WorldWideScience

Sample records for voltage dual comparators

  1. 46 CFR 129.326 - Dual-voltage generators.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Dual-voltage generators. 129.326 Section 129.326... INSTALLATIONS Power Sources and Distribution Systems § 129.326 Dual-voltage generators. If a dual-voltage generator is installed on an OSV— (a) The neutral of the dual-voltage system must be solidly grounded at...

  2. 46 CFR 120.324 - Dual voltage generators.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Dual voltage generators. 120.324 Section 120.324... INSTALLATION Power Sources and Distribution Systems § 120.324 Dual voltage generators. (a) A dual voltage generator installed on a vessel shall be of the grounded type, where: (1) The neutral of a dual...

  3. 46 CFR 183.324 - Dual voltage generators.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Dual voltage generators. 183.324 Section 183.324... TONS) ELECTRICAL INSTALLATION Power Sources and Distribution Systems § 183.324 Dual voltage generators. (a) A dual voltage generator installed on a vessel shall be of the grounded type, where: (1)...

  4. Dual voltage power supply with 48 volt

    Energy Technology Data Exchange (ETDEWEB)

    Froeschl, Joachim; Proebstle, Hartmut; Sirch, Ottmar [BMW Group, Muenchen (Germany)

    2012-11-01

    Automotive electrics/electronics have just reached a period of tremendous change. High voltage systems for Hybrid, Plug-In Hybrid or Battery Electric Vehicles with high power electric motors, high energy accumulators and electric climate compressors will be introduced in order to achieve the challenging targets for CO{sub 2} emissions and energy efficiency and to anticipate the mobility of the future. Additionally, innovations and the continuous increase of functionality for comfort, safety, driver assistance and infotainment systems require more and more electrical power of the vehicle power supply at all. On the one hand side electrified vehicles will certainly achieve a significant market share, on the other hand side they will increase the pressure to conventional vehicles with combustion engines for fuel consumption and CO{sub 2} emissions. These vehicles will be enabled to keep their competitiveness by new functions and the optimization of their electric systems. A dual voltage power supply with 48 Volt and 12 Volt will be one of the key technologies to realize these requirements. The power capability of the existing 12 Volt power supply has reached its limits. Further potentials can only be admitted by the introduction of 48 Volt. For this reason the car manufacturers Audi, BMW, Daimler, Porsche and Volkswagen started very early on this item and developed a common specification of the new voltage range. Now, it is necessary to identify the probable systems at this voltage range and to start the developments. (orig.)

  5. Large format voltage tunable dual-band QWIP FPAs

    Science.gov (United States)

    Arslan, Y.; Eker, S. U.; Kaldirim, M.; Besikci, C.

    2009-11-01

    Third generation thermal imagers with dual/multi-band operation capability are the prominent focus of the current research in the field of infrared detection. Dual band quantum-well infrared photodetector (QWIP) focal plane arrays (FPAs) based on various detection and fabrication approaches have been reported. One of these approaches is the three-contact design allowing simultaneous integration of the signals in both bands. However, this approach requires three In bumps on each pixel leading to a complicated fabrication process and lower fill factor. If the spectral response of a two-stack QWIP structure can effectively be shifted between two spectral bands with the applied bias, dual band sensors can be implemented with the conventional FPA fabrication process requiring only one In bump on each pixel making it possible to fabricate large format dual band FPAs at the cost and yield of single band detectors. While some disadvantages of this technique have been discussed in the literature, the detailed assessment of this approach has not been performed at the FPA level yet. We report the characteristics of a large format (640 × 512) voltage tunable dual-band QWIP FPA constructed through series connection of MWIR AlGaAs-InGaAs and LWIR AlGaAs-GaAs multi-quantum well stacks, and provide a detailed assessment of the potential of this approach at both pixel and FPA levels. The dual band FPA having MWIR and LWIR cut-off wavelengths of 5.1 and 8.9 μm provided noise equivalent temperature differences as low as 14 and 31 mK ( f/1.5) with switching voltages within the limits applicable by commercial read-out integrated circuits. The results demonstrate the promise of the approach for achieving large format low cost dual band FPAs.

  6. To Implement Energy Efficient of Integer Unit by Higher Voltage Flip Flop Based on Minimum operating Dual Supply Voltage Techinque

    Directory of Open Access Journals (Sweden)

    M. Subhashini,

    2014-06-01

    Full Text Available To achieve the most energy-efficient operation, this brief presents a circuit design technique for separating the power supply voltage (VDD of flip-flops (FFs from that of combinational circuits, called the higher voltage FF (HVFF. Although VDD scaling can reduce the energy, the minimum operating voltage (VDDmin of FFs prevents the operation at the optimum supply voltage that minimizes the energy, because the VDDmin of FFs is higher than the optimum supply voltage. In HVFF, the VDD of combinational logic gates is reduced below the VDDmin of FFs while keeping the VDD of FFs at their VDDmin. This makes it possible to minimize the energy without power and delay penalties at the nominal supply voltage (1.2 V as well as without FF topological difications. A four bit alu is designed in these paper by using dual supply voltage usig DSCH.

  7. Comprehensive behavioral model of dual-gate high voltage JFET and pinch resistor

    Science.gov (United States)

    Banáš, Stanislav; Paňko, Václav; Dobeš, Josef; Hanyš, Petr; Divín, Jan

    2016-09-01

    Many analog technologies operate in large voltage range and therefore include at least one or more high voltage devices built from low doped layers. Such devices exhibit effects not covered by standard compact models, namely pinching (depletion) effects, in high voltage FETs often called quasisaturation. For example, the conventional compact JFET model is insufficient and oversimplified. Its scalability is controlled by the area factor, which only multiplies currents and capacitances but does not take into account existing 3-D effects. Also the optional second independent gate is missing. Therefore, the customized four terminal (4T) model written in Verilog-A (FitzPatrick and Miller, 2007; Sagdeo, 2007) was developed. It converges very well, its simulation speed is comparable with conventional compact models, and contains all required phenomena, including parasitic effects as, for example, impact ionization. This model has universal usage for many types of devices in various high voltage technologies such as stand-alone voltage dependent resistor, pinch resistor, drift area of power FET, part of special high side or start-up devices, and dual-gate JFET.

  8. Exploration of dual supply voltage logic synthesis in state-of-the-art ASIC design flows

    Directory of Open Access Journals (Sweden)

    T. Mahnke

    2003-01-01

    Full Text Available Dual supply voltage scaling (DSVS for logiclevel power optimization at the has increasingly attracted attention over the last few years. However, mainly due to the fact that the most widely used design tools do not support this new technique, it has still not become an integral part of real-world design flows. In this paper, a novel logic synthesis methodology that enables DSVS while relying entirely on standard tools is presented. The key to this methodology is a suitably modeled dual supply voltage (DSV standard cell library. A basic evaluation of the methodology has been carried out on a number of MCNC benchmark circuits. In all these experiments, the results of state-of-the-art powerdriven single supply voltage (SSV logic synthesis have been used as references in order to determine the true additional benefit of DSVS. Compared with the results of SSV power optimization, additional power reductions of 10% on average have been achieved. The results prove the feasibility of the new approach and reveal its greater efficiency in comparison with a well-known dedicated DSVS algorithm. Finally, the methodology has been applied to an embedded microcontroller core in order to further explore the potentials and limitations of DSVS in an existing industrial design environment.

  9. Dual design resistor for high voltage conditioning and transmission lines

    Science.gov (United States)

    Siggins, Timothy Lynn [Newport News, VA; Murray, Charles W [Hayes, VA; Walker, Richard L [Norfolk, VA

    2007-01-23

    A dual resistor for eliminating the requirement for two different value resistors. The dual resistor includes a conditioning resistor at a high resistance value and a run resistor at a low resistance value. The run resistor can travel inside the conditioning resistor. The run resistor is capable of being advanced by a drive assembly until an electrical path is completed through the run resistor thereby shorting out the conditioning resistor and allowing the lower resistance run resistor to take over as the current carrier.

  10. High voltage and high specific capacity dual intercalating electrode Li-ion batteries

    Science.gov (United States)

    West, William C. (Inventor); Blanco, Mario (Inventor)

    2010-01-01

    The present invention provides high capacity and high voltage Li-ion batteries that have a carbonaceous cathode and a nonaqueous electrolyte solution comprising LiF salt and an anion receptor that binds the fluoride ion. The batteries can comprise dual intercalating electrode Li ion batteries. Methods of the present invention use a cathode and electrode pair, wherein each of the electrodes reversibly intercalate ions provided by a LiF salt to make a high voltage and high specific capacity dual intercalating electrode Li-ion battery. The present methods and systems provide high-capacity batteries particularly useful in powering devices where minimizing battery mass is important.

  11. A Voltage Doubler Circuit to Extend the Soft-switching Range of Dual Active Bridge Converters

    DEFF Research Database (Denmark)

    Qin, Zian; Shen, Yanfeng; Wang, Huai;

    2017-01-01

    A voltage doubler circuit is realized to extend the soft-switching range of Dual Active Bridge (DAB) converters. No extra hardware is added to the DAB to form this circuit, since it is composed of the dc blocking capacitor and the low side full bridge converter, which already exist in DAB. With t...

  12. Synchronized PWM Scheme for Dual Inverter-Fed Drives with Zero Common-Mode Voltages

    DEFF Research Database (Denmark)

    Oleschuk, Valentin; Blaabjerg, Frede; Chen, Zhe;

    2005-01-01

    the whole control range including the zone of overmodulation. Spectra of the phase voltage do not contain even harmonics and sub-harmonics (combined harmonics), which is especially important for the drive systems with increased power rating. Simulations gave the behaviour of dual inverter-fed system...

  13. A dual VCDL DLL based gate driver for zero-voltage-switching DC-DC converter

    Science.gov (United States)

    Xin, Tian; Xiangxin, Liu; Wenhong, Li

    2010-07-01

    This paper presents a dual voltage-controlled-delay-line (VCDL) delay-lock-loop (DLL) based gate driver for a zero-voltage-switching (ZVS) DC-DC converter. Using the delay difference of two VCDLs for the dead time control, the dual VCDL DLL is able to implement ZVS control with high accuracy while keeping good linearity performance of the DLL and low power consumption. The design is implemented in the CSM 2P4M 0.35 μm CMOS process. The measurement results indicate that an efficiency improvement of 2%-4% is achieved over the load current range from 100 to 600 mA at 4 MHz switching frequency with 3.3 V input and 1.3 V output voltage.

  14. A dual VCDL DLL based gate driver for zero-voltage-switching DC-DC converter

    Energy Technology Data Exchange (ETDEWEB)

    Tian Xin; Liu Xiangxin; Li Wenhong, E-mail: wenhongli@fudan.edu.c [State Key Laboratory of ASIC and System, Fudan University, Shanghai 201203 (China)

    2010-07-15

    This paper presents a dual voltage-controlled-delay-line (VCDL) delay-lock-loop (DLL) based gate driver for a zero-voltage-switching (ZVS) DC-DC converter. Using the delay difference of two VCDLs for the dead time control, the dual VCDL DLL is able to implement ZVS control with high accuracy while keeping good linearity performance of the DLL and low power consumption. The design is implemented in the CSM 2P4M 0.35 {mu}m CMOS process. The measurement results indicate that an efficiency improvement of 2%-4% is achieved over the load current range from 100 to 600 mA at 4 MHz switching frequency with 3.3 V input and 1.3 V output voltage.

  15. A comparative study for Triple-Rule-out with different tube voltage technique of Dual-Source CT in acute chest pain%双源 CT不同管电压技术诊断急性胸痛三联症效果比较

    Institute of Scientific and Technical Information of China (English)

    王皆欢; 陈东风; 王少春; 孙占国; 王林省; 张谷青

    2014-01-01

    目的:对比双源CT胸痛三联检查在两种不同电压下显示急性胸痛患者肺动脉、主动脉及冠状动脉的图像质量以及患者所受的辐射剂量,以评估低电压扫描在急性胸痛患者推广应用的可行性。方法利用双源C T胸痛三联扫描模式,结合回顾性心电门控技术对361例胸痛三联检查患者进行统计分析,比较主动脉、肺动脉及冠状动脉的图像质量及辐射的有效剂量。结果120kV组与100kV组在图像质量的主观评分对比中差异无统计学意义(P>0.05),在患者辐射剂量的对比中,120kV组的辐射剂量大于100kV组,差异有统计学意义(P<0.05)。结论双源CT胸痛三联检查两种不同管电压扫描对急性胸痛患者的肺动脉、主动脉及冠状动脉的成像质量无影响,并且应用100kV 管电压扫描可以降低患者所受的辐射剂量,可以作为急性胸痛患者的首选。%Objective To compare the value of triple-rule-out (TRO) dual-source computed tomography angiog-raphy in acute chest pain patients with diseases of pulmonary artery ,aortic and coronary artery and radiation dose in two different voltage as well as the feasibility of generalizing and applying in patients with acute chest pain . Methods 361 patients with chest pain were analyzed statistically underwent triple-rule-out (TRO) dual-source CT combined with retrospective ECG-gated technique ,and then compare with image quality of aorta ,pulmonary artery and coronary artery and effective radiation dose .Results Subjective score of image quality of the voltage 120kV and 100kV group had no statistical significance(P>0.05) .The difference was statistically significant(P<0.05)in comparison of radiation dose .The effective radiation dose of the voltage 100kV group was lower than that of the voltage 120kV group .Conclusion The quality of pictures of pulmonary artery ,coronary artery and aorta are not affected in different tube tension

  16. A dual-mode phase-shift modulation control scheme for voltage multiplier based X-ray power supply

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, S [School of Electrical and Electronics Engineering, University Sains Malaysia, 14300 Nibong Tebal, Pulau Pinang (Malaysia); Besar, R; Venkataseshaiah, C, E-mail: shahidsidu@hotmail.co [Faculty of Engineering and Technology, Multimedia University, 75450 Melaka (Malaysia)

    2010-05-15

    This paper proposes a dual-mode phase-shift modulation control scheme for series resonant inverter fed voltage multiplier (VM) based X-ray power supply. In this control scheme the outputs voltage of two parallel connected series resonant inverters are mixed before supplying to VM circuit. The output voltage of the power supply is controlled by varying the phase-shift between the output voltages of two inverters. In order to achieve quick rise of output voltage, the power supply is started with zero phase-shift and as the output voltage reaches 90% of the target voltage, the phase-shift is increased to a value which corresponds to target output voltage to prevent overshoot. The proposed control scheme has been shown to have good performance. Experimental results based on the scaled-down laboratory prototype are presented to validate the effectiveness of proposed dual-mode phase shift modulation control scheme.

  17. A dual voltage control strategy for single-phase PWM converters with power decoupling function

    DEFF Research Database (Denmark)

    Tang, Yi; Qin, Zian; Blaabjerg, Frede

    2014-01-01

    on a symmetrical half bridge circuit is proposed to decouple the ripple power so that balanced instantaneous power flow is assured between source and load, and the required dc-link capacitance can be dramatically reduced. For proper closed-loop regulation, the small signal modeling of the proposed system...... is presented, and a dual voltage control strategy is then proposed, which comprises one voltage loop implemented in the synchronous reference frame for active power balancing, and another one implemented in the harmonic reference frame for ripple power compensation. Special attention is given to the bandwidth...

  18. Dual Regulation of Voltage-Sensitive Ion Channels by PIP(2).

    Science.gov (United States)

    Rodríguez-Menchaca, Aldo A; Adney, Scott K; Zhou, Lei; Logothetis, Diomedes E

    2012-01-01

    Over the past 16 years, there has been an impressive number of ion channels shown to be sensitive to the major phosphoinositide in the plasma membrane, phosphatidylinositol 4,5-bisphosphate (PIP(2)). Among them are voltage-gated channels, which are crucial for both neuronal and cardiac excitability. Voltage-gated calcium (Cav) channels were shown to be regulated bidirectionally by PIP(2). On one hand, PIP(2) stabilized their activity by reducing current rundown but on the other hand it produced a voltage-dependent inhibition by shifting the activation curve to more positive voltages. For voltage-gated potassium (Kv) channels PIP(2) was first shown to prevent N-type inactivation regardless of whether the fast inactivation gate was part of the pore-forming α subunit or of an accessory β subunit. Careful examination of the effects of PIP(2) on the activation mechanism of Kv1.2 has shown a similar bidirectional regulation as in the Cav channels. The two effects could be distinguished kinetically, in terms of their sensitivities to PIP(2) and by distinct molecular determinants. The rightward shift of the Kv1.2 voltage dependence implicated basic residues in the S4-S5 linker and was consistent with stabilization of the inactive state of the voltage sensor. A third type of a voltage-gated ion channel modulated by PIP(2) is the hyperpolarization-activated cyclic nucleotide-gated (HCN) channel. PIP(2) has been shown to enhance the opening of HCN channels by shifting their voltage-dependent activation toward depolarized potentials. The sea urchin HCN channel, SpIH, showed again a PIP(2)-mediated bidirectional effect but in reverse order than the depolarization-activated Cav and Kv channels: a voltage-dependent potentiation, like the mammalian HCN channels, but also an inhibition of the cGMP-induced current activation. Just like the Kv1.2 channels, distinct molecular determinants underlied the PIP(2) dual effects on SpIH, with the proximal C-terminus implicated in the

  19. Dual Regulation of Voltage-Sensitive Ion Channels by PIP2

    Directory of Open Access Journals (Sweden)

    Aldo A Rodríguez Menchaca

    2012-09-01

    Full Text Available Over the past 16 years, there has been an impressive number of ion channels shown to be sensitive to the major phosphoinositide in the plasma membrane, phosphatidilinositol 4,5-bisphosphate (PIP2. Among them are voltage-gated channels, which are crucial for both neuronal and cardiac excitability. Voltage-gated calcium (Cav channels were shown to be regulated bidirectionally by PIP2. On one hand, PIP2 stabilized their activity by reducing current rundown but on the other hand it produced a voltage-dependent inhibition by shifting the activation curve to more positive voltages. For voltage-gated potassium (Kv channels PIP2 was first shown to prevent N-type inactivation. Careful examination of the effects of PIP2 on the activation mechanism of Kv1.2 has shown a similar bidirectional regulation as in the Cav channels. The two effects could be distinguished kinetically, in terms of their sensitivities to PIP2 and by distinct molecular determinants. The rightward shift of the Kv1.2 voltage dependence implicated basic residues in the S4-S5 linker and was consistent with stabilization of the inactive state of the voltage sensor. A third type of a voltage-gated ion channel modulated by PIP2 is the hyperpolarization-activated cyclic nucleotide-gated (HCN channel. PIP2 has been shown to enhance the opening of HCN channels by shifting their voltage-dependent activation toward depolarized potentials. The sea urchin HCN channel, SpIH, showed again a PIP2-mediated bidirectional effect but in reverse order than the depolarization-activated Cav and Kv channels: a voltage-dependent potentiation, like the mammalian HCN channels, but also an inhibition of the cGMP-induced current activation. Just like the Kv1.2 channels, distinct molecular determinants underlied the PIP2 dual effects on SpIH channels. The dual regulation of these very different ion channels, all of which are voltage dependent, points to conserved mechanisms of regulation of these channels by PIP2.

  20. A dual voltage control strategy for single-phase PWM converters with power decoupling function

    DEFF Research Database (Denmark)

    Tang, Yi; Qin, Zian; Blaabjerg, Frede

    2014-01-01

    The inherent double line ripple power in singlephase systems is adverse to the converter performance, e.g. limited lifetime due to the requirement of large electrolytic capacitors and low voltage control bandwidth due to harmonic disturbance. In this paper, an active converter topology based...... on a symmetrical half bridge circuit is proposed to decouple the ripple power so that balanced instantaneous power flow is assured between source and load, and the required dc-link capacitance can be dramatically reduced. For proper closed-loop regulation, the small signal modeling of the proposed system...... is presented, and a dual voltage control strategy is then proposed, which comprises one voltage loop implemented in the synchronous reference frame for active power balancing, and another one implemented in the harmonic reference frame for ripple power compensation. Special attention is given to the bandwidth...

  1. A dual voltage control strategy for single-phase PWM converters with power decoupling function

    DEFF Research Database (Denmark)

    Tang, Yi; Qin, Zian; Blaabjerg, Frede

    2015-01-01

    converter topology based on a symmetrical half bridge circuit is proposed to decouple the ripple power so that balanced instantaneous power flow is assured between source and load, and the required dc-link capacitance can be dramatically reduced. For proper closed-loop regulation, the small signal modeling......The inherent double line ripple power in single-phase systems is adverse to the performance of power electronics converters, e.g. limited lifetime due to the requirement of large electrolytic capacitors and low voltage control bandwidth due to harmonic disturbance. In this paper, an active...... of the proposed system is presented, and a dual voltage control strategy is then proposed, which comprises one voltage loop implemented in the synchronous reference frame for active power balancing, and another one implemented in the stationary reference frame for ripple power compensation. Special attention...

  2. Design of a constant-voltage and constant-current controller with dual-loop and adaptive switching frequency control

    Science.gov (United States)

    Yingping, Chen; Zhiqian, Li

    2015-05-01

    A 5.0-V 2.0-A flyback power supply controller providing constant-voltage (CV) and constant-current (CC) output regulation without the use of an optical coupler is presented. Dual-close-loop control is proposed here due to its better regulation performance of tolerance over process and temperature compared with open loop control used in common. At the same time, the two modes, CC and CV, could switch to each other automatically and smoothly according to the output voltage level not sacrificing the regulation accuracy at the switching phase, which overcomes the drawback of the digital control scheme depending on a hysteresis comparator to change the mode. On-chip compensation using active capacitor multiplier technique is applied to stabilize the voltage loop, eliminate an additional package pin, and save on the die area. The system consumes as little as 100 mW at no-load condition without degrading the transient response performance by utilizing the adaptive switching frequency control mode. The proposed controller has been implemented in a commercial 0.35-μm 40-V BCD process, and the active chip area is 1.5 × 1.0 mm2. The total error of the output voltage due to line and load variations is less than ±1.7%.

  3. Dual trench AlGaN/GaN HEMT on SiC substrate: A novel device to improve the breakdown voltage and high power performance

    Science.gov (United States)

    Ghaffari, Majid; Orouji, Ali A.

    2016-06-01

    In this paper, an excellent performance AlGaN/AlN/GaN/SiC High Electron Mobility Transistor (HEMT) with a dual trench technique (DT-HEMT) is proposed. In the proposed technique, the dual trench between the buffer layer and the nucleation layer is created. Both the trenches are made of Gallium Nitride. A trench is created under the source region to increase the breakdown voltage. In addition, the drain current will improve due to a created trench in below the gate region. The DC and RF characteristics of the DT-HEMT are investigated. Also, the characteristics of the proposed structure compared with the characteristics of a conventional structure (C-HEMT). Our results indicate that the dual trench technique has excellent impacts on the device characteristics, especially on the drain current, breakdown voltage, and maximum output power density. The breakdown voltage, drain current, and maximum power density of DT-HEMT structure improve 56 %, 52 %, and 310 % in comparison with the C-HEMT, respectively. Also, using the dual trench technique, the maximum oscillation frequency, maximum available gain, short channel effect, maximum DC transconductance, and output resistance of the DT-HEMT structure will increase. Therefore, the proposed HEMT structure shows outstanding electrical properties compared to similar devices are based on conventional structures.

  4. Dual-harmonic auto voltage control for the rapid cycling synchrotron of the Japan Proton Accelerator Research Complex

    Directory of Open Access Journals (Sweden)

    Fumihiko Tamura

    2008-07-01

    Full Text Available The dual-harmonic operation, in which the accelerating cavities are driven by the superposition of the fundamental and the second harmonic rf voltage, is useful for acceleration of the ultrahigh intensity proton beam in the rapid cycling synchrotron (RCS of Japan Proton Accelerator Research Complex (J-PARC. However, the precise and fast voltage control of the harmonics is necessary to realize the dual-harmonic acceleration. We developed the dual-harmonic auto voltage control system for the J-PARC RCS. We describe details of the design and the implementation. Various tests of the system are performed with the RCS rf system. Also, a preliminary beam test has been done. We report the test results.

  5. Electrospinning of fibrous polymer scaffolds using positive voltage or negative voltage: a comparative study.

    Science.gov (United States)

    Tong, Ho-Wang; Wang, Min

    2010-10-01

    Electrospinning of fibrous tissue engineering scaffolds has been traditionally conducted using positive voltages. In the current study, positive voltage (PV) electrospinning and negative voltage (NV) electrospinning were investigated for forming fibrous membranes of poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV). In both PV-electrospinning and NV-electrospinning, the fiber diameter generally increased with increasing needle inner diameter and PHBV concentration but decreased with increasing working distance. The use of a conductivity-enhancing surfactant, benzyl triethylammonium chloride (BTEAC), significantly reduced PHBV fiber diameters from the micron scale to the sub-micron scale. Interestingly, with increasing applied voltage, the fiber diameter increased for PV-electrospinning but decreased for NV-electrospinning. The PV-electrospun fibrous membranes from solutions without BTEAC (PVEfm) and with BTEAC (PVEfm-B) and NV-electrospun membranes from solutions without BTEAC (NVEfm) and with BTEAC (NVEfm-B) were characterized in terms of their structure, wettability, thermal properties and tensile properties. Both PVEfm and NVEfm exhibited similar water contact angles (∼104°) but the contact angle of PVEfm-B or NVEfm-B was not measurable. The elongation at break of PVEfm-B or NVEfm-B was significantly higher than that of PVEfm or NVEfm. Using NV-electrospinning or a combination of NV- and PV-electrospinning may be very useful for developing suitable scaffolds for tissue engineering applications.

  6. A comparative study for detection and measurement of voltage disturbance in online condition

    Directory of Open Access Journals (Sweden)

    Vijay Gajanan Neve

    2015-05-01

    Full Text Available Voltage disturbance is the most important power quality problem faced by many industrial customers. It includes voltage sag, swell, spikes and harmonics. Real time detection of these voltage disturbances posed various problems. This paper compares the various methods of detection of voltage sag and swells in real time on the basis of detection time, magnitude, effect of windowing and effect of sampling frequencies. The RMS, Peak, Fourier transform and Missing Voltage algorithm are introduced and discussed in them for real time implementation. Comparative analysis reveals that quantification of voltage sag and swell is possible using these measurements. The main focus is given on to these points and all the voltage sag and swell detection technique tested online with the help of advantech card data acquisition. The voltage sag and swell events are generated by using practical experimentation in laboratory.

  7. Automated attenuation-based tube voltage selection for body CTA: Performance evaluation of 192-slice dual-source CT

    Energy Technology Data Exchange (ETDEWEB)

    Winklehner, Anna; Gordic, Sonja; Lauk, Eliane; Frauenfelder, Thomas; Alkadhi, Hatem; Husarik, Daniela B. [University Hospital Zurich, Institute for Diagnostic and Interventional Radiology, Zurich (Switzerland); Leschka, Sebastian [University Hospital Zurich, Institute for Diagnostic and Interventional Radiology, Zurich (Switzerland); Division of Radiology and Nuclear Medicine, St. Gallen (Switzerland)

    2015-08-15

    To assess radiation dose and image quality in body CT-angiography (CTA) with automated attenuation-based tube voltage selection (ATVS) on a 192-slice dual-source CT (DSCT). Forty patients (69.5 ± 9.6 years) who had undergone body CTA with ATVS (ref.kVp 100, ref.mAs 90) using a 2x192-slice CT in single-source mode were retrospectively included. All patients had undergone prior CTA with a 2x128-slice CT and ATVS with identical imaging and contrast media protocols, serving for comparison. Images were reconstructed with iterative reconstruction at similar strength levels. Radiation dose was determined. Image quality was assessed semi-quantitatively (1:excellent, 5:non-diagnostic), aortic attenuation, noise and CNR were determined. As compared to 128-slice DSCT, 192-slice DSCT selected tube voltages were lower in 30 patients (75 %), higher in 3 (7.5 %), and similar in 7 patients (17.5 %). CTDI{sub vol} was lower with 192-slice DSCT (4.7 ± 1.9 mGy vs. 5.8 ± 2.1 mGy; p < 0.001). Subjective image quality, mean aortic attenuation (342 ± 67HU vs. 268 ± 67HU) and CNR (9.8 ± 2.5 vs. 8.2 ± 2.9) were higher with 192-slice DSCT (all p < 0.01), all datasets being diagnostic. Our study suggests that ATVS of 192-slice DSCT for body CTA is associated with an improved image quality and further radiation dose reduction of 19 % compared to 128-slice DSCT. (orig.)

  8. Electronically Tunable Dual-Input Integrator Employing a Single CDBA and a Multiplier: Voltage Controlled Quadrature Oscillator Design

    Directory of Open Access Journals (Sweden)

    R. Nandi

    2009-01-01

    Full Text Available A new dual-input differential input active integrator using a current differencing buffered amplifier (CDBA is proposed. A multiplier element is appropriately used in the circuit whose control voltage (Vc tunes the integrator time constant (τ electronically. The design of a voltage controlled quadrature oscillator (VCQO based on the proposed integrator had been satisfactorily implemented. A new type of measurement for the tuning error of the oscillator based on the Nyquist plot is presented that shows an error of only 2% at fo≈ 1 MHz with Total Harmonic Distortion (THD less than 3%.

  9. Comparative study on power generation of dual-cathode microbial fuel cell according to polarization methods.

    Science.gov (United States)

    Lee, Kang-yu; Ryu, Wyan-seuk; Cho, Sung-il; Lim, Kyeong-ho

    2015-11-01

    Microbial fuel cells (MFCs) exist in various forms depending on the type of pollutant to be removed and the expected performance. Dual-cathode MFCs, with their simple structure, are capable of removing both organic matter and nitrogen. Moreover, various methods are available for the collection of polarization data, which can be used to calculate the maximum power density, an important factor of MFCs. Many researchers prefer the method of varying the external resistance in a single-cycle due to the short measurement time and high accuracy. This study compared power densities of dual-cathode MFCs in a single-cycle with values calculated over multi-cycles to determine the optimal polarization method. External resistance was varied from high to low and vice versa in the single-cycle, to calculate power density. External resistance was organized in descending order with initial start-up at open circuit voltage (OCV), and then it was organized in descending order again after the initial start-up at 1000 Ω. As a result, power density was underestimated at the anoxic cathode when the external resistance was varied from low to high, and overestimated at the aerobic cathode and anoxic cathode when external resistance at OCV was reduced following initial start-up. In calculating the power densities of dual-cathode MFCs, this paper recommends the method of gradually reducing the external resistance after initial start-up with high external resistance.

  10. Development of Optical Voltage Transducer Based on Dual-Mode Highly Elliptical-Core Polarization Maintenance Fiber

    Institute of Scientific and Technical Information of China (English)

    Wei-Hong Bi; Feng Liu; Xuan Guo

    2008-01-01

    This paper describes an optical voltage transducer (OVT) for the 35 kV electric power system based on modular interference in dual-mode highly elliptical-core polarization maintenance fiber (E-Core PMIF). The temperature and environmental perturb-bation can be compensated automatically. In the scheme, a quartz crystal cylinder wrapped with highly elliptical-core fiber plays the role of voltage sensor head. The two interference output lobes' intensity from the E-core PMF is modulated with the converse piezoelectric effect of quartz crystal. A PZT wrapped with E-core PMF at ground potential serves as the static modular phase difference control and temperature compensation unit. The experiment results indicate that the OVT designed in this paper has satisfying performance and could successfully rejects the temperature perturbation.

  11. Predictive value of low tube voltage and dual-energy CT for successful shock wave lithotripsy: an in vitro study.

    Science.gov (United States)

    Largo, Remo; Stolzmann, Paul; Fankhauser, Christian D; Poyet, Cédric; Wolfsgruber, Pirmin; Sulser, Tullio; Alkadhi, Hatem; Winklhofer, Sebastian

    2016-06-01

    This study investigates the capabilities of low tube voltage computed tomography (CT) and dual-energy CT (DECT) for predicting successful shock wave lithotripsy (SWL) of urinary stones in vitro. A total of 33 urinary calculi (six different chemical compositions; mean size 6 ± 3 mm) were scanned using a dual-source CT machine with single- (120 kVp) and dual-energy settings (80/150, 100/150 Sn kVp) resulting in six different datasets. The attenuation (Hounsfield Units) of calculi was measured on single-energy CT images and the dual-energy indices (DEIs) were calculated from DECT acquisitions. Calculi underwent SWL and the number of shock waves for successful disintegration was recorded. The prediction of required shock waves regarding stone attenuation/DEI was calculated using regression analysis (adjusted for stone size and composition) and the correlation between CT attenuation/DEI and the number of shock waves was assessed for all datasets. The median number of shock waves for successful stone disintegration was 72 (interquartile range 30-361). CT attenuation/DEI of stones was a significant, independent predictor (P waves with the best prediction at 80 kVp (β estimate 0.576) (P waves ranged between ρ = 0.31 and 0.68 showing the best correlation at 80 kVp (P < 0.001). The attenuation of urinary stones at low tube voltage CT is the best predictor for successful stone disintegration, being independent of stone composition and size. DECT shows no added value for predicting the success of SWL.

  12. A Comparative Study of Ultra-Low Voltage Digital Circuit Design

    Directory of Open Access Journals (Sweden)

    Aaron Arthurs

    2012-07-01

    Full Text Available Ultra-low voltage digital circuit design is an active research area, especially for portable applications such as wearable electronics, intelligent remote sensors, implantable medical devices, and energy-harvesting systems. Due to their application scenarios and circuit components, two major goals for these systems are minimizing energy consumption and improving compatibility with low-voltage power supplies and analog components. The most effective solution to achieve these goals is to reduce the supply voltage, which,however, raises the issue of operability. At ultra-low supply voltages, the integrity of digital signals degrades dramatically due to the indifference between active and leakage currents. In addition, the system timing becomes more unpredictable as the impact of process and supply voltage variations being more significant at lower voltages. This paper presents a comparative study among three techniques for designing digital circuits operating at ultra-low voltages, i.e., Schmitt-triggered gate structure, delayinsensitive asynchronous logic, and Fully-Depleted Silicon-on-Insulator technology. Results show that despite the tradeoffs, all eight combinations of these techniques are viable for designing ultra-low voltage circuits. For a given application, the optimum circuit design can be selected from these combinations based on the lowest voltage, the dynamic range, the power budget, the performance requirement, and the available semiconductor process node.

  13. A Comparative Study of Ultra-Low Voltage Digital Circuit Design

    Directory of Open Access Journals (Sweden)

    Aaron Arthurs,

    2012-06-01

    Full Text Available Ultra-low voltage digital circuit design is an active research area, especially for portable applications such as wearable electronics, intelligent remote sensors, implantable medical devices, and energy-harvesting systems. Due to their application scenarios and circuit components, two major goals for these systems are minimizing energy consumption and improving compatibility with low-voltage power supplies and analog components. The most effective solution to achieve these goals is to reduce the supply voltage, which,however, raises the issue of operability. At ultra-low supply voltages, the integrity of digital signals degrades dramatically due to the indifference between active and leakage currents. In addition, the system timing becomes more unpredictable as the impact of process and supply voltage variations being more significant at lower voltages. This paper presents a comparative study among three techniques for designing digital circuits operating at ultra-low voltages, i.e., Schmitt-triggered gate structure, delay insensitive asynchronous logic, and Fully-Depleted Silicon-on-Insulator technology. Results show that despite the trade offs, all eight combinations of these techniques are viable for designing ultra-low voltage circuits. For a given application, the optimum circuit design can be selected from these combinations based on the lowest voltage, the dynamic range, the power budget, the performance requirement, and the available semiconductor process node.

  14. Toward the design of high voltage magnesium–lithium hybrid batteries using dual-salt electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Yingwen; Choi, Daiwon; Han, Kee Sung; Mueller, Karl T.; Zhang, Ji-Guang; Sprenkle, Vincent L.; Liu, Jun; Li, Guosheng

    2016-02-26

    We report a design of high voltage magnesium-lithium (Mg-Li) hybrid batteries through rational controls of the electrolyte chemistry, electrode materials and cell architectures. Prototype devices with LiFePO4 and LiMn2O4 cathodes exhibit voltages higher than 2.5 V (vs. Mg) and a high specific energy density of 246 Wh/kg under conditions that are amenable for practical applications. The successful demonstrations reported here could be a significant step forward for practical hybrid batteries.

  15. Controlling the threshold voltage of SnO2 nanowire transistors with dual in-plane-gate structures gated by chitosan proton conductors

    Science.gov (United States)

    Liu, Huixuan; Tan, Rongri

    2017-05-01

    We fabricated novel dual in-plane-gate electric-double-layer (EDL) SnO2 nanowire transistors gated by chitosan using only one transmission electron microscopy (TEM) nickel grid mask at room temperature, and we successfully controlled its threshold voltage. By changing the second in-plane gate bias from 1.0 to -1.0 V, we tuned the threshold voltage of these transistors from -0.35 to 0.21 V. Their operation voltage was 1.0 V, because the EDL gate dielectric can lead to high gate dielectric capacitance (4.24 µF/cm2). These dual in-plane-gate nanowire transistors could pave the way to useful low-voltage nanoelectronic devices.

  16. Dual-loop control strategy for DFIG-based Wind turbines under grid voltage disturbances

    DEFF Research Database (Denmark)

    Zhu, Rongwu; Chen, Zhe; Tang, Yi

    2016-01-01

    For a multimegawatts doubly-fed induction generator (DFIG), the grid voltage disturbances may affect the stator flux and induce the transient stator flux, due to the direct connection of the stator and the grid. The accumulation of the transient stator flux caused by the variations of the stator ...

  17. Automated tube voltage selection for radiation dose and contrast medium reduction at coronary CT angiography using 3{sup rd} generation dual-source CT

    Energy Technology Data Exchange (ETDEWEB)

    Mangold, Stefanie [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Eberhard-Karls University Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany); Wichmann, Julian L. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Frankfurt (Germany); Schoepf, U.J. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Medical University of South Carolina, Division of Cardiology, Department of Medicine, Charleston, SC (United States); Poole, Zachary B.; Varga-Szemes, Akos; De Cecco, Carlo N. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Canstein, Christian [Siemens Medical Solutions, Malvern, PA (United States); Caruso, Damiano [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); University of Rome ' ' Sapienza' ' , Department of Radiological Sciences, Oncology and Pathology, Rome (Italy); Bamberg, Fabian; Nikolaou, Konstantin [Eberhard-Karls University Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany)

    2016-10-15

    To investigate the relationship between automated tube voltage selection (ATVS) and body mass index (BMI) and its effect on image quality and radiation dose of coronary CT angiography (CCTA). We evaluated 272 patients who underwent CCTA with 3{sup rd} generation dual-source CT (DSCT). Prospectively ECG-triggered spiral acquisition was performed with automated tube current selection and advanced iterative reconstruction. Tube voltages were selected by ATVS (70-120 kV). BMI, effective dose (ED), and vascular attenuation in the coronary arteries were recorded. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Five-point scales were used for subjective image quality analysis. Image quality was rated good to excellent in 98.9 % of examinations without significant differences for proximal and distal attenuation (all p ≥.0516), whereas image noise was rated significantly higher at 70 kV compared to ≥100 kV (all p <.0266). However, no significant differences were observed in SNR or CNR at 70-120 kV (all p ≥.0829). Mean ED at 70-120 kV was 1.5 ± 1.2 mSv, 2.4 ± 1.5 mSv, 3.6 ± 2.7 mSv, 5.9 ± 4.0 mSv, 7.9 ± 4.2 mSv, and 10.7 ± 4.1 mSv, respectively (all p ≤.0414). Correlation analysis showed a moderate association between tube voltage and BMI (r =.639). ATVS allows individual tube voltage adaptation for CCTA performed with 3{sup rd} generation DSCT, resulting in significantly decreased radiation exposure while maintaining image quality. (orig.)

  18. Voltage and Calcium Dual Channel Optical Mapping of Cultured HL-1 Atrial Myocyte Monolayer

    Science.gov (United States)

    Zhao, Weiwei; Fast, Vladimir G.; Ye, Tong; Ai, Xun

    2015-01-01

    Optical mapping has proven to be a valuable technique to detect cardiac electrical activity on both intact ex vivo hearts and in cultured myocyte monolayers. HL-1 cells have been widely used as a 2-Dimensional cellular model for studying diverse aspects of cardiac physiology. However, it has been a great challenge to optically map calcium (Ca) transients and action potentials simultaneously from the same field of view in a cultured HL-1 atrial cell monolayer. This is because special handling and care is required to prepare healthy cells that can be electrically captured and optically mapped. Therefore, we have developed an optimal working protocol for dual channel optical mapping. In this manuscript, we have described in detail how to perform the dual channel optical mapping experiment. This protocol is a useful tool to enhance the understanding of action potential propagation and Ca kinetics in arrhythmia development. PMID:25867896

  19. A comparative study of different transformer connections for railway power supply- mitigation of voltage unbalance

    DEFF Research Database (Denmark)

    Firat, Gurkan; Yang, Guangya; Ali Hussain Al-Ali, Haider

    2015-01-01

    The railway represents a large power consumer that can cause uneven loading of the phases in the high voltage grid. These unbalanced loads supplied by the utility may lead to voltage unbalance problems in the system and thereby affects the other consumers connected to the same network. It is fact...... that, voltage unbalance appears mainly as a result of unbalanced currents at the points of common coupling drawn by unevenly distributed loads. Because of a significant amount of negative sequence current injected to the system, the power system components will suffer from consequent negative effects...... such as overheating, additional losses of lines and transformers, interference with communication systems etc. This paper presents a comparative study of some transformer connections which commonly used in railway supplying AC traction loads, for voltage unbalance mitigations. Simulations for comparison...

  20. Front-end and high-voltage electronics developments for compact, dual ion-electron thermal measurements

    Science.gov (United States)

    Cara, A.; Lavraud, B.; Tap, H.; Ballot, Y.; Aoustin, C.; Chassela, O.; Cadu, A.; Devoto, P.; Fedorov, A.; Rouzaud, J.; Rubiella, J.; Sauvaud, J. A.; Seran, H. C.; Bernal, O.; Payan, D.; Rouzies, C.

    2015-12-01

    The Active Monitor Box of Electrostatic Risks (AMBER) is a double-head thermal electron and ion electrostatic analyzer (~0 - 30 keV) that will be launched onboard the Jason-3 spacecraft in 2015. The new generation AMBRE instrument (AMBER_NG) constitutes a significant new evolution that will be based on a single head with newly developed sub-systems to reduce all instrument resources. We will describe the main front-end and high-voltage electronics developments which are being made to perform such dual ion-electron measurements. The first purpose of AMBER_NG is the monitoring of spacecraft charging and of the plasma populations at the origin of this charging. The design is also appropriate for the study of space plasma processes in the Earth's magnetosphere, as well as at other planets where time resolution may not prevail over mass constraints.

  1. The Applications of Current Comparators in the Measurements on High Voltage Insulation

    Directory of Open Access Journals (Sweden)

    Fei Yi-jun

    2016-01-01

    Full Text Available This paper describes the basic structure of the current comparator used for high voltage insulation measurements. Further applications for the current comparator in high voltage insulation are investigated and developed. A measuring system for the measurement of harmonics in the loss current of water tree aged insulation is described, as well as the principles to measure partial discharges with the current comparator bridge. A new system for the measurement of the DC component in the leakage current of insulation is de1veloped and presented. The results of experiments on XLPE cable insulation are also given.

  2. Non-enhanced Low-tube-voltage High-pitch Dual-source Computed Tomography with Sinogram Affirmed Iterative Reconstruction Algorithm of the Abdomen and Pelvis

    Institute of Scientific and Technical Information of China (English)

    Liang Zhu

    2014-01-01

    Objective To investigate the image quality, radiation dose and diagnostic value of the low-tube-voltage high-pitch dual-source computed tomography (DSCT) with sinogram affirmed iterative reconstruction (SAFIRE) for non-enhanced abdominal and pelvic scans. Methods This institutional review board-approved prospective study included 64 patients who gave written informed consent for additional abdominal and pelvic scan with DSCT in the period from November to December 2012. The patients underwent standard non-enhanced CT scans (protocol 1) [tube voltage of 120 kVp/pitch of 0.9/filtered back-projection (FBP) reconstruction] followed by high-pitch non-enhanced CT scans (protocol 2) (100 kVp/3.0/SAFIRE). The total scan time, mean CT number, signal-to-noise ratio (SNR), image quality, lesion detectability and radiation dose were compared between the two protocols. Results The total scan time of protocol 2 was significantly shorter than that of protocol 1 (1.4±0.1 seconds vs. 7.6±0.6 seconds, P Conclusion The high-pitch DSCT with SAFIRE can shorten scan time and reduce radiation dose while preserving image quality in non-enhanced abdominal and pelvic scans.

  3. Single-portal-phase low-tube-voltage dual-energy CT for short-term follow-up of acute pancreatitis: evaluation of CT severity index, interobserver agreement and radiation dose

    Energy Technology Data Exchange (ETDEWEB)

    Wichmann, Julian L. [University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Frankfurt am Main (Germany); Universitaetsklinikum Frankfurt, Institut fuer Diagnostische und Interventionelle Radiologie, Frankfurt am Main (Germany); Majenka, Pawel; Beeres, Martin; Kromen, Wolfgang; Schulz, Boris; Bauer, Ralf W.; Kerl, J.M.; Gruber-Rouh, Tatjana; Hammerstingl, Renate; Vogl, Thomas J.; Lehnert, Thomas [University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Frankfurt am Main (Germany); Wesarg, Stefan [Fraunhofer IGD, Cognitive Computing and Medical Imaging, Darmstadt (Germany)

    2014-11-15

    To intra-individually compare single-portal-phase low-tube-voltage (100-kVp) computed tomography (CT) with 120-kVp images for short-term follow-up assessment of CT severity index (CTSI) of acute pancreatitis, interobserver agreement and radiation dose. We retrospectively analysed 66 patients with acute pancreatitis who underwent initial dual-contrast-phase CT (unenhanced, arterial, portal phase) at admission and short-term (mean interval 11.4 days) follow-up dual-contrast-phase dual-energy CT. The 100-kVp and linearly blended images representing 120-kVp acquisition follow-up CT images were independently evaluated by three radiologists using a modified CTSI assessing pancreatic inflammation, necrosis and extrapancreatic complications. Scores were compared with paired t test and interobserver agreement was evaluated using intraclass correlation coefficients (ICC). Mean CTSI scores on unenhanced, portal- and dual-contrast-phase images were 4.9, 6.1 and 6.2 (120 kVp) and 5.0, 6.0 and 6.1 (100 kVp), respectively. Contrast-enhanced series showed a higher CTSI compared to unenhanced images (P < 0.05) but no significant differences between single- and dual-contrast-phase series (P > 0.7). CTSI scores were comparable for 100-kVp and 120-kVp images (P > 0.05). Interobserver agreement was substantial for all evaluated series and subcategories (ICC 0.67-0.93). DLP of single-portal-phase 100-kVp images was reduced by 41 % compared to 120-kVp images (363.8 versus 615.9 mGy cm). Low-tube-voltage single-phase 100-kVp CT provides sufficient information for follow-up evaluation of acute pancreatitis and significantly reduces radiation exposure. (orig.)

  4. FPGA-based voltage and current dual drive system for high frame rate electrical impedance tomography.

    Science.gov (United States)

    Khan, Shadab; Manwaring, Preston; Borsic, Andrea; Halter, Ryan

    2015-04-01

    Electrical impedance tomography (EIT) is used to image the electrical property distribution of a tissue under test. An EIT system comprises complex hardware and software modules, which are typically designed for a specific application. Upgrading these modules is a time-consuming process, and requires rigorous testing to ensure proper functioning of new modules with the existing ones. To this end, we developed a modular and reconfigurable data acquisition (DAQ) system using National Instruments' (NI) hardware and software modules, which offer inherent compatibility over generations of hardware and software revisions. The system can be configured to use up to 32-channels. This EIT system can be used to interchangeably apply current or voltage signal, and measure the tissue response in a semi-parallel fashion. A novel signal averaging algorithm, and 512-point fast Fourier transform (FFT) computation block was implemented on the FPGA. FFT output bins were classified as signal or noise. Signal bins constitute a tissue's response to a pure or mixed tone signal. Signal bins' data can be used for traditional applications, as well as synchronous frequency-difference imaging. Noise bins were used to compute noise power on the FPGA. Noise power represents a metric of signal quality, and can be used to ensure proper tissue-electrode contact. Allocation of these computationally expensive tasks to the FPGA reduced the required bandwidth between PC, and the FPGA for high frame rate EIT. In 16-channel configuration, with a signal-averaging factor of 8, the DAQ frame rate at 100 kHz exceeded 110 frames s (-1), and signal-to-noise ratio exceeded 90 dB across the spectrum. Reciprocity error was found to be for frequencies up to 1 MHz. Static imaging experiments were performed on a high-conductivity inclusion placed in a saline filled tank; the inclusion was clearly localized in the reconstructions obtained for both absolute current and voltage mode data.

  5. Dual branch high voltage pulse generator for the beam extraction of the Large Hadron Collider

    CERN Document Server

    Bonthond, J; Ducimetière, L; Jansson, U; Vossenberg, Eugène B

    2002-01-01

    The LHC beam extraction kicker system, MKD, is composed of 15 fast kicker magnets per beam to extract the particles in one turn from the collider and to dispose them, after dilution, on an external absorber. Each magnet is powered by a separate pulse generator. The original single branch generator consisted of a discharge capacitor in series with a solid state closing switch left bracket 1 right bracket operating at 30 kV. In combination with a parallel freewheel diode stack this generator produced a current pulse of 2.7 mus rise time, 18.5 kA amplitude and about 1.8 ms fall time, of which only about 90 mus are needed to dump the beam. The freewheel diode circuit is equipped with a flat top current droop compensation network, consisting of a low voltage, low stray inductance, high current discharge capacitor. Extensive reliability studies have meanwhile suggested to further increase the operational safety of this crucial system by equipping each generator with two parallel branches. This paper presents the re...

  6. A dual-energy medical instrument for measurement of x-ray source voltage and dose rate

    Science.gov (United States)

    Ryzhikov, V. D.; Naydenov, S. V.; Volkov, V. G.; Opolonin, O. D.; Makhota, S.; Pochet, T.; Smith, C. F.

    2016-03-01

    An original dual-energy detector and medical instrument have been developed to measure the output voltages and dose rates of X-ray sources. Theoretical and experimental studies were carried out to characterize the parameters of a new scintillator-photodiode sandwich-detector based on specially-prepared zinc selenide crystals in which the low-energy detector (LED) works both as the detector of the low-energy radiation and as an absorption filter allowing the highenergy fraction of the radiation to pass through to the high-energy detector (HED). The use of the LED as a low-energy filter in combination with a separate HED opens broad possibilities for such sandwich structures. In particular, it becomes possible to analyze and process the sum, difference and ratio of signals coming from these detectors, ensuring a broad (up to 106) measurement range of X-ray intensity from the source and a leveling of the energy dependence. We have chosen an optimum design of the detector and the geometry of the component LED and HED parts that allow energy-dependence leveling to within specified limits. The deviation in energy dependence of the detector does not exceed about 5% in the energy range from 30 to 120 keV. The developed detector and instrument allow contactless measurement of the anode voltage of an X-ray emitter from 40 to 140 kV with an error no greater than 3%. The dose rate measurement range is from 1 to 200 R/min. An original medical instrument has passed clinical testing and was recommended for use in medical institutions for X-ray diagnostics.

  7. Multi-Purpose Low Voltage Dual Output DC-DC Converter For 100V Power Bus Telecom Platform

    Science.gov (United States)

    Galiana, D.; Mollard, J. M.

    2011-10-01

    The decreasing supply voltages of digital electronic and high speed ADC (Analog to Digital Converter) and DAC (Digital to Analog Converter) require flexible and high current secondary power distribution system. In the frame of the Inmarsat I-XL program, a 12 kW geomobile SatCom satellite, with 100 V regulated power bus, a multi purpose dual output converter was developed for the payload processor as a building block. After a short introduction on the main performance requirements, the baseline architecture is presented. The main drivers of the architecture are reliability, adjustability, radiation tolerant and single event free, volume and mass. The combination of all these constraints highlights the need of significant breakthrough in various domains. Many research results related to packaging and power electronic topics are brought up. These results directly drive the adopted solution presented in the next step followed by a description of the integration of the defined building block in the Inmarsat I-XL payload IP (Integrated Processor). Finally, the main electrical performances such as output ripple and spikes, load step transient and stability are summarized.

  8. Advanced design methodology for single and dual voltage wound core power transformers based on a particular finite element model

    Energy Technology Data Exchange (ETDEWEB)

    Tsili, Marina A.; Kladas, Antonios G. [Faculty of Electrical & amp; Computer Engineering, National Technical University of Athens, GR-15780, Athens (Greece); Georgilakis, Pavlos S. [Department of Production Engineering and Management, Technical University of Crete, GR-73100, Chania (Greece); Souflaris, Athanasios T.; Paparigas, Dimitris G. [Schneider Electric AE, Elvim Plant, GR-32011, Inofyta, Viotia (Greece)

    2006-06-15

    The paper presents an accurate and cost effective three-dimensional finite element model for the analysis and design of wound core, shell type, power transformers, focusing on the short-circuit impedance evaluation. The model efficiency lies on the detailed representation of the transformer geometry along with the adoption of a particular reduced scalar potential formulation enabling three-dimensional magnetostatic problem solution without prior source field calculation. Its accuracy is validated through local field measurements and through comparison of the calculated short-circuit impedance value with the measured one for several commercial wound core, shell type transformers. In such transformers, involving extensive winding parts out of the core window, the detailed representation of the transformer geometry, including the winding cooling ducts, provides accurate results for low densities of the three-dimensional finite element mesh, resulting to reduction of the required calculation time. The model is used in the development of a computational tool, which enables the automated and accurate transformer characteristics prediction, adopted to the manufacturing process. This tool has also been applied in the impedance calculation for different winding connections of dual voltage transformers, thus providing the information needed for the achievement of an accurate design and the enhancement of the manufacturer's ability to reduce design margins. The methodology presented in this paper has been incorporated in the design process of a transformer manufacturing industry. (author)

  9. Nonword reading: comparing dual-route cascaded and connectionist dual-process models with human data.

    Science.gov (United States)

    Pritchard, Stephen C; Coltheart, Max; Palethorpe, Sallyanne; Castles, Anne

    2012-10-01

    Two prominent dual-route computational models of reading aloud are the dual-route cascaded (DRC) model, and the connectionist dual-process plus (CDP+) model. While sharing similarly designed lexical routes, the two models differ greatly in their respective nonlexical route architecture, such that they often differ on nonword pronunciation. Neither model has been appropriately tested for nonword reading pronunciation accuracy to date. We argue that empirical data on the nonword reading pronunciation of people is the ideal benchmark for testing. Data were gathered from 45 Australian-English-speaking psychology undergraduates reading aloud 412 nonwords. To provide contrast between the models, the nonwords were chosen specifically because DRC and CDP+ disagree on their pronunciation. Both models failed to accurately match the experiment data, and both have deficiencies in nonword reading performance. However, the CDP+ model performed significantly worse than the DRC model. CDP++, the recent successor to CDP+, had improved performance over CDP+, but was also significantly worse than DRC. In addition to highlighting performance shortcomings in each model, the variety of nonword responses given by participants points to a need for models that can account for this variety.

  10. A comparative study of the action of tolperisone on seven different voltage dependent sodium channel isoforms.

    Science.gov (United States)

    Hofer, Doris; Lohberger, Birgit; Steinecker, Bibiane; Schmidt, Kurt; Quasthoff, Stefan; Schreibmayer, Wolfgang

    2006-05-24

    The specific, acute interaction of tolperisone, an agent used as a muscle relaxant and for the treatment of chronic pain conditions, with the Na(v1.2), Na(v1.3), Na(v1.4), Na(v1.5), Na(v1.6), Na(v1.7), and Na(v1.8) isoforms of voltage dependent sodium channels was investigated and compared to that of lidocaine. Voltage dependent sodium channels were expressed in the Xenopus laevis oocyte expression system and sodium currents were recorded with the two electrode voltage clamp technique. Cumulative dose response relations revealed marked differences in IC(50) values between the two drugs on identical isoforms, as well as between isoforms. A detailed kinetic analysis uncovered that tolperisone as well as lidocaine exhibited their blocking action not only via state dependent association/dissociation with voltage dependent sodium channels, but a considerable fraction of inhibition is tonic, i.e. permanent and basic in nature. Voltage dependent activation was affected to a minor extent only. A shift in steady-state inactivation to more negative potentials could be observed for most drug/isoform combinations. The contribution of this shift to overall block was, however, small at drug concentrations resulting in considerable overall block. Recovery from inactivation was affected notably by both drugs. Lidocaine application led to a pronounced prolongation of the time constant of the fast recovery process for the Na(v1.3), Na(v1.5), and Na(v1.7) isoforms, indicating common structural properties in the local anesthetic receptor site of these three proteins. Interestingly, this characteristic drug action was not observed for tolperisone.

  11. Comparative Study of Breakdown Voltage of Mineral, Synthetic and Natural Oils and Based Mineral Oil Mixtures under AC and DC Voltages

    Directory of Open Access Journals (Sweden)

    Abderrahmane Beroual

    2017-04-01

    Full Text Available This paper deals with a comparative study of AC and DC breakdown voltages of based mineral oil mixtures with natural and synthetic esters mainly used in high voltage power transformers. The goal was to analyze the performances of oil mixtures from the dielectric withstand point of view and to predict the behavior of transformers originally filled with mineral oil and re-filled with synthetic or natural ester oils when emptied for maintenance. The study concerns mixtures based on 20%, 50%, and 80% of natural and synthetic ester oils. AC breakdown voltages were measured using a sphere-sphere electrode system according to IEC 60156 specifications; the same specification was adopted for DC measurements since there is no standard specifications for this voltage waveform. A statistical analysis of the mean values, standard deviations, and histograms of breakdown voltage data was carried out. The Normal and Weibull distribution functions were used to analyze the experimental data and the best function that the data followed was used to estimate the breakdown voltage with risk of 1%, 10%, and 50% probability. It was shown that whatever the applied voltage waveforms, ester oils always have a significantly higher breakdown voltage than mineral oil. The addition of only 20% of natural or synthetic ester oil was sufficient to considerably increase the breakdown voltage of mineral oil. The dielectric strength of such a mixture is much higher than that of mineral oil alone and can reach that of ester oils. From the point of view of dielectric strength, the mixtures constitute an option for improving the performance of mineral oil. Thus, re-filling of transformers containing up to 20% mineral oil residues with ester oils, does not present any problem; it is even advantageous when considering only the breakdown voltage. Under AC, the mixtures with natural ester always follow the behavior of vegetable oil alone. With the exception of the 20% mixture of natural

  12. Comparing and evaluating the voltage regulation of a UPFC and STATCOM

    Energy Technology Data Exchange (ETDEWEB)

    Al-Mawsawi, S.A. [University of Bahrain (Bahrain). College of Engineering

    2003-11-01

    In recent years it has been illustrated that the installation position of a Unified power flow controller (UPFC) has an important effect on its overall performance. A pulse width modulation (PWM) based UPFC used as a voltage regulator is modeled and analyzed to investigate its optimal position in the transmission line. This is compared with STATic COMpensator (STATCOM) device. This paper deals with the definition and simulation of the steady-state performance of the UPFC and STATCOM when they operate as a terminal voltage regulator. From the simulation results it is demonstrated that by varying the modulation index of the two devices it can control the distribution of active and reactive power flows. Furthermore, the comparisons for the optimum operation for the two devices have been performed. (author)

  13. Design of a Low Voltage low Power Double tail comparator in 180nm cmos Technology

    Directory of Open Access Journals (Sweden)

    Mr. Deepak Joseph Babu

    2014-09-01

    Full Text Available The need of analog to digital converters with ultra low power, area efficient and high speed is giving more chance to the use of dynamic regenerative comparators to maximize the speed and power efficiency. In this paper, an analysis on the delay and power of the dynamic comparators will be presented and based on the presented analysis, a new dynamic comparator is proposed, in which the conventional double tail comparator is modified for low power and fast operation even in small supply voltages. Here by adding a few transistors, the power consumptions can be reduced drastically. Post–layout simulation using 180nm CMOS technology confirms the analysis results of the proposed dynamic comparator.

