Open Access Journals (Sweden)

Armando Vázquez

2018-01-01

Full Text Available 2-(Thiocyanomethylthio-benzothiazole (TCMTB is used as fungicide in the paper, tannery, paint, and coatings industries, and its study is important as it is considered toxic to aquatic life. In this study, a comparison of direct anodic oxidation (AO using a boron-doped diamond electrode (BDD and electro-Fenton (EF processes for TCMTB degradation in acidic chloride and sulfate media using a FM01-LC reactor was performed. The results of the electrolysis processes studied in the FM01-LC reactor showed a higher degradation of TCMTB with the anodic oxidation process than with the electro-Fenton process, reaching 81% degradation for the former process versus 47% degradation for the latter process. This difference was attributed to the decrease in H2O2 during the EF process, due to parallel oxidation of chlorides. The degradation rate and current efficiency increased as a function of volumetric flow rate, indicating that convection promotes anodic oxidation and electro-Fenton processes. The results showed that both AO and EF processes could be useful strategies for TCMTB toxicity reduction in wastewaters.

Electro-active bio-films: formation, characterization and mechanisms

International Nuclear Information System (INIS)

Parot, Sandrine

2007-01-01

Some bacteria, which are able to exchange electrons with a conductive material without mediator form on conductive surfaces electro-active bio-films. This bacterial property has been recently discovered (2001). Objectives of this work are to develop electro-active bio-films in various natural environments from indigenous flora, then through complementary electrochemical techniques (chrono-amperometry and cyclic voltammetry), to evaluate electro-activity of isolates coming from so-formed bio-films and to characterize mechanisms of electron transfer between bacteria and materials. First, electro-active bio-films have been developed under chrono-amperometry in garden compost and in water coming from Guyana mangrove. These bio-films were respectively able to use an electrode as electron acceptor (oxidation) or as electron donor (reduction). In compost, results obtained in chrono-amperometry and cyclic voltammetry suggest a two-step electron transfer: slow substrate consumption, then rapid electron transfer between bacteria and the electrode. Thereafter, the ability to reduce oxygen was demonstrated with cyclic voltammetry for facultative aerobic isolates from compost bio-films (Enterobacter spp. and Pseudomonas spp.) and for aerobic isolates obtained from marine electro-active bio-films (Roseobacter spp. in majority). Finally, bio-films inducing current increase in chrono-amperometry were developed in bioreactor with synthetic medium from a pure culture of isolates. Hence, for the first time, electro-activity of several anaerobic strains of Geobacter bremensis isolated from compost bio-films was highlighted. (author) [fr

Concrete decontamination by electro-hydraulic scabbling (EHS). Final report

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-10-01

Contamination of concrete structures by radionuclides, hazardous metals and organic substances (including PCB`s) occurs at many DOE sites. The contamination of concrete structures (walls, floors, ceilings, etc.) varies in type, concentration, and especially depth of penetration into the concrete. In many instances, only the surface layer of concrete is contaminated, up to a depth of one inch, according to estimates provided in the R and D ID document. Then, removal of the concrete surface layer (scabbling) is considered to be the most effective decontamination method. Textron Systems Corp. (TSC) has developed a scabbling concept based on electro-mechanical phenomena accompanying strong electric pulses generated by applying high voltage at the concrete/water interface. Depending on the conditions, the electric discharge may occur either through a waste layer or through the concrete body itself. This report describes the development, testing, and results of this electro-mechanical process. Phase 1 demonstrated the feasibility of the process for the controlled removal of a thin layer of contaminated concrete. Phase 2 designed, fabricated, and tested an integrated subscale unit. This was tested at Fernald. In Phase 3, the scabbling unit was reconfigured to increase its power and processing rate. Technology transfer to an engineering contracting company is continuing.

Concrete decontamination by electro-hydraulic scabbling (EHS). Final report

International Nuclear Information System (INIS)

1997-10-01

Contamination of concrete structures by radionuclides, hazardous metals and organic substances (including PCB's) occurs at many DOE sites. The contamination of concrete structures (walls, floors, ceilings, etc.) varies in type, concentration, and especially depth of penetration into the concrete. In many instances, only the surface layer of concrete is contaminated, up to a depth of one inch, according to estimates provided in the R and D ID document. Then, removal of the concrete surface layer (scabbling) is considered to be the most effective decontamination method. Textron Systems Corp. (TSC) has developed a scabbling concept based on electro-mechanical phenomena accompanying strong electric pulses generated by applying high voltage at the concrete/water interface. Depending on the conditions, the electric discharge may occur either through a waste layer or through the concrete body itself. This report describes the development, testing, and results of this electro-mechanical process. Phase 1 demonstrated the feasibility of the process for the controlled removal of a thin layer of contaminated concrete. Phase 2 designed, fabricated, and tested an integrated subscale unit. This was tested at Fernald. In Phase 3, the scabbling unit was reconfigured to increase its power and processing rate. Technology transfer to an engineering contracting company is continuing

Control of the Speed of a Light-Induced Spin Transition through Mesoscale Core-Shell Architecture.

Science.gov (United States)

Felts, Ashley C; Slimani, Ahmed; Cain, John M; Andrus, Matthew J; Ahir, Akhil R; Abboud, Khalil A; Meisel, Mark W; Boukheddaden, Kamel; Talham, Daniel R

2018-05-02

The rate of the light-induced spin transition in a coordination polymer network solid dramatically increases when included as the core in mesoscale core-shell particles. A series of photomagnetic coordination polymer core-shell heterostructures, based on the light-switchable Rb a Co b [Fe(CN) 6 ] c · mH 2 O (RbCoFe-PBA) as core with the isostructural K j Ni k [Cr(CN) 6 ] l · nH 2 O (KNiCr-PBA) as shell, are studied using temperature-dependent powder X-ray diffraction and SQUID magnetometry. The core RbCoFe-PBA exhibits a charge transfer-induced spin transition (CTIST), which can be thermally and optically induced. When coupled to the shell, the rate of the optically induced transition from low spin to high spin increases. Isothermal relaxation from the optically induced high spin state of the core back to the low spin state and activation energies associated with the transition between these states were measured. The presence of a shell decreases the activation energy, which is associated with the elastic properties of the core. Numerical simulations using an electro-elastic model for the spin transition in core-shell particles supports the findings, demonstrating how coupling of the core to the shell changes the elastic properties of the system. The ability to tune the rate of optically induced magnetic and structural phase transitions through control of mesoscale architecture presents a new approach to the development of photoswitchable materials with tailored properties.

Alternative electro-chemically based processing routes for joining of plasma facing components

Energy Technology Data Exchange (ETDEWEB)

Krauss, Wolfgang, E-mail: wolfgang.krauss@kit.edu [Karlsruhe Institute of Technology (KIT), Institute for Materials Research III, Hermann-von-Helmholtz-Platz 1 76344 Eggenstein-Leopoldshafen (Germany); Lorenz, Julia; Holstein, Nils; Konys, Juergen [Karlsruhe Institute of Technology (KIT), Institute for Materials Research III, Hermann-von-Helmholtz-Platz 1 76344 Eggenstein-Leopoldshafen (Germany)

2011-10-15

Tungsten is considered in fusion technology as functional and structural material in the area of blanket and divertor for future application in DEMO. The KIT design of a He-cooled divertor includes joints between W and W-alloys as well as of W with Eurofer-steel. The main challenges range from expansion mismatch problem for tungsten/steel joints over metallurgical reactions with brittle phase formation to crack stopping ability and excellent surface wetting. These requirements were only met partly and insufficiently in the past e.g. by direct Cu-casting of tungsten onto steel. Both, the joining needs and the observed failure scenarios of conventionally joined components initiated the development of improved joining technologies based on electro-chemical processing routes. As electrolytes aqueous and aprotic, water free, system are integrated into this development line. In the first step principle requirements are presented to guarantee a reproducible and adherent deposition of scales based on Ni and Cu acting as inter layers and filler, respectively, to generate a real metallurgical bonding as demonstrate by 1100 deg. C joining tests. The development field aprotic systems based on ionic liquids is discussed with respect to enable development of refractory metal based fillers with focus high temperature W-W brazing.

Newly designed PdRuBi/N-Graphene catalysts with synergistic effects for enhanced ethylene glycol electro-oxidation

International Nuclear Information System (INIS)

Li, Tengfei; Huang, Yiyin; Ding, Kui; Wu, Peng; Abbas, Syed Comail; Ghausi, Muhammad Arsalan; Zhang, Teng; Wang, Yaobing

2016-01-01

Graphical abstract: We rationally design and synthesize a ternary PdRuBi/NG catalyst with significantly enhanced catalytic activity with synergetic effect of Ru and Bi towards ethylene glycol electro-oxidation. - Abstract: Palladium (Pd)-based catalysts are appealing electro-catalysts for alcohol oxidation reaction in fuel cell, but still not efficient as the complicated oxidation process and sluggish kinetic. Here we rationally design and synthesize a PdRuBi/NG tri-metallic catalyst with space synergetic effect for enhanced ethylene glycol electro-oxidation, in which both Ru and Bi in the catalyst are synergistic effective in promoting catalytic activity of Pd catalytic interlayer by electronic effect and surface modification mechanism respectively. It shows 4.2 times higher peak current density towards ethylene glycol electro-oxidation than commercial Pd/C catalyst, and the catalytic durability is also greatly improved.

Bipolar spintronics: from spin injection to spin-controlled logic

International Nuclear Information System (INIS)

Zutic, Igor; Fabian, Jaroslav; Erwin, Steven C

2007-01-01

An impressive success of spintronic applications has been typically realized in metal-based structures which utilize magnetoresistive effects for substantial improvements in the performance of computer hard drives and magnetic random access memories. Correspondingly, the theoretical understanding of spin-polarized transport is usually limited to a metallic regime in a linear response, which, while providing a good description for data storage and magnetic memory devices, is not sufficient for signal processing and digital logic. In contrast, much less is known about possible applications of semiconductor-based spintronics and spin-polarized transport in related structures which could utilize strong intrinsic nonlinearities in current-voltage characteristics to implement spin-based logic. Here we discuss the challenges for realizing a particular class of structures in semiconductor spintronics: our proposal for bipolar spintronic devices in which carriers of both polarities (electrons and holes) contribute to spin-charge coupling. We formulate the theoretical framework for bipolar spin-polarized transport, and describe several novel effects in two- and three-terminal structures which arise from the interplay between nonequilibrium spin and equilibrium magnetization

Electro-chemical grinding

Science.gov (United States)

Feagans, P. L.

1972-01-01

Electro-chemical grinding technique has rotation speed control, constant feed rates, and contour control. Hypersonic engine parts of nickel alloys can be almost 100% machined, keeping tool pressure at virtual zero. Technique eliminates galling and permits constant surface finish and burr-free interrupted cutting.

Influence of cathode on the electro-generation of peroxydisulfuric acid oxidant and its application for effective removal of SO_2 by room temperature electro-scrubbing process

International Nuclear Information System (INIS)

Balaji, Subramanian; Muthuraman, Govindan; Moon, Il Shik

2015-01-01

Highlights: • Electrolytic production of peroxydisulfuric acid (PDSA) with BDD anode. • PDSA yield enhanced by proper selection of cathode material. • Electro-scrubbing of SO_2 in presence of PDSA monitored by online FTIR analyzer. • 100% SO_2 removal was achieved for 25 ppm and 50 ppm in less than 10 min. - Abstract: Peroxydisulfuric acid oxidant (H_2S_2O_8) was electro-generated using boron doped diamond (BDD) anode in an undivided electrolytic cell under the optimized conditions and used for the oxidative removal of gaseous SO_2. The influence of the nature of cathode material on the formation yield of H_2S_2O_8 was investigated with Ti, Pt, Zr and DSA electrodes in a flow type electrolytic cell under batch recirculation mode. Among the various cathodes employed Ti exhibited a good performance and the formation yield was nearly doubled (0.19 M) compared to the reported value of 0.07 M. The optimization of electrode area ratio between the anode and cathode brought out the fact that for nearly 8 times smaller Ti cathode (8.75:1) the achieved yield was ∼65% higher than the 1:1 ratio of anode and cathode. The highest concentration of 6.8% (0.48 M) H_2S_2O_8 was seen for 35 cm"2 BDD anode with 4 cm"2 Ti at 20 °C with the measured redox potential value of +1200 mV. The oxidative removal of SO_2 in an electro-scrubbing column attached to the online production of peroxydisulfuric acid under the optimized conditions of cell parameters shows that SO_2 removal efficiency was nearly 100% for 25 and 50 ppm inlet concentrations and 96% for 100 ppm at the room temperature of 25 °C.

Effects of some factors on electro-osmotic dewatering of Laterite ...

African Journals Online (AJOL)

... effect on the EO process. The general effects were same for the two soil samples, but the rate of the effect varied, which implied that EO dewatering was site dependent. It was concluded that EO dewatering was a viable option for dewatering of tropical laterite. Keywords: Electro-osmosis, Soil Dewatering, Tropical Laterite, ...

An electro-thermal model and its application on a spiral-wound lithium ion battery with porous current collectors

International Nuclear Information System (INIS)

Ye, Yonghuang; Shi, Yixiang; Saw, Lip Huat; Tay, Andrew A.O.

2014-01-01

Highlights: • A local electro-thermal model is developed to verify the validity of a lump electro-thermal model. • Comparisons on edge effect of batteries with porous current collectors and batteries normal current collector foil. • Investigation on thermal performance of novel battery with porous current collector sheets. - Abstract: A local electro-thermal model for a spiral-wound lithium ion battery is developed to provide detailed and local insights of electrochemistry, transport phenomenon and heat transfer processes in spiral-wound geometries. The discharging potential, bulk heat generation rate, battery surface temperature and the temperature distribution within battery predicted by the model are used to verify a lumped electro-thermal model. The results show good agreement between the lumped electro-thermal model and the local electro-thermal model. The edge effect is investigated using the local electro-thermal model. And the results indicate that a novel battery with porous current collector sheets has a higher utilization rate of porous electrode materials than a commercial battery with normal current collector foils. The novel battery with porous current collector sheets is also investigated using the local electro-thermal model, simulation results show smaller liquid phase potential gradient and smaller liquid concentration gradient in the novel battery. The increased electrical resistance has minor effect on the overall heat generation within the battery when the porous current collector is employed, while it reduces the discharging potential of the battery

Electro-chemo-hydro-mechanical coupling in clayey media

International Nuclear Information System (INIS)

Lemaire, Th.

2004-12-01

The aim of this study is to understand coupled phenomena that occur in swelling porous materials like clays. Electro-chemo-hydro-mechanical contributions are taken into account to analyze transfers in such minerals. In a first part, a general discussion is proposed to introduce mineralogical and physico- chemical considerations of clayey media. An important objective of this chapter is to show the crucial role of the microstructure. In a second part is presented an imbibition test in a MX80 bentonite powder. The hydraulic diffusivity versus water content curve's decrease is explained thanks to a double porosity model that shows the progressive collapse of meso-pores due to swelling effects at the micro-scale. Thus a multi-scale analysis is necessary to well describe clayey media behaviour. The third chapter exposes such a multi-scale modelling (periodic homogenization). It is based on the double-layer theory and introduces an innovative concept of virtual electrolyte solution. First numerical results are given in a simple geometry (parallel platelets). In the next part are proposed numerical simulations of two kinds: response of the system to a chemical gradient and simulation of electro-osmosis. The end of this chapter puts into relief the necessity to integrate pH effects in the model. In the last part, chemical surface exchanges are incorporated in the modelling to understand pH and ionic force roles in electro-osmotic process. (author)

Electro-scrubbing volatile organic carbons in the air stream with a gas diffusion electrode

Energy Technology Data Exchange (ETDEWEB)

Yang Ji, E-mail: yangji@ecust.edu.cn [School of Resources and Environmental Engineering, State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, East China University of Science and Technology, Shanghai 200237 (China); School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Liu Kaichen; Jia Jinping; Cao Limei [School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)

2011-04-15

It is demonstrated that exposing the VOC air streams to the electro-scrubbing reactor with a gas diffusion electrode leads to an efficient removal of organics. The importance order of the influence factors on the electro-scrubbing reactor performance is: conductivity, voltage and air stream flow-rate. The effective conductivity and high voltages generally are beneficial to the removal process and the air flow-rate is not a significant factor compared with the other two, indicating that the reactor might have a consistently satisfying performance within a wide range of gas volumetric load. The mass transfer of both organics and oxygen in the reactor is estimated by mathematical model, and the calculation determines the concentration boundary conditions for the 2-ethoxyethyl acetate removal: if the 2-ethoxyethyl acetate concentration in the inflow air stream holds C{sub G,i} {<=} 0.7198 % , the removal in the electro-scrubbing reactor is electrochemical reaction controlled; if C{sub G,i} > 0.7198 % , the controlling step will be the oxygen mass transfer from the air to the liquid in the electro-scrubbing reactor. The Apparent Current Efficiency of the electro-scrubbing reactor was also determined using COD data, which is significantly higher than some commercial metal oxide electrodes, showing that the reactor is energy efficient and has the promise for the future scale-up.

An analytical solution for two-dimensional vacuum preloading combined with electro-osmosis consolidation using EKG electrodes

Science.gov (United States)

Qiu, Chenchen; Li, Yande

2017-01-01

China is a country with vast territory, but economic development and population growth have reduced the usable land resources in recent years. Therefore, reclamation by pumping and filling is carried out in eastern coastal regions of China in order to meet the needs of urbanization. However, large areas of reclaimed land need rapid drainage consolidation treatment. Based on past researches on how to improve the treatment efficiency of soft clay using vacuum preloading combined with electro-osmosis, a two-dimensional drainage plane model was proposed according to the Terzaghi and Esrig consolidation theory. However, the analytical solution using two-dimensional plane model was never involved. Current analytical solutions can’t have a thorough theoretical analysis of practical engineering and give relevant guidance. Considering the smearing effect and the rectangle arrangement pattern, an analytical solution is derived to describe the behavior of pore-water and the consolidation process by using EKG (electro-kinetic geo synthetics) materials. The functions of EKG materials include drainage, electric conduction and corrosion resistance. Comparison with test results is carried out to verify the analytical solution. It is found that the measured value is larger than the applied vacuum degree because of the stacking effect of the vacuum preloading and electro-osmosis. The trends of the mean measured value and the mean analytical value processes are comparable. Therefore, the consolidation model can accurately assess the change in pore-water pressure and the consolidation process during vacuum preloading combined with electro-osmosis. PMID:28771496

An analytical solution for two-dimensional vacuum preloading combined with electro-osmosis consolidation using EKG electrodes.

Directory of Open Access Journals (Sweden)

Yang Shen

Full Text Available China is a country with vast territory, but economic development and population growth have reduced the usable land resources in recent years. Therefore, reclamation by pumping and filling is carried out in eastern coastal regions of China in order to meet the needs of urbanization. However, large areas of reclaimed land need rapid drainage consolidation treatment. Based on past researches on how to improve the treatment efficiency of soft clay using vacuum preloading combined with electro-osmosis, a two-dimensional drainage plane model was proposed according to the Terzaghi and Esrig consolidation theory. However, the analytical solution using two-dimensional plane model was never involved. Current analytical solutions can't have a thorough theoretical analysis of practical engineering and give relevant guidance. Considering the smearing effect and the rectangle arrangement pattern, an analytical solution is derived to describe the behavior of pore-water and the consolidation process by using EKG (electro-kinetic geo synthetics materials. The functions of EKG materials include drainage, electric conduction and corrosion resistance. Comparison with test results is carried out to verify the analytical solution. It is found that the measured value is larger than the applied vacuum degree because of the stacking effect of the vacuum preloading and electro-osmosis. The trends of the mean measured value and the mean analytical value processes are comparable. Therefore, the consolidation model can accurately assess the change in pore-water pressure and the consolidation process during vacuum preloading combined with electro-osmosis.

Spin Polarisabilities and Compton Scattering from χEFT: Bridging QCD and Data

Science.gov (United States)

Griesshammer, Harald W.; McGovern, Judith A.; Phillips, Daniel R.

2017-01-01

Compton scattering from protons and neutrons probes their two-photon response in electric and magnetic fields of real photons, exploring the symmetries and interaction strengths of the internal degrees of freedom. With the scalar polarisabilities αE 1 and βM 1 now reasonably understood, the focus turns to the so-far poorly explored spin-polarisabilities. They parametrise the stiffness of the nucleon spin in external electro-magnetic fields, analogous to rotations of the polarisation of light by optically active media (bi-refringence/Faraday effect) and are particularly sensitive to the directional dependence of the πNγ interactions dictated by chiral symmetry and its breaking. This contribution addresses the potential of Chiral Effective Field Theory to relate between lattice QCD and ongoing or approved efforts at MAX-lab, HI γS and MAMI. We discuss high-intensity experiments with polarised targets and polarised beams which will allow the extraction of the spin-polarisabilities; χEFT predictions which indicate which observables for polarised protons, deuterons and 3 He are particularly sensitive; convergence, residual theoretical uncertainties and possibilities for improvement; and chiral extrapolations in mπ for lattice computations. Supported in part by UK STFC, US DOE and George Washington University.

Removal of PAHs from contaminated clayey soil by means of electro-osmosis

KAUST Repository

Lima, Ana T.; Kleingeld, Pieter J.; Heister, Katja; Loch, J.P. Gustav

2011-01-01

process that has been used for the mobilization and cleanup of contaminants in clayey soils with varying successes. The present study focuses on the remediation of a contaminated peaty clay soil, located in Olst - the Netherlands, by means of electro

Neuroprotective effects of electro acupuncture on hypoxic-ischemic encephalopathy in newborn rats Ass.

Science.gov (United States)

Xu, Tao; Li, Wenjie; Liang, Yiqun; Yang, Zhonghua; Liu, Jingdong; Wang, Yejun; Su, Nailun

2014-11-01

Hypoxic-ischemic encephalopathy (HIE) is a common and potentially devastating condition in the neonate, associated with high mortality and morbidity. Effective treatment options are limited and therefore alternative therapies such as acupuncture are increasingly used. Previous studies have shown that electro acupuncture promoted proliferation of neural progenitor cell and increased expression of neurotrophic factor in HIE. However, effects of electro acupuncture on downstream signaling pathways have been rarely researched. So, in the present study, we aimed to evaluate the neuroprotective effects of electro acupuncture on HIE and to further investigate the role of GDNF family receptor member RET and its key downstream PI3-K/Akt pathway in the process. A rat HIE model was constructed by the left common carotid artery (LCCA) ligation method in combination with hypoxic treatment. Considering that Baihui (GV20), Dazhui (GV14), Quchi (LI11) and Yongquan (KI1) are commonly used in clinics for stroke treatment and are easy to locate, we chose the above four acupoints as the combination for electro acupuncture treatment which was performed once a day for different time periods. Hematoxylin-eosin (HE) staining and transmission electron microscopy results showed that electro acupuncture could ameliorate neurologic damage and alleviate the degenerative changes of ultra structure of cortical neurons in rats subjected to HIE. And the longer acupuncture treatment lasted, the better its therapeutic effect would be. This was accompanied by gradually increased expression of GDNF family receptor RET at the mRNA level and its downstream signaling Akt at the protein level in the ischemic cortex. These findings suggest that electro acupuncture shows neuroprotective effects in HIE, which at least in part is attributed to activation of PI3-K/Akt signaling pathway.

Electro-optical switching of liquid crystals of graphene oxide

Science.gov (United States)

Song, Jang-Kun

Electric field effects on aqueous graphene-oxide (GO) dispersions are reviewed in this chapter. In isotropic and biphasic regimes of GO dispersions, in which the inter-particle friction is low, GO particles sensitively respond to the application of electric field, producing field-induced optical birefringence. The electro-optical sensitivity dramatically decreases as the phase transits to the nematic phase; the increasing inter-particle friction hinders the rotational switching of GO particles. The corresponding Kerr coefficient reaches the maximum near the isotropic to biphasic transition concentration, at which the Kerr coefficient is found be c.a. 1:8 · 10-5 mV-2, the highest value ever reported in all Kerr materials. The exceptionally large Kerr effect arises from the Maxwell- Wagner polarization of GO particles with an extremely large aspect ratio and a thick electrical double layer (EDL). The polarization sensitively depends on the ratio of surface and bulk conductivities in dispersions. As a result, low ion concentration in bulk solvent is highly required to achieve a quality electro-optical switching in GO dispersions. Spontaneous vinylogous carboxylic reaction in GO particles produces H+ ions, resulting in spontaneous degradation of electro-optical response with time, hence the removal of residual ions by using a centrifuge cleaning process significantly improves the electro-optical sensitivity. GO particle size is another important parameter for the Kerr coefficient and the response time. The best performance is observed in a GO dispersion with c.a. 0.5 μm mean size. Dielectrophoretic migration of GO particles can be also used to manipulate GO particles in solution. Using these unique features of GO dispersions, one can fabricate GO liquid crystal devices similar to conventional liquid crystal displays; the large Kerr effect allows fabricating a low power device working at extremely low electric fields.

