EC System Research Articles

Demonstration of synchronous control of EC TL switch and gyrotron for ITER EC system

The ITER EC system includes both an equatorial port launcher and upper port launchers as RF power injection devices, The waveguide switch in the transmission line (TL) is used to select the operating launcher. Its operation is required even during plasma operation, primarily for the mid-pulse switch operation. Changing the waveguide switch requires that the gyrotron stop RF power during the switch operation since the direction is changed by mechanical movement of the mirror position which takes a few seconds. Since the ITER EC system is based on a multi-subsystem concept, each subsystem has its own subsystem control unit (SCU). The EC main controller supervises all subsystem controllers. Hence, cooperative operation requires the sharing of the information of both RF power status and switch status between the gyrotron SCU and TL SCU via the main controller. Since the design of the inter-subsystem control scheme is a key issue for ITER EC system control, its evaluation is required. At QST, the gyrotron and ITER-relevant TL test stand were utilized for demonstration of mid-pulse switch operation. For this purpose, SCUs for each subsystem and the main controller were developed using the ITER-relevant control system. The operation of the mechanical switch during gyrotron pulse was demonstrated. During the 150s operation of the high power gyrotron at 400kW level, the waveguide switch in the TL was operated to change the direction of RF power. The time duration for the switch operation with inter-subsystem control scheme took 1.5s in total. The synchronizing of RF power suspend and resume with switch motion has therefore been realized, and RF power direction control during the gyrotron operation was successfully demonstrated.

EC power management in ITER for NTM control: the path from the commissioning phase to demonstration discharges

Time dependent simulations that evolve consistently the magnetic equilibrium and plasma pressure profiles and the width and frequency rotation of magnetic islands under the effect of the Electron Cyclotron feedback system are used to assess whether the control of NTMs on ITER is compatible with other simulataneous functionalities of the EC system, like core heating and current profile tailoring, or sawtooth control. Results indicate that the power needs for control can be reduced if the EC power is reserved and if pre-emptive control is used as opposed to an active search for an already developed island.

Analysis of silicon-based integrated photovoltaic–electrochemical hydrogen generation system under varying temperature and illumination

Last decade witnessed tremendous research and development in the area of photo-electrolytic hydrogen generation using chemically stable nanostructured photo-cathode/anode materials. Due to intimately coupled charge separation and photo-catalytic processes, it is very difficult to optimize individual components of such system leading to a very low demonstrated solar-to-fuel efficiency (SFE) of less than 1%. Recently there has been growing interest in an integrated photovoltaic–electrochemical (PV–EC) system based on GaAs solar cells with the demonstrated SFE of 24.5% under concentrated illumination condition. But a high cost of GaAs based solar cells and recent price drop of poly-crystalline silicon (pc-Si) solar cells motivated researchers to explore silicon based integrated PV–EC system. In this paper a theoretical framework is introduced to model silicon-based integrated PV–EC device. The theoretical framework is used to analyze the coupling and kinetic losses of a silicon solar cell based integrated PV–EC water splitting system under varying temperature and illumination. The kinetic loss occurs in the range of 19.1%–27.9% and coupling loss takes place in the range of 5.45%–6.74% with respect to varying illumination in the range of 20–100mW/cm2. Similarly, the effect of varying temperature has severe impact on the performance of the system, wherein the coupling loss occurs in the range of 0.84%–21.51% for the temperature variation from 25 to 50°C.

Efficient sonoelectrochemical decomposition of sulfamethoxazole adopting common Pt/graphite electrodes: The mechanism and favorable pathways

In this study, efficient degradation of sulfamethoxazole (SMX) with a high synergy factor of 14.7 was demonstrated in a sonoelectrochemical (US-EC) system adopting common Pt and graphite electrodes. It was found that the US-EC system could work effectively at broad pH range of 3–9, but would achieve good performances with appropriate electrochemical conditions at 20mA/cm2 and 0.1M Na2SO4. Both OH attacking and the anode oxidation would be responsible for the SMX degradation in the US-EC system, while the multiple promotional roles of US would be played homogenously and heterogeneously. US could not only effectively accelerate the decomposition of cathode-generated H2O2 into OH, but also lead to the enhancement in the heterogeneous reactions on the two electrodes, i.e. the cathode generation of H2O2 as well as the anode oxidation of SMX and H2O/OH−. Besides, the US-EC system would decompose SMX molecule via similar and simple pathways, by using either Na2SO4 or NaCl electrolytes. It was interesting to note that the US-EC system could successfully avoid the formation of complex chlorinated byproducts that detected in the referring EC system with NaCl. This finding would make the sonoelectrochemical processes favorable in treating practical wastewaters by alleviating the environmental impact of disinfection byproducts.