  14. Comparing the da Vinci si single console and dual console in teaching novice surgeons suturing techniques.

    Science.gov (United States)

    Crusco, Salvatore; Jackson, Tiffany; Advincula, Arnold

    2014-01-01

    Robot-assisted laparoscopic surgery is often taught with the surgical mentor at the surgeon console and the trainee at the patient's bedside. The da Vinci dual console (Intuitive Surgical, Sunnyvale, California) allows a surgical mentor to teach with both the mentor and the trainee working at a surgeon console simultaneously. The purpose of this study is to evaluate the effectiveness of the dual console versus the single console for teaching medical students robotic tasks. Forty novice medical students were randomized to either the da Vinci single-console or dual-console group and were taught 4 knot-tying techniques by a surgical mentor. The students were timed while performing the tasks. No statistically significant differences in mean task times were observed between the single- and dual-console groups: interrupted stitch with a 2-handed knot (300 seconds for single vs 294 seconds for dual, P=.59), interrupted stitch with a 1-handed knot (198 seconds for single vs 212 seconds for dual, P=.88), figure-of-8 stitch with a 2-handed knot (261 seconds for single vs 219 seconds for dual, P=.20), and figure-of-8 stitch with a 1-handed knot (200 seconds for single vs 199 seconds for dual, P=.53). No significant difference was observed in performance time when teaching knot-tying techniques to medical students using the da Vinci dual console compared with the single console. More research needs to be performed on the utility of the da Vinci dual console in surgical training.

  15. Comparative Studies of Different Control Strategies of a Dynamic Voltage Restorer Based on Matrix Converter

    Directory of Open Access Journals (Sweden)

    Amin Shabanpour

    2012-01-01

    Full Text Available A dynamic voltage restorer (DVR with no energy storage is studied. By using a matrix converter instead of the conventional AC/DC/AC converters, elimination of the DC-link capacitor is possible. The switching algorithm of matrix converter is the space vector modulation. There are different compensation algorithms to control the conventional DVR. These methods have been analyzed in this paper for the proposed matrix-converter-based DVR. A deep analysis through different diagrams would show the advantages or disadvantages of each compensation method. Equations for all methods are derived, and the characteristics of algorithms are compared with each other.

  16. Design of 6-Bit Flash Analog to Digital Converter Using Variable Switching Voltage CMOS Comparator

    Directory of Open Access Journals (Sweden)

    Gulrej Ahmed

    2014-04-01

    Full Text Available This paper presents the design of 6-bit flash analog to digital Converter (ADC using the new variable switching voltage (VSV comparator. In general, Flash ADCs attain the highest conversion speed at the cost of high power consumption. By using the new VSV comparator, the designed 6-bit Flash ADC exhibits significant improvement in terms of power and speed of previously reported Flash ADCs. The simulation result shows that the converter consumes peak power 2.1 mW from a 1.2 V supply and achieves the speed of 1 GHz in a 65nm standard CMOS process. The measurement of maximum differential and integral nonlinearities (DNL and INL of the Flash ADC are 0.3 LSB and 0.6 LSB respectively.

  17. Impact of Dual Task on Parkinson's Disease, Stroke and Ataxia Patients' Gait: A Comparative Analysis

    Directory of Open Access Journals (Sweden)

    Michelly Arjona Maciel

    2014-01-01

    Full Text Available Introduction: Performing dual task for neurological patients is complex and it can be influenced by the localization of the neurological lesion. Objective: Comparing the impact of dual task on gait in patients with Parkinson's disease, stroke and ataxia. Method: Subjects with Parkinson's disease (PD in initial phase, stroke and ataxia, with independent gait, were evaluated while doing simple gait, with cognitive, motor and cognitive-motor gait demand, assessing average speed and number of steps. Results: Ataxia and stroke patients, compared with PD, showed an increase in the number of steps and decrease the average speed on the march with cognitive demand. Subjects with PD performed better on tasks when compared to others. Conclusion: In this study the impact of dual task was lower in Parkinson's disease patients.

  18. Discrete iterative-map mo deling and dynamical analysis of digital voltage-mo de controlled buck converter with dual-edge mo dulation%基于双缘调制的数字电压型控制Buck变换器离散迭代映射建模与动力学分析∗

    Institute of Scientific and Technical Information of China (English)

    刘啸天; 周国华; 李振华; 陈兴

    2015-01-01

    The operation principle of digital voltage-mode controlled buck converter with dual-edge modulation is analyzed in this paper. Based on the state equation of buck converter and six possible evolutions in one switching cycle, the discrete iterative-map model of digital voltage-mode controlled buck converter with dual-edge modulation is established. Ignoring the quantization error of analog-digital converter and on the basis of its discrete iterative-map model, the nonlinear dynamical behavior of digital voltage-mode controlled buck converter with dual-edge modulation is investigated in detail. Taking the input voltage and the load resistance as bifurcation parameters, the output voltage bifurcation diagram and the inductor current bifurcation diagram are plotted. Through analyzing the bifurcation diagrams, it is indicated that there are two kinds of similar but different Hopf bifurcation phenomena. By use of Poincar´e section, time-domain simulation waveforms and phase portraits, two different Hopf bifurcations and low-frequency oscillation phenomena are compared and studied. Observing the inductor current and capacitor voltage waveforms respectively, it is obviously found that their oscillation frequencies and amplitudes are different, the shapes of two Poincar´e sections and phase portraits are also different. In order to verify the correctness of the simulation and theoretical analysis, the eigenvalues of Jacobian matrix of the discrete iterative map model are introduced and solved in two kinds of stable evolutions. Through analyzing variation of eigenvalues of Jacobi matrix with input voltage, the existence and difference of two kinds of Hopf bifurcation phenomena are proved theoretically. Moreover, it is observed in this paper that the odd period-doubling bifurcation phenomenon exists in digital voltage-mode controlled buck converter with dual-edge modulation for the first time, where the operation state of the buck converter turns from period-one into period

  19. Single- and dual-wavelength photodetectors with MgZnO/ZnO metal-semiconductor-metal structure by varying the bias voltage

    Science.gov (United States)

    Hwang, J. D.; Lin, G. S.

    2016-09-01

    By varying the bias voltage of an Mg x Zn1-x O/ZnO metal-semiconductor-metal photodetector (MSM-PDs), the detection wavelength can be modulated from a single to a dual wavelength. A long-wavelength band response is caused by the ZnO absorption and a short-wavelength band response is caused by Mg x Zn1-x O. At a 0 V bias voltage, the photogenerated electrons in ZnO are confined to the Mg x Zn1-x O/ZnO interface, arising from the piezoelectric polarization. The accumulated electrons hop the Mg x Zn1-x O layer through the assistance of defects; however, the photogenerated electrons in Mg x Zn1-x O cannot cross over the large barrier height at the Au/MgZnO interface, resulting in a single-wavelength photodetector with a long-wavelength band (345-400 nm) having a peak wavelength of 370 nm. By increasing the bias voltage to 1-2 V, the barrier height is lowered, enabling the photogenerated electrons in Mg x Zn1-x O to easily cross over the low barrier height, leading to dual-wavelength photodetectors having peak wavelengths of 370 and 340 nm. On further increasing the bias voltage beyond 2 V, the photogenerated electrons in ZnO sink deeply in the hollow at the Mg x Zn1-x O/ZnO interface owing to the large applied voltage. These electrons are effectively confined at the Mg x Zn1-x O/ZnO interface, which retards the tunneling of the photogenerated electrons in ZnO through the Mg x Zn1-x O layer; hence the MSM-PDs revert back to single wavelength photodetectors; however, the detection wavelength is different from that of the MSM-PDs biased at 0 V. Instead of having a long-wavelength band (345-400 nm), the MSM-PDs demonstrate a short-wavelength band (320-345 nm) at a 3 V bias voltage.

  20. [Comparative pharmacophore analysis of dual dopamine D2/5-HT(2A) receptor antagonists].

    Science.gov (United States)

    Guo, Yan-shen; Guo, Zong-ru

    2009-03-01

    Dual dopamine D2/5-HT2A receptor antagonists have potent activity and are referred to atypical antipsychotics due to their lower propensity to elicit EPS and their moderate efficacy toward negative symptoms. However, an on-going challenge in developing atypical antipsychotics drugs is to maintain the favorable profiles and avoid of cardiovascular risk. In this paper, comparative pharmacophore analysis of dual dopamine D2/5-HT2A receptor antagonists, hERG K+ channel blockers, and alA adrenoceptor antagonists is carried out, and the results could give some insight into multi-target drug design.

  1. The architecture design of a 2mW 18-bit high speed weight voltage type DAC based on dual weight resistance chain

    Institute of Scientific and Technical Information of China (English)

    Chen Qixing; Luo Qiyu

    2013-01-01

    At present,the architecture of a digital-to-analog converter (DAC) in essence is based on the weight current,and the average value of its D/A signal current increases in geometric series according to its digital signal bits increase,which is 2n-1 times of its least weight current.But for a dual weight resistance chain type DAC,by using the weight voltage manner to D/A conversion,the D/A signal current is fixed to chain current Icha; it is only 1/2n-1 order of magnitude of the average signal current value of the weight current type DAC.Its principle is:n pairs dual weight resistances form a resistance chain,which ensures the constancy of the chain current; if digital signals control the total weight resistance from the output point to the zero potential point,that could directly control the total weight voltage of the output point,so that the digital signals directly turn into a sum of the weight voltage signals; thus the following goals are realized:(1) the total current is less than 200 μA; (2) the total power consumption is less than 2 mW; (3) an 18-bit conversion can be realized by adopting a multi-grade structure; (4) the chip area is one order of magnitude smaller than the subsection current-steering type DAC; (5) the error depends only on the error of the unit resistance,so it is smaller than the error of the subsection current-steering type DAC;(6) the conversion time is only one action time of switch on or off,so its speed is not lower than the present DAC.

  2. Atmospheric Pressure Ionization Using a High Voltage Target Compared to Electrospray Ionization

    Science.gov (United States)

    Lubin, Arnaud; Bajic, Steve; Cabooter, Deirdre; Augustijns, Patrick; Cuyckens, Filip

    2016-11-01

    A new atmospheric pressure ionization (API) source, viz. UniSpray, was evaluated for mass spectrometry (MS) analysis of pharmaceutical compounds by head-to-head comparison with electrospray ionization (ESI) on the same high-resolution MS system. The atmospheric pressure ionization source is composed of a grounded nebulizer spraying onto a high voltage, cylindrical stainless steel target. Molecules are ionized in a similar fashion to electrospray ionization, predominantly producing protonated or deprotonated species. Adduct formation (e.g., proton and sodium adducts) and in-source fragmentation is shown to be almost identical between the two sources. The performance of the new API source was compared with electrospray by infusion of a mix of 22 pharmaceutical compounds with a wide variety of functional groups and physico-chemical properties (molecular weight, logP, and pKa) in more than 100 different conditions (mobile phase strength, solvents, pH, and flow rate). The new API source shows an intensity gain of a factor 2.2 compared with ESI considering all conditions on all compounds tested. Finally, some hypotheses on the ionization mechanism, similarities, and differences with ESI, are discussed.

  3. On-chip frequency compensation with a dual signal path operational transconductance amplifier for a voltage mode control DC/DC converter

    Science.gov (United States)

    Qiang, Ye; Jie, Liu; Bing, Yuan; Xinquan, Lai; Ning, Liu

    2012-04-01

    A novel on-chip frequency compensation circuit for a voltage-mode control DC/DC converter is presented. By employing an RC network in the two signal paths of an operational transconductance amplifier (OTA), the proposed circuit generates two zeros to realize high closed-loop stability. Meanwhile, full on-chip integration is also achieved due to its simple structure. Hence, the number of off-chip components and the board space is greatly reduced. The structure of the dual signal path OTA is also optimized to help get a better transition response. Implemented in a 0.5 μm CMOS process, the voltage mode control DC/DC converter with the proposed frequency compensation circuit exhibits good stability. The test results show that both load and line regulations are less than 0.3%, and the output voltage can be recovered within 15 μs for a 400 mA load step. Moreover, the compensation components area is less than 2% of the die's area and the board space is also reduced by 11%. The efficiency of the whole chip can be up to 95%.

  4. Comparative Analysis of PWM Techniques for Three Level Diode Clamped Voltage Source Inverter

    Directory of Open Access Journals (Sweden)

    Zulkifilie Bin Ibrahim

    2014-07-01

    Full Text Available Multilevel inverters are increasingly being used in high-power medium voltage industrial drive applications due to their superior performance compared to conventional two-level inverters. Thre are a number of Pulse width modulation (PWM techniques applied in recent years. The most widely applied PWM techniques are Sine Pulse Width Modulation (SPWM and Space Vector Pulse Width Modulation (SVPWM.  SPWM is the most simple modulation technique that can realize easily in analog circuit.  However, it has some drawbacks such as higher total harmonic distortion (THD, lower effective DC utilization and lower switching frequency. Space vector pulse width modulation (SVPWM is widely used because of their easier digital realization and better DC bus utilization and lower THD. The complexity is due to the difficulty in determining the reference vector location, on times calculation, and switching states selection. This paper presents a simple SVPWM algorithm for diode clamped three level inverters based on standard two-level SVPWM which can easily determine the location of reference vector, calculate the on-times, the selection of switching states. Three level diode clamped inverter (3LDCI using space vector modulation technique has been modeled and simulated using MATLAB/SIMULINK and Origin 6.1 with a passive R-L load that can be extended to any level. Simulation results are presented to verify the proposed SVPWM control in terms of THD. The results are compared with conventional sinusoidal pulse width modulation (SPWM where SVPWM shows better performance than SPWM in terms of THD.

  5. Diagnostic accuracy of coronary CT angiography using 3{sup rd}-generation dual-source CT and automated tube voltage selection: Clinical application in a non-obese and obese patient population

    Energy Technology Data Exchange (ETDEWEB)

    Mangold, Stefanie [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Eberhard-Karls University Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany); Wichmann, Julian L. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Frankfurt (Germany); Schoepf, U.J. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Medical University of South Carolina, Division of Cardiology, Department of Medicine, Charleston, SC (United States); Caruso, Damiano [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); University of Rome ' ' Sapienza' ' , Department of Radiological Sciences, Oncology and Pathology, Rome (Italy); Tesche, Christian [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Heart Centre Munich-Bogenhausen, Department of Cardiology, Munich (Germany); Steinberg, Daniel H.; Bayer, Richard R. [Medical University of South Carolina, Division of Cardiology, Department of Medicine, Charleston, SC (United States); Varga-Szemes, Akos; Stubenrauch, Andrew C.; Biancalana, Matthew; De Cecco, Carlo N. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Nikolaou, Konstantin [Eberhard-Karls University Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany)

    2017-06-15

    To investigate diagnostic accuracy of 3{sup rd}-generation dual-source CT (DSCT) coronary angiography in obese and non-obese patients. We retrospectively analyzed 76 patients who underwent coronary CT angiography (CCTA) and invasive coronary angiography. Prospectively ECG-triggered acquisition was performed with automated tube voltage selection (ATVS). Patients were dichotomized based on body mass index in groups A (<30 kg/m{sup 2}, n = 37) and B (≥30 kg/m{sup 2}, n = 39) and based on tube voltage in groups C (<120 kV, n = 46) and D (120 kV, n = 30). Coronary arteries were assessed for significant stenoses (≥50 % luminal narrowing) and diagnostic accuracy was calculated. Per-patient overall sensitivity, specificity, positive predictive value, negative predictive value (NPV) and accuracy were 96.9 %, 95.5 %, 93.9 %, 97.7 % and 96.1 %, respectively. Sensitivity and NPV were lower in groups B and D compared to groups A and C, but no statistically significant differences were observed (group A vs. B: sensitivity, 100.0 % vs. 93.3 %, p = 0.9493; NPV, 100 % vs. 95.5 %, p = 0.9812; group C vs. D: sensitivity, 100.0 % vs. 92.3 %, p = 0.8462; NPV, 100.0 % vs. 94.1 %, p = 0.8285). CCTA using 3{sup rd}-generation DSCT and (ATVS) provides high diagnostic accuracy in both non-obese and obese patients. (orig.)

  6. Dual regulation of the native ClC-K2 chloride channel in the distal nephron by voltage and pH.

    Science.gov (United States)

    Pinelli, Laurent; Nissant, Antoine; Edwards, Aurélie; Lourdel, Stéphane; Teulon, Jacques; Paulais, Marc

    2016-09-01

    ClC-K2, a member of the ClC family of Cl(-) channels and transporters, forms the major basolateral Cl(-) conductance in distal nephron epithelial cells and therefore plays a central role in renal Cl(-) absorption. However, its regulation remains largely unknown because of the fact that recombinant ClC-K2 has not yet been studied at the single-channel level. In the present study, we investigate the effects of voltage, pH, Cl(-), and Ca(2+) on native ClC-K2 in the basolateral membrane of intercalated cells from the mouse connecting tubule. The ∼10-pS channel shows a steep voltage dependence such that channel activity increases with membrane depolarization. Intracellular pH (pHi) and extracellular pH (pHo) differentially modulate the voltage dependence curve: alkaline pHi flattens the curve by causing an increase in activity at negative voltages, whereas alkaline pHo shifts the curve toward negative voltages. In addition, pHi, pHo, and extracellular Ca(2+) strongly increase activity, mainly because of an increase in the number of active channels with a comparatively minor effect on channel open probability. Furthermore, voltage alters both the number of active channels and their open probability, whereas intracellular Cl(-) has little influence. We propose that changes in the number of active channels correspond to them entering or leaving an inactivated state, whereas modulation of open probability corresponds to common gating by these channels. We suggest that pH, through the combined effects of pHi and pHo on ClC-K2, might be a key regulator of NaCl absorption and Cl(-)/HCO3 (-) exchange in type B intercalated cells.

  7. Dual-energy compared to single-energy CT in pediatric imaging: a phantom study for DECT clinical guidance

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Xiaowei; Servaes, Sabah; Darge, Kassa [The Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States); University of Pennsylvania, The Perelman School of Medicine, Philadelphia, PA (United States); McCullough, William P. [University of Virginia Health System, Department of Radiology and Medical Imaging, Charlottesville, VA (United States); Mecca, Patricia [The Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States)

    2016-11-15

    Dual-energy CT technology is available on scanners from several vendors and offers significant advantages over classic single-energy CT technology in multiple clinical applications. Many studies have detailed dual-energy CT applications in adults and several have evaluated the relative radiation dose performance of dual-energy CT in adult imaging. However, little has been published on dual-energy CT imaging in the pediatric population, and the relative dose performance of dual-energy CT imaging in the pediatric population is not well described. When evaluating dual-energy CT technology for implementation into a routine clinical pediatric imaging practice, the radiation dose implications must be considered, and when comparing relative CT dose performance, image quality must also be evaluated. Therefore the purpose of this study is to develop dual-energy CT scan protocols based on our optimized single-energy scan protocols and compare the dose. We scanned the head, chest and abdomen regions of pediatric-size anthropomorphic phantoms with contrast inserts, using our optimized single-energy clinical imaging protocols on a Siemens Flash {sup registered} CT scanner. We then scanned the phantoms in dual-energy mode using matching image-quality reference settings. The effective CT dose index volume (CTDI{sub vol}) of the scans was used as a surrogate for relative dose in comparing the single- and dual-energy scans. Additionally, we evaluated image quality using visual assessment and contrast-to-noise ratio. Dual-energy CT scans of the head and abdomen were dose-neutral for all three phantoms. Dual-energy CT scans of the chest showed a relative dose increase over the single-energy scan for 1- and 5-year-old child-based age-equivalent phantoms, ranging 11-20%. Quantitative analysis of image quality showed no statistically significant difference in image quality between the single-energy and dual-energy scans. There was no clinically significant difference in image quality by

  8. Comparative Study of Si and SiC MOSFETs for High Voltage Class D Audio Amplifiers

    DEFF Research Database (Denmark)

    Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.

    2014-01-01

    Silicon (Si) Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) are traditional utilised in class D audio amplifiers. It has been proposed to replace the traditional inefficient electrodynamic transducer with the electrostatic transducer. This imposes new high voltage requirements...... on the MOSFETs of class D amplifiers, and significantly reduces the selection of suitable MOSFETs. As a consequence it is investigated, if Silicon-Carbide (SiC) MOSFETs could represent a valid alternative. The theory of pulse timing errors are revisited for the application of high voltage and capactive loaded...... class D amplifiers. It is shown, that SiC MOSFETs can compete with Si MSOFETs in terms of THD. Validation is done using simulations and a 500 V amplifier driving a 100 nF load. THD+N below 0.3 % is reported...

  9. Comparative study of high voltage bushing designs suitable for apparatus containing cryogenic helium gas

    Science.gov (United States)

    Rodrigo, H.; Graber, L.; Kwag, D. S.; Crook, D. G.; Trociewitz, B.

    2013-10-01

    The high voltage bushing forms a critical part of any termination on cables, transformers and other power system devices. Cryogenic entities such as superconducting cables or fault current limiters add more complexity to the design of the bushing. Even more complex are bushings designed for superconducting devices which are cooled by high pressure helium gas. When looking for a bushing suitable for dielectric cable tests in a helium gas cryostat no appropriate device could be found that fulfilled the criterion regarding partial discharge inception voltage level. Therefore we decided to design and manufacture a bushing in-house. In the present work we describe the dielectric tests and operational experience on three types of bushings: One was a modified commercially available ceramics feed through which we adopted for our special need. The second bushing was made of an epoxy resin, with an embedded copper squirrel cage arrangement at the flange, extending down about 30 cm into the cold end of the bushing. This feature reduced the electric field on the surface of the bushing to a negligible value. The third bushing was based on a hollow body consisting of glass fiber reinforced polymer and stainless steel filled with liquid nitrogen. The measurements showed that the dielectric quality of all three bushings exceeded the requirements for the intended purpose. The partial discharge (PD) data from these studies will be used for the design and fabrication of a cable termination for a specialized application on board a US Navy ship.

  10. Comparative Study of Online Open Circuit Voltage Estimation Techniques for State of Charge Estimation of Lithium-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Hicham Chaoui

    2017-04-01

    Full Text Available Online estimation techniques are extensively used to determine the parameters of various uncertain dynamic systems. In this paper, online estimation of the open-circuit voltage (OCV of lithium-ion batteries is proposed by two different adaptive filtering methods (i.e., recursive least square, RLS, and least mean square, LMS, along with an adaptive observer. The proposed techniques use the battery’s terminal voltage and current to estimate the OCV, which is correlated to the state of charge (SOC. Experimental results highlight the effectiveness of the proposed methods in online estimation at different charge/discharge conditions and temperatures. The comparative study illustrates the advantages and limitations of each online estimation method.

  11. Dual phase TiO(x)N(y)/TiN charge trapping layer for low-voltage and high-speed flash memory application.

    Science.gov (United States)

    Zhang, Gang; Yoo, Won Jong

    2009-12-01

    Flash memory using a dual phase TiO(x)N(y)/TiN charge trapping layer has been fabricated and its electrical properties were investigated. The TiO(x)N(y)/TiN layer was formed by partial oxidation of a pre-deposited TiN layer, and the formation of TiO(x)N(y)/SiO(x)N(y) was confirmed by high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analyses. The enlarged conduction (deltaphi(c) = 3.6 eV) and valence (deltaphi(v) = 2.5 eV) band offsets of the TiO(x)N(y)/TiN to SiO2 enabled low-voltage (+/- 6 V) and fast programming/erasing (P: 2.7 x 10(4) V/s and E: -5.1 x 10(4) V/s) operations, while the transition layer suppressed the trapped charge leakage, giving rise to good 10-year data retention with less than 35% V(th) decay.

  12. Comparative study of shale-gas production using single- and dual-continuum approaches

    KAUST Repository

    El-Amin, Mohamed

    2017-07-06

    In this paper, we explore the possibility of specifying the ideal hypothetical positions of matrices blocks and fractures in fractured porous media as a single-continuum reservoir model in a way that mimics the dual-porosity dual-permeability (DPDP) configuration. In order to get an ideal mimic, we use the typical configuration and geometrical hypotheses of the DPDP model for the SDFM. Unlike the DPDP model which consists of two equations for the two-continuum coupled by a transfer term, the proposed single-domain fracture model (SDFM) model consists of a single equation for the single-continuum. Each one of the two models includes slippage effect, adsorption, Knudsen diffusion, geomechanics, and thermodynamics deviation factor. For the thermodynamics calculations, the cubic Peng-Robinson equation of state is employed. The diffusion model is verified by calculating the total mass flux through a nanopore by combination of slip flow and Knudsen diffusion and compared with experimental data. A semi-implicit scheme is used for the time discretization while the thermodynamics equations are updated explicitly. The spatial discretization is done using the cell-centered finite difference (CCFD) method. Finally, numerical experiments are performed under variations of the physical parameters. Several results are discussed such as pressure, production rate and cumulative production. We compare the results of the two models using the same dimensions and physical and computational parameters. We found that the DPDP and the SDFM models production rate and cumulative production behave similarly with approximately the same slope but with some differences in values. Moreover, we found that the poroelasticity effect reduces the production rate and consequently the cumulative production rate but in the SDFM model the reservoir takes more time to achieve depletion than the DPDP model. The normal fracture factor which appears in the transfer term of the DPDP model is adjusted against

  13. Humble Opinion on the Learning Method of Voltage Comparator%电压比较器的学习方法

    Institute of Scientific and Technical Information of China (English)

    欧阳宏志

    2011-01-01

    The three keys method of voltage transferring characteristic is summarized in this paper.And then it is analyzed contrastively on three typical comparator.Three circuit examples are given about different comparators on fan temperature control,induction cooker overvoltage protection and BJT parameter separation.The teaching practice indicates that three stages method is helpful to the students' deepening their understanding of the arithmetic amplifier and the voltage comparator,so the foundation is established for the synthetic design of electronic system.%本文阐述了求解电压比较器传输特性的"三要素法",分析了三种典型的电压比较器电路,剖析了电压比较器在散热风扇自动控制、电磁炉过压保护和三极管参数分选电路中的应用实例。教学实践表明,采取由理论到实际的三个阶段学习法,有助于学生加深对于运算放大器和电压比较器的理解,提高分析和解决实际问题的能力。

  14. Prospectively ECG-triggered high-pitch coronary angiography with third-generation dual-source CT at 70 kVp tube voltage: feasibility, image quality, radiation dose, and effect of iterative reconstruction.

    Science.gov (United States)

    Hell, Michaela M; Bittner, Daniel; Schuhbaeck, Annika; Muschiol, Gerd; Brand, Michael; Lell, Michael; Uder, Michael; Achenbach, Stephan; Marwan, Mohamed

    2014-01-01

    Low tube voltage reduces radiation exposure in coronary CT angiography (CTA). Using 70 kVp tube potential has so far not been possible because CT systems were unable to provide sufficiently high tube current with low voltage. We evaluated feasibility, image quality (IQ), and radiation dose of coronary CTA using a third-generation dual-source CT system capable of producing 450 mAs tube current at 70 kVp tube voltage. Coronary CTA was performed in 26 consecutive patients with suspected coronary artery disease, selected for body weight Image noise was lower in IR vs FBP (60 ± 10 HU vs 74 ± 8 HU; P < .001). In patients <100 kg and with a regular heart rate <60 beats/min, third-generation dual-source CT using high-pitch spiral acquisition and 70 kVp tube voltage is feasible and provides both robust IQ and very low radiation exposure. Copyright © 2014 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

  15. Comparative Study of Fault Diagnostic Methods in Voltage Source Inverter Fed Three Phase Induction Motor Drive

    Science.gov (United States)

    Dhumale, R. B.; Lokhande, S. D.

    2017-05-01

    Three phase Pulse Width Modulation inverter plays vital role in industrial applications. The performance of inverter demeans as several types of faults take place in it. The widely used switching devices in power electronics are Insulated Gate Bipolar Transistors (IGBTs) and Metal Oxide Field Effect Transistors (MOSFET). The IGBTs faults are broadly classified as base or collector open circuit fault, misfiring fault and short circuit fault. To develop consistency and performance of inverter, knowledge of fault mode is extremely important. This paper presents the comparative study of IGBTs fault diagnosis. Experimental set up is implemented for data acquisition under various faulty and healthy conditions. Recent methods are executed using MATLAB-Simulink and compared using key parameters like average accuracy, fault detection time, implementation efforts, threshold dependency, and detection parameter, resistivity against noise and load dependency.

  16. Larger low voltage zone in endocardial unipolar map compared with that in epicardial bipolar map indicates difficulty in eliminating ventricular tachycardia by catheter ablation.

    Science.gov (United States)

    Miyamoto, Koji; Noda, Takashi; Satomi, Kazuhiro; Wada, Mitsuru; Nakajima, Ikutaro; Ishibashi, Kohei; Okamura, Hideo; Noguchi, Teruo; Anzai, Toshihisa; Yasuda, Satoshi; Ogawa, Hisao; Shimizu, Wataru; Aiba, Takeshi; Kamakura, Shiro; Kusano, Kengo

    2016-08-01

    these 6 patients. In the remaining 5 patients with a smaller LVZ in the ENDO UNI voltage map compared with the EPI BIP voltage map or no LVZ both at ENDO UNI and EPI BIP voltage map, VT was successfully eliminated in 4 of 5 patients. The LV ENDO UNI voltage map is useful in detecting EPI substrate in patients with cardiomyopathy. A larger LVZ in the ENDO UNI voltage map compared to that in the EPI BIP voltage map may indicate the presence of intramural substrate, which leads to difficulty in eliminating VT, even with combined ENDO- and EPI RFCA.

  17. Evaluation of global left ventricular function assessment by dual-source computed tomography compared with MRI

    Energy Technology Data Exchange (ETDEWEB)

    Vleuten, Pieter A. van der; Tio, Rene A.; Zijlstra, Felix [University Medical Centre Groningen, Thoraxcenter, Department of Cardiology, P.O. Box 30001, Groningen (Netherlands); Jonge, Gonda J. de; Lubbers, Daniel D.; Willems, Tineke P.; Oudkerk, Matthijs [University Medical Centre Groningen, Department of Radiology, Groningen (Netherlands)

    2009-02-15

    Left ventricular (LV) function assessment by dual-source computed tomography (DSCT) was compared with the reference standard method using magnetic resonance imaging (MRI). Accurate assessment of LV function is essential for the prediction of prognosis in cardiac disease. Thirty-four patients undergoing DSCT examination of the heart for various clinical indications underwent MRI after DSCT. Short-axis cine images were reconstructed from the DSCT datasets and were analyzed using a dedicated post-processing software-tool to generate global left ventricular function parameters. Five DSCT datasets were considered to be of insufficient image quality. DSCT showed a small overestimation of end-diastolic and end-systolic volumes of 11.0 ml and 3.5 ml, nrespectively. Myocardial mass assessed by DSCT showed an average underestimation of 0.2 g. DSCT showed a small overestimation of LV ejection fraction (LVEF) of 0.4%-point with a Bland-Altman interval of [-8.67 (0.40) 9.48]. Global LV functional parameters calculated from DSCT datasets acquired in daily clinical practice correlated well with MRI and may be considered interchangeable. However, visual assessment of the image quality of the short-axis cine slices should be performed to detect any artifacts in the DSCT data which could influence accuracy. (orig.)

  18. Design of voltage sag generator based on dual DSP and FPGA controller%基于双DSP和FPGA控制器的大功率电压暂降仪设计

    Institute of Scientific and Technical Information of China (English)

    张华赢; 李翔; 朱正国; 姚森敬; 史帅彬; 黄力鹏; 欧阳森; 曾江

    2015-01-01

    The voltage sag generator is designed based on dual digital signal processor (DSP) and field programmable logic gate array (FPGA) controller. Firstly, the main circuit of the voltage sag generator is designed. Then, the design of core unit (namely the controller) of the voltage sag generator is introduced in detail, the controller is composed of dual DSP and FPGA, and combine hardware system and software system to realize multi-function, intelligent control of voltage sag generator. Finally, the physical circuit of the voltage sag generator is set up according to the above theory, and the feasibility of the method is verified by the testing of HONKI3196.%设计了基于双数字信号处理器(DSP)和现场可编程逻辑门阵列(FPGA)架构控制器的电压暂降仪。首先,进行了电压暂降仪的主电路拓扑设计;然后对电压暂降仪的核心单元即控制器的设计进行了详细介绍,控制器采用双DSP和FPGA架构,硬件系统与软件系统相结合,实现对电压暂降仪多功能、智能化的控制;最后,按照理论设计,搭建了电压暂降仪实物电路,经过日置HONKI3196的测试,验证了本文设计的电压暂降仪的可行性。

  19. Low concentration contrast medium for dual-source computed tomography coronary angiography by a combination of iterative reconstruction and low-tube-voltage technique: Feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Minwen, E-mail: zhengmw2007@163.com; Liu, Ying, E-mail: yingyinglyly@126.com; Wei, Mengqi, E-mail: weimengqi2008@163.com; Wu, Yongjie, E-mail: wu18291988526@163.com; Zhao, Hongliang, E-mail: zhaohl1980@163.com; Li, Jian, E-mail: xjyylj@yeah.net

    2014-02-15

    Objectives: To assess the impact of low-concentration contrast medium on vascular enhancement, image quality and radiation dose of coronary CT angiography (cCTA) by using a combination of iterative reconstruction (IR) and low-tube-voltage technique. Materials and methods: One hundred patients were prospectively randomized to two types of contrast medium and underwent prospective electrocardiogram-triggering cCTA (Definition Flash, Siemens Healthcare; collimation: 128 mm × 0.6 mm; tube current: 300 mA s). Fifty patients received Iopromide 370 were scanned using the conventional tube setting (100 kVp or 120 kVp if BMI ≥ 25 kg/m{sup 2}) and reconstructed with filtered back projection (FBP). Fifty patients received Iodixanol 270 were scanned using the low-tube-voltage (80 kVp or 100 kVp if BMI ≥ 25 kg/m{sup 2}) technique and reconstructed with IR. CT attenuation was measured in coronary artery and other anatomical regions. Noise, image quality and radiation dose were compared. Results: Compared with two Iopromide 370 subgroups, Iomeprol 270 subgroups showed no significant difference in CT attenuation (576.63 ± 95.50 vs. 569.51 ± 118.93 for BMI < 25 kg/m{sup 2}, p = 0.647 and 394.19 ± 68.09 vs. 383.72 ± 63.11 for BMI ≥ 25 kg/m{sup 2}, p = 0.212), noise (in various anatomical regions of interest) and image quality (3.5 vs. 4.0, p = 0.13), but significantly (0.41 ± 0.17 vs. 0.94 ± 0.45 for BMI < 25 kg/m{sup 2}, p < 0.001 and 1.14 ± 0.24 vs. 2.37 ± 0.69 for BMI ≥ 25 kg/m{sup 2}, p < 0.001) lower radiation dose, which reflects dose saving of 56.4% and 51.9%, respectively. Conclusions: Combined IR with low-tube-voltage technique, a low-concentration contrast medium of 270 mg I/ml can still maintain the contrast enhancement without impairing image quality, as well as significantly lower the radiation dose.

  20. Interaction of ordinary Portland cement and Opalinus Clay: Dual porosity modelling compared to experimental data

    Science.gov (United States)

    Jenni, A.; Gimmi, T.; Alt-Epping, P.; Mäder, U.; Cloet, V.

    2017-06-01

    Interactions between concrete and clays are driven by the strong chemical gradients in pore water and involve mineral reactions in both materials. In the context of a radioactive waste repository, these reactions may influence safety-relevant clay properties such as swelling pressure, permeability or radionuclide retention. Interfaces between ordinary Portland cement and Opalinus Clay show weaker, but more extensive chemical disturbance compared to a contact between low-pH cement and Opalinus Clay. As a consequence of chemical reactions porosity changes occur at cement-clay interfaces. These changes are stronger and may lead to complete pore clogging in the case of low-pH cements. The prediction of pore clogging by reactive transport simulations is very sensitive to the magnitude of diffusive solute fluxes, cement clinker chemistry, and phase reaction kinetics. For instance, the consideration of anion-depleted porosity in clays substantially influences overall diffusion and pore clogging at interfaces. A new concept of dual porosity modelling approximating Donnan equilibrium is developed and applied to an ordinary Portland cement - Opalinus Clay interface. The model predictions are compared with data from the cement-clay interaction (CI) field experiment in the Mt Terri underground rock laboratory (Switzerland), which represent 5 y of interaction. The main observations such as the decalcification of the cement at the interface, the Mg enrichment in the clay detached from the interface, and the S enrichment in the cement detached from the interface, are qualitatively predicted by the new model approach. The model results reveal multiple coupled processes that create the observed features. The quantitative agreement of modelled and measured data can be improved if uncertainties of key input parameters (tortuosities, reaction kinetics, especially of clay minerals) can be reduced.

  1. SVPWM Strategy of Dual Inverters and Zero-Sequence Voltage Suppression Method%双逆变器SVPWM调制策略及零序电压抑制方法

    Institute of Scientific and Technical Information of China (English)

    安群涛; 姚飞; 孙立志; 孙力

    2016-01-01

    双逆变器具有与三电平逆变器相同的空间电压矢量分布,使直流母线电压利用率提高,在开放式绕组电机驱动系统中得到广泛应用.该文在分析双逆变器工作原理的基础上,研究双逆变器的调制策略,提出一种最大电压范围的双逆变器空间矢量脉宽调制(space vector pulse width modulation,SVPWM)策略,该策略首先将空间电压矢量平面划分为6个扇区,从而将参考电压矢量分解为两段:其中一段矢量等效为将双逆变器中的一个逆变器钳位在某一特定开关状态;另一段矢量由另外一个逆变器在其6个子扇区内调制实现.为抑制 SVPWM 调制所带来的零序电压,引入等效零矢量分配因子,通过零矢量产生的零序电压来抵消基本电压矢量合成时产生的零序电压.在开放式绕组永磁同步电机矢量控制系统中进行了仿真和实验研究,仿真和实验结果证明了所提方法的有效性.%The dual inverter has the same distribution of space voltage vectors with three-level inverters, and the utilization of DC link voltage is improved. Therefore, the dual inverter is widely applied in open-end winding motor drive systems. Based on the analysis of principle of the dual inverter, modulation strategies were researched and a dual inverter space vector pulse width modulation (SVPWM) strategy in maximum voltage range was proposed. In the proposed strategy, the plane can be divided into six sectors and then the voltage vector reference can be divided into two parts. One part is equivalent to a special switching state clamped by one inverter, and the other part is modulated by the other inverter in the six sub-sectors divided further in each sector. In order to suppress the zero-sequence voltage, a factor was introduced to redistribute zero voltage vectors during the synthesis. The zero-sequence voltage produced by basic voltage vectors can be counteracted by that of the redistributed zero voltage vectors

  2. Comparing Two Numerical Models in Simulating Hydrodynamics and Sediment Transport at a Dual Inlet System, West-Central Florida

    Science.gov (United States)

    2015-05-15

    1 COMPARING TWO NUMERICAL MODELS IN SIMULATING HYDRODYNAMICS AND SEDIMENT TRANSPORT AT A DUAL INLET SYSTEM, WEST-CENTRAL FLORIDA PING WANG1...numerical modeling systems, CMS and DELFT3D, in simulating the hydrodynamic and sediment transport processes. The model results are compared with...Introduction Simulating complex fields of wave, current, sediment transport , and morphology change in the vicinity of tidal inlets is a

  3. Postmenopausal women have an increased maximal platelet reactivity compared to men despite dual antiplatelet therapy.

    Science.gov (United States)

    Bobbert, Peter; Stellbaum, Caroline; Steffens, Daniel; Schütte, Claudia; Bobbert, Thomas; Schultheiss, Heinz Peter; Rauch, Ursula

    2012-12-01

    Dual antiplatelet medication with acetylsalicylic acid (ASA) and clopidogrel is the main therapy for patients with stable coronary vessel disease (CVD) after percutaneous coronary intervention (PCI). Despite platelet inhibition subgroups of patients have been shown to exhibit an increase of risk for adverse cardiovascular events. The aim of our study was to elucidate the influence of sex on platelet reactivity in patients with CVD under medication with ASA and clopidogrel. Two hundred and thirty patients with CVD on combined therapy with ASA (100 mg/day) and clopidogrel (75 mg/day) were included into our study. These patients were divided into a male (n = 128) and female (n = 102) group. Platelet reactivity was assessed by impedance aggregometry. Women demonstrated a significantly higher thrombin receptor-activating peptide (TRAP)-induced platelet reactivity than men (male 79.43 ± 28.55 U vs. female 89.3 ± 30.69 U; P 0.05) or arachidonic acid-induced (male 10.3 ± 12.87 U vs. female 12.76 ± 14.44 U; P > 0.05) platelet aggregation did not differ significantly between women and men. A multivariate linear regression model revealed female sex to be a significant prognostic marker for an increased TRAP-induced platelet reactivity, independent of the ASA and clopidogrel-associated platelet function inhibition. Sex differences did not influence the effectiveness of ASA or clopidogrel-mediated platelet function inhibition. Nevertheless, women had a significantly increased maximal platelet reactivity compared to men despite antiplatelet therapy.

  4. Radiation and contrast agent doses reductions by using 80-kV tube voltage in coronary computed tomographic angiography: A comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Jian-xin [Department of Radiology, Wuhan 161th Hospital, Wuhan (China); Wang, Yi-min, E-mail: wym6669@yahoo.com.cn [Department of Radiology, Wuhan 161th Hospital, Wuhan (China); Lu, Jin-guo [Department of Cardiology, Asia Heart Hospital, Wuhan (China); Zhang, Yu; Wang, Peng; Yang, Cheng [Department of Radiology, Wuhan 161th Hospital, Wuhan (China)

    2014-02-15

    Objective: To investigate the effects of 80-kilovoltage (kV) tube voltage coronary computed tomographic angiography (CCTA) with a reduced amount of contrast agent on qualitative and quantitative image quality parameters and on radiation dose in patients with a body mass index (BMI) <23.0 kg/m{sup 2}. Methods: One hundred and twenty consecutive patients with a BMI <23.0 kg/m{sup 2} and a low calcium load undergoing retrospective electrocardiogram (ECG)-gated dual-source CCTA were randomized into two groups [standard-tube voltage (120-kV) vs. low-tube voltage (80-kV)]. The injection flow rate of contrast agent (350 mg I/mL) was adjusted to body weight of each patient (4.5–5.5 mL/s in the 120-kV group and 2.8–3.8 mL/s in the 80-kV group). Radiation and contrast agent doses were evaluated. Quantitative image quality parameters and figure of merit (FOM) of coronary artery were evaluated. Each coronary segment was evaluated for image quality on a 4-point scale. Results: Compared with the 120-kV group, effective dose and amount of contrast agent in the 80-kV group were decreased by 57.8% and 30.5% (effective dose:2.7 ± 0.5vs. 6.4 ± 1.3 mSv; amount of contrast agent:57.1 ± 3.2 vs. 82.1 ± 6.1 mL; both p < 0.0001), respectively. Image noise was 22.7 ± 2.1 HU for 120-kV images and 33.2 ± 5.2 HU for 80-kV images (p < 0.0001). Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) in the proximal right coronary artery (RCA) and left main coronary artery (LMA) were all lower in 80-kV than 120-kV images (SNR in the proximal RCA: 16.5 ± 1.8 vs. 19.4 ± 2.8; SNR in the LMA: 16.3 ± 2.0 vs.19.6 ± 2.7; CNR in the proximal RCA: 19.4 ± 2.3 vs.22.9 ± 3.0; CNR in the LMA: 18.8 ± 2.4 vs. 22.7 ± 2.9; all p < 0.0001). FOM were all significantly higher in 80-kV than 120-kV images (proximal RCA: 146.7 ± 45.1 vs. 93.4 ± 32.0; LMA: 139.1 ± 47.2 vs. 91.6 ± 31.1; all p < 0.0001). There was no significant difference in image quality score between the two groups (3.3 ± 0

  5. Electrochemical Characteristics and Li+ Ion Intercalation Kinetics of Dual-phase Li4Ti5O12/Li2TiO3 Composite in Voltage Range of 0−3 V

    KAUST Repository

    Bhatti, Humaira S

    2016-04-20

    Li4Ti5O12, Li2TiO3 and dual-phase Li4Ti5O12/Li2TiO3 composite were prepared by sol-gel method with average particle size of 1 µm, 0.3 µm and 0.4 µm, respectively. Though Li2TiO3 is electrochemically inactive, the rate capability of Li4Ti5O12/Li2TiO3 is comparable to Li4Ti5O12 at different current rates. Li4Ti5O12/Li2TiO3 also shows good rate performance of 90 mA h g-1 at high rate of 10 C in voltage range of 1−3 V, attributable to increased interfaces in the composite. While Li4Ti5O12 delivers capacity retention of 88.6 % at 0.2 C over 50 cycles, Li4Ti5O12/Li2TiO3 exhibits no capacity fading at 0.2 C (40 cycles) and capacity retention of 98.45 % at 0.5 C (50 cycles). This highly stable cycling performance is attributed to the contribution of Li2TiO3 in preventing undesirable reaction of Li4Ti5O12 with the electrolyte during cycling. CV curves of Li4Ti5O12/Li2TiO3 in 0−3 V range exhibit two anodic peaks at 1.51 V and 0.7−0.0 V, indicating two modes of lithium intercalation into the lattice sites of active material. Owing to enhanced intercalation/de-intercalation kinetics in 0−3 V, composite electrode delivers superior rate performance of 203 mAh/g at 2.85 C and 140 mAh/g at 5.7 C with good reversible capacity retention over 100 cycles.

  6. Comparing hemp (Cannabis sativa L.) cultivars for dual-purpose production under contrasting environments

    NARCIS (Netherlands)

    Tang, Kailei; Struik, P.C.; Yin, X.; Thouminot, C.; Bjelková, M.; Stramkale, V.; Amaducci, S.

    2016-01-01

    Interest in hemp as a multi-purpose crop is growing worldwide and for the first time in 2015 it was cultivated in Europe on more than 20.000 ha as a dual-purpose crop, for the seeds and for the fibre. In the present study, fibre and seed productivity of 14 commercial cultivars were tested in four

  7. Grid to Standalone Transition Motion-Sensorless Dual-Inverter Control of PMSG With Asymmetrical Grid Voltage Sags and Harmonics Filtering

    DEFF Research Database (Denmark)

    Fatu, M.; Blaabjerg, Frede; Boldea, I.

    2014-01-01

    -coupling decoupling and line-voltage feedforward disturbance compensation. Also, a D-module filter is used to robustly extract the line voltage positive sequence followed by a phase-locked-loop (PLL) based observer to estimate the positive-sequence angle for control, including the case of asymmetric voltages......This paper describes a variable-speed motion-sensorless control system for permanent-magnet synchronous generator (PMSG) connected to grid via back-to-back inverters for wind energy generation. The grid-side inverter control system employs proportional-integral (PI) current controllers with cross...

  8. Bias voltage effects on tunneling magnetoresistance in Fe/MgAl2O4/Fe (001 ) junctions: Comparative study with Fe/MgO/Fe(001) junctions

    Science.gov (United States)

    Masuda, Keisuke; Miura, Yoshio

    2017-08-01

    We investigate bias voltage effects on the spin-dependent transport properties of Fe/MgAl 2O 4 /Fe(001) magnetic tunneling junctions (MTJs) by comparing them with those of Fe/MgO/Fe(001) MTJs. By means of the nonequilibrium Green's function method and the density functional theory, we calculate bias voltage dependencies of magnetoresistance (MR) ratios in both the MTJs. We find that in both the MTJs, the MR ratio decreases as the bias voltage increases and finally vanishes at a critical bias voltage Vc. We also find that the critical bias voltage Vc of the MgAl 2O 4 -based MTJ is clearly larger than that of the MgO-based MTJ. Since the in-plane lattice constant of the Fe/MgAl 2O 4 /Fe(001) supercell is twice that of the Fe/MgO/Fe(001) one, the Fe electrodes in the MgAl 2O 4 -based MTJs have an identical band structure to that obtained by folding the Fe band structure of the MgO-based MTJs in the Brillouin zone of the in-plane wave vector. We show that such a difference in the Fe band structure is the origin of the difference in the critical bias voltage Vc between the MgAl 2O 4 - and MgO-based MTJs.

  9. A comparative note on tunneling in AdS and in its boundary matrix dual

    Science.gov (United States)

    Chandrasekhar, B.; Mukherji, Sudipta; Sahay, Anurag; Sarkar, Swarnendu

    2012-05-01

    For charged black hole, within the grand canonical ensemble, the decay rate from thermal AdS to the black hole at a fixed high temperature increases with the chemical potential. We check that this feature is well captured by a phenomenological matrix model expected to describe its strongly coupled dual. This comparison is made by explicitly constructing the kink and bounce solutions around the de-confinement transition and evaluating the matrix model effective potential on the solutions.

  10. A Comparative Note on Tunneling in AdS and in its Boundary Matrix Dual

    CERN Document Server

    Chandrasekhar, B; Sahay, Anurag; Sarkar, Swarnendu

    2012-01-01

    For charged black hole, within the grand canonical ensemble, the decay rate from thermal AdS to the black hole at a fixed high temperature increases with the chemical potential. We check that this feature is well captured by a phenomenological matrix model expected to describe its strongly coupled dual. This comparison is made by explicitly constructing the kink and bounce solutions around the de-confinement transition and evaluating the matrix model effective potential on the solutions.

  11. Automatic voltage imbalance detector

    Science.gov (United States)

    Bobbett, Ronald E.; McCormick, J. Byron; Kerwin, William J.

    1984-01-01

    A device for indicating and preventing damage to voltage cells such as galvanic cells and fuel cells connected in series by detecting sequential voltages and comparing these voltages to adjacent voltage cells. The device is implemented by using operational amplifiers and switching circuitry is provided by transistors. The device can be utilized in battery powered electric vehicles to prevent galvanic cell damage and also in series connected fuel cells to prevent fuel cell damage.

  12. Coodinative Control of Active Power and DC-link Voltage for Cascaded Dual-Active-Bridge and Inverter in Bidirectional Applications

    DEFF Research Database (Denmark)

    Tian, Yanjun; Chen, Zhe; Deng, Fujin;

    2014-01-01

    A bidirectional interface converter is attractive for the flexible operation and control of a system consisting of a DC sub-grid and an AC sub-grid. Cascaded connection of a dual-active-bridge (DAB) with an inverter is an ideal topology for the bidirectional interface. However, due to the bidirec......A bidirectional interface converter is attractive for the flexible operation and control of a system consisting of a DC sub-grid and an AC sub-grid. Cascaded connection of a dual-active-bridge (DAB) with an inverter is an ideal topology for the bidirectional interface. However, due...

  13. A Comparative Study of the Characteristics of Cross-Linked, Oxidized and Dual-Modified Rice Starches

    Directory of Open Access Journals (Sweden)

    Feng-Xiang Yu

    2012-09-01

    Full Text Available Rice starch was cross-linked with epichlorohydrin (0.3%, w/w, on a dry starch basis and oxidized with sodium hypochlorite (2.5% w/w, respectively. Two dual-modified rice starch samples (oxidized cross-linked rice starch and cross-linked oxidized rice starch were obtained by the oxidation of cross-linked rice starch and the cross-linking of oxidized rice starch at the same level of reagents. The physicochemical properties of native rice starch, cross-linked rice starch and oxidized rice starch were also studied parallel with those of the two dual-modified rice starch samples using rapid visco analysis (RVA, differential scanning calorimetry (DSC, dynamic rheometry and scanning electron microscopy (SEM. It was found that the levels of cross-linking and oxidation used in this study did not cause any significant changes in the morphology of rice starch granules. Cross-linked oxidized starch showed lower swelling power (SP and solubility, and higher paste clarity in comparison with native starch. Cross-linked oxidized rice starch also had the lowest tendency of retrogradation and highest ability to resistant to shear compared with native, cross-linked, oxidized and oxidized cross-linked rice starches. These results suggest that the undesirable properties in native, cross-linked and oxidized rice starch samples could be overcome through dual-modification.

  14. Comparing capacity coefficient and dual task assessment of visual multitasking workload

    Energy Technology Data Exchange (ETDEWEB)

    Blaha, Leslie M.

    2017-07-14

    Capacity coefficient analysis could offer a theoretically grounded alternative approach to subjective measures and dual task assessment of cognitive workload. Workload capacity or workload efficiency is a human information processing modeling construct defined as the amount of information that can be processed by the visual cognitive system given a specified of amount of time. In this paper, I explore the relationship between capacity coefficient analysis of workload efficiency and dual task response time measures. To capture multitasking performance, I examine how the relatively simple assumptions underlying the capacity construct generalize beyond the single visual decision making tasks. The fundamental tools for measuring workload efficiency are the integrated hazard and reverse hazard functions of response times, which are defined by log transforms of the response time distribution. These functions are used in the capacity coefficient analysis to provide a functional assessment of the amount of work completed by the cognitive system over the entire range of response times. For the study of visual multitasking, capacity coefficient analysis enables a comparison of visual information throughput as the number of tasks increases from one to two to any number of simultaneous tasks. I illustrate the use of capacity coefficients for visual multitasking on sample data from dynamic multitasking in the modified Multi-attribute Task Battery.

  15. A Comparative Study of Analog Voltage-mode Control Methods for Ultra-Fast Tracking Power Supplies

    DEFF Research Database (Denmark)

    Høyerby, Mikkel Christian Wendelboe; Andersen, Michael Andreas E.

    2007-01-01

    (UFTPSs) for RF power amplifiers, where the switching converter needs to track a varying reference voltage precisely and quickly while maintaining low output impedance. The small-signal analyses performed on the different controllers show that the hysteretic-type controller can achieve the highest loop...

  16. Comparative Analysis of Different PWM Techniques to Reduce the Common Mode Voltage in Three-Level Neutral-Point-Clamped Inverters for Variable Speed Induction Drives

    Directory of Open Access Journals (Sweden)

    Bharati Raja

    2012-12-01

    Full Text Available This work presents the comparative study of the different PWM techniques to reduce the common-mode voltage (CMV at the output of neutral point diode clamped inverter for variable speed drives. Here the comparative study is done by the phase opposition disposed (POD, sinusoidal pulse width modulation (SPWM, phase disposition (PD, phase shift (PS space vector modulation (SVM techniques are proposed. A good trade-off between the quality of the output voltage and the partial magnitude of the CMV is achieved in this work. The scheme is proposed for three-level inverter. This work realizes the implementation of Three-level diode clamped MLI for three-phase (Y-Δ induction motor with the implementation of a space vector modulation technique without any additional control algorithm to reduce CMV within the range + Vdc/6. The Simulation with a 1HP induction motor drive system is setup in Matlab-2011b  and the same results validated effectively by hardware – FPGA-SPARTEN III processor and its shows that the CM voltage is effectively reduced and the maximum output voltage is not affected.  

  17. Comparing the magnetic resonant coupling radiofrequency stimulation to the traditional approaches: Ex-vivo tissue voltage measurement and electromagnetic simulation analysis

    Directory of Open Access Journals (Sweden)

    Sai Ho Yeung

    2015-09-01

    Full Text Available Recently, the design concept of magnetic resonant coupling has been adapted to electromagnetic therapy applications such as non-invasive radiofrequency (RF stimulation. This technique can significantly increase the electric field radiated from the magnetic coil at the stimulation target, and hence enhancing the current flowing through the nerve, thus enabling stimulation. In this paper, the developed magnetic resonant coupling (MRC stimulation, magnetic stimulation (MS and transcutaneous electrical nerve stimulation (TENS are compared. The differences between the MRC RF stimulation and other techniques are presented in terms of the operating mechanism, ex-vivo tissue voltage measurement and electromagnetic simulation analysis. The ev-vivo tissue voltage measurement experiment is performed on the compared devices based on measuring the voltage induced by electromagnetic induction at the tissue. The focusing effect, E field and voltage induced across the tissue, and the attenuation due to the increase of separation between the coil and the target are analyzed. The electromagnetic stimulation will also be performed to obtain the electric field and magnetic field distribution around the biological medium. The electric field intensity is proportional to the induced current and the magnetic field is corresponding to the electromagnetic induction across the biological medium. The comparison between the MRC RF stimulator and the MS and TENS devices revealed that the MRC RF stimulator has several advantages over the others for the applications of inducing current in the biological medium for stimulation purposes.

  18. Comparative Genome Analyses of Streptococcus suis Isolates from Endocarditis Demonstrate Persistence of Dual Phenotypic Clones.

    Directory of Open Access Journals (Sweden)

    Mari Tohya

    Full Text Available Many bacterial species coexist in the same niche as heterogeneous clones with different phenotypes; however, understanding of infectious diseases by polyphenotypic bacteria is still limited. In the present study, encapsulation in isolates of the porcine pathogen Streptococcus suis from persistent endocarditis lesions was examined. Coexistence of both encapsulated and unencapsulated S. suis isolates was found in 26 out of 59 endocarditis samples. The isolates were serotype 2, and belonged to two different sequence types (STs, ST1 and ST28. The genomes of each of the 26 pairs of encapsulated and unencapsulated isolates from the 26 samples were sequenced. The data showed that each pair of isolates had one or more unique nonsynonymous mutations in the cps gene, and the encapsulated and unencapsulated isolates from the same samples were closest to each other. Pairwise comparisons of the sequences of cps genes in 7 pairs of encapsulated and unencapsulated isolates identified insertion/deletions (indels ranging from one to 104 bp in different cps genes of unencapsulated isolates. Capsule expression was restored in a subset of unencapsulated isolates by complementation in trans with cps expression vectors. Examination of gene content common to isolates indicated that mutation frequency was higher in ST28 pairs than in ST1 pairs. Genes within mobile genetic elements were mutation hot spots among ST28 isolates. Taken all together, our results demonstrate the coexistence of dual phenotype (encapsulated and unencapsulated bacterial clones and suggest that the dual phenotypes arose independently in each farm by means of spontaneous mutations in cps genes.