Patient-controlled analgesia: therapeutic interventions using transdermal electro-activated and electro-modulated drug delivery.

Science.gov (United States)

Indermun, Sunaina; Choonara, Yahya E; Kumar, Pradeep; Du Toit, Lisa C; Modi, Girish; Luttge, Regina; Pillay, Viness

2014-02-01

Chronic pain poses a major concern to modern medicine and is frequently undertreated, causing suffering and disability. Patient-controlled analgesia, although successful, does have limitations. Transdermal delivery is the pivot to which analgesic research in drug delivery has centralized, especially with the confines of needle phobias and associated pain related to traditional injections, and the existing limitations associated with oral drug delivery. Highlighted within is the possibility of further developing transdermal drug delivery for chronic pain treatment using iontophoresis-based microneedle array patches. A concerted effort was made to review critically all available therapies designed for the treatment of chronic pain. The drug delivery systems developed for this purpose and nondrug routes are elaborated on, in a systematic manner. Recent developments and future goals in transdermal delivery as a means to overcome the individual limitations of the aforementioned delivery routes are represented as well. The approval of patch-like devices that contain both the microelectronic-processing mechanism and the active medicament in a small portable device is still awaited by the pharmaceutical industry. This anticipated platform may provide transdermal electro-activated and electro-modulated drug delivery systems a feasible attempt in chronic pain treatment. Iontophoresis has been proven an effective mode used to administer ionized drugs in physiotherapeutic, diagnostic, and dermatological applications and may be an encouraging probability for the development of devices and aids in the treatment of chronic pain. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association.

Pyroelectrically Induced Pyro-Electro-Chemical Catalytic Activity of BaTiO3 Nanofibers under Room-Temperature Cold–Hot Cycle Excitations

Directory of Open Access Journals (Sweden)

Yuntao Xia

2017-04-01

Full Text Available A pyro-electro-chemical catalytic dye decomposition using lead-free BaTiO3 nanofibers was realized under room-temperature cold–hot cycle excitation (30–47 °C with a high Rhodamine B (RhB decomposition efficiency ~99%, which should be ascribed to the product of pyro-electric effect and electrochemical redox reaction. Furthermore, the existence of intermediate product of hydroxyl radical in pyro-electro-chemical catalytic process was also observed. There is no significant decrease in pyro-electro-chemical catalysis activity after being recycled five times. The pyro-electrically induced pyro-electro-chemical catalysis provides a high-efficient, reusable and environmentally friendly technology to remove organic pollutants from water.

Spin and chirality effects in antler-topology processes at high energy e{sup +}e{sup -} colliders

Energy Technology Data Exchange (ETDEWEB)

Choi, S.Y. [Chonbuk National University, Department of Physics, Jeonbuk (Korea, Republic of); University of Pittsburgh, Department of Physics and Astronomy, Pittsburgh Particle physics, Astrophysics, and Cosmology Center, Pittsburgh, PA (United States); Christensen, N.D. [Illinois State University, Department of Physics, Normal, IL (United States); Salmon, D.; Wang, X. [University of Pittsburgh, Department of Physics and Astronomy, Pittsburgh Particle physics, Astrophysics, and Cosmology Center, Pittsburgh, PA (United States)

2015-10-15

We perform a model-independent investigation of spin and chirality correlation effects in the antler-topology processes e{sup +}e{sup -} → P{sup +}P{sup -} → (l{sup +}D{sup 0})(l{sup +} anti D{sup 0}) at highenergy e{sup +}e{sup -} colliders with polarized beams. Generally the production process e{sup +}e{sup -} → P{sup +}P{sup -} can occur not only through the s-channel exchange of vector bosons, V{sup 0}, including the neutral Standard Model (SM) gauge bosons, γ and Z, but also through the s- and t-channel exchanges of new neutral states, S{sup 0} and T{sup 0}, and the u-channel exchange of new doubly charged states, U{sup --}. The general set of (nonchiral) three-point couplings of the new particles and leptons allowed in a renormalizable quantum field theory is considered. The general spin and chirality analysis is based on the threshold behavior of the excitation curves for P{sup +}P{sup -} pair production in e{sup +}e{sup -} collisions with longitudinal- and transverse-polarized beams, the angular distributions in the production process and also the production-decay angular correlations. In the first step, we present the observables in the helicity formalism. Subsequently, we show how a set of observables can be designed for determining the spins and chiral structures of the new particles without any model assumptions. Finally, taking into account a typical set of approximately chiral invariant scenarios, we demonstrate how the spin and chirality effects can be probed experimentally at a high-energy e{sup +}e{sup -} collider. (orig.)

Theory-inspired development of organic electro-optic materials

Energy Technology Data Exchange (ETDEWEB)

Dalton, Larry R., E-mail: dalton@chem.washington.ed [Department of Chemistry, Bagley Hall 202D, Box 351700, University of Washington, Seattle, Washington 98195-1700 (United States); Department of Electrical Engineering, Bagley Hall 202D, Box 351700, University of Washington, Seattle, Washington 98195-1700 (United States)

2009-11-30

Real-time, time-dependent density functional theory (RTTDDFT) and pseudo-atomistic Monte Carlo-molecular dynamics (PAMCMD) calculations have been used in a correlated manner to achieve quantitative definition of structure/function relationships necessary for the optimization of electro-optic activity in organic materials. Utilizing theoretical guidance, electro-optic coefficients (at telecommunication wavelengths) have been increased to 500 pm/V while keeping optical loss to less than 2 dB/cm. RTTDDFT affords the advantage of permitting explicit treatment of time-dependent electric fields, both applied fields and internal fields. This modification has permitted the quantitative simulation of the variation of linear and nonlinear optical properties of chromophores and the electro-optic activity of materials with optical frequency and dielectric permittivity. PAMCMD statistical mechanical calculations have proven an effective means of treating the full range of spatially-anisotropic intermolecular electrostatic interactions that play critical roles in defining the degree of noncentrosymmetric order that is achieved by electric field poling of organic electro-optic materials near their glass transition temperatures. New techniques have been developed for the experimental characterization of poling-induced acentric order including a modification of variable angle polarization absorption spectroscopy (VAPAS) permitting a meaningful correlation of theoretical and experimental data related to poling-induced order for a variety of complex organic electro-optic materials.

Theory-inspired development of organic electro-optic materials

International Nuclear Information System (INIS)

Dalton, Larry R.

2009-01-01

Real-time, time-dependent density functional theory (RTTDDFT) and pseudo-atomistic Monte Carlo-molecular dynamics (PAMCMD) calculations have been used in a correlated manner to achieve quantitative definition of structure/function relationships necessary for the optimization of electro-optic activity in organic materials. Utilizing theoretical guidance, electro-optic coefficients (at telecommunication wavelengths) have been increased to 500 pm/V while keeping optical loss to less than 2 dB/cm. RTTDDFT affords the advantage of permitting explicit treatment of time-dependent electric fields, both applied fields and internal fields. This modification has permitted the quantitative simulation of the variation of linear and nonlinear optical properties of chromophores and the electro-optic activity of materials with optical frequency and dielectric permittivity. PAMCMD statistical mechanical calculations have proven an effective means of treating the full range of spatially-anisotropic intermolecular electrostatic interactions that play critical roles in defining the degree of noncentrosymmetric order that is achieved by electric field poling of organic electro-optic materials near their glass transition temperatures. New techniques have been developed for the experimental characterization of poling-induced acentric order including a modification of variable angle polarization absorption spectroscopy (VAPAS) permitting a meaningful correlation of theoretical and experimental data related to poling-induced order for a variety of complex organic electro-optic materials.

Internal Spin Control, Squeezing and Decoherence in Ensembles of Alkali Atomic Spins

Science.gov (United States)

Norris, Leigh Morgan

Large atomic ensembles interacting with light are one of the most promising platforms for quantum information processing. In the past decade, novel applications for these systems have emerged in quantum communication, quantum computing, and metrology. Essential to all of these applications is the controllability of the atomic ensemble, which is facilitated by a strong coupling between the atoms and light. Non-classical spin squeezed states are a crucial step in attaining greater ensemble control. The degree of entanglement present in these states, furthermore, serves as a benchmark for the strength of the atom-light interaction. Outside the broader context of quantum information processing with atomic ensembles, spin squeezed states have applications in metrology, where their quantum correlations can be harnessed to improve the precision of magnetometers and atomic clocks. This dissertation focuses upon the production of spin squeezed states in large ensembles of cold trapped alkali atoms interacting with optical fields. While most treatments of spin squeezing consider only the case in which the ensemble is composed of two level systems or qubits, we utilize the entire ground manifold of an alkali atom with hyperfine spin f greater than or equal to 1/2, a qudit. Spin squeezing requires non-classical correlations between the constituent atomic spins, which are generated through the atoms' collective coupling to the light. Either through measurement or multiple interactions with the atoms, the light mediates an entangling interaction that produces quantum correlations. Because the spin squeezing treated in this dissertation ultimately originates from the coupling between the light and atoms, conventional approaches of improving this squeezing have focused on increasing the optical density of the ensemble. The greater number of internal degrees of freedom and the controllability of the spin-f ground hyperfine manifold enable novel methods of enhancing squeezing. In

The Jellyfish: smart electro-active polymers for an autonomous distributed sensing node

Science.gov (United States)

Blottman, John B.; Richards, Roger T.

2006-05-01

The US Navy has recently placed emphasis on deployable, distributed sensors for Force Protection, Anti-Terrorism and Homeland Defense missions. The Naval Undersea Warfare Center has embarked on the development of a self-contained deployable node that is composed of electro-active polymers (EAP) for use in a covert persistent distributed surveillance system. Electro-Active Polymers (EAP) have matured to a level that permits their application in energy harvesting, hydrophones, electro-elastic actuation and electroluminescence. The problem to resolve is combining each of these functions into an autonomous sensing platform. The concept presented here promises an operational life several orders of magnitude beyond what is expected of a Sonobuoy due to energy conservation and harvesting, and at a reasonable cost. The embodiment envisioned is that of a deployed device resembling a jellyfish, made in most part of polymers, with the body encapsulating the necessary electronic processing and communications package and the tentacles of the jellyfish housing the sonar sensors. It will be small, neutrally buoyant, and will survey the water column much in the manner of a Cartesian Diver. By using the Electro-Active Polymers as artificial muscles, the motion of the jellyfish can be finely controlled. An increased range of detection and true node autonomy is achieved through volumetric array beamforming to focus the direction of interrogation and to null-out extraneous ambient noise.

Effect of different conductivity between the spin polarons on spin injection in a ferromagnet/organic semiconductor system

International Nuclear Information System (INIS)

Mi Yilin; Zhang Ming; Yan Hui

2008-01-01

Spin injection across ferromagnet/organic semiconductor system with finite width of the layers was studied theoretically considering spin-dependent conductivity in the organic-semiconductor. It was found that the spin injection efficiency is directly dependent on the difference between the conductivity of the up-spin and down-spin polarons in the spin-injected organic system. Furthermore, the finite width of the structure, interfacial electrochemical-potential and conductivity mismatch have great influence on the spin injection process across ferromagnet/organic semiconductor interface

Modelling electro-active polymers with a dispersion-type anisotropy

Science.gov (United States)

Hossain, Mokarram; Steinmann, Paul

2018-02-01

We propose a novel constitutive framework for electro-active polymers (EAPs) that can take into account anisotropy with a chain dispersion. To enhance actuation behaviour, particle-filled EAPs become promising candidates nowadays. Recent studies suggest that particle-filled EAPs, which can be cured under an electric field during the manufacturing time, do not necessarily form perfect anisotropic composites, rather they create composites with dispersed chains. Hence in this contribution, an electro-mechanically coupled constitutive model is devised that considers the chain dispersion with a probability distribution function in an integral form. To obtain relevant quantities in discrete form, numerical integration over the unit sphere is utilized. Necessary constitutive equations are derived exploiting the basic laws of thermodynamics that result in a thermodynamically consistent formulation. To demonstrate the performance of the proposed electro-mechanically coupled framework, we analytically solve a non-homogeneous boundary value problem, the extension and inflation of an axisymmetric cylindrical tube under electro-mechanically coupled load. The results capture various electro-mechanical couplings with the formulation proposed for EAP composites.

Drying brick masonry by electro-osmosis

DEFF Research Database (Denmark)

Ottosen, Lisbeth M.; Rörig-Dalgaard, Inge

2006-01-01

When a fine grained, porous medium is applied an electric DC field, transport of matter occurs, and the transport mechanism in focus of the present study is electro-osmosis, which is transport of water. In laboratory it was shown possible to transport water inside a brick and brick/mortar system...... movement of water towards the cathode was seen. Thus the basis for utilizing the electro-osmotic effect for drying brick masonry is present, but proper electrodes still needs to be developed....

Analytic expression for the giant fieldlike spin torque in spin-filter magnetic tunnel junctions

Science.gov (United States)

Tang, Y.-H.; Huang, Z.-W.; Huang, B.-H.

2017-08-01

We propose analytic expressions for fieldlike, T⊥, and spin-transfer, T∥, spin torque components in the spin-filter-based magnetic tunnel junction (SFMTJ), by using the single-band tight-binding model with the nonequilibrium Keldysh formalism. In consideration of multireflection processes between noncollinear magnetization of the spin-filter (SF) barrier and the ferromagnetic (FM) electrode, the central spin-selective SF barrier plays an active role in the striking discovery T⊥≫T∥ , which can be further identified by the unusual barrier thickness dependence of giant T⊥. Our general expressions reveal the sinusoidal angular dependence of both spin torque components, even in the presence of the SF barrier.

Beam Splitter for Spin Waves in Quantum Spin Network

OpenAIRE

Yang, S.; Song, Z.; Sun, C. P.

2005-01-01

We theoretically design and analytically study a controllable beam splitter for the spin wave propagating in a star-shaped (e.g., a $Y$-shaped beam) spin network. Such a solid state beam splitter can display quantum interference and quantum entanglement by the well-aimed controls of interaction on nodes. It will enable an elementary interferometric device for scalable quantum information processing based on the solid system.

Exact solution of the mixed spin-1/2 and spin-S Ising-Heisenberg diamond chain

Directory of Open Access Journals (Sweden)

L. Čanová

2009-01-01

Full Text Available The geometric frustration in a class of the mixed spin-1/2 and spin-S Ising-Heisenberg diamond chains is investigated by combining three exact analytical techniques: Kambe projection method, decoration-iteration transformation and transfer-matrix method. The ground state, the magnetization process and the specific heat as a function of the external magnetic field are particularly examined for different strengths of the geometric frustration. It is shown that the increase of the Heisenberg spin value S raises the number of intermediate magnetization plateaux, which emerge in magnetization curves provided that the ground state is highly degenerate on behalf of a sufficiently strong geometric frustration. On the other hand, all intermediate magnetization plateaux merge into a linear magnetization versus magnetic field dependence in the limit of classical Heisenberg spin S → ∞. The enhanced magnetocaloric effect with cooling rate exceeding the one of paramagnetic salts is also detected when the disordered frustrated phase constitutes the ground state and the external magnetic field is small enough.

Radiation resistance of electro-optic polymer-based modulators

International Nuclear Information System (INIS)

Taylor, Edward W.; Nichter, James E.; Nash, Fazio D.; Haas, Franz; Szep, Attila A.; Michalak, Richard J.; Flusche, Brian M.; Cook, Paul R.; McEwen, Tom A.; McKeon, Brian F.; Payson, Paul M.; Brost, George A.; Pirich, Andrew R.; Castaneda, Carlos; Tsap, Boris; Fetterman, Harold R.

2005-01-01

Mach-Zehnder interferometric electro-optic polymer modulators composed of highly nonlinear phenyltetraene bridge-type chromophores within an amorphous polycarbonate host matrix were investigated for their resistance to gamma rays and 25.6 MeV protons. No device failures were observed and the majority of irradiated modulators exhibited decreases in half-wave voltage and optical insertion losses compared to nonirradiated control samples undergoing aging processes. Irradiated device responses were attributed to scission, cross-linking, and free volume processes. The data suggests that strongly poled devices are less likely to de-pole under the influence of ionizing radiation

Spin-wave interference patterns created by spin-torque nano-oscillators for memory and computation

International Nuclear Information System (INIS)

Macia, Ferran; Kent, Andrew D; Hoppensteadt, Frank C

2011-01-01

Magnetization dynamics in nanomagnets has attracted broad interest since it was predicted that a dc current flowing through a thin magnetic layer can create spin-wave excitations. These excitations are due to spin momentum transfer, a transfer of spin angular momentum between conduction electrons and the background magnetization, that enables new types of information processing. Here we show how arrays of spin-torque nano-oscillators can create propagating spin-wave interference patterns of use for memory and computation. Memristic transponders distributed on the thin film respond to threshold tunnel magnetoresistance values, thereby allowing spin-wave detection and creating new excitation patterns. We show how groups of transponders create resonant (reverberating) spin-wave interference patterns that may be used for polychronous wave computation and information storage.

Effect of temperature on the morphology and electro-optical properties of liquid crystal physical gel

International Nuclear Information System (INIS)

Leaw, W.L.; Mamat, C.R.; Triwahyono, S.; Jalil, A.A.; Bidin, N.

2016-01-01

Liquid crystal physical gels were (thermally) prepared with cholesteryl stearate as a gelator in nematic liquid crystal, 4-cyano-4′-pentylbiphenyl. The electro-optical performance of liquid crystal physical gels is almost entirely dependent on the gels' inherent morphology. This study involved an empirical investigation of the relationships among all of the gelation temperature, morphology, and electro-optical properties. Besides continuous cooling at room temperature, isothermal cooling was also performed at both 18 and 0 °C, corresponding to near-solid and solid phases of 4-cyano-4′-pentylbiphenyl respectively. Nevertheless, the liquid crystal physical gel was also isothermally rapidly cooled using liquid nitrogen. Polarizing optical microscopy showed that the gel structure became thinner when isothermal cooling was carried out. These thinner gel aggregates then interconnected to form larger liquid crystal domains. Moreover, it was also revealed that the gel networks were randomized. Electron spin resonance results showed that the liquid crystal director orientation was severely randomized in the presence of gel networks. Conversely, isothermal cooling using liquid nitrogen generated a higher liquid crystal director orientation order. The 6.0 wt% cholesteryl stearate/4-cyano-4′-pentylbiphenyl physical gel that was isothermally cooled using liquid nitrogen showed the lowest response time in a twisted nematic mode optical cell. - Graphical abstract: Liquid crystal physical gel was prepared using nematic liquid crystal, 4-cyano-4′-pentylbiphenyl and cholesteryl stearate as gelator. Isothermal cooling at lower temperature produced thinner gel network and larger liquid crystal domain. - Highlights: • 5CB nematic liquid crystal was successfully gelled by cholesteryl stearate gelator. • The morphology of gel network was controlled by different cooling conditions. • Thinner gel network was formed by the rapid cooling using liquid nitrogen. • Enhanced

Effect of temperature on the morphology and electro-optical properties of liquid crystal physical gel

Energy Technology Data Exchange (ETDEWEB)

Leaw, W.L. [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310, UTM Johor Bahru, Johor (Malaysia); Mamat, C.R., E-mail: che@kimia.fs.utm.my [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310, UTM Johor Bahru, Johor (Malaysia); Triwahyono, S. [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310, UTM Johor Bahru, Johor (Malaysia); Jalil, A.A. [Department of Chemical Engineering, Faculty of Chemical and Energy Engineering, Universiti Teknologi Malaysia, 81310, UTM Johor Bahru, Johor (Malaysia); Centre of Hydrogen Energy, Institute of Future Energy, Univerisiti Teknologi Malaysia, 81310, UTM Johor Bahru, Johor (Malaysia); Bidin, N. [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310, UTM Johor Bahru, Johor (Malaysia)

2016-12-01

Liquid crystal physical gels were (thermally) prepared with cholesteryl stearate as a gelator in nematic liquid crystal, 4-cyano-4′-pentylbiphenyl. The electro-optical performance of liquid crystal physical gels is almost entirely dependent on the gels' inherent morphology. This study involved an empirical investigation of the relationships among all of the gelation temperature, morphology, and electro-optical properties. Besides continuous cooling at room temperature, isothermal cooling was also performed at both 18 and 0 °C, corresponding to near-solid and solid phases of 4-cyano-4′-pentylbiphenyl respectively. Nevertheless, the liquid crystal physical gel was also isothermally rapidly cooled using liquid nitrogen. Polarizing optical microscopy showed that the gel structure became thinner when isothermal cooling was carried out. These thinner gel aggregates then interconnected to form larger liquid crystal domains. Moreover, it was also revealed that the gel networks were randomized. Electron spin resonance results showed that the liquid crystal director orientation was severely randomized in the presence of gel networks. Conversely, isothermal cooling using liquid nitrogen generated a higher liquid crystal director orientation order. The 6.0 wt% cholesteryl stearate/4-cyano-4′-pentylbiphenyl physical gel that was isothermally cooled using liquid nitrogen showed the lowest response time in a twisted nematic mode optical cell. - Graphical abstract: Liquid crystal physical gel was prepared using nematic liquid crystal, 4-cyano-4′-pentylbiphenyl and cholesteryl stearate as gelator. Isothermal cooling at lower temperature produced thinner gel network and larger liquid crystal domain. - Highlights: • 5CB nematic liquid crystal was successfully gelled by cholesteryl stearate gelator. • The morphology of gel network was controlled by different cooling conditions. • Thinner gel network was formed by the rapid cooling using liquid nitrogen. �

Melt-spin processing of YBa2Cu3O7-x

International Nuclear Information System (INIS)

Folkerts, T.J.; Kramer, M.J.; McCallum, R.W.; Iowa State Univ. of Science and Technology, Ames, IA

1991-01-01

We introduce a novel containerless melt-spin processing technique for YBa 2 Cu 3 O 7-x using prereacted oxide powders which are rapidly melted and subsequentially quenched in a controlled atmosphere. This results in flakes with typical dimensions of 3000x150x15 μm 3 . Powder XRD indicates that all samples contain Y 2 O 3 , but that the Ba--Cu--O phases present depend on the processing parameters. SEM and TEM studies show these phases are finely dispersed: the typical grain size for Y 2 O 3 is 1--2 μm, and for the Ba--Cu--O phases it is <0.5 μm

Optimal process parameters for phosphorus spin-on-doping of germanium

Energy Technology Data Exchange (ETDEWEB)

Boldrini, Virginia [Dipartimento di Fisica e Astronomia, Università degli Studi di Padova, Via Marzolo 8, I-35131 Padova (Italy); INFN-LNL, Viale dell’Università 2, I-35020 Legnaro, Padova (Italy); Carturan, Sara Maria, E-mail: sara.carturan@lnl.infn.it [Dipartimento di Fisica e Astronomia, Università degli Studi di Padova, Via Marzolo 8, I-35131 Padova (Italy); INFN-LNL, Viale dell’Università 2, I-35020 Legnaro, Padova (Italy); Maggioni, Gianluigi; Napolitani, Enrico [Dipartimento di Fisica e Astronomia, Università degli Studi di Padova, Via Marzolo 8, I-35131 Padova (Italy); INFN-LNL, Viale dell’Università 2, I-35020 Legnaro, Padova (Italy); Napoli, Daniel Ricardo [INFN-LNL, Viale dell’Università 2, I-35020 Legnaro, Padova (Italy); Camattari, Riccardo [INFN Sezione di Ferrara, Dipartimento di Fisica, Università di Ferrara, Via Saragat 1, 44122, Ferrara (Italy); De Salvador, Davide [Dipartimento di Fisica e Astronomia, Università degli Studi di Padova, Via Marzolo 8, I-35131 Padova (Italy); INFN-LNL, Viale dell’Università 2, I-35020 Legnaro, Padova (Italy)

2017-01-15

Highlights: • Optimized protocol for the application of phosphorus spin-on-doping to Ge surface. • Homogeneous n-type Ge layers, fully electrically active, are obtained. • Crucial parameters for SOD curing are relative humidity, time and temperature. • Characterization of Ge loss from the surface into the SOD film by diffusion. • Spike annealing in standard tube chamber furnace are performed. - Abstract: The fabrication of homogeneously doped germanium layers characterized by total electrical activation is currently a hot topic in many fields, such as microelectronics, photovoltaics, optics and radiation detectors. Phosphorus spin-on-doping technique has been implemented on Ge wafers, by developing a protocol for the curing process and subsequent diffusion annealing for optimal doping. Parameters such as relative humidity and curing time turned out to affect the surface morphology, the degree of reticulation reached by the dopant source and the amount of dopant available for diffusion. After spike annealing in a conventional furnace, diffusion profiles and electrical properties have been measured. Ge loss from the surface during high-temperature annealing, due to diffusion into the source film, has been observed and quantified.