Influence of Swift Heavy O<sup>7+</sup> Ion Irradiation on Conductivity and Relaxation Dynamics of Two Different Blends of PVA:PEO:LiCF<sub>3</sub>SO<sub>3</sub>:EC System

In the present work, the variation in conductivity (σdc) and relaxation properties of two different blends i.e. Blend-1: [PVA(47.5):PEO(47.5):(LiCF3SO3)5:(EC)8] and Blend-2: [PVA(47):PEO(47):(LiCF3SO3)5:(EC)6] of PVA:PEO:LiCF3SO3:EC system, with respect to various fluences of swift heavy O7+ ion radiations ranging from 1x1011 to 3x1012 ions/cm2, is investigated in detail. Here, (i) the behavior of relaxation time (τ) calculated from M” vs. log f curves and (ii) the scaling of imaginary part of modulus (M”), is studied thoroughly for various fluences. The investigation thus, provides an insight regarding the effect of O7+ ion radiations on the relaxation dynamics of both the blends.

Epinephrine sensing at nanostructured Au electrode and determination its oxidative metabolism

Epinephrine (EP) is a neurotransmitter and hormone involved in an enormous number of processes in living organisms, however its highly active oxidation metabolites can cause hard damages and lead to serious health consequences. This paper described a relatively simple method of fabrication of Au nanotube array electrodes for electrochemical determination of EP, which could be easily transferred to non-laboratory conditions. On the basis of Tafel plot, some parameters of EP oxidation process like number of electrons involved in the rate-determining step (nα=2) and electron transfer coefficient (α=0.45) were evaluated for the studied electrode. The linear sweep voltammetry (LSV) revealed a very good linear response in the EP concentration range of 60–600μM EP, however to 1000μM its linearity differs insignificantly. Using differential pulse voltammetry (DPV), the calibration curve for EP determination is close to linear in the range of 10–150μM, but the detection limit of 2.8μM was evaluated for a lower concentration range 10–60μM. The proposed DPV method was successfully applied to the determination of EP in a pure, ascorbic acid containing and real samples. The DPV results were evaluated and compared with those obtained by the high-performance liquid chromatography (HPLC) method. Combining the ROXY™ EC System with mass spectrometry creates an analytical tool for oxidative products of EP and conjugation of EP reactive potential metabolites characterized for I and II stage of biotransformation. The presence of leucoadrenochrome-o-semiquinone radicals confirmed by mass spectrometry implies that the ECE (electron transfer-chemical reaction-electron transfer) mechanism of EP oxidation at the Au electrode is more feasible.

Effects of Core-Shell Interface Structures on ORR Activities: a Model Catalyst Study of Pt/Pd(111)