  19. A Comparative Study of Analog Voltage-mode Control Methods for Ultra-Fast Tracking Power Supplies

    DEFF Research Database (Denmark)

    Høyerby, Mikkel Christian Wendelboe; Andersen, Michael Andreas E.

    2007-01-01

    This paper presents a theoretical and experimental comparison of the standard PWM/PID voltage-mode control method for single-phase buck converters with two highperformance self-oscillating (a.k.a. sliding mode) control methods. The application considered is ultra-fast tracking power supplies...... (UFTPSs) for RF power amplifiers, where the switching converter needs to track a varying reference voltage precisely and quickly while maintaining low output impedance. The small-signal analyses performed on the different controllers show that the hysteretic-type controller can achieve the highest loop......-oscillating control is shown to reduce the worst-case UFTPS output impedance by a factor of 10....

  20. Comparable cerebral oxygenation patterns in younger and older adults during dual-task walking with increasing load

    Directory of Open Access Journals (Sweden)

    Sarah A. Fraser

    2016-10-01

    Full Text Available The neuroimaging literature on dual-task gait clearly demonstrates increased prefrontal cortex (PFC involvement when performing a cognitive task while walking. However, findings from direct comparisons of the cerebral oxygenation patterns of younger (YA and older (OA adults during dual-task walking are mixed and it is unclear how YA and OA respond to increasing cognitive load (difficulty while walking. This functional near infra-red (fNIRS study examined cerebral oxygenation of YA and OA during self-paced dual-task treadmill walking at two different levels of cognitive load (auditory n-back. Changes in accuracy (% as well as oxygenated (HbO and deoxygenated (HbR hemoglobin were examined. For the HbO and HbR measures, eight regions of interest (ROIs were assessed: the anterior and posterior dorsolateral and ventrolateral PFC (aDLPFC, pDLPFC, aVLPFC, pVLPFC in each hemisphere. Nineteen YA (M = 21.83 yrs and 14 OA (M = 66.85 yrs walked at a self-selected pace while performing auditory 1-back and 2-back tasks. Walking alone (single motor: SM and performing the cognitive tasks alone (single cognitive: SC were compared to dual-task walking (DT = SM + SC. In the behavioural data, participants were more accurate in the lowest level of load (1-back compared to the highest (2-back; p ˂ .001. YA were more accurate than OA overall (p = .009, and particularly in the 2-back task (p = .048. In the fNIRS data, both younger and older adults had task effects (SM < DT in specific ROIs for ∆HbO (3 YA, 1 OA and ∆HbR (7 YA, 8 OA. After controlling for walk speed differences, direct comparisons between YA and OA did not reveal significant age differences, but did reveal a difficulty effect in HbO in the left aDLPFC (p = .028 and significant task effects (SM < DT in HbR for 6 of the 8 ROIs. Findings suggest that YA and OA respond similarly to manipulations of cognitive load when walking on a treadmill at a self-selected pace.

  1. Comparative effectiveness of single and dual rapid diagnostic tests for syphilis and HIV in antenatal care services in Colombia.

    Science.gov (United States)

    Gaitán-Duarte, Hernando Guillermo; Newman, Lori; Laverty, Maura; Habib, Ndema Abu; González-Gordon, Lina María; Ángel-Müller, Edith; Abella, Catleya; Barros, Esther Cristina; Rincón, Carlos; Caicedo, Sidia; Gómez, Bertha; Pérez, Freddy

    2016-12-01

    To assess the effectiveness of a dual rapid test compared to a single rapid test for syphilis and HIV screening. A cluster-randomized open-label clinical trial was performed in 12 public antenatal care (ANC) centers in the cities of Bogotá and Cali, Colombia. Pregnant women who were over 14 years of age at their first antenatal visit and who had not been previously tested for HIV and syphilis during the current pregnancy were included. Pregnant women were randomized to single HIV and single syphilis rapid diagnostic tests (Arm A) or to dual HIV and syphilis rapid diagnostic tests (Arm B). The four main outcomes measured were: (1) acceptability of the test, (2) uptake in testing, (3) treatment on the same day (that is, timely treatment), and (4) treatment at any time for positive rapid test cases. Bivariate and multivariate analyses were calculated to adjust for the clustering effect and the period. A total of 1 048 patients were analyzed in Arm A, and 1 166 in Arm B. Acceptability of the rapid tests was 99.8% in Arm A and 99.6% in Arm B. The prevalence of positive rapid tests was 2.21% for syphilis and 0.36% for HIV. Timely treatment was provided to 20 of 29 patients (69%) in Arm A and 16 of 20 patients (80%) in Arm B (relative risk (RR), 1.10; 95% confidence interval (CI): (1.00 -1.20). Treatment at any time was given to 24 of 29 patients (83%) in Arm A and to 20 of 20 (100%) in Arm B (RR, 1.11; 95% CI: 1.01-1.22). There were no differences in patient acceptability, testing and timely treatment between dual rapid tests and single rapid tests for HIV and syphilis screening in the ANC centers. Same-day treatment depends also on the interpretation of and confidence in the results by the health providers.

  2. Dual Adaptive Filtering by Optimal Projection Applied to Filter Muscle Artifacts on EEG and Comparative Study

    Directory of Open Access Journals (Sweden)

    Samuel Boudet

    2014-01-01

    Full Text Available Muscle artifacts constitute one of the major problems in electroencephalogram (EEG examinations, particularly for the diagnosis of epilepsy, where pathological rhythms occur within the same frequency bands as those of artifacts. This paper proposes to use the method dual adaptive filtering by optimal projection (DAFOP to automatically remove artifacts while preserving true cerebral signals. DAFOP is a two-step method. The first step consists in applying the common spatial pattern (CSP method to two frequency windows to identify the slowest components which will be considered as cerebral sources. The two frequency windows are defined by optimizing convolutional filters. The second step consists in using a regression method to reconstruct the signal independently within various frequency windows. This method was evaluated by two neurologists on a selection of 114 pages with muscle artifacts, from 20 clinical recordings of awake and sleeping adults, subject to pathological signals and epileptic seizures. A blind comparison was then conducted with the canonical correlation analysis (CCA method and conventional low-pass filtering at 30 Hz. The filtering rate was 84.3% for muscle artifacts with a 6.4% reduction of cerebral signals even for the fastest waves. DAFOP was found to be significantly more efficient than CCA and 30 Hz filters. The DAFOP method is fast and automatic and can be easily used in clinical EEG recordings.

  3. Comparative study of SVPWM (space vector pulse width modulation) & SPWM (sinusoidal pulse width modulation) based three phase voltage source inverters for variable speed drive

    Science.gov (United States)

    Ahmed, Waheed; Usman Ali, Syed M.

    2013-12-01

    We have performed comparative studies of Space Vector Pulse Width Modulation (SVPWM) and Sinusoidal Pulse Width Modulation (SPWM) techniques utilizing MATLAB tools. During these investigations, we carried out intensive simulations, comprehensively analyzed the obtained results and compared the harmonic density, power factor (PF), & switching losses of SVPWM and SPWM. It has been observed during investigations that if the switching frequency is high then losses due to harmonics are negligible, thus based on obtained results we suggested that the SVPWM technique is a more reliable solution. Because SVPWM utilizes DC bus voltage more efficiently, generates less Total Harmonic Distortion (THD) and has higher output quality it provides flexible control of output voltage and output frequency for Variable Speed Drive (VSD).

  4. Device for monitoring cell voltage

    Science.gov (United States)

    Doepke, Matthias [Garbsen, DE; Eisermann, Henning [Edermissen, DE

    2012-08-21

    A device for monitoring a rechargeable battery having a number of electrically connected cells includes at least one current interruption switch for interrupting current flowing through at least one associated cell and a plurality of monitoring units for detecting cell voltage. Each monitoring unit is associated with a single cell and includes a reference voltage unit for producing a defined reference threshold voltage and a voltage comparison unit for comparing the reference threshold voltage with a partial cell voltage of the associated cell. The reference voltage unit is electrically supplied from the cell voltage of the associated cell. The voltage comparison unit is coupled to the at least one current interruption switch for interrupting the current of at least the current flowing through the associated cell, with a defined minimum difference between the reference threshold voltage and the partial cell voltage.

  5. Comparative study of the gating motif and C-type inactivation in prokaryotic voltage-gated sodium channels.

    Science.gov (United States)

    Irie, Katsumasa; Kitagawa, Kazuya; Nagura, Hitoshi; Imai, Tomoya; Shimomura, Takushi; Fujiyoshi, Yoshinori

    2010-02-05

    Prokaryotic voltage-gated sodium channels (Na(V)s) are homotetramers and are thought to inactivate through a single mechanism, named C-type inactivation. Here we report the voltage dependence and inactivation rate of the NaChBac channel from Bacillus halodurans, the first identified prokaryotic Na(V), as well as of three new homologues cloned from Bacillus licheniformis (Na(V)BacL), Shewanella putrefaciens (Na(V)SheP), and Roseobacter denitrificans (Na(V)RosD). We found that, although activated by a lower membrane potential, Na(V)BacL inactivates as slowly as NaChBac. Na(V)SheP and Na(V)RosD inactivate faster than NaChBac. Mutational analysis of helix S6 showed that residues corresponding to the "glycine hinge" and "PXP motif" in voltage-gated potassium channels are not obligatory for channel gating in these prokaryotic Na(V)s, but mutations in the regions changed the inactivation rates. Mutation of the region corresponding to the glycine hinge in Na(V)BacL (A214G), Na(V)SheP (A216G), and NaChBac (G219A) accelerated inactivation in these channels, whereas mutation of glycine to alanine in the lower part of helix S6 in NaChBac (G229A), Na(V)BacL (G224A), and Na(V)RosD (G217A) reduced the inactivation rate. These results imply that activation gating in prokaryotic Na(V)s does not require gating motifs and that the residues of helix S6 affect C-type inactivation rates in these channels.

  6. Design Analysis of a Novel Low Triggering Voltage Dual Direction SCR ESD Device in 0. 18μm Mixed Mode RFCMOS Technology%0.18μm混合信号RFCMOS工艺中新型低触发电压双向SCR静电防护器件的设计

    Institute of Scientific and Technical Information of China (English)

    朱科翰; 于宗光; 董树荣; 韩雁

    2008-01-01

    A novel SCR on-chip ESD device is proposed to protect IC chips against ESD stressing in two opposite directions. The triggering voltages of four types of dual direction SCRs (DDSCR) are compared and analyzed, pMOS or nMOS are embedded into the structures to adjust their triggering voltages. Both MOSFETs embedded DDSCRs have tunable triggering voltage,low DC leakage (~pA), and fast turn on speed snapback Ⅰ-Ⅴ characteristics without latch-up problem. It achieves high ESD performance of ~94V/μm. The new ESD protection devices are area efficient and can reduce the para sitic effects significantly.%提出了一类新型片上SCR静电放电防护器件,此类器件用于保护芯片双向抗击静电应力.比较和分析了四种双向SCR器件的触发电压.其中采用嵌入pMOS管或nMOS管的双向SCR器件结构具有可调触发电压,低漏电流(~pA)和开启速度快的骤回Ⅰ-Ⅴ特性,并且没有闭锁问题.该器件的抗ESD能力可达~94V/μm.此类新型ESD防护器件具有面积小、寄生效应小的特点.

  7. A comparative study of diesel ignited methane and propane dual fuel low temperature combustion in a single cylinder research engine

    Science.gov (United States)

    Raihan, Mostafa Shameem

    The objective of this thesis is to investigate and compare the performance and emissions characteristics of diesel-ignited methane and diesel-ignited propane dual fuel LTC in a single cylinder research engine (SCRE) at a constant engine load of 5.1 bar net indicated mean effective pressure (IMEP) and at a constant engine speed of 1500 RPM. Percentage of energy substitution of propane or methane (0 - 90 percent), diesel injection timing (SOI: 355 CAD -- 280 CAD), rail pressure (200 bar -- 1300 bar) and boost pressure (1.1 bar -- 1.8 bar) were varied to quantify their impact on engine performance and engine-out ISNOx, ISHC, ISCO, and smoke emissions. Advancing SOI to 310 CAD and beyond yielded simultaneous ISNOx and smoke emissions. A rail pressure of 500 bar was the optimal one for both fueling combinations while increasing boost pressure over 1.2 bar had a very little effect on ISNOx and smoke emissions.

  8. A comparative study on dual colour soft aperture cascaded second-order mode-locking with different nonlinear optical crystals

    Indian Academy of Sciences (India)

    Shyamal Mondal; Satya Pratap Singh; Sourabh Mukhopadhyay; Aditya Date; Kamal Hussain; Shouvik Mukherjee; Prasanta Kumar Datta

    2014-02-01

    A comparative study in terms of optimized output power and stability is made on cascaded second-order nonlinear optical mode-locking with KTP, BBO and LBO crystals for both 1064 nm and 532 nm. Large nonlinear optical phase shift achieved in a non-phase-matched second harmonic generating crystal, is transformed into amplitude modulation through soft aperturing the nonlinear cavity mode variation at the laser gain medium to mode-lock a Nd:YVO4 laser. The laser delivers stable dual wavelength cw mode-locked pulse train with pulse duration 10.3 ps and average power of 1.84 W and 255 mW at 1064 nm and 532 nm respectively for the optimum performance in type-II KTP crystal. The exceptional stability achieved with KTP is accounted by simulating the mode-size variation with phase mismatch.

  9. Dual Input High Step-up DC-DC Converters With Voltage Multiplier Cells%一种基于倍压单元的双输入高增益直流变换器

    Institute of Scientific and Technical Information of China (English)

    孙鹏菊; 李正宇; 张冀; 周雒维

    2016-01-01

    According to the problems that more than one energy source, low output voltage of the battery module and unstable output power in the distributed photovoltaic power generation system, a dual input high step-up DC-DC converter with capacitor-diode multiplier cells was proposed in this paper. The proposed topology has the following advantages: the voltage gain is high, the voltage stress of the switches is low, there are more control freedoms and the sources can deliver power to the load with flexible power management methods. Firstly, the operation mode and the performance characteristics of the converter were presented in detail. Secondly, the steady state analysis, the voltage and current stresses of the switches and the relationship between the input currents were also introduced. Finally, the correctness and feasibility of the proposed circuit topology and the theoretical analysis were fully verified by a 1000W prototype.%针对分布式光伏发电系统电池模块多、输出电压低、功率不稳定等问题,提出了一种基于电容-二极管倍压单元的双输入高增益Boost型直流变换器。该变换器具有电压调节增益高、开关器件电压应力小、控制自由度多、各输入源功率可灵活分配等优点。首先分析了双输入高增益 Boost变换器的工作原理及性能特点,给出了变换器的稳态关系式及开关管电压电流应力计算结果,最后通过一台1000W的实验样机,验证了电路拓扑和理论分析的可行性和正确性。

  10. A Comparative Study of Motivational Orientation of Elementary School English Learners in a Dual Language Immersion Program and a Transitional Bilingual Education Program

    Science.gov (United States)

    Ma, Elizabeth C.

    2010-01-01

    The focus of this research is to compare the motivational orientation of English Learners in a Dual Language Immersion and a Transitional Bilingual Education program. These programs were chosen for several reasons. First, comparative studies on the various variables and constructs relating to English Learners in these two instructional models are…

  11. Comparative impact of voltage-gated calcium channels and NMDA receptors on mitochondria-mediated neuronal injury.

    Science.gov (United States)

    Stanika, Ruslan I; Villanueva, Idalis; Kazanina, Galina; Andrews, S Brian; Pivovarova, Natalia B

    2012-05-09

    Glutamate excitotoxicity, a major component of many neurodegenerative disorders, is characterized by excessive calcium influx selectively through NMDARs. However, there is a substantial uncertainty concerning why other known routes of significant calcium entry, in particular, VGCCs, are not similarly toxic. Here, we report that in the majority of neurons in rat hippocampal and cortical cultures, maximal L-type VGCC activation induces much lower calcium loading than toxic NMDAR activation. Consequently, few depolarization-activated neurons exhibit calcium deregulation and cell death. Activation of alternative routes of calcium entry induced neuronal death in proportion to the degree of calcium loading. In a small subset of neurons, depolarization evoked stronger calcium elevations, approaching those induced by toxic NMDA. These neurons were characterized by elevated expression of VGCCs and enhanced voltage-gated calcium currents, mitochondrial dysfunction and cell death. Preventing VGCC-dependent mitochondrial calcium loading resulted in stronger cytoplasmic calcium elevations, whereas inhibiting mitochondrial calcium clearance accelerated mitochondrial depolarization. Both observations further implicate mitochondrial dysfunction in VGCC-mediated cell death. Results indicate that neuronal vulnerability tracks the extent of calcium loading but does not appear to depend explicitly on the route of calcium entry.

  12. The Planning of Urban Medium Voltage Distribution Network Based on Dual-coding Immune Genetic Algorithm%基于双重编码免疫遗传算法城市中压配电网规划

    Institute of Scientific and Technical Information of China (English)

    崔凤仙; 刘阳

    2011-01-01

    针对配电网络规划中出现的中压配电站容量和位置不确定的情况,提出将中压配电站容量和位置连同网架结构、导线型号、线路回数等一起作为变量,采用整数编码与矩阵实数编码相结合的双重编码方式进行中压配电网络规划,其中整数编码用以确定网架结构、导线型号以及线路回数,而矩阵实数编码用以调整虚拟负荷点所带负荷量。设计了用于该规划的各项免疫遗传算法操作,并通过算例验证了该算法的有效性。%Considering the uncertainty of the capacities and the locations of the medium-voltage distribution stations in contribution network planning,this paper proposes a method for the planning,which employs a dual encoding way that takes the capacities and positions of the distribution stations,together with the structure of network,the types of the transmission lines and the number of circuit lines as parameters,and combines the integer encoding and real-matrix encoding.Here the integer encoding is for the structure of network,the types of the transmission lines and the number of circuit lines while the real-matrix encoding is for optimizing loads on the virtual load points.The operators of immune genetic algorithm for medium-voltage network planning are designed and applied to a real power distribution system,and it proves that the algorithm is effective.

  13. Dual-task motor performance with a tongue-operated assistive technology compared with hand operations

    Directory of Open Access Journals (Sweden)

    Johnson Ashley N

    2012-01-01

    Full Text Available Abstract Background To provide an alternative motor modality for control, navigation, and communication in individuals suffering from impairment or disability in hand functions, a Tongue Drive System (TDS has been developed that allows for real time tracking of tongue motion in an unobtrusive, wireless, and wearable device that utilizes the magnetic field generated by a miniature disk shaped magnetic tracer attached to the tip of the tongue. The purpose of the study was to compare the influence of a concurrent motor or cognitive task on various aspects of simple movement control between hand and tongue using the TDS technology. Methods Thirteen young able-bodied adults performed rapid and slow goal-directed movements of hand and tongue (with TDS with and without a concurrent motor (hand or tongue or cognitive (arithmetic and memory task. Changes in reaction time, completion time, speed, correctness, accuracy, variability of displacement, and variability of time due to the addition of a concurrent task were compared between hand and tongue. Results The influence of an additional concurrent task on motor performance was similar between the hand and tongue for slow movement in controlling their displacement. In rapid movement with a concurrent motor task, most aspects of motor performance were degraded in hand, while tongue speed during rapid continuous task was maintained. With a concurrent cognitive task, most aspects of motor performance were degraded in tongue, while hand accuracy during the rapid discrete task and hand speed during the rapid continuous task were maintained. Conclusion Rapid goal-directed hand and tongue movements were more consistently susceptible to interference from concurrent motor and cognitive tasks, respectively, compared with the other movement.

  14. A dual comparative approach: integrating lines of evidence from human evolutionary neuroanatomy and neurodevelopmental disorders.

    Science.gov (United States)

    Hanson, Kari L; Hrvoj-Mihic, Branka; Semendeferi, Katerina

    2014-01-01

    The evolution of the human brain has been marked by a nearly 3-fold increase in size since our divergence from the last common ancestor shared with chimpanzees and bonobos. Despite increased interest in comparative neuroanatomy and phylogenetic methods, relatively little is known regarding the effects that this enlargement has had on its internal organization, and how certain areas of the brain have differentially expanded over evolutionary time. Analyses of the microstructure of several regions of the human cortex and subcortical structures have demonstrated subtle changes at the cellular and molecular level, suggesting that the human brain is more than simply a 'scaled-up' primate brain. Ongoing research in comparative neuroanatomy has much to offer regarding our understanding of human brain evolution. Through analysis of the neuroanatomical phenotype at the level of reorganization in cytoarchitecture and cellular morphology, new data continue to highlight changes in cell density and organization associated with volumetric changes in discrete regions. An understanding of the functional significance of variation in neural circuitry can further be approached through studies of atypical human development. Many neurodevelopmental disorders cause disruption in systems associated with uniquely human features of cognition, including language and social cognition. Understanding the genetic and developmental mechanisms that underlie variation in the human cognitive phenotype can help to clarify the functional significance of interspecific variation. By uniting approaches from comparative neuroanatomy and neuropathology, insights can be gained that clarify trends in human evolution. Here, we explore these lines of evidence and their significance for understanding functional variation between species as well as within neuropathological variation in the human brain.

  15. Comparative Performance Analysis of XOR-XNOR Function Based High-Speed CMOS Full Adder Circuits For Low Voltage VLSI Design

    Directory of Open Access Journals (Sweden)

    Sudarshan Tiwari

    2012-05-01

    Full Text Available This paper presents comparative study of high-speed, low-power and low voltage full adder circuits. Our approach is based on XOR-XNOR design full adder circuits in a single unit. A low power and high performance 9T full adder cell using a design style called “XOR (3T” is discussed. The designed circuit commands a high degree of regularity and symmetric higher density than the conventional CMOS design style as well as it lowers power consumption by using XOR (3T logic circuits. Gate Diffusion Input (GDI technique of low-power digital combinatorial circuit design is also described. This technique helps inreducing the power consumption and the area of digital circuits while maintaining low complexity of logic design. This paper analyses, evaluates and compares the performance of various adder circuits. Severalsimulations conducted using different voltage supplies, load capacitors and temperature variation demonstrate the superiority of the XOR (3T based full adder designs in term of delay, power and powerdelay product (PDP compared to the other full adder circuits. Simulation results illustrate the superiority of the designed adder circuits against the conventional CMOS, TG and Hybrid full adder circuits in terms of power, delay and power delay product (PDP.

  16. Comparative Analysis of Dual Control and RLS Identification Control for System with Dual Uncertainties%双重不确定系统对偶控制与RLS辨识控制比较分析

    Institute of Scientific and Technical Information of China (English)

    杨恒占; 高韵; 钱富才

    2016-01-01

    In order to identify unknown parameters and to track system target output value in dual uncertainty system,dual control and recursive least squares (RLS)identification control are presented for the stochastic system.The control strategy of double dual control and the recursive least squares identification controland is put forward.Through dual uncertain stochastic system simulation,the dual control and least squares identification performance of the control strategy are comparatively analyzed. The results show:The dual control strategy is used for dual uncertainty parameter identification of stochastic system,its realtime performance and stability are better than the least squares identification control;When the unknown parameters of stochastic system change in the running process,dual control strategy can still be effective track system for the target output value,and the tracking error is consistent with the value before switching;RLS identification control cannot effectively track system output value, and fails to track.%为了辨识双重不确定性系统未知参数,跟踪系统目标输出值,本文对未知参数随机系统分别进行了对偶控制和最小二乘(RLS)辨识控制.提出了双重不确定随机系统对偶控制和最小二乘辨识控制策略.通过双重不确定随机系统仿真,比较分析了对偶控制和最小二乘辨识控制策略的性能.结果表明:该对偶控制策略用于双重不确定性随机系统参数辨识时实时性和稳定性优于最小二乘辨识控制;随机系统在运行过程中未知参数变化时,对偶控制策略仍可有效跟踪系统目标输出值,且对偶控制跟踪误差和切换之前保持一致,而RLS辨识控制不能有效跟踪系统目标输出值,跟踪失效.

  17. A Prospective Comparative Study of Parathyroid Dual-Phase Scintigraphy, Dual-Isotope Subtraction Scintigraphy, 4D-CT, and Ultrasonography in Primary Hyperparathyroidism

    DEFF Research Database (Denmark)

    Krakauer, Martin; Wieslander, Bente; Myschetzky, Peter Sand

    2016-01-01

    PURPOSE: Preoperative localization of the diseased parathyroid gland(s) in primary hyperparathyroidism allows for minimally invasive surgery. This study was designed to establish the optimal first-line preoperative imaging modality. PATIENTS AND METHODS: Ninety-one patients were studied...... standard. RESULTS: Ninety-seven hyperfunctioning parathyroid glands (HPGs) were identified by the reference standard. Sensitivity and specificity for subtraction PS, dual-phase PS, 4D-CT, and US were 93%, 65%, 58%, and 57% as well as 99%, 99.6%, 86%, and 95%, respectively. Interrater agreement...

  18. A Comparative Study of Electric Load Curve Changes in an Urban Low-Voltage Substation in Spain during the Economic Crisis (2008–2013)

    Science.gov (United States)

    Lara-Santillán, Pedro M.; Mendoza-Villena, Montserrat; Fernández-Jiménez, L. Alfredo; Mañana-Canteli, Mario

    2014-01-01

    This paper presents a comparative study of the electricity consumption (EC) in an urban low-voltage substation before and during the economic crisis (2008–2013). This low-voltage substation supplies electric power to near 400 users. The EC was measured for an 11-year period (2002–2012) with a sampling time of 1 minute. The study described in the paper consists of detecting the changes produced in the load curves of this substation along the time due to changes in the behaviour of consumers. The EC was compared using representative curves per time period (precrisis and crisis). These representative curves were obtained after a computational process, which was based on a search for days with similar curves to the curve of a determined (base) date. This similitude was assessed by the proximity on the calendar, day of the week, daylight time, and outdoor temperature. The last selection parameter was the error between the nearest neighbour curves and the base date curve. The obtained representative curves were linearized to determine changes in their structure (maximum and minimum consumption values, duration of the daily time slot, etc.). The results primarily indicate an increase in the EC in the night slot during the summer months in the crisis period. PMID:24895677

  19. A comparative study of electric load curve changes in an urban low-voltage substation in Spain during the economic crisis (2008-2013).

    Science.gov (United States)

    Lara-Santillán, Pedro M; Mendoza-Villena, Montserrat; Fernández-Jiménez, L Alfredo; Mañana-Canteli, Mario

    2014-01-01

    This paper presents a comparative study of the electricity consumption (EC) in an urban low-voltage substation before and during the economic crisis (2008-2013). This low-voltage substation supplies electric power to near 400 users. The EC was measured for an 11-year period (2002-2012) with a sampling time of 1 minute. The study described in the paper consists of detecting the changes produced in the load curves of this substation along the time due to changes in the behaviour of consumers. The EC was compared using representative curves per time period (precrisis and crisis). These representative curves were obtained after a computational process, which was based on a search for days with similar curves to the curve of a determined (base) date. This similitude was assessed by the proximity on the calendar, day of the week, daylight time, and outdoor temperature. The last selection parameter was the error between the nearest neighbour curves and the base date curve. The obtained representative curves were linearized to determine changes in their structure (maximum and minimum consumption values, duration of the daily time slot, etc.). The results primarily indicate an increase in the EC in the night slot during the summer months in the crisis period.

  20. A Comparative Study of Electric Load Curve Changes in an Urban Low-Voltage Substation in Spain during the Economic Crisis (2008–2013

    Directory of Open Access Journals (Sweden)

    Pedro M. Lara-Santillán

    2014-01-01

    Full Text Available This paper presents a comparative study of the electricity consumption (EC in an urban low-voltage substation before and during the economic crisis (2008–2013. This low-voltage substation supplies electric power to near 400 users. The EC was measured for an 11-year period (2002–2012 with a sampling time of 1 minute. The study described in the paper consists of detecting the changes produced in the load curves of this substation along the time due to changes in the behaviour of consumers. The EC was compared using representative curves per time period (precrisis and crisis. These representative curves were obtained after a computational process, which was based on a search for days with similar curves to the curve of a determined (base date. This similitude was assessed by the proximity on the calendar, day of the week, daylight time, and outdoor temperature. The last selection parameter was the error between the nearest neighbour curves and the base date curve. The obtained representative curves were linearized to determine changes in their structure (maximum and minimum consumption values, duration of the daily time slot, etc.. The results primarily indicate an increase in the EC in the night slot during the summer months in the crisis period.

  1. A Comparative Evaluation of Accuracy of the Dies Affected by Tray Type, Material Viscosity, and Pouring Sequence of Dual and Single Arch Impressions- An In vitro Study.

    Science.gov (United States)

    Kulkarni, Poonam R; Kulkarni, Rahul S; Shah, Rupal J; Chhajlani, Rahul; Saklecha, Bhuwan; Maru, Kavita

    2017-04-01

    The clinician's skill, impression techniques, and materials play a very important role in recording fine details in an impression for accuracy of fixed partial denture prosthesis. Impression of prepared teeth and of the opposing arch can be recorded simultaneously by dual-arch trays, while the full arch metal trays are used for impressions of prepared teeth in one arch. To measure and compare the accuracy of working dies made from impressions with metal and plastic dual arch trays and metal full arch trays, for two viscosities of impression material and by changing the sequence of pour of working and non-working sides. A balanced design with independent samples was used to study the three variables (tray type, impression material viscosity, and pouring sequence). An impression made by dual arch trays and single arch trays were divided in to three groups (Group A-plastic dual arch tray, Group B-metal dual arch tray, Group C-full arch metal stock tray). Out of these three groups, two groups (Group A and B) were subdivided in to four subgroups each and one group (Group C) was subdivided in to two subgroups. A sample size of 30 was used in each subgroup yielding a total 300 impressions in three groups or ten subgroups. Impressions were made of a machined circular stainless steel die. All three dimensions (Occlusogingival, Mesiodistal, and Buccolingual) of the working dies as well as stainless steel standard die were measured three times, and the mean was used for the three standard sample values to which all working dies means were compared. Statistical analysis used for this study was a 3-factor analysis of variance with hypothesis testing at α =0.05. With respect to the selection of impression material viscosity statistically significant differences were found in the dies for the buccolingual and mesiodistal dimensions. Metal dual arch trays were slightly more accurate in the mesiodistal dimension in comparison to the plastic trays in reference of tray selection and

  2. Comparative Study of AC/DC High Voltage Transmissions%高压交直流输电比较研究

    Institute of Scientific and Technical Information of China (English)

    王红刚

    2011-01-01

    比较了高压交流输电和高压直流输电的差异,认为,输送同样的电能,高压直流输电损耗少的原因在于载流子在晶格势场中的能态低;由于载流子受到感应电场的作用,高压交流输电载流子在晶格势场中的能态将高于高压直流输电载流子的能态。不论高压交流输电还是高压直流输电都存在着趋肤效应,直流趋肤效应起源于载流子受到的霍尔电场力;交流趋肤效应起源于载流子除了受到霍尔电场力外,还受到了交变电场力的作用.%Comparing the differences between AC and DC high voltage transmissions,it is considered that the reason why the DC high voltage transmission has lower electrical loss in transmitting the same power is that its carriers have low energy state in lattice potential field.As the carriers being affected by induced electric field,carriers of AC will have higher energy state than that of DC in lattice potential field.No matter AC or DC high voltage transmission there is skin effect.The DC skin effect originates from Hall electric field force acting on the carriers,while the AC skin effect originates from not only Hall electric field,but the role of alternating electric field force.

  3. Comparing Single and Dual Console Systems in the Robotic Surgical Training of Graduating OB/GYN Residents in the United States

    Directory of Open Access Journals (Sweden)

    Emad Mikhail

    2016-01-01

    Full Text Available Objective. To assess the impact of a single versus dual console robotic system on the perceptions of program directors (PD and residents (RES towards robotic surgical training among graduating obstetrics and gynecology residents. Design. An anonymous survey was developed using Qualtrics, a web-based survey development and administration system, and sent to obstetrics and gynecology program directors and graduating residents. Participants. 39 program directors and 32 graduating residents (PGY4. Results. According to residents perception, dual console is utilized in about 70% of the respondents’ programs. Dual console system programs were more likely to provide a robotics training certificate compared to single console programs (43.5% versus 0%, p=0.03. A greater proportion of residents graduating from a dual console program perform more than 20 robotic-assisted total laparoscopic hysterectomies, 30% versus 0% (p=0.15. Conclusions. Utilization of dual console system increased the likelihood of obtaining robotic training certification without significantly increasing the case volume of robotic-assisted total laparoscopic hysterectomy.

  4. Comparing Single and Dual Console Systems in the Robotic Surgical Training of Graduating OB/GYN Residents in the United States.

    Science.gov (United States)

    Mikhail, Emad; Salemi, Jason L; Hart, Stuart; Imudia, Anthony N

    2016-01-01

    Objective. To assess the impact of a single versus dual console robotic system on the perceptions of program directors (PD) and residents (RES) towards robotic surgical training among graduating obstetrics and gynecology residents. Design. An anonymous survey was developed using Qualtrics, a web-based survey development and administration system, and sent to obstetrics and gynecology program directors and graduating residents. Participants. 39 program directors and 32 graduating residents (PGY4). Results. According to residents perception, dual console is utilized in about 70% of the respondents' programs. Dual console system programs were more likely to provide a robotics training certificate compared to single console programs (43.5% versus 0%, p = 0.03). A greater proportion of residents graduating from a dual console program perform more than 20 robotic-assisted total laparoscopic hysterectomies, 30% versus 0% (p = 0.15). Conclusions. Utilization of dual console system increased the likelihood of obtaining robotic training certification without significantly increasing the case volume of robotic-assisted total laparoscopic hysterectomy.

  5. Comparative MD Simulations Indicate a Dual Role for Arg1323.50 in Dopamine-Dependent D2R Activation.

    Directory of Open Access Journals (Sweden)

    Ralf C Kling

    Full Text Available Residue Arg3.50 belongs to the highly conserved DRY-motif of class A GPCRs, which is located at the bottom of TM3. On the one hand, Arg3.50 has been reported to help stabilize the inactive state of GPCRs, but on the other hand has also been shown to be crucial for stabilizing active receptor conformations and mediating receptor-G protein coupling. The combined results of these studies suggest that the exact function of Arg3.50 is likely to be receptor-dependent and must be characterized independently for every GPCR. Consequently, we now present comparative molecular-dynamics simulations that use our recently described inactive-state and Gα-bound active-state homology models of the dopamine D2 receptor (D2R, which are either bound to dopamine or ligand-free, performed to identify the function of Arg1323.50 in D2R. Our results are consistent with a dynamic model of D2R activation in which Arg1323.50 adopts a dual role, both by stabilizing the inactive-state receptor conformation and enhancing dopamine-dependent D2R-G protein coupling.

  6. Single electron counting using a dual MCP assembly

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yuzhen [School of Physics, Nanjing University, Nanjing 210093 (China); Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); State Key Laboratory of Particle Detection and Electronics, Beijing 100049 (China); Liu, Shulin, E-mail: liusl@ihep.ac.cn [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); State Key Laboratory of Particle Detection and Electronics, Beijing 100049 (China); Zhao, Tianchi, E-mail: tianchi@u.washington.edu [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); State Key Laboratory of Particle Detection and Electronics, Beijing 100049 (China); Department of Physics, University of Washington, Seattle, WA 98195 (United States); Yan, Baojun; Wang, Peiliang [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); State Key Laboratory of Particle Detection and Electronics, Beijing 100049 (China); Yu, Yang [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); State Key Laboratory of Particle Detection and Electronics, Beijing 100049 (China); School of Science, Xi’an University of Technology, Xi’an 710048 (China); Lei, Xiangcui [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); State Key Laboratory of Particle Detection and Electronics, Beijing 100049 (China); Yang, Luping [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); State Key Laboratory of Particle Detection and Electronics, Beijing 100049 (China); School of Physics and Electronics, Henan University, Kaifeng 475004 (China); Wen, Kaile [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); State Key Laboratory of Particle Detection and Electronics, Beijing 100049 (China); Qi, Ming [School of Physics, Nanjing University, Nanjing 210093 (China); and others

    2016-09-11

    The gain, pulse height resolution and peak-to-valley ratio of single electrons detected by using a Chevron configured Microchannel Plate (MCP) assembly are studied. The two MCPs are separated by a 280 µm gap and are biased by four electrodes. The purpose of the study is to determine the optimum bias voltage arrangements for single electron counting. By comparing the results of various bias voltage combinations, we conclude that good performance for the electron counting can be achieved by operating the MCP assembly in saturation mode. In addition, by applying a small reverse bias voltage across the gap while adjusting the bias voltages of the MCPs, optimum performance of electron counting can be obtained. - Highlights: • Dual MCPs assembly with four electrodes using different voltage combinations has been investigated for single electron counting. • Both the MCP voltages and the gap voltage can affect the gain, pulse height resolution and P/V ratio. • A high gain of the first stage MCP, a saturation mode of the second stage MCP and an appropriately reverse gap voltage can improve the resolution greatly. • The optimum voltage arrangements is significant for the design of MCP detectors in single electron counting applications.

  7. Comparing surficial sediments maps interpreted by experts with dual-frequency acoustic backscatter on the Scotian Shelf, Canada

    Science.gov (United States)

    Cuff, Andrew; Anderson, John T.; Devillers, Rodolphe

    2015-11-01

    Understanding seabed properties is increasingly important to support policy in the marine environment. Such knowledge can be gained from diverse methods, ranging from more traditional expert-interpretations of acoustic and ground-truth data, to maps resulting from fully quantitative analyses of acoustic data. This study directly compares surficial geology maps created through expert-interpretations to near-nadir acoustic backscatter data from two frequencies (38 kHz and 120 kHz) collected using single beam echosounders (SBES) for two 5×1 km study areas on the Scotian Shelf, Canada. Statistical methods were used to analyze and classify both single and dual-frequency acoustic backscatter for comparisons. In particular, spatial scaling of acoustic backscatter responses and acoustic classes created using acoustic seabed classification (ASC) is compared between frequencies and to interpreted sediment units (ISUs) which make up surficial geology maps produced by experts. Seabed morphology layers were included in an ASC approach to reflect the morphological components included in the interpreted geological maps. Results confirmed that higher frequencies and coarser grain sizes generally produced higher backscatter, while more heterogeneous and rougher seabeds produced variable backscatter. Differing acoustic responses within similar substrate units suggest fundamental seabed variations not reflected in the geological interpretations. Spatial scaling of sand and gravel substrates from 38 kHz frequency were closer than the 120 kHz frequency to the spatial scaling of the interpreted geological map. Variable grain size in the sediment volume and surface morphology are both presented as possible reasons for frequency differences. While both frequencies had similar general responses, differences in frequency responses of backscatter occurred at scales of tens to hundreds of meters. Results presented here emphasize the importance of multi-scale seabed mapping and additional

  8. Characterization of Small Focal Renal Lesions: Diagnostic Accuracy with Single-Phase Contrast-enhanced Dual-Energy CT with Material Attenuation Analysis Compared with Conventional Attenuation Measurements.

    Science.gov (United States)

    Marin, Daniele; Davis, Drew; Roy Choudhury, Kingshuk; Patel, Bhavik; Gupta, Rajan T; Mileto, Achille; Nelson, Rendon C

    2017-09-01

    Purpose To determine whether single-phase contrast material-enhanced dual-energy material attenuation analysis improves the characterization of small (1-4 cm) renal lesions compared with conventional attenuation measurements by using histopathologic analysis and follow-up imaging as the clinical reference standards. Materials and Methods In this retrospective, HIPAA-compliant, institutional review board-approved study, 136 consecutive patients (95 men and 41 women; mean age, 54 years) with 144 renal lesions (111 benign, 33 malignant) measuring 1-4 cm underwent single-energy unenhanced and contrast-enhanced dual-energy computed tomography (CT) of the abdomen. For each renal lesion, attenuation measurements were obtained; attenuation change of greater than or equal to 15 HU was considered evidence of enhancement. Dual-energy attenuation measurements were also obtained by using iodine-water, water-iodine, calcium-water, and water-calcium material basis pairs. Mean lesion attenuation values and material densities were compared between benign and malignant renal lesions by using the two-sample t test. Diagnostic accuracy of attenuation measurements and dual-energy material densities was assessed and validated by using 10-fold cross-validation to limit the effect of optimistic bias. Results By using cross-validated optimal thresholds at 100% sensitivity, iodine-water material attenuation images significantly improved specificity for differentiating between benign and malignant renal lesions compared with conventional enhancement measurements (93% [103 of 111]; 95% confidence interval: 86%, 97%; vs 81% [90 of 111]; 95% confidence interval: 73%, 88%) (P = .02). Sensitivity with iodine-water and calcium-water material attenuation images was also higher than that with conventional enhancement measurements, although the difference was not statistically significant. Conclusion Contrast-enhanced dual-energy CT with material attenuation analysis improves specificity for

  9. A Single Switch Dual Output Non-Isolated Boost Converter

    DEFF Research Database (Denmark)

    Klimczak, Pawel; Munk-Nielsen, Stig

    2008-01-01

    very simple dual output non-isolated boost converter is presented. Single active switch is used to control both, positive and negative output voltages. The converter is desired to boost unregulated low input voltage 25-50 Vdc to regulated high voltage ±400 Vdc in dual dc-link. In this paper proposed...

  10. Development of a New Cascade Voltage-Doubler for Voltage Multiplication

    OpenAIRE

    Arash Toudeshki; Norman Mariun; Hashim Hizam; Noor Izzri Abdul Wahab

    2014-01-01

    For more than eight decades, cascade voltage-doubler circuits are used as a method to produce DC output voltage higher than the input voltage. In this paper, the topological developments of cascade voltage-doublers are reviewed. A new circuit configuration for cascade voltage-doubler is presented. This circuit can produce a higher value of the DC output voltage and better output quality compared to the conventional cascade voltage-doubler circuits, with the same number of stages.

  11. Design and Fabrication of Novel Dual-Base Negative-Differential Resistance Heterojunction Bipolar Transistor

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Based on planar Si dual-base transistor conception, a novel mesa dual-base heterojunction bipolar transistor (HBT) is designed and fabricated. Molecule beam extension, selective wet chemical etching, common contact photolithography and metal lift-off technique are adopted in the process. The device has particular and distinct voltage-controlled negative differential resistance (NDR) and photo-controlled NDR. The highest peak-to-vally current rate of the voltage-controlled NDR is larger than 148 and the peak current varies with the increase of collector voltage. The device features high speed and high frequency characteristics derived from HBT and intrinsic bistability and self-latching characteristics due to NDR. A single dual-base HBT can be seen as an integration of NDR device, HBT and photoconductive device. Compared with common HBT,the groove is the key factor producing NDR.

  12. Compare and Research the Radiation dose and Image Quality on Dual Energy Dual Source Spiral CT Pulmonary Artery Imaging%双源双能量螺旋CT肺动脉成像辐射剂量与图像质量的对比研究

    Institute of Scientific and Technical Information of China (English)

    张筱双

    2015-01-01

    Objective To compare the difference of the radiation dose and image quality on dual energy dual source spiral CT pulmonary artery imaging.Methods 80 cases of pulmonary embolism patients in our hospital were selected as the research object. All patients were willing to accept CTPA examination, 40 cases in each group. A group used tube voltage 80/Sn140KV check, B group used tube voltage 100/Sn140KV examination, compared two groups’ pulmonary artery, pulmonary artery, the dorsal fat CT value, other indicators and CT image treatment subjective evaluation, calculation of signal to noise ratio (SNR), contrast to noise ratio (CNR) and effective dose (ED).Results The average CT value of A group’s pulmonary artery, mean CNR index were signiifcantly higher than those of group B(P<0.05), subjective CT image quality evaluation results show score were not signiifcantly different between A group and B group, but ed level of group A was signiifcantly lower than that of group B(P<0.05).Conclusion Dual source dual energy CT pulmonary artery imaging using scanning 80/Sn140 kV has high value in the diagnosis of CT images at the same time, and can greatly reduce the radiation dose during examination, which has clinical application and popularization value.%目的:对比第二代双源双能量螺旋CT肺动脉成像(CTPA)不同辐射剂量下CT图像质量的差异性。方法筛选我院收治的肺栓塞患者80例,作为研究对象。所有患者均自愿接受CTPA检查,每组40例,其中A组管电压80/Sn140KV检查,B组管电压100/Sn140KV检查,比较两组患者肺动脉主干、肺动脉段、背部脂肪CT值等指标,并对CT影像治疗进行主观评分,计算信噪比(SNR)、对比噪声比(CNR)、有效剂量(ED)等。结果 A组患者肺动脉平均CT值、平均CNR指标明显高于B组(P<0.05),主观CT影像质量评价结果显示A组与B组评分无显著差异,但A组ED水平明显低于B组(P<0.05)。结论

  13. Accuracy of Percutaneous Pedicle Screw Insertion Technique with Conventional Dual Fluoroscopy Units and a Retrospective Comparative Study Based on Surgeon Experience.

    Science.gov (United States)

    Nakahara, Masayuki; Yasuhara, Takao; Inoue, Takafumi; Takahashi, Yuichi; Kumamoto, Shinji; Hijikata, Yasukazu; Kusumegi, Akira; Sakamoto, Yushi; Ogawa, Koichi; Nishida, Kenki

    2016-06-01

    Study Design Retrospective comparative study. Objective To evaluate the accuracy of percutaneous pedicle screw (PPS) placement and intraoperative imaging time using dual fluoroscopy units and their differences between surgeons with more versus less experience. Methods One hundred sixty-one patients who underwent lumbar fusion surgery were divided into two groups, A (n = 74) and B (n = 87), based on the performing surgeon's experience. The accuracy of PPS placement and radiation time for PPS insertion were compared. PPSs were inserted with classic technique under the assistance of dual fluoroscopy units placed in two planes. The breach definition of PPS misplacement was based on postoperative computed tomography (grade I: no breach; grade II: experience.

  14. Some specific features in the development of the dual in Slovene as compared to other Slavic languages

    Directory of Open Access Journals (Sweden)

    Aleksandra Derganc

    1994-12-01

    Full Text Available Tesnierè's work "Les formes du duel en Slovène" and his "Atlas linguistique pour servir à l'étude du duel en slovène" has remained the basic work to consult in dealing with the category of the dual in Slovene and has been used as well by linguists researching this category in other Slavic languages. Tesnieère himself explained the reason for doing his research: the dual greatly interested his teacher A. Meillet and Tesniere wanted to study this category and the way it was disappearing in a modern European language, the choice being very limited (he mentioned certain speakers of Lithuanian, and three Slavic languages: Slovene, Slovincian 1 and Lower Sorbian; Tesnière 1925a: VIII; all references in this paper are to Tesnière 1925a.

  15. A randomized, comparative study of dual therapy (doxycycline–rifampin versus triple therapy (doxycycline–rifampin–levofloxacin for treating acute/subacute brucellosis

    Directory of Open Access Journals (Sweden)

    Ahmad Hasanain

    Full Text Available Abstract Aim The aim of this study was to compare both the efficacy and safety profile of the WHO-recommended, dual therapy (doxycycline–rifampin to a quinolone-based, triple therapy (doxycycline–rifampin–levofloxacin for treating acute/subacute brucellosis. Patients and methods We studied 107 consecutive, naïve patients with acute/subacute brucellosis admitted to Assiut University Hospital. Patients were randomly allocated to receive the dual therapy of doxycycline–rifampin (group-A or to receive the triple therapy of doxycycline–rifampin–levofloxacin (group-B. Acute/subacute brucellosis was diagnosed based on the presence of: (1 contact with animals or fresh animal products, (2 suggestive clinical manifestations of less than one-year duration, and (3 positive antibody titer (1:160 by standard tube agglutination test. Results There was no significant difference between the two groups regarding their demographic data. Fever was the most frequent manifestation (96.3%. Epigastric pain was the most frequent adverse effect of treatment (12.1%. Group-A patients had a significantly higher relapse rate compared to group-B patients (22.6% versus 9.3%, p-value = 0.01. The rate of treatment adverse effects was higher among group-B patients, although not reaching statistical significance (20.4% versus 11.3%, p-value = 0.059. Conclusions Adding levofloxacin to the dual therapy for acute/subacute brucellosis (doxycycline–rifampin may increase its efficacy in terms of lowering the relapse rate of the disease. Further, larger scale studies are needed before considering modifying the standard, dual therapy for brucellosis.

  16. Comparative study of the distribution of the alpha-subunits of voltage-gated sodium channels in normal and axotomized rat dorsal root ganglion neurons.

    Science.gov (United States)

    Fukuoka, Tetsuo; Kobayashi, Kimiko; Yamanaka, Hiroki; Obata, Koichi; Dai, Yi; Noguchi, Koichi

    2008-09-10

    We compared the distribution of the alpha-subunit mRNAs of voltage-gated sodium channels Nav1.1-1.3 and Nav1.6-1.9 and a related channel, Nax, in histochemically identified neuronal subpopulations of the rat dorsal root ganglia (DRG). In the naïve DRG, the expression of Nav1.1 and Nav1.6 was restricted to A-fiber neurons, and they were preferentially expressed by TrkC neurons, suggesting that proprioceptive neurons possess these channels. Nav1.7, -1.8, and -1.9 mRNAs were more abundant in C-fiber neurons compared with A-fiber ones. Nax was evenly expressed in both populations. Although Nav1.8 and -1.9 were preferentially expressed by TrkA neurons, other alpha-subunits were expressed independently of TrkA expression. Actually, all IB4(+) neurons expressed both Nav1.8 and -1.9, and relatively limited subpopulations of IB4(+) neurons (3% and 12%, respectively) expressed Nav1.1 and/or Nav1.6. These findings provide useful information in interpreting the electrophysiological characteristics of some neuronal subpopulations of naïve DRG. After L5 spinal nerve ligation, Nav1.3 mRNA was up-regulated mainly in A-fiber neurons in the ipsilateral L5 DRG. Although previous studies demonstrated that nerve growth factor (NGF) and glial cell-derived neurotrophic factor (GDNF) reversed this up-regulation, the Nav1.3 induction was independent of either TrkA or GFRalpha1 expression, suggesting that the induction of Nav1.3 may be one of the common responses of axotomized DRG neurons without a direct relationship to NGF/GDNF supply. (c) 2008 Wiley-Liss, Inc.

  17. Optimization of kV Selection on Third-generation High-pitch Dual-source Coronary CT Angiography Using Ultra-low Contrast Media Protocols in Patients with Body Mass Index between 20-30 kg/m(2) under Automatic Tube Voltage Selection.

    Science.gov (United States)

    Wang, Ming; Yi, Yan; Cao, Jian; Wang, Yining; Qi, Bing; Ma, Shuo; Wang, Yun

    2017-02-20

    Objective To investigate the application of automatic tube voltage selection (CARE-kV)coronary CT angiography (CCTA)using ultra-low contrast media (CM)protocols in patients with body mass index (BMI)between 20 kg/m(2) and 30 kg/m(2) on third-generation dual-source CT (DSCT). Methods We prospectively included 134 consecutive patients with BMI between 20 kg/m(2) and 30 kg/m(2)who underwent CARE-kV prospective high-pitch CCTA on third-generation DSCT using the ultra-low CM protocols and divided them into two groups according to the CARE-kV results:70 kV group(n=91):65 patients with normal BMI(20 kg/m(2)≤BMI≤25 kg/m(2))and 26 patients with high BMI(25 kg/m(2)image quality (IQ),and results of patients in each group and subgroup were evaluated and compared.ResultsThe ED of 70 kV group was(0.24±0.04)mSv,which was 53% lower(H=3.37,P=0.02)than that of 80 kV group [(0.51±0.05)mSv]. No significant difference of CNR and SNR had been found in normal BMI patients(H=1.81,P=0.23)and high BMI patients (H=0.91,P=0.84)among 70 kV group and 80 kV group,as well as the subjective IQ in normal BMI patients(Z=0.79,P=0.76)and high BMI patients (Z=0.77,P=0.81)among 70 kV group and 80 kV group. Conclusion sWhen patients with BMI between 20 kg/m(2) and 30 kg/m(2) receive CARE-kV prospective high-pitch CCTA on third-generation DSCT,the CARE-kV results for a portion of patients may be higher than other patients with the same BMI level,so as to guarantee the equivalent IQ. The CARE-kV can help to select the patients' optimal tube voltage value more accurately and reasonably.

  18. 阻尼振荡波电压和工频电压下XLPE电缆局部放电特性的对比研究%Comparative Study on Partial Discharge Characteristics of XLPE Cable under Damped Oscillating Wave Voltage and AC Voltage

    Institute of Scientific and Technical Information of China (English)

    薛荣; 张龙; 黄志伟; 张伟; 李洪杰

    2015-01-01

    The partial discharge characteristics of four defects in heat-shrinkable cable accessories, which were termination without stress tube, incorrect use of insulation tape as semi-conductive adhesive tape in the middle joint, void and metal particles on the surface of XLPE insulation, were studied by AC volt-age method and damped oscillating wave voltage method. The partial discharge inception voltage and pat-terns under damped oscillating wave voltage and AC voltage were compared. The results show that the two methods are consistent in the study of partial discharge characteristics, and there are obvious differ-ences in the partial discharge statistical characteristics of various defects.%采用工频电压法和阻尼振荡波电压法研究热缩式电缆附件在4种缺陷情况下的局部放电特性,对比分析两种电压情况下的局部放电起始电压和局放模式。结果表明:两种方法在局部放电特性研究中具有一致性,各种缺陷的局部放电统计特征具有较为明显的差异。

  19. Accurate Switched-Voltage voltage averaging circuit

    OpenAIRE

    金光, 一幸; 松本, 寛樹

    2006-01-01

    Abstract ###This paper proposes an accurate Switched-Voltage (SV) voltage averaging circuit. It is presented ###to compensated for NMOS missmatch error at MOS differential type voltage averaging circuit. ###The proposed circuit consists of a voltage averaging and a SV sample/hold (S/H) circuit. It can ###operate using nonoverlapping three phase clocks. Performance of this circuit is verified by PSpice ###simulations.

  20. Application of colon capsule endoscopy (CCE to evaluate the whole gastrointestinal tract: a comparative study of single-camera and dual-camera analysis

    Directory of Open Access Journals (Sweden)

    Remes-Troche JM

    2013-09-01

    Full Text Available José María Remes-Troche,1 Victoria Alejandra Jiménez-García,2 Josefa María García-Montes,2 Pedro Hergueta-Delgado,2 Federico Roesch-Dietlen,1 Juan Manuel Herrerías-Gutiérrez2 1Digestive Physiology and Motility Lab, Medical Biological Research Institute, Universidad Veracruzana, Veracruz, México; 2Gastroenterology Service, Virgen Macarena University Hospital, Seville, Spain Background and study aims: Colon capsule endoscopy (CCE was developed for the evaluation of colorectal pathology. In this study, our aim was to assess if a dual-camera analysis using CCE allows better evaluation of the whole gastrointestinal (GI tract compared to a single-camera analysis. Patients and methods: We included 21 patients (12 males, mean age 56.20 years submitted for a CCE examination. After standard colon preparation, the colon capsule endoscope (PillCam Colon™ was swallowed after reinitiation from its “sleep” mode. Four physicians performed the analysis: two reviewed both video streams at the same time (dual-camera analysis; one analyzed images from one side of the device (“camera 1”; and the other reviewed the opposite side (“camera 2”. We compared numbers of findings from different parts of the entire GI tract and level of agreement among reviewers. Results: A complete evaluation of the GI tract was possible in all patients. Dual-camera analysis provided 16% and 5% more findings compared to camera 1 and camera 2 analysis, respectively. Overall agreement was 62.7% (kappa = 0.44, 95% CI: 0.373–0.510. Esophageal (kappa = 0.611 and colorectal (kappa = 0.595 findings had a good level of agreement, while small bowel (kappa = 0.405 showed moderate agreement. Conclusion: The use of dual-camera analysis with CCE for the evaluation of the GI tract is feasible and detects more abnormalities when compared with single-camera analysis. Keywords: capsule endoscopy, colon, gastrointestinal tract, small bowel

  1. Comparative study of gas diffusion in subsurface using dual-gas tracer SF6 and halon 1211

    Directory of Open Access Journals (Sweden)

    Wang Weixian

    2016-01-01

    Full Text Available Field experiment and soil column test were performed to study the gas diffusion in the soil subsurface using dual-gas tracer SF6 and halon 1211. Gas samples collected from pre-set sampling sites were measured. These two tracer gases showed the similar trend. At the different directions from injecting site, concentrations increased rapidly at the beginning, the peak value concentration of SF6 was higher than that of halon 1211, implied SF6 diffuse further. At the different depth from injecting site, tracer gases preferred to transport horizontal or downwards rather than upwards, meant gravity settling was an important factor affecting the gas diffusion. The effect of temperature and water content on the gas diffusion revealed that gases migrated fast obviously with the temperature increase, the change of water content had influence slightly. Gas desorption test indicated that much more halon 1211 was adsorbed on the soil, which led the diffusion process slow down.

  2. Comparative evaluation of shear bond strength of three resin based dual-cure core build-up materials: An In-vitro study

    Directory of Open Access Journals (Sweden)

    Gaurav Jain

    2015-01-01

    Full Text Available Aim: The in-vitro study compared the shear bond strength (SBS of three recently introduced dual-cure resin based core build-up materials namely ParaCore, FluoroCore, and MultiCore. Materials and Methods: One hundred twenty extracted permanent human mandibular molar teeth were taken and sectioned horizontally beneath the dentinoenamel junction to expose the coronal dentin. The specimens obtained were divided into three main groups based on the materials used and then further divided into four sub-groups based on time interval with ten samples each. The dentin surface was treated with the respective adhesives of the groups and then bulk filled with core build-up materials. The attained samples were than subjected to shear loading in Instron Universal Testing Machine. The data were tabulated and statistically analyzed using analysis of variance (ANOVA, Tukey′s HSD, and Levene′s test. Results: The mean SBS was highest in MultiCore at all time periods as compared to FluoroCore and ParaCore and was also higher at 48 h thermocycling in all three groups studied. Conclusion: MultiCore dual-cure resin based core build-up material showed the highest mean SBS as compared to FluoroCore and ParaCore. SBS was not negatively affected by thermocycling.