A Survey on the Reliability of Power Electronics in Electro-Mobility Applications

DEFF Research Database (Denmark)

Gadalla, Brwene Salah Abdelkarim; Schaltz, Erik; Blaabjerg, Frede

2015-01-01

Reliability is an important issue in the field of power electronics since most of the electrical energy is today processed by power electronics. In most of the electro-mobility applications, e.g. electric and hybridelectric vehicles, power electronic are commonly used in very harsh environment...... and extending the service lifetime as well. Research within power electronics is of high interest as it has an important impact in the industry of the electro-mobility applications. According to the aforementioned explanations, this paper will provide an overview of the common factors (thermal cycles, power...... cycles, vibrations, voltage stress and current ripple stress) affecting the reliability of power electronics in electromobility applications. Also, the researchers perspective is summarized from 2001 to 2015....

Leaching of manganese from electrolytic manganese residue by electro-reduction.

Science.gov (United States)

Shu, Jiancheng; Liu, Renlong; Liu, Zuohua; Chen, Hongliang; Tao, Changyuan

2017-08-01

In this study, an improved process for leaching manganese from electrolytic manganese residue (EMR) by electro-reduction was developed. The mechanisms of the electro-reduction leaching were investigated through X-ray diffraction, scanning electron microscopy, X-ray fluorescence, and Brunauer Emmett Teller. The results show that the electric field could change the surface charge distribution of EMR particles, and the high-valent manganese can be reduced by electric field. The leaching efficient of manganese reached 84.1% under the optimal leaching condition: 9.2 wt% H 2 SO 4 , current density of 25 mA/cm 2 , solid-to-liquid ratio of 1:5, and leaching time for 1 h. It is 37.9% higher than that attained without an electric field. Meanwhile, the manganese content in EMR decreased from 2.57% to 0.48%.

High-speed Si/GeSi hetero-structure Electro Absorption Modulator.

Science.gov (United States)

Mastronardi, L; Banakar, M; Khokhar, A Z; Hattasan, N; Rutirawut, T; Bucio, T Domínguez; Grabska, K M; Littlejohns, C; Bazin, A; Mashanovich, G; Gardes, F Y

2018-03-19

The ever-increasing demand for integrated, low power interconnect systems is pushing the bandwidth density of CMOS photonic devices. Taking advantage of the strong Franz-Keldysh effect in the C and L communication bands, electro-absorption modulators in Ge and GeSi are setting a new standard in terms of device footprint and power consumption for next generation photonics interconnect arrays. In this paper, we present a compact, low power electro-absorption modulator (EAM) Si/GeSi hetero-structure based on an 800 nm SOI overlayer with a modulation bandwidth of 56 GHz. The device design and fabrication tolerant process are presented, followed by the measurement analysis. Eye diagram measurements show a dynamic ER of 5.2 dB at a data rate of 56 Gb/s at 1566 nm, and calculated modulator power is 44 fJ/bit.

Selective coupling of individual electron and nuclear spins with integrated all-spin coherence protection

Science.gov (United States)

Terletska, Hanna; Dobrovitski, Viatcheslav

2015-03-01

The electron spin of the NV center in diamond is a promising platform for spin sensing. Applying the dynamical decoupling, the NV electron spin can be used to detect the individual weakly coupled carbon-13 nuclear spins in diamond and employ them for small-scale quantum information processing. However, the nuclear spins within this approach remain unprotected from decoherence, which ultimately limits the detection and restricts the fidelity of the quantum operation. Here we investigate possible schemes for combining the resonant decoupling on the NV spin with the decoherence protection of the nuclear spins. Considering several schemes based on pulse and continuous-wave decoupling, we study how the joint electron-nuclear spin dynamics is affected. We identify regimes where the all-spin coherence protection improves the detection and manipulation. We also discuss potential applications of the all-spin decoupling for detecting spins outside diamond, with the purpose of implementing the nanoscale NMR. This work was supported by the US Department of Energy Basic Energy Sciences (Contract No. DE-AC02-07CH11358).

Removal of PAHs from contaminated calyey soil by means of electro-osmosis

NARCIS (Netherlands)

Lima, A.T.; Kleingeld, P.J.; Heister, K.; Loch, J.P.G.

2011-01-01

The removal of polycyclic aromatic hydrocarbons (PAHs) from clayey soils is an intricate task. The low porosity of compacted clayey soil hinders bacterial activity and makes convective removal by hydraulic flow impossible. Electro-osmosis is a process that has been used for the mobilization and

Spin-flip tunneling in quantum dots

Energy Technology Data Exchange (ETDEWEB)

Schreiber, Lars; Braakman, Floris; Meunier, Tristan; Calado, Victor; Vandersypen, Lieven [Kavli Institute of NanoScience, Delft (Netherlands); Wegscheider, Werner [Institute for Experimental and Applied Physics, University of Regensburg (Germany)

2010-07-01

Electron spins in a gate-defined double quantum dot formed in a GaAs/(Al,Ga)As 2DEG are promising candidates for quantum information processing as coherent single spin rotation and spin swap has been demonstrated recently. In this system we investigate the two-electron spin dynamics in the presence of microwaves (5.20 GHz) applied to one side gate. During microwave excitation we observe characteristic photon assisted tunneling (PAT) peaks at the (1,1) to (0,2) charge transition. Some of the PAT peaks are attributed to photon tunneling events between the singlet S(0,2) and the singlet S(1,1) states, a spin-conserving transition. Surprisingly, other PAT peaks stand out by their different external magnetic field dependence. They correspond to tunneling involving a spin-flip, from the (0,2) singlet to a (1,1) triplet. The full spectrum of the observed PAT lines is captured by simulations. This process offers novel possibilities for 2-electron spin manipulation and read-out.

Lambda polarization in association K+ -Lambda electro-production

CERN Document Server

Teodorescu, L; Angelescu, T; Baker, O K; Ent, R; Guidal, M; Laget, J M; Mitchell, J; Niculescu, G; Vanderhaeghen, V; William, R

1999-01-01

The result of a feasibility study to measure the Lambda polarization in associated K+ -Lambda electro production is presented. This measurement was performed in the experimental Hall C at Jefferson Lab. The scattered electron was detected in the HMS spectrometer, and the electro-produced kaon and the proton from the Lambda -> ppi- decay were both detected in the SOS spectrometer. This quantity is very sensitive to the elementary p(e,e'K) [capital Lambda, Greek] process and gives information on resonance production, and Regge exchange, among others. The result presented was measured at Q2=1.50 (GeV/c)2 and cos [straight theta, small theta, Greek] K [small gamma, Greek] CM=14 sup o. The limits of the [capital Lambda, Greek] polarization, with respect to the p [small gamma, Greek] x pK axis, were found to be -0.21 and +0.89 with a confidence level of 68%. The result is compared to theoretical predictions based on an effective hadronic field Lagrangian model and a Regge framework model.

A Fast Electro-Thermal Co-Simulation Modeling Approach for SiC Power MOSFETs

DEFF Research Database (Denmark)

Ceccarelli, Lorenzo; Bahman, Amir Sajjad; Iannuzzo, Francesco

2017-01-01

The purpose of this work is to propose a novel electro-thermal co-simulation approach for the new generation of SiC MOSFETs, by development of a PSpice-based compact and physical SiC MOSFET model including temperature dependency of several parameters and a Simulink-based thermal network. The PSpice...... the FEM simulation of the DUT’s structure, performed in ANSYS Icepack. A MATLAB script is used to process the simulation data and feed the needed settings and parameters back into the simulation. The parameters for a CREE 1.2 kV/30 A SiC MOSFET have been identified and the electro-thermal model has been...

Magneto-optic and electro-optic modulators

International Nuclear Information System (INIS)

Hutchinson, D.P.; Ma, C.H.; Price, T.R.; Staats, P.A.; Sluis, K.L.V.

1982-01-01

An important aspect of the Faraday rotation diagnostic for tokamak plasma measurement has been the development of suitable polarization modulators for submillimeter wavelength. The problems are to obtain high optical transmission and fast modulation frequencies. In ORNL, the authors have developed both a magneto-optic and an electro-optic submillimeter-wave modulators. These devices have been operated at modulation frequency of approximately 100 kHz, and both have high transmission. The original magneto-optic modulator consists of a 3 mm thick by 1.4 cm diameter 2-111 ferrite disk mounted at the center of an air core coil. Recently, a new ferrite modulator has been tested, which allows a much higher modulation frequency than the original device. A laboratory set-up designed to simulate a plasma heterodyne interferometer/polarimeter experiment has been used to determine the modulator characteristics. A mechanical polarization rotor was used to simulate the rotation by plasma. The transmission of the ferrite disk was 80 % at a wavelength of 0.447 mm. The authors have also performed preliminary measurement on an electro-optic modulator first demonstrated by Fetterman at Lincoln Laboratory, U.S. This device is a classical electro-optic modulator using a cryogenically cooled (4.2 K) LiTaO 3 crystal. Experiments are underway to determine the electro-optic properties of the crystal over the temperature range from 4.2 K to 77 K and over the range of wavelength from 0.118 mm to 0.447 mm. (Wakatsuki, Y.)

Spin and chirality effects in antler-topology processes at high energy e{sup +}e{sup -} colliders

Energy Technology Data Exchange (ETDEWEB)

Choi, S. Y. [Department of Physics, Chonbuk National University, 561-756, Jeonbuk (Korea, Republic of); Department of Physics and Astronomy, Pittsburgh Particle physics, Astrophysics, and Cosmology Center, University of Pittsburgh, 15260, Pittsburgh, PA (United States); Christensen, N. D. [Department of Physics, Illinois State University, 61790, Normal, IL (United States); Salmon, D.; Wang, X., E-mail: xiw77@pitt.edu [Department of Physics and Astronomy, Pittsburgh Particle physics, Astrophysics, and Cosmology Center, University of Pittsburgh, 15260, Pittsburgh, PA (United States)

2015-10-06

We perform a model-independent investigation of spin and chirality correlation effects in the antler-topology processes e{sup +}e{sup -}→P{sup +}P{sup -}→(ℓ{sup +}D{sup 0})(ℓ{sup -}D{sup -bar0}) at high-energy e{sup +}e{sup -} colliders with polarized beams. Generally the production process e{sup +}e{sup -}→P{sup +}P{sup -} can occur not only through the s-channel exchange of vector bosons, V{sup 0}, including the neutral Standard Model (SM) gauge bosons, γ and Z, but also through the s- and t-channel exchanges of new neutral states, S{sup 0} and T{sup 0}, and the u-channel exchange of new doubly charged states, U{sup --}. The general set of (non-chiral) three-point couplings of the new particles and leptons allowed in a renormalizable quantum field theory is considered. The general spin and chirality analysis is based on the threshold behavior of the excitation curves for P{sup +}P{sup -} pair production in e{sup +}e{sup -} collisions with longitudinal- and transverse-polarized beams, the angular distributions in the production process and also the production-decay angular correlations. In the first step, we present the observables in the helicity formalism. Subsequently, we show how a set of observables can be designed for determining the spins and chiral structures of the new particles without any model assumptions. Finally, taking into account a typical set of approximately chiral invariant scenarios, we demonstrate how the spin and chirality effects can be probed experimentally at a high-energy e{sup +}e{sup -} collider.

Electric-field effects in optically generated spin transport

International Nuclear Information System (INIS)

Miah, M. Idrish

2009-01-01

Transport of spin-polarized electrons in semiconductors is studied experimentally. Spins are generated by optical excitation because of the selection rules governing optical transitions from heavy-hole and light-hole states to conduction-band states. Experiments designed for the control of spins in semiconductors investigate the bias-dependent spin transport process and detect the spin-polarized electrons during transport. A strong bias dependence is observed. The electric-field effects on the spin-polarized electron transport are also found to be depended on the excitation photon energy and temperature. Based on a field-dependent spin relaxation mechanism, the electric-field effects in the transport process are discussed.

Electric-field effects in optically generated spin transport

Energy Technology Data Exchange (ETDEWEB)

Miah, M. Idrish [Nanoscale Science and Technology Centre and School of Biomolecular and Physical Sciences, Griffith University, Nathan, Brisbane, QLD 4111 (Australia); Department of Physics, University of Chittagong, Chittagong 4331 (Bangladesh)], E-mail: m.miah@griffith.edu.au

2009-05-25

Transport of spin-polarized electrons in semiconductors is studied experimentally. Spins are generated by optical excitation because of the selection rules governing optical transitions from heavy-hole and light-hole states to conduction-band states. Experiments designed for the control of spins in semiconductors investigate the bias-dependent spin transport process and detect the spin-polarized electrons during transport. A strong bias dependence is observed. The electric-field effects on the spin-polarized electron transport are also found to be depended on the excitation photon energy and temperature. Based on a field-dependent spin relaxation mechanism, the electric-field effects in the transport process are discussed.

Spin crossover and high spin filtering behavior in Co-Pyridine and Co-Pyrimidine molecules

Science.gov (United States)

Wen, Zhongqian; Zhou, Liping; Cheng, Jue-Fei; Li, Shu-Jin; You, Wen-Long; Wang, Xuefeng

2018-03-01

We present a theoretical study on a series of cobalt complexes, which are constructed with cobalt atoms and pyridine/pyrimidine rings, using density functional theory. We investigate the structural and electric transport properties of spin crossover (SCO) Co complex with two spin states, namely low-spin configuration [LS] and high-spin configuration [HS]. Energy analyses of the two spin states imply that the SCO Co-Pyridine2 and Co-Pyrimidine2 complexes may display a spin transition process accompanied by a geometric modification driven by external stimuli. A nearly perfect spin filtering effect is observed in the Co-Pyrimidine2 complex with [HS] state. In addition, we also discover the contact-dependent transmission properties of Co-Pyridine2. These findings indicate that SCO Co complexes are promising materials for molecular spintronic devices.

Electro sinter forging of titanium disks

DEFF Research Database (Denmark)

Cannella, Emanuele; Nielsen, Chris Valentin; Bay, Niels Oluf

by measuring the electrical resistance during the sintering process [5], since low electrical resistance corresponds to high density. It is, however, necessary to be aware that increased temperature, on the other hand, increases the resistance. SEM micrographs and Computed Tomography (CT) are carried out......Electro sinter forging (ESF) is a new sintering process based on the principle of electrical Joule heating. In the present work, middle frequency direct current (MFDC) was flowing through the powder compact, which was under mechanical pressure. The main parameters are the high electrical current......, up to 10 kA, and the low voltage, 1-2 V, resulting in heat generation in the powder. Figure 1 shows the experimental setup. The punches were made of a conductive material; namely a copper alloy. The die, which has to be electrically insulating, was made of alumina. The ESF process takes 3-4s...

Hydrogel Walkers with Electro-Driven Motility for Cargo Transport.

Science.gov (United States)

Yang, Chao; Wang, Wei; Yao, Chen; Xie, Rui; Ju, Xiao-Jie; Liu, Zhuang; Chu, Liang-Yin

2015-08-28

In this study, soft hydrogel walkers with electro-driven motility for cargo transport have been developed via a facile mould-assisted strategy. The hydrogel walkers consisting of polyanionic poly(2-acrylamido-2-methylpropanesulfonic acid-co-acrylamide) exhibit an arc looper-like shape with two "legs" for walking. The hydrogel walkers can reversibly bend and stretch via repeated "on/off" electro-triggers in electrolyte solution. Based on such bending/stretching behaviors, the hydrogel walkers can move their two "legs" to achieve one-directional walking motion on a rough surface via repeated "on/off" electro-triggering cycles. Moreover, the hydrogel walkers loaded with very heavy cargo also exhibit excellent walking motion for cargo transport. Such hydrogel systems create new opportunities for developing electro-controlled soft systems with simple design/fabrication strategies in the soft robotic field for remote manipulation and transportation.

Electro Spray Method for Flexible Display

Science.gov (United States)

2016-05-12

AFRL-AFOSR-JP-TR-2016-0095 Electro Spray Method for Flexible Display Yukiharu Uraoka NARA INSTITUTE OF SCIENCE AND TECHNOLOGY Final Report 11/26/2016...DATES COVERED (From - To)  20 Mar 2013 to 19 May 2016 4. TITLE AND SUBTITLE Electro Spray Method for Flexible Display 5a.  CONTRACT NUMBER 5b.  GRANT...NUMBER FA2386-13-1-4024 5c.  PROGRAM ELEMENT NUMBER 61102F 6. AUTHOR(S) Yukiharu Uraoka 5d.  PROJECT NUMBER 5e.  TASK NUMBER 5f.   WORK UNIT NUMBER 7

Simultaneous decomplexation in blended Cu(II)/Ni(II)-EDTA systems by electro-Fenton process using iron sacrificing electrodes.

Science.gov (United States)

Zhao, Zilong; Dong, Wenyi; Wang, Hongjie; Chen, Guanhan; Tang, Junyi; Wu, Yang

2018-05-15

This research explored the application of electro-Fenton (E-Fenton) technique for the simultaneous decomplexation in blended Cu(II)/Ni(II)-EDTA systems by using iron sacrificing electrodes. Standard discharge (0.3 mg L -1 for Cu and 0.1 mg L -1 for Ni in China) could be achieved after 30 min reaction under the optimum conditions (i.e. initial solution pH of 2.0, H 2 O 2 dosage of 6 mL L -1  h -1 , current density of 20 mA/cm 2 , inter-electrode distance of 2 cm, and sulfate electrolyte concentration of 2000 mg L -1 ). The distinct differences in apparent kinetic rate constants (k app ) and intermediate removal efficiencies corresponding to mere and blended systems indicated the mutual promotion effect toward the decomplexation between Cu(II) and Ni(II). Massive accumulation of Fe(Ⅲ) favored the further removal of Cu(II) and Ni(II) by metal ion substitution. Species distribution results demonstrated that the decomplexation of metal-EDTA in E-Fenton process was mainly contributed to the combination of various reactions, including Fenton reaction together with the anodic oxidation, electro-coagulation (E-coagulation) and electrodeposition. Unlike hypophosphite and citrate, the presence of chlorine ion displayed favorable effects on the removal efficiencies of Cu(II) and Ni(II) at low dosage, but facilitated the ammonia nitrogen (NH 4 + -N) removal only at high dosage. Copyright © 2018 Elsevier B.V. All rights reserved.

Electro-Optical Laser Technology. Curriculum Utilization. Final Report.

Science.gov (United States)

Nawn, John H.

This report describes a program to prepare students for employment as laser technicians and laser operators and to ensure that they have the necessary skills required by the industry. The objectives are to prepare a curriculum and syllabus for an associate degree program in Electro-Optical Laser Technology. The 2-year Electro-Optical Laser program…

Entangled spins and ghost-spins

Directory of Open Access Journals (Sweden)

Dileep P. Jatkar

2017-09-01

Full Text Available We study patterns of quantum entanglement in systems of spins and ghost-spins regarding them as simple quantum mechanical toy models for theories containing negative norm states. We define a single ghost-spin as in [20] as a 2-state spin variable with an indefinite inner product in the state space. We find that whenever the spin sector is disentangled from the ghost-spin sector (both of which could be entangled within themselves, the reduced density matrix obtained by tracing over all the ghost-spins gives rise to positive entanglement entropy for positive norm states, while negative norm states have an entanglement entropy with a negative real part and a constant imaginary part. However when the spins are entangled with the ghost-spins, there are new entanglement patterns in general. For systems where the number of ghost-spins is even, it is possible to find subsectors of the Hilbert space where positive norm states always lead to positive entanglement entropy after tracing over the ghost-spins. With an odd number of ghost-spins however, we find that there always exist positive norm states with negative real part for entanglement entropy after tracing over the ghost-spins.

Electro-Optics/Low Observables Laboratory

Data.gov (United States)

Federal Laboratory Consortium — The Electro-Optics/Low Observables Laboratory supports graduate instruction for students enrolled in the Low Observables program. Its purpose is to introduce these...

Bifunctional Pt-Si Alloys for Small Organic Molecule Electro-oxidation

DEFF Research Database (Denmark)

Permyakova, Anastasia Aleksandrovna; Suntivich, Jin; Han, Binghong

Designing highly active catalysts for electro-oxidation of small organic molecules can help to reduce the anodic overpotential for more efficient utilization of hydrocarbon fuels. The challenge in developing more active electrocatalysts for electro-oxidation reactions is to satisfy the stringent...... adsorption site. We will discuss the enhanced activity of Pt-Si alloys for small organic molecule oxidation, which can be attributed to the improved CO electro-oxidation kinetics on Pt-Si....

Semiclassical treatment of transport and spin relaxation in spin-orbit coupled systems

Energy Technology Data Exchange (ETDEWEB)

Lueffe, Matthias Clemens

2012-02-10

The coupling of orbital motion and spin, as derived from the relativistic Dirac equation, plays an important role not only in the atomic spectra but as well in solid state physics. Spin-orbit interactions are fundamental for the young research field of semiconductor spintronics, which is inspired by the idea to use the electron's spin instead of its charge for fast and power saving information processing in the future. However, on the route towards a functional spin transistor there is still some groundwork to be done, e.g., concerning the detailed understanding of spin relaxation in semiconductors. The first part of the present thesis can be placed in this context. We have investigated the processes contributing to the relaxation of a particularly long-lived spin-density wave, which can exist in semiconductor heterostructures with Dresselhaus and Rashba spin-orbit coupling of precisely the same magnitude. We have used a semiclassical spindiffusion equation to study the influence of the Coulomb interaction on the lifetime of this persistent spin helix. We have thus established that, in the presence of perturbations that violate the special symmetry of the problem, electron-electron scattering can have an impact on the relaxation of the spin helix. The resulting temperature-dependent lifetime reproduces the experimentally observed one in a satisfactory manner. It turns out that cubic Dresselhaus spin-orbit coupling is the most important symmetry-breaking element. The Coulomb interaction affects the dynamics of the persistent spin helix also via an Hartree-Fock exchange field. As a consequence, the individual spins precess about the vector of the surrounding local spin density, thus causing a nonlinear dynamics. We have shown that, for an experimentally accessible degree of initial spin polarization, characteristic non-linear effects such as a dramatic increase of lifetime and the appearance of higher harmonics can be expected. Another fascinating solid

Enhanced electro-oxidation of ethanol using PtSn/CeO{sub 2}-C electrocatalyst prepared by an alcohol-reduction process

Energy Technology Data Exchange (ETDEWEB)

Neto, Almir Oliveira; Farias, Luciana A.; Dias, Ricardo R.; Brandalise, Michelle; Linardi, Marcelo; Spinace, Estevam V. [Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP, Av. Prof. Lineu Prestes, 2242 - Cidade Universitaria, CEP 05508-900 Sao Paulo-SP (Brazil)

2008-09-15

PtSn/CeO{sub 2}-C electrocatalysts were prepared by an alcohol-reduction process using ethylene glycol as solvent and reduction agent and CeO{sub 2} and Vulcan Carbon XC72 as supports. The electrocatalysts were characterized by EDX and XRD. The electro-oxidation of ethanol was studied at room temperature by chronoamperometry. PtSn/CeO{sub 2}-C electrocatalyst with 15 wt% of CeO{sub 2} showed a significant increase of performance for ethanol oxidation compared to PtSn/C catalyst. Preliminary tests at 100C on a single cell of a direct ethanol fuel cell (DEFC) also confirm the results obtained by chronoamperometry. (author)

Spinning of refractory metals

International Nuclear Information System (INIS)

Chang Wenkua; Zheng Han

1989-01-01

The effects of spinning process parameters including max. pass percentage reduction, spinning temperature, feed rate, lubricant and annealing technology on the quality of shaped components are summarized and discussed in the present paper. The above mentioned parameters are adopted in the process of spinning of barrel-shaped and specially shaped components of refractory metals and their alloys W, Mo, Nb, Zr, TZM molybdenum alloy, C-103, C-752 niobium alloy etc. The cause of leading to usual defects of spun products of refractory metals such as lamellar as 'scaling', crack, swelling, wrinkle, etc. have been analysed and the ways to eliminate the defects have been put forward. 8 figs., 5 tabs. (Author)

Electro-osmotic flows inside triangular microchannels

International Nuclear Information System (INIS)

Vocale, P; Spiga, M; Geri, M; Morini, G L

2014-01-01

This work presents a numerical investigation of both pure electro-osmotic and combined electro-osmotic/pressure-driven flows inside triangular microchannels. A finite element analysis has been adopted to solve the governing equations for the electric potential and the velocity field, accounting for a finite thickness of the electric double layer. The influence of non-dimensional parameters such as the aspect ratio of the cross-section, the electrokinetic diameter and the ratio of the pressure force to the electric force on the flow behavior has been investigated. Numerical results point out that the velocity field is significantly influenced by the aspect ratio of the cross section and the electrokinetic diameter. More specifically, the aspect ratio plays an important role in determining the maximum volumetric flow rate, while the electrokinetic diameter is crucial to establishing the range of pressures that may be sustained by the electro-osmotic flow. Numerical results are also compared with two correlations available in the literature which enable to assess the volumetric flow rate and the pressure head for microchannels featuring a rectangular, a trapezoidal or an elliptical cross-section.

Precision Munition Electro-Sciences Facility

Data.gov (United States)

Federal Laboratory Consortium — This facility allows the characterization of the electro-magnetic environment produced by a precision weapon in free flight. It can measure the radiofrequency (RF)...