Introduction Pd@Pt core-shell catalyst is one of the promising cathode electrode materials for polymer electrolyte fuel cell (PEFC) from the view-points of a great potential to reduce Pt usage and to improve the oxygen reduction reaction (ORR) activity [1]. Recently, Daimon found that the activity of the Pd@Pt core-shell catalyst was markedly enhanced with dissolution of the core Pd atoms during applying the specific potential cycles [2]. Their results clearly indicate that comprehensive understandings not only of the Pt-shell surface but also of the interface between Pt-shell and Pd-core are crucial for developing highly-active and durable Pd@Pt core-shell catalysts. We have previously reported that electrocatalytic properties for various-thick Pt monolayers on Pd(111) model catalysts prepared by molecular beam epitaxy (MBE) [3]. In this study, we focus on the relation between ORR activities and atomic structures of near surface vicinity for the MBE-prepared Pt/Pd(111) bimetallic system. Experimental Sample fabrication processes of the Pt/Pd(111) were conducted in UHV. Pd(111) single crystal substrate was cleaned by Ar+ sputtering and subsequent annealing at 1073 K. 0.6 nm-thick Pt was deposited onto the cleaned Pd(111) by an electron-beam evaporation method at the substrate temperatures of 573 K and 673 K. The resulting surface structures were verified with reflection high-energy electron diffraction (RHEED), scanning tunneling microscope in UHV (UHV-STM), and low-energy ion scattering (LEIS). Then, the prepared Ptx nm/Pd(111) surfaces were transferred without being exposed to air to the EC system set in an N2-purged glove box. Cyclic voltammogram (CV) of the samples were recorded in N2-purged 0.1M HClO4, and, then, linear sweep voltammetry (LSV) was conducted by using a rotating electrode (RDE) method at 1600 rpm after saturating the solution with O2. The ORR activities were estimated by kinetic-controlled current density (j k) at 0.9V vs. RHE by using Koutecky-Levich equation. Results and Discussion Surface structures for the 573 K- and 673 K-fabricated Pt0.6 nm/Pd(111) are summarized in Figs.1 (a) and (b). The RHEED patterns (insets) and UHV-STM images clearly show that the Pt grow epitaxially on Pd(111) substrate (RHEED) and topmost surfaces are comprised of atomically flat terraces with ca. 50 nm width (UHV-STM), irrespective of the deposition temperatures. In contrast, the interface structures of the samples evaluated by LEIS (Fig. 1(c)) are clearly different: Pt compositions decays more rapidly with supporting time for the 573 K-prepared samples in comparison to that for the 673 K-sample. The results suggest that the interface between topmost Pt(111) epi-layers and substrate Pd(111) is sharper for the 573 K-prepared sample. Fig.1 (d) shows the CV curves for the 573 K- and 673 K-Pt0.6nm/Pd(111) (red and blue lines) and clean Pt(111) (black line). For both the Pt0.6 nm/Pd(111) surfaces, the hydrogen adsorption and desorption behaviors are almost same. In contrast, for the latter 673 K-surface, so-called butterfly peaks at 0.8 V that stem from OH adsorption and desorption shift to higher potentials by ca. 30 mV relative to clean Pt(111), although the positive shift of the former 573 K-surface is not clean. Fig.1 (e) presents the evaluated ORR activities for the 573 K- and 673 K-prepared samples, showing 6.2 and 3.6 fold higher activities than that of clean Pt(111). The results reveal that a steep interface between the Pt-shell and Pd-core is an essential for highly active Pd@Pt core-shell catalysts. Acknowledgement This study was supported by the New Energy and Industrial Technology Development Organization (NEDO) of Japan.

Progress of high power and long pulse ECRH system in EAST

In accordance with the long pulse objectives of the Experimental Advanced Superconducting Tokamak (EAST), an electron cyclotron resonance heating (ECRH) system with the feature of 4MW power for a pulse length up to 1000s at 140GHz, using second harmonic of the extraordinary mode (X2) is presently under construction at the institute of plasma physics, Chinese academy of sciences (ASIPP). The missions of the system are to provide central heating, current drive, plasma profile tailoring and control of magneto-hydrodynamic (MHD) instabilities. The continuous wave (CW) power is transmitted from the gyrotrons to EAST via low-loss evacuated waveguide transmission lines. Considering the diverse applications of the EC system, the front steering launcher is designed to inject four individually steered beams across nearly the entire plasma cross section. The beam's launch angles can be continuously varied with the optimized scanning range of over 30° in poloidal direction and ±25° in toroidal, as well as the polarization will be adjusted during the discharge by the orientations of a pair of polarizers in the transmission line to maintain the highest absorption for different operational scenarios. The commissioning of the first 2MW system will be commenced in the end of 2014.

Progress in the ITER electron cyclotron heating and current drive system design

An electron cyclotron system is one of the four auxiliary plasma heating systems to be installed on the ITER tokamak. The ITER EC system consists of 24 gyrotrons with associated 12 high voltage power supplies, a set of evacuated transmission lines and two types of launchers. The whole system is designed to inject 20MW of microwave power at 170GHz into the plasma. The primary functions of the system include plasma start-up, central heating and current drive, and magneto-hydrodynamic instabilities control. The design takes present day technology and extends towards high power CW operation, which represents a large step forward as compared to the present state of the art. The ITER EC system will be a stepping stone to future EC systems for DEMO and beyond.The EC system is faced with significant challenges, which not only includes an advanced microwave system for plasma heating and current drive applications but also has to comply with stringent requirements associated with nuclear safety as ITER became the first fusion device licensed as basic nuclear installations as of 9 November 2012.Since conceptual design of the EC system established in 2007, the EC system has progressed to a preliminary design stage in 2012, and is now moving forward towards a final design. The majority of the subsystems have completed the detailed design and now advancing towards the final design completion.