  3. Comparative evaluation of shear bond strength of three resin based dual-cure core build-up materials: An In-vitro study.

    Science.gov (United States)

    Jain, Gaurav; Narad, Aditi; Boruah, Lalit C; Rajkumar, Balakrishnan

    2015-01-01

    The in-vitro study compared the shear bond strength (SBS) of three recently introduced dual-cure resin based core build-up materials namely ParaCore, FluoroCore, and MultiCore. One hundred twenty extracted permanent human mandibular molar teeth were taken and sectioned horizontally beneath the dentinoenamel junction to expose the coronal dentin. The specimens obtained were divided into three main groups based on the materials used and then further divided into four sub-groups based on time interval with ten samples each. The dentin surface was treated with the respective adhesives of the groups and then bulk filled with core build-up materials. The attained samples were than subjected to shear loading in Instron Universal Testing Machine. The data were tabulated and statistically analyzed using analysis of variance (ANOVA), Tukey's HSD, and Levene's test. The mean SBS was highest in MultiCore at all time periods as compared to FluoroCore and ParaCore and was also higher at 48 h thermocycling in all three groups studied. MultiCore dual-cure resin based core build-up material showed the highest mean SBS as compared to FluoroCore and ParaCore. SBS was not negatively affected by thermocycling.

  4. Comparative utilization of pharmacotherapy for alcohol use disorder and other psychiatric disorders among U.S. Veterans Health Administration patients with dual diagnoses.

    Science.gov (United States)

    Rubinsky, Anna D; Chen, Cheng; Batki, Steven L; Williams, Emily C; Harris, Alex H S

    2015-10-01

    Patients with alcohol use disorder (AUD) and another co-occurring psychiatric disorder are a vulnerable population with high symptom severity. Such patients may benefit from a full arsenal of treatment options including pharmacotherapy. Receipt of AUD pharmacotherapy is generally very low despite recommendations that it be made available to every patient with AUD, including those with co-occurring disorders. Little is known about pharmacotherapy rates for AUD compared to other psychiatric disorders among patients with dual diagnoses. This study compared rates of pharmacotherapy for AUD to those for non-substance use psychiatric disorders and tobacco use disorder among patients with dual diagnoses in the U.S. Veterans Affairs (VA) healthcare system. VA data were used to identify patients with AUD and another psychiatric disorder in fiscal year 2012, and to estimate the proportion receiving pharmacotherapy for AUD and for each comorbid condition. Among subsets of patients with AUD and co-occurring schizophrenic, bipolar, posttraumatic stress or major depressive disorder, receipt of medications for AUD ranged from 7% to 11%, whereas receipt of medications for the comorbid disorder ranged from 69% to 82%. Among patients with AUD and co-occurring tobacco use disorder, 6% received medication for their AUD and 34% for their tobacco use disorder. Among patients with dual diagnoses, rates of pharmacotherapy for AUD were far lower than those for the comorbid disorders and contrary to evidence that medications for AUD are effective. Additional system-wide implementation efforts to identify and address patient- and provider-level barriers are needed to increase AUD pharmacotherapy in this high-need population.

  5. Voltage Dependence of Supercapacitor Capacitance

    Directory of Open Access Journals (Sweden)

    Szewczyk Arkadiusz

    2016-09-01

    Full Text Available Electronic Double-Layer Capacitors (EDLC, called Supercapacitors (SC, are electronic devices that are capable to store a relatively high amount of energy in a small volume comparing to other types of capacitors. They are composed of an activated carbon layer and electrolyte solution. The charge is stored on electrodes, forming the Helmholtz layer, and in electrolyte. The capacitance of supercapacitor is voltage- dependent. We propose an experimental method, based on monitoring of charging and discharging a supercapacitor, which enables to evaluate the charge in an SC structure as well as the Capacitance-Voltage (C-V dependence. The measurement setup, method and experimental results of charging/discharging commercially available supercapacitors in various voltage and current conditions are presented. The total charge stored in an SC structure is proportional to the square of voltage at SC electrodes while the charge on electrodes increases linearly with the voltage on SC electrodes. The Helmholtz capacitance increases linearly with the voltage bias while a sublinear increase of total capacitance was found. The voltage on SC increases after the discharge of electrodes due to diffusion of charges from the electrolyte to the electrodes. We have found that the recovery voltage value is linearly proportional to the initial bias voltage value.

  6. Voltage stability dynamical analysis by comparing static and dynamical loads; Estudio dinamico de estabilidad de tension comparando modelos de carga estatica y carga dinamica

    Energy Technology Data Exchange (ETDEWEB)

    Aromataris, Luis [Universidad Nacional de Rio Cuarto (UNRC) (Argentina); Arnera, Patricia; Riubrugent, Jean [Universidad Nacional de La Plata, Buenos Aires (Argentina). Facultad de Ingenieria. Instituto de Investigaciones Tecnologicas para Redes y Equipos Electricos

    2001-07-01

    This work investigate the impact produced by the load model on the voltage stability analysis of an electric system. Qualitative and quantitative analyses are approached in connection with the effects of modeling the electric loads by both dynamical and static way. Also it is highlighted the importance of using dynamical models of load, mainly when it is composed by motors.

  7. Energy reduction through voltage scaling and lightweight checking

    Science.gov (United States)

    Kadric, Edin

    As the semiconductor roadmap reaches smaller feature sizes and the end of Dennard Scaling, design goals change, and managing the power envelope often dominates delay minimization. Voltage scaling remains a powerful tool to reduce energy. We find that it results in about 60% geomean energy reduction on top of other common low-energy optimizations with 22nm CMOS technology. However, when voltage is reduced, it becomes easier for noise and particle strikes to upset a node, potentially causing Silent Data Corruption (SDC). The 60% energy reduction, therefore, comes with a significant drop in reliability. Duplication with checking and triple-modular redundancy are traditional approaches used to combat transient errors, but spending 2--3x the energy for redundant computation can diminish or reverse the benefits of voltage scaling. As an alternative, we explore the opportunity to use checking operations that are cheaper than the base computation they are guarding. We devise a classification system for applications and their lightweight checking characteristics. In particular, we identify and evaluate the effectiveness of lightweight checks in a broad set of common tasks in scientific computing and signal processing. We find that the lightweight checks cost only a fraction of the base computation (0-25%) and allow us to recover the reliability losses from voltage scaling. Overall, we show about 50% net energy reduction without compromising reliability compared to operation at the nominal voltage. We use FPGAs (Field-Programmable Gate Arrays) in our work, although the same ideas can be applied to different systems. On top of voltage scaling, we explore other common low-energy techniques for FPGAs: transmission gates, gate boosting, power gating, low-leakage (high-Vth) processes, and dual-V dd architectures. We do not scale voltage for memories, so lower voltages help us reduce logic and interconnect energy, but not memory energy. At lower voltages, memories become dominant

  8. Coordinated Voltage Control of Active Distribution Network

    Directory of Open Access Journals (Sweden)

    Xie Jiang

    2016-01-01

    Full Text Available This paper presents a centralized coordinated voltage control method for active distribution network to solve off-limit problem of voltage after incorporation of distributed generation (DG. The proposed method consists of two parts, it coordinated primal-dual interior point method-based voltage regulation schemes of DG reactive powers and capacitors with centralized on-load tap changer (OLTC controlling method which utilizes system’s maximum and minimum voltages, to improve the qualified rate of voltage and reduce the operation numbers of OLTC. The proposed coordination has considered the cost of capacitors. The method is tested using a radial edited IEEE-33 nodes distribution network which is modelled using MATLAB.

  9. Assessment of aortic stenosis after aortic valve replacement. Comparative evaluation of dual-source CT and echocardiography; Quantitative Evaluation der Aortenklappenoeffnungsflaeche mit der Dual-Source-CT und Korrelation mit der 2D-Echokardiografie. Initiale Ergebnisse

    Energy Technology Data Exchange (ETDEWEB)

    Saam, T.; Minaifar, N.; Becker, C.; Reiser, M.; Nikolaou, K. [Ludwig-Maximilians-Univ. Muenchen (Germany). Inst. fuer Klinische Radiologie; Oberhoffer, M.; Rist, C.; Vogt, F.; Reichart, B. [Ludwig-Maximilians-Univ. Muenchen (Germany). Herzchirurgische Klinik und Poliklinik

    2008-06-15

    Purpose: To prospectively evaluate whether planimetric measurements of aortic valve area (AVA) with dual-source computed tomography (DSCT) correlate with measurements obtained by echocardiography and to correlate the amount of calcification of the aortic valve with AVA in a group of patients after aortic valve replacement. Materials and Method: 23 patients underwent dual-source computed tomography (DSCT) of the heart (Somatom Definition, Siemens Medical Solutions, Forchheim, Germany), without heart rate control (heart rate 52-113 beats/minute). All patients had undergone aortic valve replacement (homografts, mean time after surgery: 7{+-}3 years). The AVA of the transplanted aortic valve graft was measured planimetrically by means of DSCT and compared with echocardiography as a standard of reference, to exclude post-surgical restenosis of the valve. Maximum AVA in systole planimetrically measured with CT was compared with calculated AVA values determined with the continuity equation, using transvalvular pressure gradients. The amount of calcification of the aortic valve was quantified and correlated (Spearman's R) with the AVA. To assess intra- and inter-reader reproducibility, the DCST data was re-analyzed by two readers 4 weeks after the initial review. Results: All DSCT datasets were of diagnostic image quality concerning valve depiction. The mean AVA as measured by DSCT was 2.7{+-}0.9 cm{sup 2} compared to 1.8{+-}0.5 cm{sup 2} by echocardiography (p<0.05). The planimetric evaluation of the CT data as compared to results of echocardiography showed a significant correlation of the results (Pearson's correlation coefficient R=0.78, p<0.001). Intra- and inter-reader reproducibility was good with intra-class correlation coefficients of 0.86 and 0.81, respectively (p<0.001). There was a significant negative correlation between the amount of aortic valve calcification and AVA as measured by echocardiography (R=-0.42; p<0.05) and as measured by DSCT (R=-0

  10. Virtual non-contrast dual-energy CT compared to single-energy CT of the urinary tract: a prospective study

    Energy Technology Data Exchange (ETDEWEB)

    Lundin, Margareta; Liden, Mats; Geijer, Haakan; Andersson, Torbjoern [Dept. of Radiology, Oerebro Univ. Hospital, Oerebro Univ., Oerebro (Sweden)], E-mail: margareta.lundin@orebroll.se; Magnuson, Anders [Clinical Epidemiology and Biostatistic Unit, Oerebro Univ. Hospital, Oerebro (Sweden); Mohammed, Ahmed Abdulilah [Dept. of Radiology, Linkoeping Univ. Hospital, Linkoeping (Sweden); Persson, Anders [CMIV Center for Medical Image Science and Visualization, Linkoeping (Sweden)

    2012-07-15

    Background. Dual-energy computed tomography (DECT) has been shown to be useful for subtracting bone or calcium in CT angiography and gives an opportunity to produce a virtual non-contrast-enhanced (VNC) image from a series where contrast agents have been given intravenously. High noise levels and low resolution have previously limited the diagnostic value of the VNC images created with the first generation of DECT. With the recent introduction of a second generation of DECT, there is a possibility of obtaining VNC images with better image quality at hopefully lower radiation dose compared to the previous generation. Purpose. To compare the image quality of the single-energy series to a VNC series obtained with a two generations of DECT scanners. CT of the urinary tract was used as a model. Material and Methods. Thirty patients referred for evaluation of hematuria were examined with an older system (Somatom Definition) and another 30 patients with a new generation (Somatom Definition Flash). One single-energy series was obtained before and one dual-energy series after administration of intravenous contrast media. We created a VNC series from the contrast-enhanced images. Images were assessed concerning image quality with a visual grading scale evaluation of the VNC series with the single-energy series as gold standard. Results. The image quality of the VNC images was rated inferior to the single-energy variant for both scanners, OR 11.5-67.3 for the Definition and OR 2.1-2.8 for the Definition Flash. Visual noise and overall quality were regarded as better with Flash than Definition. Conclusion. Image quality of VNC images obtained with the new generation of DECT is still slightly inferior compared to native images. However, the difference is smaller with the new compared to the older system.

  11. Comparative evaluation of shear bond strength, between IPS-Empress2 ceramics and three dual-cured resin cements

    Directory of Open Access Journals (Sweden)

    Hajimiragha H

    2006-06-01

    Full Text Available Background and Aim: Cementation is one of the most critical steps of the porcelain restoration technique. However, limited information is available concerning the bond strength of current ceramic bonding systems. The aim of this study was to evaluate the shear bond strength of three dual-cure resin cements to IPS-Empress2 ceramics. Materials and Methods: In this experimental study, 30 pairs of IPS-Empress 2 ceramic discs were fabricated with 10 and 8 mm diameters and 2.5 mm thickness. After sandblasting and ultrasonic cleaning, the surfaces of all specimens were etched with 9% hydrofluoric acid for 60 seconds. Then, the three groups of 10 bonded specimens were prepared ceramic bonding resin systems including Panavia F2, Variolink II and Rely X ARC. After storage in 37±1c water for 24 hours and thermocycling in 5c and 55c water for 500 cycles with 1-minute dwell time, the shear bond strengths were determined using Instron machine at speed of 0.5mm/min. Data were analyzed by One Way ANOVA test. For multiple paired comparisons, the Tukey HSD method was used. The mode of failure was evaluated by scanning electro microscope (SEM. P<0.05 was considered as the limit of significance. Result: Significant differences were found between different cement types (P<0.05. Variolink II provided the highest bonding values with IPS-Empress2. A combination of different modes of failure was observed. Conclusion: Based on the results of this study, according to the highest mode of cohesive failure, Variolink II seems to have the strongest bond with IPS-Empress2 ceramics.

  12. Bone densitometry by dual-energy X-ray absorptiometry (DXA in preterm newborns compared with full-term peers in the first six months of life

    Directory of Open Access Journals (Sweden)

    Virginia S. Quintal

    2014-12-01

    Full Text Available OBJECTIVES: To longitudinally assess bone mineral content (BMC, bone mineral density (BMD, and whole-body lean mass obtained through bone densitometry by dual-energy X-ray absorptiometry (DXA in preterm newborns (PTNs and compare them with full-term newborns (FTNs from birth to 6 months of corrected postnatal age. METHODS: A total of 28 adequate for gestational age (AGA newborns were studied: 14 preterm and 14 full-term newborns. DXA was used to determine BMC, BMD, and lean mass in three moments: 40 weeks corrected post-conceptual age, as well as 3 and 6 months of corrected postnatal age. PTNs had gestational age ≤ 32 weeks at birth and were fed their mother's own milk or milk from the human milk bank. RESULTS: All infants had an increase in BMC, BMD, and lean body mass values during the study. PTNs had lower BMC, BMD, and lean mass at 40 weeks of corrected post-conceptual age in relation to FTNs (p < 0.001, p < 0.001, p = 0.047, respectively. However, there was an acceleration in the mineralization process of PTNs, which was sufficient to achieve the normal values of FTNs at 6 months of corrected age. CONCLUSIONS: This study suggests that bone densitometry by dual-energy X-ray absorptiometry is a good method for the assessment of body composition parameters at baseline, and at the follow-up of these PTNs.

  13. Bone densitometry by dual-energy X-ray absorptiometry (DXA) in preterm newborns compared with full-term peers in the first six months of life.

    Science.gov (United States)

    Quintal, Virginia S; Diniz, Edna M A; Caparbo, Valeria de F; Pereira, Rosa M R

    2014-01-01

    To longitudinally assess bone mineral content (BMC), bone mineral density (BMD), and whole-body lean mass obtained through bone densitometry by dual-energy X-ray absorptiometry (DXA) in preterm newborns (PTNs) and compare them with full-term newborns (FTNs) from birth to 6 months of corrected postnatal age. A total of 28 adequate for gestational age (AGA) newborns were studied: 14 preterm and 14 full-term newborns. DXA was used to determine BMC, BMD, and lean mass in three moments: 40 weeks corrected post-conceptual age, as well as 3 and 6 months of corrected postnatal age. PTNs had gestational age ≤ 32 weeks at birth and were fed their mother's own milk or milk from the human milk bank. All infants had an increase in BMC, BMD, and lean body mass values during the study. PTNs had lower BMC, BMD, and lean mass at 40 weeks of corrected post-conceptual age in relation to FTNs (p<0.001, p<0.001, p=0.047, respectively). However, there was an acceleration in the mineralization process of PTNs, which was sufficient to achieve the normal values of FTNs at 6 months of corrected age. This study suggests that bone densitometry by dual-energy X-ray absorptiometry is a good method for the assessment of body composition parameters at baseline, and at the follow-up of these PTNs. Copyright © 2014 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

  14. Nonequilibrium atmospheric pressure plasma jet using a combination of 50 kHz/2 MHz dual-frequency power sources

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yong-Jie; Yuan, Qiang-Hua; Li, Fei; Wang, Xiao-Min; Yin, Gui-Qin; Dong, Chen-Zhong [Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province, College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070 (China)

    2013-11-15

    An atmospheric pressure plasma jet is generated by dual sinusoidal wave (50 kHz and 2 MHz). The dual-frequency plasma jet exhibits the advantages of both low frequency and radio frequency plasmas, namely, the long plasma plume and the high electron density. The radio frequency ignition voltage can be reduced significantly by using dual-frequency excitation compared to the conventional radio frequency without the aid of the low frequency excitation source. A larger operating range of α mode discharge can be obtained using dual-frequency excitation which is important to obtain homogeneous and low-temperature plasma. A larger controllable range of the gas temperature of atmospheric pressure plasma could also be obtained using dual-frequency excitation.

  15. Dual-energy CT in the assessment of mediastinal lymph nodes: Comparative study of virtual non-contrast and true non-contrast images

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Seon Young; Kim, Yoo Kyung; Cho, Hyun Hae; Choi, Mi Joo; Shim, Sung Shine; Lee, Jeong Kyong; Baek, Seung Yon [School of Medicine, Ewha Womans University, Seou (Korea, Republic of)

    2013-06-15

    To evaluate the reliability of virtual non-contrast (VNC) images reconstructed from contrast-enhanced, dual-energy scans compared with true non-contrast (TNC) images in the assessment of high CT attenuation or calcification of mediastinal lymph nodes. A total of 112 mediastinal nodes from 45 patients who underwent non-contrast and dual-energy contrast-enhanced scans were analyzed. Node attenuation in TNC and VNC images was compared both objectively, using computed tomography (CT) attenuation, and subjectively, via visual scoring (0, attenuation ≤ the aorta; 1, > the aorta; 2, calcification). The relationship among attenuation difference between TNC and VNC images, CT attenuation in TNC images, and net contrast enhancement (NCE) was analyzed. CT attenuation in TNC and VNC images showed moderate agreement (intraclass correlation coefficient, 0.612). The mean absolute difference was 7.8 ± 7.6 Hounsfield unit (HU) (range, 0-36 HU), and the absolute difference was equal to or less than 10 HU in 65.2% of cases (73/112). Visual scores in TNC and VNC images showed fair agreement (κ value, 0.335). Five of 16 nodes (31.3%) which showed score 1 (n = 15) or 2 (n = 1) in TNC images demonstrated score 1 in VNC images. The TNC-VNC attenuation difference showed a moderate positive correlation with CT attenuation in TNC images (partial correlation coefficient [PCC] adjusted by NCE: 0.455) and a weak negative correlation with NCE (PCC adjusted by CT attenuation in TNC: -0.245). VNC images may be useful in the evaluation of mediastinal lymph nodes by providing additional information of high CT attenuation of nodes, although it is underestimated compared with TNC images.

  16. Simultaneous all-optical digital comparator and dual-directional half-subtractor for two-input 40 Gbit/s DPSK signals employing SOAs

    Science.gov (United States)

    Zhang, Yin; Lei, Lei; Dong, Jianji; Zhang, Xinliang

    2012-02-01

    A module of simultaneous implementation of all-optical digital comparator and dual-directional half-subtractor is proposed. Proof-of-concept experiment is performed at 40 Gbit/s employing the four-wave mixing and cross gain modulation in three parallel semiconductor optical amplifiers. All output results with over 10 dB extinction ratios, clear and wide open eye diagrams, are obtained without using assistant/holding light beam. All-optical half-adder can also be obtained by adjusting the phase shifter of delay interferometer in the proposed module because of its inherent reconfigurability and flexibility. The module would be a promising digital logic elementary circuit in all-optical networks and computing systems.

  17. Dual-Input Soft-Switched DC-DC Converter with Isolated Current-Fed Half-Bridge and Voltage-Fed Full-Bridge for Fuel Cell or Photovoltaic Systems

    DEFF Research Database (Denmark)

    Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.

    2013-01-01

    This paper introduces a new zero-voltage-switching (ZVS) isolated DC-DC converter with two input ports which can be utilized in hybrid energy systems, for instance, in a fuel cell and super-capacitor system. By fully using two high frequency transformers, the proposed converter can effectively...

  18. Performance of geothermal power plants (single, dual, and binary) to compensate for LHC-CERN power consumption: comparative study

    National Research Council Canada - National Science Library

    El Haj Assad, M; Bani-Hani, E; Khalil, M

    2017-01-01

    .... Results show that the binary power plant has the best performance and lowest cost compared with other geothermal power plants analyzed, and there is a reduction in the total power generation cost...

  19. Macular Hole Surgery with Internal Limiting Membrane Peeling Facilitated by Membrane-Blue® versus Membrane-Blue-Dual®: A Retrospective Comparative Study

    Science.gov (United States)

    Shai, Daniel; Loewenstein, Anat

    2016-01-01

    Background. This study aims to compare the outcome of macular hole (MH) surgery with internal limiting membrane (ILM) peeling facilitated by two different vital dyes. Methods. This was a retrospective chart review. The group designated “group-MB” underwent pars plana vitrectomy with ILM peeling facilitated by Membrane-Blue (MB), whereas in “group-MBD,” the vital dye used was Membrane-Blue-Dual (MBD). Results. Seventy-four eyes comprised the study population: 53 in group-MB and 21 in group-MBD. There was no difference in the rate of macular hole closure in group-MB or group-MBD: 71.2% closed MHs compared to 66.7%, respectively (p = 0.7). Postoperative visual improvement was of a higher magnitude in the MBD group compared to the MB group: −0.34 ± 0.81 logMAR versus 0.01 ± 0.06 logMAR, respectively (p = 0.003). Conclusions. In this study, MBD led to better visual results that may be related to better staining characteristics or lesser toxicity compared to MB. PMID:28050275

  20. Non invasive assessment of renal artery using dual MRA techniques compared with invasive renal angiography in cases of renovascular hypertension

    Directory of Open Access Journals (Sweden)

    Y. Ragab

    2011-03-01

    Conclusion: The combined approach of non-invasive CE MRA and PC MRA techniques achieves a very high specificity, PPV and NPV for the detection of renal arterial pathomorphologic features as compared to standard renal angiography. Adding PC MRA to CE MRA helps to differentiate between mild and moderate stenoses as well as moderate and sever arterial stenotic lesions. So, CE MRA is a morphological test while PC MRA helps in grading the arterial stenoses.

  1. Voltage-gated Proton Channels

    Science.gov (United States)

    DeCoursey, Thomas E.

    2014-01-01

    Voltage-gated proton channels, HV1, have vaulted from the realm of the esoteric into the forefront of a central question facing ion channel biophysicists, namely the mechanism by which voltage-dependent gating occurs. This transformation is the result of several factors. Identification of the gene in 2006 revealed that proton channels are homologues of the voltage-sensing domain of most other voltage-gated ion channels. Unique, or at least eccentric, properties of proton channels include dimeric architecture with dual conduction pathways, perfect proton selectivity, a single-channel conductance ~103 smaller than most ion channels, voltage-dependent gating that is strongly modulated by the pH gradient, ΔpH, and potent inhibition by Zn2+ (in many species) but an absence of other potent inhibitors. The recent identification of HV1 in three unicellular marine plankton species has dramatically expanded the phylogenetic family tree. Interest in proton channels in their own right has increased as important physiological roles have been identified in many cells. Proton channels trigger the bioluminescent flash of dinoflagellates, facilitate calcification by coccolithophores, regulate pH-dependent processes in eggs and sperm during fertilization, secrete acid to control the pH of airway fluids, facilitate histamine secretion by basophils, and play a signaling role in facilitating B-cell receptor mediated responses in B lymphocytes. The most elaborate and best-established functions occur in phagocytes, where proton channels optimize the activity of NADPH oxidase, an important producer of reactive oxygen species. Proton efflux mediated by HV1 balances the charge translocated across the membrane by electrons through NADPH oxidase, minimizes changes in cytoplasmic and phagosomal pH, limits osmotic swelling of the phagosome, and provides substrate H+ for the production of H2O2 and HOCl, reactive oxygen species crucial to killing pathogens. PMID:23798303

  2. Dual energy CT

    DEFF Research Database (Denmark)

    Al-Najami, Issam; Drue, Henrik Christian; Steele, Robert

    2017-01-01

    and inaccurate with existing methods. Dual Energy Computed Tomography (DECT) enables qualitative tissue differentiation by simultaneous scanning with different levels of energy. We aimed to assess the feasibility of DECT in quantifying tumor response to neoadjuvant therapy in loco-advanced rectal cancer. METHODS...... to determine the average quantitative parameters; effective-Z, water- and iodine-concentration, Dual Energy Index (DEI), and Dual Energy Ratio (DER). These parameters were compared to the regression in the resection specimen as measured by the pathologist. RESULTS: Changes in the quantitative parameters...

  3. Myocardial perfusion imaging with dual energy CT.

    Science.gov (United States)

    Jin, Kwang Nam; De Cecco, Carlo N; Caruso, Damiano; Tesche, Christian; Spandorfer, Adam; Varga-Szemes, Akos; Schoepf, U Joseph

    2016-10-01

    Dual-energy CT (DECT) enables simultaneous use of two different tube voltages, thus different x-ray absorption characteristics are acquired in the same anatomic location with two different X-ray spectra. The various DECT techniques allow material decomposition and mapping of the iodine distribution within the myocardium. Static dual-energy myocardial perfusion imaging (sCTMPI) using pharmacological stress agents demonstrate myocardial ischemia by single snapshot images of myocardial iodine distribution. sCTMPI gives incremental values to coronary artery stenosis detected on coronary CT angiography (CCTA) by showing consequent reversible or fixed myocardial perfusion defects. The comprehensive acquisition of CCTA and sCTMPI offers extensive morphological and functional evaluation of coronary artery disease. Recent studies have revealed that dual-energy sCTMPI shows promising diagnostic accuracy for the detection of hemodynamically significant coronary artery disease compared to single-photon emission computed tomography, invasive coronary angiography, and cardiac MRI. The aim of this review is to present currently available DECT techniques for static myocardial perfusion imaging and recent clinical applications and ongoing investigations.

  4. Modelling of the dual frequency capacitive sheath in the intermediate pressure range

    Energy Technology Data Exchange (ETDEWEB)

    Boyle, P C [Plasma Research Laboratory, National Centre for Plasma Science and Technology and School of Physical Sciences, Dublin City University, Dublin 9 (Ireland); Robiche, J [Laboratoire de Physique et Technologie des Plasmas, Ecole Polytechnique, Palaiseau 91 128 Cedex (France); Turner, M M [Plasma Research Laboratory, National Centre for Plasma Science and Technology and School of Physical Sciences, Dublin City University, Dublin 9 (Ireland)

    2004-05-21

    The nonlinearity of the plasma sheath in dual frequency capacitively coupled reactors is investigated for frequencies well above the ion plasma frequency. This work focuses on the behaviour of the voltage and the sheath width with respect to the driving current source and the collisionality regime. For typical plasma processing applications, the gas pressure ranges from a few milliTorrs to hundreds of milliTorrs, and the ion dynamics span different collisional regimes. To describe these different ion dynamics, we have used a collisionless model and a variable mobility model. The sheath widths and the voltages obtained from these two models have then been compared.

  5. Comparing Three Dual-Task Methods and the Relationship to Physical and Cognitive Impairment in People with Multiple Sclerosis and Controls

    Directory of Open Access Journals (Sweden)

    Megan C. Kirkland

    2015-01-01

    Full Text Available Dual-tasking (DT is a measure to detect impairments in people with multiple sclerosis (MS. We compared three DT methods to determine whether cognitive (Montreal Cognitive Assessment (MoCA or physical disability (Expanded Disease Severity Scale; EDSS was related to DT performance. We recruited MS participants with low disability (<3 EDSS, n=13 and high disability (≥3 EDSS, n=9 and matched controls (n=13. Participants walked at self-selected (SS speed on an instrumented walkway (Protokinetics, Havertown, USA, followed by DT walks in randomized order: DT ABC (reciting every second letter of the alphabet, DT 7 (serially subtracting 7’s from 100, and DT 3 (counting upwards, leaving out multiples and numbers that include 3. DT 7 resulted in the most consistent changes in performance. Both MS and control groups reduced velocity and cadence and shortened step length during DT with no significant differences between groups. Control subjects widened stride width by about 1 cm while MS subjects (collapsed as one group did not. MS subjects with higher disability significantly increased percentage time in double support during DT compared to SS (F=12.95, p<0.001. The change in DS was related to cognitive and not physical disability (r=0.54,  p<0.05.

  6. Transient Voltage Recorder

    Science.gov (United States)

    Medelius, Pedro J. (Inventor); Simpson, Howard J. (Inventor)

    2002-01-01

    A voltage transient recorder can detect lightning induced transient voltages. The recorder detects a lightning induced transient voltage and adjusts input amplifiers to accurately record transient voltage magnitudes. The recorder stores voltage data from numerous monitored channels, or devices. The data is time stamped and can be output in real time, or stored for later retrieval. The transient recorder, in one embodiment, includes an analog-to-digital converter and a voltage threshold detector. When an input voltage exceeds a pre-determined voltage threshold, the recorder stores the incoming voltage magnitude and time of arrival. The recorder also determines if its input amplifier circuits clip the incoming signal or if the incoming signal is too low. If the input data is clipped or too low, the recorder adjusts the gain of the amplifier circuits to accurately acquire subsequent components of the lightning induced transients.

  7. Dual-hemisphere tDCS facilitates greater improvements for healthy subjects' non-dominant hand compared to uni-hemisphere stimulation

    Directory of Open Access Journals (Sweden)

    Cerruti Carlo

    2008-10-01

    Full Text Available Abstract Background Transcranial direct current stimulation (tDCS is a non-invasive technique that has been found to modulate the excitability of neurons in the brain. The polarity of the current applied to the scalp determines the effects of tDCS on the underlying tissue: anodal tDCS increases excitability, whereas cathodal tDCS decreases excitability. Research has shown that applying anodal tDCS to the non-dominant motor cortex can improve motor performance for the non-dominant hand, presumably by means of changes in synaptic plasticity between neurons. Our previous studies also suggest that applying cathodal tDCS over the dominant motor cortex can improve performance for the non-dominant hand; this effect may result from modulating inhibitory projections (interhemispheric inhibition between the motor cortices of the two hemispheres. We hypothesized that stimultaneously applying cathodal tDCS over the dominant motor cortex and anodal tDCS over the non-dominant motor cortex would have a greater effect on finger sequence performance for the non-dominant hand, compared to stimulating only the non-dominant motor cortex. Sixteen right-handed participants underwent three stimulation conditions: 1 dual-hemisphere – with anodal tDCS over the non-dominant motor cortex, and cathodal tDCS over the dominant motor cortex, 2 uni-hemisphere – with anodal tDCS over the non-dominant motor cortex, and 3 sham tDCS. Participants performed a finger-sequencing task with the non-dominant hand before and after each stimulation. The dependent variable was the percentage of change in performance, comparing pre- and post-tDCS scores. Results A repeated measures ANOVA yielded a significant effect of tDCS condition (F(2,30 = 4.468, p = .037. Post-hoc analyses revealed that dual-hemisphere stimulation improved performance significantly more than both uni-hemisphere (p = .021 and sham stimulation (p = .041. Conclusion We propose that simultaneously applying cathodal t

  8. Comparative study of regulated and unregulated air pollutant emissions before and after conversion of automobiles from gasoline power to liquefied petroleum gas/gasoline dual-fuel retrofits.

    Science.gov (United States)

    Yang, Hsi-Hsien; Chien, Shu-Mei; Cheng, Man-Ting; Peng, Chiung-Yu

    2007-12-15

    Liquefied petroleum gas (LPG) is increasingly being examined as an alternative to gasoline use in automobiles as interest grows in reducing air pollutant emissions. In this study, emissions of regulated (CO, THC, NO(x)) and unregulated air pollutants, including CO2, particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), and BTEX (acronym for benzene, toluene, ethylbenzene, xylene), were measured before and after conversion of nine gasoline-powered automobiles to LPG/ gasoline dual-fuel retrofits. The tests were conducted on a standard chassis dynamometer in accordance with the United States Environmental Protection Agency FTP-75 test procedure, with the exception that all tests were conducted under hot-start driving conditions. The influences of LPG on air pollutant emission levels and carcinogenic potency were investigated and compared with gasoline. The results showed average emission factors of 0.14 g/km, 0.33 mg/km, 0.09 g/km, 0.44 g/km, and 197 g/km for CO, THC, NO(x), PM, and CO2, respectively, for LPG/ gasoline dual-fuel retrofits. Paired-sample t-test results indicated that the emissions of CO (p = 0.03), THC (p = 0.04), and CO2 (p = 4.6 x 10(-8)) were significantly reduced with the retrofit in comparison with gasoline-powered automobiles. The reduction percentages were 71%, 89%, and 14% for CO, THC, and CO2, respectively. The average total PAH emission factor for LPG was 217 microg/km, which is significantly lower than gasoline (863 microg/km; p = 0.05). The PAH corresponding carcinogenicities (BaP(eq)) were calculated via toxic equivalencies based on benzo(a)pyrene (BaP). Paired-sample t-test results fortotal BaP(eq) emissions showed no significant difference between gasoline (30.0 microg/km) and LPG (24.8 microg/km) at a confidence level of 95%. The discrepancy between PAH and BaP(eq) emissions resulted from the higher emission percentages of high molecular weight PAHs for LPG, which might be from lubricant oil. The average emission factors of

  9. Modelling and Analysis of Dual-Stator Induction Motors

    Science.gov (United States)

    Razik, Hubert; Rezzoug, Abderrezak; Hadiouche, Djafar

    In this paper, the analysis and the modelling of a Dual-Stator Induction Motor (DSIM) are presented. In particular, the effects of the shift angle between its three-phase windings are studied. A complex steady state model is first established in order to analyse its harmonic behavior when it is supplied by a non-sinusoidal voltage source. Then, a new transformation matrix is proposed to develop a suitable dynamic model. In both cases, the study is made using an arbitrary shift angle. Simulation results of its PWM control are also presented and compared in order to confirm our theoretical observations.

  10. Mixed voltage VLSI design

    Science.gov (United States)

    Panwar, Ramesh; Rennels, David; Alkalaj, Leon

    1993-01-01

    A technique for minimizing the power dissipated in a Very Large Scale Integration (VLSI) chip by lowering the operating voltage without any significant penalty in the chip throughput even though low voltage operation results in slower circuits. Since the overall throughput of a VLSI chip depends on the speed of the critical path(s) in the chip, it may be possible to sustain the throughput rates attained at higher voltages by operating the circuits in the critical path(s) with a high voltage while operating the other circuits with a lower voltage to minimize the power dissipation. The interface between the gates which operate at different voltages is crucial for low power dissipation since the interface may possibly have high static current dissipation thus negating the gains of the low voltage operation. The design of a voltage level translator which does the interface between the low voltage and high voltage circuits without any significant static dissipation is presented. Then, the results of the mixed voltage design using a greedy algorithm on three chips for various operating voltages are presented.

  11. Comparative Evaluation of Sloppy Molecular Beacon and Dual-Labeled Probe Melting Temperature Assays to Identify Mutations in Mycobacterium tuberculosis Resulting in Rifampin, Fluoroquinolone and Aminoglycoside Resistance

    Science.gov (United States)

    Lee, Jong Seok; Via, Laura E.; Barry, Clifton E.; Alland, David; Chakravorty, Soumitesh

    2015-01-01

    Several molecular assays to detect resistance to Rifampin, the Fluoroquinolones, and Aminoglycosides in Mycobacterium tuberculosis (M. tuberculosis) have been recently described. A systematic approach for comparing these assays in the laboratory is needed in order to determine the relative advantage of each assay and to decide which ones should be advanced to evaluation. We performed an analytic comparison of a Sloppy Molecular Beacon (SMB) melting temperature (Tm) assay and a Dual labeled probe (DLP) Tm assay. Both assays targeted the M. tuberculosis rpoB, gyrA, rrs genes and the eis promoter region. The sensitivity and specificity to detect mutations, analytic limit of detection (LOD) and the detection of heteroresistance were tested using a panel of 56 clinical DNA samples from drug resistant M. tuberculosis strains. Both SMB and DLP assays detected 29/29 (100%) samples with rpoB RRDR mutations and 3/3 (100%) samples with eis promoter mutations correctly. The SMB assay detected all 17/17 gyrA mutants and 22/22 rrs mutants, while the DLP assay detected 16/17 (94%) gyrA mutants and 12/22 (55%) rrs mutants. Both assays showed comparable LODs for detecting rpoB and eis mutations; however, the SMB assay LODs were at least two logs better for detecting wild type and mutants in gyrA and rrs targets. The SMB assay was also moderately better at detecting heteroresistance. In summary, both assays appeared to be promising methods to detect drug resistance associated mutations in M. tuberculosis; however, the relative advantage of each assay varied under each test condition. PMID:25938476

  12. Comparative Evaluation of Sloppy Molecular Beacon and Dual-Labeled Probe Melting Temperature Assays to Identify Mutations in Mycobacterium tuberculosis Resulting in Rifampin, Fluoroquinolone and Aminoglycoside Resistance.

    Directory of Open Access Journals (Sweden)

    Sandy S Roh

    Full Text Available Several molecular assays to detect resistance to Rifampin, the Fluoroquinolones, and Aminoglycosides in Mycobacterium tuberculosis (M. tuberculosis have been recently described. A systematic approach for comparing these assays in the laboratory is needed in order to determine the relative advantage of each assay and to decide which ones should be advanced to evaluation. We performed an analytic comparison of a Sloppy Molecular Beacon (SMB melting temperature (Tm assay and a Dual labeled probe (DLP Tm assay. Both assays targeted the M. tuberculosis rpoB, gyrA, rrs genes and the eis promoter region. The sensitivity and specificity to detect mutations, analytic limit of detection (LOD and the detection of heteroresistance were tested using a panel of 56 clinical DNA samples from drug resistant M. tuberculosis strains. Both SMB and DLP assays detected 29/29 (100% samples with rpoB RRDR mutations and 3/3 (100% samples with eis promoter mutations correctly. The SMB assay detected all 17/17 gyrA mutants and 22/22 rrs mutants, while the DLP assay detected 16/17 (94% gyrA mutants and 12/22 (55% rrs mutants. Both assays showed comparable LODs for detecting rpoB and eis mutations; however, the SMB assay LODs were at least two logs better for detecting wild type and mutants in gyrA and rrs targets. The SMB assay was also moderately better at detecting heteroresistance. In summary, both assays appeared to be promising methods to detect drug resistance associated mutations in M. tuberculosis; however, the relative advantage of each assay varied under each test condition.

  13. Optical comparator uses holographic subtraction

    Science.gov (United States)

    Vahey, D. W.; Verber, C. M.

    1980-01-01

    Integrated optical comparator compares reference and signal voltages by their effects on coherent light beam. If both voltages are same, beam is essentially unperturbed. If voltages differ, light is deflected by previously recorded hologram to detector.

  14. Comparative study on the clinical and virological characteristics among patients with single occult hepatitis B virus (HBV), single occult hepatitis C virus (HCV) and occult HBV and HCV dual infection.

    Science.gov (United States)

    Castillo, Inmaculada; Rodríguez-Iñigo, Elena; López-Alcorocho, Juan Manuel; Bartolomé, Javier; Pardo, Margarita; Carreño, Vicente

    2007-03-01

    Occult hepatitis B virus (HBV) and occult hepatitis C virus (HCV) infection are two recently described different forms of HBV and HCV infections. This work compares the clinical, virologic, and histologic characteristics of patients with occult dual infection to those of patients with single occult HBV or HCV infection. Seventy-six patients with abnormal liver function tests of unknown etiology (serum HBsAg, anti-HCV, HBV-DNA, and HCV-RNA negative) were included in the study. Viral genomes were tested in liver by real-time PCR and confirmed by in situ hybridization. Of the 76 patients, 17 had occult HBV infection (intrahepatic HBV-DNA positive, HCV-RNA negative), 35 had occult HCV infection (intrahepatic HCV-RNA positive, HBV-DNA negative) and 24 occult dual infection (intrahepatic HCV-RNA and HBV-DNA). No differences among the three groups were found regarding clinical and epidemiologic data. The median load of intrahepatic genomic and antigenomic HCV-RNA strands was similar between single occult HCV infection and occult HBV and HCV dual infection. The percentage of HCV-infected hepatocytes did not differ between these groups. In occult single HBV infection, intrahepatic levels of HBV-DNA and percentage of HBV-infected hepatocytes were similar to the group of patients with occult dual infection. Finally, no differences were found in histological liver damage among the three groups. In conclusion, liver disease in patients with occult dual infection was not more severe than in patients with single occult HBV or occult HCV infection. Moreover, in occult dual infection there is no a reciprocal inhibition of the viral genomes.

  15. Comparison of Algorithms for Control of Loads for Voltage Regulation

    DEFF Research Database (Denmark)

    Douglass, Philip James; Han, Xue; You, Shi

    2014-01-01

    Autonomous flexible loads can be utilized to regulate voltag e on low voltage feeders. This paper compares two algorithms for controllin g loads: a simple voltage droop, where load power consumption is a varied in proportio n to RMS voltage; and a normalized relative voltage droop, which modifies...... the simpl e voltage droop by subtracting the mean voltage value at the bus and dividing by the standard deviation. These two controllers are applied to hot water heaters simul ated in a simple residential feeder. The simulation results show that both controllers r educe the frequency of undervoltage events...

  16. 两级并联单相电压源整流器的无源性控制%Passivity Control over Dual-interleaved Single-phase Voltage Source Rectifier

    Institute of Scientific and Technical Information of China (English)

    马红星; 李华武; 杨喜军

    2013-01-01

    单相电压源整流器(VSR)是一种四象限的AC-DC变换器,可以应用于单相有源电力滤波器和固态变压器.为了提高功率等级,需要采用多个单相VSR输入并联和输出并联的工作方式,为此需要解决各级单相VSR之间的均流问题.提出了一种基于无源性控制的均流方案,首先在理论上证明了单级和两级单相VSR均为无源性系统,且可以产生良好的均流效果.在此基础上,采用MATLAB/SIMULINK进行了仿真验证.结果表明,在功率电路主要参数不一致的情况下,采用无源性控制、交错控制的两级并联单相VSR具有良好的均流效果,网侧功率因数接近于1,输出直流电压幅值可调,并且允许多级单相VSR并联.%Single-phase voltage source rectifier (VSR) is a four-quadrant AC/DC converter,which can be used in many applications,such as single-phase active power filter and solid state transformer.In order to achieve much higher output power,it is applicable to employ parallel cornections both at its input side and output side.However,it is required to solve the issue of current sharing among the different single-phase VSRs.Considering the above referred,a current sharing method based on passivity theory was proposed.At first,what proved was that single-stage VSR and two-stage single-phase VSR were characteristic of passivity-based system theoretically,which could bring about easy current sharing.Then the above theoretical analysis was simulated and verified by means of MATLAB/SIMULINK.The results show that passivity-based control and interleaving control can achieve current sharing even in case of inconsistent parameters,and the power factor at grid side approaches one and DC output voltage can be regulated.Thus it is allowed that more single-stage VSRs are connected in parallel both at input side and output side without current sharing problem.

  17. Analysis of Digital Voltage-Mode Controlled Buck Converter with Dual-Edge Constant on-Time Modulation%双缘COT调制数字电压型控制Buck变换器分析

    Institute of Scientific and Technical Information of China (English)

    周国华; 陈兴; 崔恒丰

    2015-01-01

    为了提高恒定导通时间(constant on-time,COT)调制开关变换器的输出电压稳压精度,基于COT调制和双缘脉冲宽度调制的特点,提出了一种工作于电感电流连续导电模式(continuous conduction mode,CCM)的开关变换器双缘恒定导通时间(dual-edge constant on-time,DCOT)调制方法.介绍了DCOT调制数字电压型控制Buck变换器的工作原理,对比分析了COT调制和DCOT调制数字电压型控制Buck变换器的稳态性能和瞬态性能.结果表明:相比于COT调制,采用DCOT调制的数字电压型控制Buck变换器提高了输出电压的稳压精度,其大小为输出电压纹波峰峰值的50%,且瞬态调节时间减少了1个开关周期.最后,通过仿真和实验结果证明了理论分析的正确性.

  18. Discriminative ability of calcaneal quantitative ultrasound compared with dual-energy X-ray absorptiometry in men with hip or distal forearm fractures.

    Science.gov (United States)

    Cesme, Fatih; Esmaeilzadeh, Sina; Oral, Aydan

    2016-10-01

    The aim of this case-control study was to compare the discriminatory ability of bone mineral density (BMD) measurements and calcaneal quantitative ultrasound (QUS) parameters for fractures and to determine fracture thresholds for each variable in men with hip or distal forearm fractures. A total of 20 men with hip and 18 men with distal forearm fractures and 38 age-matched controls were included in this study. Dual-energy X-ray absorptiometry (DXA) BMD (spine and hip) and calcaneal QUS measurements were made. Area under the curves (AUCs) were calculated to assess fracture discriminatory power of DXA and QUS variables. Quantitative Ultrasound Index (QUI) T-score and Speed of Sound (SOS) were found to be the best parameters for the identification of hip and distal forearm fractures, respectively, with AUCs greater than those of DXA BMD and other QUS parameters. While a QUI T-score of ≤-1.18 could identify and rule out hip fracture cases with approximately 80% sensitivity and specificity, a SOS value of ≤1529.75 reached to almost 90% for ruling in and out distal forearm fractures. The discriminatory performance of calcaneal QUS variables between fractured and non-fractured men was as good as those of the DXA BMD and even better. Since men appear to sustain fractures at closer QUS variable levels than those of the DXA BMD regardless of the fracture type, it may be speculated that calcaneal QUS may be more helpful in predicting the risk of fractures when BMD alone does not demonstrate impaired bones. Level III, Study of Diagnostic Test. Copyright © 2016 Turkish Association of Orthopaedics and Traumatology. Production and hosting by Elsevier B.V. All rights reserved.

  19. A Dual-Bridge LLC Resonant Converter with Fixed-Frequency PWM Control for Wide Input Applications

    DEFF Research Database (Denmark)

    Xiaofeng, Sun; Li, Xiaohua; Shen, Yanfeng;

    2017-01-01

    . Compared with the traditional pulse frequency modulation (PFM) controlled HB/FB LLC resonant converter, the voltage gain range is independent of the quality factor and the magnetizing inductor has little influence on the voltage gain, which can simplify the parameter selection process and benefit...... the design of magnetic components as well. Over the full load range, zero voltage switching (ZVS) and zero current switching (ZCS) can be achieved for primary switches and secondary rectifier diodes, respectively. Detailed analysis on the modulation schedule and operating principle of the proposed converter......This paper proposes a dual-bridge (DB) LLC resonant converter for wide input applications. The topology is an integration of a half-bridge (HB) LLC circuit and a full-bridge (FB) LLC circuit. The fixed-frequency PWM control is employed and a range of twice the minimum input voltage can be covered...

  20. Thoracic applications of dual energy.

    Science.gov (United States)

    Remy-Jardin, Martine; Faivre, Jean-Baptiste; Pontana, Francois; Hachulla, Anne-Lise; Tacelli, Nunzia; Santangelo, Teresa; Remy, Jacques

    2010-01-01

    Recent technological advances in multidetector computed tomography (CT) have led to the introduction of dual-source CT, which allows acquisition of CT data at the same energy or at 2 distinct tube voltage settings during a single acquisition. The advantage of the former is improvement of temporal resolution, whereas the latter offers new options for CT imaging, allowing tissue characterization and functional analysis with morphologic evaluation. The most investigated application has been iodine mapping at pulmonary CT angiography. The material decomposition achievable opens up new options for recognizing substances poorly characterized by single-energy CT. Although it is too early to draw definitive conclusions on dual-energy CT applications, this article reviews the results already reported with the first generation of dual-source CT systems.

  1. Comparative studies on extraction of laminarin by high voltage pulsed electric fields and traditional method%高压脉冲电场和传统热水法提取海带多糖的比较研究

    Institute of Scientific and Technical Information of China (English)

    刘航; 冯立强; 刘兴江

    2016-01-01

    Orthogonal tests are carried out to determine optimal laminarin extraction technologies by the high voltage pulsed electric fields and the traditional hot water method.The mechanism of the high voltage pulsed electric fields is preliminarily discussed.The optimal conditions of traditional method are:1∶50 of material-liquid ratio,60 ℃ of extraction temperature and 40 minutes of extraction time.The optimal conditions of high voltage pulsed electric fields are:1 ∶ 30 of material-liquid ratio,20 minutes of pulse time,10 kV of electric field intensity and 50 Hz of pulse frequency.Compared with traditional hot water extraction method,the extraction time is shortened by 50% and the extraction ratio is increased by 45% for high voltage pulsed electric field method.%利用正交试验确定了高压电脉冲电场和传统热水法提取海带多糖的方法的最佳工艺,并对2种工艺进行了比较,初步探讨高压脉冲的作用机理.结果表明,传统热水法提取海带多糖的最佳工艺为:海带粉与去离子水的料液比为1∶50,提取温度为60℃,提取时间为40 min.高压脉冲电场的最佳工艺为:海带粉与去离子水的料液比为1∶30,脉冲时间为20 min,脉冲电压为10 kV,脉冲频率为50 Hz.提取时间仅为传统热水法时间的1/2,海带多糖提取率比传统热水法提高45%.

  2. Comparing the clinical outcomes in patients with atrial fibrillation receiving dual antiplatelet therapy and patients receiving an addition of an anticoagulant after coronary stent implantation

    Science.gov (United States)

    Chaudhary, Nabin; Bundhun, Pravesh Kumar; Yan, He

    2016-01-01

    Abstract Background: Data regarding the clinical outcomes in patients with atrial fibrillation (AF) receiving dual antiplatelet therapy (DAPT) and an anticoagulant in addition to DAPT (DAPT + vitamin K antagonist [VKA]) after coronary stent implantation are still controversial. Therefore, in order to solve this issue, we aim to compare the adverse clinical outcomes in AF patients receiving DAPT and DAPT + VKA after percutaneous coronary intervention and stenting (PCI-S). Methods: Observational studies comparing the adverse clinical outcomes such as major bleeding, major adverse cardiovascular events, stroke, myocardial infarction, all-cause mortality, and stent thrombosis (ST) in AF patients receiving DAPT + VKA therapy, and DAPT after PCI-S have been searched from Medline, EMBASE, and PubMed databases. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to express the pooled effect on discontinuous variables, and the pooled analyses were performed with RevMan 5.3. Results: Eighteen studies consisting of a total of 20,456 patients with AF (7203 patients received DAPT + VKA and 13,253 patients received DAPT after PCI-S) were included in this meta-analysis. At a mean follow-up period of 15 months, the risk of major bleeding was significantly higher in DAPT + VKA group, with OR 0.62 (95% CI 0.50–0.77, P < 0.0001). There was no significant differences in myocardial infarction and major adverse cardiovascular event between DAPT + VKA and DAPT, with OR 1.27 (95% CI 0.92–1.77, P = 0.15) and OR 1.17 (95% CI 0.99–1.39, P = 0.07), respectively. However, the ST, stroke, and all-cause mortality were significantly lower in the DAPT + VKA group, with OR 1.98 (95% CI 1.03–3.81, P = 0.04), 1.59 (95% CI 1.08–2.34, P = 0.02), and 1.41 (95% CI 1.03–1.94, P = 0.03), respectively. Conclusion: At a mean follow-up period of 15 months, DAPT + VKA was associated with significantly lower risk of stroke, ST, and

  3. Portable High Voltage Impulse Generator

    Directory of Open Access Journals (Sweden)

    S. Gómez

    2011-07-01

    Full Text Available This paper presents a portable high voltage impulse generator which was designed and built with insulation up to 20 kV. This design was based on previous work in which simulation software for standard waves was developed. Commercial components and low-cost components were used in this work; however, these particular elements are not generally used for high voltage applications. The impulse generators used in industry and laboratories are usually expensive; they are built to withstand extra high voltage and they are big, making them impossible to transport. The proposed generator is portable, thereby allowing tests to be made on devices that cannot be moved from their location. The results obtained with the proposed impulse generator were satisfactory in terms of time and waveforms compared to other commercial impulse generators and the standard impulse wave simulator.

  4. Investigating the performance of SiGe embedded dual source p-FinFET architecture

    Science.gov (United States)

    Sinha, Kunal; Gupta, Partha Sarathi; Chattopadhyay, Sanatan; Rahaman, Hafizur

    2016-10-01

    In this work, a modified Fin shaped Field Effect Transistor (FinFET) structure has been proposed with dual SiGe embedded extended source regions. Comparative simulation studies with SiGe embedded source/drain conventional single Fin channel and dual Fin channel FinFET structure having similar device footprint area shows almost 3× and 1.5× improvement of drive current respectively and lower threshold voltage in the proposed architecture. The dual extended SiGe source regions and presence of Si drain in the vertical direction of the channel generate bi-axial channel stress which improves the channel charge density, which results in improvement in drive current significantly. Also it has been observed from various simulation studies that the separated gate regions increase the inversion current density in the channel which also leads to improvement of the device performance.

  5. Preliminary study on ultra low tube voltage (70kV)sequential scan with low-volume contrast media protocol for dual-source CT coronary angiography%70 kV超低管电压低对比剂用量冠状动脉CTA研究

    Institute of Scientific and Technical Information of China (English)

    曹剑; 王少华; 张龙江; 卢光明; 金征宇; 易妍; 王怡宁; 林路; 王明; 孔令燕; 薛华丹; 宋兰; 王志伟

    2014-01-01

    Objective:To investigate the application of ultra low tube voltage (70kV)for coronary artery CT angiog-raphy (CCTA)with low-volume contrast media and low inj ection rate on dual-source CT (DSCT)equipment with integrat-ed circuit (IC)detector.Methods:Fifty patients with body mass index (BMI)not more than 25kg/m2 were scanned with a prospectively ECG-triggering sequential CCTA protocol on DSCT.All patients were randomly divided into two groups:the injection rate and volume of contrast in Group A was 4.0ml/s and 32mL (350mg I/mL);those in Group B were 4.0mL/s and 50mL (350mg I/mL),respectively.Tube voltage of both groups was 70kV.The raw data were reconstructed with sino-gram affirmed iterative reconstruction (SAFIRE)technique.The differences of age,BMI,heart rate,background noise,sig-nal-to-noise ratio (SNR)and radiation dose between the two Groups were compared.Besides,the CT value and CNR of the aortic root and each segment of coronary arteries were compared.And Image quality (1~4,excellent to non-assessable)be-tween the two Groups was compared segment-based.Results:There were no significant differences in age,BMI,heart rate, background noise,SNR or radiation dose between the two Groups (all P>0.05),and the mean ED was about 0.90mSv.The CT value of the distal segment of each coronary arteries in Group B was higher than Group A,while there were no signifi-cant differences in the proximal and median segments between the two groups.However,the CNR of each segment of coro-nary arteries in Group B were higher than Group A (all P<0.01).Mean segment-based image quality scores showed no sig-nificant difference between the two Groups reconstructed with SAFIRE (Group A,1.16±0.18,Group B,1.18±0.18;P=0.75).The percentage of assessable segments in each Group were more than 98%.Conclusion:For patients with normal BMI,the use of tube voltage as 70kV with SAFIRE technique in DSCT equipped IC detector is feasible.And both the con-trast injection rate and volume can be much lower

  6. Dual pathways of calcium entry in spike and plateau phases of luteinizing hormone release from chicken pituitary cells: sequential activation of receptor-operated and voltage-sensitive calcium channels by gonadotropin-releasing hormone

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, J.S.; Wakefield, I.K.; King, J.A.; Mulligan, G.P.; Millar, R.P.

    1988-04-01

    It has previously been shown that, in pituitary gonadotrope cells, the initial rise in cytosolic Ca2+ induced by GnRH is due to a Ca2+ mobilization from intracellular stores. This raises the possibility that the initial transient spike phase of LH release might be fully or partially independent of extracellular Ca2+. We have therefore characterized the extracellular Ca2+ requirements, and the sensitivity to Ca2+ channel blockers, of the spike and plateau phases of secretion separately. In the absence of extracellular Ca2+ the spike and plateau phases were inhibited by 65 +/- 4% and 106 +/- 3%, respectively. Both phases exhibited a similar dependence on concentration of extracellular Ca2+. However, voltage-sensitive Ca2+ channel blockers D600 and nifedipine had a negligible effect on the spike phase, while inhibiting the plateau phase by approximately 50%. In contrast, ruthenium red, Gd3+ ions, and Co2+ ions inhibited both spike and plateau phases to a similar extent as removal of extracellular Ca2+. A fraction (35 +/- 4%) of spike phase release was resistant to removal of extracellular Ca2+. This fraction was abolished after calcium depletion of the cells by preincubation with EGTA in the presence of calcium ionophore A23187, indicating that it depends on intracellular Ca2+ stores. Neither absence of extracellular Ca2+, nor the presence of ruthenium red or Gd3+ prevented mobilization of 45Ca2+ from intracellular stores by GnRH. We conclude that mobilization of intracellular stored Ca2+ is insufficient by itself to account for full spike phase LH release.

  7. Technological Aspects: High Voltage

    CERN Document Server

    Faircloth, D C

    2013-01-01

    This paper covers the theory and technological aspects of high-voltage design for ion sources. Electric field strengths are critical to understanding high-voltage breakdown. The equations governing electric fields and the techniques to solve them are discussed. The fundamental physics of high-voltage breakdown and electrical discharges are outlined. Different types of electrical discharges are catalogued and their behaviour in environments ranging from air to vacuum are detailed. The importance of surfaces is discussed. The principles of designing electrodes and insulators are introduced. The use of high-voltage platforms and their relation to system design are discussed. The use of commercially available high-voltage technology such as connectors, feedthroughs and cables are considered. Different power supply technologies and their procurement are briefly outlined. High-voltage safety, electric shocks and system design rules are covered.

  8. Role of 99mTc-octreotide acetate scintigraphy in suspected lung cancer compared with 18F-FDG dual-head coincidence imaging.