Micro Electro Mechanical Systems: From Research to Applications

Science.gov (United States)

Lang, Walter; Sandmaier, Hermann

1998-12-01

Micro electro mechanical systems (MEMS) are in the transition phase from research to industry. This paper intends to describe this process from the point of view of a European R&D institution. The MEMS market, its development and its most important products are discussed. In the second part, the R&D activities at HSG-IMIT in Germany are described. The last chapter deals with the cooperation between the R&D institution and industry, in particular with local German small-and medium-sized enterprises.

Investigation of DBS electro-oxidation reaction in the aqueous-organic solution of LiClO{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Darlewski, Witold [Military University of Technology, Institute of Chemistry, Kaliskiego Street 2, 00-908 Warszawa (Poland); Popiel, Stanislaw, E-mail: spopiel@wat.edu.pl [Military University of Technology, Institute of Chemistry, Kaliskiego Street 2, 00-908 Warszawa (Poland); Nalepa, Tomasz [Department of Defense Affairs of the Ministry of Economy, Plac Trzech Krzyzy 3/5, 00-507 Warszawa (Poland); Gromotowicz, Waldemar [Warsaw Pharmaceutical Plant ' Polfa' S.A., Karolkowa Street 22/24, 01-207 Warszawa (Poland); Szewczyk, Rafal [Department of Biology and Environment Protection, University of Lodz, Pilarskiego Street 14/16, 90-231 Lodz (Poland); Stankiewicz, Romuald [Warsaw University, Department of Physics, Hoza Street 69, 00-681 Warszawa (Poland)

2010-03-15

A process of dibutyl sulphide (DBS) electro-oxidation using electrolysis and cyclic voltamperometry was investigated in water-methanol solution using different electrodes (platinum, boron doped diamond, graphite and glassy carbon). Obtained results indicate that the DBS electro-oxidation process is irreversible in voltamperometric conditions. It was shown that during DBS electrolytic oxidation on Pt, at the low anode potential (1.8 V), DBS was oxidized to sulphoxide and sulphone. Electrolysis at higher potential (up to 3.0 V) resulted in complete DBS oxidation and formation of various products, including: butyric acid, sulphuric acid, butanesulphinic acid, butanesulphonic acid, identified using gas chromatography (GC-AED) and mass spectrometry (GC-MS) methods.

Paramagnetic material for quantum information processing: electronic and nuclear spins manipulations in β - Ga2O3: Ti

International Nuclear Information System (INIS)

Mentink-Vigier, Frederic

2011-01-01

Quantum information processing is a major challenge both on fundamental and technological grounds. In this research field, the spin bus concept relies on the use of both the electronic and nuclear spins in which the electron is used as a reading and writing head over the nuclei system which makes the qubit register. The requested material to build a spin bus must have unpaired electrons delocalized over a great number of nuclear spins having long decoherence time. In this work, we studied a spin system composed of titanium (III) interacting with multiple gallium nuclei in gallium oxide. We synthesized and studied the titanium paramagnetic center in gallium oxide single crystals by continuous wave EPR and ENDOR spectroscopy and showed that the electron is delocalized over eight neighbouring gallium nuclei. This study also revealed a strong isotopic effect on the nucleus-nucleus interaction mediated by the electron. When the two nearest gallium nuclei surrounding the titanium are identical (same isotopes) this interaction is one order of magnitude higher than in the case of inequivalent nuclei. This effect can be used in order to reduce the computation time. Finally, the dynamical properties of the spin system have been characterized by pulsed EPR and ENDOR spectroscopy. The electron spin decoherence is driven by instantaneous and spectral diffusion. The nuclear dynamical properties have also been studied in order to determine the order of magnitude of nuclear spin relaxation and decoherence time. (author) [fr

Spin transport in epitaxial graphene

Science.gov (United States)

Tbd, -

2014-03-01

Spintronics is a paradigm focusing on spin as the information vector in fast and ultra-low-power non volatile devices such as the new STT-MRAM. Beyond its widely distributed application in data storage it aims at providing more complex architectures and a powerful beyond CMOS solution for information processing. The recent discovery of graphene has opened novel exciting opportunities in terms of functionalities and performances for spintronics devices. We will present experimental results allowing us to assess the potential of graphene for spintronics. We will show that unprecedented highly efficient spin information transport can occur in epitaxial graphene leading to large spin signals and macroscopic spin diffusion lengths (~ 100 microns), a key enabler for the advent of envisioned beyond-CMOS spin-based logic architectures. We will also show that how the device behavior is well explained within the framework of the Valet-Fert drift-diffusion equations. Furthermore, we will show that a thin graphene passivation layer can prevent the oxidation of a ferromagnet, enabling its use in novel humide/ambient low-cost processes for spintronics devices, while keeping its highly surface sensitive spin current polarizer/analyzer behavior and adding new enhanced spin filtering property. These different experiments unveil promising uses of graphene for spintronics.

Factors impacting the electro conductivity variations of clayey soils

International Nuclear Information System (INIS)

Ouhadi, V. R.; Goodarzi, A. R.

2007-01-01

The variation of pore fluid properties in soil has a major effect on soil behaviour. This effect is a function of pore fluid properties and soil mineralogy. Such variation usually happens in the reservoirs of dams or in some geotechnical projects. The electro conductivity measurement is a simple method to monitor any variation in the pore fluid of soils. electro conductivity is the ability of a material to transmit (conduct) an electrical current. This paper focuses attention on the effect of soil-pore fluid interaction on the electro conductivity of clayey soils. A set of physico-chemical experiments are performed and the role of different factors including soil pH, soil mineralogy, soil: water ratio, cation and anion effects are investigated. The results of this study indicate that for soil that has a relatively low CEC, the anion type is an important factor, while the cation type does not noticeably affect the electro conductivity of the soil-solution. However, for such soil, an electrolyte property, i.e. its solubility, is much more effective than the CEC of the soil. In addition, it was observed that in the presence of neutral salts such as pore fluid, the pH of the soil-solution decreases causing an increase in the electro conductivity of the soil sample

The non-linear coupled spin 2-spin 3 Cotton equation in three dimensions

Energy Technology Data Exchange (ETDEWEB)

Linander, Hampus; Nilsson, Bengt E.W. [Department of Physics, Theoretical PhysicsChalmers University of Technology, S-412 96 Göteborg (Sweden)

2016-07-05

In the context of three-dimensional conformal higher spin theory we derive, in the frame field formulation, the full non-linear spin 3 Cotton equation coupled to spin 2. This is done by solving the corresponding Chern-Simons gauge theory system of equations, that is, using F=0 to eliminate all auxiliary fields and thus expressing the Cotton equation in terms of just the spin 3 frame field and spin 2 covariant derivatives and tensors (Schouten). In this derivation we neglect the spin 4 and higher spin sectors and approximate the star product commutator by a Poisson bracket. The resulting spin 3 Cotton equation is complicated but can be related to linearized versions in the metric formulation obtained previously by other authors. The expected symmetry (spin 3 “translation”, “Lorentz” and “dilatation”) properties are verified for Cotton and other relevant tensors but some perhaps unexpected features emerge in the process, in particular in relation to the non-linear equations. We discuss the structure of this non-linear spin 3 Cotton equation but its explicit form is only presented here, in an exact but not completely refined version, in appended files obtained by computer algebra methods. Both the frame field and metric formulations are provided.

Manipulating spin in organic spintronics : probing the interplay between the electronic and nuclear spins in organic semiconductors

NARCIS (Netherlands)

Bobbert, P.A.

2014-01-01

The growing interest in spin manipulation in the field of spin electronics, or "spintronics," is due to the wealth of exciting possibilities that it offers in areas of magnetic sensing, new types of information storage, low-power electronics, and quantum information processing. Nuclear spin

Geometrical spin symmetry and spin

International Nuclear Information System (INIS)

Pestov, I. B.

2011-01-01

Unification of General Theory of Relativity and Quantum Mechanics leads to General Quantum Mechanics which includes into itself spindynamics as a theory of spin phenomena. The key concepts of spindynamics are geometrical spin symmetry and the spin field (space of defining representation of spin symmetry). The essence of spin is the bipolar structure of geometrical spin symmetry induced by the gravitational potential. The bipolar structure provides a natural derivation of the equations of spindynamics. Spindynamics involves all phenomena connected with spin and provides new understanding of the strong interaction.

Electro-spark deposition technology

Energy Technology Data Exchange (ETDEWEB)

Johnson, R.N. [Pacific Northwest National Lab., Richland, WA (United States)

1997-12-01

Electro-Spark Deposition (ESD) is a micro-welding process that uses short duration, high-current electrical pulses to deposit or alloy a consumable electrode material onto a metallic substrate. The ESD process was developed to produce coatings for use in severe environments where most other coatings fail. Because of the exceptional damage resistance of these coatings, and the versatility of the process to apply a wide variety of alloys, intermetallics, and cermets to metal surfaces, the ESD process has been designated critical to the life and economy of the advanced fossil energy systems as the higher temperatures and corrosive environments exceed the limits of known structural materials to accommodate the service conditions. Developments include producing iron aluminide-based coatings with triple the corrosion resistance of the best previous Fe{sub 3}Al coatings, coatings with refractory metal diffusion barriers and multi layer coatings for achieving functionally gradient properties between the substrate and the surface. A new development is the demonstration of advanced aluminide-based ESD coatings for erosion and wear applications. One of the most significant breakthroughs to occur in the last dozen years is the discovery of a process regime that yields an order of magnitude increase in deposition rates and achievable coating thicknesses. Achieving this regime has required the development of advanced ESD electronic capabilities. Development is now focused on further improvements in deposition rates, system reliability when operating at process extremes, and economic competitiveness.

Properties of asymmetry of the electro disintegration process with vector-polarized deuterons

CERN Document Server

Rekalo, M P; Rekalo, O P

2002-01-01

The properties of the asymmetry A sub y (theta) in the exclusive electro disintegration of vector-polarized deuteron d-vector (e, e' p)n have been investigated (the vector of the target polarization is directed perpendicularly to the plane of the reaction gamma sup * + d-vector -> n + p). All calculations have been done in the framework of relativistic impulse approximation with the unitarized multipole gamma sup * + d-vector -> n + p amplitudes in order to account the final-state NN interaction in the reaction d-vector (e, e' p)n. The significance of various mechanisms in the formation of the angular dependence of the asymmetry A sub y (theta) has been discussed for the complanar kinematical conditions.

A New Servo Control Drive for Electro Discharge Texturing System Industrial Applications Using Ultrasonic Technology

Directory of Open Access Journals (Sweden)

M. Shafik

2013-07-01

Full Text Available This paper presents a new ultrasonic servo control drive for electro discharge texturing system industrial applications. The new drive is aiming to overcome the current teething issues of the existing electro discharge texturing system, servo control drive level of precision, processing stability, dynamic response and surface profile of the machined products. The new ultrasonic servo control drive consists of three main apparatuses, an ultrasonic motor, electronic driver and control unit. The ultrasonic motor consists of three main parts, the stator, rotor and sliding element. The motor design process, basic configuration, principles of motion, finite element analysis and experimental examination of the main characteristics is discussed in this paper. The electronic driver of the motor consists of two main stages which are the booster and piezoelectric amplifier. The experimental test and validation of the developed servo control drive in electro discharge texturing platform is also discussed and presented in this paper. The initial results showed that the ultrasonic servo control drive is able to provide: a bidirectional of motion, a resolution of <50μm and a dynamic response of <10msec. The electron microscopic micro examination into the textured samples showed that: a clear improvement in machining stability, products surface profile, a notable reduction in the processing time, arcing and short-circuiting teething phenomena.

Sequential pretreatment for cell disintegration of municipal sludge in a neutral Bio-electro-Fenton system.

Science.gov (United States)

Yu, Qilin; Jin, Xiaochen; Zhang, Yaobin

2018-05-15

Sludge cell disruption was generally considered as the rate-limiting step for the anaerobic digestion of waste activated sludge (WAS). Advanced oxidation processes and bio-electro-chemical systems were recently reported to enhance the hydrolysis of WAS and sludge cell disruption, while the cell-breaking processes of these systems remain unclear yet. In this study, an innovative Bio-electro-Fenton system was developed to pretreat the WAS sequentially with cathode Fenton process and anode anaerobic digestion. Significant cell disruption and dissolution intracellular organics were founded after the treatment. X-ray photoelectron spectroscopy (XPS) analysis and fourier transform infrared spectroscopy (FT-IR) spectra indicated that Gram-negative bacteria were more sensitive to free radicals yielded in cathode to induce a chain reaction that destroyed the lipid-contained outer membrane, while Gram-positive bacteria with thick peptidoglycan layer were liable to be biologically decomposed in the anode. Compared with the oxidation of organic matters in the cathode Fenton, the secretion of enzyme increased in the anode which was beneficial to break down the complex matters (peptidoglycans) into simples that were available for anode oxidation by exoelectrogens. The results also showed a possible prospect for the application of this sequential pretreatment in bio-electro-Fenton systems to disrupt sludge cells and enhance the anaerobic digestion. Copyright © 2018 Elsevier Ltd. All rights reserved.

Preparation and Characterization of Soluble Eggshell Membrane Protein/PLGA Electro spun Nano fibers for Guided Tissue Regeneration Membrane

International Nuclear Information System (INIS)

Jia, J.; Liu, G.; Duan, Y.; Guo, Z.; Yu, J.

2012-01-01

Guided tissue regeneration (GTR) is a widely used method in periodontal therapy, which involves the placement of a barrier membrane to exclude migration of epithelium and ensure repopulation of periodontal ligament cells. The objective of this study is to prepare and evaluate a new type of soluble eggshell membrane protein (SEP)/poly (lactic-co-glycolic acid) (PLGA) nano fibers using electro spinning method for GTR membrane application. SEP/PLGA nano fibers were successfully prepared with various blending ratios. The morphology, chemical composition, surface wettability, and mechanical properties of the nano fibers were characterized using scanning electron microscopy (SEM), contact angle measurement, Fourier transform-infrared spectroscopy (FTIR), and a universal testing machine. L-929 fibroblast cells were used to evaluate the biocompatibility of SEP/PLGA nano fibers and investigate the interaction between cells and nano fibers. Results showed that the SEP/PLGA electro spun membrane was composed of uniform, bead-free nano fibers, which formed an interconnected porous network structure. Mechanical property of SEP has been greatly improved by the addition of PLGA. The biological study results showed that SEP/PLGA nano fibers could enhance cell attachment, spreading, and proliferation. The study indicated the potential of SEP/PLGA nano fibers for GTR application and provided a basis for future optimization

Classical spins in superconductors

Energy Technology Data Exchange (ETDEWEB)

Shiba, H [Tokyo Univ.; Maki, K

1968-08-01

It is shown that there exists a localized excited state in the energy gap in a superconductor with a classical spin. At finite concentration localized excited states around classical spins form an impurity band. The process of growth of the impurity band and its effects on observable quantities are investigated.

Spin Torques in Systems with Spin Filtering and Spin Orbit Interaction

KAUST Repository

Ortiz Pauyac, Christian

2016-06-19

In the present thesis we introduce the reader to the field of spintronics and explore new phenomena, such as spin transfer torques, spin filtering, and three types of spin-orbit torques, Rashba, spin Hall, and spin swapping, which have emerged very recently and are promising candidates for a new generation of memory devices in computer technology. A general overview of these phenomena is presented in Chap. 1. In Chap. 2 we study spin transfer torques in tunnel junctions in the presence of spin filtering. In Chap. 3 we discuss the Rashba torque in ferromagnetic films, and in Chap. 4 we study spin Hall effect and spin swapping in ferromagnetic films, exploring the nature of spin-orbit torques based on these mechanisms. Conclusions and perspectives are summarized in Chap. 5.

Electro-oxidation of the dye azure B: kinetics, mechanism, and by-products.

Science.gov (United States)

Olvera-Vargas, Hugo; Oturan, Nihal; Aravindakumar, C T; Paul, M M Sunil; Sharma, Virender K; Oturan, Mehmet A

2014-01-01

In this work, the electrochemical degradation of the dye azure B in aqueous solutions was studied by electrochemical advanced oxidation processes (EAOPs), electro-Fenton, and anodic oxidation processes, using Pt/carbon-felt and boron-doped diamond (BDD)/carbon-felt cells with H₂O₂ electrogeneration. The higher oxidation power of the electro-Fenton (EF) process using BDD anode was demonstrated. The oxidative degradation of azure B by the electrochemically generated hydroxyl radicals ((•)OH) follows a pseudo-first-order kinetics. The apparent rate constants of the oxidation of azure B by (•)OH were measured according to pseudo-first-order kinetic model. The absolute rate constant of azure B hydroxylation reaction was determined by competition kinetics method and found to be 1.19 × 10(9) M(-1) s(-1). It was found that the electrochemical degradation of the dye leads to the formation of aromatic by-products which are then oxidized to aliphatic carboxylic acids before their almost mineralization to CO₂ and inorganic ions (sulfate, nitrate, and ammonium). The evolution of the TOC removal and time course of short-chain carboxylic acids during treatment were also investigated.

Electro-optical frequency shifting of lasers for plasma diagnostics

International Nuclear Information System (INIS)

Forman, P.R.

1977-07-01

An electro-optical frequency shifting device is proposed as an aid for plasma physics heterodyne interferometry and heterodyne scattering experiments. The method has the advantage over other electro-optic shifters, that a pure separable frequency shifted beam can be obtained even when less than half wave voltage is applied. (orig.) [de

Muonium spin exchange as a Poisson process: magnetic field dependence in transverse fields

International Nuclear Information System (INIS)

Senba, Masayoshi; British Columbia Univ., Vancouver, BC

1993-01-01

The muonium spin exchange has been investigated as a function of transverse magnetic field strength, where the Poisson nature of collisions is exploited to simplify the calculation. In intermediate fields where the so-called two-frequency muonium signal is observed, the muonium relaxation due to spin exchange is 1.5 times faster than in low fields. In even higher fields, the observed relaxation rate drops back to the low field value. Since the relaxation rate due to a chemical reaction is field independent, such a distinct field dependence in spin exchange can be used in distinguishing experimentally spin exchange from chemical reactions. The time evolution of the muon spin polarization in the presence of muonium spin exchange has been expressed in a simple analytical closed form. (author)

High performance electro-optical modulator based on photonic crystal and graphene

Science.gov (United States)

Malekmohammad, M.; Asadi, R.

2017-07-01

An electro-optical modulator is demonstrated based on Fano-resonance effect in an out-of-plane illumination of one-dimensional slab photonic crystal composed of two graphene layers. It has been shown that high sensitivity of the Fano-resonance and electro-refractive tuning of graphene layers provides a suitable condition to obtain an electro-optical modulator with low energy consumption (8 pJ) with contrast of 0.4.

Electro-optical hybrid slip ring

Science.gov (United States)

Hong, En

2005-11-01

The slip ring is a rotary electrical interface, collector, swivel or rotary joint. It is a physical system that can perform continuous data transfer and data exchange between a stationary and a rotating structure. A slip ring is generally used to transfer data or power from an unrestrained, continuously rotating electro-mechanical system in real-time, thereby simplifying operations and eliminating damage-prone wires dangling from moving joints. Slip rings are widely used for testing, evaluating, developing and improving various technical equipment and facilities with rotating parts. They are widely used in industry, especially in manufacturing industries employing turbo machinery, as in aviation, shipbuilding, aerospace, defense, and in precise facilities having rotating parts such as medical Computerized Tomography (CT) and MRI scanners and so forth. Therefore, any improvement in slip ring technology can impact large markets. Research and development in this field will have broad prospects long into the future. The goal in developing the current slip ring technology is to improve and increase the reliability, stability, anti-interference, and high data fidelity between rotating and stationary structures. Up to now, there have been numerous approaches used for signal and data transfer utilizing a slip ring such as metal contacts, wires, radio transmission, and even liquid media. However, all suffer from drawbacks such as data transfer speed limitations, reliability, stability, electro-magnetic interference and durability. The purpose of the current research is to break through these basic limitations using an optical solution, thereby improving performance in current slip ring applications. This dissertation introduces a novel Electro-Optical Hybrid Slip Ring technology, which makes "through the air" digital-optical communication between stationary and rotating systems a reality with high data transfer speed, better reliability and low interference susceptibility

Surface effects on anti-plane shear waves propagating in magneto-electro-elastic nanoplates

International Nuclear Information System (INIS)

Wu, Bin; Zhang, Chunli; Chen, Weiqiu; Zhang, Chuanzeng

2015-01-01

Material surfaces may have a remarkable effect on the mechanical behavior of magneto-electro-elastic (or multiferroic) structures at nanoscale. In this paper, a surface magneto-electro-elasticity theory (or effective boundary condition formulation), which governs the motion of the material surface of magneto-electro-elastic nanoplates, is established by employing the state-space formalism. The properties of anti-plane shear (SH) waves propagating in a transversely isotropic magneto-electro-elastic plate with nanothickness are investigated by taking surface effects into account. The size-dependent dispersion relations of both antisymmetric and symmetric SH waves are presented. The thickness-shear frequencies and the asymptotic characteristics of the dispersion relations considering surface effects are determined analytically as well. Numerical results show that surface effects play a very pronounced role in elastic wave propagation in magneto-electro-elastic nanoplates, and the dispersion properties depend strongly on the chosen surface material parameters of magneto-electro-elastic nanoplates. As a consequence, it is possible to modulate the waves in magneto-electro-elastic nanoplates through surface engineering. (paper)

The transverse shear deformation behaviour of magneto-electro-elastic shell

International Nuclear Information System (INIS)

Albarody, Thar M. Badri; Al-Kayiem, Hussain H.; Faris, Waleed

2016-01-01

Compared to the large number of possible magneto-electro-elastic shell theories, very few exact solutions determining the in-plane stresses, electric displacements and magnetic inductions are possible. While, solving the magneto-electro-elastic shell equations in terms of thermo-magneto-electro-elastic generalized field functions on arbitrary domains and for general conditions exactly are not always possible. In the present work, a linear version of magneto-electro-elastic shell with simply supported boundary conditions, solved exactly, provided that the lamination scheme is cross-ply or anti-symmetric angle-ply laminates. The exact solution that introduced herein can measure the in-plane stresses, electric displacements and magnetic inductions. It also allow for an accurate and usually elegant and conclusive investigation of the various sensations in a shell structure. However, it is important for micro-electro-mechanical shell applications to have an approach available that gives the transverse shear deformation Behaviour for cases that cannot examine experimentally. An investigated examples were accompanied and noteworthy conclusions were drawn which highlight the issues of the implementation of the exact solution, implication of the effects of the material properties, lay-ups of the constituent layers, and shell parameters on the static Behaviour

The transverse shear deformation behaviour of magneto-electro-elastic shell

Energy Technology Data Exchange (ETDEWEB)

Albarody, Thar M. Badri; Al-Kayiem, Hussain H. [UniversitiTeknologi PETRONAS, Perak (Malaysia); Faris, Waleed [International Islamic University Malaysia, Perak (Malaysia)

2016-01-15

Compared to the large number of possible magneto-electro-elastic shell theories, very few exact solutions determining the in-plane stresses, electric displacements and magnetic inductions are possible. While, solving the magneto-electro-elastic shell equations in terms of thermo-magneto-electro-elastic generalized field functions on arbitrary domains and for general conditions exactly are not always possible. In the present work, a linear version of magneto-electro-elastic shell with simply supported boundary conditions, solved exactly, provided that the lamination scheme is cross-ply or anti-symmetric angle-ply laminates. The exact solution that introduced herein can measure the in-plane stresses, electric displacements and magnetic inductions. It also allow for an accurate and usually elegant and conclusive investigation of the various sensations in a shell structure. However, it is important for micro-electro-mechanical shell applications to have an approach available that gives the transverse shear deformation Behaviour for cases that cannot examine experimentally. An investigated examples were accompanied and noteworthy conclusions were drawn which highlight the issues of the implementation of the exact solution, implication of the effects of the material properties, lay-ups of the constituent layers, and shell parameters on the static Behaviour.

The finite element simulation analysis research of 38CrSi cylindrical power spinning

Science.gov (United States)

Liang, Wei; Lv, Qiongying; Zhao, Yujuan; Lv, Yunxia

2018-01-01

In order to grope for the influence of the main cylindrical spinning process parameters on the spinning process, this paper combines with real tube power spinning process and uses ABAQUS finite element analysis software to simulate the tube power spinning process of 38CrSi steel materials, through the analysis of the stress, strain of the part forming process, analyzes the influence of the thickness reduction and the feed rate to the forming process, and analyzes the variation of the spinning force, finally determines the reasonable main spinning process parameters combination.

Increasing the number of spin-outs from Danish universities

DEFF Research Database (Denmark)

Andersen, Lars-Ulrik Aaen

2011-01-01

In this paper I describe some of the barriers and motivations involved in the process of creating spin-out companies from Danish universities – based on a study carried out at the Technical University of Denmark (DTU). Even if procedures are established to support the spin-out process...... in the spin-out process the study reveals some of the barriers of the employees at the universities but also the other stakeholders view on the process. The investigation also reveals the various motivations for starting up a spin-out company and input to what the university/department can do to facilitate......, there are still barriers that hinder the process. In this paper I investigate these barriers and the possible motivations that could increase the number of spin-outs. I also discuss some of the processes and tools that could be implemented to support the process. Based on interviews with a number of stakeholders...