Power measurement system of ECRH on HL-2A

Electron Cyclotron Resonance Heating (ECRH) is one of the main auxiliary heating systems for HL-2A tokamak. The ECRH system with total output power 5MW has been equipped on HL-2A which include 6 sets of 0.5MW/1.0s at a frequency of 68GHz and 2 sets of 1MW/3s at a frequency of 140GHz. The power is one of important parameters in ECRH system. In this paper, the method for measuring the power of ECRH system on HL-2A is introduced which include calorimetric techniques and directional coupler. Calorimetric techniques is an existing method, which is used successfully in ECRH commissioning and experiment, and the transmission efficiency of ECRH system is achieved by measuring the absorbed microwave power in the Match Optical Unit (MOU), gyrotron output window and tours window of the EC system use this method. Now base on the theory of electromagnetic coupling through apertures, directional couplers are being designed, which is a new way for us.

High power ECRH and ECCD in moderately collisional ASDEX Upgrade Hmodes and status of EC system upgrade

This contribution deals with H-modes with significant heat exchange between electrons and ions, but which can still show large differences between electron and ion-temperatures especially inside half minor radius. These conditions are referred to as moderately collisional. A systematic study shows that an increasing fraction of electron heating increases the transport in the ion channel mainly due to the dependence of the ITG dominated ion transport on the ratio Te/Ti in agreement with modeling. The rotational shear in the plasmas under study was so small that it hardly influences ITG stability, such that variations of the rotation profile due to a change of the heating method were of minor importance. These findings connect to studies of advanced tokamak scenarios using ECCD as a tool to modify the q-profile. The electron heating connected to the ECCD tends to increase the transport in the ion channel quite in contrast to the goal to operate at reduced current but with increased confinement. The confinement only increases as the fraction of ion heating is increased by adding more NBI. An ITER case was modeled as well. Due to the larger value ofei��E the ratio Te/Ti is only moderately reduced even with strong electron heating and the confinement reduction is small even for the hypothetic case of using only ECRH as additional heating. Finally the paper discusses the ongoing upgrade of the AUG ECRH-system.

Involvement of the endocannabinoid system in attentional modulation of nociceptive behaviour in rats.

Distraction is used clinically to relieve and manage pain. It is hypothesized that pain demands attention and that exposure to another attention-demanding stimulus causes withdrawal of attention away from painful stimuli, thereby reducing perceived pain. We have recently developed a rat model that provides an opportunity to investigate the neurobiological mechanisms mediating distraction-induced analgesia, as these mechanisms are, at present, poorly understood. Given the well-described role of the endogenous cannabinoid (endocannabinoid; EC) system in the modulation of pain and attentional processing, the present study investigated its role in distraction-induced antinociception in rats. Animals received the CB1 receptor antagonist/inverse agonist, rimonabant or vehicle intraperitoneally, 30 min prior to behavioural evaluation. Formalin-evoked nociceptive behaviour was measured in the presence or absence of a novel-object distractor. Liquid chromatography-tandem mass spectrometry was used to determine the levels of the endogenous cannabinoids anandamide and 2-arachidonoylglycerol (2-AG) in the ventral hippocampus (vHip). Exposure to a novel object distractor significantly reduced formalin-evoked nociceptive behaviour. The novel object-induced reduction in nociceptive behaviour was attenuated by rimonabant. Novel object exposure was also associated with increased tissue levels of anandamide and 2-AG in the vHip. These data suggest that the reduction in formalin-evoked nociceptive behaviour that occurs as a result of exposure to a novel object may be mediated by engagement of the EC system, in particular in the vHip. The results provide evidence that the EC system may be an important neural substrate subserving attentional modulation of pain.