    Science.gov (United States)

    Wang, Feng; Wang, Zizheng; Yao, Weixuan; Xie, Hong; Xu, Jie; Tian, Li

    2007-09-01

    The aim of this study was to evaluate the clinical value of tomographic (99m)Tc-octreotide acetate (hereafter, (99m)Tc-octreotide) scintigraphy in the detection of patients with suspected lung cancer in comparison with that of (18)F-FDG dual-head coincidence imaging (DHC). Forty-four consecutive patients with suspected pulmonary neoplasms underwent tomographic (99m)Tc-octreotide scintigraphy and (18)F-FDG coincidence imaging using the same gantry. The region of interest was drawn on the entire primary lesion. The tumor-to-normal tissue tracer values for both (99m)Tc-octreotide and (18)F-FDG were determined using region of interests and expressed as T/N(r) and T/N(m), respectively. Final diagnosis was confirmed by histopathologic analysis or clinical follow-up. Thirty-one of the 44 patients had lung cancer-6 with small cell lung cancer (SCLC) and 25 with non-small cell lung cancer (NSCLC). Thirteen of the 44 patients had benign lung lesions. The sensitivity, specificity, positive predictive value, and negative predictive value of (99m)Tc-octreotide were 100%, 75.7%, 90.1%, and 100%, respectively, and of (18)F-FDG DHC were 100%, 46.1%, 83.8%, and 100%, respectively. In the 31 patients with malignant tumors, all 38 abnormal lymph nodes in 20 patients showed abnormal high focal uptake of (18)F-FDG; only 7 patients with 10 regional lymph adenopathies showed moderate uptake of (99m)Tc-octreotide. Thirteen patients with 39 distant sites of abnormal uptake visualized (imaging stage IV) with (99m)Tc-octreotide included 2 patients with brain metastases, 6 patients with pleural invasion and multiple bone metastasis, 2 patients with contralateral internal lung metastasis and pleural invasion, and 3 patients with only multiple bone metastasis. The final diagnosis was confirmed by histopathology or clinical follow-up. The sensitivity of (99m)Tc-octreotide for the detection of lung cancer at the primary lesion was comparable with that of (18)F-FDG coincidence imaging. Tomographic

  9. Characterization of liver lesions with mangafodipir trisodium-enhanced MR imaging: multicenter study comparing MR and dual-phase spiral CT

    NARCIS (Netherlands)

    M. Oudkerk (Matthijs); C.G. Torres; B. Song; M. Konig; J. Grimm; J. Fernandez-Cuadrado; B. op de Beeck; M. Marquardt; P. van Dijk (Pieter); J.C. de Groot (Jan Cees)

    2002-01-01

    textabstractPURPOSE: To evaluate whether mangafodipir trisodium (Mn-DPDP)-enhanced magnetic resonance (MR) imaging surpasses dual-phase spiral computed tomography (CT) in differentiating focal liver lesions. MATERIALS AND METHODS: One hundred forty-five patients who had or were sus

  10. Characterization of liver lesions with mangafodipir trisodium-enhanced MR imaging : Multicenter study comparing MR and dual-phase spiral CT

    NARCIS (Netherlands)

    Oudkerk, M; Torres, CG; Song, B; Konig, M; Fernandez-Cuadrado, J; de Beeck, BO; Marquardt, M; van Dijk, P.; de Groot, JC

    2002-01-01

    PURPOSE: To evaluate whether mangafodipir trisodium (Mn-DPDP)- enhanced magnetic resonance (MR) imaging surpasses dual-phase spiral computed tomography (CT) in differentiating focal liver lesions. MATERIALS AND METHODS: One hundred forty-five patients who had or were suspected of having focal liver

  11. Characterization of liver lesions with mangafodipir trisodium-enhanced MR imaging: multicenter study comparing MR and dual-phase spiral CT

    NARCIS (Netherlands)

    M. Oudkerk (Matthijs); C.G. Torres; B. Song; M. Konig; J. Grimm; J. Fernandez-Cuadrado; B. op de Beeck; M. Marquardt; P. van Dijk (Pieter); J.C. de Groot (Jan Cees)

    2002-01-01

    textabstractPURPOSE: To evaluate whether mangafodipir trisodium (Mn-DPDP)-enhanced magnetic resonance (MR) imaging surpasses dual-phase spiral computed tomography (CT) in differentiating focal liver lesions. MATERIALS AND METHODS: One hundred forty-five patients who had or were sus

  12. Characterization of liver lesions with mangafodipir trisodium-enhanced MR imaging : Multicenter study comparing MR and dual-phase spiral CT

    NARCIS (Netherlands)

    Oudkerk, M; Torres, CG; Song, B; Konig, M; Fernandez-Cuadrado, J; de Beeck, BO; Marquardt, M; van Dijk, P.; de Groot, JC

    2002-01-01

    PURPOSE: To evaluate whether mangafodipir trisodium (Mn-DPDP)- enhanced magnetic resonance (MR) imaging surpasses dual-phase spiral computed tomography (CT) in differentiating focal liver lesions. MATERIALS AND METHODS: One hundred forty-five patients who had or were suspected of having focal liver

  13. Stray voltage mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Jamali, B.; Piercy, R.; Dick, P. [Kinetrics Inc., Toronto, ON (Canada). Transmission and Distribution Technologies

    2008-04-09

    This report discussed issues related to farm stray voltage and evaluated mitigation strategies and costs for limiting voltage to farms. A 3-phase, 3-wire system with no neutral ground was used throughout North America before the 1930s. Transformers were connected phase to phase without any electrical connection between the primary and secondary sides of the transformers. Distribution voltage levels were then increased and multi-grounded neutral wires were added. The earth now forms a parallel return path for the neutral current that allows part of the neutral current to flow continuously through the earth. The arrangement is responsible for causing stray voltage. Stray voltage causes uneven milk production, increased incidences of mastitis, and can create a reluctance to drink water amongst cows when stray voltages are present. Off-farm sources of stray voltage include phase unbalances, undersized neutral wire, and high resistance splices on the neutral wire. Mitigation strategies for reducing stray voltage include phase balancing; conversion from single to 3-phase; increasing distribution voltage levels, and changing pole configurations. 22 refs., 5 tabs., 13 figs.

  14. High voltage engineering

    CERN Document Server

    Rizk, Farouk AM

    2014-01-01

    Inspired by a new revival of worldwide interest in extra-high-voltage (EHV) and ultra-high-voltage (UHV) transmission, High Voltage Engineering merges the latest research with the extensive experience of the best in the field to deliver a comprehensive treatment of electrical insulation systems for the next generation of utility engineers and electric power professionals. The book offers extensive coverage of the physical basis of high-voltage engineering, from insulation stress and strength to lightning attachment and protection and beyond. Presenting information critical to the design, selec

  15. High voltage test techniques

    CERN Document Server

    Kind, Dieter

    2001-01-01

    The second edition of High Voltage Test Techniques has been completely revised. The present revision takes into account the latest international developments in High Voltage and Measurement technology, making it an essential reference for engineers in the testing field.High Voltage Technology belongs to the traditional area of Electrical Engineering. However, this is not to say that the area has stood still. New insulating materials, computing methods and voltage levels repeatedly pose new problems or open up methods of solution; electromagnetic compatibility (EMC) or components and systems al

  16. Mitigation of Unbalanced Voltage Sags and Voltage Unbalance in CIGRE Low Voltage Distribution Network

    OpenAIRE

    Mustafa, Ghullam; Bak-Jensen, Birgitte; Mahat, Pukar; Cecati, Carlo

    2013-01-01

    Any problem with voltage in a power network is undesirable as it aggravates the quality of the power. Power electronic devices such as Voltage Source Converter (VSC) based Static Synchronous Compensator (STATCOM) etc. can be used to mitigate the voltage problems in the distribution system. The voltage problems dealt with in this paper are to show how to mitigate unbalanced voltage sags and voltage unbalance in the CIGRE Low Voltage (LV) test network and net-works like this. The voltage unbala...

  17. A Novel Dual-Electrode Plug to Achieve Intensive Electric Field for High Performance Ignition

    Directory of Open Access Journals (Sweden)

    Chih-Lung Shen

    2013-01-01

    Full Text Available A thorough analysis of electric field is carried out so as to verify that a novel dual-electrode plug can build intensive electric field and can improve the main drawbacks of feeble electric field and low ignition efficiency of the traditional plug. With intensive electric field, the proposed novel plug can achieve high performance ignition, resulting in fuel saving and exhaust reduction. Gauss law is applied for electric field analysis to show that intensive electric field can be built by the novel plug. Then, according to Faraday law a lower-voltage ignition feature accomplished by the plug is discussed. Compared with traditional plug, the novel dual-electrode plug has the following advantages. (1 Much higher energy density is built between the plug electrodes, lowering ignition voltage requirement. (2 Electromagnetic interference (EMI problem caused by high ignition voltage is readily resolved. (3 Ignition time delay can be improved. (4 The feature to save fuel consuming is achieved. (5 The exhaust of CO and HC is reduced significantly. Practical measurements are fulfilled to validate the electric field analysis and to demonstrate the features of the proposed dual-electrode plug.

  18. Comparison and Digital Circuit Analysis Based on Low Power Subthreshold Dual Mode Logic

    Directory of Open Access Journals (Sweden)

    D.Naveen Kumar

    2014-03-01

    Full Text Available In this brief, we propose new low power techniques such as Variable body bias method. This technique reduces the leakage power by increasing the body to source voltage of the sleep transistor in the design. By reducing the leakage power overall power of the design is reduced. The proposed logic switches between the active mode and sleep mode. To reduce the leakage current in sleep mode, the body to source voltage of the sleep transistor increased. To increase the voltage of Sleep transistor another transistor is connected to it. Average power and delay are the parameters compared between proposed logic to their CMOS and Dual Mode Logic counter parts in 180-nm process.

  19. Performance evaluation of Type-3 PLLs under wide variation in input voltage and frequency

    DEFF Research Database (Denmark)

    Aravind, C. K.; Rani, B.Indu; Chakkarapani, M.

    2017-01-01

    This paper presents a detailed analysis of Type-3 PLL under wide variation in input voltage and frequency. Using small signal modeling, the performance of both single loop and dual loop type-3 PLL for variation in input voltage and frequency is studied. The analysis shows that for the same...... bandwidth, both the single loop and dual loop Type-3 PLL exhibit similar dynamics provided the supply voltage is balanced. However, under voltage sag conditions, dual loop PLL shows improved dynamic response without affecting its stability. Further, the tracking time is reduced as the feed forward frequency...... is a function of supply frequency. To improve the filtering characteristics under frequency deviations, a dual loop Type 3 adaptive PLL which accurately tracks the phase and frequency of the input signal under wide frequency deviations is developed. Simulations are carried out in MATLAB and experimentally...

  20. Evaluation of the effect of low tube voltage on radiation dose and image quality

    Science.gov (United States)

    Norhasrina Nik Din, Nik; Zainon, Rafidah; Rahman, A. T. Abdul

    2017-05-01

    Number of Computed Tomography (CT) examinations performed worldwide is increasing. In 2010, the FDA issued an initiative to reduce unnecessary radiation exposure from CT imaging. The aim of this study is to evaluate the effect of low tube voltage on radiation dose and image quality using CTDI phantom. The CTDI phantom was scanned with dual energy CT at 80 kV and 120 kV with the tube current from 150 mAs to 350 mAs. Pitch was 1.0 while slice thickness was 1 mm and 5 mm. Results show if mAs was increased, the SNR values also will be increased. The 5 mm slice thickness shows higher SNR value compared to 1 mm slice thickness. As the voltage and tube current increased, the amount of dose absorbed is also increased because current is proportional to photon flux.

  1. Cure of Helicobacter pylori-positive active duodenal ulcer patients: a double-blind, multicentre, 12-month study comparing a two-week dual vs a one-week triple therapy. GISU (Interdisciplinary Group for Ulcer Study).

    Science.gov (United States)

    Di Mario, F; Battaglia, F; Dal Bò, N; Leandro, G; Benedetti, E; Bottona, E; Caroli, A; Costan-Biedo, F; De Bastiani, R; Germanà, B; Andrea Grassi, S; Madia, D; Marcon, V; Marin, R; Monica, F; Olivieri, P; Orzes, N; Pilotto, A; Ronzani, G; Saggioro, A; Tafner, G

    2000-03-01

    To compare a two-week dual therapy to a one-week triple therapy for the healing of duodenal ulcer and the eradication of the Helicobacter pylori infection. A total of 165 patients with active duodenal ulcer were enrolled in the study. At entry, endoscopy, clinical examination and laboratory tests were performed. Histology and the rapid urease test were used to diagnose Helicobacter pylori infection. Patients received either lansoprazole 30 mg plus amoxycillin 1 g bid for two weeks (two-week, dual therapy) or lansoprazole 30 mg plus amoxycillin 1 g plus tinidazole 500 mg bid for one week plus lansoprazole qd for an additional week (one-week, triple therapy). Two and twelve months after cessation of therapy, endoscopy and clinical assessments were repeated. Duodenal ulcer healing and Helicobacter pylori eradication were both significantly greater (p<0.0001) in the triple therapy group (healing: 98.6%; Helicobacter pylori cure rate: 72.6%) than in the dual therapy group (healing: 77.3%; Helicobacter pylori cure rate: 33.3%). Ulcers healed more frequently in Helicobacter pyloricured than in Helicobacter pylori-not cured patients (94.9% vs. 77.2%; p<0.0022). After one year, Helicobacter pylori eradication was re-confirmed in 46/58 patients previously treated with the triple therapy and in 10/40 patients treated with the dual therapy [p<0.0001]. Only three duodenal ulcer relapses were observed throughout follow-up: all were in Helicobacter pylori-not cured patients. Triple therapy was more effective than dual both in curing Helicobacter pylori infection and healing active duodenal ulcers. The speed of ulcer healing obtained after only 7 days of antibiotics and 14 days of proton pump inhibitors confirmed that longer periods of anti ulcer therapy were not necessary. Helicobacter pylori -not cured patients had more slowly healing ulcers which were more apt to relapse when left untreated.

  2. A randomized, double blind, placebo and active comparator controlled pilot study of UP446, a novel dual pathway inhibitor anti-inflammatory agent of botanical origin

    Directory of Open Access Journals (Sweden)

    Sampalis John S

    2012-04-01

    Full Text Available Abstract Background Current use of prescribed or over the counter non-steroidal anti-inflammatory drugs (NSAIDs for pain and osteoarthritis (OA have untoward gastrointestinal and cardiovascular related side effects, as a result the need for a safe and effective alternative has become unequivocally crucial. Method A randomized, double blind, placebo and active controlled pilot study of a novel dual pathway, COX1/2 and LOX, inhibitor anti-inflammatory agent of botanical origin, UP446 was conducted. Sixty subjects (age 40-75 with symptomatic OA of the hip or knee were assigned to 4 treatment groups (n = 15; Group A0 (Placebo, CMC capsule, Group A1 (UP446 250 mg/day, Group A2 (UP446 500 mg/day and Group A3 (Celecoxib, 200 mg/day. MOS-SF-36 and Western Ontario and McMaster University Osteoarthritis Index (WOMAC data were collected at baseline and after 30, 60 and 90 days of treatment as a measure of efficacy. Erythrocyte sedimentation rate, C-reactive protein, plasma thrombin time (PTT, fructosamine, Hematology, clinical chemistry and fecal occult blood were monitored for safety. Results Statistically significant decrease in WOMAC pain score were observed for Group A1 at day 90, Group A2 at 30 and 90 days and Group A3 at 60 and 90 days. Statistically significant decrease in WOMAC stiffness score were observed for Group A1 and Group A2 at 30, 60 and 90 days; but not for Group A0 and Group A3. The mean change in WOMAC functional impairment scores were statistically significant for Group A1 and Group A2 respectively at 30 days (p = 0.006 and p = 0.006, at 60 days (p = 0.016 and p = 0.002 and at 90 days (p = 0.018 and p = 0.002, these changes were not significant for Group A0 and Group A3. Based on MOS -SF-36 questionnaires, statistically significant improvements in physical function, endurance and mental health scores were observed for all active treatment groups compared to placebo. No significant changes suggestive of toxicity in routine hematologies

  3. Study of dual-source CT coronary angiography using low tube voltage setting in patients with low body mass index%低体质量指数患者双源CT低管电压冠状动脉成像的应用研究

    Institute of Scientific and Technical Information of China (English)

    曹建新; 王鹏; 王一民; 杨诚; 王帅

    2013-01-01

    Objective To explore the feasibility of dual-source CT coronary angiography (CTCA) using 80 kV tube voltage setting in patients with low body mass index (BMI).Methods A total of 240 patients with suspected coronary artery disease (BMI range 18.6-21.5 kg/m2) underwent dual-source CTCA.They were randomly assigned to group A (120 kV tube voltage),B (100 kV tube voltage) and C (80 kV tube voltage) based on a random number table.The contrast media dose,volume CT dose index (CTDIvol),dose length product (DLP),and effective dose (ED) were evaluated for each patient.Image noise,CT value,contrast,signal-to-noise ratio (SNR),contrast-to-noise ratio (CNR) and figure of merit (FOM) of coronary artery were all evaluated.Tie image quality of coronary artery was assessed with a threepoint scale (3 points:excellent,2 points:general,1 point:poor).Scan length,CTDIvol,DLP,ED,and contrast media dose for patients,image noise,CT value,contrast,SNR,CNR,and FOM of coronary artery were all analyzed using one-way ANOV4 analysis for 3 groups.Time windows of ECG-pulsing protocol were analyzed using x2 test,and the image quality scores of coronary artery were analyzed using Kruskal-Wallis test.Results There were no differences in scan length and Time windows of ECG-pulsing protocol among 3 groups (scan length F =2.58,P > 0.05,Time windows of ECG-pulsing protocol x2 =0.77,P > 0.05).The average contrast media doses were (82.0 ± 6.4),(76.8 ± 6.1),and (59.1 ± 3.5) ml,the average CTDIvol were(27.5 ±6.2),(18.7 ±4.4),and(11.4 ±2.4)mGy,the average DLPs were (427.7 ±92.4),(295.4 ± 77.1),and (183.9 ± 41.3) mGy · cm,and the average EDs were (6.1 ± 1.3),(4.1 ± 1.1),and (2.6 ± 0.6) msy for group A,B and C,respectively.There were statistical differences in contrast media dose,CTDIvoI,DLP,and ED among 3 groups (the F values for contrast media dose,CTDIvol,DLP,and ED were 383.08,248.13,221.05,and 234.81,respectively,all P <0.01).Compared to group A and B,the contrast media dose in group C

  4. Dual diagnosis

    OpenAIRE

    2013-01-01

    Dual diagnosis denotes intertwining of intellectual disabilities with mental disorders. With the help of systematic examination of literature, intellectual disabilities are determined (they are characterized by subaverage intellectual activity and difficulties in adaptive skills), along side mental disorders. Their influence is seen in changes of thinking, perception, emotionality, behaviour and cognition. Mental disorders often occur with people with intellectual disabilities (data differs f...

  5. Voltage verification unit

    Science.gov (United States)

    Martin, Edward J.

    2008-01-15

    A voltage verification unit and method for determining the absence of potentially dangerous potentials within a power supply enclosure without Mode 2 work is disclosed. With this device and method, a qualified worker, following a relatively simple protocol that involves a function test (hot, cold, hot) of the voltage verification unit before Lock Out/Tag Out and, and once the Lock Out/Tag Out is completed, testing or "trying" by simply reading a display on the voltage verification unit can be accomplished without exposure of the operator to the interior of the voltage supply enclosure. According to a preferred embodiment, the voltage verification unit includes test leads to allow diagnostics with other meters, without the necessity of accessing potentially dangerous bus bars or the like.

  6. Model-based seafloor characterization employing multi-beam angular backscatter data - A comparative study with dual-frequency single beam

    Digital Repository Service at National Institute of Oceanography (India)

    Haris, K.; Chakraborty, B.; De, C.; Desai, R.G.P.; Fernandes, W.A.

    backscattering strengths cause frequency dependence that can be exploited in multi-frequency seafloor classification. 12 The aim of this work is to characterize seafloor sediment with three frequencies employing MB and dual-frequency SB systems operable at 95... The shelf sediments also frequently contain shelly material, which have to be sieved prior to the measurement by laser diffraction. The percentage distribution of sediment compositions (based on Shepard’s classification 16 ) shows the presence of four...

  7. New Control Technique Applied in Dynamic Voltage Restorer for Voltage Sag Mitigation

    Directory of Open Access Journals (Sweden)

    Rosli Omar

    2010-01-01

    Full Text Available The Dynamic Voltage Restorer (DVR was a power electronics device that was able to compensate voltage sags on critical loads dynamically. The DVR consists of VSC, injection transformers, passive filters and energy storage (lead acid battery. By injecting an appropriate voltage, the DVR restores a voltage waveform and ensures constant load voltage. There were so many types of the control techniques being used in DVR for mitigating voltage sags. The efficiency of the DVR depends on the efficiency of the control technique involved in switching the inverter. Problem statement: Simulation and experimental investigation toward new algorithms development based on SVPWM. Understanding the nature of DVR and performance comparisons between the various controller technologies available. The proposed controller using space vector modulation techniques obtain higher amplitude modulation indexes if compared with conventional SPWM techniques. Moreover, space vector modulation techniques can be easily implemented using digital processors. Space vector PWM can produce about 15% higher output voltage than standard Sinusoidal PWM. Approach: The purpose of this research was to study the implementation of SVPWM in DVR. The proposed control algorithm was investigated through computer simulation by using PSCAD/EMTDC software. Results: From simulation and experimental results showed the effectiveness and efficiency of the proposed controller based on SVPWM in mitigating voltage sags in low voltage distribution systems. It was concluded that its controller also works well both in balance and unbalance conditions of voltages. Conclusion/Recommendations: The simulation and experimental results of a DVR using PSCAD/EMTDC software based on SVPWM technique showed clearly the performance of the DVR in mitigating voltage sags. The DVR operates without any difficulties to inject the appropriate voltage component to correct rapidly any anomaly in the supply voltage to keep the

  8. ‘A good method of quitting smoking’ or ‘just an alternative to smoking’? Comparative evaluations of e-cigarette and traditional cigarette usage by dual users

    Directory of Open Access Journals (Sweden)

    Tushna Vandrevala

    2017-01-01

    Full Text Available The development of e-cigarettes was initially hailed as a resource in facilitating a reduction in or cessation of cigarette smoking. Many users of e-cigarettes are ‘dual users’, smoking traditional cigarettes and e-cigarettes. The present qualitative study examines the factors that a group of 20 dual users considered to have been influential in their decisions to use e-cigarettes and their comparative evaluations of e-cigarettes and traditional cigarettes. Health concerns were not found to be sole motivators. Participants pointed to financial and contextual considerations, particularly peer influence on uptake and continued usage of e-cigarettes. E-cigarettes were evaluated as comparable to cigarettes in some ways but not in other important respects such as sensation and satisfaction. Different social evaluations of cigarette and e-cigarette usage were discerned which influenced how participants identified as smokers, ‘vapers’ or neither. Findings are discussed in relation to social representations, identity and implications for continued e-cigarette usage among dual users.

  9. Mitigation Voltage Sag in Power System by Static Synchronous Compensator

    Directory of Open Access Journals (Sweden)

    Prechanon Kumkratug

    2010-01-01

    Full Text Available Problem statement: The disturbance in power system is unavoidable situation. It cause in voltage sag in power system. Approach: This study applied the STATCOM to mitigate voltage of the system. The mathematical model of power system equipped with a STATCOM is systematically derived. The presented mathematical model is shown how it effects on voltage sag improvement. The simulation results are tested on a Single Machine Infinite bus. The proposed method is equipped in sample system with severe disturbance. The variation voltage of the system without and with a STATCOM is plotted and compared. Results: It was found that the system without a STATCOM has high voltage variation especially voltage sags whereas with a STATCOM the system voltage has small voltage sages. Conclusion: From the simulation results, the STATCOM can mitigate voltage of power system.

  10. Voltage-gated lipid ion channels

    DEFF Research Database (Denmark)

    Blicher, Andreas; Heimburg, Thomas Rainer

    2013-01-01

    Synthetic lipid membranes can display channel-like ion conduction events even in the absence of proteins. We show here that these events are voltage-gated with a quadratic voltage dependence as expected from electrostatic theory of capacitors. To this end, we recorded channel traces and current...... histograms in patch-experiments on lipid membranes. We derived a theoretical current-voltage relationship for pores in lipid membranes that describes the experimental data very well when assuming an asymmetric membrane. We determined the equilibrium constant between closed and open state and the open...... probability as a function of voltage. The voltage-dependence of the lipid pores is found comparable to that of protein channels. Lifetime distributions of open and closed events indicate that the channel open distribution does not follow exponential statistics but rather power law behavior for long open times...

  11. QCD Dual

    DEFF Research Database (Denmark)

    Sannino, Francesco

    2009-01-01

    We uncover a novel solution of the 't Hooft anomaly matching conditions for QCD. Interestingly in the perturbative regime the new gauge theory, if interpreted as a possible QCD dual, predicts the critical number of flavors above which QCD in the nonperturbative regime, develops an infrared stable...... fixed point. Remarkably this value is identical to the maximum bound predicted in the nonpertubative regime via the all-orders conjectured beta function for nonsupersymmetric gauge theories.......We uncover a novel solution of the 't Hooft anomaly matching conditions for QCD. Interestingly in the perturbative regime the new gauge theory, if interpreted as a possible QCD dual, predicts the critical number of flavors above which QCD in the nonperturbative regime, develops an infrared stable...

  12. Reduced Voltage Scaling in Clock Distribution Networks

    Directory of Open Access Journals (Sweden)

    Khader Mohammad

    2009-01-01

    Full Text Available We propose a novel circuit technique to generate a reduced voltage swing (RVS signals for active power reduction on main buses and clocks. This is achieved without performance degradation, without extra power supply requirement, and with minimum area overhead. The technique stops the discharge path on the net that is swinging low at a certain voltage value. It reduces active power on the target net by as much as 33% compared to traditional full swing signaling. The logic 0 voltage value is programmable through control bits. If desired, the reduced-swing mode can also be disabled. The approach assumes that the logic 0 voltage value is always less than the threshold voltage of the nMOS receivers, which eliminate the need of the low to high voltage translation. The reduced noise margin and the increased leakage on the receiver transistors using this approach have been addressed through the selective usage of multithreshold voltage (MTV devices and the programmability of the low voltage value.

  13. Secondary Voltage Control for Harmonics Suppression in Islanded Microgrids

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Guerrero, Josep M.; Blaabjerg, Frede

    2011-01-01

    This paper proposes a secondary voltage waveform control approach to suppress harmonics in islanded microgrids. Compared with the secondary control for traditional large power systems, the proposed control scheme can regulate the voltage waveform instead of voltage magnitude of sensitive buses in...

  14. COMPARING AND ANALYZING THE SIMILARITIES AND DIFFERENCES BETWEEN CPU HYPER-THREADING AND DUAL-CORE TECHNOLOGIES%比较分析CPU超线程技术与双核技术的异同

    Institute of Scientific and Technical Information of China (English)

    林杰; 余建坤

    2011-01-01

    Hyper-threading and dual-core are two important technologies during the CPU evolution. Hyper-threading technology simulates a physical processor as two "virtual" processors to reduce the idle time of the execution units and some resources, thus increasing CPU utilization. Dual-core technology encapsulates two physical processing cores into one CPU to improve the performance of programs. The paper describes the basic model of CPU, analyzes Hyper-threading and dual-core technology principles, and compares their similarities and differences from three perspectives of system architecture, parallel degree and improved efficiency.%超线程技术和双核技术是CPU发展历程中的重要技术.超线程技术把一个物理处理器模拟成两个“虚拟”的处理器,减少执行单元和一些资源的闲置时间,提高CPU的利用率.双核技术是将两个物理处理核心封装在一个CPU中,提高程序的执行效率.介绍CPU的基本模型,分析超线程和双核的技术原理,并从系统架构、并行程度和提升的效率三个方面比较它们的异同点.

  15. Microvascular obstruction on delayed enhancement cardiac magnetic resonance imaging after acute myocardial infarction, compared with myocardial {sup 201}Tl and {sup 123}I-BMIPP dual SPECT findings

    Energy Technology Data Exchange (ETDEWEB)

    Mori, Hiroaki [Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya (Japan); Department of Cardiology, Kainan Hospital, Yatomi (Japan); Isobe, Satoshi, E-mail: sisobe@med.nagoya-u.ac.jp [Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya (Japan); Sakai, Shinichi [Department of Cardiology, Kainan Hospital, Yatomi (Japan); Yamada, Takashi [Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya (Japan); Watanabe, Naoki; Miura, Manabu [Department of Cardiology, Kainan Hospital, Yatomi (Japan); Uchida, Yasuhiro; Kanashiro, Masaaki; Ichimiya, Satoshi [Department of Cardiology, Yokkaichi Municipal Hospital, Yokkaichi (Japan); Okumura, Takahiro; Murohara, Toyoaki [Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya (Japan)

    2015-08-15

    Highlights: • The percentage infarct size (%IS) was significantly greater in the microvascular obstruction (MO) group than in the non-MO group. • The percentage mismatch score (%MMS) on dual scintigraphy significantly correlated with the %IS and the percentage MO. • The %MMS was significantly greater in the non-MO group than in the MO group, and was an independent predictor for MO. - Abstract: Background: The hypo-enhanced regions within the hyper-enhanced infarct areas detected by cardiac magnetic resonance (CMR) imaging reflect microvascular obstruction (MO) after acute myocardial infarction (AMI). The combined myocardial thallium-201 ({sup 201}Tl)/iodine-123-15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid ({sup 123}I-BMIPP) dual single-photon emission computed tomography (SPECT) is a useful tool for detecting myocardial reversibility after AMI. We evaluated whether MO could be an early predictor of irreversible myocardial damage in comparison with {sup 201}Tl and {sup 123}I-BMIPP dual SPECT findings in AMI patients. Methods: Sixty-two patients with initial AMI who successfully underwent coronary revascularization were enrolled. MO was defined by CMR imaging. Patients were divided into 2 groups as follows: MO group (n = 32) and non-MO group (n = 30). Scintigraphic defect scores were calculated using a 17-segment model with a 5-point scoring system. The mismatch score (MMS) was calculated as follows: the total sum of (Σ) {sup 123}I-BMIPP defect score minus Σ{sup 201}Tl defect score. The percentage mismatch score (%MMS) was calculated as follows: MMS/(Σ{sup 123}I-BMIPP score) × 100 (%). Results: The percentage infarct size (%IS) was significantly greater in the MO group than in the non-MO group (32.2 ± 13.8% vs. 18.3 ± 12.1%, p < 0.001). The %MMS significantly correlated with the %IS and the percentage MO (r = −0.26, p = 0.03; r = −0.45, p < 0.001, respectively). The %MMS was significantly greater in the non-MO group than in the MO group (45.4

  16. High Voltage Distribution

    Science.gov (United States)

    Norbeck, Edwin; Miller, Michael; Onel, Yasar

    2010-11-01

    For detector arrays that require 5 to 10 kV at a few microamps each for hundreds of detectors, using hundreds of HV power supplies is unreasonable. Bundles of hundreds of HV cables take up space that should be filled with detectors. A typical HV module can supply 1 ma, enough current for hundreds of detectors. It is better to use a single HV module and distribute the current as needed. We show a circuit that, for each detector, measures the current, cuts off the voltage if the current exceeds a set maximum, and allows the HV to be turned on or off from a control computer. The entire array requires a single HV cable and 2 or 3 control lines. This design provides the same voltage to all of the detectors, the voltage set by the single HV module. Some additional circuitry would allow a computer controlled voltage drop between the HV and each individual detector.

  17. High voltage engineering fundamentals

    CERN Document Server

    Kuffel, E; Hammond, P

    1984-01-01

    Provides a comprehensive treatment of high voltage engineering fundamentals at the introductory and intermediate levels. It covers: techniques used for generation and measurement of high direct, alternating and surge voltages for general application in industrial testing and selected special examples found in basic research; analytical and numerical calculation of electrostatic fields in simple practical insulation system; basic ionisation and decay processes in gases and breakdown mechanisms of gaseous, liquid and solid dielectrics; partial discharges and modern discharge detectors; and over

  18. Low-voltage gyrotrons

    Science.gov (United States)

    Glyavin, M. Yu.; Zavolskiy, N. A.; Sedov, A. S.; Nusinovich, G. S.

    2013-03-01

    For a long time, the gyrotrons were primarily developed for electron cyclotron heating and current drive of plasmas in controlled fusion reactors where a multi-megawatt, quasi-continuous millimeter-wave power is required. In addition to this important application, there are other applications (and their number increases with time) which do not require a very high power level, but such issues as the ability to operate at low voltages and have compact devices are very important. For example, gyrotrons are of interest for a dynamic nuclear polarization, which improves the sensitivity of the nuclear magnetic resonance spectroscopy. In this paper, some issues important for operation of gyrotrons driven by low-voltage electron beams are analyzed. An emphasis is made on the efficiency of low-voltage gyrotron operation at the fundamental and higher cyclotron harmonics. These efficiencies calculated with the account for ohmic losses were, first, determined in the framework of the generalized gyrotron theory based on the cold-cavity approximation. Then, more accurate, self-consistent calculations for the fundamental and second harmonic low-voltage sub-THz gyrotron designs were carried out. Results of these calculations are presented and discussed. It is shown that operation of the fundamental and second harmonic gyrotrons with noticeable efficiencies is possible even at voltages as low as 5-10 kV. Even the third harmonic gyrotrons can operate at voltages about 15 kV, albeit with rather low efficiency (1%-2% in the submillimeter wavelength region).

  19. Dual-source computed tomography. Effect on regional and global left ventricular function assessment compared to magnetic resonance imaging; Untersuchung der regionalen und globalen linksventrikulaeren Funktion mit der Dual-Source-Computertomografie im Vergleich zur Magnetresonanztomografie

    Energy Technology Data Exchange (ETDEWEB)

    Lueders, F.; Seifarth, H.; Wessling, J.; Heindel, W.; Juergens, Kai Uwe [Inst. fuer Klinische Radiologie, Universitaetsklinikum Muenster (Germany); Fischbach, R. [Klinik fuer Radiologie, Nuklearmedizin und Neuroradiologie, Asklepios Klinik Altona (Germany)

    2009-10-15

    Purpose: to determine regional and global left ventricular (LV) functional parameters and to perform segmental wall thickness (SWT) and motion (WM) analysis of dual source CT (DSCT) with optimized temporal resolution versus MRI. Materials and Methods: 30 patients with known or suspected CAD, non-obstructive HCM, DCM, ARVCM, Fallot Tetralogy, cardiac sarcoidosis and cardiac metastasis underwent DSCT and MRI. The DSCT and MR images were evaluated: end-systolic (ESV), end-diastolic LV (EDV) volumes, stroke volume (SV), ejection fraction (EF), and myocardial mass (MM) as well as LV wall thickening and segmental WM applying the AHA model were obtained and statistically analyzed. Results: The mean LV-EDV (r = 0.96) and ESV (r = 0.98) as well as LV-EF (r = 0.97), SV (r = 0.83), and MM (r = 0.95) correlated well. Bland Altman analysis revealed little systematic underestimation of LV-EF (-1.1 {+-} 7.8%), EDV (-0.3 {+-} 18.2 ml), SV (-1.3 {+-} 16.7 ml) and little overestimation of ESV (1.1 {+-} 7.8 ml) and MM (12.8 {+-} 14.4 g) determined by DSCT. Systolic reconstruction time points correlated well (DSCT 32.2 {+-} 6.7 vs. MRI 35.6 {+-} 4.4% RR-interval). The LV wall thickness obtained by DSCT and MRI showed close correlation in all segments (diameter diff 0.42 {+-} 1 mm). In 413 segments (89%) WM abnormalities were equally rated, whereas DSCT tended to underestimate the degree of wall motion impairment. Conclusion: DSCT with optimized temporal resolution enables regional and global LV function analysis as well as segmental WM analysis in good correlation with MRI. However, the degree of WM impairment is slightly underestimated by DSCT. (orig.)

  20. A Single-inductor Dual-output Buck DC-DC Converter with Adaptive Dead Time Adjustment and Dynamic Voltage Scaling%可实现DVS的单电感双输出降压型直流-直流转换器

    Institute of Scientific and Technical Information of China (English)

    管璐璐; 许伟伟; 李叶; 洪志良

    2013-01-01

    设计了一款单电感双输出(SIDO)的降压型直流-直流转换器,一个输出电压可以进行动态电压转换,在0.725—1.2V直接变化,另一输出电压可实现1.2V和1.8V,两路输出最大可实现500 mA负载电流.转换器根据负载的不同在脉冲宽度调制(PWM)和脉冲频率调制(PFM)之间自动切换.采用死区时间自适应调整的技术来提高系统的转换效率,分段开关则用来降低输出端毛刺.基于TSMC0.25μm CMOS工艺,测试结果证明该系统输出电压纹波低、毛刺小,系统峰值效率可达90%.%A single-inductor dual-output (SIDO) DC-DC converter having one output of 0. 725-1. 2 V with dynamic voltage scaling (DVS) and another output of 1. 2 V/1. 8 V is presented. Both channels can have the maximal load current of 500 mA. The converter can switch between the pulse-frequency modulation (PFM) mode and the pulse-width modulation (PWM) mode automatically according to load condition. Adaptive dead time adjustment is introduced in the system to improve efficiency and the segment driving for the power switches is implemented to reduce spikes. This converter has been fabricated in 0. 25 μn CMOS mixed signal process. The peak conversion efficiency can reach 90%.

  1. Osteitis: a retrospective feasibility study comparing single-source dual-energy CT to MRI in selected patients with suspected acute gout

    Energy Technology Data Exchange (ETDEWEB)

    Diekhoff, Torsten [Humboldt-Universitaet zu Berlin, Freie Universitaet Berlin, Department of Radiology, Charite - Universitaetsmedizin Berlin Campus Mitte, Berlin (Germany); Charite - Universitaetsmedizin Berlin, Department of Radiology (CCM), Berlin (Germany); Scheel, Michael; Hamm, Bernd; Hermann, Kay-Geert A. [Humboldt-Universitaet zu Berlin, Freie Universitaet Berlin, Department of Radiology, Charite - Universitaetsmedizin Berlin Campus Mitte, Berlin (Germany); Hermann, Sandra [Charite - Universitaetsmedizin Berlin Campus Mitte, Department of Rheumatology and Clinical Immunology, Berlin (Germany); Mews, Juergen [Toshiba Medical Systems Europe, BV, Zoetermeer (Netherlands)

    2017-02-15

    Dual-energy computed tomography detects tophi in patients with chronic gout. However, other information that can be obtained from the same scan is not the focus of the current research, e.g., the detection of bone marrow edema (BME) using virtual bone marrow imaging (VBMI). The aim of this study was to evaluate if BME in patients with acute arthritis can be detected with VBMI using magnetic resonance imaging (MRI) as the standard of reference. This retrospective study included 11 patients who underwent both MRI and dual-energy computed tomography (mean interval of 40 days). BME in MRI (standard of reference) and VBMI was judged independently by two different blinded readers. φ-correlation coefficient and Cohen's κ were performed for statistical analysis. Approval was waived by the IRB. Two patients with a final diagnosis of RA and one with septic arthritis showed osteitis on MRI and VBMI. However, in each case, there were individual bones identified with osteitis on MRI but not VBMI. Three additional patients with the final diagnosis of RA were identified correctly as negative for BME. There was a good correlation between both modalities (φ = 0.8; κ = 0.8). Inter-rater reliability was excellent for both modalities (κ = 0.9). We have shown that detecting osteitis using VBMI is feasible in patients with inflammatory arthritis. Further studies are needed on larger, more-targeted populations to better define the indications, accuracy, and added value of this technique. (orig.)

  2. Research on dual current-loop control strategy for grid-connected inverter of directly-driven wind turbine with permanent magnet synchronous generator under unbalanced network voltage conditions%不对称电网电压条件下直驱永磁风力发电机组并网逆变器的双电流闭环控制策略的研究

    Institute of Scientific and Technical Information of China (English)

    程航; 曹五顺; 周明星

    2012-01-01

    在分析不对称电网电压条件下直驱永磁风力发电机组并网逆变器的数学模型和直流母线电压波动机理的基础上,提出了正负序双电流闭环控制策略,并将陷波器应用于传统锁相环控制算法中,完成风力发电机组在电网发生不对称故障下的不脱网运行.在PSCAD/EMTDC环境下建立基于IGBT背靠背变频器的1.5MW永磁直驱风力发电系统仿真模型,仿真结果表明,该系统能够实现最大风能跟踪,并且在电网不对称故障下,该控制策略成功地抑制了直流母线电压的升高,增强不对称电网故障下直驱永磁风力发电系统的不间断运行能力.%According to the performance analysis of the mathematical model of the three-phase grid-connected inverter (GCI) and the fluctuation mechanism on DC voltage of directly-driven wind turbine with permanent magnet synchronous generator (D-PMSG) under unbalanced network voltage conditions, a dual current-loop control strategy (DCC) which oriented on positive and negative voltage and current respectively is proposed to inhibit the DC voltage fluctuation, meanwhile the notch filter is introduced to conventional control strategy of phase-locked loop, so as to complete the wind generator un-off-line operation on grid faults. A 1.5MW D-PMSG with back-to-back IGBT frequency converter is simulated in the PSCAD/EMTDC environment, and simulation results show that the maximum wind energy tracking is achieved in this system and the proposed DCC strategy can prohibit the rise of DC voltage successfully and enhance the ride-through capability of D-PMSG wind generation system under unbalanced network voltage conditions.

  3. Design and Development of Hybrid Multilevel Inverter employing Dual Reference Modulation Technique for Fuel Cell Applications

    Directory of Open Access Journals (Sweden)

    R. Seyezhai

    2011-10-01

    Full Text Available MultiLevel Inverter (MLI has been recognized as an attractive topology for high voltage DC-AC conversion. This paper focuses on a new dual reference modulation technique for a hybrid multilevel inverter employing Silicon carbide (SiC switches for fuel cell applications. The proposed modulation technique employs two reference waveforms and a single inverted sine wave as the carrier waveform. This technique is compared with the conventional dual carrier waveform in terms of output voltage spectral quality and switching losses. An experimental five-level hybrid inverter test rig has been built using SiC switches to implement the proposed algorithm. Gating signals are generated using PIC microcontroller. The performance of the inverter has been analyzed and compared with the result obtained from theory and simulation. Simulation study of Proportional Integral (PI controller for the inverter employing the proposed modulation strategy has been done in MATLAB/SIMULINK. Keywords: Multilevel inverter, SiC , dual reference modulation, switching losses, PI

  4. Piezoelectric Voltage Coupled Reentrant Cavity Resonator

    CERN Document Server

    Carvalho, Natalia C; Floch, Jean-Michel Le; Tobar, Michael Edmund

    2014-01-01

    A piezoelectric voltage coupled microwave reentrant cavity has been developed. The central cavity post is bonded to a piezoelectric actuator allowing the voltage control of small post displacements over a high dynamic range. We show that such a cavity can be implemented as a voltage tunable resonator, a transducer for exciting and measuring mechanical modes of the structure and a transducer for measuring comparative sensitivity of the piezoelectric material. Experiments were conducted at room and cryogenic temperatures with results verified using Finite Element software.

  5. High voltage pulse generator

    Science.gov (United States)

    Fasching, George E.

    1977-03-08

    An improved high-voltage pulse generator has been provided which is especially useful in ultrasonic testing of rock core samples. An N number of capacitors are charged in parallel to V volts and at the proper instance are coupled in series to produce a high-voltage pulse of N times V volts. Rapid switching of the capacitors from the paralleled charging configuration to the series discharging configuration is accomplished by using silicon-controlled rectifiers which are chain self-triggered following the initial triggering of a first one of the rectifiers connected between the first and second of the plurality of charging capacitors. A timing and triggering circuit is provided to properly synchronize triggering pulses to the first SCR at a time when the charging voltage is not being applied to the parallel-connected charging capacitors. Alternate circuits are provided for controlling the application of the charging voltage from a charging circuit to be applied to the parallel capacitors which provides a selection of at least two different intervals in which the charging voltage is turned "off" to allow the SCR's connecting the capacitors in series to turn "off" before recharging begins. The high-voltage pulse-generating circuit including the N capacitors and corresponding SCR's which connect the capacitors in series when triggered "on" further includes diodes and series-connected inductors between the parallel-connected charging capacitors which allow sufficiently fast charging of the capacitors for a high pulse repetition rate and yet allow considerable control of the decay time of the high-voltage pulses from the pulse-generating circuit.

  6. Microvascular obstruction on delayed enhancement cardiac magnetic resonance imaging after acute myocardial infarction, compared with myocardial (201)Tl and (123)I-BMIPP dual SPECT findings.

    Science.gov (United States)

    Mori, Hiroaki; Isobe, Satoshi; Sakai, Shinichi; Yamada, Takashi; Watanabe, Naoki; Miura, Manabu; Uchida, Yasuhiro; Kanashiro, Masaaki; Ichimiya, Satoshi; Okumura, Takahiro; Murohara, Toyoaki

    2015-08-01

    The hypo-enhanced regions within the hyper-enhanced infarct areas detected by cardiac magnetic resonance (CMR) imaging reflect microvascular obstruction (MO) after acute myocardial infarction (AMI). The combined myocardial thallium-201 ((201)Tl)/iodine-123-15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid ((123)I-BMIPP) dual single-photon emission computed tomography (SPECT) is a useful tool for detecting myocardial reversibility after AMI. We evaluated whether MO could be an early predictor of irreversible myocardial damage in comparison with (201)Tl and (123)I-BMIPP dual SPECT findings in AMI patients. Sixty-two patients with initial AMI who successfully underwent coronary revascularization were enrolled. MO was defined by CMR imaging. Patients were divided into 2 groups as follows: MO group (n=32) and non-MO group (n=30). Scintigraphic defect scores were calculated using a 17-segment model with a 5-point scoring system. The mismatch score (MMS) was calculated as follows: the total sum of (Σ) (123)I-BMIPP defect score minus Σ(201)Tl defect score. The percentage mismatch score (%MMS) was calculated as follows: MMS/(Σ(123)I-BMIPP score)×100 (%). The percentage infarct size (%IS) was significantly greater in the MO group than in the non-MO group (32.2±13.8% vs. 18.3±12.1%, p<0.001). The %MMS significantly correlated with the %IS and the percentage MO (r=-0.26, p=0.03; r=-0.45, p<0.001, respectively). The %MMS was significantly greater in the non-MO group than in the MO group (45.4±42.4% vs. 13.3±28.0%, p=0.001), and was an independent predictor for MO (OR 0.97, 95%CI 0.94-0.99, p=0.02). Our results reconfirm that, in comparison with myocardial dual scintigraphy, MO is an important structural abnormality. CMR imaging is useful for the early detection of irreversible myocardial damage after AMI. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  7. Painlevé test for integrability for a combination of Yang’s self-dual equations for (2) gauge fields and Charap's equations for chiral invariant model of pion dynamics and a comparative discussion among the three

    Indian Academy of Sciences (India)

    Susanto Chakraborty; Pranab Krishna Chandra

    2007-04-01

    Painlevé test for integrability for the combined equations generated from Yang's self-dual equations for (2) gauge fields and Charap's equations for chiral invariant model of pion dynamics faces some peculiar situations that allow none of the stages (leading order analysis, resonance calculation and checking of the existence of the requisite number of arbitrary functions) to be conclusive. It is also revealed from a comparative study with the previous results that the existence of abnormal behaviour at any of the stated stages may have a correlation with the existence of chaotic property or some other properties that do not correspond to solitonic behaviour.

  8. An Optimal PR Control Strategy with Load Current Observer for a Three-Phase Voltage Source Inverter

    Directory of Open Access Journals (Sweden)

    Xiaobo Dou

    2015-07-01

    Full Text Available Inverter voltage control is an important task in the operation of a DC/AC microgrid system. To improve the inverter voltage control dynamics, traditional approaches attempt to measure and feedforward the load current, which, however, needs remote measurement with communications in a microgrid system with distributed loads. In this paper, a load current observer (LCO based control strategy, which does not need remote measurement, is proposed for sinusoidal signals tracking control of a three-phase inverter of the microgrid. With LCO, the load current is estimated precisely, acting as the feedforward of the dual-loop control, which can effectively enlarge the stability margin of the control system and improve the dynamic response to load disturbance. Furthermore, multiple PR regulators are applied in this strategy conducted in a stationary  frame to suppress the transient fluctuations and the total harmonic distortion (THD of the output voltage and achieve faster transient performance compared with traditional dual-loop control in a rotating dq0 frame under instantaneous change of various types of load (i.e., balanced load, unbalanced load, and nonlinear load. The parameters of multiple PR regulators are analyzed and selected through the root locus method and the stability of the whole control system is evaluated and analyzed. Finally, the validity of the proposed approach is verified through simulations and a three-phase prototype test system with a TMS320F28335 DSP.

  9. Voltage-dependent gating of hERG potassium channels

    Directory of Open Access Journals (Sweden)

    Yen May eCheng

    2012-05-01

    Full Text Available The mechanisms by which voltage-gated channels sense changes in membrane voltage and energetically couple this with opening of the ion conducting pore has been the source of significant interest. In voltage-gated potassium (Kv channels, much of our knowledge in this area comes from Shaker-type channels, for which voltage-dependent gating is quite rapid. In these channels, activation and deactivation are associated with rapid reconfiguration of the voltage-sensing domain unit that is electromechanically coupled, via the S4-S5 linker helix, to the rate-limiting opening of an intracellular pore gate. However, fast voltage-dependent gating kinetics are not typical of all Kv channels, such as Kv11.1 (human ether-a-go-go related gene, hERG, which activates and deactivates very slowly. Compared to Shaker channels, our understanding of the mechanisms underlying slow hERG gating is much poorer. Here, we present a comparative review of the structure-function relationships underlying voltage-dependent gating in Shaker and hERG channels, with a focus on the roles of the voltage sensing domain and the S4-S5 linker that couples voltage sensor movements to the pore. Measurements of gating current kinetics and fluorimetric analysis of voltage sensor movement are consistent with models suggesting that the hERG activation pathway contains a voltage independent step, which limits voltage sensor transitions. Constraints upon hERG voltage sensor movement may result from loose packing of the S4 helices and additional intra-voltage sensor counter charge interactions. More recent data suggest that key amino acid differences in the hERG voltage sensing unit and S4-S5 linker, relative to fast activating Shaker-type Kv channels, may also contribute to the increased stability of the resting state of the voltage sensor.

  10. Experimental investigation of SDBD plasma actuator driven by AC high voltage with a superimposed positive pulse bias voltage

    Science.gov (United States)

    Qi, Xiao-Hua; Yan, Hui-Jie; Yang, Liang; Hua, Yue; Ren, Chun-Sheng

    2017-08-01

    In this work, a driven voltage consisting of AC high voltage with a superimposed positive pulse bias voltage ("AC+ Positive pulse bias" voltage) is adopted to study the performance of a surface dielectric barrier discharge plasma actuator under atmospheric conditions. To compare the performance of the actuator driven by single-AC voltage and "AC+ Positive pulse bias" voltage, the actuator-induced thrust force and power consumption are measured as a function of the applied AC voltage, and the measured results indicate that the thrust force can be promoted significantly after superimposing the positive pulse bias voltage. The physical mechanism behind the thrust force changes is analyzed by measuring the optical properties, electrical characteristics, and surface potential distribution. Experimental results indicate that the glow-like discharge in the AC voltage half-cycle, next to the cycle where a bias voltage pulse has been applied, is enhanced after applying the positive pulse bias voltage, and this perhaps is the main reason for the thrust force increase. Moreover, surface potential measurement results reveal that the spatial electric field formed by the surface charge accumulation after positive pulse discharge can significantly affect the applied external electric field, and this perhaps can be responsible for the experimental phenomenon that the decrease of thrust force is delayed by pulse bias voltage action after the filament discharge occurs in the glow-like discharge region. The schlieren images further verify that the actuator-induced airflow velocity increases with the positive pulse voltage.

  11. Voltage Regulators for Photovoltaic Systems

    Science.gov (United States)

    Delombard, R.

    1986-01-01

    Two simple circuits developed to provide voltage regulation for highvoltage (i.e., is greater than 75 volts) and low-voltage (i.e., is less than 36 volts) photovoltaic/battery power systems. Use of these circuits results in voltage regulator small, low-cost, and reliable, with very low power dissipation. Simple oscillator circuit controls photovoltaic-array current to regulate system voltage and control battery charging. Circuit senses battery (and system) voltage and adjusts array current to keep battery voltage from exceeding maximum voltage.

  12. Studying Voltage Transformer Ferroresonance

    Directory of Open Access Journals (Sweden)

    Hamid Radmanesh

    2012-09-01

    Full Text Available This study studies the effect of Circuit Breaker Shunt Resistance (CBSR, Metal Oxide Vaistor (MOV and Neutral earth Resistance (NR on the control of ferroresonance in the voltage transformer. It is expected that NR can controlled ferroresonance better than MOV and CBSR. Study has been done on a one phase voltage transformer rated 100 VA, 275 kV. The simulation results reveal that considering the CBSR and MOV exhibits a great mitigating effect on ferroresonance overvoltages, but these resistances cannot control these phenomena for all range of parameters. By applying NR to the system structure, ferroresonance has been controlled and its amplitude has been damped for all parameters values.

  13. Analysis of a Multilevel Dual Active Bridge (ML-DAB DC-DC Converter Using Symmetric Modulation

    Directory of Open Access Journals (Sweden)

    M. A. Moonem

    2015-04-01

    Full Text Available Dual active bridge (DAB converters have been popular in high voltage, low and medium power DC-DC applications, as well as an intermediate high frequency link in solid state transformers. In this paper, a multilevel DAB (ML-DAB has been proposed in which two active bridges produce two-level (2L-5L, 5L-2L and 3L-5L voltage waveforms across the high frequency transformer. The proposed ML-DAB has the advantage of being used in high step-up/down converters, which deal with higher voltages, as compared to conventional two-level DABs. A three-level neutral point diode clamped (NPC topology has been used in the high voltage bridge, which enables the semiconductor switches to be operated within a higher voltage range without the need for cascaded bridges or multiple two-level DAB converters. A symmetric modulation scheme, based on the least number of angular parameters rather than the duty-ratio, has been proposed for a different combination of bridge voltages. This ML-DAB is also suitable for maximum power point tracking (MPPT control in photovoltaic applications. Steady-state analysis of the converter with symmetric phase-shift modulation is presented and verified using simulation and hardware experiments.

  14. Dual-readout Calorimetry

    CERN Document Server

    Akchurin, N; Cardini, A.; Cascella, M.; Cei, F.; De Pedis, D.; Fracchia, S.; Franchino, S.; Fraternali, M.; Gaudio, G.; Genova, P.; Hauptman, J.; La Rotonda, L.; Lee, S.; Livan, M.; Meoni, E.; Moggi, A.; Pinci, D.; Policicchio, A.; Saraiva, J.G.; Sill, A.; Venturelli, T.; Wigmans, R.

    2013-01-01

    The RD52 Project at CERN is a pure instrumentation experiment whose goal is to un- derstand the fundamental limitations to hadronic energy resolution, and other aspects of energy measurement, in high energy calorimeters. We have found that dual-readout calorimetry provides heretofore unprecedented information event-by-event for energy resolution, linearity of response, ease and robustness of calibration, fidelity of data, and particle identification, including energy lost to binding energy in nuclear break-up. We believe that hadronic energy resolutions of {\\sigma}/E $\\approx$ 1 - 2% are within reach for dual-readout calorimeters, enabling for the first time comparable measurement preci- sions on electrons, photons, muons, and quarks (jets). We briefly describe our current progress and near-term future plans. Complete information on all aspects of our work is available at the RD52 website http://highenergy.phys.ttu.edu/dream/.

  15. Dual Double Field Theory

    CERN Document Server

    Bergshoeff, Eric A; Penas, Victor A; Riccioni, Fabio

    2016-01-01

    We present the dual formulation of double field theory at the linearized level. This is a classically equivalent theory describing the duals of the dilaton, the Kalb-Ramond field and the graviton in a T-duality or O(D,D) covariant way. In agreement with previous proposals, the resulting theory encodes fields in mixed Young-tableau representations, combining them into an antisymmetric 4-tensor under O(D,D). In contrast to previous proposals, the theory also requires an antisymmetric 2-tensor and a singlet, which are not all pure gauge. The need for these additional fields is analogous to a similar phenomenon for "exotic" dualizations, and we clarify this by comparing with the dualizations of the component fields. We close with some speculative remarks on the significance of these observations for the full non-linear theory yet to be constructed.

  16. 肱骨远端C型骨折三种双钢板固定方法疗效比较%Comparative study on curative effect of internal fixations with three dual plates for type C fractures of distal humerus

    Institute of Scientific and Technical Information of China (English)

    陶然; 徐华; 王友华; 曹毅; 周振宇; 陆跃; 刘璠

    2013-01-01

    目的 比较肱骨远端C型骨折的三种双钢板固定方法. 方法 选择2004年1月-2008年12月收治的59例肱骨远端C型骨折患者,均采用双钢板固定.其中垂直双钢板固定34例(A组),背侧双钢板固定14例(B组),平行双钢板固定11例(C组).采用Mayo的肘关节评分系统(MEPS)对患侧肘关节进行功能评分.三组围术期的变量用方差分析、x2检验及Fish-er确切概率法进行比较. 结果 平均随访时间28个月(12 ~55个月).所有骨折均顺利愈合,各组疗效均较满意.三组功能结果差异无统计学意义,C组中固定有难度的患者比例明显高于其他两组.A组和B组中常需要1枚额外的髁间螺钉,但在C组中很少需要. 结论 三种双钢板固定均为治疗肱骨远端C型骨折的有效方法,钢板位置的放置常取决于临床骨科医师的经验及骨折的具体形态.%Objective To compare three different internal fixations using dual plates in treatment of type C distal humerus fractures.Methods A total of 59 patients with type C distal humerus fractures fixed with dual plates between January 2004 and December 2008 were enrolled in the study,including 34 patients managed by perpendicular dual plate internal fixation (Group A),14 patients by dorsal dual plate internal fixation (Group B),and 11 patients by parallel dual plate internal fixation (Group C).Functional outcomes of injured elbow joints were assessed using Mayo elbow performance score (MEPS).Fisher' s exact probability,chi-square test and variance analysis were used to compare the perioperative variables among groups.Results The patients were followed up for average 28 months (range,12-55 months),which showed that all fractures were smoothly healed with satisfactory curative effects in each group.There were no significant differences with respect to functional outcomes among three groups.The patients with surgery difficulty in Group C were more than those in other two groups.Besides,an additional

  17. VOLTAGE REGULATORS ASYNCHRONOUS GENERATORS

    Directory of Open Access Journals (Sweden)

    Grigorash O. V.