Electro-optical rendezvous and docking sensors

Science.gov (United States)

Tubbs, David J.; Kesler, Lynn O.; Sirko, Robert J.

1991-01-01

Electro-optical sensors provide unique and critical functionality for space missions requiring rendezvous, docking, and berthing. McDonnell Douglas is developing a complete rendezvous and docking system for both manned and unmanned missions. This paper examines our sensor development and the systems and missions which benefit from rendezvous and docking sensors. Simulation results quantifying system performance improvements in key areas are given, with associated sensor performance requirements. A brief review of NASA-funded development activities and the current performance of electro-optical sensors for space applications is given. We will also describe current activities at McDonnell Douglas for a fully functional demonstration to address specific NASA mission needs.

Laser resolution of unpolarized-electron scattering cross sections into spin-conserved and spin-flip components

International Nuclear Information System (INIS)

Ritchie, B.

1981-01-01

The theory is presented for one-photon free-free absorption by electrons scattering from high-Z atoms. The absorption cross section provides sufficient information to resolve the unpolarized-electron total cross section, Vertical Barf(theta)Vertical Bar 2 +Vertical Barg(theta)Vertical Bar 2 , into its individual components for spin-nonflip, Vertical Barf(theta)Vertical Bar 2 , and spin-flip, Vertical Barg(theta)Vertical Bar 2 , scattering. The observation of a spin-polarization effect for a spin-independent process (free-free absorption) is analogous to the Fano effect for bound-free absorption

Skyrmion creation and annihilation by spin waves

International Nuclear Information System (INIS)

Liu, Yizhou; Yin, Gen; Lake, Roger K.; Zang, Jiadong; Shi, Jing

2015-01-01

Single skyrmion creation and annihilation by spin waves in a crossbar geometry are theoretically analyzed. A critical spin-wave frequency is required both for the creation and the annihilation of a skyrmion. The minimum frequencies for creation and annihilation are similar, but the optimum frequency for creation is below the critical frequency for skyrmion annihilation. If a skyrmion already exists in the cross bar region, a spin wave below the critical frequency causes the skyrmion to circulate within the central region. A heat assisted creation process reduces the spin-wave frequency and amplitude required for creating a skyrmion. The effective field resulting from the Dzyaloshinskii-Moriya interaction and the emergent field of the skyrmion acting on the spin wave drive the creation and annihilation processes

Ultra-thin film encapsulation processes for micro-electro-mechanical devices and systems

International Nuclear Information System (INIS)

Stoldt, Conrad R; Bright, Victor M

2006-01-01

A range of physical properties can be achieved in micro-electro-mechanical systems (MEMS) through their encapsulation with solid-state, ultra-thin coatings. This paper reviews the application of single source chemical vapour deposition and atomic layer deposition (ALD) in the growth of submicron films on polycrystalline silicon microstructures for the improvement of microscale reliability and performance. In particular, microstructure encapsulation with silicon carbide, tungsten, alumina and alumina-zinc oxide alloy ultra-thin films is highlighted, and the mechanical, electrical, tribological and chemical impact of these overlayers is detailed. The potential use of solid-state, ultra-thin coatings in commercial microsystems is explored using radio frequency MEMS as a case study for the ALD alloy alumina-zinc oxide thin film. (topical review)

Kinetics of Carbon Monoxide Electro-Oxidation in Solid-Oxide Fuel Cells from Ni-YSZ Patterned-Anode Measurements

KAUST Repository

Hanna, J.; Lee, W. Y.; Ghoniem, A. F.

2013-01-01

A mathematical model is developed around the framework of a reduced mechanism describing electrochemical oxidation of carbon monoxide on Ni-YSZ patterned anodes. The electro-oxidation mechanism involves three reactions, one describing adsorption/ desorption of COonNi, and two single-electron charge-transfer steps inwhich the surface adsorbate CO(Ni) participates directly. These steps are coupled with surface transport in a reaction-diffusion model for which analytic equilibrium and steady-state solutions are derived. As much as possible, we make use of existing, independent, published information about heterogeneous chemistry, surface transport, and other model parameters. The only unknowns in our model are taken to be the kinetic rate constants of the electrochemical reactions, which we evaluate by fitting the model predictions to previously published patterned-anode experiments [B. Habibzadeh, Ph.D. Thesis, University of Maryland, College Park, MD, USA (2007)]. The results show that diffusion of CO on the Ni surface to the three-phase boundary is the rate-controlling process for CO electro-oxidation. Moreover, from a reaction standpoint, the charge-transfer process is dominated by a slow step involving CO(Ni). These findings collectively demonstrate the critical dependence of the electro-oxidation process to the direct participation of CO. © 2013 The Electrochemical Society. All rights reserved.

Kinetics of Carbon Monoxide Electro-Oxidation in Solid-Oxide Fuel Cells from Ni-YSZ Patterned-Anode Measurements

KAUST Repository

Hanna, J.

2013-04-17

A mathematical model is developed around the framework of a reduced mechanism describing electrochemical oxidation of carbon monoxide on Ni-YSZ patterned anodes. The electro-oxidation mechanism involves three reactions, one describing adsorption/ desorption of COonNi, and two single-electron charge-transfer steps inwhich the surface adsorbate CO(Ni) participates directly. These steps are coupled with surface transport in a reaction-diffusion model for which analytic equilibrium and steady-state solutions are derived. As much as possible, we make use of existing, independent, published information about heterogeneous chemistry, surface transport, and other model parameters. The only unknowns in our model are taken to be the kinetic rate constants of the electrochemical reactions, which we evaluate by fitting the model predictions to previously published patterned-anode experiments [B. Habibzadeh, Ph.D. Thesis, University of Maryland, College Park, MD, USA (2007)]. The results show that diffusion of CO on the Ni surface to the three-phase boundary is the rate-controlling process for CO electro-oxidation. Moreover, from a reaction standpoint, the charge-transfer process is dominated by a slow step involving CO(Ni). These findings collectively demonstrate the critical dependence of the electro-oxidation process to the direct participation of CO. © 2013 The Electrochemical Society. All rights reserved.

The electron-spin--nuclear-spin interaction studied by polarized neutron scattering.

Science.gov (United States)

Stuhrmann, Heinrich B

2007-11-01

Dynamic nuclear spin polarization (DNP) is mediated by the dipolar interaction of paramagnetic centres with nuclear spins. This process is most likely to occur near paramagnetic centres at an angle close to 45 degrees with respect to the direction of the external magnetic field. The resulting distribution of polarized nuclear spins leads to an anisotropy of the polarized neutron scattering pattern, even with randomly oriented radical molecules. The corresponding cross section of polarized coherent neutron scattering in terms of a multipole expansion is derived for radical molecules in solution. An application using data of time-resolved polarized neutron scattering from an organic chromium(V) molecule is tested.

Electrochemical treatment of Acid Red 1 by electro-Fenton and photoelectro-Fenton processes

Directory of Open Access Journals (Sweden)

Camilo González-Vargas

2014-12-01

Full Text Available Small volumes (100 mL of acidic aqueous solutions with 30-200 mg L-1 TOC of the toxic azo dye Acid Red 1 (AR1 have been comparatively treated by various electrochemical advanced oxidation processes (EAOPs. The electrolytic system consisted of a BDD anode able to produce ·OH and an air-diffusion cathode that generated H2O2, which subsequently reacted with added Fe2+ to yield additional ·OH from Fenton’s reaction. Under optimized conditions (i.e., 1.0 mM Fe2+, 60 mA cm-2, pH 3.0, 35 ºC, the analysis of the initial rates for decolourization and AR1 decay assuming a pseudo-first-order kinetics revealed a much higher rate constant for photoelectro-Fenton (PEF, ~ 2.7x10-3 s-1 compared to electro-Fenton (EF, ~ 0.6x10-3 s-1. Mineralization after 180 min was also greater in the former treatment (90 % vs 63 %. The use of UV radiation in PEF contributed to Fe(III photoreduction as well as to photodecarboxylation of refractory intermediates, yielding a mineralization current efficiency as high as 85% during the treatment of solutions of 200 mg L-1 TOC. Primary reaction intermediates included three aromatic derivatives with the initial naphthalenic structure and four molecules only featuring benzenic rings, which were totally mineralized in PEF. 

An analysis of electro-osmotic and magnetohydrodynamic heat pipes

International Nuclear Information System (INIS)

Harrison, M.A.

1988-01-01

Mechanically simple methods of improving heat transport in heat pipes are investigated. These methods are electro-osmotic and magnetohydrodynamic augmentation. For the electro-osmotic case, a detailed electrokinetic model is used. The electrokinetic model used includes the effects of pore surface curvature and multiple ion diffusivities. The electrokinetic model is extended to approximate the effects of elevated temperature. When the electro-osmotic model is combined with a suitable heat-pipe model, it is found that the electro-osmotic pump should be a thin membrane. Arguments are provided that support the use of a volatile electrolyte. For the magnetohydrodynamic case, a brief investigation is provided. A quasi-one-dimensional hydromagnetic duct flow model is used. This hydromagnetic model is extended to approximate flow effects unique to heat pipes. When combined with a suitable heat pipe model, it is found that there is no performance gain for the case considered. In fact, there are serious pressure-distribution problems that have not been previously recognized. Potential solutions to these pressure-distribution problems are suggested

Spin current and spin transfer torque in ferromagnet/superconductor spin valves

Science.gov (United States)

Moen, Evan; Valls, Oriol T.

2018-05-01

Using fully self-consistent methods, we study spin transport in fabricable spin valve systems consisting of two magnetic layers, a superconducting layer, and a spacer normal layer between the ferromagnets. Our methods ensure that the proper relations between spin current gradients and spin transfer torques are satisfied. We present results as a function of geometrical parameters, interfacial barrier values, misalignment angle between the ferromagnets, and bias voltage. Our main results are for the spin current and spin accumulation as functions of position within the spin valve structure. We see precession of the spin current about the exchange fields within the ferromagnets, and penetration of the spin current into the superconductor for biases greater than the critical bias, defined in the text. The spin accumulation exhibits oscillating behavior in the normal metal, with a strong dependence on the physical parameters both as to the structure and formation of the peaks. We also study the bias dependence of the spatially averaged spin transfer torque and spin accumulation. We examine the critical-bias effect of these quantities, and their dependence on the physical parameters. Our results are predictive of the outcome of future experiments, as they take into account imperfect interfaces and a realistic geometry.

Quantum model for electro-optical amplitude modulation.

Science.gov (United States)

Capmany, José; Fernández-Pousa, Carlos R

2010-11-22

We present a quantum model for electro-optic amplitude modulation, which is built upon quantum models of the main photonic components that constitute the modulator, that is, the guided-wave beamsplitter and the electro-optic phase modulator and accounts for all the different available modulator structures. General models are developed both for single and dual drive configurations and specific results are obtained for the most common configurations currently employed. Finally, the operation with two-photon input for the control of phase-modulated photons and the important topic of multicarrier modulation are also addressed.

Spin relaxation rates in quantum dots: Role of the phonon modulated spin orbit interaction

Science.gov (United States)

Alcalde, A. M.; Romano, C. L.; Marques, G. E.

2008-11-01

We calculate the spin relaxation rates in InAs and GaAs parabolic quantum dots due to the interaction of spin carriers with acoustical phonons. We consider a spin relaxation mechanism completely intrinsic to the system, since it is based on the modulation of the spin-orbit interaction by the acoustic phonon potential, which is independent of any structural properties of the confinement potential. The electron-phonon deformation potential and the piezoelectric interaction are described by the Pavlov-Firsov spin-phonon Hamiltonian. Our results demonstrate that, for narrow-gap semiconductors, the deformation potential interaction becomes dominant. This behavior is not observed for wide or intermediate gap semiconductors, where the piezoelectric coupling, in general, governs the relaxation processes. We also demonstrate that the spin relaxation rates are particularly sensitive to values of the Landé g-factor, which depend strongly on the spatial shape of the confinement.

Valley- and spin-switch effects in molybdenum disulfide superconducting spin valve

Science.gov (United States)

Majidi, Leyla; Asgari, Reza

2014-10-01

We propose a hole-doped molybdenum disulfide (MoS2) superconducting spin valve (F/S/F) hybrid structure in which the Andreev reflection process is suppressed for all incoming waves with a determined range of the chemical potential in ferromagnetic (F) region and the cross-conductance in the right F region depends crucially on the configuration of magnetizations in the two F regions. Using the scattering formalism, we find that the transport is mediated purely by elastic electron cotunneling (CT) process in a parallel configuration and changes to the pure crossed Andreev reflection (CAR) process in the low-energy regime, without fixing of a unique parameter, by reversing the direction of magnetization in the right F region. This suggests both valley- and spin-switch effects between the perfect elastic CT and perfect CAR processes and makes the nonlocal charge current to be fully valley- and spin-polarized inside the right F region where the type of the polarizations can be changed by reversing the magnetization direction in the right F region. We further demonstrate that the presence of the strong spin-orbit interaction λ and an additional topological term (β ) in the Hamiltonian of MoS2 result in an enhancement of the charge conductance of the CT and CAR processes and make them to be present for long lengths of the superconducting region. Besides, we find that the thermal conductance of the structure with a small length of the highly doped superconducting region exhibits linear dependence on the temperature at low temperatures, whereas it enhances exponentially at higher temperatures. In particular, we demonstrate that the thermal conductance versus the strength of the exchange field (h ) in F region displays a maximum value at h <λ , which moves towards larger exchange fields by increasing the temperature.

Electro-Conductive Membranes for Permeation Enhancement and Fouling Mitigation: A Short Review

Directory of Open Access Journals (Sweden)

Patrizia Formoso

2017-07-01

Full Text Available The research on electro-conductive membranes has expanded in recent years. These membranes have strong prospective as key components in next generation water treatment plants because they are engineered in order to enhance their performance in terms of separation, flux, fouling potential, and permselectivity. The present review summarizes recent developments in the preparation of electro-conductive membranes and the mechanisms of their response to external electric voltages in order to obtain an improvement in permeation and mitigation in the fouling growth. In particular, this paper deals with the properties of electro-conductive polymers and the preparation of electro-conductive polymer membranes with a focus on responsive membranes based on polyaniline, polypyrrole and carbon nanotubes. Then, some examples of electro-conductive membranes for permeation enhancement and fouling mitigation by electrostatic repulsion, hydrogen peroxide generation and electrochemical oxidation will be presented.

Electro-Conductive Membranes for Permeation Enhancement and Fouling Mitigation: A Short Review.

Science.gov (United States)

Formoso, Patrizia; Pantuso, Elvira; De Filpo, Giovanni; Nicoletta, Fiore Pasquale

2017-07-28

The research on electro-conductive membranes has expanded in recent years. These membranes have strong prospective as key components in next generation water treatment plants because they are engineered in order to enhance their performance in terms of separation, flux, fouling potential, and permselectivity. The present review summarizes recent developments in the preparation of electro-conductive membranes and the mechanisms of their response to external electric voltages in order to obtain an improvement in permeation and mitigation in the fouling growth. In particular, this paper deals with the properties of electro-conductive polymers and the preparation of electro-conductive polymer membranes with a focus on responsive membranes based on polyaniline, polypyrrole and carbon nanotubes. Then, some examples of electro-conductive membranes for permeation enhancement and fouling mitigation by electrostatic repulsion, hydrogen peroxide generation and electrochemical oxidation will be presented.

Spin diffusion in disordered organic semiconductors

Science.gov (United States)

Li, Ling; Gao, Nan; Lu, Nianduan; Liu, Ming; Bässler, Heinz

2015-12-01

An analytical theory for spin diffusion in disordered organic semiconductors is derived. It is based on percolation theory and variable range hopping in a disordered energy landscape with a Gaussian density of states. It describes universally the dependence of the spin diffusion on temperature, carrier density, material disorder, magnetic field, and electric field at the arbitrary magnitude of the Hubbard energy of charge pairs. It is found that, compared to the spin transport carried by carriers hopping, the spin exchange will hinder the spin diffusion process at low carrier density, even under the condition of a weak electric field. Importantly, under the influence of a bias voltage, anomalous spreading of the spin packet will lead to an abnormal temperature dependence of the spin diffusion coefficient and diffusion length. This explains the recent experimental data for spin diffusion length observed in Alq3.

Quantum Spin Lenses in Atomic Arrays

Directory of Open Access Journals (Sweden)

A. W. Glaetzle

2017-09-01

Full Text Available We propose and discuss quantum spin lenses, where quantum states of delocalized spin excitations in an atomic medium are focused in space in a coherent quantum process down to (essentially single atoms. These can be employed to create controlled interactions in a quantum light-matter interface, where photonic qubits stored in an atomic ensemble are mapped to a quantum register represented by single atoms. We propose Hamiltonians for quantum spin lenses as inhomogeneous spin models on lattices, which can be realized with Rydberg atoms in 1D, 2D, and 3D, and with strings of trapped ions. We discuss both linear and nonlinear quantum spin lenses: in a nonlinear lens, repulsive spin-spin interactions lead to focusing dynamics conditional to the number of spin excitations. This allows the mapping of quantum superpositions of delocalized spin excitations to superpositions of spatial spin patterns, which can be addressed by light fields and manipulated. Finally, we propose multifocal quantum spin lenses as a way to generate and distribute entanglement between distant atoms in an atomic lattice array.

Supernovae theory: study of electro-weak processes during gravitational collapse of massive stars

International Nuclear Information System (INIS)

Fantina, A.F.

2010-01-01

The physics of supernova requires the understanding of both the complex hydrodynamical phenomena (such as transfer of energy, neutrino transport, shock) as well as the microphysics related to the dense and hot matter. In the framework of type II Supernovae theory, currently most of numerical simulations that simulate the supernova core collapse up to the formation and propagation of the shock wave fail to reproduce the observed explosion of the outer layers of massive stars. The reason for that could be due both to hydrodynamical phenomena such as rotation, convection, and general relativity, and to some micro-physical processes involved in the picture and not yet completely understood. The aim of this work is to investigate some of these micro-physical inputs, namely the electro-weak processes, that play a crucial role during the gravitational collapse and to analyse their effects by means of hydrodynamical simulations. Among nuclear processes which occur in core-collapse supernova, the most important electro-weak process taking place during the collapse is the electron capture; it occurs both on free protons and on protons bound in nuclei. This capture is essential to determine the evolution of the lepton fraction of the core during the neutronization phase. It affects the efficiency of the bounce and, as a consequence, the strength of the shock wave. Moreover, both the equation of state of supernova matter and electron capture rates in nuclei are modified by the effective mass of nucleons in nuclei, induced by many-body correlations in the dense medium, and its temperature dependence. In the first part of the thesis, a nuclear model aimed at studying the nuclear effective mass is presented. We show how we have included in a energy density functional (EDF) approach a surface-peaked nucleon effective mass to mimic some effects beyond Hartree-Fock. We have added a term to the Skyrme functional, in order to reproduce the enhancement of the effective mass at the

Aging effect of spin accumulation in non-local spin valves

International Nuclear Information System (INIS)

Zhao, Bing; Zhang, Ziyu; Chen, Xiaobing; Zhang, Xiaohan; Pan, Jiahui; Ma, Jiajun; Li, Juan; Wang, Zhicheng; Wang, Le; Xu, Xiaoguang; Jiang, Yong

2017-01-01

Highlights: • First time to reveal the whole temporal evolution life of spintronics devices. • The gradual oxidation of the junctions’ areas and that of the channel are confirmed to be the predominant factors to determine the temporal evolution. • Physically, the temporal evolution can be evaluated by theories of S. Takahashi and A. Fert. • This study may offer some useful advice for the design and protection of future industrial spintronics devices. - Abstract: A temporal evolution of spin accumulation of Co/MgO/Ag spin valves have been studied by using the nonlocal spin detection technique over almost a 3-month period in the ambient environment after the fabrication of the devices. Three different stages of the spin accumulation are first observed due to aging effect. The aging effect comes from two contributions–the gradual oxidation of the Ag/MgO and MgO/Co interfaces at the junctions’ areas which arises from the annealing process and the oxidation of the side surfaces of the Ag channels. The theories of S. Takahashi and A. Fert are introduced to evaluate the different evolution stages of spin accumulation.

Aging effect of spin accumulation in non-local spin valves

Energy Technology Data Exchange (ETDEWEB)

Zhao, Bing; Zhang, Ziyu; Chen, Xiaobing; Zhang, Xiaohan; Pan, Jiahui; Ma, Jiajun; Li, Juan; Wang, Zhicheng [State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Wang, Le, E-mail: wangle@ruc.edu.cn [Department of Physics, Renmin University of China, Beijing 100872 (China); Xu, Xiaoguang, E-mail: xgxu@ustb.edu.cn [State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Jiang, Yong [State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China)

2017-06-15

Highlights: • First time to reveal the whole temporal evolution life of spintronics devices. • The gradual oxidation of the junctions’ areas and that of the channel are confirmed to be the predominant factors to determine the temporal evolution. • Physically, the temporal evolution can be evaluated by theories of S. Takahashi and A. Fert. • This study may offer some useful advice for the design and protection of future industrial spintronics devices. - Abstract: A temporal evolution of spin accumulation of Co/MgO/Ag spin valves have been studied by using the nonlocal spin detection technique over almost a 3-month period in the ambient environment after the fabrication of the devices. Three different stages of the spin accumulation are first observed due to aging effect. The aging effect comes from two contributions–the gradual oxidation of the Ag/MgO and MgO/Co interfaces at the junctions’ areas which arises from the annealing process and the oxidation of the side surfaces of the Ag channels. The theories of S. Takahashi and A. Fert are introduced to evaluate the different evolution stages of spin accumulation.

ASAP (Automatic Software for ASL Processing): A toolbox for processing Arterial Spin Labeling images.

Science.gov (United States)

Mato Abad, Virginia; García-Polo, Pablo; O'Daly, Owen; Hernández-Tamames, Juan Antonio; Zelaya, Fernando

2016-04-01

The method of Arterial Spin Labeling (ASL) has experienced a significant rise in its application to functional imaging, since it is the only technique capable of measuring blood perfusion in a truly non-invasive manner. Currently, there are no commercial packages for processing ASL data and there is no recognized standard for normalizing ASL data to a common frame of reference. This work describes a new Automated Software for ASL Processing (ASAP) that can automatically process several ASL datasets. ASAP includes functions for all stages of image pre-processing: quantification, skull-stripping, co-registration, partial volume correction and normalization. To assess the applicability and validity of the toolbox, this work shows its application in the study of hypoperfusion in a sample of healthy subjects at risk of progressing to Alzheimer's disease. ASAP requires limited user intervention, minimizing the possibility of random and systematic errors, and produces cerebral blood flow maps that are ready for statistical group analysis. The software is easy to operate and results in excellent quality of spatial normalization. The results found in this evaluation study are consistent with previous studies that find decreased perfusion in Alzheimer's patients in similar regions and demonstrate the applicability of ASAP. Copyright © 2015 Elsevier Inc. All rights reserved.

Efficient spin transport through polyaniline

Science.gov (United States)

Mendes, J. B. S.; Alves Santos, O.; Gomes, J. P.; Assis, H. S.; Felix, J. F.; Rodríguez-Suárez, R. L.; Rezende, S. M.; Azevedo, A.

2017-01-01

By using the spin pumping process, we show that it is possible to transport a pure spin current across layers of conducting polyaniline (PANI) with several hundred nanometers sandwiched between a film of the ferrimagnetic insulator yttrium iron garnet (YIG) and a thin layer of platinum. The spin current generated by microwave-driven ferromagnetic resonance of the YIG film, injected through the YIG/PANI interface, crosses the whole PANI layer and then is injected into the Pt layer. By means of the inverse spin Hall effect in the Pt, the spin current is converted into charge current and electrically detected as a dc voltage. We measured a spin diffusion length in PANI of 590 ± 40 nm, which is very large compared with normal metals, demonstrating that PANI can be used as an efficient spin current conductor and poor charge current conductor, opening the path towards spintronics applications based in this very attractive material.

Robust Hinfinity position control synthesis of an electro-hydraulic servo system.

Science.gov (United States)

Milić, Vladimir; Situm, Zeljko; Essert, Mario

2010-10-01

This paper focuses on the use of the techniques based on linear matrix inequalities for robust H(infinity) position control synthesis of an electro-hydraulic servo system. A nonlinear dynamic model of the hydraulic cylindrical actuator with a proportional valve has been developed. For the purpose of the feedback control an uncertain linearized mathematical model of the system has been derived. The structured (parametric) perturbations in the electro-hydraulic coefficients are taken into account. H(infinity) controller extended with an integral action is proposed. To estimate internal states of the electro-hydraulic servo system an observer is designed. Developed control algorithms have been tested experimentally in the laboratory model of an electro-hydraulic servo system. Copyright © 2010 ISA. Published by Elsevier Ltd. All rights reserved.