P2 - In vitro glycation and glycoxidation of phosphatidylethanolamines

Formation and accumulation of advanced glycation end products (AGEs) appear to correlate with many human diseases, such as atherosclerosis and inflammation. Whereas AGE-modified proteins relatively well studied, aminophospholipid AGE-adducts have been less intensively investigated. At elevated concentrations, glucose can react with amino groups of phosphatidylethanolamines (PE) to form Schiff bases or Amadori products, which can be further converted, under oxidative conditions, to various AGEs. Many of these products such as carboxymethylamine (CMA) and carboxyethylamine (CEA) can be formed by oxidative degradation of Amadori-products. The aim of this work was to investigate the different glycation and glycoxidation PE-adducts and to elucidate the most prominent mechanisms of AGE-PE formation.Four different aminophospholipids,[dipalmitoyl-(DPPE), palmitoyl-oleoyl-(POPE), palmitoyl-linoleoyl-(PLPE) or palmitoyl-arachidonoyl-phosphatidylethanolamine(PAPE); all 1mmol/L] were glycated in vitro (5mmol/L glucose) and oxidized by the Fenton reaction (80µmol/L FeSO4, 50mmol/L H2O2) or using electrochemical oxidation (Roxy EC System, Antec, Leiden, Netherlands). High resolution mass spectrometry (MS) in combination with MSn fragmentation allowed the identification of major products, such as CMA, CEA and oxo-glucuronic acid. The mechanism of CMA/CME formation by oxidative degradation of the Amadori product was confirmed by co-oxidation (Fenton reaction) of purified glycated (gPOPE) with nonglycated DPPE (Fenton reaction) and by electrochemical oxidation of purified gPOPE, whereas the reaction with glyoxal/methylglyoxal formed by glucose oxidation was excluded. In both cases CMA/CEA-POPE adducts were detected. When glycated with 1,2-13C glucose, DPPE-CMA/CME adducts contained two 13C atoms further confirming the proposed mechanism. Finally, the ability of glycated PE when co-incubated with cells (HeLa) to induce Nrf2 activation was also addressed.

Physical controls on CH<sub>4</sub> emissions from a newly flooded subtropical freshwater hydroelectric reservoir: Nam Theun 2

Abstract. In the present study, we measured independently CH4 ebullition and diffusion in the footprint of an eddy covariance system (EC) measuring CH4 emissions in the Nam Theun 2 Reservoir, a recently impounded (2008) subtropical hydroelectric reservoir located in the Lao People's Democratic Republic (PDR), Southeast Asia. The EC fluxes were very consistent with the sum of the two terms measured independently (diffusive fluxes + ebullition = EC fluxes), indicating that the EC system picked up both diffusive fluxes and ebullition from the reservoir. We showed a diurnal bimodal pattern of CH4 emissions anti-correlated with atmospheric pressure. During daytime, a large atmospheric pressure drop triggers CH4 ebullition (up to 100 mmol m−2 d−1), whereas at night, a more moderate peak of CH4 emissions was recorded. As a consequence, fluxes during daytime were twice as high as during nighttime. Additionally, more than 4800 discrete measurements of CH4 ebullition were performed at a weekly/fortnightly frequency, covering water depths ranging from 0.4 to 16 m and various types of flooded ecosystems. Methane ebullition varies significantly seasonally and depends mostly on water level change during the warm dry season, whereas no relationship was observed during the cold dry season. On average, ebullition was 8.5 ± 10.5 mmol m−2 d−1 and ranged from 0 to 201.7 mmol m−2 d−1. An artificial neural network (ANN) model could explain up to 46% of seasonal variability of ebullition by considering total static pressure (the sum of hydrostatic and atmospheric pressure), variations in the total static pressure, and bottom temperature as controlling factors. This model allowed extrapolation of CH4 ebullition on the reservoir scale and performance of gap filling over four years. Our results clearly showed a very high seasonality: 50% of the yearly CH4 ebullition occurs within four months of the warm dry season. Overall, ebullition contributed 60–80% of total emissions from the surface of the reservoir (disregarding downstream emissions), suggesting that ebullition is a major pathway in young hydroelectric reservoirs in the tropics.

ORR Activity for Pt/Pd(111) Bimetallic Surface Prepared By Molecular Beam Epitaxy