    2015-06-01

    Full Text Available A promising is currently the use of asynchronous generators with capacitive excitation as a source of electricity in stand-alone power systems. Drive asynchronous generators may exercise as a thermal engine and wind wheel wind power plant or turbines of small hydropower plants. The article discusses the structural and schematics of voltage stabilizers and frequency of asynchronous generators with improved operational and technical specifications. Technical novelty of design solutions of the magnetic system and stabilizers asynchronous generator of electricity parameters confirmed by the patents for the invention of the Russian Federation. The proposed technical solution voltage stabilizer asynchronous generators, can reduce the weight of the block capacitors excitation and reactive power compensation, as well as to simplify the control system power circuit which has less power electronic devices. For wind power plants it is an important issue not only to stabilize the voltage of the generator, but also the frequency of the current. Recommend functionality stabilizer schemes parameters of electric power made for direct frequency converters with artificial and natural switching power electronic devices. It is also proposed as part of stabilization systems use single-phase voltage, three-phase transformers with rotating magnetic field, reduce the level of electromagnetic interference generated by power electronic devices for switching, enhance the efficiency and reliability of the stabilizer.

  18. Geomagnetism and Induced Voltage

    Science.gov (United States)

    Abdul-Razzaq, W.; Biller, R. D.

    2010-01-01

    Introductory physics laboratories have seen an influx of "conceptual integrated science" over time in their classrooms with elements of other sciences such as chemistry, biology, Earth science, and astronomy. We describe a laboratory to introduce this development, as it attracts attention to the voltage induced in the human brain as it…

  19. High-voltage picoamperemeter

    Energy Technology Data Exchange (ETDEWEB)

    Bugl, Andrea; Ball, Markus; Boehmer, Michael; Doerheim, Sverre; Hoenle, Andreas; Konorov, Igor [Technische Universitaet Muenchen, Garching (Germany); Ketzer, Bernhard [Technische Universitaet Muenchen, Garching (Germany); Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany)

    2014-07-01

    Current measurements in the nano- and picoampere region on high voltage are an important tool to understand charge transfer processes in micropattern gas detectors like the Gas Electron Multiplier (GEM). They are currently used to e.g. optimize the field configuration in a multi-GEM stack to be used in the ALICE TPC after the upgrade of the experiment during the 2nd long shutdown of the LHC. Devices which allow measurements down to 1pA at high voltage up to 6 kV have been developed at TU Muenchen. They are based on analog current measurements via the voltage drop over a switchable shunt. A microcontroller collects 128 digital ADC values and calculates their mean and standard deviation. This information is sent with a wireless transmitting unit to a computer and stored in a root file. A nearly unlimited number of devices can be operated simultaneously and read out by a single receiver. The results can also be displayed on a LCD directly at the device. Battery operation and the wireless readout are important to protect the user from any contact to high voltage. The principle of the device is explained, and systematic studies of their properties are shown.

  20. Moving to the RADARSAT Constellation Mission: Comparing Synthesized Compact Polarimetry and Dual Polarimetry Data with Fully Polarimetric RADARSAT-2 Data for Image Classification of Peatlands

    Directory of Open Access Journals (Sweden)

    Lori White

    2017-06-01

    Full Text Available For this research, the Random Forest (RF classifier was used to evaluate the potential of simulated RADARSAT Constellation Mission (RCM data for mapping landcover within peatlands. Alfred Bog, a large peatland complex in Southern Ontario, was used as a test case. The goal of this research was to prepare for the launch of the upcoming RCM by evaluating three simulated RCM polarizations for mapping landcover within peatlands. We examined (1 if a lower RCM noise equivalent sigma zero (NESZ affects classification accuracy, (2 which variables are most important for classification, and (3 whether classification accuracy is affected by the use of simulated RCM data in place of the fully polarimetric RADARSAT-2. Results showed that the two RCM NESZs (−25 dB and −19 dB and three polarizations (compact polarimetry, HH+HV, and VV+VH that were evaluated were all able to achieve acceptable classification accuracies when combined with optical data and a digital elevation model (DEM. Optical variables were consistently ranked to be the most important for mapping landcover within peatlands, but the inclusion of SAR variables did increase overall accuracy, indicating that a multi-sensor approach is preferred. There was no significant difference between the RF classifications which included RADARSAT-2 and simulated RCM data. Both medium- and high-resolution compact polarimetry and dual polarimetric RCM data appear to be suitable for mapping landcover within peatlands when combined with optical data and a DEM.

  1. Myocardial scintigraphy with iodine-123 phenylpentadecanoic acid and thallium-201 in patients with coronary artery disease: A comparative dual-isotope study

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, R.; Rauch, B.; Kapp, M.; Neumann, F.J.; Seitz, F.; Kuebler, W. (Heidelberg Univ. (Germany). Dept. of Cardiology); Bubeck, B. (Heidelberg Univ. (Germany). Dept. of Nuclear Medicine); Mall, G. (Heidelberg Univ. (Germany). Dept. of Pathology); Tillmanns, H. (Giessen Univ. (Germany). Dept. of Cardiology); Stokstad, P.

    1992-11-01

    To characterise the clinical usefulness of serial myocardial scintigraphy with iodine-123 phenylpentadecanoic acid (IPPA) in comparison with thallium-201, dual-isotope investigations were performed in 41 patients with angiographically documented coronary artery disease. Both tracers were adminstered simultaneously during symptom-limited ergometry. Planar scintigrams were acquired immediately after stress, and delayed imaging was performed after 1 h for IPPA and 4 h for {sup 201}Tl. Scintigrams were evaluated both qualitatively and quantitatively using a newly developed algorithm for automated image superposition. Initial myocardial uptake of both tracers was closely correlated (r=0.75, p<0.001). Both tracers also revealed a similar sensitivity for the identification of individual coronary artery stenoses {>=}75% (IPPA: 70%, {sup 201}Tl: 66.3%, P=NS) with identical specificity (69.8%). The number of persistent defects, however, was significantly higher with IPPA (P=0.021), suggesting that visual analysis of serial IPPA scintigrams may overestimate the presence of myocardial scar tissue. On the other hand, previous Q wave myocardial infarction was associated with a decreased regional IPPA clearance (29%{+-}11% vs 44%{+-}11% in normal myocardium, P<0.05). The data indicate that serial myocardial scintigraphy with IPPA is essentially as sensitive as scintigraphy with {sup 201}Tl for the detection of stress-induced perfusion abnormalities. Quantitative analysis of myocardial IPPA kinetics, however, is required for the evaluation of tissue viability. (orig.).

  2. Voltage control in active, intelligent low-voltage distribution networks; Spannungshaltung in aktiven, intelligenten Niederspannungsnetzen

    Energy Technology Data Exchange (ETDEWEB)

    Buelo, Thorsten; Mende, Denis [SMA Solar Technology AG, Niestetal (Germany); Geibel, Dominik [Fraunhofer Institut fuer Windenergie und Energiesystemtechnik (IWES), Kassel (Germany)] [and others

    2012-07-01

    This paper describes approaches for the voltage control in low-voltage distribution networks with a high share of distributed energy resources (DER). Taken into account are devices such as distribution transformers with on-load tap changer (OLTC), photovoltaic-inverters with reactive power capability and electronic voltage controllers (EVC). After a short description regarding voltage control, the devices and selected system concepts as well as the advantages and disadvantages of the different devices are described. Finally, the system-concepts are compared using the example of a real low voltage network, taking into account the possible increase of hosting capacity of the network, curtailing losses and the amount of reactive energy to be provided. (orig.)

  3. Analytical Modeling of Electric Field Distribution in Dual Material Junctionless Surrounding Gate MOSFETs

    Directory of Open Access Journals (Sweden)

    P. Suveetha Dhanaselvam

    2014-10-01

    Full Text Available In this paper, electric field distribution of the junctionless dual material surrounding gate MOSFETs (JLDMSG is developed. Junctionless is a device that has similar characteristics like junction based devices, but junctionless has a positive flatband voltage with zero electric field. In Surrounding gate MOSFETs gate material surrounds the channel in all direction , therefore it can overcome the short channel effects effectively than other devices. In this paper, surface potential and electric field distribution is modelled. The proposed surface potential model is compared with the existing central potential model. It is observed that the short channel effects (SCE is reduced and the performance is better than the existing method.

  4. Towards a Dual Approach

    DEFF Research Database (Denmark)

    Holli, Anne Maria; Harder, Mette Marie Stæhr

    2016-01-01

    countries acknowledged as forerunners in gender equality, which also have ‘fairly strong’ parliamentary standing committees. The results show that both committees on gender equality can be regarded as ‘feminist’ in character and both interact with relevant civil society organisations. Their impact......Drawing on insights from state feminism and legislative studies on parliamentary committees, this article develops a dual approach for the comparative analysis of committees on gender equality. Empirically, it compares the standing committees on gender equality in Denmark and Finland, two Nordic...

  5. The applications of low tube voltage combined with dual-source CT new technology in early childhood chest examination%低管电压结合双源 CT 新技术在幼儿胸部检查中的应用研究

    Institute of Scientific and Technical Information of China (English)

    王宁; 孙建; 冯艳; 董景敏; 司晓静

    2014-01-01

    Objective To explore a more reasonable voltage parameters in early childhood chest examination with dual‐source CT new technology .Methods Selected 150 children product dual‐source CT chest scans which ages 1 to 3 years old ,the tube voltage of 80Kv group ( 50 cases ) ,100Kv group ( 50 cases ) ,120Kv group ( 50 cases ) ,with flash chest scan mode ,using real‐time online mA second adjustment techniques (CARE Dose 4D) and SAFIRE technology for image reconstruction .Two physi‐cians using 5‐point double‐blind method ,evaluated interobserver consistency with Kappa test ,recorded objective noise of ima‐ges ,CT dose index volume (CTDIvol) and dose length product (DLP) .Compared different voltage group subjective image quali‐ty ,objective noise and radiation dose .Results As the tube voltage value increased ,mediastinal and lung windows were improved image quality ,lung window image quality are more than four points ,able to meet the clinical diagnosis requires .Mediastinal win‐dow image score lower than the lung window ,which 80kV mediastinal image quality were less than 3 minutes ,unable to meet the diagnostic needs ,100kV and 120kV mediastinal image able to meet clinical needs .With tube voltage increases The objective noise significantly reduced .CT dose index volume ,dose length product value and the effective dose increases with the voltage in‐creased significantly .The group 80kV and 100kV CT dose index for the group 120kV of 24.2% ,55% .The group 80kV and 100kV effective dose for the group 120kV of 26.9% ,58.1% .Conclusion Chest examination with dual‐source CT in early childhood should be based on clinical needs to choose the right tube voltage .For lung and bronchial lesions ,80kV is able to meet clinical diagnostic needs and significantly reduce radiation measurement ,while for mediastinal lesions ,you need to select a high‐er tube voltage value .%目的:探讨应用双源C T新技术后,在幼儿胸部检查中较为合理

  6. Voltage-gated proton (H(v)1) channels, a singular voltage sensing domain.

    Science.gov (United States)

    Castillo, Karen; Pupo, Amaury; Baez-Nieto, David; Contreras, Gustavo F; Morera, Francisco J; Neely, Alan; Latorre, Ramon; Gonzalez, Carlos

    2015-11-14

    The main role of voltage-gated proton channels (Hv1) is to extrude protons from the intracellular milieu when, mediated by different cellular processes, the H(+) concentration increases. Hv1 are exquisitely selective for protons and their structure is homologous to the voltage sensing domain (VSD) of other voltage-gated ion channels like sodium, potassium, and calcium channels. In clear contrast to the classical voltage-dependent channels, Hv1 lacks a pore domain and thus permeation necessarily occurs through the voltage sensing domain. Hv1 channels are activated by depolarizing voltages, and increases in internal proton concentration. It has been proposed that local conformational changes of the transmembrane segment S4, driven by depolarization, trigger the molecular rearrangements that open Hv1. However, it is still unclear how the electromechanical coupling is achieved between the VSD and the potential pore, allowing the proton flux from the intracellular to the extracellular side. Here we provide a revised view of voltage activation in Hv1 channels, offering a comparative scenario with other voltage sensing channels domains.

  7. Controllable deposition distance of aligned pattern via dual-nozzle near-field electrospinning

    Science.gov (United States)

    Wang, Zhifeng; Chen, Xindu; Zeng, Jun; Liang, Feng; Wu, Peixuan; Wang, Han

    2017-03-01

    For large area micro/nano pattern printing, multi-nozzle electrohydrodynamic (EHD) printing setup is an efficient method to boost productivity in near-field electrospinning (NFES) process. And controlling EHD multi-jet accurate deposition under the interaction of nozzles and other parameters are crucial concerns during the process. The influence and sensitivity of various parameters such as the needle length, needle spacing, electrode-to-collector distance, voltage etc. on the direct-write patterning performance was investigated by orthogonal experiments with dual-nozzle NFES setup, and then the deposition distance estimated based on a novel model was compared with measurement results and proven. More controllable deposition distance and much denser of aligned naofiber can be achieved by rotating the dual-nozzle setup. This study can be greatly contributed to estimate the deposition distance and helpful to guide the multi-nozzle NFES process to accurate direct-write pattern in manufacturing process in future.

  8. Comparing non contrast computerized tomography criteria versus dual X-ray absorptiometry as predictors of radio-opaque upper urinary tract stone fragmentation after electromagnetic shockwave lithotripsy.

    Science.gov (United States)

    Hameed, Diaa A; Elgammal, Mohammed A; ElGanainy, Ehab O; Hageb, Adel; Mohammed, Khaled; El-Taher, Ahmed Mohamed; Mostafa, Mostafa Mohamed; Ahmed, Abdelfatah Ibrahim

    2013-11-01

    The objective of this study was to assess the value of dual X-ray absorptiometry (DXA) in comparison to non contrast computed tomography (NCCT) density as possible predictors of upper urinary tract stone disintegration by shock wave lithotripsy (SWL). This study included 100 consecutive patients, with solitary renal stone 0.5-2 cm or upper ureteral stone up to 1 cm. DXA to calculate stone mineral density (SMD) and stone mineral content (SMC) was done. NCCT was performed to measure Hounsfield units (HU). SWL was performed with an electromagnetic lithotripsy, plain X-ray documented disintegration after SWL. Successful treatment was defined as stone free or complete fragmentation after 1 or 2 sessions of SWL. The impact of patients age, sex, body mass index, stone laterality, location, volume, length, mean SMC and SMD, HU and Hounsfield density (HD), skin to stone distance (SSD) and number of shock waves were evaluated by univariate and multivariate analysis. Only 76 patients were available for follow-up. Success of disintegration was observed in 50 out of 76 patients (65.8 %). On multivariate analysis, SMC and number of shock wave were the significant independent factors affecting SWL outcome (p = 0.04 and p = 0.000, respectively). SMC as detected by DXA is a significant predictor of success of stone disintegration by SWL. SMC measured by DXA is more accurate than HU measured by CT. Patients with high stone mineral content (SMC greater than 0.65 g) should be directly offered another treatment option.

  9. Assess the discrimination of Achilles InSight calcaneus quantitative ultrasound device for osteoporosis in Chinese women: Compared with dual energy X-ray absorptiometry measurements

    Energy Technology Data Exchange (ETDEWEB)

    Jin Ningning, E-mail: ningning_jin@163.com [Department of Obstetrics and Gynecology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100032 (China); Lin Shouqing, E-mail: Shouqing_Lin2003@yahoo.com.cn [Department of Obstetrics and Gynecology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100032 (China); Zhang Ying, E-mail: steel_lee@sina.com.cn [Department of Obstetrics and Gynecology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100032 (China); Chen Fengling, E-mail: bjzqk@126.com [Department of Obstetrics and Gynecology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100032 (China)

    2010-11-15

    Since the implementation of quantitative ultrasound (QUS) technology may become a part of future clinical decision making to identify osteoporosis and prevent fractures, this study was initiated to evaluate the correlations of QUS parameters and axial bone mineral density (BMD) using dual energy X-ray absorptiometry (DXA) and to assess the discrimination of QUS measurements for osteoporosis and osteopenia defined by WHO criteria. 106 native Chinese women (aged 50.2 {+-} 10.9 SD, 21-74 years) were involved. Each subject received both QUS measurements at left calcaneus with Achilles InSight and DXA measurements with DPX-L at lumbar spine (L{sub 2-4}), total hip and femoral neck. Achilles InSight provided the stiffness index (SI) which derived from Broadband Ultrasound Attenuation (BUA) and Speed of Sound (SOS), and the T-scores of SI were calculated. We found that the QUS parameter SI was statistically significant but medium correlated (r = 0.458-0.587) with DXA at the lumbar spine, total hip and femoral neck (P < 0.0001 for all correlations). With ROC analysis, the area under the ROC curve of diagnosis of osteoporosis and osteopenia were 0.933 and 0.796, respectively. To identify osteoporosis, when the T-score threshold of SI was defined as -1.4, the sensitivity was 100%, and the specificity was 73.7%. Our study confirmed that QUS measurements performed with Achilles InSight were capable to identify osteoporosis defined by axial BMD using DXA in Chinese women.

  10. Potassium-Based Dual Ion Battery with Dual-Graphite Electrode.

    Science.gov (United States)

    Fan, Ling; Liu, Qian; Chen, Suhua; Lin, Kairui; Xu, Zhi; Lu, Bingan

    2017-08-01

    A potassium ion battery has potential applications for large scale electric energy storage systems due to the abundance and low cost of potassium resources. Dual graphite batteries, with graphite as both anode and cathode, eliminate the use of transition metal compounds and greatly lower the overall cost. Herein, combining the merits of the potassium ion battery and dual graphite battery, a potassium-based dual ion battery with dual-graphite electrode is developed. It delivers a reversible capacity of 62 mA h g(-1) and medium discharge voltage of ≈3.96 V. The intercalation/deintercalation mechanism of K(+) and PF6(-) into/from graphite is proposed and discussed in detail, with various characterizations to support. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Calculation of buffer batteries with voltage-adding storage batteries

    Energy Technology Data Exchange (ETDEWEB)

    Boldin, R.V.; Koloskov, A.A.; Ratner, G.B.; Sharov, V.N.

    1982-01-01

    A technique is proposed for buffer storage batteries of the NKG type with voltage-adding storage batteries. These batteries (B) guarantee comparatively narrow range of change in the voltage for load with discharge of the storage batteries of the main B to the assigned minimum voltage. The purpose of the calculation is to determine the number of voltage-adding B and the number of storage batteries in each of them. The initial data for calculation are minimum and maximum values of voltage for load and storage batteries of the main B. Expressions have been obtained for determining the depth of the discharge and the final expression for determining the depth of the discharge and the final discharge voltage of the storage batteries of each voltage-adding B. The necessary formulas are presented and the order for making the calculation is given.

  12. Deployment of low-voltage regulator considering existing voltage control in medium-voltage distribution systems

    Directory of Open Access Journals (Sweden)

    Hiroshi Kikusato

    2016-01-01

    Full Text Available Many photovoltaic (PV systems have been installed in distribution systems. This installation complicates the maintenance of all voltages within the appropriate range in all low-voltage distribution systems (LVDSs because the trends in voltage fluctuation differ in each LVDS. The installation of a low-voltage regulator (LVR that can accordingly control the voltage in each LVDS has been studied as a solution to this problem. Voltage control in a medium-voltage distribution system must be considered to study the deployment of LVRs. In this study, we installed LVRs in the LVDSs in which the existing voltage-control scheme cannot prevent voltage deviation and performed a numerical simulation by using a distribution system model with PV to evaluate the deployment of the LVRs.

  13. VKCDB: Voltage-gated potassium channel database

    Directory of Open Access Journals (Sweden)

    Gallin Warren J

    2004-01-01

    Full Text Available Abstract Background The family of voltage-gated potassium channels comprises a functionally diverse group of membrane proteins. They help maintain and regulate the potassium ion-based component of the membrane potential and are thus central to many critical physiological processes. VKCDB (Voltage-gated potassium [K] Channel DataBase is a database of structural and functional data on these channels. It is designed as a resource for research on the molecular basis of voltage-gated potassium channel function. Description Voltage-gated potassium channel sequences were identified by using BLASTP to search GENBANK and SWISSPROT. Annotations for all voltage-gated potassium channels were selectively parsed and integrated into VKCDB. Electrophysiological and pharmacological data for the channels were collected from published journal articles. Transmembrane domain predictions by TMHMM and PHD are included for each VKCDB entry. Multiple sequence alignments of conserved domains of channels of the four Kv families and the KCNQ family are also included. Currently VKCDB contains 346 channel entries. It can be browsed and searched using a set of functionally relevant categories. Protein sequences can also be searched using a local BLAST engine. Conclusions VKCDB is a resource for comparative studies of voltage-gated potassium channels. The methods used to construct VKCDB are general; they can be used to create specialized databases for other protein families. VKCDB is accessible at http://vkcdb.biology.ualberta.ca.

  14. Improving transition voltage spectroscopy of molecular junctions

    Science.gov (United States)

    Markussen, Troels; Chen, Jingzhe; Thygesen, Kristian S.

    2011-04-01

    Transition voltage spectroscopy (TVS) is a promising spectroscopic tool for molecular junctions. The principles in TVS is to find the minimum on a Fowler-Nordheim plot where ln(I/V2) is plotted against 1/V and relate the voltage at the minimum Vmin to the closest molecular level. Importantly, Vmin is approximately half the voltage required to see a peak in the dI/dV curve. Information about the molecular level position can thus be obtained at relatively low voltages. In this work we show that the molecular level position can be determined at even lower voltages, Vmin(α), by finding the minimum of ln(I/Vα) with α<2. On the basis of a simple Lorentzian transmission model we analyze theoretical ab initio as well as experimental I-V curves and show that the voltage required to determine the molecular levels can be reduced by ~30% as compared to conventional TVS. As for conventional TVS, the symmetry/asymmetry of the molecular junction needs to be taken into account in order to gain quantitative information. We show that the degree of asymmetry may be estimated from a plot of Vmin(α) vs α.

  15. Analyzing of Dynamic Voltage Restorer in Series Compensation Voltage

    Directory of Open Access Journals (Sweden)

    Naser Parhizgar

    2012-02-01

    Full Text Available The Dynamic Voltage Restorer (DVR is a series-connected compensator to generate a controllable voltage to against the short-term voltage disturbances. The technique of DVR is an effective and cost competitive approach to improve voltage quality at the load side. This study presents a single-phase and threephase DVR system with reduced switch-count topology to protect the sensitive load against abnormal voltage conditions. Most basic function, the DVR configuration consist of a two level Voltage Source Converter (VSC, a dc energy storage device, a coupling transformer Connected in shunt with the ac system This study presents the application of Dynamic Voltage Restorer (DVR on power distribution systems for mitigation of voltage sag at critical loads. DVR is one of the compensating types of custom power devices. The DVR, which is based on forced-commutated Voltage Source Converter (VSC has been proved suitable for the task of compensating voltage sags/swells. Simulation results are presented to illustrate and understand the performances of DVR in supporting load voltages under voltage sags/swells conditions.

  16. High Voltage Charge Pump

    KAUST Repository

    Emira, Ahmed A.

    2014-10-09

    Various embodiments of a high voltage charge pump are described. One embodiment is a charge pump circuit that comprises a plurality of switching stages each including a clock input, a clock input inverse, a clock output, and a clock output inverse. The circuit further comprises a plurality of pumping capacitors, wherein one or more pumping capacitors are coupled to a corresponding switching stage. The circuit also comprises a maximum selection circuit coupled to a last switching stage among the plurality of switching stages, the maximum selection circuit configured to filter noise on the output clock and the output clock inverse of the last switching stage, the maximum selection circuit further configured to generate a DC output voltage based on the output clock and the output clock inverse of the last switching stage.

  17. Capturing power at higher voltages from arrays of microbial fuel cells without voltage reversal

    KAUST Repository

    Kim, Younggy

    2011-01-01

    Voltages produced by microbial fuel cells (MFCs) cannot be sustainably increased by linking them in series due to voltage reversal, which substantially reduces stack voltages. It was shown here that MFC voltages can be increased with continuous power production using an electronic circuit containing two sets of multiple capacitors that were alternately charged and discharged (every one second). Capacitors were charged in parallel by the MFCs, but linked in series while discharging to the circuit load (resistor). The parallel charging of the capacitors avoided voltage reversal, while discharging the capacitors in series produced up to 2.5 V with four capacitors. There were negligible energy losses in the circuit compared to 20-40% losses typically obtained with MFCs using DC-DC converters to increase voltage. Coulombic efficiencies were 67% when power was generated via four capacitors, compared to only 38% when individual MFCs were operated with a fixed resistance of 250 Ω. The maximum power produced using the capacitors was not adversely affected by variable performance of the MFCs, showing that power generation can be maintained even if individual MFCs perform differently. Longer capacitor charging and discharging cycles of up to 4 min maintained the average power but increased peak power by up to 2.6 times. These results show that capacitors can be used to easily obtain higher voltages from MFCs, allowing for more useful capture of energy from arrays of MFCs. © 2011 The Royal Society of Chemistry.

  18. Increased voltage photovoltaic cell

    Science.gov (United States)

    Ross, B.; Bickler, D. B.; Gallagher, B. D. (Inventor)

    1985-01-01

    A photovoltaic cell, such as a solar cell, is provided which has a higher output voltage than prior cells. The improved cell includes a substrate of doped silicon, a first layer of silicon disposed on the substrate and having opposite doping, and a second layer of silicon carbide disposed on the first layer. The silicon carbide preferably has the same type of doping as the first layer.

  19. High Voltage Seismic Generator

    Science.gov (United States)

    Bogacz, Adrian; Pala, Damian; Knafel, Marcin

    2015-04-01

    This contribution describes the preliminary result of annual cooperation of three student research groups from AGH UST in Krakow, Poland. The aim of this cooperation was to develop and construct a high voltage seismic wave generator. Constructed device uses a high-energy electrical discharge to generate seismic wave in ground. This type of device can be applied in several different methods of seismic measurement, but because of its limited power it is mainly dedicated for engineering geophysics. The source operates on a basic physical principles. The energy is stored in capacitor bank, which is charged by two stage low to high voltage converter. Stored energy is then released in very short time through high voltage thyristor in spark gap. The whole appliance is powered from li-ion battery and controlled by ATmega microcontroller. It is possible to construct larger and more powerful device. In this contribution the structure of device with technical specifications is resented. As a part of the investigation the prototype was built and series of experiments conducted. System parameter was measured, on this basis specification of elements for the final device were chosen. First stage of the project was successful. It was possible to efficiently generate seismic waves with constructed device. Then the field test was conducted. Spark gap wasplaced in shallowborehole(0.5 m) filled with salt water. Geophones were placed on the ground in straight line. The comparison of signal registered with hammer source and sparker source was made. The results of the test measurements are presented and discussed. Analysis of the collected data shows that characteristic of generated seismic signal is very promising, thus confirms possibility of practical application of the new high voltage generator. The biggest advantage of presented device after signal characteristics is its size which is 0.5 x 0.25 x 0.2 m and weight approximately 7 kg. This features with small li-ion battery makes

  20. Dual energy CT: New horizon in medical imaging

    Energy Technology Data Exchange (ETDEWEB)

    Goo, Hyun Woo [Dept. of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Goo, Jin Mo [Dept. of Radiology, Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2017-08-01

    Dual-energy CT has remained underutilized over the past decade probably due to a cumbersome workflow issue and current technical limitations. Clinical radiologists should be made aware of the potential clinical benefits of dual-energy CT over single-energy CT. To accomplish this aim, the basic principle, current acquisition methods with advantages and disadvantages, and various material-specific imaging methods as clinical applications of dual-energy CT should be addressed in detail. Current dual-energy CT acquisition methods include dual tubes with or without beam filtration, rapid voltage switching, dual-layer detector, split filter technique, and sequential scanning. Dual-energy material-specific imaging methods include virtual monoenergetic or monochromatic imaging, effective atomic number map, virtual non-contrast or unenhanced imaging, virtual non-calcium imaging, iodine map, inhaled xenon map, uric acid imaging, automatic bone removal, and lung vessels analysis. In this review, we focus on dual-energy CT imaging including related issues of radiation exposure to patients, scanning and post-processing options, and potential clinical benefits mainly to improve the understanding of clinical radiologists and thus, expand the clinical use of dual-energy CT; in addition, we briefly describe the current technical limitations of dual-energy CT and the current developments of photon-counting detector.

  1. Dual-Energy CT: New Horizon in Medical Imaging.

    Science.gov (United States)

    Goo, Hyun Woo; Goo, Jin Mo

    2017-01-01

    Dual-energy CT has remained underutilized over the past decade probably due to a cumbersome workflow issue and current technical limitations. Clinical radiologists should be made aware of the potential clinical benefits of dual-energy CT over single-energy CT. To accomplish this aim, the basic principle, current acquisition methods with advantages and disadvantages, and various material-specific imaging methods as clinical applications of dual-energy CT should be addressed in detail. Current dual-energy CT acquisition methods include dual tubes with or without beam filtration, rapid voltage switching, dual-layer detector, split filter technique, and sequential scanning. Dual-energy material-specific imaging methods include virtual monoenergetic or monochromatic imaging, effective atomic number map, virtual non-contrast or unenhanced imaging, virtual non-calcium imaging, iodine map, inhaled xenon map, uric acid imaging, automatic bone removal, and lung vessels analysis. In this review, we focus on dual-energy CT imaging including related issues of radiation exposure to patients, scanning and post-processing options, and potential clinical benefits mainly to improve the understanding of clinical radiologists and thus, expand the clinical use of dual-energy CT; in addition, we briefly describe the current technical limitations of dual-energy CT and the current developments of photon-counting detector.

  2. 64-slice coronary computed tomography angiography using low tube voltage of 80 kV in subjects with normal body mass indices: comparative study using 120 kV

    Energy Technology Data Exchange (ETDEWEB)

    Jun, Bo Ram; Yong, Hwan Seok; Kang, Eun-Young; Woo, Ok Hee; Choi, Eun Jung [Department of Radiology, Korea University Guro Hospital, Korea University College of Medicine, Seoul (Korea, Republic of)], E-mail: yhwanseok@naver.com

    2012-12-15

    Background. The radiation dose of coronary computed tomography (CT) angiography (CCTA) is generally higher than that of CT scans of other parts of the body, and there is concern that the high radiation dose may result in increased cancer risk. Although various techniques have recently been introduced to lower the radiation dose of CCTA, there has been no direct comparison between protocols with 80 and 120 kV. Purpose. To assess the image quality and radiation dose of 80-kV electrocardiography (ECG)-gated CCTA in subjects with a normal body mass index (BMI), compared to 120-kV ECG-gated CCTA. Material and Methods. This retrospective study was approved by our local ethics board, and the requirement of written informed consent was waived. We analyzed the CCTA images of 100 subjects with BMIs <25 kg/m2. Fifty subjects underwent 120-kV CCTA, and the other 50 subjects underwent 80-kV CCTA. Two blinded observers independently evaluated the subjective image quality of the coronary arteries. The objective image quality (signal-to-noise ratio [SNR] and contrast-to-noise ratio [CNR]) and radiation dose were also measured in each group. Results. Although the objective image quality of the 80-kV protocol images was significantly poorer than that of 120-kV protocol images (mean SNR, 14.9 {+-} 4.7 vs. 19.8 {+-} 4.4, P < 0.0001; mean CNR, 15.2 {+-} 4.8 vs. 21.6 {+-} 4.7, P < 0.0001), there was no significant difference in the subjective image quality between the two groups (mean image score, 4.7 {+-} 1.1 vs. 4.5 {+-} 0.7 for radiologist 1, P 0.273; 5.0 {+-} 1.0 vs. 4.8 {+-} 1.0 for radiologist 2, P = 0.197). The radiation dose was reduced by 70% with the 80-kV protocol and by 88% with the 80-kV and ECG-based tube current modulation than with the 120-kV protocol (3.42 {+-} 1.16 and 2.9 {+-} 0.8 vs. 11.49 {+-} 3.62 mSv, P < 0.0001). Conclusion. The low tube voltage CCTA protocol using 80 kV allows significant reduction of the radiation dose without impairing the subjective image

  3. Mitigation of Voltage Sags in CIGRE Low Voltage Distribution Network

    DEFF Research Database (Denmark)

    Mustafa, Ghullam; Bak-Jensen, Birgitte; Mahat, Pukar;

    2013-01-01

    problems in the distribution system. The voltage problems dealt with in this paper are to show how to mitigate voltage sags in the CIGRE Low Voltage (LV) test network and networks like this. The voltage sags, for the tested cases in the CIGRE LV test network are mainly due to three phase faults....... The compensation of voltage sags in the different parts of CIGRE distribution network is done by using the four STATCOM compensators already existing in the test grid. The simulations are carried out in DIgSILENT power factory software version 15.0....

  4. Voltage Controlled Dynamic Demand Response

    DEFF Research Database (Denmark)

    Bhattarai, Bishnu Prasad; Bak-Jensen, Birgitte; Mahat, Pukar

    2013-01-01

    . An adaptive dynamic model has been developed to determine composite voltage dependency of an aggregated load on feeder level. Following the demand dispatch or control signal, optimum voltage setting at the LV substation is determined based on the voltage dependency of the load. Furthermore, a new technique...

  5. Charge-pump voltage converter

    Science.gov (United States)

    Brainard, John P.; Christenson, Todd R.

    2009-11-03

    A charge-pump voltage converter for converting a low voltage provided by a low-voltage source to a higher voltage. Charge is inductively generated on a transfer rotor electrode during its transit past an inductor stator electrode and subsequently transferred by the rotating rotor to a collector stator electrode for storage or use. Repetition of the charge transfer process leads to a build-up of voltage on a charge-receiving device. Connection of multiple charge-pump voltage converters in series can generate higher voltages, and connection of multiple charge-pump voltage converters in parallel can generate higher currents. Microelectromechanical (MEMS) embodiments of this invention provide a small and compact high-voltage (several hundred V) voltage source starting with a few-V initial voltage source. The microscale size of many embodiments of this invention make it ideally suited for MEMS- and other micro-applications where integration of the voltage or charge source in a small package is highly desirable.

  6. Comparing the effectiveness and safety between triple antiplatelet therapy and dual antiplatelet therapy in type 2 diabetes mellitus patients after coronary stents implantation: a systematic review and meta-analysis of randomized controlled trials.

    Science.gov (United States)

    Bundhun, Pravesh Kumar; Qin, Tao; Chen, Meng-Hua

    2015-10-09

    Since antiplatelet therapy in type 2 diabetes mellitus (T2DM) patients is very important after intracoronary stenting, and because the most commonly used therapies have been the dual antiplatelet therapy (DAPT) consisting of aspirin and clopidogrel and the triple antiplatelet therapy (TAPT) consisting of aspirin, clopidogrel and cilostazol, we aim to compare the effectiveness and safety between triple antiplatelet therapy and dual antiplatelet therapy in T2DM patients. Systematic literature search was done from the databases of PubMed, Cochrane, Embase, China National Knowledge Infrastructure (CNKI) and WanFang. Randomized controlled trials (RCTs) comparing the effectiveness and safety between triple therapy and dual therapy in T2DM patients after coronary stents placement were included. Endpoints included major adverse cardiac effects (MACEs), target lesion revascularization (TLR), target vessel revascularization (TVR), death, stent thrombosis, bleeding and adverse drug reactions during a 9-12 months period, as well as platelet activities. Four studies including 1005 patients reporting the adverse clinical outcomes and six studies including 519 patients reporting the platelet activities, with a total of 1524 patients have been analyzed in this meta-analysis. The pooling analysis shows that TAPT has significantly decreased the occurrence of MACEs (RR: 0.55; 95 % CI: 0.36-0.86, P = 0.009), TLR (RR 0.41; 95 % CI: 0.21-0.80, P = 0.008), TVR (RR 0.55; 95 % CI: 0.34-0.88, P = 0.01) and the overall incidence of Death/ Myocardial Infarction (MI)/TVR (RR 0.54; 95 % CI: 0.31-0.94, P = 0.03) during this 9 to 12 months follow up period after stents implantation. Stent thrombosis was almost similar in both groups. Bleeding seemed to favor DAPT but the result was not statistically significant. Platelet aggregation, platelet reactivity index (PRI) and platelet reactivity unit (PRU) were also reduced with Weight Mean Difference (WMD) of (-13.80; 95 % CI: -17

  7. Dual cure photocatalyst systems

    Energy Technology Data Exchange (ETDEWEB)

    DeVoe, R.J.; Brown-Wensley, K.A.; Holmes, G.L.; Mathis, M.D.; McCormick, F.B.; Palazzotto, M.C.; Spurgeon, K.M. (Minnesota Mining and Mfg. Co., St. Paul, MN (USA). Corporate Research Labs.)

    1990-01-01

    A family of dual cure photocatalyst systems is being developed to be used in the solventless processing of organic coatings. The photocatalyst systems consist of organometallic compounds often in combination with other agents. Upon photolysis, the photocatalyst system generates a Lewis acid and a free radical. The Lewis acid can initiate the polymerization of epoxies or the addition of isocyanates and polyols to form polyurethanes while the free radical can initiate the polymerization of acrylates. The performance of the various photocatalyst systems will be compared on the basis of the physical properties of the cured compositions they produce. 17 figs.

  8. Transient voltage sharing in series-coupled high voltage switches

    Directory of Open Access Journals (Sweden)

    Editorial Office

    1992-07-01

    Full Text Available For switching voltages in excess of the maximum blocking voltage of a switching element (for example, thyristor, MOSFET or bipolar transistor such elements are often coupled in series - and additional circuitry has to be provided to ensure equal voltage sharing. Between each such series element and system ground there is a certain parasitic capacitance that may draw a significant current during high-speed voltage transients. The "open" switch is modelled as a ladder network. Analy­sis reveals an exponential progression in the distribution of the applied voltage across the elements. Overstressing thus oc­curs in some of the elements at levels of the total voltage that are significantly below the design value. This difficulty is overcome by grading the voltage sharing circuitry, coupled in parallel with each element, in a prescribed manner, as set out here.

  9. A dual cone-beam CT system for image guided radiotherapy: Initial performance characterization

    Energy Technology Data Exchange (ETDEWEB)

    Li Hao; Bowsher, James; Yin Fangfang [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27710 (United States); Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Giles, William [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States)

    2013-02-15

    Purpose: The purpose of this study is to evaluate the performance of a recently developed benchtop dual cone-beam computed tomography (CBCT) system with two orthogonally placed tube/detector sets. Methods: The benchtop dual CBCT system consists of two orthogonally placed 40 Multiplication-Sign 30 cm flat-panel detectors and two conventional x-ray tubes with two individual high-voltage generators sharing the same rotational axis. The x-ray source to detector distance is 150 cm and x-ray source to rotational axis distance is 100 cm for both subsystems. The objects are scanned through 200 Degree-Sign of rotation. The dual CBCT system utilized 110 Degree-Sign of projection data from one detector and 90 Degree-Sign from the other while the two individual single CBCTs utilized 200 Degree-Sign data from each detector. The system performance was characterized in terms of uniformity, contrast, spatial resolution, noise power spectrum, and CT number linearity. The uniformities, within the axial slice and along the longitudinal direction, and noise power spectrum were assessed by scanning a water bucket; the contrast and CT number linearity were measured using the Catphan phantom; and the spatial resolution was evaluated using a tungsten wire phantom. A skull phantom and a ham were also scanned to provide qualitative evaluation of high- and low-contrast resolution. Each measurement was compared between dual and single CBCT systems. Results: Compared to single CBCT, the dual CBCT presented: (1) a decrease in uniformity by 1.9% in axial view and 1.1% in the longitudinal view, as averaged for four energies (80, 100, 125, and 150 kVp); (2) comparable or slightly better contrast (0{approx}25 HU) for low-contrast objects and comparable contrast for high-contrast objects; (3) comparable spatial resolution; (4) comparable CT number linearity with R{sup 2}{>=} 0.99 for all four tested energies; (5) lower noise power spectrum in magnitude. Dual CBCT images of the skull phantom and the

  10. College Course Grades for Dual Enrollment Students

    Science.gov (United States)

    Crouse, Jill D.; Allen, Jeff

    2014-01-01

    This study compared college course grade outcomes, both during and after high school, of dual-enrollment students to those of traditional students. The study was based on a large, multiyear sample of Iowa high school and community college students. The results showed that while in high school, dual-enrollment students consistently outperformed…

  11. Learning from the Past: Dual Credit

    Science.gov (United States)

    Mansell, Nicole; Justice, Madeline

    2014-01-01

    This study involved identifying, categorizing, and comparing critical incidents related to qualifying dual credit high school students' decisions to enroll or not to enroll in dual credit coursework in either a traditional or early college high school. The purpose of the study was (a) to identify the reasons qualifying students decide to enroll in…

  12. Radiation Optimized Dual-source Dual-energy Computed Tomography Pulmonary Angiography: Intra-individual and Inter-individual Comparison.

    Science.gov (United States)

    Li, Xie; Chen, Guo Zhong; Zhao, Yan E; Schoepf, U Joseph; Albrecht, Moritz H; Bickford, Matthew W; Gu, Hai Feng; Zhang, Long Jiang; Lu, Guang Ming

    2017-01-01

    This study aimed to intra-individually and inter-individually compare image quality, radiation dose, and diagnostic accuracy of dual-source dual-energy computed tomography pulmonary angiography (CTPA) protocols in patients with suspected pulmonary embolism (PE). Thirty-three patients with suspected PE underwent initial and follow-up dual-energy CTPA at 80/Sn140 kVp (group A) or 100/Sn140 kVp (group B), which were assigned based on tube voltages. Subjective and objective CTPA image quality and lung perfusion map image quality were evaluated. Diagnostic accuracies of CTPA and perfusion maps were assessed by two radiologists independently. Effective dose (ED) was calculated and compared. Mean computed tomography (CT) values of pulmonary arteries were higher in group A than group B (P = .006). There was no difference in signal-to-noise ratio and contrast-to-noise ratio between the two groups (both P > .05). Interobserver agreement for evaluating subjective image quality of CTPA and color-coded perfusion images was either good (κ = 0.784) or excellent (κ = 0.887). Perfusion defect scores and diagnostic accuracy of CTPA showed no difference between both groups (both P > .05). Effective dose of group A was reduced by 45.8% compared to group B (P energy CTPA with 80/Sn140 kVp allows for sufficient image quality and diagnostic accuracy for detecting PE while substantially reducing radiation dose. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  13. Comparing dynamic recording of infiltration by X-Ray tomography to the results of a dual porosity model for structured soils

    Science.gov (United States)

    Lissy, Anne-Sophie; Sammartino, Stephane; Di Pietro, Liliana; Lecompte, François; Ruy, Stephane

    2017-04-01

    With climate change, preferential flow phenomenon in soil could be predominant in Mediterranean zone. Understanding this phenomenon becomes a fundamental issue for preserving the water resource in quantity (drinking water) and quality (pesticide content). Non-invasive imaging technics, as X-ray tomography, allow studying water infiltration in laboratory with time-lapse imaging to visualize preferential flow path in soil columns (Sammartino et al. 2012). The modeling of water flow with a dual porosity model (matrix and macropores) integrates these fast flow phenomena (Ilhem 2014). These models, however needs more explicit links with the soil structure. The comparison of experimental results of infiltration (dynamics images and mass data) and modeling could improve our comprehension of preferential flow phenomenon and allow a better integration of the functional macroporosity (i.e. which drains water infiltration during a rain event) in such mass transfer models (Sammartino et al. 2015). Soil columns (Ø 12 cm - hauteur 13 cm, clay-loamy & medium sandy loam) have been sampled in the field to preserve their structure (field plowed or not). Several rains have been simulated in the laboratory and the last one was performed in an X-ray medical scanner (Siemens Somatom® 128 slices) at the CIRE platform (INRA, Centre - Val de Loire). Total and functional macro porosities were identified from time lapse tridimensional images. Water dynamics in the porosities was characterized from the identification and analysis of voxels filled by water. With an image resolution of 350μm only water in the largest macropores can be identified. The modeling of these experiments was carried out via the VirtualSoil platform (UMR Emmah, Avignon; www6.inra.fr/vsoil) using a water flow model coupling Darcy-Richards and KDW equations (Di Pietro et al., 2003). The simulated water flux drained by macropores is similar to the experimental hydrograph obtained for rainfalls on soils close to the

  14. A comparative study of inter-abutment distance of dies made from full arch dual-arch impression trays with those made from full arch stock trays: An in vitro study

    Directory of Open Access Journals (Sweden)

    Reddy Jagan

    2009-01-01

    Full Text Available Objectives: The dual-arch impression technique is convenient in that it makes the required maxillary and mandibular impressions, as well as the inter-occlusal record in one procedure. The accuracy of inter-abutment distance in dies fabricated from dual-arch impression technique remains in question because there is little information available in the literature. Materials and Methods: This study was conducted to evaluate the accuracy of inter-abutment distance in dies obtained from full arch dual-arch trays with those obtained from full arch stock metal trays. Results and Conclusion: The metal dual-arch trays showed better accuracy followed by the plastic dual-arch and stock dentulous trays, respectively, though statistically insignificant. The pouring sequence did not have any effect on the inter-abutment distance statistically, though pouring the non-working side of the dual-arch impression first showed better accuracy.

  15. No-Voltage Meter

    Science.gov (United States)

    1976-02-01

    VW- IKft, 1/4 H4 -Wv- IK!1, I/4W INTERNAL VOLTAGE NOTE ALL TRANSISTORS ARE 2N43A OR EQUIVALENT GERMANIUM ALLOY PNP AA ALKALINE BATTERY...D-,, regardless of polarity. This signal is then full-wave rectified by the diode-connected Germanium transistor bridge, T,, T-,, T3, and T4... Transistor T5 acts as a second current limiter. Resistor R2 was selected to give 90 f# of full-scale meter deflection with an input signal of 115 volts

  16. Benchmarking of Voltage Sag Generators

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede; Zou, Zhixiang

    2012-01-01

    The increased penetration of renewable energy systems, like photovoltaic and wind power systems, rises the concern about the power quality and stability of the utility grid. Some regulations for Low Voltage Ride-Through (LVRT) for medium voltage or high voltage applications, are coming into force...... to guide these grid-connected distributed power generation systems. In order to verify the response of such systems for voltage disturbance, mainly for evaluation of voltage sags/dips, a Voltage Sag Generator (VSG) is needed. This paper evaluates such sag test devices according to IEC 61000 in order...... to provide cheaper solutions to test against voltage sags. Simulation and experimental results demonstrate that the shunt impedance based VSG solution is the easiest and cheapest one for laboratory test applications. The back-to-back fully controlled converter based VSG is the most flexible solution...

  17. Investigation of phase-wise voltage regulator control logics for compensating voltage deviations in an experimental low voltage network

    DEFF Research Database (Denmark)

    Hu, Junjie; Zecchino, Antonio; Marinelli, Mattia

    2016-01-01

    either locally or remotely. To evaluate and compare the control performances of the three control logics, all the tests use the same loading profiles. The experimental results indicate that the modified line compensation control can regulate voltage in a safe band in the case of various load......This paper investigates the control logics of an on-load tap-changer (OLTC) transformer by means of an experimental system validation. The experimental low-voltage unbalanced system consists of a decoupled single-phase OLTC transformer, a 75-metre 16 mm2 cable, a controllable single-phase resistive...... load and an electric vehicle, which has the vehicle-to-grid function. Three control logics of the OLTC transformer are described in the study. The three control logics are classified based on their control objectives and control inputs, which include network currents and voltages, and can be measured...

  18. Moderate dietary sodium restriction added to angiotensin converting enzyme inhibition compared with dual blockade in lowering proteinuria and blood pressure : randomised controlled trial

    NARCIS (Netherlands)

    Slagman, Maartje C. J.; Waanders, Femke; Hemmelder, Marc H.; Woittiez, Arend-Jan; Janssen, Wilbert M. T.; Lambers Heerspink, Hiddo J.; Navis, Gerjan; Laverman, Gozewijn D.

    2011-01-01

    Objective To compare the effects on proteinuria and blood pressure of addition of dietary sodium restriction or angiotensin receptor blockade at maximum dose, or their combination, in patients with non-diabetic nephropathy receiving background treatment with angiotensin converting enzyme (ACE) inhib

  19. A prospective study from south India to compare the severity of malaria caused by Plasmodium vivax, P. falciparum and dual infection

    Directory of Open Access Journals (Sweden)

    Shubhanker Mitra

    2015-01-01

    Interpretation & conclusion: This cross-sectional comparative study clearly demonstrates that clinical features, complications and case-fatality rates in vivax malaria can be as severe as in falciparum malaria. Hence, vivax malaria could not be considered benign; and appropriate preventive strategies along with antimalarial therapies should be adopted for control and elimination of this disease.

  20. Moderate dietary sodium restriction added to angiotensin converting enzyme inhibition compared with dual blockade in lowering proteinuria and blood pressure : randomised controlled trial

    NARCIS (Netherlands)

    Slagman, Maartje C. J.; Waanders, Femke; Hemmelder, Marc H.; Woittiez, Arend-Jan; Janssen, Wilbert M. T.; Lambers Heerspink, Hiddo J.; Navis, Gerjan; Laverman, Gozewijn D.

    2011-01-01

    Objective To compare the effects on proteinuria and blood pressure of addition of dietary sodium restriction or angiotensin receptor blockade at maximum dose, or their combination, in patients with non-diabetic nephropathy receiving background treatment with angiotensin converting enzyme (ACE)

  1. The importance of spectral separation: an assessment of dual-energy spectral separation for quantitative ability and dose efficiency.

    Science.gov (United States)

    Krauss, Bernhard; Grant, Katharine L; Schmidt, Bernhard T; Flohr, Thomas G

    2015-02-01

    One method to acquire dual-energy (DE) computed tomography (CT) data is to perform CT scans at 2 different x-ray tube voltages, typically 80 and 140 kV, either as 2 separate scans, by means of rapid kV switching, or with the use of 2 x-ray sources as in dual-source CT (DSCT) systems. In DSCT, it is possible to improve spectral separation with tin prefiltration (Sn) of the high-kV beam. Recently, x-ray tube voltages beyond the established range of 80 to 140 kV were commercially introduced, which enable additional voltage combinations for DE acquisitions, such as 80/150 Sn or 90/150 Sn kV. Here, we investigate the DE performance of several x-ray tube voltages and prefilter combinations on 2 DSCT scanners and the impact of the spectra on quantitative analysis and dose efficiency. Circular phantoms of different sizes (10-40 cm in diameter) equipped with cylindrical inserts containing water and diluted iodine contrast agent (14.5 mg/cm) were scanned using 2 different DSCT systems (SOMATOM Definition Flash and SOMATOM Force; Siemens AG, Forchheim, Germany). Five x-ray tube voltage combinations (80/140 Sn, 100/140 Sn, 80/150 Sn, 90/150 Sn, and 100/150 Sn kV) were investigated, and the results were compared with the previous standard acquisition technique (80/140 kV). As an example, 80/140 Sn kV means that 1 x-ray tube of the DSCT system was operated at 80 kV, whereas the other was operated at 140 kV with additional tin prefiltration (Sn). Dose values in terms of computed tomography dose index (CTDIvol) were kept constant between the different voltage combinations but adjusted with regard to object size according to automatic exposure control recommendations. Reconstructed images were processed using linear blending of the low- and high-kV CT images to combined images, as well as 3-material decomposition techniques to generate virtual noncontrast (VNC) images and iodine images. Contrast and pixel noise were evaluated, as well as DE ratios, which are defined as the CT value

  2. Investigation of dual-energy X-ray photon counting using a cadmium telluride detector with dual-energy selection electronics

    Science.gov (United States)

    Sato, Eiichi; Kosuge, Yoshiyuki; Yamanome, Hayato; Mikata, Akiko; Miura, Tatsuya; Oda, Yasuyuki; Ishii, Tomotaka; Hagiwara, Osahiko; Matsukiyo, Hiroshi; Watanabe, Manabu; Kusachi, Shinya

    2017-01-01

    To obtain two kinds of tomograms at two different X-ray energy ranges simultaneously, we have developed a dual-energy X-ray photon counter with a cadmium telluride (CdTe) detector and two energy-selecting devices (ESDs). The ESD consists of two comparators and a microcomputer (MC). X-ray photons are detected using the CdTe detector, and the event pulses from a shaping amplifier are sent to two ESDs simultaneously to determine two energy ranges. X-ray photons in the two ranges are counted using the MCs, and the logical pulses from the MCs are input to frequency-to-voltage converters (FVCs). The outputs from the two FVCs are input to a personal computer through an analog-to-digital converter to carry out dual-energy computed tomography. The tube voltage and current were 80 kV and 8.5 μA, respectively. Two tomograms were obtained simultaneously with two energy ranges. K-edge CT using iodine and gadolinium media was carried out utilizing two energy ranges of 33-45 and 50-65 keV, respectively. The maximum count rate was 6.8 kilocounts per second with energies ranging from 10 to 80 keV, and the exposure time for tomography was 9.8 min.

  3. Coordinated Voltage Control of Distributed PV Inverters for Voltage Regulation in Low Voltage Distribution Networks

    DEFF Research Database (Denmark)

    Nainar, Karthikeyan; Pokhrel, Basanta Raj; Pillai, Jayakrishnan Radhakrishna

    2017-01-01

    This paper reviews and analyzes the existing voltage control methods of distributed solar PV inverters to improve the voltage regulation and thereby the hosting capacity of a low-voltage distribution network. A novel coordinated voltage control method is proposed based on voltage sensitivity...... analysis, which is simple for computation and requires moderate automation and communication infrastructure. The proposed method is suitable for a hierarchical control structure where a supervisory controller has the provision to adapt the settings of local PV inverter controllers for overall system...

  4. Heat-pump performance: voltage dip/sag, under-voltage and over-voltage

    Directory of Open Access Journals (Sweden)

    William J.B. Heffernan

    2014-12-01

    Full Text Available Reverse cycle air-source heat-pumps are an increasingly significant load in New Zealand and in many other countries. This has raised concern over the impact wide-spread use of heat-pumps may have on the grid. The characteristics of the loads connected to the power system are changing because of heat-pumps. Their performance during under-voltage events such as voltage dips has the potential to compound the event and possibly cause voltage collapse. In this study, results from testing six heat-pumps are presented to assess their performance at various voltages and hence their impact on voltage stability.

  5. Analysis of Possibilities to Reduce the Voltages Induced in Multi-circuit and Multi-voltage Overhead Lines

    Directory of Open Access Journals (Sweden)

    Rafał Tarko

    2015-09-01

    Full Text Available This paper presents the issues of electromagnetic interactions in a four-circuit and dual-voltage power line. Such solutions are increasingly used in practice due to difficulties in land acquisition for the construction of new power lines. Lines of this type, however, have some disadvantages, incl. the electromagnetic interactions between the circuits and voltages induced as their consequence. These issues are considered in relation to an existing four-circuit, 110 kV and 15 kV line. Results of the studies of the interaction effects in a real system, and an analysis of selected ways to reduce the voltage induced in 15 kV line circuits are presented.

  6. Voltage Swells Improvement in Low Voltage Network Using Dynamic Voltage Restorer

    Directory of Open Access Journals (Sweden)

    R. Omar

    2011-01-01

    Full Text Available Problem statement: Voltage disturbances are the most common power quality problem due to the increased use of a large numbers of sophisticated electronic equipment in industrial distribution system. The voltage disturbances such as voltage sags, swells, harmonics, unbalance and flickers. High quality in the power supply is needed, since failures due to such disturbances usually have a high impact on production cost. There are many different solutions to compensate voltage disturbances but the use of a DVR is considered to be the most cost effective method. The objective of this study is to propose a new topology of a DVR in order to mitigate voltage swells using a powerful power custom device namely the Dynamic Voltage Restorer (DVR. Approach: New configuration of a DVR with an improvement of a controller based on direct-quadrature-zero method has been introduced to compensate voltage swells in the network. Results: The effectiveness of the DVR with its controller were verify using Matlab/Simulinks SimPower Toolbox and then implemented using 5KVA DVR experimental setup. Simulations and experimental results demonstrate the effective dynamic performance of the proposed configuration. Conclusion: The implimentation of the proposed DVR validate the capabilities in mitigating of voltage swells effectiveness.During voltage swells, the DVR injects an appropriate voltage to maintain the load voltage at its nominal value.

  7. CNFET Based Voltage Differencing Transconductance Amplifier

    Science.gov (United States)

    Laxya; Prasad, Dinesh; Mainuddin; Islam, S. S.

    2017-08-01

    In CMOS Technology basic Problem mainly includes dopant fluctuation, tunnelling effect and line edge roughness below 45nm technology. Carbon Nanotube based structures is better option for widen the Moore’s law due to its scalability channel electrostatics and higher mobility. In this manuscript we demonstrate an optimum design for linear property of CNTFET based VDTA at 32nm technology node. The proposed circuit consist of VDTA with CNTFET having two voltage input and two current outputs so that it works as voltage and transconductance operation to obtain the high performance. The minimum supply voltages of ±0.9V with 32nm technology mode are used. The CNTFET-VDTA performance is simulated on HSPICE. In this paper CNFET-based VDTA provides better results of DC transfer characteristics as compared with CMOS. All the simulation results are performed on HSPICE.

  8. Isomerically Pure Tetramethylrhodamine Voltage Reporters.

    Science.gov (United States)

    Deal, Parker E; Kulkarni, Rishikesh U; Al-Abdullatif, Sarah H; Miller, Evan W

    2016-07-27

    We present the design, synthesis, and application of a new family of fluorescent voltage indicators based on isomerically pure tetramethylrhodamines. These new Rhodamine Voltage Reporters, or RhoVRs, use photoinduced electron transfer (PeT) as a trigger for voltage sensing, display excitation and emission profiles in the green to orange region of the visible spectrum, demonstrate high sensitivity to membrane potential changes (up to 47% ΔF/F per 100 mV), and employ a tertiary amide derived from sarcosine, which aids in membrane localization and simultaneously simplifies the synthetic route to the voltage sensors. The most sensitive of the RhoVR dyes, RhoVR 1, features a methoxy-substituted diethylaniline donor and phenylenevinylene molecular wire at the 5'-position of the rhodamine aryl ring, exhibits the highest voltage sensitivity to date for red-shifted PeT-based voltage sensors, and is compatible with simultaneous imaging alongside green fluorescent protein-based indicators. The discoveries that sarcosine-based tertiary amides in the context of molecular-wire voltage indicators prevent dye internalization and 5'-substituted voltage indicators exhibit improved voltage sensitivity should be broadly applicable to other types of PeT-based voltage-sensitive fluorophores.