Pt/XC-72 catalysts coated with nitrogen-doped carbon (Pt/XC-72@C–N) for methanol electro-oxidation

Energy Technology Data Exchange (ETDEWEB)

Cao, Jun; Chu, Yuanyuan; Tan, Xiaoyao, E-mail: cestanxy@aliyun.com

2014-03-01

Pt/XC-72 catalysts coated with N-doped carbon (denoted as Pt/XC-72@C–N) for the electro-oxidation of methanol are prepared through a combined microwave-assisted polyol with in-situ carbonization of N-doped carbon coating process using polyvinylpyrrolidone (PVP), 1-vinyl-3-ethylimidazolium nitrate (VEIN) or 1-ethyl-3-methylimidazolium dicyanamide (EMID) ionic liquid as the N-doped carbon precursor. X-ray diffraction, energy dispersive of X-ray, transmission electron microscopy, X-ray photoelectron spectroscopy, cyclic voltammograms and accelerated aging test techniques are applied to characterize the structure and the electro-catalytic activity of the catalysts. The results show that the Pt particles with the average size of around 2.5 nm are highly dispersed in face-centered cubic crystal structure in the carbon support. The structure of the N-doped carbon coating precursor has considerable influence on the electro-catalytic performance of the catalysts. The resultant catalyst with EMID ionic liquid as the N-doped carbon source exhibits 115.9 m{sup 2} g{sup −1}Pt electrochemical surface area (ESA) and 0.66 A mg{sup −1}Pt catalytic activity towards the electro-oxidation of methanol, which are 1.37 times the ESA and 1.35 times the catalytic activity of the PVP-derived catalyst, and 2.02 times the electrochemical surface area and 1.94 times the catalytic activity of the VEIN-derived catalyst. The appropriate amount of the EMID ionic liquid used in the catalyst synthesis process is around 10 uL for 100 mg XC-72 support so as to obtain the highest electro-catalytic activity. - Highlights: • N-doped carbon coated Pt/C catalyst is prepared for methanol electro-oxidation. • Pt/XC-72@C–N exhibits excellent electrocatalytic activity over uncoated catalysts. • Ionic liquid with anionic cyano groups is most suitable as N-doped carbon precursor. • The appropriate amount of ionic liquid for coating is around 10 μL for 100 mg carbon.

Chemical vapor deposition graphene transfer process to a polymeric substrate assisted by a spin coater

International Nuclear Information System (INIS)

Kessler, Felipe; Da Rocha, Caique O C; Medeiros, Gabriela S; Fechine, Guilhermino J M

2016-01-01

A new method to transfer chemical vapor deposition graphene to polymeric substrates is demonstrated here, it is called direct dry transfer assisted by a spin coater (DDT-SC). Compared to the conventional method DDT, the improvement of the contact between graphene-polymer due to a very thin polymeric film deposited by spin coater before the transfer process prevented air bubbles and/or moisture and avoided molecular expansion on the graphene-polymer interface. An acrylonitrile-butadiene-styrene copolymer, a high impact polystyrene, polybutadiene adipate-co-terephthalate, polylactide acid, and a styrene-butadiene-styrene copolymer are the polymers used for the transfers since they did not work very well by using the DDT process. Raman spectroscopy and optical microscopy were used to identify, to quantify, and to qualify graphene transferred to the polymer substrates. The quantity of graphene transferred was substantially increased for all polymers by using the DDT-SC method when compared with the DDT standard method. After the transfer, the intensity of the D band remained low, indicating low defect density and good quality of the transfer. The DDT-SC transfer process expands the number of graphene applications since the polymer substrate candidates are increased. (paper)

Towards spin injection into silicon

Energy Technology Data Exchange (ETDEWEB)

Dash, S.P.

2007-08-15

Si has been studied for the purpose of spin injection extensively in this thesis. Three different concepts for spin injection into Si have been addressed: (1) spin injection through a ferromagnet-Si Schottky contact, (2) spin injection using MgO tunnel barriers in between the ferromagnet and Si, and (3) spin injection from Mn-doped Si (DMS) as spin aligner. (1) FM-Si Schottky contact for spin injection: To be able to improve the interface qualities one needs to understand the atomic processes involved in the formation of silicide phases. In order to obtain more detailed insight into the formation of such phases the initial stages of growth of Co and Fe were studied in situ by HRBS with monolayer depth resolution.(2) MgO tunnel barrier for spin injection into Si: The fabrication and characterization of ultra-thin crystalline MgO tunnel barriers on Si (100) was presented. (3) Mn doped Si for spin injection: Si-based diluted magnetic semiconductor samples were prepared by doping Si with Mn by two different methods i) by Mn ion implantation and ii) by in-diffusion of Mn atoms (solid state growth). (orig.)

Design of a Novel Electro-hydraulic Drive Downhole Tractor

Science.gov (United States)

Fang, Delei; Shang, Jianzhong; Yang, Junhong; Wang, Zhuo; Wu, Wei

2018-02-01

In order to improve the traction ability and the work efficiency of downhole tractor in oil field, a novel electro-hydraulic drive downhole tractor was designed. The tractor’s supporting mechanism and moving mechanism were analyzed based on the tractor mechanical structure. Through the introduction of hydraulic system, the hydraulic drive mechanism and the implementation process were researched. Based on software, analysis of tractor hydraulic drive characteristic and movement performance were simulated, which provide theoretical basis for the development of tractor prototype.

Production of spin-polarized unstable nuclei by using polarized electron capture process

International Nuclear Information System (INIS)

Shimizu, S.

1998-01-01

Measurements of emitted radiation from spin polarized nuclei are used to get information on electromagnetic moment of ground state unstable nuclei together with spin or parity state of excited states of their decayed (daughter) nuclei. These data are known to be useful for experimental investigation into the structure of unstable nuclei far from the stability line. The present study aims to establish a general method applicable to 11 Be and 16 N nuclei. To produce spin polarization, a new method in which the electron spin polarization of Rb is firstly produced by laser pumping, then the electron is transferred to the unstable nuclear beam (RNB) when they passes through the Rb vapor is proposed. Finally the polarized RNB will be implanted into superfluid helium to remain with a long spin-relaxation time. Future experimental set up for the above measurement adopted in the available radioactive nuclear beam facilities is briefly described. (Ohno, S.)

Missile Electro-Optical Countermeasures Simulation Laboratory

Data.gov (United States)

Federal Laboratory Consortium — This laboratory comprises several hardware-in-the-loop missile flight simulations designed specifically to evaluate the effectiveness of electro-optical air defense...

Modification of Patterned Nanoporous Gold Thin Film Electrodes via Electro-annealing and Electrochemical Etching

Science.gov (United States)

Dorofeeva, Tatiana

Nanostructured materials have had a major impact on various fields, including medicine, catalysis, and energy storage, for the major part due to unique phenomena that arise at nanoscale. For this reason, there is a sustained need for new nanostructured materials, techniques to pattern them, and methods to precisely control their nanostructure. To that end, the primary focus of this dissertation is to demonstrate novel techniques to fabricate and tailor the morphology of a class of nanoporous metals, obtained by a process known as dealloying. In this process, while the less noble constituent of an alloy is chemically dissolved, surface-diffusion of the more noble constituent leads to self-assembly of a bicontinuous ligament network with characteristic porosity of ˜70% and ligament diameter of 10s of nanometers. As a model material produced by dealloying, this work employ nanoporous gold (np-Au), which has attracted significant attention of desirable features, such as high effective surface area, electrical conductivity, well-defined thiol-based surface modification strategies, microfabrication-compatibility, and biocompatibility. The most commonly method used to modify the morphology of np-Au is thermal treatment, where the enhanced diffusivity of the surface atoms leads to ligament (and consequently pore) coarsening. This method, however, is not conducive to modifying the morphology of thin films at specific locations on the film, which is necessary for creating devices that may need to contain different morphologies on a single device. In addition, coarsening attained by thermal treatment also leads to an undesirable reduction in effective surface area. In response to these challenges, this work demonstrates two different techniques that enables in situ modification of np-Au thin film electrodes obtained by sputter-deposition of a precursors silver-rich gold-silver alloy. The first method, referred to as electro-annealing, is achieved by injecting electrical

Spin-dependent recombination processes in wide band gap II-Mn-VI compounds

International Nuclear Information System (INIS)

Godlewski, M.; Yatsunenko, S.; Khachapuridze, A.; Ivanov, V.Yu.

2004-01-01

Mechanisms of optical detection of magnetic resonance in wide band gap II-Mn-VI diluted magnetic semiconductor (DMS) are discussed based on the results of photoluminescence (PL), PL kinetics, electron spin resonance (ESR) and optically detected magnetic resonance (ODMR) and optically detected cyclotron resonance (ODCR) investigations. Spin-dependent interactions between localized spins of Mn 2+ ions and spins/magnetic moments of free, localized or bound carriers are responsible for the observed ODMR signals. We conclude that these interactions are responsible for the observed rapid shortening of the PL decay time of 4 T 1 → 6 A 1 intra-shell emission of Mn 2+ ions and also for the observed delocalization of excitons in low dimensional structures

SPINS OF LARGE ASTEROIDS: A HINT OF A PRIMORDIAL DISTRIBUTION IN THEIR SPIN RATES

Energy Technology Data Exchange (ETDEWEB)

Steinberg, Elad; Sari, Re’em [The Hebrew University of Jerusalem, Jerusalem (Israel)

2015-04-15

The Asteroid Belt and the Kuiper Belt are relics from the formation of our solar system. Understanding the size and spin distribution of the two belts is crucial for a deeper understanding of the formation of our solar system and the dynamical processes that govern it. In this paper, we investigate the effect of collisions on the evolution of the spin distribution of asteroids and KBOs. We find that the power law nature of the impactors’ size distribution leads to a Lévy distribution of the spin rates. This results in a power law tail in the spin distribution, in stark contrast to the usually quoted Maxwellian distribution. We show that for bodies larger than 10 km, collisions alone lead to spin rates peaking at 0.15–0.5 revolutions per day. Comparing that to the observed spin rates of large asteroids (R > 50 km), we find that the spins of large asteroids, peaking at ∼1–2 revolutions per day, are dominated by a primordial component that reflects the formation mechanism of the asteroids. Similarly, the Kuiper Belt has undergone virtually no collisional spin evolution, assuming current densities. Collisions contribute a spin rate of ∼0.01 revolutions per day, thus the observed fast spin rates of KBOs are also primordial in nature.

Hybrid bio-photo-electro-chemical cells for solar water splitting

OpenAIRE

Pinhassi, Roy I.; Kallmann, Dan; Saper, Gadiel; Dotan, Hen; Linkov, Artyom; Kay, Asaf; Liveanu, Varda; Schuster, Gadi; Adir, Noam; Rothschild, Avner

2016-01-01

Photoelectrochemical water splitting uses solar power to decompose water to hydrogen and oxygen. Here we show how the photocatalytic activity of thylakoid membranes leads to overall water splitting in a bio-photo-electro-chemical (BPEC) cell via a simple process. Thylakoids extracted from spinach are introduced into a BPEC cell containing buffer solution with ferricyanide. Upon solar-simulated illumination, water oxidation takes place and electrons are shuttled by the ferri/ferrocyanide redox...

Helicity formalism and spin effects

International Nuclear Information System (INIS)

Anselmino, M.; Caruso, F.; Piovano, U.

1990-01-01

The helicity formalism and the technique to compute amplitudes for interaction processes involving leptons, quarks, photons and gluons are reviewed. Explicit calculations and examples of exploitation of symmetry properties are shown. The formalism is then applied to the discussion of several hadronic processes and spin effects: the experimental data, when related to the properties of the elementary constituent interactions, show many not understood features. Also the nucleon spin problem is briefly reviewed. (author)

Spin manipulation and spin-lattice interaction in magnetic colloidal quantum dots

Science.gov (United States)

Moro, Fabrizio; Turyanska, Lyudmila; Granwehr, Josef; Patanè, Amalia

2014-11-01

We report on the spin-lattice interaction and coherent manipulation of electron spins in Mn-doped colloidal PbS quantum dots (QDs) by electron spin resonance. We show that the phase memory time,TM , is limited by Mn-Mn dipolar interactions, hyperfine interactions of the protons (1H) on the QD capping ligands with Mn ions in their proximity (limit and at low temperature, we achieve a long phase memory time constant TM˜0.9 μ s , thus enabling the observation of Rabi oscillations. Our findings suggest routes to the rational design of magnetic colloidal QDs with phase memory times exceeding the current limits of relevance for the implementation of QDs as qubits in quantum information processing.

Numerical study on physical mechanism of vortex breakdown occurrence in spin-up process

OpenAIRE

"小出, 輝明"; Teruaki", "Koide

2008-01-01

"A Numerical study presented on a vortex breakdown in spin-up process in an enclosed cylindrical container. In a transitional state, momentary vortex breakdowns can occur for particular parameter values ofthe Reynolds number and aspect ratio where no vortex breakdown appears in a steady state. This transient vortex breakdown flow is convenient to consider a mechanism for the occurrence of a vortex breakdown. It isdiscussed that periodical increase and decrease of angular momentum in upstream ...

Analysis of microstructure in electro-spark deposited IN718 superalloy

Energy Technology Data Exchange (ETDEWEB)

Anisimov, E.; Khan, A.K.; Ojo, O.A., E-mail: olanrewaju.ojo@umanitoba.ca

2016-09-15

The microstructure of electro-spark deposited (ESD) superalloy IN718 was studied by the use of scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) techniques. In converse to general assumption, the extremely high cooling rate involved in the ESD process did not produce partitionless solidification that is devoid of second phase microconstituents in the material, nano-sized Laves phase and MC carbide particles were observed within the deposited layer. Notwithstanding the several thermal cycles involved in the process, the extremely low heat input of the process produced a deposited region that is free of the main strengthening phase of the alloy, γ″ phase precipitates, which is in contrast to what have been reported on laser deposition. Nevertheless, application of the standard full heat treatment of the alloy resulted in extensive formation of the γ″ phase precipitates and δ phase precipitates, the most stable secondary phase of the alloy, with nearly, if not complete, dissolution of the Laves phase particles. Furthermore, the XPS analysis done in the study revealed the formation of nano-oxides within the deposited layer, which increased the microhardness of the superalloy in the as-deposited condition and inhibited its grain growth during post-process heat treatment. The microstructure analysis done in this work is crucial to the understanding of properties of the superalloy processed by the ESD technique. - Highlights: •Electron microscopy analyses of electro-spark deposited IN 718 superalloy were performed. •Nano-sized secondary phase particles were observed within the deposited layer. •The study shows that the ESD did not produce partitionless solidification of the alloy.

The importance of spinning speed in fabrication of spin-coated organic thin film transistors: Film morphology and field effect mobility

International Nuclear Information System (INIS)

Kotsuki, Kenji; Tanaka, Hiroshige; Obata, Seiji; Stauss, Sven; Terashima, Kazuo; Saiki, Koichiro

2014-01-01

We have investigated the film morphology and the field effect mobility of 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) thin films which were formed by spin coating on the SiO 2 substrate with solution-processed graphene electrodes. The domain size and the density of aggregates in the C8-BTBT film showed the same dependence on the spinning speed. These competitive two factors (domain size and density of aggregates) give an optimum spinning speed, at which the field effect mobility of C8-BTBT transistor showed a maximum (2.6 cm 2 /V s). This result indicates the importance of spinning speed in the fabrication of solution processed organic thin film transistors by spin coating.

Spin Flips versus Spin Transport in Nonthermal Electrons Excited by Ultrashort Optical Pulses in Transition Metals

Science.gov (United States)

Shokeen, V.; Sanchez Piaia, M.; Bigot, J.-Y.; Müller, T.; Elliott, P.; Dewhurst, J. K.; Sharma, S.; Gross, E. K. U.

2017-09-01

A joint theoretical and experimental investigation is performed to understand the underlying physics of laser-induced demagnetization in Ni and Co films with varying thicknesses excited by 10 fs optical pulses. Experimentally, the dynamics of spins is studied by determining the time-dependent amplitude of the Voigt vector, retrieved from a full set of magnetic and nonmagnetic quantities performed on both sides of films, with absolute time reference. Theoretically, ab initio calculations are performed using time-dependent density functional theory. Overall, we demonstrate that spin-orbit induced spin flips are the most significant contributors with superdiffusive spin transport, which assumes only that the transport of majority spins without spin flips induced by scattering does not apply in Ni. In Co it plays a significant role during the first ˜20 fs only. Our study highlights the material dependent nature of the demagnetization during the process of thermalization of nonequilibrium spins.

Spin current evolution in the separated spin-up and spin-down quantum hydrodynamics

International Nuclear Information System (INIS)

Trukhanova, Mariya Iv.

2015-01-01

We have developed a method of quantum hydrodynamics (QHD) that describes particles with spin-up and with spin-down in separate. We have derived the equation of the spin current evolution as a part of the set of the quantum hydrodynamics equations that treat particles with different projection of spin on the preferable direction as two different species. We have studied orthogonal propagation of waves in the external magnetic field and determined the contribution of quantum corrections due to the Bohm potential and to magnetization energy of particles with different projections of spin in the spin-current wave dispersion. We have analyzed the limits of weak and strong magnetic fields. - Highlights: • We derive the spin current equation for particles with different projection of spin. • We predict the contribution of Bohm potential to the dynamics of spin current. • We derive the spin-current wave in the system of spin-polarized particles. • We study the propagation of spin-acoustic wave in magnetized dielectrics.

Cardiac and electro-cortical concomitants of social feedback processing in women

Science.gov (United States)

van der Molen, Melle J. W.; Gunther Moor, Bregtje; van der Veen, Frederik M.; van der Molen, Maurits W.

2015-01-01

This study provides a joint analysis of the cardiac and electro-cortical—early and late P3 and feedback-related negativity (FRN)—responses to social acceptance and rejection feedback. Twenty-five female participants performed on a social- and age-judgment control task, in which they received feedback with respect to their liking and age judgments, respectively. Consistent with previous reports, results revealed transient cardiac slowing to be selectively prolonged to unexpected social rejection feedback. Late P3 amplitude was more pronounced to unexpected relative to expected feedback. Both early and late P3 amplitudes were shown to be context dependent, in that they were more pronounced to social as compared with non-social feedback. FRN amplitudes were more pronounced to unexpected relative to expected feedback, irrespective of context and feedback valence. This pattern of findings indicates that social acceptance and rejection feedback have widespread effects on bodily state and brain function, which are modulated by prior expectancies. PMID:25870439

Using iron-loaded sepiolite obtained by adsorption as a catalyst in the electro-Fenton oxidation of Reactive Black 5.

Science.gov (United States)

Iglesias, O; Fernández de Dios, M A; Pazos, M; Sanromán, M A

2013-09-01

This study explores the possibility of using iron-loaded sepiolite, obtained by recovering iron from polluted water, as a catalyst in the electro-Fenton oxidation of organic pollutants in textile effluents. The removal of iron ions from aqueous solution by adsorption on sepiolite was studied in batch tests at iron concentrations between 100 and 1,000 ppm. Electro-Fenton experiments were carried out in an electrochemical cell with a working volume of 0.15 L, an air flow of 1 L/min, and 3 g of iron-loaded sepiolite. An electric field was applied using a boron-doped diamond anode and a graphite sheet cathode connected to a direct current power supply with a constant potential drop. Reactive Black 5 (100 mg/L) was selected as the model dye. The adsorption isotherms proved the ability of the used adsorbent. The removal of the iron ion by adsorption on sepiolite was in the range of 80-100 % for the studied concentration range. The Langmuir and Freundlich isotherms were found to be applicable in terms of the relatively high regression values. Iron-loaded sepiolite could be used as an effective heterogeneous catalyst for the degradation of organic dyes in the electro-Fenton process. Successive batch processes were performed at optimal working conditions (5 V and pH 2). The results indicate the suitability of the proposed combined process, adsorption to iron remediation followed by the application of the obtained iron-loaded sepiolite to the electro-Fenton technique, to oxidize polluted effluents.

Green Synthesis of Three-Dimensional Hybrid N-Doped ORR Electro-Catalysts Derived from Apricot Sap

Directory of Open Access Journals (Sweden)

Ramesh Karunagaran

2018-01-01

Full Text Available Rapid depletion of fossil fuel and increased energy demand has initiated a need for an alternative energy source to cater for the growing energy demand. Fuel cells are an enabling technology for the conversion of sustainable energy carriers (e.g., renewable hydrogen or bio-gas into electrical power and heat. However, the hazardous raw materials and complicated experimental procedures used to produce electro-catalysts for the oxygen reduction reaction (ORR in fuel cells has been a concern for the effective implementation of these catalysts. Therefore, environmentally friendly and low-cost oxygen reduction electro-catalysts synthesised from natural products are considered as an attractive alternative to currently used synthetic materials involving hazardous chemicals and waste. Herein, we describe a unique integrated oxygen reduction three-dimensional composite catalyst containing both nitrogen-doped carbon fibers (N-CF and carbon microspheres (N-CMS synthesised from apricot sap from an apricot tree. The synthesis was carried out via three-step process, including apricot sap resin preparation, hydrothermal treatment, and pyrolysis with a nitrogen precursor. The nitrogen-doped electro-catalysts synthesised were characterised by SEM, TEM, XRD, Raman, and BET techniques followed by electro-chemical testing for ORR catalysis activity. The obtained catalyst material shows high catalytic activity for ORR in the basic medium by facilitating the reaction via a four-electron transfer mechanism.

Green Synthesis of Three-Dimensional Hybrid N-Doped ORR Electro-Catalysts Derived from Apricot Sap.

Science.gov (United States)

Karunagaran, Ramesh; Coghlan, Campbell; Shearer, Cameron; Tran, Diana; Gulati, Karan; Tung, Tran Thanh; Doonan, Christian; Losic, Dusan

2018-01-28

Rapid depletion of fossil fuel and increased energy demand has initiated a need for an alternative energy source to cater for the growing energy demand. Fuel cells are an enabling technology for the conversion of sustainable energy carriers (e.g., renewable hydrogen or bio-gas) into electrical power and heat. However, the hazardous raw materials and complicated experimental procedures used to produce electro-catalysts for the oxygen reduction reaction (ORR) in fuel cells has been a concern for the effective implementation of these catalysts. Therefore, environmentally friendly and low-cost oxygen reduction electro-catalysts synthesised from natural products are considered as an attractive alternative to currently used synthetic materials involving hazardous chemicals and waste. Herein, we describe a unique integrated oxygen reduction three-dimensional composite catalyst containing both nitrogen-doped carbon fibers (N-CF) and carbon microspheres (N-CMS) synthesised from apricot sap from an apricot tree. The synthesis was carried out via three-step process, including apricot sap resin preparation, hydrothermal treatment, and pyrolysis with a nitrogen precursor. The nitrogen-doped electro-catalysts synthesised were characterised by SEM, TEM, XRD, Raman, and BET techniques followed by electro-chemical testing for ORR catalysis activity. The obtained catalyst material shows high catalytic activity for ORR in the basic medium by facilitating the reaction via a four-electron transfer mechanism.

Demonstration of a robust magnonic spin wave interferometer.

Science.gov (United States)

Kanazawa, Naoki; Goto, Taichi; Sekiguchi, Koji; Granovsky, Alexander B; Ross, Caroline A; Takagi, Hiroyuki; Nakamura, Yuichi; Inoue, Mitsuteru

2016-07-22

Magnonics is an emerging field dealing with ultralow power consumption logic circuits, in which the flow of spin waves, rather than electric charges, transmits and processes information. Waves, including spin waves, excel at encoding information via their phase using interference. This enables a number of inputs to be processed in one device, which offers the promise of multi-input multi-output logic gates. To realize such an integrated device, it is essential to demonstrate spin wave interferometers using spatially isotropic spin waves with high operational stability. However, spin wave reflection at the waveguide edge has previously limited the stability of interfering waves, precluding the use of isotropic spin waves, i.e., forward volume waves. Here, a spin wave absorber is demonstrated comprising a yttrium iron garnet waveguide partially covered by gold. This device is shown experimentally to be a robust spin wave interferometer using the forward volume mode, with a large ON/OFF isolation value of 13.7 dB even in magnetic fields over 30 Oe.

Neutron spin quantum precession using multilayer spin splitters and a phase-spin echo interferometer

International Nuclear Information System (INIS)

Ebisawa, Toru; Tasaki, Seiji; Kawai, Takeshi; Hino, Masahiro; Akiyoshi, Tsunekazu; Achiwa, Norio; Otake, Yoshie; Funahashi, Haruhiko.