Background From the view-points of reduction in usage of expensive Pt and enhancement in oxygen reduction reaction (ORR) activity [1], Pt-shell and Pd-core, core-shell type nano-particles attract much interest as cathode-electrode materials for polymer electrolyte fuel cells. Relation between topmost surface structures of the core-shell nano-particles and ORR activities is a key for developing highly-active, low-Pt-content catalysts. However, disscussion of ORR mechanism is complicated. In this study, we prepared well-defined Pt/Pd(111) bimetallic surfaces by molecular beam epitaxy (MBE) in ultra-high vacuum (UHV) and performed EC measurements in an inert gas atomosphere. Experimental The MBE apparatus and UHV-EC sample transfer system have been described earlier [2]. All sample fabrication processes were conducted in UHV. Pd(111) single crystal substrate was cleaned by Ar+ sputtering and annealing. Various-thick Pt was deposited onto the clean Pd(111) by an electron-beam evaporation method at 673K. The resulting surface structures were verified with low energy electron diffraction (LEED), scanning tunelling microscope in UHV (UHV-STM). Then, the MBE-prepared Ptxnm/Pd(111) surfaces were transferred without being exposed to air to the EC system set in an N2-purged glove box. Cyclic voltammogram (CV) of the samples were recorded in N2-purged 0.1M HClO4, and, then, linear sweep voltammetry (LSV) was conducted by a rotating electrode (RDE) method at 1600 rpm after saturating the solution with O2. EC degradation of the Ptxnm/Pd(111) was evaluated by applying potential cycles between 0.6V (3s) and 1.0V (3s) vs. RHE. The potential-cycled Ptxnm/Pd(111) were re-transferred to the UHV-STM system to evaluate the potential-cycle-induced topmost surface structural changes. Results and discussion From the results obtained by LEED and IRRAS for carbon monoxide adsorption, we deduce that 0.6nm-thick Pt almost covers the Pd(111) substrate surface. A UHV-STM image of the Pt0.6nm/Pd(111) (inset in Fig. 1 (a)) clearly shows atomically-flat, wide terraces. Fig. 1 (a) shows CV curves of the Pt0.6nm/Pd(111) (blue). CV curves for clean Pt(111) (black) and Pd(111) (grey) are also presented as references. EC charge of the H-related features (0.15V-0.3V ; Qab&de) for the Pt0.6nm/Pd(111) markedly shirinks in comparison to that of clean Pd(111), suggesting that the topmost surface of the Pt0.6nm/Pd(111) is epitaxial Pt(111). Fig. 1 (b) shows LSV curves for the respective surfaces. A half-wave potential of the as-prepared Pt0.6nm/Pd(111) (blue) shifts positively relative to clean Pt(111), indicating ORR activity enhancement. The LSV curve of the as-prepared Pt0.6nm/Pd(111) shifts to lower potentials after the 1000 potential cycles (red), revealing potential-cycle induced surface degradation. One might notice that the red LSV curve is almost identical to that for 0.15nm-thick-Pd deposited Pt(111) (Pd0.15nm/Pt(111);green). The results obtained in this study suggest that the topmost surface of MBE-prepared Pt0.6nm/Pd(111) is degraded through dissolution and precipitation of the substrate Pd atoms during the potential cycles. Acknowledgement This work was supported by New Energy and Industrial Technology Development Organization (NEDO).

Optimization of the ITER electron cyclotron equatorial launcher for improved heating and current drive functional capabilities

The design of the ITER Electron Cyclotron Heating and Current Drive (EC H&CD) system has evolved in the last years both in goals and functionalities by considering an expanded range of applications. A large effort has been devoted to a better integration of the equatorial and the upper launchers, both from the point of view of the performance and of the design impact on the engineering constraints. However, from the analysis of the ECCD performance in two references H-mode scenarios at burn (the inductive H-mode and the advanced non-inductive scenario), it was clear that the EC power deposition was not optimal for steady-state applications in the plasma region around mid radius. An optimization study of the equatorial launcher is presented here aiming at removing this limitation of the EC system capabilities. Changing the steering of the equatorial launcher from toroidal to poloidal ensures EC power deposition out to the normalized toroidal radius ρ ≈ 0.6, and nearly doubles the EC driven current around mid radius, without significant performance degradation in the core plasma region. In addition to the improved performance, the proposed design change is able to relax some engineering design constraints on both launchers.

State-of-the-art neoclassical tearing mode control in DIII-D using real-time steerable electron cyclotron current drive launchers

Real-time steerable electron cyclotron current drive (ECCD) has been demonstrated to reduce the power requirements and time needed to remove 3/2 and 2/1 neoclassical tearing modes (NTMs) in the DIII-D tokamak. In a world first demonstration of the techniques required in ITER, the island formation onset is detected automatically, gyrotrons are turned on and the real-time steerable ECCD launcher mirrors are moved promptly to drive current at the location of the islands. This shrinks and suppresses the modes well before saturation using real-time motional Stark effect constrained equilibria reconstruction with advanced feedback and search algorithms to target the deposition. In ITER, this method will reduce the ECCD energy requirement and so raise Q by keeping the EC system off when the NTM is not present. Further, in the experiments with accurate tracking of pre-emptive ECCD to resonant surfaces, both 3/2 and 2/1 modes are prevented from appearing with much lower ECCD peak power than required for removal of a saturated mode.