  9. Electrostatic modelling of dual frequency rf plasma discharges

    Energy Technology Data Exchange (ETDEWEB)

    Boyle, P C; Ellingboe, A R; Turner, M M [Plasma Research Laboratory, National Centre for Plasma Science and Technology and School of Physical Sciences, Dublin City University, Dublin 9 (Ireland)

    2004-08-01

    Particle-in-cell simulations have been used to study the nature of dual frequency plasma discharges. It is observed that both the ion flux on to the electrodes and the ion bombardment energy on to the electrodes can be controlled independently. There are two separate regimes in which this occurs. At large electrode separation, the ion current is controlled by varying the total discharge current, J{sub lf} + J{sub hf}. At small electrode separations, the ion flux can be controlled by varying the high frequency power source. In both regimes, the energy of the ions bombarding the electrodes is then determined by the low frequency voltage. A consequence of using dual frequencies to power the device is that the sheath width increases linearly as the low frequency power source is increased. This results in the dimensions of the bulk plasma decreasing, causing the electron temperature to increase for devices with electrode separations that are of comparable size to the electrode separation. In order to better understand the underlying physics involved within these devices an analytical global model has been developed which can explain many of the characteristics observed in the simulations.

  10. Soft tissue discrimination ex vivo by dual energy computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Zachrisson, H., E-mail: helene.zachrisson@lio.s [Center for Medical Image Science and Visualization, Linkoeping University, Linkoeping University Hospital, SE-581 85 Linkoeping (Sweden); Clinical Physiology, Department of Medical and Health Sciences (IMH), Linkoeping University, Linkoeping University Hospital, SE-581 85 Linkoeping (Sweden); Engstroem, E. [Clinical Physiology, Department of Medical and Health Sciences (IMH), Linkoeping University, Linkoeping University Hospital, SE-581 85 Linkoeping (Sweden); Engvall, J.; Wigstroem, L. [Center for Medical Image Science and Visualization, Linkoeping University, Linkoeping University Hospital, SE-581 85 Linkoeping (Sweden); Clinical Physiology, Department of Medical and Health Sciences (IMH), Linkoeping University, Linkoeping University Hospital, SE-581 85 Linkoeping (Sweden); Smedby, O.; Persson, A. [Center for Medical Image Science and Visualization, Linkoeping University, Linkoeping University Hospital, SE-581 85 Linkoeping (Sweden); Radiology, Department of Medical and Health Sciences (IMH), Linkoeping University, Linkoeping University Hospital, SE-581 85 Linkoeping (Sweden)

    2010-08-15

    Purpose: Dual Energy Computed Tomography (DECT) may provide additional information about the chemical composition of tissues compared to examination with a single X-ray energy. The aim of this in vitro study was to test whether combining two energies may significantly improve the detection of soft tissue components commonly present in arterial plaques. Methods: Tissue samples of myocardial and psoas muscle, venous and arterial thrombus as well as fat from different locations were scanned using a SOMATOM Definition Dual Source CT system (Siemens AG, Medical Solutions, Forchheim, Germany) with simultaneous tube voltages of 140 and 80 kV. The attenuation (Hounsfield units, HU) at 80 and 140 kV was measured in representative regions of interest, and the association between measured HU values and tissue types was tested with logistic regression. Results: The combination of two energy levels (80 and 140 kV) significantly improved (p < 0.001) the ability to correctly classify venous thrombus vs arterial thrombus, myocardium or psoas; arterial thrombus vs myocardium or psoas; myocardium vs psoas; as well as the differentiation between fat tissue from various locations. Single energy alone was sufficient for distinguishing fat from other tissues. Conclusion: DECT offers significantly improved in vitro differentiation between soft tissues occurring in plaques. If this corresponds to better tissue discrimination in vivo needs to be clarified in future studies.

  11. A random resistor network model of voltage trimming

    Energy Technology Data Exchange (ETDEWEB)

    Grimaldi, C [Laboratoire de Production Microtechnique, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Maeder, T [Laboratoire de Production Microtechnique, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Ryser, P [Laboratoire de Production Microtechnique, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Straessler, S [Laboratoire de Production Microtechnique, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland)

    2004-08-07

    In industrial applications, the controlled adjustment (trimming) of resistive elements via the application of high voltage pulses is a promising technique, with several advantages with respect to more classical approaches such as the laser cutting method. The microscopic processes governing the response to high voltage pulses depend on the nature of the resistor and on the interaction with the local environment. Here we provide a theoretical statistical description of voltage discharge effects on disordered composites by considering random resistor network models with different properties and processes due to the voltage discharge. We compare standard percolation results with biased percolation effects and provide a tentative explanation of the different scenarios observed during trimming processes.

  12. Energy-aware Supply Voltage and Body Biasing Voltage Scheduling Algorithm for Real-time Distributed Systems

    Institute of Scientific and Technical Information of China (English)

    SUYajuan; WEIShaojun

    2005-01-01

    Technique of energy minimization by combining Dynamic voltage scheduling (DVS) and Adaptive body biasing voltage (ABB) method for distributed realtime system at design level is proposed. First, a simplified energy optimizing model is illustrated where the supply voltage or body biasing voltage is kept as constant according to each separated frequency region, thus calculation of exceeding equation is avoided. Divergence of simplified and analytic model within 5% indicates the accuracy of this model. Based on it, the proposed approach named LEVVS (Low energy supply voltage and body biasing voltage scheduling algorithm) explores space of minimizing energy consumption by finding optimal trade-off between dynamic and static energy. The corresponding optimal supply voltage and body biasing voltage are determined by an iterative method in which the supply voltage and body biasing voltage of tasks are adjusted according to the value of energy latency differential coefficient of each task and slack time distribution of the system. Experiments show that using LEVVS approach, 51% more average energy reduction can be obtained than employing DVS method alone. Furthermore the effects of switch capacitance and global slack on the energy saving efficiency of LEVVS are investigated. The smaller the global slack or average switch capacitance is, the more the energy saving of LEVVS compared with DVS is.

  13. Comparator pH study to evaluate the single-dose pharmacodynamics of dual delayed-release dexlansoprazole 60 mg and delayed-release esomeprazole 40 mg

    Directory of Open Access Journals (Sweden)

    Kukulka M

    2011-09-01

    Full Text Available Michael Kukulka1, Corey Eisenberg2, Sai Nudurupati31Clinical Pharmacology, 2Clinical Science, 3Statistics, Takeda Global Research & Development Center Inc, Deerfield, IL, USABackground: This paper describes a Phase 1, single-center, randomized, open-label, two-period crossover study which compared the pharmacodynamic effects of single doses of dexlansoprazole modified-release 60 mg and esomeprazole 40 mg on 24-hour intragastric pH in healthy adult subjects.Methods: Forty-four subjects aged 20–54 years were randomized in a 1:1 ratio to two sequence groups defining the order in which they received dexlansoprazole and esomeprazole in periods 1 and 2. Primary pharmacodynamic end points over 24 hours postdose were percentage of time with intragastric pH > 4 and mean pH, and secondary pharmacodynamic end points were percentage of time intragastric pH > 4, and mean pH at 0–12 hours, and at >12–24 hours postdose. Each drug was given after an overnight fast and one hour before breakfast. Continuous pH recording began immediately before dosing through to 24 hours postdose.Results: At 0–24 hours postdose, the mean percentage of time with pH > 4 for dexlansoprazole and esomeprazole was 58% and 48%, respectively; the difference was statistically significant (P = 0.003. The average of mean pH values at 0–24 hours postdose for dexlansoprazole and esomeprazole were 4.3 and 3.7, respectively; the difference was statistically significant (P < 0.001. At >12–24 hours postdose, mean percentage of time with pH > 4 and average of mean pH were greater for dexlansoprazole (60% and 4.5, respectively compared with esomeprazole (42% and 3.5, respectively; the difference was statistically significant (P < 0.001 for both intervals. At 0–12 hours postdose, the difference in dexlansoprazole and esomeprazole values for the pharmacodynamic end points was not statistically significant.Conclusion: For the entire 24-hour postdose period, predominantly resulting from

  14. Diode-Assisted Buck-Boost Voltage-Source Inverters

    DEFF Research Database (Denmark)

    Gao, Feng; Loh, Poh Chiang; Teodorescu, Remus;

    2009-01-01

    This paper proposes a number of diode-assisted buck-boost voltage-source inverters with a unique X-shaped diode-capacitor network inserted between the inverter circuitry and dc source for producing a voltage gain that is comparatively higher than those of other buck-boost conversion techniques...

  15. Calculation Method for Normal Inducedlongitudinal Voltage on Pilot Cable

    Directory of Open Access Journals (Sweden)

    Abdelaziz B.M. Kamel,

    2014-09-01

    Full Text Available In this paper a full study and detailed calculations of the induced voltage in pilot cables are carried out. First an introduction showing the importance of the induced voltage and its effect in pilot cables. The first calculation method Flat Formation. The second calculation method Trefoil Formation. Then the results obtained for both methods and compared. Finally a conclusion is conduct.

  16. Dual use of tobacco among Bangladeshi men

    Directory of Open Access Journals (Sweden)

    M M Zaman

    2014-01-01

    Full Text Available Introduction: Dual use of tobacco (using smoking and smokeless forms in Bangladesh is uncommon in women but common in men. Dual users are at additional risk of cancers and heart diseases compared with a single form of tobacco use. Knowledge about their socioeconomic background is necessary for planning appropriate interventions. We report here socioeconomic background of the dual users of tobacco from a nationally representative survey. Methods: The study adopted a probability proportionate to size sampling technic of divisional population stratified into urban and rural areas to recruit men aged 25 years or older from their households. A total of 4312 men were recruited. Variables included questions on 20 household assets, tobacco use and other behavioral risk factors, and measurement of body weight and height. Results: The average age of dual users was 46.7 years old compared to 43.4 and 52.3 years for smokers and smokeless tobacco users. Prevalence of "smoking only," "smokeless only" and "dual use" of tobacco was 40.6%, 15.2%, and 14.2%, respectively. Among all tobacco users, dual users constituted 20%. These dual users had lower educational achievement, rural residence, lower intake of fruit, and higher intake of alcohol. They were more undernourished as indicated by a thin body mass index compared to nonusers and smokers. Dual users were of socioeconomically deprived as measured by wealth quartiles constructed out of household assets. Conclusion: Dual use of tobacco is common in Bangladesh, and it is intimately linked with socioeconomic deprivation. Poverty reduction strategy and campaigns should address tobacco control not only tobacco in general, but its dual use in particular.

  17. THE FUNCTIONAL OUTCOME OF LOCKING VS NON-LOCKING DUAL PLATE FIXATION IN INTRAARTICULAR FRACTURE DISTAL END HUMERUS: A RETROSPECTIVE COMPARATIVE STUDY

    Directory of Open Access Journals (Sweden)

    Manish Bairagi

    2016-07-01

    Full Text Available BACKGROUND Despite all advances in treatment, it is a challenge to most of the orthopaedic surgeons to give better result in the management of distal end humerus intra-articular fractures, because it has complex anatomy. This study has been done to evaluate the functional outcome of double plate fixation with right angle to each other for intra-articular fracture of distal end humerus and compared with locking vs non-locking plate fixation. AIM This study has been done to evaluate the functional outcome of double plate fixation with right angle to each other for intraarticular fracture of distal end humerus with comparison of locking and non-locking plate fixation. METHODS This is retrospective comparative study done between 2006 and 2014 in the Department of Orthopaedics, G.R. Medical College and J.A. Group of Hospital, Gwalior (M.P., India. All patients who were presented to Department of Orthopaedics with intra-articular fracture, distal end humerus fracture, medically fit patient who were of age group between 18-80 years of age with close or type 1 GA (Gustilo Anderson compound fracture and fracture type AO type C were included. Other patients who sustained GA type 2 and 3, severely comminuted and severe osteoporotic bone were excluded. RESULT A total no. of 60 patients. The age of patients ranged from 22 to 65 years. To classifying according to AO classification, 15 cases were of type C1, 39 were of type C2 and 06 were of type C3. The results were rated using Jupiter’s criteria as excellent in 26 (43.3% cases, good in 16 (26.7%, fair in 11 (18.3% cases and poor in 07 (11.7%. CONCLUSION Double plate fixation is standard and effective method of treating intra-articular fracture of distal humerus, the method gives a stable fixation and allow early mobilization of elbow joint without risk of implant failure. In the study, there is no much advantage from the locking plate fixation in comparison with the non-locking plates.

  18. Producer gas cleaning in a dual fluidized bed reformer - a comparative study of performance with ilmenite and a manganese oxide as catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Berguerand, Nicolas; Lind, Fredrik; Seemann, Martin; Thunman, Henrik [Chalmers University of Technology, Department of Energy and Environment, Goeteborg (Sweden)

    2012-09-15

    Secondary catalytic gas conditioning is one strategy to eliminate tars formed in a producer gas during biomass gasification. However, most catalysts tend to lose their tar reforming activity after a short period of operation due to carbon formation. A novel technique for catalytic gas cleaning based on two interconnected fluidized beds has been investigated; this technique can be applied to all types of gasifiers. The idea is to reform the tar components into useful molecules - even at high tar contents - by means of a circulating catalyst. More precisely, the producer gas is cleaned with catalyst in one of the reactors, referred to as the fuel reactor, while the catalyst is continuously regenerated in another reactor, the air reactor (AR). The system described here is coupled with the Chalmers 2-4 MW{sub th} biomass gasifier while the AR is fed with nitrogen-diluted air. The effect of different catalysts on both the tar content and the gas composition was investigated. Some of the tested materials do not only reform tars, they also influence the H{sub 2}/CO ratio in a beneficial manner; in particular, ratios closer to 3 in the reformed gas are favorable if subsequent methanation is implemented. In this paper, comparative results based on testing with manganese- and iron-based catalysts are presented. The former is a manufactured catalyst while the latter is a natural ore. Results suggest that both show satisfying ability for regeneration from carbon deposits. Higher temperature enhances tar decomposition during the experiment with both catalysts. Moreover, the iron-based catalyst enhances the water-gas shift activity, which in turn impacts the total amount of produced gas. On the other hand, the manganese-based catalyst seems to display a higher propensity for tar conversion. (orig.)

  19. Dual Energy X-Ray Absorptiometry Compared with Anthropometry in Relation to Cardio-Metabolic Risk Factors in a Young Adult Population: Is the ‘Gold Standard’ Tarnished?

    Science.gov (United States)

    Hands, Beth; Pennell, Craig E.; Lye, Stephen J.; Mountain, Jennifer A.

    2016-01-01

    Background and Aims Assessment of adiposity using dual energy x-ray absorptiometry (DXA) has been considered more advantageous in comparison to anthropometry for predicting cardio-metabolic risk in the older population, by virtue of its ability to distinguish total and regional fat. Nonetheless, there is increasing uncertainty regarding the relative superiority of DXA and little comparative data exist in young adults. This study aimed to identify which measure of adiposity determined by either DXA or anthropometry is optimal within a range of cardio-metabolic risk factors in young adults. Methods and Results 1138 adults aged 20 years were assessed by DXA and standard anthropometry from the Western Australian Pregnancy Cohort (Raine) Study. Cross-sectional linear regression analyses were performed. Waist to height ratio was superior to any DXA measure with HDL-C. BMI was the superior model in relation to blood pressure than any DXA measure. Midriff fat mass (DXA) and waist circumference were comparable in relation to glucose. For all the other cardio-metabolic variables, anthropometric and DXA measures were comparable. DXA midriff fat mass compared with BMI or waist hip ratio was the superior measure for triglycerides, insulin and HOMA-IR. Conclusion Although midriff fat mass (measured by DXA) was the superior measure with insulin sensitivity and triglycerides, the anthropometric measures were better or equal with various DXA measures for majority of the cardio-metabolic risk factors. Our findings suggest, clinical anthropometry is generally as useful as DXA in the evaluation of the individual cardio-metabolic risk factors in young adults. PMID:27622523

  20. Phosphorylation of purified mitochondrial Voltage-Dependent Anion Channel by c-Jun N-terminal Kinase-3 modifies channel voltage-dependence

    Directory of Open Access Journals (Sweden)

    Rajeev Gupta

    2017-06-01

    Full Text Available Voltage-Dependent Anion Channel (VDAC phosphorylated by c-Jun N-terminal Kinase-3 (JNK3 was incorporated into the bilayer lipid membrane. Single-channel electrophysiological properties of the native and the phosphorylated VDAC were compared. The open probability versus voltage curve of the native VDAC displayed symmetry around the voltage axis, whereas that of the phosphorylated VDAC showed asymmetry. This result indicates that phosphorylation by JNK3 modifies voltage-dependence of VDAC.

  1. Electron heating and particle fluxes in dual frequency atmospheric-pressure helium capacitive discharge

    Science.gov (United States)

    Liu, Dingxin; Yang, Aijun; Wang, Xiaohua; Chen, Chen; Rong, Mingzhe; Kong, Michael G.

    2016-12-01

    In this letter, a 1D fluid model has been used to study the electron heating and particle transport in dual frequency atmospheric-pressure helium capacitive discharge with a high-frequency (HF) voltage of 10 MHz and a low-frequency (LF) voltage of 1 MHz. The electric field is decoupled to three components: the HF, the LF and the direct current (DC) ones, and they have much different effects on the plasmas. The eletrons in plasma bulk are mainly heated by the HF electric field, while in plasma sheath they are heated and cooled by the LF and DC electric fields, respectively. With a fixed total input power, the increase of LF power leads to great enhancement of the electrode fluxes of electrons and ions, especially for the energetic electrons of T e  >  2 eV, because more power is dissipated in the vicinity of electrodes and the inelastic collision is more pronounced. Therefore, the particle transport on the treated sample can be greatly enhanced without additional gas heating in dual frequency plasmas, which meets the application requirements more compared to the single frequency plasmas.

  2. A comparative study of inter-abutment distance of dies made from full arch dual-arch impression trays with those made from full arch stock trays: An in vitro study

    OpenAIRE

    Reddy Jagan; Prashanti E; Kumar G; Suresh Sajjan M; Mathew Xavier

    2009-01-01

    Objectives: The dual-arch impression technique is convenient in that it makes the required maxillary and mandibular impressions, as well as the inter-occlusal record in one procedure. The accuracy of inter-abutment distance in dies fabricated from dual-arch impression technique remains in question because there is little information available in the literature. Materials and Methods: This study was conducted to evaluate the accuracy of inter-abutment distance in dies obtained from full ar...

  3. A novel high voltage start up circuit for an integrated switched mode power supply

    Energy Technology Data Exchange (ETDEWEB)

    Hu Hao; Chen Xingbi, E-mail: huhao21@uestc.edu.c [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China)

    2010-09-15

    A novel high voltage start up circuit for providing an initial bias voltage to an integrated switched mode power supply (SMPS) is presented. An enhanced mode VDMOS transistor, the gate of which is biased by a floating p-island, is used to provide start up current and sustain high voltage. An NMOS transistor having a high source to ground breakdown voltage is included to extend the bias voltage range to the SMPS. Simulation results indicate that the high voltage start up circuit can start and restart as designed. The proposed structure is believed to be more energy saving and cost-effective compared with other solutions. (semiconductor devices)

  4. SEMICONDUCTOR DEVICES: A novel high voltage start up circuit for an integrated switched mode power supply

    Science.gov (United States)

    Hao, Hu; Xingbi, Chen

    2010-09-01

    A novel high voltage start up circuit for providing an initial bias voltage to an integrated switched mode power supply (SMPS) is presented. An enhanced mode VDMOS transistor, the gate of which is biased by a floating p-island, is used to provide start up current and sustain high voltage. An NMOS transistor having a high source to ground breakdown voltage is included to extend the bias voltage range to the SMPS. Simulation results indicate that the high voltage start up circuit can start and restart as designed. The proposed structure is believed to be more energy saving and cost-effective compared with other solutions.

  5. Dual Income Taxes

    DEFF Research Database (Denmark)

    Sørensen, Peter Birch

    This paper discusses the principles and practices of dual income taxation in the Nordic countries. The first part of the paper explains the rationale and the historical background for the introduction of the dual income tax and describes the current Nordic tax practices. The second part...... of the paper focuses on the problems of taxing income from small businesses and the issue of corporate-personal tax integration under the dual income tax, considering alternative ways of dealing with these challenges. In the third and final part of the paper, I briefly discuss whether introducing a dual income...... tax could be relevant for New Zealand....

  6. Dual Income Taxes

    DEFF Research Database (Denmark)

    Sørensen, Peter Birch

    This paper discusses the principles and practices of dual income taxation in the Nordic countries. The first part of the paper explains the rationale and the historical background for the introduction of the dual income tax and describes the current Nordic tax practices. The second part...... of the paper focuses on the problems of taxing income from small businesses and the issue of corporate-personal tax integration under the dual income tax, considering alternative ways of dealing with these challenges. In the third and final part of the paper, I briefly discuss whether introducing a dual income...... tax could be relevant for New Zealand....

  7. Dual-fuel, dual-throat engine preliminary analysis

    Science.gov (United States)

    Obrien, C. J.

    1979-01-01

    A propulsion system analysis of the dual fuel, dual throat engine for launch vehicle applications was conducted. Basic dual throat engine characterization data were obtained to allow vehicle optimization studies to be conducted. A preliminary baseline engine system was defined.

  8. Improved perovskite film quality and solar cell performances using dual single solution coating

    Science.gov (United States)

    Baltakesmez, Ali; Biber, Mehmet; Tüzemen, Sebahattin

    2017-08-01

    In this study, we present high quality perovskite CH3NH3PbI3-xClx thin films prepared by a combination of static and dynamic coating approaches, named dual single solution coating. Static coating, dynamic coating and the combination of these are comparatively studied. Scanning electron microscopy, X-ray diffraction, atomic force microscopy, UV-visible spectroscopy, and photoluminescence techniques are used for the determination of morphological, structural, and optical properties of thin films prepared using different coating approaches and deposition temperatures. All the coating approaches are repeated at room temperature and with hot deposition. The high quality and density CH3NH3PbI3-xClx films with full surface coverage are obtained using the dual single solution coating, particularly with hot-deposition. The perovskite solar cells prepared by the dual coating approach with hot deposition have better values for all the performance parameters in comparison to the other coating approaches, resulting in high efficiencies. The best device has a short circuit current of 22.03 mA/cm2, an open circuit voltage of 0.91 V, a fill factor of 0.73, and a power conversion efficiency of 14.68% from short-circuit to forward bias, and 22.39 mA/cm2, 0.91 V, 75% and 15.32% for the vice-versa, respectively.

  9. A Novel Power Reduction Technique for Dual-Threshold Domino Logic in Sub-65nm Technology

    Directory of Open Access Journals (Sweden)

    Tarun Kr. Gupta

    2013-03-01

    Full Text Available A novel technique for dual- threshold is proposed and examined with inputs and clock signals combinationin 65nm dual- threshold footerless domino circuit for reduced leakage current. In this technique a p-typeand an n-type leakage controlled transistor (LCTsare introduced between the pull-up and pull-downnetwork and the gate of one is controlled by the source of the other. A high-threshold transistor is used inthe input for reducing gate oxide leakage current which becomes dominant in nanometer technology.Simulations based on 65nm BISM4 model for proposeddomino circuits shows that CLIL (clock low andinput low and CHIH (clock high and input high state is ineffective for lowering leakage current. TheCLIH (clock low input high state is only effective to suppress the leakage at low and high temperatures forwide fan-in domino circuits but for AND gate CHIL (clock high input low state is preferred to reducetheleakage current. The proposed circuit technique forAND2, OR2, OR4 and OR8 circuits reduces the activepower consumption by 39.6% to 57.9% and by 32.4% to40.3% at low and high die temperaturesrespectively when compared to the standard dual-threshold voltage domino logic circuits.

  10. A Novel Power Reduction Technique for Dual-Threshold Domino Logic in Sub-65nm Technology

    Directory of Open Access Journals (Sweden)

    Tarun Kr. Gupta

    2013-02-01

    Full Text Available A novel technique for dual- threshold is proposed and examined with inputs and clock signals combinationin 65nm dual- threshold footerless domino circuit for reduced leakage current. In this technique a p-typeand an n-type leakage controlled transistor (LCTsare introduced between the pull-up and pull-downnetwork and the gate of one is controlled by the source of the other. A high-threshold transistor is used inthe input for reducing gate oxide leakage current which becomes dominant in nanometer technology.Simulations based on 65nm BISM4 model for proposeddomino circuits shows that CLIL (clock low andinput low and CHIH (clock high and input high state is ineffective for lowering leakage current. TheCLIH (clock low input high state is only effective to suppress the leakage at low and high temperatures forwide fan-in domino circuits but for AND gate CHIL (clock high input low state is preferred to reducetheleakage current. The proposed circuit technique forAND2, OR2, OR4 and OR8 circuits reduces the activepower consumption by 39.6% to 57.9% and by 32.4% to40.3% at low and high die temperaturesrespectively when compared to the standard dual-threshold voltage domino logic circuits.

  11. Voltage charging enhances ionic conductivity in gold nanotube membranes.

    Science.gov (United States)

    Gao, Peng; Martin, Charles R

    2014-08-26

    Ionically conductive membranes are used in many electrochemical processes and devices, including batteries, fuel cells, and electrolyzers. In all such applications, it is advantageous to use membranes with high ionic conductivity because membrane resistance causes a voltage loss suffered by the cell. We describe here a method for enhancing ionic conductivity in membranes containing small diameter (4 nm) gold nanotubes. This entails making the gold nanotube membrane the working electrode in an electrochemical cell and applying a voltage to the membrane. We show here that voltage charging in this way can increase membrane ionic conductivity by over an order of magnitude. When expressed in terms of the ionic conductivity of the electrolyte, κ, within an individual voltage-charged tube, the most negative applied voltage yielded a κ comparable to that of 1 M aqueous KCl, over 2 orders of magnitude higher than κ of the 0.01 M KCl solution contacting the membrane.

  12. Synchronised Voltage Space Vector Modulation for Three-level Inverters with Common-mode Voltage Elimination

    DEFF Research Database (Denmark)

    Oleschuk, Valentin; Blaabjerg, Frede

    2002-01-01

    of the voltage waveforms during the whole control range including overmodulation. Continuous, discontinuous and "direct-direct" schemes of synchronous PWM with both algebraic and trigonometric control functions have been analysed and compared. Simulations give the behaviour of the proposed methods and show some...

  13. Voltage Sensors Monitor Harmful Static

    Science.gov (United States)

    2009-01-01

    A tiny sensor, small enough to be worn on clothing, now monitors voltage changes near sensitive instruments after being created to alert Agency workers to dangerous static buildup near fuel operations and avionics. San Diego s Quasar Federal Systems received a Small Business Innovation Research (SBIR) contract from Kennedy Space Center to develop its remote voltage sensor (RVS), a dime-sized electrometer designed to measure triboelectric changes in the environment. One of the unique qualities of the RVS is that it can detect static at greater distances than previous devices, measuring voltage changes from a few centimeters to a few meters away, due to its much-improved sensitivity.

  14. Current and Voltage Conveyors in Current- and Voltage-Mode Precision Full-Wave Rectifiers

    Directory of Open Access Journals (Sweden)

    J. Koton

    2011-04-01

    Full Text Available In this paper new versatile precision full-wave rectifiers using current and/or voltage conveyors as active elements and two diodes are presented. The performance of these circuit solutions is analysed and compared to the opamp based precision rectifier. To analyze the behavior of the functional blocks, the frequency dependent RMS error and DC transient value are evaluated for different values of input voltage amplitudes. Furthermore, experimental results are given that show the feasibilities of the conveyor based rectifiers superior to the corresponding operational amplifier based topology.

  15. Dual-path NMR receiver using double transceiver microcoils.

    Science.gov (United States)

    Pourmodheji, Hossein; Ghafar-Zadeh, Ebrahim; Magierowski, Sebastian

    2015-01-01

    We present a fully integrated CMOS dual path front-end receiver for NMR applications. Instead of conventional NMR systems which are using one transceiver coil, we propose a dual-path receiver in which it has two transceiver microcoils. This structure cancels the background signal and consequently improving the sensitivity. Spectral simulations of the dual-path receiver are used to verify cancellation of the background signal in this structure. The front-end receiver contains two differential low-noise amplifiers (LNA), two voltage buffers (for conventional mode), two phase shifters, two variable gain amplifiers (VGA), one differential LNA and voltage buffer at the end. This chain of dual-path receiver is designed for 21 MHz NMR settings. The front-end receiver achieves an input referred noise of 2.7 nV/√Hz and voltage gain of 80 dB. The chip is designed in a 0.13-μm CMOS technology and occupies an area of 1 mm × 2 mm.

  16. Truncated Dual-Cap Nucleation Site Development

    Science.gov (United States)

    Matson, Douglas M.; Sander, Paul J.

    2012-01-01

    During heterogeneous nucleation within a metastable mushy-zone, several geometries for nucleation site development must be considered. Traditional spherical dual cap and crevice models are compared to a truncated dual cap to determine the activation energy and critical cluster growth kinetics in ternary Fe-Cr-Ni steel alloys. Results of activation energy results indicate that nucleation is more probable at grain boundaries within the solid than at the solid-liquid interface.

  17. Voltage-induced reduction of graphene oxide

    Science.gov (United States)

    Faucett, Austin C.

    Graphene Oxide (GO) is being widely researched as a precursor for the mass production of graphene, and as a versatile material in its own right for flexible electronics, chemical sensors, and energy harvesting applications. Reduction of GO, an electrically insulating material, into reduced graphene oxide (rGO) restores electrical conductivity via removal of oxygen-containing functional groups. Here, a reduction method using an applied electrical bias, known as voltage-induced reduction, is explored. Voltage-induced reduction can be performed under ambient conditions and avoids the use of hazardous chemicals or high temperatures common with standard methods, but little is known about the reduction mechanisms and the quality of rGO produced with this method. This work performs extensive structural and electrical characterization of voltage-reduced GO (V-rGO) and shows that it is competitive with standard methods. Beyond its potential use as a facile and eco-friendly processing approach, V-rGO reduction also offers record high-resolution patterning capabilities. In this work, the spatial resolution limits of voltage-induced reduction, performed using a conductive atomic force microscope probe, are explored. It is shown that arbitrary V-rGO conductive features can be patterned into insulating GO with nanoscale resolution. The localization of voltage-induced reduction to length scales < 10 nm allows studies of reduction reaction kinetics, using electrical current obtained in-situ, with statistical robustness. Methods for patterning V-rGO nanoribbons are then developed. After presenting sub-10nm patterning of V-rGO nanoribbons in GO single sheets and films, the performance of V-rGO nanoribbon field effect transistors (FETs) are demonstrated. Preliminary measurements show an increase in electrical current on/off ratios as compared to large-area rGO FETs, indicating transport gap modulation that is possibly due to quantum confinement effects.

  18. A study on threshold voltage stability of low operating voltage organic thin-film transistors

    Science.gov (United States)

    Padma, N.; Sen, Shaswati; Sawant, Shilpa N.; Tokas, R.

    2013-08-01

    A low operating voltage (<2 V) organic field-effect transistor (OFET) using phenylhexyltrichlorosilane (PTS) self-assembled monolayer (SAM) dielectric and copper phthalocyanine (CuPc) as semiconductor with improved mobility (0.035 cm2 V-1 s-1) and threshold voltage stability was demonstrated. This device showed better performance when compared to an OFET with octyltrichlorosilane (OTS-8) SAM dielectric. The improved mobility was attributed to the 2D growth mode of CuPc on PTS SAM because of surface energy matching between the two, whereas CuPc film on OTS-8 showed a 3D growth mode with larger grain boundary density. The higher threshold voltage stability of OFETs on PTS SAM was attributed to the efficient coverage and screening of trap centres at dielectric/semiconductor interface due to stronger intermolecular linking and formation of closely packed surface by the bulky phenyl end groups. Decrease in grain boundaries offered by 2D growth of CuPc for electron and hole trapping was also found to be another reason for improved threshold voltage stability. The results indicated that the nature of the end group of SAM dielectric, surface chemistry of dielectric and initial growth mode of semiconductors are all responsible for improvement in threshold voltage stability and enhanced performance of OFET.

  19. Load distribution model and voltage static profile of Smart Grid

    Institute of Scientific and Technical Information of China (English)

    SUN Qiu-ye; LI Zhong-xu; YANG Jun; LUO Yan-hong

    2010-01-01

    Voltage profiles of feeders with the connection of distributed generations(DGs)were investigated.A unified typical load distribution model was established.Based on this model,exact expressions of feeder voltage profile with single and double DGs were derived and used to analyze the impact of DG's location and capacity on the voltage profile quantitatively.Then,a general formula of the voltage profile was derived.The limitation of single DG and necessity of multiple DGs for voltage regulation were also discussed.Through the simulation,voltage profiles of feeders with single and double DGs were compared.The voltage excursion rate is 7.40% for only one DG,while 2.48% and 2.36% for double DGs.It is shown that the feeder voltage can be retained in a more appropriate range with multiple DGs than with only one DG.Distributing the total capacity of DGs is better than concentrating it at one point.

  20. Low Voltage Power Supply Incorporating Ceramic Transformer

    CERN Document Server

    Imori, M

    2007-01-01

    A low voltage power supply provides the regulated output voltage of 1 V from the supply voltage around 48 V. The low voltage power supply incorporates a ceramic transformer which utilizes piezoelectric effect to convert voltage. The ceramic transformer isolates the secondary from the primary, thus providing the ground isolation between the supply and the output voltages. The ceramic transformer takes the place of the conventional magnetic transformer. The ceramic transformer is constructed from a ceramic bar and does not include any magnetic material. So the low voltage power supply can operate under a magnetic field. The output voltage is stabilized by feedback. A feedback loop consists of an error amplifier, a voltage controlled oscillator and a driver circuit. The amplitude ratio of the transformer has dependence on the frequency, which is utilized to stabilize the output voltage. The low voltage power supply is investigated on the analogy of the high voltage power supply similarly incorporating the cerami...

  1. A magnesium–sodium hybrid battery with high operating voltage

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Hui; Li, Yifei; Liang, Yanliang; Li, Guosheng; Sun, Cheng-Jun; Ren, Yang; Lu, Yuhao; Yao, Yan

    2016-06-10

    We report a high performance magnesium-sodium hybrid battery utilizing a magnesium-sodium dual-salt electrolyte, a magnesium anode, and a Berlin green cathode. The cell delivers an average discharge voltage of 2.2 V and a reversible capacity of 143 mAh g-1. We also demonstrate the cell with an energy density of 135 Wh kg-1 and a high power density of up to 1.67 kW kg-1.

  2. Modular High Voltage Power Supply

    Energy Technology Data Exchange (ETDEWEB)

    Newell, Matthew R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-05-18

    The goal of this project is to develop a modular high voltage power supply that will meet the needs of safeguards applications and provide a modular plug and play supply for use with standard electronic racks.

  3. Reliability criteria for voltage stability

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Carson W.; Silverstein, Brian L. [Bonneville Power Administration, Portland, OR (United States)

    1994-12-31

    In face of costs pressures, there is need to allocate scare resources more effectively in order to achieve voltage stability. This naturally leads to development of probabilistic criteria and notions of rick management. In this paper it is presented a discussion about criteria for long term voltage stability limited to the case in which the time frames are topically several minutes. (author) 14 refs., 1 fig.

  4. A Voltage Quality Detection Method

    DEFF Research Database (Denmark)

    Chen, Zhe; Wei, Mu

    2008-01-01

    This paper presents a voltage quality detection method based on a phase-locked loop (PLL) technique. The technique can detect the voltage magnitude and phase angle of each individual phase under both normal and fault power system conditions. The proposed method has the potential to evaluate vario...... power quality disturbances, such as interruptions, sags and imbalances. Simulation studies have been performed. The effectiveness of the proposed method has been demonstrated under the simulated typical power disturbances....

  5. The Dual Career Family.

    Science.gov (United States)

    Gurtin, Lee

    1980-01-01

    The dual career couple is forced to make a series of choices and compromises that impact the realms of marriage and career. The dilemmas that confront dual career marriages can be overcome only by compromise, accommodation, and mutual understanding on the part of the individuals involved. A revamping of human resources and recruitment programs is…

  6. Dual Credit Report

    Science.gov (United States)

    Light, Noreen

    2016-01-01

    In 2015, legislation to improve access to dual-credit programs and to reduce disparities in access and completion--particularly for low income and underrepresented students--was enacted. The new law focused on expanding access to College in the High School but acknowledged issues in other dual-credit programs and reinforced the notion that cost…

  7. Dual Youla parameterization

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik

    2003-01-01

    A different aspect of using the parameterisation of all systems stabilised by a given controller, i.e. the dual Youla parameterisation, is considered. The relation between system change and the dual Youla parameter is derived in explicit form. A number of standard uncertain model descriptions are...

  8. Self-Dual Gravity

    CERN Document Server

    Krasnov, Kirill

    2016-01-01

    Self-dual gravity is a diffeomorphism invariant theory in four dimensions that describes two propagating polarisations of the graviton and has a negative mass dimension coupling constant. Nevertheless, this theory is not only renormalisable but quantum finite, as we explain. We also collect various facts about self-dual gravity that are scattered across the literature.

  9. Optical dual self functions

    Institute of Scientific and Technical Information of China (English)

    华建文; 刘立人; 王宁

    1997-01-01

    A recipe to construct the exact dual self-Fourier-Fresnel-transform functions is shown, where the Dirac comb function and transformable even periodic function are used. The mathematical proof and examples are given Then this kind of self-transform function is extended to the feasible optical dual self-transform functions.

  10. Dual doubled geometry

    NARCIS (Netherlands)

    Bergshoeff, Eric A.; Riccioni, Fabio; Alvarez-Gaumé, L.

    2011-01-01

    We probe doubled geometry with dual fundamental branes. i.e. solitons. Restricting ourselves first to solitonic branes with more than two transverse directions we find that the doubled geometry requires an effective wrapping rule for the solitonic branes which is dual to the wrapping rule for fundam

  11. GaAs integrated digital-to-analogue convertor for control of power dual-gate FETs

    Science.gov (United States)

    Saunier, P.; Kim, B.; Frensley, W. R.

    1983-01-01

    The design, fabrication and performance of a TTL compatible 4-bit GaAs integrated digital-to-analog convertor with an output voltage between -2.8 V and +2.8 V are reported. This circuit has been especially designed to control the gain of power dual-gate FETs by applying a voltage on the capacitively terminated second gate.

  12. Optimized Carrier Based Multilevel Generated Modified Dual Three-Phase Open-Winding Inverter for Medium Power Applications

    DEFF Research Database (Denmark)

    Padmanaban, Sanjeevi Kumar; Blaabjerg, Frede; Wheeler, Patrick

    2016-01-01

    This paper presents a novel carrier based multilevel modulation for modified dual three-phase open-winding inverter applicable for low-voltage/high-current applications. A standard three-phase voltage source inverter (VSI) is connected across the open-winding of both ends of the motor. Each VSI i...

  13. Semiquantitative assessment of focal cartilage damage at 3 T MRI: A comparative study of dual echo at steady state (DESS) and intermediate-weighted (IW) fat suppressed fast spin echo sequences

    Energy Technology Data Exchange (ETDEWEB)

    Roemer, Frank W., E-mail: froemer@bu.edu [Quantitative Imaging Center (QIC), Department of Radiology, Boston University Medical Center, Boston, MA (United States); Department of Radiology, Klinikum Augsburg, Augsburg (Germany); Kwoh, C. Kent [Division of Rheumatology and Clinical Immunology, University of Pittsburgh School of Medicine (United States); VA Pittsburgh Healthcare System (United States); Hannon, Michael J. [Division of Rheumatology and Clinical Immunology, University of Pittsburgh School of Medicine (United States); Crema, Michel D. [Quantitative Imaging Center (QIC), Department of Radiology, Boston University Medical Center, Boston, MA (United States); Moore, Carolyn E. [Department of Nutrition and Food Sciences, Texas Woman' s University (United States); Jakicic, John M. [Department of Health and Physical Activity, University of Pittsburgh (United States); Green, Stephanie M. [Division of Rheumatology and Clinical Immunology, University of Pittsburgh School of Medicine (United States); Guermazi, Ali [Quantitative Imaging Center (QIC), Department of Radiology, Boston University Medical Center, Boston, MA (United States)

    2011-11-15

    Purpose: The aim of the study was to compare semiquantitative assessment of focal cartilage damage using the dual echo at steady state (DESS)- and intermediate-weighted (IW) fat suppressed (fs) sequences at 3 T MRI. Methods: Included were 201 subjects aged 35-65 with frequent knee pain. MRI was performed with the same sequence protocol as in the Osteoarthritis Initiative (OAI): sagittal IW fs, triplanar DESS and coronal IW sequences. Cartilage status was scored according to the WORMS system using all five sequences. A total of 243 focal defects were detected. In an additional consensus reading, the lesions were evaluated side-by-side using only the sagittal DESS and IW fs sequences. Lesion conspicuity was graded from 0 to 3, intrachondral signal changes adjacent to the defect were recorded and the sequence that depicted the lesion with larger diameter was noted. Wilcoxon signed-rank tests, controlled for clustering by person, were used to examine differences between the sequences. Results: 37 (17.5%) of the scorable lesions were located in the medial tibio-femoral (TF), 48 (22.7%) in the lateral TF and 126 (59.7%) in the patello-femoral compartment. 82.5% were superficial and 17.5% full-thickness defects. Conspicuity was superior for the IW sequence (p < 0.001). The DESS sequence showed more associated intrachondral signal changes (p < 0.001). In 103 (48.8%) cases, the IW fs sequence depicted the lesions as being larger (p < 0.001). Conclusions: The IW fs sequence detected more and larger focal cartilage defects than the DESS. More intrachondral signal changes were observed with the DESS.

  14. A matter of quantum voltages.

    Science.gov (United States)

    Sellner, Bernhard; Kathmann, Shawn M

    2014-11-14

    Voltages inside matter are relevant to crystallization, materials science, biology, catalysis, and aqueous chemistry. The variation of voltages in matter can be measured by experiment, however, modern supercomputers allow the calculation of accurate quantum voltages with spatial resolutions of bulk systems well beyond what can currently be measured provided a sufficient level of theory is employed. Of particular interest is the Mean Inner Potential (V(o))--the spatial average of these quantum voltages referenced to the vacuum. Here we establish a protocol to reliably evaluate V(o) from quantum calculations. Voltages are very sensitive to the distribution of electrons and provide metrics to understand interactions in condensed phases. In the present study, we find excellent agreement with measurements of V(o) for vitrified water and salt crystals and demonstrate the impact of covalent and ionic bonding as well as intermolecular/atomic interactions. Certain aspects in this regard are highlighted making use of simple model systems/approximations. Furthermore, we predict V(o) as well as the fluctuations of these voltages in aqueous NaCl electrolytes and characterize the changes in their behavior as the resolution increases below the size of atoms.

  15. Research on Dual Control

    Institute of Scientific and Technical Information of China (English)

    Duan Li; Fucai Qian; Peilin Fu

    2005-01-01

    This paper summarizes recent progress by the authors in developing two solution frameworks for dual control. The first solution framework considers a class of dual control problems where there exists a parameter uncertainty in the observation equation of the LQG problem. An analytical active dual control law is derived by a variance minimization approach. The issue of how to determine an optimal degree of active learning is then addressed, thus achieving an optimality for this class of dual control problems. The second solution framework considers a general class of discrete-time LQG problems with unknown parameters in both state and observation equations. The best possible (partial) closed-loop feedback control law is derived by exploring the future nominal posterior probabilities, thus taking into account the effect of future learning when constructing the optimal nominal dual control.

  16. VOLTAGE COMPENSATION USING ARTIFICIAL NEURAL NETWORK

    African Journals Online (AJOL)

    VOLTAGE COMPENSATION USING ARTIFICIAL NEURAL NETWORK: A CASE STUDY OF RUMUOLA DISTRIBUTION NETWORK. ... The artificial neural networks controller engaged to controlling the dynamic voltage ... Article Metrics.

  17. Fast response double series resonant high-voltage DC-DC converter

    Science.gov (United States)

    Lee, S. S.; Iqbal, S.; Kamarol, M.

    2012-10-01

    In this paper, a novel double series resonant high-voltage dc-dc converter with dual-mode pulse frequency modulation (PFM) control scheme is proposed. The proposed topology consists of two series resonant tanks and hence two resonant currents flow in each switching period. Moreover, it consists of two high-voltage transformer with the leakage inductances are absorbed as resonant inductor in the series resonant tanks. The secondary output of both transformers are rectified and mixed before supplying to load. In the resonant mode operation, the series resonant tanks are energized alternately by controlling two Insulated Gate Bipolar Transistor (IGBT) switches with pulse frequency modulation (PFM). This topology operates in discontinuous conduction mode (DCM) with all IGBT switches operating in zero current switching (ZCS) condition and hence no switching loss occurs. To achieve fast rise in output voltage, a dual-mode PFM control during start-up of the converter is proposed. In this operation, the inverter is started at a high switching frequency and as the output voltage reaches 90% of the target value, the switching frequency is reduced to a value which corresponds to the target output voltage. This can effectively reduce the rise time of the output voltage and prevent overshoot. Experimental results collected from a 100-W laboratory prototype are presented to verify the effectiveness of the proposed system.

  18. Optimal coordinated voltage control of power systems

    Institute of Scientific and Technical Information of China (English)

    LI Yan-jun; HILL David J.; WU Tie-jun

    2006-01-01

    An immune algorithm solution is proposed in this paper to deal with the problem of optimal coordination of local physically based controllers in order to preserve or retain mid and long term voltage stability. This problem is in fact a global coordination control problem which involves not only sequencing and timing different control devices but also tuning the parameters of controllers. A multi-stage coordinated control scheme is presented, aiming at retaining good voltage levels with minimal control efforts and costs after severe disturbances in power systems. A self-pattern-recognized vaccination procedure is developed to transfer effective heuristic information into the new generation of solution candidates to speed up the convergence of the search procedure to global optima. An example of four bus power system case study is investigated to show the effectiveness and efficiency of the proposed algorithm, compared with several existing approaches such as differential dynamic programming and tree-search.

  19. Tunable Dual-band IFA Antenna using LC Resonators

    CERN Document Server

    Ni, Nan

    2011-01-01

    A tunable dual-band inverted F antenna (IFA) is presented in this paper. By placing a LC resonator on the radiating arm, dual-band characteristic is achieved. Especially, the capacitor in the resonator is a tunable thin-film BST capacitor, which has a 3.3:1 tuning ratio. The capacitance of the BST capacitors can be tuned by an external DC bias voltage. By varying the capacitance, both the lower band and the upper band of the IFA antenna can be tuned. And the total bandwidth can cover six systems, i.e., GSM-850, GSM-900, GPS, DCS, PCS, and UMTS.

  20. Simulation of Dual-Electrode Capacitively Coupled Plasma Discharges

    Science.gov (United States)

    Lu, Yijia; Ji, Linhong; Cheng, Jia

    2016-12-01

    Dual-electrode capacitively coupled plasma discharges are investigated here to lower the non-uniformity of plasma density. The dual-electrode structure proposed by Jung splits the electrode region and increases the flexibility of fine tuning non-uniformity. Different RF voltages, frequencies, phase-shifts and electrode areas are simulated and the influences are discussed. RF voltage and electrode area have a non-monotonic effect on non-uniformity, while frequency has a monotonic effect. Phase-shift has a cyclical influence on non-uniformity. A special combination of 224 V voltage and 11% area ratio with 10 MHz lowers the non-uniformity of the original set (200 V voltage and 0% area ratio with 10 MHz) by 46.5%. The position of the plasma density peak at the probe line has been tracked and properly tuning the phase-shift can obtain the same trace as tuning frequency or voltage. supported by National Natural Science Foundation of China (No. 51405261)

  1. Simulation of dual transponder carrier ranging measurements

    Institute of Scientific and Technical Information of China (English)

    Xiang-yu ZHAO; Xiao-jun JIN; Zhong-he JIN

    2009-01-01

    The most dominant error source for microwave ranging is the frequency instability of the oscillator that generates the carrier phase signal. The oscillator noise is very difficult to filter due to its extremely low frequency. A dual transponder carrier ranging method can effectively minimize the oscillator noise by combing the reference phase and the to-and-fro measurement phase from the same single oscillator. This method does not require an accurate time tagging system, since it extracts phases on the same satellite. This paper analyzes the dual transponder carrier ranging system by simulation of the phase measurements with comprehensive error models. Both frequency domain and time domain noise transfer characteristics were simulated to compare them with dual one-way ranging. The simulation results in the two domains conformed to each other and demonstrated that a high level of accuracy can also be achieved by use of the dual transponder carrier ranging system, with relatively simple instruments.

  2. Assessment of Adaptive Rate Response Provided by Accelerometer, Minute Ventilation and Dual Sensor Compared with Normal Sinus Rhythm During Exercise: A Self-controlled Study in Chronotropically Competent Subjects

    Institute of Scientific and Technical Information of China (English)

    Yuanyuan Cao; Yiqun Zhang; Yangang Su; Jin Bai; Wei Wang; Junbo Ge

    2015-01-01

    Background:Dual sensor (DS) for rate adaption was supposed to be more physiological.To evaluate its superiority,the DS (accelerometer [ACC] and minute ventilation [MV]) and normal sinus rate response were compared in a self-controlled way during exercise treadmill testing.Methods:This self-controlled study was performed in atrioventricular block patients with normal sinus function who met the indications of pacemaker implant.Twenty-one patients came to the 1-month follow-up visit.Patients performed a treadmill test 1-month post implant while programmed in DDDR and sensor passive mode.For these patients,sensor response factors were left at default settings (ACC =8,MV =3) and sensor indicated rates (SIRs) for DS,ACC and MV sensor were retrieved from the pacemaker memories,along with measured sinus node (SN) rates from the beginning to 1-minute after the end of the treadmill test,and compared among study groups.Repeated measures analysis of variance and profile analysis,as well as variance analysis of randomized block designs,were used for statistical analysis.Results:Fifteen patients (15/2 l) were determined to be chronotropically competent.The mean differences between DS SIRs and intrinsic sinus rates during treadmill testing were smaller than those for ACC and MV sensor (mean difference between SIR and SN rate:ACC vs.SN,MV vs.SN,DS vs.SN,respectively,34.84,17.60,16.15 beats/min),though no sensors could mimic sinus rates under the default settings for sensor response factor (ACC vs.SN P-adjusted < 0.001; MV vs.SN P-adjusted =0.002; DS vs.SN P-adjusted =0.005).However,both in the range of 1st minute and first 3 minutes of exercise,only the DS SIR profile did not differ from sinus rates (P-adjusted =0.09,0.90,respectively).Conclusions:The DS under default settings provides more physiological rate response during physical activity than the corresponding single sensors (ACC or MV sensor).Further study is needed to determine if individual optimization would further

  3. Assessment of Adaptive Rate Response Provided by Accelerometer, Minute Ventilation and Dual Sensor Compared with Normal Sinus Rhythm During Exercise: A Self-controlled Study in Chronotropically Competent Subjects

    Directory of Open Access Journals (Sweden)

    Yuanyuan Cao

    2015-01-01

    Full Text Available Background: Dual sensor (DS for rate adaption was supposed to be more physiological. To evaluate its superiority, the DS (accelerometer [ACC] and minute ventilation [MV] and normal sinus rate response were compared in a self-controlled way during exercise treadmill testing. Methods: This self-controlled study was performed in atrioventricular block patients with normal sinus function who met the indications of pacemaker implant. Twenty-one patients came to the 1-month follow-up visit. Patients performed a treadmill test 1-month post implant while programmed in DDDR and sensor passive mode. For these patients, sensor response factors were left at default settings (ACC = 8, MV = 3 and sensor indicated rates (SIRs for DS, ACC and MV sensor were retrieved from the pacemaker memories, along with measured sinus node (SN rates from the beginning to 1-minute after the end of the treadmill test, and compared among study groups. Repeated measures analysis of variance and profile analysis, as well as variance analysis of randomized block designs, were used for statistical analysis. Results: Fifteen patients (15/21 were determined to be chronotropically competent. The mean differences between DS SIRs and intrinsic sinus rates during treadmill testing were smaller than those for ACC and MV sensor (mean difference between SIR and SN rate: ACC vs. SN, MV vs. SN, DS vs. SN, respectively, 34.84, 17.60, 16.15 beats/min, though no sensors could mimic sinus rates under the default settings for sensor response factor (ACC vs. SN P-adjusted < 0.001; MV vs. SN P-adjusted = 0.002; DS vs. SN P-adjusted = 0.005. However, both in the range of 1 st minute and first 3 minutes of exercise, only the DS SIR profile did not differ from sinus rates (P-adjusted = 0.09, 0.90, respectively. Conclusions: The DS under default settings provides more physiological rate response during physical activity than the corresponding single sensors (ACC or MV sensor. Further study is needed to

  4. Dual Credit/Dual Enrollment and Data Driven Policy Implementation

    Science.gov (United States)

    Lichtenberger, Eric; Witt, M. Allison; Blankenberger, Bob; Franklin, Doug

    2014-01-01

    The use of dual credit has been expanding rapidly. Dual credit is a college course taken by a high school student for which both college and high school credit is given. Previous studies provided limited quantitative evidence that dual credit/dual enrollment is directly connected to positive student outcomes. In this study, predictive statistics…

  5. Electrode voltage fall and total voltage of a transient arc

    Science.gov (United States)

    Valensi, F.; Ratovoson, L.; Razafinimanana, M.; Masquère, M.; Freton, P.; Gleizes, A.

    2016-06-01

    This paper deals with an experimental study of the components of a transient arc total voltage with duration of a few tens of ms and a current peak close to 1000 A. The cathode tip is made of graphite whereas the flat anode is made either of copper or of graphite; the electrodes gap is a few mm. The analysis of the electrical parameters is supported and validated by fast imaging and by two models: the first one is a 2D physical model of the arc allowing to calculate both the plasma temperature field and the arc voltage; the second model is able to estimate the transient heating of the graphite electrode. The main aim of the study was to detect the possible change of the cathode voltage fall (CVF) during the first instants of the arc. Indeed it is expected that during the first ms the graphite cathode is rather cool and the main mechanism of the electron emission should be the field effect emission, whereas after several tens of ms the cathode is strongly heated and thermionic emission should be predominant. We have observed some change in the apparent CVF but we have shown that this apparent change can be attributed to the variation of the solid cathode resistance. On the other hand, the possible change of CVF corresponding to the transition between a ‘cold’ and a ‘hot’ cathode should be weak and could not be characterized considering our measurement uncertainty of about 2 V. The arc column voltage (ACV) was estimated by subtracting the electrode voltage fall from the total arc voltage. The experimental transient evolution of the ACV is in very good agreement with the theoretical variation predicted by the model, showing the good ability of the model to study this kind of transient arc.

  6. 50V All-PMOS Charge Pumps Using Low-Voltage Capacitors

    KAUST Repository

    Emira, Ahmed

    2012-10-06

    In this work, two high-voltage charge pumps are introduced. In order to minimize the area of the pumping capacitors, which dominates the overall area of the charge pump, high density capacitors have been utilized. Nonetheless, these high density capacitors suffer from low breakdown voltage which is not compatible with the targeted high voltage application. To circumvent the breakdown limitation, a special clocking scheme is used to limit the maximum voltage across any pumping capacitor. The two charge pump circuits were fabricated in a 0:6m CMOS technology with poly0-poly1 capacitors. The output voltage of the two charge pumps reached 42:8V and 51V while the voltage across any capacitor did not exceed the value of the input voltage. Compared to other designs reported in the literature, the proposed charge pump provides the highest output voltage which makes it more suitable for tuning MEMS devices.

  7. Unbalanced Voltage Compensation in Low Voltage Residential AC Grids

    DEFF Research Database (Denmark)

    Trintis, Ionut; Douglass, Philip; Munk-Nielsen, Stig

    2016-01-01

    This paper describes the design and test of a control algorithm for active front-end rectifiers that draw power from a residential AC grid to feed heat pump loads. The control algorithm is able to control the phase to neutral or phase to phase RMS voltages at the point of common coupling....... The voltage control was evaluated with either active or reactive independent phase load current control. The control performance in field operation in a residential grid situated in Bornholm, Denmark was investigated for different use cases....

  8. Automated Voltage Control in LHCb

    CERN Document Server

    Granado Cardoso, L; Jacobsson, R

    2011-01-01

    LHCb is one of the 4 LHC experiments. In order to ensure the safety of the detector and to maximize efficiency, LHCb needs to coordinate its own operations, in particular the voltage configuration of the different subdetectors, according to the accelerator status. A control software has been developed for this purpose, based on the Finite State Machine toolkit and the SCADA system used for control throughout LHCb (and the other LHC experiments). This software permits to efficiently drive both the Low Voltage (LV) and High Voltage (HV) systems of the 10 different sub-detectors that constitute LHCb, setting each sub-system to the required voltage (easily configurable at run-time) based on the accelerator state. The control software is also responsible for monitoring the state of the Sub-detector voltages and adding it to the event data in the form of status-bits. Safe and yet flexible operation of the LHCb detector has been obtained and automatic actions, triggered by the state changes of the ...

  9. Design of A Novel High Speed Dynamic Comparator with Low Power Dissipation for High Speed ADCs

    Directory of Open Access Journals (Sweden)

    Sougata Ghosh

    2013-01-01

    Full Text Available A new CMOS dynamic comparator using dual input single output differential amplifier as latch stage suitable for high speed analog-to-digital converters with High Speed, low power dissipation and immune to noise than the previous reported work is proposed. Back to-back inverter in the latch stage is replaced with dual-input single output differential amplifier. This topology completely removes the noise that is present in the input. The structure shows lower power dissipation and higher speed than the conventional comparators. The circuit is simulated with 1V DC supply voltage and 250 MHz clock frequency. The proposed topology is based on two cross coupled differential pairs positive feedback and switchable current sources, has a lower power dissipation, higher speed, less area, and it is shown to be very robust against transistor mismatch, noise immunity. Previous reported comparators are designed and simulated their DC response and Transient response in Cadence®Virtuoso Analog Design Environment using GPDK 90nm technology. Layouts of the proposed comparator have been done in Cadence® Virtuoso Layout XL Design Environment. DRC and LVS has been checked and compared with the corresponding circuits and RC extracted diagram has been generated. After that post layout simulation with 1V supply voltage has been done and compared the speed, power dissipation, Area, delay with the results before layout and the superior features of the proposed comparator are established

  10. Dual coil ignition system

    Energy Technology Data Exchange (ETDEWEB)

    Huberts, Garlan J.; Qu, Qiuping; Czekala, Michael Damian

    2017-03-28

    A dual coil ignition system is provided. The dual coil ignition system includes a first inductive ignition coil including a first primary winding and a first secondary winding, and a second inductive ignition coil including a second primary winding and a second secondary winding, the second secondary winding connected in series to the first secondary winding. The dual coil ignition system further includes a diode network including a first diode and a second diode connected between the first secondary winding and the second secondary winding.