1996-01-01

Neutron spin quantum precession by multilayer spin splitter has been demonstrated using a new spin interferometer. The multilayer spin splitter consists of a magnetic multilayer mirror on top, followed by a gap layer and a non magnetic multilayer mirror which are evaporated on a silicon substrate. Using the multilayer spin splitter, a polarized neutron wave in a magnetic field perpendicular to the polarization is split into two spin eigenstates with a phase shift in the direction of the magnetic field. The spin quantum precession is equal to the phase shift, which depends on the effective thickness of the gap layer. The demonstration experiments verify the multilayer spin splitter as a neutron spin precession device as well as the coherent superposition principle of the two spin eigenstates. We have developed a new phase-spin echo interferometer using the multilayer spin splitters. We present successful performance tests of the multilayer spin splitter and the phase-spin echo interferometer. (author)

Recent highlights in electro-driven separations- selected applications of alkylthiol gold nanoparticles in capillary electrophoresis and capillary electro-chromatography.

Science.gov (United States)

Guihen, Elizabeth

2017-09-01

To date, alkylthiol gold nanoparticles (AuNPs) have been widely used in electro-chromatographic separation techniques as a viable alternative to traditional stationary phases. This is mainly due to their stability, chemical inertness, ease of functionality, increased phase ratio, ability to form self-assembled monolayers. They also yield versatile stationary phases with highly specific targeted functionalities. At the nanoscale region, the chemical and physical properties of a molecule display different attributes to that of the parent molecules or material, hence these features can be harnessed in electro-driven chromatographic separations. Application areas illustrating the use of AuNPs in separation science continue to grow and expand to cover many different kinds of analysis. The last decade has witnessed a successful trend in miniaturisation of chemical separation systems toward the micro and nanoscale ranges. Nanoparticle-based stationary phases fit well with performing chemical separations on microfluidic and capillary platforms. In this review the theory of the use of alkylthiol gold nanoparticles in electro-chromatographic driven separation methods will be discussed. This will be followed by details of recent and selected applications showing alkylthiol gold nanoparticles in capillary electrophoretic and open-tubular electro-chromatographic separations. This review will focus solely on alkylthiol based gold nanoparticles, therefore other kinds of chemical moieties bonded to gold nanoparticles are outside the scope of this review. Finally the future outlook of this exciting technology will be outlined in some detail in the final section. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Concrete decontamination by electro-hydraulic scabbling

Energy Technology Data Exchange (ETDEWEB)

Goldfarb, V.; Gannon, R. [Textron Defense System, Everett, MA (United States)

1995-10-01

Textron Defense Systems (TDS) is developing an electro-hydraulic device that has the potential for faster, safer, and less expensive scabbling of contaminated concrete surfaces. In the device, shock waves and cavitating bubbles are produced in water by the electric pulses, and the direct and reflected shock waves impinging on the concrete surface result in the crushing and cracking of the concrete. Pulse energy, frequency, and traverse speed control the depth of the scabbling action. Performance thus far has demonstrated the capability of a prototype unit to process a swath 24 inches wide, up to 3/4 inch deep at a linear velocity of up to 6 feet per hour, i.e., at a scabbling rate of 12 sq. ft. per hour.

Concrete decontamination by electro-hydraulic scabbling

International Nuclear Information System (INIS)

Goldfarb, V.; Gannon, R.

1995-01-01

Textron Defense Systems (TDS) is developing an electro-hydraulic device that has the potential for faster, safer, and less expensive scabbling of contaminated concrete surfaces. In the device, shock waves and cavitating bubbles are produced in water by the electric pulses, and the direct and reflected shock waves impinging on the concrete surface result in the crushing and cracking of the concrete. Pulse energy, frequency, and traverse speed control the depth of the scabbling action. Performance thus far has demonstrated the capability of a prototype unit to process a swath 24 inches wide, up to 3/4 inches deep at a linear velocity of up to 6 feet per hour, i.e., at a scabbling rate of 12 sq. ft. per hour

Sol-Gel Material-Enabled Electro-Optic Polymer Modulators

Science.gov (United States)

Himmelhuber, Roland; Norwood, Robert A.; Enami, Yasufumi; Peyghambarian, Nasser

2015-01-01

Sol-gels are an important material class, as they provide easy modification of material properties, good processability and are easy to synthesize. In general, an electro-optic (EO) modulator transforms an electrical signal into an optical signal. The incoming electrical signal is most commonly information encoded in a voltage change. This voltage change is then transformed into either a phase change or an intensity change in the light signal. The less voltage needed to drive the modulator and the lower the optical loss, the higher the link gain and, therefore, the better the performance of the modulator. In this review, we will show how sol-gels can be used to enhance the performance of electro-optic modulators by allowing for designs with low optical loss, increased poling efficiency and manipulation of the electric field used for driving the modulator. The optical loss is influenced by the propagation loss in the device, as well as the losses occurring during fiber coupling in and out of the device. In both cases, the use of sol-gel materials can be beneficial due to the wide range of available refractive indices and low optical attenuation. The influence of material properties and synthesis conditions on the device performance will be discussed. PMID:26225971

Optical and electro-optic anisotropy of epitaxial PZT thin films

Science.gov (United States)

Zhu, Minmin; Du, Zehui; Jing, Lin; Yoong Tok, Alfred Iing; Tong Teo, Edwin Hang

2015-07-01

Strong optical and electro-optic (EO) anisotropy has been investigated in ferroelectric Pb(Zr0.48Ti0.52)O3 thin films epitaxially grown on Nb-SrTiO3 (001), (011), and (111) substrates using magnetron sputtering. The refractive index, electro-optic, and ferroelectric properties of the samples demonstrate the significant dependence on the growth orientation. The linear electro-optic coefficients of the (001), (011), and (111)-oriented PZT thin films were 270.8, 198.8, and 125.7 pm/V, respectively. Such remarkable anisotropic EO behaviors have been explained according to the structure correlation between the orientation dependent distribution, spontaneous polarization, epitaxial strain, and domain pattern.

In search of elementary spin 0 particles

International Nuclear Information System (INIS)

Krasny, Mieczyslaw Witold; Płaczek, Wiesław

2015-01-01

The Standard Model of strong and electroweak interactions uses point-like spin 1/2 particles as the building bricks of matter and point-like spin 1 particles as the force carriers. One of the most important questions to be answered by the present and future particle physics experiments is whether the elementary spin 0 particles exist, and if they do, what are their interactions with the spin 1/2 and spin 1 particles. Spin 0 particles have been searched extensively over the last decades. Several initial claims of their discoveries were finally disproved in the final experimental scrutiny process. The recent observation of the excess of events at the LHC in the final states involving a pair of vector bosons, or photons, is commonly interpreted as the discovery of the first elementary scalar particle, the Higgs boson. In this paper we recall examples of claims and subsequent disillusions in precedent searches spin 0 particles. We address the question if the LHC Higgs discovery can already be taken for granted, or, as it turned out important in the past, whether it requires a further experimental scrutiny before the existence of the first ever found elementary scalar particle is proven beyond any doubt. An example of the Double Drell–Yan process for which such a scrutiny is indispensable is discussed in some detail. - Highlights: • We present a short history of searches of spin 0 particles. • We construct a model of the Double Drell–Yan Process (DDYP) at the LHC. • We investigate the contribution of the DDYP to the Higgs searches background

SPIN-selling

CERN Document Server

Rackham, Neil

1995-01-01

True or false? In selling high-value products or services: "closing" increases your chance of success; it is essential to describe the benefits of your product or service to the customer; objection handling is an important skill; and open questions are more effective than closed questions. All false, says Neil Rackham. He and his team studied more than 35,000 sales calls made by 10,000 sales people in 23 countries over 12 years. Their findings revealed that many of the methods developed for selling low-value goods just don't work for major sales. Rackham went on to introduce his SPIN-selling method, where SPIN describes the whole selling process - Situation questions, Problem questions, Implication questions, Need-payoff questions. SPIN-selling provides you with a set of simple and practical techniques which have been tried in many of today's leading companies with dramatic improvements to their sales performance.

Chaotic micromixer utilizing electro-osmosis and induced charge electro-osmosis in eccentric annulus

International Nuclear Information System (INIS)

Feng, Huicheng; Wong, Teck Neng; Marcos; Che, Zhizhao

2016-01-01

Efficient mixing is of significant importance in numerous chemical and biomedical applications but difficult to realize rapidly in microgeometries due to the lack of turbulence. We propose to enhance mixing by introducing Lagrangian chaos through electro-osmosis (EO) or induced charge electro-osmosis (ICEO) in an eccentric annulus. The analysis reveals that the created Lagrangian chaos can achieve a homogeneous mixing much more rapidly than either the pure EO or the pure ICEO. Our systematic investigations on the key parameters, ranging from the eccentricity, the alternating time period, the number of flow patterns in one time period, to the specific flow patterns utilized for the Lagrangian chaos creation, present that the Lagrangian chaos is considerably robust. The system can obtain a good mixing effect with wide ranges of eccentricity, alternating time period, and specific flow patterns utilized for the Lagrangian chaos creation as long as the number of flow patterns in one time period is two. As the electric field increases, the time consumption for homogenous mixing is reduced more remarkably for the Lagrangian chaos of the ICEO than that of the EO.

Chaotic micromixer utilizing electro-osmosis and induced charge electro-osmosis in eccentric annulus

Energy Technology Data Exchange (ETDEWEB)

Feng, Huicheng; Wong, Teck Neng, E-mail: mtnwong@ntu.edu.sg; Marcos [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Che, Zhizhao [State Key Laboratory of Engines, Tianjin University, Tianjin 300072 (China)

2016-06-15

Efficient mixing is of significant importance in numerous chemical and biomedical applications but difficult to realize rapidly in microgeometries due to the lack of turbulence. We propose to enhance mixing by introducing Lagrangian chaos through electro-osmosis (EO) or induced charge electro-osmosis (ICEO) in an eccentric annulus. The analysis reveals that the created Lagrangian chaos can achieve a homogeneous mixing much more rapidly than either the pure EO or the pure ICEO. Our systematic investigations on the key parameters, ranging from the eccentricity, the alternating time period, the number of flow patterns in one time period, to the specific flow patterns utilized for the Lagrangian chaos creation, present that the Lagrangian chaos is considerably robust. The system can obtain a good mixing effect with wide ranges of eccentricity, alternating time period, and specific flow patterns utilized for the Lagrangian chaos creation as long as the number of flow patterns in one time period is two. As the electric field increases, the time consumption for homogenous mixing is reduced more remarkably for the Lagrangian chaos of the ICEO than that of the EO.

Global positioning of spin GPS scheme for half-spin massive spinors

CERN Document Server

Jadach, Stanislaw; Was, Zbigniew

2001-01-01

We present a simple and flexible method of keeping track of the complex phases and spin quantisation axes for half-spin initial- and final-state Weyl spinors in scattering amplitudes of Standard Model high energy physics processes. Both cases of massless and massive spinors are discussed. The method is demonstrated and checked numerically for spin correlations in tau tau production and decay. Its application is in our work of combining effects due to multiple photon emission (exponentiation) and spin, embodied in the Monte Carlo event generators for production and decay of unstable fermions such as the, tau lepton, t-quark and hypothetical new heavy particles. In particular, the recurrent problem of combining, for such unstable fermions, one author's calculation of production and another author's calculation of decay, in the presence or absence of multiple photon effects, is there given a practical solution, both for Weyl spinor methods and for the traditional Jacob-Wick helicity methods. Moreover, for massiv...

Analysis of cracks generated in the spinning-mandrel teeth

Directory of Open Access Journals (Sweden)

M. Haghshenas

2014-10-01

Full Text Available The spinning process, using a splined mandrel, is always prone to premature failure of the splined mandrels. Such a failure is thought to be related to the magnitude of the forming forces exerted on the mandrel by the forming rollers during the spinning process. In the present paper, the characteristic of corner cracks in the mandrel teeth (made of S7 tool steel of a spinning process has been investigated. The rotational speed of the mandrel is about 300 rpm during spinning process and the sheet metal (i.e. AISI 1020 is in contact with mandrel teeth to get the mandrel shape at the end of process. During this process, the mandrel teeth eventually break away. Fractography analyses using scanning electron microscopy (SEM clearly confirm “fatigue” as being the main reason for the failure.

Design of Electro-Mechanical Dual-Acting Pulley Continuously Variable Transmission

Directory of Open Access Journals (Sweden)

K.B. Tawi

2015-06-01

Full Text Available Pulley-based continuously variable transmission (CVT with a metal pushing V-belt is fast becoming the preferred choice for global carmakers due to its potential particularly in terms of fuel efficiency thanks to its continuous and wide ratio range. Nevertheless, the existing CVTs still face the issues of high power consumption from the engine because of the application of an electro-hydro-mechanical (EHM actuation system for its ratio changing process and clamping force mechanism. To address this issue, researchers from Universiti Teknologi Malaysia have successfully developed the prototype of an electro-mechanical dual-acting pulley continuously variable transmission (EMDAP CVT for automotive applications. The prototype of EMDAP CVT is developed for a maximum input torque of 160 Nm with the application of a metal pushing V-belt. The results from the testing prove that the prototype can vary its ratio from 2.8 to 0.6 and no continuous power is required to maintain a constant CVT ratio. These results suggest that the prototype is workable and future testing in a real car is possible.

Giant titanium electron wave function in gallium oxide: A potential electron-nuclear spin system for quantum information processing

Science.gov (United States)

Mentink-Vigier, Frédéric; Binet, Laurent; Vignoles, Gerard; Gourier, Didier; Vezin, Hervé

2010-11-01

The hyperfine interactions of the unpaired electron with eight surrounding G69a and G71a nuclei in Ti-doped β-Ga2O3 were analyzed by electron paramagnetic resonance (EPR) and electron-nuclear double resonance (ENDOR) spectroscopies. They are dominated by strong isotropic hyperfine couplings due to a direct Fermi contact interaction with Ga nuclei in octahedral sites of rutile-type chains oriented along b axis, revealing a large anisotropic spatial extension of the electron wave function. Titanium in β-Ga2O3 is thus best described as a diffuse (Ti4+-e-) pair rather than as a localized Ti3+ . Both electron and G69a nuclear spin Rabi oscillations could be observed by pulsed EPR and pulsed ENDOR, respectively. The electron spin decoherence time is about 1μs (at 4 K) and an upper bound of 520μs (at 8 K) is estimated for the nuclear decoherence time. Thus, β-Ga2O3:Ti appears to be a potential spin-bus system for quantum information processing with a large nuclear spin quantum register.

Electro-biocatalytic production of formate from carbon dioxide using an oxygen-stable whole cell biocatalyst.

Science.gov (United States)

Hwang, Hyojin; Yeon, Young Joo; Lee, Sumi; Choe, Hyunjun; Jang, Min Gee; Cho, Dae Haeng; Park, Sehkyu; Kim, Yong Hwan

2015-06-01

The use of biocatalysts to convert CO2 into useful chemicals is a promising alternative to chemical conversion. In this study, the electro-biocatalytic conversion of CO2 to formate was attempted with a whole cell biocatalyst. Eight species of Methylobacteria were tested for CO2 reduction, and one of them, Methylobacterium extorquens AM1, exhibited an exceptionally higher capability to synthesize formate from CO2 by supplying electrons with electrodes, which produced formate concentrations of up to 60mM. The oxygen stability of the biocatalyst was investigated, and the results indicated that the whole cell catalyst still exhibited CO2 reduction activity even after being exposed to oxygen gas. From the results, we could demonstrate the electro-biocatalytic conversion of CO2 to formate using an obligate aerobe, M. extorquens AM1, as a whole cell biocatalyst without providing extra cofactors or hydrogen gas. This electro-biocatalytic process suggests a promising approach toward feasible way of CO2 conversion to formate. Copyright © 2015 Elsevier Ltd. All rights reserved.

Nanofiber Manufacture, Properties, and Applications

International Nuclear Information System (INIS)

Lin, T.; Lukas, D.; Bhat, G.S.

2013-01-01

Nano fibers have shown many unique characteristics and enormous application potential in widely diverse areas. While considerable research has been conducted on exploring the properties and applications of nano fibers over the decade, the technology development for large-scale production of nano fibers has been hampered, which slows down the wide applications of nano fibers in practice. This special issue focuses on the recent progress in emerging nano fiber production techniques, such as needle less electro spinning, and novel properties and applications of nano fibers. It also covers unusual methods to process natural materials into nano fibrous materials. The special issue consists of four review articles and eighteen research papers. One review paper presents an overview of the recent developments in needle less electro spinning and the influences of needle less spinnerets on electro spinning process, nano fiber quality and productivity. The review also points out the challenges remaining for further research in this area. Other three reviews separately summarize the preparation, characterization and applications of ZnO nano wires and the applications of carbon nano fibers for neural electrical/chemical interfaces and for cement reinforcement. The research articles report new results of needle less electro spinning techniques, and novel methods to make bi component nano fibers, porous nano fibers, nano fiber hydrogel and chitin nan ofibrils. As Guest Editors for this special issue, we are pleased to see the progress in the applications of nano fibers, especially for sound absorption and for protective clothing, as well as the antibacterial properties of titanate nano fibers. We hope this special issue will promote further development of large-scale economically feasible nano fiber-making technologies, and also contribute to the wide use of nano fibers. We also hope that the articles collected in this special issue are well-received by the reader.

Phonon-magnon resonant processes with relevance to acoustic spin pumping

KAUST Repository

Deymier, P. A.

2014-12-23

The recently described phenomenon of resonant acoustic spin pumping is due to resonant coupling between an incident elastic wave and spin waves in a ferromagnetic medium. A classical one-dimensional discrete model of a ferromagnet with two forms of magnetoelastic coupling is treated to shed light on the conditions for resonance between phonons and magnons. Nonlinear phonon-magnon interactions in the case of a coupling restricted to diagonal terms in the components of the spin degrees of freedom are analyzed within the framework of the multiple timescale perturbation theory. In that case, one-phonon-two-magnon resonances are the dominant mechanism for pumping. The effect of coupling on the dispersion relations depends on the square of the amplitude of the phonon and magnon excitations. A straightforward analysis of a linear phonon-magnon interaction in the case of a magnetoelastic coupling restricted to off-diagonal terms in the components of the spins shows a one-phonon to one-magnon resonance as the pumping mechanism. The resonant dispersion relations are independent of the amplitude of the waves. In both cases, when an elastic wave with a fixed frequency is used to stimulate magnons, application of an external magnetic field can be used to approach resonant conditions. Both resonance conditions exhibit the same type of dependency on the strength of an applied magnetic field.

Electro and gamma nuclear physics in Geant4

CERN Document Server

Wellisch, J P; Degtyarenko, P V

2003-01-01

Adequate description of electro and gamma nuclear physics is of utmost importance in studies of electron beam-dumps and intense electron beam accelerators. I also is mandatory to describe neutron backgrounds and activation in linear colliders. This physics was elaborated in Geant4 over the last year, and now entered into the stage of practical application. In the {\\sc Geant4} Photo-nuclear data base there are at present about 50 nuclei for which the Photo-nuclear absorption cross sections have been measured. Of these, data on 14 nuclei are used to parametrize the gamma nuclear reaction cross-section The resulting cross section is a complex, factorized function of $A$ and $e = log(E_\\gamma)$, where $E_\\gamma$ is the energy of the incident photon. Electro-nuclear reactions are so closely connected with Photo-nuclear reactions that sometimes they are often called ``Photo-nuclear''. The one-photon exchange mechanism dominates in Electro-nuclear reactions, and the electron can be substituted by a flux of photons. ...

Validating and improving the correction of ocular artifacts in electro-encephalography

NARCIS (Netherlands)

Kierkels, J.J.M.

2007-01-01

For modern applications of electro-encephalography, including brain computer interfaces and single-trial Event Related Potential detection, it is becoming increasingly important that artifacts are accurately removed from a recorded electro-encephalogram (EEG) without affecting the part of the EEG

An order-by-disorder process in the cyclic phase of spin-2 condensate with a weak magnetic field

International Nuclear Information System (INIS)

Zheng, Gong-Ping; Xu, Lei-Kuan; Qin, Shuai-Feng; Jian, Wen-Tian; Liang, J.-Q.

2013-01-01

We present in this paper a model study on the “order-by-disorder” process in the cyclic phase of spin-2 condensate, which forms a family of incommensurable, spiral degenerate ground states. On the basis of the ordering mechanism of entropic splitting, it is demonstrated that the energy corrections resulting from quantum fluctuations of disorder lift the accidental degeneracy of the cyclic configurations and thus lead to an eventual spiral order called the cyclic order. The order-by-disorder phenomenon is then realized even if the magnetic field exists. Finally, we show that our theoretic observations can be verified experimentally by direct detection of the cyclic order in the 87 Rb condensate of a spin-2 manifold with a weak magnetic field. -- Highlights: •A model for the order-by-disorder process in the cyclic phase of spin-2 condensate is presented. •The second-order quantum fluctuations of the mean-field states are studied. •The energy corrections lift the accidental degeneracy of the cyclic configurations. •The order-by-disorder phenomenon is realized even if a magnetic field exists. •The theoretic observations can be verified experimentally for 87 Rb condensate

Building electro-optical systems making it all work

CERN Document Server

Hobbs, Philip C D

2009-01-01

Praise for the First Edition ""Now a new laboratory bible for optics researchers has joined the list: it is Phil Hobbs's Building Electro-Optical Systems: Making It All Work.""-Tony Siegman, Optics & Photonics News Building a modern electro-optical instrument may be the most interdisciplinary job in all of engineering. Be it a DVD player or a laboratory one-off, it involves physics, electrical engineering, optical engineering, and computer science interacting in complex ways. This book will help all kinds of technical people sort through the complexit

Recent progress in GeSi electro-absorption modulators

International Nuclear Information System (INIS)

Chaisakul, Papichaya; Marris-Morini, Delphine; Rouifed, Mohamed-Said; Coudevylle, Jean-René; Roux, Xavier Le; Edmond, Samson; Vivien, Laurent; Frigerio, Jacopo; Chrastina, Daniel; Isella, Giovanni

2014-01-01

Electro-absorption from GeSi heterostructures is receiving growing attention as a high performance optical modulator for short distance optical interconnects. Ge incorporation with Si allows strong modulation mechanism using the Franz–Keldysh effect and the quantum-confined Stark effect from bulk and quantum well structures at telecommunication wavelengths. In this review, we discuss the current state of knowledge and the on-going challenges concerning the development of high performance GeSi electro-absorption modulators. We also provide feasible future prospects concerning this research topic. (review)

Spin Polarization Oscillations without Spin Precession: Spin-Orbit Entangled Resonances in Quasi-One-Dimensional Spin Transport

Directory of Open Access Journals (Sweden)

D. H. Berman

2014-03-01

Full Text Available Resonant behavior involving spin-orbit entangled states occurs for spin transport along a narrow channel defined in a two-dimensional electron gas, including an apparent rapid relaxation of the spin polarization for special values of the channel width and applied magnetic field (so-called ballistic spin resonance. A fully quantum-mechanical theory for transport using multiple subbands of the one-dimensional system provides the dependence of the spin density on the applied magnetic field and channel width and position along the channel. We show how the spatially nonoscillating part of the spin density vanishes when the Zeeman energy matches the subband energy splittings. The resonance phenomenon persists in the presence of disorder.

Nonlocal magnon spin transport in yttrium iron garnet with tantalum and platinum spin injection/detection electrodes

Science.gov (United States)

Liu, J.; Cornelissen, L. J.; Shan, J.; van Wees, B. J.; Kuschel, T.

2018-06-01

We study the magnon spin transport in the magnetic insulator yttrium iron garnet (YIG) in a nonlocal experiment and compare the magnon spin excitation and detection for the heavy metal paramagnetic electrodes platinum (Pt|YIG|Pt) and tantalum (Ta|YIG|Ta). The electrical injection and detection processes rely on the (inverse) spin Hall effect in the heavy metals and the conversion between the electron spin and magnon spin at the heavy metal|YIG interface. Pt and Ta possess opposite signs of the spin Hall angle. Furthermore, their heterostructures with YIG have different interface properties, i.e. spin mixing conductances. By varying the distance between injector and detector, the magnon spin transport is studied. Using a circuit model based on the diffusion-relaxation transport theory, a similar magnon relaxation length of  ∼10 μm was extracted from both Pt and Ta devices. By changing the injector and detector material from Pt to Ta, the influence of interface properties on the magnon spin transport has been observed. For Ta devices on YIG the spin mixing conductance is reduced compared with Pt devices, which is quantitatively consistent when comparing the dependence of the nonlocal signal on the injector-detector distance with the prediction from the circuit model.

Effect of spin rotation coupling on spin transport

International Nuclear Information System (INIS)

Chowdhury, Debashree; Basu, B.