Thread-based microfluidic system for detection of rapid blood urea nitrogen in whole blood

This study develops a thread-based microfluidic device with variable volume injection capability and 3-dimensional (3D) detection electrodes for capillary electrophoresis electrochemical (CE–EC) detection of blood urea nitrogen (BUN) in whole blood. A poly methyl methacrylate (PMMA) substrate with concave 3D electrodes produced by the hot embossing method is used to enhance the sensing performance of the CE–EC system. Results show that the chip with 3D sensing electrodes exhibits a measured current response nine times higher and signal-to-noise ratio five times higher when compared to the peak responses obtained using a chip with conventional 2D sensing electrodes. In addition, the developed thread-based microfluidic system is capable of injecting variable sample volumes into the separation thread simply by wrapping the injection thread different numbers of times around the separation thread. The peak S/N ratio can be further enhanced with this simple approach. Results also indicate that the CE–EC system exhibits good linear dynamic range for detecting a urea sample in concentrations from 0.1 to 10.0 mM (R 2 = 0.9848), which is suitable for adoption in detecting the BUN concentration in human blood (1.78–7.12 mM). Separation and detection of the ammonia ions converted from BUN in whole blood is successfully demonstrated in the present study, with the developed thread-based microfluidic system providing a low-cost, high-performance method for detecting BUN in human blood.

Preliminary Study on Blend Based Mixed Ion- Electron Conductor- (PVA: PVK): CH3COONH4: EC System

An attempt has been made in the present work to develop blend based mixed ion-electron conductor viz. PVA: PVK: CH3COONH4: EC system. Formation of polymer blend and composite has been evidenced during XRD and IR studies. Ionic conductivity of this system is seen to improve by an order of magnitude at room temperature with optimum at 1.27×10-3 S/cm for 0.4 mole ammonium acetate concentration. Ionic charge transport seems to dominate as reflected from I-t measurements. Temperature dependent conductivity shows that ionic conduction is controlled by combination of Arrhenius and VTF behavior. AC conductivity behavior is seen to be dictated by Jonscher Power law.

Quantification of anandamide and 2‐arachidonoylglycerol plasma levels to examine potential influences of tetrahydrocannabinol application on the endocannabinoid system in humans

The effects of tetrahydrocannabinol (THC) and endogenous cannabinoids (endocannabinoids, ECs) are both mediated by activation of the cannabinoid receptors CB1 and CB2. Exogenous activation of these receptors by THC could therefore alter EC levels. We tested this hypothesis in healthy volunteers (n = 25) who received a large intravenous dose of THC (0.10 mg/kg). Effects on the EC system were quantified by serial measurements of plasma ECs after THC administration. Eleven blood samples were drawn during the first 5 h after THC administration and two more samples after 24 and 48 h. THC, its metabolites THC-OH (biologically active) and THC-COOH (non-active), and the ECs anandamide and 2-arachidonoylglycerol (2-AG) were quantified by liquid chromatography-mass spectrometry. EC-plasma levels showed a biphasic response after THC injection reaching maximal values at 30 min. Anandamide increased slightly from 0.58 ± 0.21 ng/ml at baseline to 0.64 ± 0.24 ng/ml (p < 0.05) and 2-AG from 7.60 ± 4.30 ng/ml to 9.50 ± 5.90 ng/ml (p < 0.05). After reaching maximal concentrations, EC plasma levels decreased markedly to a nadir of 300 min after THC administration (to 0.32 ± 0.15 ng/ml for anandamide and to 5.50 ± 3.01 ng/ml for 2-AG, p < 0.05). EC plasma concentrations returned to near baseline levels until 48 h after the experiment. THC (0.76 ± 0.16 ng/ml) and THC-OH (0.36 ± 0.17 ng/ml) were still measurable at 24 h and remained detectible until 48 h after THC administration. Although the underlying mechanism is not clear, high doses of intravenous THC appear to influence endogenous cannabinoid concentrations and presumably EC-signalling.