2013-01-01

We have studied the spin rotation coupling (SRC) as an ingredient to explain different spin-related issues. This special kind of coupling can play the role of a Dresselhaus like coupling in certain conditions. Consequently, one can control the spin splitting, induced by the Dresselhaus like term, which is unusual in a semiconductor heterostructure. Within this framework, we also study the renormalization of the spin-dependent electric field and spin current due to the k → ⋅p → perturbation, by taking into account the interband mixing in the rotating system. In this paper we predict the enhancement of the spin-dependent electric field resulting from the renormalized spin rotation coupling. The renormalization factor of the spin electric field is different from that of the SRC or Zeeman coupling. The effect of renormalized SRC on spin current and Berry curvature is also studied. Interestingly, in the presence of this SRC-induced SOC it is possible to describe spin splitting as well as spin galvanic effect in semiconductors. -- Highlights: •Studied effect of spin rotation coupling on the spin electric field, spin current and Berry curvature. •In the k → ⋅p → framework we study the renormalization of spin electric field and spin current. •For an inertial system we have discussed the spin splitting. •Expression for the Berry phase in the inertial system is discussed. •The inertial spin galvanic effect is studied

Effect of spin rotation coupling on spin transport

Energy Technology Data Exchange (ETDEWEB)

Chowdhury, Debashree, E-mail: debashreephys@gmail.com; Basu, B., E-mail: sribbasu@gmail.com

2013-12-15

We have studied the spin rotation coupling (SRC) as an ingredient to explain different spin-related issues. This special kind of coupling can play the role of a Dresselhaus like coupling in certain conditions. Consequently, one can control the spin splitting, induced by the Dresselhaus like term, which is unusual in a semiconductor heterostructure. Within this framework, we also study the renormalization of the spin-dependent electric field and spin current due to the k{sup →}⋅p{sup →} perturbation, by taking into account the interband mixing in the rotating system. In this paper we predict the enhancement of the spin-dependent electric field resulting from the renormalized spin rotation coupling. The renormalization factor of the spin electric field is different from that of the SRC or Zeeman coupling. The effect of renormalized SRC on spin current and Berry curvature is also studied. Interestingly, in the presence of this SRC-induced SOC it is possible to describe spin splitting as well as spin galvanic effect in semiconductors. -- Highlights: •Studied effect of spin rotation coupling on the spin electric field, spin current and Berry curvature. •In the k{sup →}⋅p{sup →} framework we study the renormalization of spin electric field and spin current. •For an inertial system we have discussed the spin splitting. •Expression for the Berry phase in the inertial system is discussed. •The inertial spin galvanic effect is studied.

Precise real-time polarization measurement of terahertz electromagnetic waves by a spinning electro-optic sensor.

Science.gov (United States)

Yasumatsu, Naoya; Watanabe, Shinichi

2012-02-01

We propose and develop a method to quickly and precisely determine the polarization direction of coherent terahertz electromagnetic waves generated by femtosecond laser pulses. The measurement system consists of a conventional terahertz time-domain spectroscopy system with the electro-optic (EO) sampling method, but we add a new functionality in the EO crystal which is continuously rotating with the angular frequency ω. We find a simple yet useful formulation of the EO signal as a function of the crystal orientation, which enables a lock-in-like detection of both the electric-field amplitude and the absolute polarization direction of the terahertz waves with respect to the probe laser pulse polarization direction at the same time. The single measurement finishes around two periods of the crystal rotations (∼21 ms), and we experimentally prove that the accuracy of the polarization measurement does not suffer from the long-term amplitude fluctuation of the terahertz pulses. Distribution of the measured polarization directions by repeating the measurements is excellently fitted by a gaussian distribution function with a standard deviation of σ = 0.56°. The developed technique is useful for the fast direct determination of the polarization state of the terahertz electromagnetic waves for polarization imaging applications as well as the precise terahertz Faraday or Kerr rotation spectroscopy.

Electro Thermal Chemical Gun Technology Study

National Research Council Canada - National Science Library

Diamond, P

1999-01-01

.... Michael Stroscio. Electro Thermal Chemical (ETC) gun technology refers to the use of plasma devices in place of traditional chemical ignitors to initiate the burning of high energy propellants in a controlled manner...

Hybrid electro-optics and chipscale integration of electronics and photonics

Science.gov (United States)

Dalton, L. R.; Robinson, B. H.; Elder, D. L.; Tillack, A. F.; Johnson, L. E.

2017-08-01

Taken together, theory-guided nano-engineering of organic electro-optic materials and hybrid device architectures have permitted dramatic improvement of the performance of electro-optic devices. For example, the voltage-length product has been improved by nearly a factor of 104 , bandwidths have been extended to nearly 200 GHz, device footprints reduced to less than 200 μm2 , and femtojoule energy efficiency achieved. This presentation discusses the utilization of new coarse-grained theoretical methods and advanced quantum mechanical methods to quantitatively simulate the physical properties of new classes of organic electro-optic materials and to evaluate their performance in nanoscopic device architectures, accounting for the effect on chromophore ordering at interfaces in nanoscopic waveguides.

Influence of pulsed electric field on defectoscopic characteristics of electro- x-ray radiography

International Nuclear Information System (INIS)

Gusev, E.A.; Lomonosov, V.V.; Sosnin, F.R.

1988-01-01

A new method to increase electric resistance of semiconductor plates in the process of electro-X-ray radiography, which is based on influence of a pulsed electric field on the plate semiconductor layer is suggested. The effect of a pulsed field with the intensity E=10 6 V/cm, frequency of 50 Hz and front length of 1 ns has increased electric resistance of the semiconductor layer and improved flaw detection in the process of electroradiography

Spin-Hall nano-oscillator: A micromagnetic study

Energy Technology Data Exchange (ETDEWEB)

Giordano, A.; Azzerboni, B.; Finocchio, G. [Department of Electronic Engineering, Industrial Chemistry and Engineering, University of Messina, C.da di Dio, I-98166 Messina (Italy); Carpentieri, M. [Department of Electrical and Information Engineering, Politecnico of Bari, via E. Orabona 4, I-70125 Bari (Italy); Laudani, A. [Department of Engineering, University of Roma Tre, via V. Volterra 62, I-00146 Roma (Italy); Gubbiotti, G. [Istituto Officina dei Materiali del CNR (CNR-IOM), Unità di Perugia c/o Dipartimento di Fisica e Geologia, Via A. Pascoli, 06123 Perugia (Italy)

2014-07-28

This Letter studies the dynamical behavior of spin-Hall nanoscillators from a micromagnetic point of view. The model parameters have been identified by reproducing recent experimental data quantitatively. Our results indicate that a strongly localized mode is observed for in-plane bias fields such as in the experiments, while predict the excitation of an asymmetric propagating mode for large enough out-of plane bias field similarly to what observed in spin-torque nanocontact oscillators. Our findings show that spin-Hall nanoscillators can find application as spin-wave emitters for magnonic applications where spin waves are used for transmission and processing information on nanoscale.

Recent Progress on Cellulose-Based Electro-Active Paper, Its Hybrid Nanocomposites and Applications.

Science.gov (United States)

Khan, Asif; Abas, Zafar; Kim, Heung Soo; Kim, Jaehwan

2016-07-26

We report on the recent progress and development of research into cellulose-based electro-active paper for bending actuators, bioelectronics devices, and electromechanical transducers. The cellulose electro-active paper is characterized in terms of its biodegradability, chirality, ample chemically modifying capacity, light weight, actuation capability, and ability to form hybrid nanocomposites. The mechanical, electrical, and chemical characterizations of the cellulose-based electro-active paper and its hybrid composites such as blends or coatings with synthetic polymers, biopolymers, carbon nanotubes, chitosan, and metal oxides, are explained. In addition, the integration of cellulose electro-active paper is highlighted to form various functional devices including but not limited to bending actuators, flexible speaker, strain sensors, energy harvesting transducers, biosensors, chemical sensors and transistors for electronic applications. The frontiers in cellulose paper devices are reviewed together with the strategies and perspectives of cellulose electro-active paper and cellulose nanocomposite research and applications.

Recent Progress on Cellulose-Based Electro-Active Paper, Its Hybrid Nanocomposites and Applications

Directory of Open Access Journals (Sweden)

Asif Khan

2016-07-01

Full Text Available We report on the recent progress and development of research into cellulose-based electro-active paper for bending actuators, bioelectronics devices, and electromechanical transducers. The cellulose electro-active paper is characterized in terms of its biodegradability, chirality, ample chemically modifying capacity, light weight, actuation capability, and ability to form hybrid nanocomposites. The mechanical, electrical, and chemical characterizations of the cellulose-based electro-active paper and its hybrid composites such as blends or coatings with synthetic polymers, biopolymers, carbon nanotubes, chitosan, and metal oxides, are explained. In addition, the integration of cellulose electro-active paper is highlighted to form various functional devices including but not limited to bending actuators, flexible speaker, strain sensors, energy harvesting transducers, biosensors, chemical sensors and transistors for electronic applications. The frontiers in cellulose paper devices are reviewed together with the strategies and perspectives of cellulose electro-active paper and cellulose nanocomposite research and applications.

Pulsed-diode-pumped, all-solid-state, electro-optically controlled picosecond Nd:YAG lasers

International Nuclear Information System (INIS)

Gorbunkov, Mikhail V; Shabalin, Yu V; Konyashkin, A V; Kostryukov, P V; Olenin, A N; Tunkin, V G; Morozov, V B; Rusov, V A; Telegin, L S; Yakovlev, D V

2005-01-01

The results of the development of repetitively pulsed, diode-pumped, electro-optically controlled picosecond Nd:YAG lasers of two designs are presented. The first design uses the active-passive mode locking with electro-optical lasing control and semiconductor saturable absorber mirrors (SESAM). This design allows the generation of 15-50-ps pulses with an energy up to 0.5 mJ and a maximum pulse repetition rate of 100 Hz. The laser of the second design generates 30-ps pulses due to combination of positive and negative electro-optical feedback and the control of the electro-optical modulator by the photocurrent of high-speed semiconductor structures. (active media. lasers)

PtRu/C and PtRuBi/C electrocatalysts prepared by two different methodologies of borohydride reduction process for ethanol electro-oxidation

Energy Technology Data Exchange (ETDEWEB)

Brandalise, Michele; Tusi, Marcelo Marques; Piasentin, Ricardo Marcelo; Correa, Olandir Vercino; Linardi, Marcelo; Spinace, Estevam Vitorio; Oliveira Neto, Almir, E-mail: brandalise@usp.br, E-mail: mmtusi@usp.br, E-mail: rmpiasen@ipen.br, E-mail: ovcorrea@ipen.br, E-mail: mlinardi@ipen.br, E-mail: espinace@ipen.br, E-mail: aolivei@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2009-07-01

PtRu/C (50:50) and PtRuBi/C (50:40:10) electrocatalysts were prepared by borohydride reduction using H{sub 2}PtCl{sub 6.6}H{sub 2}O, RuCl{sub 3.x}H{sub 2}O and Bi(NO{sub 3}){sub 3.5}H{sub 2}O as metals sources and Vulcan XC72 as support. The borohydride solution was added in two different ways: drop by drop and rapid addition of all the solution. The obtained electrocatalysts were characterized by EDX, XRD and cyclic voltammetry. The electro-oxidation of ethanol was studied by cyclic voltammetry and chronoamperometry at room temperature and on a single cell of a direct ethanol fuel cell (DEFC) at 100 deg C. PtRuBi/C electrocatalysts showed superior performance for ethanol electro-oxidation than PtRu/C electrocatalysts prepared in a similar way. However, PtRuBi/C electrocatalyst prepared by rapid addition of the borohydride solution showed superior performance for ethanol electro oxidation at room temperature, while PtRuBi/C electrocatalyst prepared by addition drop by drop of borohydride solution showed superior performance on DEFC at 100 deg C. (author)

PtRu/C and PtRuBi/C electrocatalysts prepared by two different methodologies of borohydride reduction process for ethanol electro-oxidation

International Nuclear Information System (INIS)

Brandalise, Michele; Tusi, Marcelo Marques; Piasentin, Ricardo Marcelo; Correa, Olandir Vercino; Linardi, Marcelo; Spinace, Estevam Vitorio; Oliveira Neto, Almir

2009-01-01

PtRu/C (50:50) and PtRuBi/C (50:40:10) electrocatalysts were prepared by borohydride reduction using H 2 PtCl 6.6 H 2 O, RuCl 3.x H 2 O and Bi(NO 3 ) 3.5 H 2 O as metals sources and Vulcan XC72 as support. The borohydride solution was added in two different ways: drop by drop and rapid addition of all the solution. The obtained electrocatalysts were characterized by EDX, XRD and cyclic voltammetry. The electro-oxidation of ethanol was studied by cyclic voltammetry and chronoamperometry at room temperature and on a single cell of a direct ethanol fuel cell (DEFC) at 100 deg C. PtRuBi/C electrocatalysts showed superior performance for ethanol electro-oxidation than PtRu/C electrocatalysts prepared in a similar way. However, PtRuBi/C electrocatalyst prepared by rapid addition of the borohydride solution showed superior performance for ethanol electro oxidation at room temperature, while PtRuBi/C electrocatalyst prepared by addition drop by drop of borohydride solution showed superior performance on DEFC at 100 deg C. (author)

Recent Progress on Cellulose-Based Electro-Active Paper, Its Hybrid Nanocomposites and Applications

OpenAIRE

Asif Khan; Zafar Abas; Heung Soo Kim; Jaehwan Kim

2016-01-01

We report on the recent progress and development of research into cellulose-based electro-active paper for bending actuators, bioelectronics devices, and electromechanical transducers. The cellulose electro-active paper is characterized in terms of its biodegradability, chirality, ample chemically modifying capacity, light weight, actuation capability, and ability to form hybrid nanocomposites. The mechanical, electrical, and chemical characterizations of the cellulose-based electro-active pa...

ElectroGraph - Graphene-based electrodes for application in supercapacitors

OpenAIRE

Kosidlo, Urszula

2012-01-01

The ElectroGraph project follows an integrated, technology driven approach in development of novel materials and components for realization of optimized supercapacitors. These are considered one of the newest innovations in the field of electrical energy storage. To design a supercapacitor with high energy and power density, it is crucial to select the correct electrode materials and the most suitable electrolytes. That is why ElectroGraph project focuses on development and use of graphene as...

Treatment of radioactive metallic waste by the electro-slag melting method

International Nuclear Information System (INIS)

Ochiai, Atsuhiro; Nagura, Kanetake; Noura, Tsuyoshi

1983-01-01

The applicability of the electro-slag melting method for treating plutonuim contaminated metallic waste was studied. A 100kg test furnace was built and simulated metallic waste was melted and solidified in this furnace. Waste volume was reduced to 1/25 with a decontamination factor of 25 and the slag and the copper mold are repeatedly usable. The process is expected to be employed in the project of PWTF (Plutonium contaminated Wate Treatment Facilities). (author)

Pyroelectrically Induced Pyro-Electro-Chemical Catalytic Activity of BaTiO3 Nanofibers under Room-Temperature Cold–Hot Cycle Excitations

OpenAIRE

Yuntao Xia; Yanmin Jia; Weiqi Qian; Xiaoli Xu; Zheng Wu; Zichen Han; Yuanting Hong; Huilin You; Muhammad Ismail; Ge Bai; Liwei Wang

2017-01-01

A pyro-electro-chemical catalytic dye decomposition using lead-free BaTiO3 nanofibers was realized under room-temperature cold–hot cycle excitation (30–47 °C) with a high Rhodamine B (RhB) decomposition efficiency ~99%, which should be ascribed to the product of pyro-electric effect and electrochemical redox reaction. Furthermore, the existence of intermediate product of hydroxyl radical in pyro-electro-chemical catalytic process was also observed. There is no significant decrease in pyro-ele...

Dual descriptors within the framework of spin-polarized density functional theory.

Science.gov (United States)

Chamorro, E; Pérez, P; Duque, M; De Proft, F; Geerlings, P

2008-08-14

Spin-polarized density functional theory (SP-DFT) allows both the analysis of charge-transfer (e.g., electrophilic and nucleophilic reactivity) and of spin-polarization processes (e.g., photophysical changes arising from electron transitions). In analogy with the dual descriptor introduced by Morell et al. [J. Phys. Chem. A 109, 205 (2005)], we introduce new dual descriptors intended to simultaneously give information of the molecular regions where the spin-polarization process linking states of different multiplicity will drive electron density and spin density changes. The electronic charge and spin rearrangement in the spin forbidden radiative transitions S(0)-->T(n,pi(*)) and S(0)-->T(pi,pi(*)) in formaldehyde and ethylene, respectively, have been used as benchmark examples illustrating the usefulness of the new spin-polarization dual descriptors. These quantities indicate those regions where spin-orbit coupling effects are at work in such processes. Additionally, the qualitative relationship between the topology of the spin-polarization dual descriptors and the vertical singlet triplet energy gap in simple substituted carbene series has been also discussed. It is shown that the electron density and spin density rearrangements arise in agreement with spectroscopic experimental evidence and other theoretical results on the selected target systems.

High-speed micro-electro-discharge machining.

Energy Technology Data Exchange (ETDEWEB)

Chandrasekar, Srinivasan Dr. (.School of Industrial Engineering, West Lafayette, IN); Moylan, Shawn P. (School of Industrial Engineering, West Lafayette, IN); Benavides, Gilbert Lawrence

2005-09-01

When two electrodes are in close proximity in a dielectric liquid, application of a voltage pulse can produce a spark discharge between them, resulting in a small amount of material removal from both electrodes. Pulsed application of the voltage at discharge energies in the range of micro-Joules results in the continuous material removal process known as micro-electro-discharge machining (micro-EDM). Spark erosion by micro-EDM provides significant opportunities for producing small features and micro-components such as nozzle holes, slots, shafts and gears in virtually any conductive material. If the speed and precision of micro-EDM processes can be significantly enhanced, then they have the potential to be used for a wide variety of micro-machining applications including fabrication of microelectromechanical system (MEMS) components. Toward this end, a better understanding of the impacts the various machining parameters have on material removal has been established through a single discharge study of micro-EDM and a parametric study of small hole making by micro-EDM. The main avenues for improving the speed and efficiency of the micro-EDM process are in the areas of more controlled pulse generation in the power supply and more controlled positioning of the tool electrode during the machining process. Further investigation of the micro-EDM process in three dimensions leads to important design rules, specifically the smallest feature size attainable by the process.

Information transmission and control in a chaotically kicked spin chain

International Nuclear Information System (INIS)

Aubourg, Lucile; Viennot, David

2016-01-01

We study spin chains submitted to disturbed kick trains described by classical dynamical processes. The spin chains are coupled by Heisenberg and Ising-Z models. We consider chaotic processes by using the kick irregularity in the multipartite system (the spin chain). We show that both couplings transmit the chaos disorder differently along the spin chain but conserve the horizon of coherence (when the disorder into the kick bath is transmitted to the spin chain). An example of information transmission between the spins of the chain coupled by a Heisenberg interaction shows the interest of the horizon of coherence. The use of some chosen stationary kicks disturbed by a chaotic environment makes it possible to modify the information transmission between the spins and to perform a free control during the horizon of coherence. (paper)

Spin content of constituent quarks and one-spin asymmetries in inclusive processes

International Nuclear Information System (INIS)

Troshin, S.M.; Tyurin, N.E.

1995-01-01

A mechanism for one-spin asymmetries observed in inclusive hadron production is considered. The main role belongs to the orbital angular momentum of the quark-antiquark cloud in the internal structure of constituent quarks. The origin of the asymmetries in pion production is a result of retaining this internal angular orbital momentum by the perturbative phase of QCD under transition from the non-perturbative phase is proved. The non-perturbative hadron structure is based on the results of chiral quark models. 33 refs.; 8 figs

Ultrafast optical control of individual quantum dot spin qubits.

Science.gov (United States)

De Greve, Kristiaan; Press, David; McMahon, Peter L; Yamamoto, Yoshihisa

2013-09-01

Single spins in semiconductor quantum dots form a promising platform for solid-state quantum information processing. The spin-up and spin-down states of a single electron or hole, trapped inside a quantum dot, can represent a single qubit with a reasonably long decoherence time. The spin qubit can be optically coupled to excited (charged exciton) states that are also trapped in the quantum dot, which provides a mechanism to quickly initialize, manipulate and measure the spin state with optical pulses, and to interface between a stationary matter qubit and a 'flying' photonic qubit for quantum communication and distributed quantum information processing. The interaction of the spin qubit with light may be enhanced by placing the quantum dot inside a monolithic microcavity. An entire system, consisting of a two-dimensional array of quantum dots and a planar microcavity, may plausibly be constructed by modern semiconductor nano-fabrication technology and could offer a path toward chip-sized scalable quantum repeaters and quantum computers. This article reviews the recent experimental developments in optical control of single quantum dot spins for quantum information processing. We highlight demonstrations of a complete set of all-optical single-qubit operations on a single quantum dot spin: initialization, an arbitrary SU(2) gate, and measurement. We review the decoherence and dephasing mechanisms due to hyperfine interaction with the nuclear-spin bath, and show how the single-qubit operations can be combined to perform spin echo sequences that extend the qubit decoherence from a few nanoseconds to several microseconds, more than 5 orders of magnitude longer than the single-qubit gate time. Two-qubit coupling is discussed, both within a single chip by means of exchange coupling of nearby spins and optically induced geometric phases, as well as over longer-distances. Long-distance spin-spin entanglement can be generated if each spin can emit a photon that is entangled

Field-induced negative differential spin lifetime in silicon.

Science.gov (United States)

Li, Jing; Qing, Lan; Dery, Hanan; Appelbaum, Ian

2012-04-13

We show that the electric-field-induced thermal asymmetry between the electron and lattice systems in pure silicon substantially impacts the identity of the dominant spin relaxation mechanism. Comparison of empirical results from long-distance spin transport devices with detailed Monte Carlo simulations confirms a strong spin depolarization beyond what is expected from the standard Elliott-Yafet theory even at low temperatures. The enhanced spin-flip mechanism is attributed to phonon emission processes during which electrons are scattered between conduction band valleys that reside on different crystal axes. This leads to anomalous behavior, where (beyond a critical field) reduction of the transit time between spin-injector and spin-detector is accompanied by a counterintuitive reduction in spin polarization and an apparent negative spin lifetime.

Single transverse-spin asymmetric in hardronic collisions

International Nuclear Information System (INIS)

Qiu, J.

1995-01-01

We provide a consistent treatment of single transverse-spin asymmetriesin hadronic collisions in terms of the generalized factorization theorem in perturbative QCD. The asymmetries in different physical processes, such as direct photon, single particle production, can be expressed in terms of a calculable partonic hard-part convoluted with universal three-parton correlation functions. We show that the observed single transverse- spin asymmtries in hadronic pion production can be understood, and used to extract the information on these correlation functions. With these correlation functions, predictions on single spin asymmetries in other processes can be made, and consequently, the theory can be tested

Elementary spin excitations in ultrathin itinerant magnets

Energy Technology Data Exchange (ETDEWEB)

Zakeri, Khalil, E-mail: zakeri@mpi-halle.de

2014-12-10

Elementary spin excitations (magnons) play a fundamental role in condensed matter physics, since many phenomena e.g. magnetic ordering, electrical (as well as heat) transport properties, ultrafast magnetization processes, and most importantly electron/spin dynamics can only be understood when these quasi-particles are taken into consideration. In addition to their fundamental importance, magnons may also be used for information processing in modern spintronics. Here the concept of spin excitations in ultrathin itinerant magnets is discussed and reviewed. Starting with a historical introduction, different classes of magnons are introduced. Different theoretical treatments of spin excitations in solids are outlined. Interaction of spin-polarized electrons with a magnetic surface is discussed. It is shown that, based on the quantum mechanical conservation rules, a magnon can only be excited when a minority electron is injected into the system. While the magnon creation process is forbidden by majority electrons, the magnon annihilation process is allowed instead. These fundamental quantum mechanical selection rules, together with the strong interaction of electrons with matter, make the spin-polarized electron spectroscopies as appropriate tools to excite and probe the elementary spin excitations in low-dimensional magnets e.g ultrathin films and nanostructures. The focus is put on the experimental results obtained by spin-polarized electron energy loss spectroscopy and spin-polarized inelastic tunneling spectroscopy. The magnon dispersion relation, lifetime, group and phase velocity measured using these approaches in various ultrathin magnets are discussed in detail. The differences and similarities with respect to the bulk excitations are addressed. The role of the temperature, atomic structure, number of atomic layers, lattice strain, electronic complexes and hybridization at the interfaces are outlined. A possibility of simultaneous probing of magnons and phonons

Gradient effects in a new class of electro-elastic bodies

Science.gov (United States)

Arvanitakis, Antonios

2018-06-01

Continuum theories for electro-elastic solids suggest the development of electric field or polarization-based models. Advanced versions of these models are the so-called gradient models, i.e., polarization gradient and electric field gradient models, which prove to be more than capable of explaining the behavior of a continuum in a wider range of length scales. In this work, implicit constitutive relations for electro-elastic bodies are considered with the introduction of polarization and electric field gradient effects. In this sense, the new class of electro-elastic bodies extends even further to account for nonlocality in constitutive equations, besides strain-limiting behavior and polarization saturation for large values of stresses and electric field, respectively. Nonlocality in constitutive equations is essential in modeling various phenomena.

The Study on the Performance of Carbon Supported PtSnM (M = W, Pd, and Ni) Ternary Electro-Catalysts for Ethanol Electro-Oxidation Reaction.

Science.gov (United States)

Noh, Chang Soo; Heo, Dong Hyun; Lee, Ki Rak; Jeon, Min Ku; Sohn, Jung Min

2016-05-01