  11. Frequency to Voltage Converter Analog Front-End Prototype

    Science.gov (United States)

    Mata, Carlos; Raines, Matthew

    2012-01-01

    The frequency to voltage converter analog front end evaluation prototype (F2V AFE) is an evaluation board designed for comparison of different methods of accurately extracting the frequency of a sinusoidal input signal. A configurable input stage is routed to one or several of five separate, configurable filtering circuits, and then to a configurable output stage. Amplifier selection and gain, filter corner frequencies, and comparator hysteresis and voltage reference are all easily configurable through the use of jumpers and potentiometers.

  12. Low-Energy Real-Time OS Using Voltage Scheduling Algorithm for Variable Voltage Processors

    OpenAIRE

    Okuma, Takanori; Yasuura, Hiroto

    2001-01-01

    This paper presents a real-time OS based on $ mu $ITRON using proposed voltage scheduling algorithm for variable voltage processors which can vary supply voltage dynamically. The proposed voltage scheduling algorithms assign voltage level for each task dynamically in order to minimize energy consumption under timing constraints. Using the presented real-time OS, running tasks with low supply voltage leads to drastic energy reduction. In addition, the presented voltage scheduling algorithm is ...

  13. Simple buck/boost voltage regulator

    Science.gov (United States)

    Paulkovich, J.; Rodriguez, G. E.

    1980-01-01

    Circuit corrects low or high supply voltage, produces regulated output voltage. Circuit has fewer components because inductory/transformer combination and pulse-width modulator serve double duty. Regulator handles input voltage variation from as low as one half output voltage to as high as input transistor rating. Solar arrays, fuel cells, and thermionic generators might use this regulator.

  14. 30 CFR 18.47 - Voltage limitation.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Voltage limitation. 18.47 Section 18.47 Mineral... § 18.47 Voltage limitation. (a) A tool or switch held in the operator's hand or supported against his... particular voltage(s) are provided in the design and construction of the equipment, its wiring,...

  15. Cavity Voltage Phase Modulation MD

    CERN Document Server

    Mastoridis, Themistoklis; Molendijk, John; Timko, Helga; CERN. Geneva. ATS Department

    2016-01-01

    The LHC RF/LLRF system is currently configured for extremely stable RF voltage to minimize transient beam loading effects. The present scheme cannot be extended beyond nominal beam current since the demanded power would exceed the peak klystron power and lead to saturation. A new scheme has therefore been proposed: for beam currents above nominal (and possibly earlier), the cavity phase modulation by the beam will not be corrected (transient beam loading), but the strong RF feedback and One-Turn Delay feedback will still be active for loop and beam stability in physics. To achieve this, the voltage set point will be adapted for each bunch. The goal of this MD was to test a new algorithm that would adjust the voltage set point to achieve the cavity phase modulation that would minimize klystron forward power.

  16. Dual Z-Source Inverter With Three-Level Reduced Common-Mode Switching

    DEFF Research Database (Denmark)

    Gao, Feng; Loh, Poh Chiang; Blaabjerg, Frede;

    2007-01-01

    . Modulationwise, the dual inverter can be controlled using a carefully designed carrier-based pulsewidth-modulation (PWM) scheme that will always ensure balanced voltage boosting of the Z-source network while simultaneously achieving reduced common-mode switching. Because of the omission of dead-time delays...... in the dual-inverter PWM scheme, its switched common-mode voltage can be completely eliminated, unlike in traditional inverters, where narrow common-mode spikes are still generated. Under semiconductor failure conditions, the presented PWM schemes can easily be modified to allow the inverter to operate......This paper presents the design of a dual Z-source inverter that can be used with either a single dc source or two isolated dc sources. Unlike traditional inverters, the integration of a properly designed Z-source network and semiconductor switches to the proposed dual inverter allows buck...

  17. A multiple-pass ring oscillator based dual-loop phase-locked loop

    Institute of Scientific and Technical Information of China (English)

    Chen Danfeng; Ren Junyan; Deng Jingjing; Li Wei; Li Ning

    2009-01-01

    A dual-loop phase-locked loop (PLL) for wideband operation is proposed. The dual-loop architecture combines a coarse-tuning loop with a fine-tuning one, enabling a wide tuning range and low voltage-controlled oscillator (VCO) gain without poisoning phase noise and reference spur suppression performance. An analysis of the phase noise and reference spur of the dual-loop PLL is emphasized. A novel multiple-pass ring VCO is designed for the dual-loop application. It utilizes both voltage-control and current-control simultaneously in the delay cell. The PLL is fabricated in Jazz 0.18-μm RF CMOS technology. The measured tuning range is from 4.2 to 5.9 GHz. It achieves a low phase noise of-99 dBc/Hz @ 1 MHz offset from a 5.5 GHz carrier.

  18. A multiple-pass ring oscillator based dual-loop phase-locked loop

    Energy Technology Data Exchange (ETDEWEB)

    Chen Danfeng; Ren Junyan; Deng Jingjing; Li Wei; Li Ning, E-mail: dfchen@fudan.edu.c [State Key Laboratory of ASIC and System, Fudan University, Shanghai 201203 (China)

    2009-10-15

    A dual-loop phase-locked loop (PLL) for wideband operation is proposed. The dual-loop architecture combines a coarse-tuning loop with a fine-tuning one, enabling a wide tuning range and low voltage-controlled oscillator (VCO) gain without poisoning phase noise and reference spur suppression performance. An analysis of the phase noise and reference spur of the dual-loop PLL is emphasized. A novel multiple-pass ring VCO is designed for the dual-loop application. It utilizes both voltage-control and current-control simultaneously in the delay cell. The PLL is fabricated in Jazz 0.18-{mu}m RF CMOS technology. The measured tuning range is from 4.2 to 5.9 GHz. It achieves a low phase noise of -99 dBc/Hz - 1 MHz offset from a 5.5 GHz carrier.

  19. A dual-amplifier hot-wire anemometer

    Science.gov (United States)

    Sadeh, W. Z.; Finn, C. L.

    1979-01-01

    The conceptual design of a dual-amplifier constant-temperature hot-wire anemometer is described. This hot-wire anemometer consists of three basic independent modules: a Wheatstone bridge in which the hot wire is one of its arms, an error-correction amplifier, and a voltage-controlled current source. The last two modules constitute the feedback network of this hot-wire anemometer. Thus the output voltage across the wire is a true function of the instantaneous changes in the wire resistance induced by the cooling effect of the flow. The dual-amplifier is capable of reaching relatively high frequency response through adequate selection of its active elements. Suitable gain of the error-correction amplifier and proper choice of the transfer function of the current source has yielded a frequency bandwidth up to 200 kHz.

  20. High-performance AlGaN-based solar-blind avalanche photodiodes with dual-periodic III-nitride distributed Bragg reflectors

    Science.gov (United States)

    Yao, Chujun; Ye, Xuanchao; Sun, Rui; Yang, Guofeng; Wang, Jin; Lu, Yanan; Yan, Pengfei; Cao, Jintao; Gao, Shumei

    2017-03-01

    Separate absorption and multiplication AlGaN solar-blind avalanche photodiodes with dual-periodic III-nitride distributed Bragg reflectors (DBRs) are numerically demonstrated. The designed devices exhibit an improved solar-blind characteristic with a maximum spectral responsivity of 0.184 A/W at λ = 284 nm owing to the optimized optical properties of the dual-periodic III-nitride DBRs. Compared with their conventional counterparts, an increased multiplication gain and a reduced breakdown voltage are achieved by using p-type Al0.15Ga0.85N layers with a lower Al content and multiplication layers. These improvements are attributed to the high p-doping efficiency and large hole ionization coefficient.

  1. A process evaluation of the WHiTE Two trial comparing total hip artroplasty with and without dual mobility component in the treatment of displaced intracapsular fractures of the proximal femur

    Science.gov (United States)

    Huxley, C.; Achten, J.; Costa, M. L.; Griffiths, F.

    2016-01-01

    Objectives The annual incidence of hip fracture is 620 000 in the European Union. The cost of this clinical problem has been estimated at 1.75 million disability-adjusted life years lost, equating to 1.4% of the total healthcare burden in established market economies. Recent guidance from The National Institute for Health and Clinical Excellence (NICE) states that research into the clinical and cost effectiveness of total hip arthroplasty (THA) as a treatment for hip fracture is a priority. We asked the question: can a trial investigating THA for hip fracture currently be delivered in the NHS? Methods We performed a contemporaneous process evaluation that provides a context for the interpretation of the findings of WHiTE Two – a randomised study of THA for hip fracture. We developed a mixed methods approach to situate the trial centre within the context of wider United Kingdom clinical practice. We focused on fidelity, implementation, acceptability and feasibility of both the trial processes and interventions to stakeholder groups, such as healthcare providers and patients. Results We have shown that patients are willing to participate in this type of research and that surgeons value being part of a team that has a strong research ethos. However, surgical practice does not currently reflect NICE guidance. Current models of service delivery for hip fractures are unlikely to be able to provide timely total hip arthroplasty for suitable patients. Conclusions Further observational research should be conducted to define the population of interest before future interventional studies are performed. Cite this article: C. Huxley, J. Achten, M. L. Costa, F. Griffiths, X. L. Griffin. A process evaluation of the WHiTE Two trial comparing total hip artroplasty with and without dual mobility component in the treatment of displaced intracapsular fractures of the proximal femur: Can a trial investigating total hip arthroplasty for hip fracture be delivered in the NHS? Bone

  2. VOLTAGE STABILITY ASSESSMENT FOR WIND FARMS INTEGRATION INTO ELECTRICITY GRIDS WITH AND WITHOUT CONSIDERATION OF VOLTAGE DEPENDENT LOADS

    Directory of Open Access Journals (Sweden)

    TOMA R.

    2016-09-01

    Full Text Available The paper presents a comparative study between the effects on voltage stability of the integration of a wind farm into the electricity grid with or without voltage dependent loads in the context of different locations of a synchronous compensator from the grid. The P-V curves are built by using the PowerFactory DigSilent 15.2.2 and a DPL script that implements a simplified form of the Continuation Power Flow method.

  3. A low voltage CMOS low drop-out voltage regulator

    Science.gov (United States)

    Bakr, Salma Ali; Abbasi, Tanvir Ahmad; Abbasi, Mohammas Suhaib; Aldessouky, Mohamed Samir; Abbasi, Mohammad Usaid

    2009-05-01

    A low voltage implementation of a CMOS Low Drop-Out voltage regulator (LDO) is presented. The requirement of low voltage devices is crucial for portable devices that require extensive computations in a low power environment. The LDO is implemented in 90nm generic CMOS technology. It generates a fixed 0.8V from a 2.5V supply which on discharging goes to 1V. The buffer stage used is unity gain configured unbuffered OpAmp with rail-to-rail swing input stage. The simulation result shows that the implemented circuit provides load regulation of 0.004%/mA and line regulation of -11.09mV/V. The LDO provides full load transient response with a settling time of 5.2μs. Further, the dropout voltage is 200mV and the quiescent current through the pass transistor (Iload=0) is 20μA. The total power consumption of this LDO (excluding bandgap reference) is only 80μW.

  4. Implementation of Dynamic Voltage Restorer for Mitigation of Voltage Sag

    Directory of Open Access Journals (Sweden)

    K.Vinod Kumar

    2013-07-01

    Full Text Available Power quality is one of major concerns in the present. It has become important, especially with the introduction of sophisticated devices, whose performance is very sensitive to the quality of power supply. The dynamic voltage restorer (DVR is one of the modern devices used in distribution systems to improve the power quality. In this paper, emergency control in distribution systems is discussed by using the proposed multifunctional DVR control strategy.Also, themultiloop controller using the Posicast and P+Resonant controllers is proposed in order to improve the transient response and eliminate the steady state error in DVR response,respectively.The proposed process is applied to some riots in load voltage effected by induction motors starting, and a three-phase short circuit fault. The three-phase short circuits, and the large induction motors are suddenly started then voltage sags areoccurred.The innovation here is that by using the Multifunctional Dynamic Voltage Restorer, improve the power quality in distribution side. Simulation results show the capability of the DVR to control the emergency conditions of the distribution systems by using MATLAB/Simulink software.

  5. Walkable dual emissions

    National Research Council Canada - National Science Library

    Xu, Hai-Bing; Jiao, Peng-Chong; Kang, Bin; Deng, Jian-Guo; Zhang, Yan

    2013-01-01

    Walkable dual emissions, in which the emission bands of the walker reversibly cross or leave those of the stationary ones depending on temperature and concentration, have been demonstrated in cyclic...

  6. The high voltage homopolar generator

    Science.gov (United States)

    Price, J. H.; Gully, J. H.; Driga, M. D.

    1986-11-01

    System and component design features of proposed high voltage homopolar generator (HVHPG) are described. The system is to have an open circuit voltage of 500 V, a peak output current of 500 kA, 3.25 MJ of stored inertial energy and possess an average magnetic-flux density of 5 T. Stator assembly components are discussed, including the stator, mount structure, hydrostatic bearings, main and motoring brushgears and rotor. Planned operational procedures such as monitoring the rotor to full speed and operation with a superconducting field coil are delineated.

  7. Comparative a numble of monitoring indicator, explore the superiority about Supreme dual-chamber laryngeal mask used for cesarean section anesthesia%Supreme双腔喉罩在剖宫产孕妇全身麻醉中的应用

    Institute of Scientific and Technical Information of China (English)

    房小斌; 姚伟瑜; 李师阳

    2013-01-01

    ,Narcotrend and Apgar scores were observed.Results Before and after the LMA group inserted laryngeal mask HR,MAP no significant change in the performance of Narcotrend value remained at the level of anesthesia,intubation before and after HR,MAP significantly increased performance of Narcotrend values significantly increased,both compared to the obvious statistical difference (P < 0.05).The ventilation indicators of two groups compared to no significant difference (P > 0.05).LMA group cover required intubation time was significantly shorter than the time required for intubation of endotracheal intubation group (P < 0.01).Three groups of patient administration to the fetus at all times is in 5-10 min.Three groups similar to the Apgar score was no significant difference (P > 0.05).Conclusion The dual-chamber laryngeal mask airway for caesarean section anesthesia,fetal Apgar scores,feasibility,and its operation is easy,safe and comfortable anesthesia,compared tracheal intubation has obvious superiority.

  8. Resilient architecture design for voltage variation

    CERN Document Server

    Reddi, Vijay Janapa

    2013-01-01

    Shrinking feature size and diminishing supply voltage are making circuits sensitive to supply voltage fluctuations within the microprocessor, caused by normal workload activity changes. If left unattended, voltage fluctuations can lead to timing violations or even transistor lifetime issues that degrade processor robustness. Mechanisms that learn to tolerate, avoid, and eliminate voltage fluctuations based on program and microarchitectural events can help steer the processor clear of danger, thus enabling tighter voltage margins that improve performance or lower power consumption. We describe

  9. SVPWM Technique with Varying DC-Link Voltage for Common Mode Voltage Reduction in a Matrix Converter and Analytical Estimation of its Output Voltage Distortion

    Science.gov (United States)

    Padhee, Varsha

    Common Mode Voltage (CMV) in any power converter has been the major contributor to premature motor failures, bearing deterioration, shaft voltage build up and electromagnetic interference. Intelligent control methods like Space Vector Pulse Width Modulation (SVPWM) techniques provide immense potential and flexibility to reduce CMV, thereby targeting all the afore mentioned problems. Other solutions like passive filters, shielded cables and EMI filters add to the volume and cost metrics of the entire system. Smart SVPWM techniques therefore, come with a very important advantage of being an economical solution. This thesis discusses a modified space vector technique applied to an Indirect Matrix Converter (IMC) which results in the reduction of common mode voltages and other advanced features. The conventional indirect space vector pulse-width modulation (SVPWM) method of controlling matrix converters involves the usage of two adjacent active vectors and one zero vector for both rectifying and inverting stages of the converter. By suitable selection of space vectors, the rectifying stage of the matrix converter can generate different levels of virtual DC-link voltage. This capability can be exploited for operation of the converter in different ranges of modulation indices for varying machine speeds. This results in lower common mode voltage and improves the harmonic spectrum of the output voltage, without increasing the number of switching transitions as compared to conventional modulation. To summarize it can be said that the responsibility of formulating output voltages with a particular magnitude and frequency has been transferred solely to the rectifying stage of the IMC. Estimation of degree of distortion in the three phase output voltage is another facet discussed in this thesis. An understanding of the SVPWM technique and the switching sequence of the space vectors in detail gives the potential to estimate the RMS value of the switched output voltage of any

  10. Requirement of ultra-high voltage GIS arrester to voltage gradient of metal-oxide varistor

    Institute of Scientific and Technical Information of China (English)

    HE JinLiang; HU Jun; MENG BoWen; ZHANG Bo; ZHU Bin; CHEN ShuiMing; ZENG Rong

    2009-01-01

    The surge arrestor with excellent protection characteristics would decrease the overvoltage level ap-plied on the power apparatus to reduce their insulation levels and manufacturing bottleneck. The ar-restor for the 1000-kV ultra-high voltage ac power transmission system is designed as tank-type structure. The field-circuit combination numerical method combining the three-dimensional finite ele-ment method with circuit is proposed to analyze the potential distribution of GIS arrester. By comparing several design schemes, the most effective method to improve the potential distribution along the varistor column is to increase the voltage gradient of the ZnO varistor. Synthesizing several influential factors, the suitable voltage gradient of ZnO varistor should be controlled to 435 V/mm, and the re-sulted nonuniform degree of the potential distribution along the varistor column inside the GIS arrestor would be controlled smaller than 10%. The result in this paper provides the fundamental technical in-dex for the study of the high voltage gradient ZnO varistors.

  11. Requirement of ultra-high voltage GIS arrester to voltage gradient of metal-oxide varistor

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The surge arrester with excellent protection characteristics would decrease the overvoltage level ap- plied on the power apparatus to reduce their insulation levels and manufacturing bottleneck. The arrester for the 1000-kV ultra-high voltage ac power transmission system is designed as tank-type structure. The field-circuit combination numerical method combining the three-dimensional finite element method with circuit is proposed to analyze the potential distribution of GIS arrester. By comparing several design schemes, the most effective method to improve the potential distribution along the varistor column is to increase the voltage gradient of the ZnO varistor. Synthesizing several influential factors, the suitable voltage gradient of ZnO varistor should be controlled to 435 V/mm, and the resulted nonuniform degree of the potential distribution along the varistor column inside the GIS arrester would be controlled smaller than 10%. The result in this paper provides the fundamental technical index for the study of the high voltage gradient ZnO varistors.

  12. State of charge modeling of lithium-ion batteries using dual exponential functions

    Science.gov (United States)

    Kuo, Ting-Jung; Lee, Kung-Yen; Huang, Chien-Kang; Chen, Jau-Horng; Chiu, Wei-Li; Huang, Chih-Fang; Wu, Shuen-De

    2016-05-01

    A mathematical model is developed by fitting the discharging curve of LiFePO4 batteries and used to investigate the relationship between the state of charge and the closed-circuit voltage. The proposed mathematical model consists of dual exponential terms and a constant term which can fit the characteristics of dual equivalent RC circuits closely, representing a LiFePO4 battery. One exponential term presents the stable discharging behavior and the other one presents the unstable discharging behavior and the constant term presents the cut-off voltage.

  13. DC Characteristics of AlGaN/GaN HEMTs Using a Dual-Gate Structure.

    Science.gov (United States)

    Hong, Sejun; Rana, Abu ul Hassan Sarwar; Heo, Jun-Woo; Kim, Hyun-Seok

    2015-10-01

    Multiple techniques such as fluoride-based plasma treatment, a p-GaN or p-AlGaN gate contact, and a recessed gate structure have been employed to modulate the threshold voltage of AlGaN/GaN-based high-electron-mobility transistors (HEMTs). In this study, we present dual-gate AlGaN/GaN HEMTs grown on a Si substrate, which effectively shift the threshold voltage in the positive direction. Experimental data show that the threshold voltage is shifted from -4.2 V in a conventional single-gate HEMT to -2.8 V in dual-gate HEMTs. It is evident that a second gate helps improve the threshold voltage by reducing the two-dimensional electron gas density in the channel. Furthermore, the maximum drain current, maximum transconductance, and breakdown voltage values of a single-gate device are not significantly different from those of a dual-gate device. For the fabricated single- and dual-gate devices, the values of the maximum drain current are 430 mA/mm and 428 mA/mm, respectively, whereas the values of the maximum transconductance are 83 mS/mm and 75 mS/mm, respectively.

  14. A nanoscale dual-channel trench (DCT) MOSFET for analog/RF applications

    Science.gov (United States)

    Adhikari, Manoj Singh; Singh, Yashvir

    2015-12-01

    In this paper, we propose a dual-channel trench MOSFET (DCT-MOSFET) on SOI for high-frequency small signal analog applications. The gate of device is placed in a trench which creates two n-channels in p-base carrying drain current in parallel. Simultaneous conduction of two-channels provides substantial improvement in performance parameters. Based on two-dimensional simulations, a 60 nm DCT-MOSFET is demonstrated to achieve 92% higher drain current, twofold increase in peak transconductance, 67% rise in transconductance-to-drain current ratio, 47% higher intrinsic voltage gain, 90% improvement in cut-off frequency and 2.1 times higher maximum oscillation frequency as compared to the conventional MOSFET.

  15. A new ROIC with high-voltage protection circuit of HgCdTe e-APD FPA for passive and active imaging

    Science.gov (United States)

    Chen, Guoqiang; Zhang, Junling; Wang, Pan; Zhou, Jie; Gao, Lei; Ding, Ruijun

    2012-12-01

    HgCdTe electrons initiated avalanche photodiodes (e-APDs) in linear multiplication mode can be used for high speed applications such as active imaging. A readout integrated circuit of e-APD FPA is designed for dual mode passive/active imaging system. Unit cell circuit architecture of ROIC includes a high voltage protection module, a Sample-Hold circuit module, a comparator, output driver stage and a integrator module which includes a amplifier and three capacitors. Generally, APD FPA works at reversed bias such as 5V-15V in active imaging mode, and pixels' dark currents increase exponentially as the reverse-bias voltage is increased. Some cells of ROIC may be short to high voltage because of avalanche breakdown of diodes. If there is no protection circuit, the whole ROIC would be burnt out. Thus a protection circuit module introduced in every ROIC cell circuit is necessary to make sure the rest units of ROIC can still work. Conventional 5V CMOS process is applied to implement the high voltage protection with the small area other than LDMOS in high voltage BCD process in the limited 100μm×100μm pitch area. In integrator module, three integration capacitors are included in the ROIC to provide switchable well capacity. One of them can be shared in two modes in order to save area. Constraints such as pixel area and power lead us design toward a simple one-stage cascade operational transconductance amplifier (OTA) as pre-amplifier which can avoid potential instability caused by inaccuracy of MOSFET Model at 77K.

  16. Zero-voltage switching technique in dc/dc converters

    Science.gov (United States)

    Liu, Kwang-Hwa; Lee, Fred C. Y.

    1990-07-01

    A novel resonant switch operating under the principle of zero-voltage switching is presented. In contrast to the zero-current switching, this technique eliminates the switching loss and dv/dt noise due to the discharging of MOSFET junction capacitances and the reverse recovery of diodes, and enables the converters to operate at high frequencies. A dc analysis of the converter is carried out. The duality relationship between the zero-current switching technique and the zero-voltage switching technique is derived. The two techniques are compared using an example showing the duality between a current-mode quasi-resonant Buck converter and a voltage-mode quasi-resonant boost converter. A 5-MHz 50 V to 5 V flyback converter employing the zero-voltage switching technique has been implemented. The circuit contains the smallest number of components possible, and yet maintains high efficiency at high switching frequency.

  17. The transfer voltage standard for calibration outside of a laboratory

    Directory of Open Access Journals (Sweden)

    Urekar Marjan

    2017-01-01

    Full Text Available The transfer voltage standard is designed for transferring the analog voltage from a calibrator to the process control workstation for multi-electrode electrolysis process in a plating plant. Transfer voltage standard is based on polypropylene capacitors and operational amplifiers with tera-ohm range input resistance needed for capacitor self-discharging effect cancellation. Dielectric absorption effect is described. An instrument for comparison of reference and control voltages is devised, based on precise window comparator. Detailed description of the main task is given, including constraints, theoretical and practical solutions. Procedure for usage of the standard outside of a laboratory conditions is explained. Comparison of expected and realized standard characteristics is given. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR-32019

  18. High-voltage air-core pulse transformers

    Energy Technology Data Exchange (ETDEWEB)

    Rohwein, G. J.

    1981-01-01

    General types of air core pulse transformers designed for high voltage pulse generation and energy transfer applications are discussed with special emphasis on pulse charging systems which operate up to the multi-megavolt range. The design, operation, dielectric materials, and performance are described. It is concluded that high voltage air core pulse transformers are best suited to applications outside the normal ranges of conventional magnetic core transformers. In general these include charge transfer at high power levels and fast pulse generation with comparatively low energy. When properly designed and constructed, they are capable of delivering high energy transfer efficiency and have demonstrated superior high voltage endurance. The principal disadvantage of high voltage air core transformers is that they are not generally available from commercial sources. Consequently, the potential user must become thoroughly familiar with all aspects of design, fabrication and system application before he can produce a high performance transformer system. (LCL)

  19. Microwave generation enhancement of X-band CRBWO by use of coaxial dual annular cathodes

    OpenAIRE

    Yan Teng; Jun Sun; Changhua Chen; Hao Shao

    2013-01-01

    This paper presents an approach that greatly enhances both the output power and the conversion efficiency of the coaxial relativistic backward wave oscillator (CRBWO) by using coaxial dual annular cathodes, which increases the diode current rather than the diode voltage. The reasons for the maladjustment of CRBWO under a high diode voltage are analyzed theoretically. It is found that by optimization of the diode structure, the shielding effect of the space charge of the outer beams on the inn...

  20. Microwave generation enhancement of X-band CRBWO by use of coaxial dual annular cathodes

    OpenAIRE

    Yan Teng; Jun Sun; Changhua Chen; Hao Shao

    2013-01-01

    This paper presents an approach that greatly enhances both the output power and the conversion efficiency of the coaxial relativistic backward wave oscillator (CRBWO) by using coaxial dual annular cathodes, which increases the diode current rather than the diode voltage. The reasons for the maladjustment of CRBWO under a high diode voltage are analyzed theoretically. It is found that by optimization of the diode structure, the shielding effect of the space charge of the outer beams on the inn...

  1. VOLTAGE REGULATORS OF SYNCHRONOUS GENERATORS

    Directory of Open Access Journals (Sweden)

    Grigorash O. V.

    2015-06-01

    Full Text Available Synchronous generators are the primary source of electrical power autonomous electrosupply systems, including backup systems. They are also used in a structure of rotating electricity converters and are widely used in renewable energy as part of wind power plants of small, mini and micro hydroelectric plants. Increasing the speed and the accuracy of the system of the voltage regulation of synchronous generators is possible due to the development of combined systems containing more stabilizers. The article illustrates the functional schemes of circuit voltage stabilizers and frequency synchronous generators (with electromagnetic excitation and permanent magnet excitation and describes the features of their work, including two and three-aggregate rotating converters of electricity used in uninterruptible power supply systems. To improve the technical characteristics of the system of stabilization we have proposed functional solutions for stabilizers of synchronous generators made on the base of direct frequency converters and using a transformer with a rotating magnetic field. To improve the reliability of and to improve the operational characteristics of the autonomous independent sources of electricity we suggest creating the main functional blocks and the elements of the stabilization system in a modular way. The functional circuit solutions of voltage regulators of synchronous generators and the characteristics of their work considered in the article, are able to improve the efficiency of pre-design work in the development of new technical solutions for stabilizing the voltage and the frequency in synchronous generators of electrosupply autonomous systems

  2. Frequency-controlled voltage regulator

    Science.gov (United States)

    Mclyman, W. T.

    1980-01-01

    Converting input ac to higher frequency reduce size and weight and makes possible unique kind of regulation. Since conversion frequency is above range of human hearing, supply generated on audible noise. It also exploits highfrequency conversion features to regulate its output voltage in novel way. Circuit is inherently short-circuit proof.

  3. Dual diagnosis and suicide risk in a Spanish outpatient sample.

    Science.gov (United States)

    Szerman, Nestor; Lopez-Castroman, Jorge; Arias, Francisco; Morant, Consuelo; Babín, Francisco; Mesías, Beatriz; Basurte, Ignacio; Vega, Pablo; Baca-García, Enrique

    2012-03-01

    The present study compares dual-diagnosis patients with other groups of psychiatric patients to determine the differential characteristics in suicide risk and other clinical variables between them. During 2008 in Madrid, 837 outpatients were evaluated in addiction and mental health services. Three comparison groups were created according to current diagnosis: (i) dual patients, (ii) patients with substance use disorders but no other mental disorders, and (iii) patients with mental disorders but no substance use disorders. A multinomial logistic regression model was built to explore the risk associated with dual diagnosis. Criteria for dual diagnosis were met at the time of the study by 440 patients (52.6%). Dual patients showed several demographic and clinical differences and a higher risk for suicide than the other two comparison groups. Further research is needed to define suicide preventive strategies for dual patients.

  4. Performance Evaluation of Three Different Inverter Configurations of DVR for Mitigation of Voltage Events

    Directory of Open Access Journals (Sweden)

    Miska Prasad

    2016-12-01

    Full Text Available The voltage events namely voltage sags and voltage swells represent the most common, frequent and important power quality events in today’s power system. Dynamic voltage restorer (DVR is one of the key components used to mitigate the supply voltage quality disturbances in terms of voltage sags and swells in the distribution system. It consists of an energy storage unit, a voltage source inverter, a filter, a coupling transformer and the control system. This paper presents three different inverter configurations of dynamic voltage restorer (DVR for mitigation of voltage events such as voltage sags and swells with sudden addition or removal of the nonlinear load. These three configurations are voltage source inverter based DVR (VSI-DVR, current source inverter based DVR (CSI-DVR and impedance or Z-source inverter based DVR (ZSI-DVR. The d-q control technique is used to control the operation of the DVR. The response of ZSI-DVR for mitigation of voltage sags and swells are investigated and compared with VSI-DVR and CSI-DVR using MATLAB/SIMULINK environment.

  5. Kirchhoff voltage law corrected for radiating circuits

    CERN Document Server

    Lara, Vitor

    2014-01-01

    When a circular loop composed by a RLC is put to oscillate, the oscillation will eventually vanish in an exponentially decaying current, even considering superconducting wires, due to the emission of electric and magnetic dipole radiation. In this work we propose a modification on the Kirchhoff voltage law by adding the radiative contributions to the energy loss as an effective resistance, whose value is relatively small when compared to typical resistance value, but fundamental to describe correctly real circuits. We have also analysed the change in the pattern of the radiation spectra emitted by the circuit as we vary both the effective and electrical resistance.

  6. Low pull-in voltage electrostatic MEMS switch using liquid dielectric

    KAUST Repository

    Zidan, Mohammed A.

    2014-08-01

    In this paper, we present an electrostatic MEMS switch with liquids as dielectric to reduce the actuation voltage. The concept is verified by simulating a lateral dual gate switch, where the required pull-in voltage is reduced by more than 8 times after using water as a dielectric, to become as low as 5.36V. The proposed switch is simulated using COMSOL multiphysics using various liquid volumes to study their effect on the switching performance. Finally, we propose the usage of the lateral switch as a single switch XOR logic gate.

  7. Dual-source cardiac computed tomography angiography (CCTA) in the follow-up of cardiac transplant: comparison of image quality and radiation dose using three different imaging protocols

    Energy Technology Data Exchange (ETDEWEB)

    Beitzke, D.; Berger-Kulemann, V.; Unterhumer, S.; Loewe, C.; Wolf, F. [Medical University Vienna, Department of Biomedical Imaging and Image Guided Therapy, Division of Cardiovascular and Interventional Radiology, Vienna (Austria); Schoepf, V. [Medical University Vienna, Department of Biomedical Imaging and Image Guided Therapy, Division of Neuroradiology and Musculoskeletal Radiology, Vienna (Austria); Spitzer, E. [Bern University Hospital, Department of Cardiology, Bern (Switzerland); Feuchtner, G.M. [Innsbruck Medical University, Department of Radiology II, Innsbruck (Austria); Gyoengyoesi, M. [Medical University Vienna, Department of Cardiology, Vienna (Austria); Uyanik-Uenal, K.; Zuckermann, A. [Medical University Vienna, Department of Cardiac Surgery, Vienna (Austria)

    2015-08-15

    To prospectively evaluate image quality (IQ) and radiation dose of dual-source cardiac computed tomography (CCTA) using different imaging protocols. CCTA was performed in 150 patients using the retrospective ECG-gated spiral technique (rECG) the prospective ECG-gated technique (pECG), or the prospective ECG-gated technique with systolic imaging and automated tube voltage selection (pECGsys). IQ was rated using a 16-segment coronary artery model. Techniques were compared for overall IQ, IQ of the large and the small coronary artery segments. Effective dose was used for comparison of radiation dose. Overall IQ and IQ of the large segments showed no differences between the groups. IQ analysis of the small segments showed lowered IQ in pECGsys compared to rECG (p = 0.02), but not to pECG (p = 0.6). Effective dose did not differ significantly between rECG and pECG (p = 0.13), but was significantly lower for pECGsys (p < 0.001 vs. rECG and pECG). Radiation dose of dual-source CCTA in heart transplant recipients is significantly reduced by using prospective systolic scanning and automated tube voltage selection, while overall IQ and IQ of the large coronary segments are maintained. IQ appears to be lower compared to retrospective techniques with regard to small coronary segments. (orig.)

  8. Comparative study of Cu(In,Ga)Se{sub 2}/(PVD)In{sub 2}S{sub 3} and Cu(In,Ga)Se{sub 2}/(CBD)CdS heterojunction based solar cells by admittance spectroscopy, current-voltage and spectral response measurements

    Energy Technology Data Exchange (ETDEWEB)

    Darga, A. [Laboratoire de Genie Electrique de Paris, CNRS UMR8507, SUPELEC, UPMC Univ Paris 06, Univ Paris-Sud, 11 rue Joliot-Curie, Plateau de Moulon, F-91192 Gif-sur-Yvette Cedex (France)], E-mail: arouna.darga@lgep.supelec.fr; Mencaraglia, D.; Djebbour, Z.; Dubois, A. Migan; Chouffot, R.; Serhan, J. [Laboratoire de Genie Electrique de Paris, CNRS UMR8507, SUPELEC, UPMC Univ Paris 06, Univ Paris-Sud, 11 rue Joliot-Curie, Plateau de Moulon, F-91192 Gif-sur-Yvette Cedex (France); Couzinie-Devy, F.; Barreau, N.; Kessler, J. [Institut des Materiaux Jean Rouxel (IMN)-UMR 6502, Universite de Nantes, CNRS, 2 rue de la Houssiniere, BP 32229, 44322 Nantes cedex 3 (France)

    2009-02-02

    Co-evaporated Cu(In,Ga)Se{sub 2} (CIGSe) based solar cells with Physical Vapour Deposited (PVD) Indium Sulphide (In{sub 2}S{sub 3}) as buffer layer have been studied by admittance spectroscopy and current-voltage characteristics measurements. The results have been compared to those obtained with a reference CBD-CdS/CIGSe device. In darkness, the PVD-In{sub 2}S{sub 3} buffer layer devices exhibit higher densities of trapping defects and low values of shunt resistance. However, under illumination we have observed an important improvement of the In{sub 2}S{sub 3}/CIGSe electronic transport properties. This behavior seems to be linked to the presence of a metastable defect with activation energy of 0.3 eV.

  9. Power flow control and voltage stability limit: regulating transformer versus UPFC

    Energy Technology Data Exchange (ETDEWEB)

    Haque, M.H. [Nanyang Technological Univ., Center for Advanced Power Electronics, Nanyang (Singapore)

    2004-05-01

    Power flow through an AC transmission line can be controlled by injecting an adjustable compensating voltage in series with the line. This paper evaluates and compares the power flow control ranges of a simple system obtained by injecting an adjustable series compensating voltage produced by a regulating transformer and unified power flow controller. The static voltage stability limits of the system with a regulating transformer and unified power flow controller are also determined and compared. In evaluating the power flow control ranges and voltage stability limits, the transmission line of the system is modelled in four different ways. The results obtained for various line models are also compared. (Author)

  10. On quantum equivalence of dual $\\sigma$ models $SL(3)$ examples

    CERN Document Server

    Horváth, Z; Palla, L

    1996-01-01

    The equivalence of several $SL(3)$ sigma models and their special Abelian duals is investigated in the two loop order of perturbation theory. The investigation is based on extracting and comparing various $\\beta$ functions of the original and dual models. The role of the discrete global symmetries is emphasized.

  11. On quantum equivalence of dual sigma models: SL(3) examples

    Energy Technology Data Exchange (ETDEWEB)

    Horvath, Z. [Lorand Eoetvoes Univ., Budapest (Hungary). Inst. for Theoretical Physics; Karp, R.L. [Lorand Eoetvoes Univ., Budapest (Hungary). Inst. for Theoretical Physics; Palla, L. [Lorand Eoetvoes Univ., Budapest (Hungary). Inst. for Theoretical Physics

    1997-04-14

    The equivalence of several SL(3) sigma models and their special Abelian duals is investigated in two-loop order of perturbation theory. The investigation is based on extracting and comparing various {beta}-functions of the original and dual models. The role of discrete global symmetries is emphasized. (orig.).

  12. A 3.16-7 GHz transformer-based dual-band CMOS VCO

    Science.gov (United States)

    Zhu, Li; Zhigong, Wang; Zhiqun, Li; Qin, Li; Faen, Liu

    2015-03-01

    A dual-band, wide tuning range voltage-controlled oscillator that uses transformer-based fourth-order (LC) resonator with a compact common-centric layout is presented. Compared with the traditional wide band (VCO), it can double frequency tuning range without degrading phase noise performance. The relationship between the coupling coefficient of the transformer, selection of frequency bands, and the quality factor at each band is investigated. The transformer used in the resonator is a circular asymmetric concentric topology. Compared with conventional octagon spirals, the proposed circular asymmetric concentric transformer results in a higher quality-factor, and hence a lower oscillator phase noise. The VCO is designed and fabricated in a 0.18-μm CMOS technology and has 75% wide tuning range of 3.16-7.01 GHz. Depending on the oscillation frequency, the VCO current consumption is adjusted from 4.9 to 6.3 mA. The measured phase noises at 1 MHz offset from carrier frequencies of 3.1, 4.5, 5.1, and 6.6 GHz are -122.5, -113.3, -110.1, and -116.8 dBc/Hz, respectively. The chip area, including the pads, is 1.2 × 0.62 mm2 and the supply voltage is 1.8 V. Project supported by the National High Technology Research and Development Program of China (No. 2011AA10305) and the National Natural Science Foundation of China (No. 60901012).

  13. Theoretical study of the dual harmonic system and its application on the CSNS/RCS

    CERN Document Server

    Yuan, Yao-Shuo; Xu, Shou-Yan; Yuan, Yue; Wang, Sheng

    2015-01-01

    The dual harmonic system has been widely used in high intensity proton synchrotrons to suppress the space charge effect, as well as reduce the beam loss. To investigate the longitudinal beam dynamics in the dual rf system, the potential well, the sub-buckets in the bunch and the multi-solutions of the phase equation have been studied theoretically. Based on these theoretical studis, the optimization of bunching factor and rf voltage waveform are made for the dual harmonic rf system in the upgrade phase of the CSNS/RCS. In the optimization process, the simulation with space charge effect is done by using a newly developed code C-SCSIM.

  14. Voltage dips generated by user`s equipment

    Energy Technology Data Exchange (ETDEWEB)

    Ruest, D. [Hydro-Quebec, Varennes, PQ (Canada)

    1997-12-01

    A three year project was conducted by the Canadian Electricity Association (CEA) and Hydro-Quebec to measure voltage dips and short interruptions at 36 industrial sites across Canada (26 in Quebec, 3 in Nova Scotia, 2 in Ontario, and 3 in Manitoba). These disturbances are among the most harmful for power supply networks. This project was initiated in response to a request by the Union Internationale d`Electrothermie`s (UIE). The UIE is an international standards organizations which has set limits for voltage dips and short interruptions for utilities. In this study, an equivalent of 6.45 site-years of data was acquired and the results were compared against other surveys. Although the results could not be compared against other measurements because of different isokeraunic zones and network designs, they were, nevertheless, comparable. Other disturbances that were also measured included phase variation, frequency variation, and voltage swells. tabs., figs.

  15. Over-voltage protection system and method

    Energy Technology Data Exchange (ETDEWEB)

    Chi, Song; Dong, Dong; Lai, Rixin

    2017-05-02

    An over-voltage protection system includes an electronic valve connected across two terminals of a circuit and an over-voltage detection circuit connected across one of the plurality of semiconductor devices for detecting an over-voltage across the circuit. The electronic valve includes a plurality of semiconductor devices connected in series. The over-voltage detection circuit includes a voltage divider circuit connected to a break-over diode in a way to provide a representative low voltage to the break-over diode and an optocoupler configured to receive a current from the break-over diode when the representative low voltage exceeds a threshold voltage of the break-over diode indicating an over-voltage condition. The representative low voltage provided to the break-over diode represents a voltage across the one semiconductor device. A plurality of self-powered gate drive circuits are connected to the plurality of semiconductor devices, wherein the plurality of self-powered gate drive circuits receive over-voltage triggering pulses from the optocoupler during the over-voltage condition and switch on the plurality of semiconductor devices to bypass the circuit.

  16. Analysis of the Light Propagation Model of the Optical Voltage Sensor for Suppressing Unreciprocal Errors.

    Science.gov (United States)

    Li, Hui; Fu, Zhida; Liu, Liying; Lin, Zhili; Deng, Wei; Feng, Lishuang

    2017-01-03

    An improved temperature-insensitive optical voltage sensor (OVS) with a reciprocal dual-crystal sensing method is proposed. The inducing principle of OVS reciprocity degradation is expounded by taking the different temperature fields of two crystals and the axis-errors of optical components into consideration. The key parameters pertaining to the system reciprocity degeneration in the dual-crystal sensing unit are investigated in order to optimize the optical sensing model based on the Maxwell's electromagnetic theory. The influencing principle of axis-angle errors on the system nonlinearity in the Pockels phase transfer unit is analyzed. Moreover, a novel axis-angle compensation method is proposed to improve the OVS measurement precision according to the simulation results. The experiment results show that the measurement precision of OVS is superior to ±0.2% in the temperature range from -40 °C to +60 °C, which demonstrates the excellent temperature stability of the designed voltage sensing system.

  17. Design and Control of a Dynamic Voltage Restorer

    DEFF Research Database (Denmark)

    Nielsen, John Godsk

    . The advantages and disadvantages are treated by inserting the DVR in either the medium voltage distribution system or in the low voltage distribution system. Different topologies for a DVR are investigated on a converter and system level and the protection issues are treated. The design of a DVR is treated...... and two prototype DVRs are designed and specified. The first DVR is a low voltage DVR (LV-DVR) rated for 10 kVA for insertion in a 400 V low voltage grid and the second DVR is a high voltage DVR (HV-DVR) rated for 200 kVA for insertion in a 10 kV medium voltage distribution system. The control issues...... in order to aid the design process and perform simulations on a DVR. The simulations have been compared with measurements in order to be able to test the validity of the models. A good agreement have been found between simulations and measurements, which indicates that the system is sufficiently modelled...

  18. Study of the breakdown voltage of SiPMs

    CERN Document Server

    Chmill, V; Klanner, R; Nitschke, M; Schwandt, J

    2016-01-01

    The breakdown behaviour of SiPMs (Silicon PhotoMultiplier) with pixel sizes of 15$\\times $15, 25$\\times $25, 50$\\times $50, and 100$\\times $100 $\\mu $m$^2$, manufactured by KETEK, has been investigated. From the current-voltage characteristics measured with and without illumination by LED light of 470 nm wavelength, the current-breakdown voltage, $V_I$, and from linear fits of the voltage dependence of the SiPM gain, measured by recording pulse-area spectra, the gain-breakdown voltage, $V_G$, have been obtained. The voltage dependence of the Geiger-breakdown probability was determined from the fraction of zero photoelectron events with LED illumination. By comparing the results to a model calculation, the photodetection-breakdown voltage, $V_{PD}$, has been determined. Within experimental uncertainties, $V_I$ and $V_{PD}$ are equal and independent of pixel size. For $V_G$, a dependence on pixel size is observed. The difference $V_I - V_G$ is about 1 V for the SiPM with 15 $\\mu $m pixels, decreases with pixel ...

  19. Study of the breakdown voltage of SiPMs

    Science.gov (United States)

    Chmill, V.; Garutti, E.; Klanner, R.; Nitschke, M.; Schwandt, J.

    2017-02-01

    The breakdown behaviour of SiPMs (Silicon PhotoMultiplier) with pixel sizes of 15 × 15 , 25 × 25 , 50 × 50, and 100 × 100 μm2, manufactured by KETEK, has been investigated. From the current-voltage characteristics measured with and without illumination by LED light of 470 nm wavelength, the current-breakdown voltage, VI, and from linear fits of the voltage dependence of the SiPM gain, measured by recording pulse-area spectra, the gain-breakdown voltage, VG, have been obtained. The voltage dependence of the Geiger-breakdown probability was determined from the fraction of zero photoelectron events with LED illumination. By comparing the results to a model calculation, the photodetection-breakdown voltage, VPD, has been determined. Within experimental uncertainties, VI and VPD are equal and independent of pixel size. For VG, a dependence on pixel size is observed. The difference VI -VG is about 1 V for the SiPM with 15 μm pixels, decreases with pixel size and is compatible with zero for the SiPM with 100 μm pixels.

  20. Optimization of power systems with voltage security constraints

    Science.gov (United States)

    Rosehart, William Daniel

    As open access market principles are applied to power systems, significant changes in their operation and control are occurring. In the new marketplace, power systems are operating under higher loading conditions as market influences demand greater attention to operating cost versus stability margins. Since stability continues to be a basic requirement in the operation of any power system, new tools are being considered to analyze the effect of stability on the operating cost of the system, so that system stability can be incorporated into the costs of operating the system. In this thesis, new optimal power flow (OPF) formulations are proposed based on multi-objective methodologies to optimize active and reactive power dispatch while maximizing voltage security in power systems. The effects of minimizing operating costs, minimizing reactive power generation and/or maximizing voltage stability margins are analyzed. Results obtained using the proposed Voltage Stability Constrained OPF formulations are compared and analyzed to suggest possible ways of costing voltage security in power systems. When considering voltage stability margins the importance of system modeling becomes critical, since it has been demonstrated, based on bifurcation analysis, that modeling can have a significant effect of the behavior of power systems, especially at high loading levels. Therefore, this thesis also examines the effects of detailed generator models and several exponential load models. Furthermore, because of its influence on voltage stability, a Static Var Compensator model is also incorporated into the optimization problems.

  1. Quantitative analysis of irreversibilities causes voltage drop in fuel cell (simulation and modeling)

    Energy Technology Data Exchange (ETDEWEB)

    Ghadamian, Hossein [Azad Univ., Dept. of Energy Engineering, Tehran (Iran); Saboohi, Yadolah [Sharif Energy Research Inst. (SERI), Tehran (Iran)

    2004-11-30

    Power level of a fuel cell depends on its operating condition, which is product of voltage and current-density the highest level of voltage is identified as reversible open circuit voltage (ROCV), which represents an ideal theoretical case [J. Larmin, A. Dicks, Fuel Cell System Explained, Wiley, 2000 (ISBN)]. Compared to that is ideal operating voltage which is usually characterized as open circuit voltage (OCV). An evaluation of deviation of operating voltage level from ideal operational case may provide information on the extent of improving efficiency and energy efficiency of a fuel cell. Therefore, quantification of operation deviation from OCV is the main point that is discussed in the present paper. The analysis procedure of voltage drop is based on step-by-step review of voltage drops over activation, internal currents (fuel-cross-over), Ohmic and mass-transport or concentration losses. Accumulated total voltage drops would be estimated as a sum of aforementioned losses. The accumulated voltage drops will then be reduced from OCV to obtain the operating voltage level. The above numerical analysis has been applied to identify the extents of voltage drop. The possible reducing variables in voltage drops reviewed and concluded that the activation loss has considerable impact on total voltage drops and it explains the most part of total losses. It is also found that the following correspondence parameters cause decrease in voltage drops: 1. Temperature increasing; 2. Pressure increasing; 3. Hydrogen or oxygen concentration increasing; 4. Electrode effective surface increasing; 5. Electrode and electrolyte, conductivity modification; 6. Electrolyte thickness reducing up to possible limitation; 7. Connection modification. (Author)

  2. Demonstration and evaluation of dual-fuel technology; Demonstration och utvaerdering av dual-fuel-tekniken

    Energy Technology Data Exchange (ETDEWEB)

    Staalhammar, Per; Erlandsson, Lennart; Willner, Kristina (AVL MTC Motortestcenter AB (Sweden)); Johannesson, Staffan (Ecoplan AB (Sweden))

    2011-06-15

    There is an increased interest for Dual Fuel (methane-Diesel) applications in Sweden since this technology is seen as one of the more interesting options for a fast and cost effective introduction of biomethane as fuel for HD engines. The Dual Fuel technology has been used for many years, mainly for stationary purpose (generators, pumps and ships) while the Spark Ignited (SI) 'Otto' technology has been used for trucks and busses. One obstacle for introducing Dual Fuel technology for busses and trucks is the EU legislation that don't allow for HD on road certification of Dual Fuel applications. Challenges with the Dual Fuel technology is to develop cost effective applications that is capable of reaching low emissions (especially CH{sub 4} and NO{sub x}) in combination with high Diesel replacement in the test cycles used for on road applications. AVL MTC Motortestcenter AB (hereinafter called AVL) has on commission by SGC (Swedish Gas technical Centre) carried out this project with the objectives to analyze the Dual Fuel (Diesel-methane) technology with focus on emissions, fuel consumption and technical challenges. One important part of this project was to carry out emission tests on selected Dual Fuel applications in Sweden and to compile experiences from existing Dual Fuel technology. This report also summarizes other commonly used technologies for methane engines and compares the Dual Fuel with conventional Diesel and Otto technologies. The major challenges with Dual Fuel applications for on road vehicles will be to develop robust and cost effective solutions that meet the emission legislations (with aged catalysts) and to increase the Diesel replacement to achieve reasonable reduction of green house gases (GHG). This is especially important when biomethane is available as fuel but not Bio-Diesel. It will probably be possible to reach EURO V emission limits with advanced Dual Fuel systems but none of the tested systems reached EURO V emission levels

  3. Homopolar motor with dual rotors

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, John S. (Oak Ridge, TN)

    1998-01-01

    A homopolar motor (10) has a field rotor (15) mounted on a frame (11) for rotation in a first rotational direction and for producing an electromagnetic field, and an armature rotor (17) mounted for rotation on said frame (11) within said electromagnetic field and in a second rotational direction counter to said first rotational direction of said field rotor (15). The two rotors (15, 17) are coupled through a 1:1 gearing mechanism (19), so as to travel at the same speed but in opposite directions. This doubles the output voltage and output power, as compared to a motor in which only the armature is rotated. Several embodiments are disclosed.

  4. Homopolar motor with dual rotors

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, J.S.

    1998-12-01

    A homopolar motor has a field rotor mounted on a frame for rotation in a first rotational direction and for producing an electromagnetic field, and an armature rotor mounted for rotation on said frame within said electromagnetic field and in a second rotational direction counter to said first rotational direction of said field rotor. The two rotors are coupled through a 1:1 gearing mechanism, so as to travel at the same speed but in opposite directions. This doubles the output voltage and output power, as compared to a motor in which only the armature is rotated. Several embodiments are disclosed. 7 figs.

  5. Cerebral artery evaluation of dual energy CT angiography with dual source CT

    Institute of Scientific and Technical Information of China (English)

    MA Rui; LIU Cheng; DENG Kai; SONG Shao-juan; WANG Dao-ping; HUANG Ling

    2010-01-01

    Background Conventional computed tomography angiography (CTA) is time consuming, user-dependent and has poor image quality in skull base region. This study assessed the feasibility of a new method, dual energy CTA for depicting the cerebral artery.Methods Phantom scan was done with head CTA sequences on dual source CT and 64 spiral CT for radiation dose calculation. Dual energy CTA was done with dual source CT on 36 patients who were suspected of having cerebral vascular disease. Three series axial images in 0.75 mm thick, 0.4 mm increment were acquired, which were named with 80 kV, 140 kV and merged images; 80 kV and 140 kV images were transferred into dual energy software, and maximum intensity projection (MIP) image was generated quickly by dual energy bone remove (DEBR group); merged images were transferred into In Space software to acquire MIP image through manual conventional bone remove (CoBR group). Post processing time and reading time were compared. Image qualities of the two groups were compared, mainly focusing on skull base segments of internal carotid artery and bone subtraction. ANOVA and SNK tests were applied for radiation dose comparison. Student's t test and Wilcoxon rank sum test were applied for assessing differences between data for significance. Cohen's kappa was used for interobserver agreement. Results Radiation dose of phantom scan showed dual energy CTA was between digital bone subtraction and conventional CTA. The post processing time and reading time were much shorter in DEBR than CoBR, and image quality in skull base was much higher in DEBR than CoBR (P0.5). Interobserver agreement for all vessel segments was excellent (kappa=0.97). Conclusions Dual energy CTA is a reliable, new modality for depicting cerebral artery, overcoming the limitation of conventional CTA in the skull base region. It can save much time in post processing and reading than conventional CTA.

  6. Advances in high voltage engineering

    CERN Document Server

    Haddad, A

    2005-01-01

    This book addresses the very latest research and development issues in high voltage technology and is intended as a reference source for researchers and students in the field, specifically covering developments throughout the past decade. This unique blend of expert authors and comprehensive subject coverage means that this book is ideally suited as a reference source for engineers and academics in the field for years to come.

  7. High Voltage Pulse Testing Survey.

    Science.gov (United States)

    1985-10-01

    Cryogenic 23 E. Liquids 26 F. Solids 28 1. Polyethylene 28 2. Cross-Linked Polyethylene ( XLPE ) 29 3. Polyimide and Polyvenylchloride (PVC) 31 VI Benefits 35 A...Strength of XLPE Cables 29 vii * 4" I PROGRAM OBJECTIVES The Pulse Test Survey summarizes government, industry, and technical reports on high voltage pulse...system of silicone oil on a XLPE (cross-linked polyethylene) spacer tends to lower the impulse breakdown by approximately 10 percent. The negative impulse

  8. TRANSISTOR HIGH VOLTAGE POWER SUPPLY

    Science.gov (United States)

    Driver, G.E.

    1958-07-15

    High voltage, direct current power supplies are described for use with battery powered nuclear detection equipment. The particular advantages of the power supply described, are increased efficiency and reduced size and welght brought about by the use of transistors in the circuit. An important feature resides tn the employment of a pair of transistors in an alternatefiring oscillator circuit having a coupling transformer and other circuit components which are used for interconnecting the various electrodes of the transistors.

  9. Dual-stream accounts bridge the gap between monkey audition and human language processing. Comment on "Towards a Computational Comparative Neuroprimatology: Framing the language-ready brain" by Michael Arbib

    Science.gov (United States)

    Garrod, Simon; Pickering, Martin J.

    2016-03-01

    Over the last few years there has been a resurgence of interest in dual-stream dorsal-ventral accounts of language processing [4]. This has led to recent attempts to bridge the gap between the neurobiology of primate audition and human language processing with the dorsal auditory stream assumed to underlie time-dependent (and syntactic) processing and the ventral to underlie some form of time-independent (and semantic) analysis of the auditory input [3,10]. Michael Arbib [1] considers these developments in relation to his earlier Mirror System Hypothesis about the origins of human language processing [11].

  10. Comparison of Output Current Ripple in Single and Dual Three-Phase Inverters for Electric Vehicle Motor Drives

    Directory of Open Access Journals (Sweden)

    Jelena Loncarski

    2015-04-01

    Full Text Available The standard solution for the traction system in battery powered electric vehicles (EVs is a two-level (2L inverter feeding a three-phase motor. A simple and effective way to achieve a three-level (3L inverter in battery-supplied electric vehicles consists of using two standard three-phase 2L inverters with the open-end winding connection of standard three-phase ac motors. The 3L inverter solution can be usefully adopted in EVs since it combines several benefits such as current ripple reduction, increment of phase motor voltage with limited voltage ratings of the two battery banks, improvement in system reliability, etc. The reduction in current ripple amplitude is particularly relevant since it is a source of electromagnetic interference and audio noise from the inverter-motor power connection cables and from the motor itself. By increasing the inverter switching frequency the ripple amplitude is reduced, but the drive efficiency decreases due to the proportionally increased switching losses. In this paper the peak-to-peak ripple amplitude of the dual-2L inverter is evaluated and compared with the corresponding ripple of the single-2L inverter, considering the same voltage and power motor ratings. The ripple analysis is carried out as a function of the modulation index to cover the whole modulation range of the inverter, and the theoretical results are verified with experimental tests carried out by an inverter-motor drive prototype.

  11. Low voltage electron beam accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Ochi, Masafumi [Iwasaki Electric Co., Ltd., Tokyo (Japan)

    2003-02-01

    Widely used electron accelerators in industries are the electron beams with acceleration voltage at 300 kV or less. The typical examples are shown on manufactures in Japan, equipment configuration, operation, determination of process parameters, and basic maintenance requirement of the electron beam processors. New electron beam processors with acceleration voltage around 100 kV were introduced maintaining the relatively high dose speed capability of around 10,000 kGy x mpm at production by ESI (Energy Science Inc. USA, Iwasaki Electric Group). The application field like printing and coating for packaging requires treating thickness of 30 micron or less. It does not require high voltage over 110 kV. Also recently developed is a miniature bulb type electron beam tube with energy less than 60 kV. The new application area for this new electron beam tube is being searched. The drive force of this technology to spread in the industries would be further development of new application, process and market as well as the price reduction of the equipment, upon which further acknowledgement and acceptance of the technology to societies and industries would entirely depend. (Y. Tanaka)

  12. Dual phase evolution

    CERN Document Server

    Green, David G; Abbass, Hussein A

    2014-01-01

    This book explains how dual phase evolution operates in all these settings and provides a detailed treatment of the subject. The authors discuss the theoretical foundations for the theory, how it relates to other phase transition phenomena and its advantages in evolutionary computation and complex adaptive systems. The book provides methods and techniques to use this concept for problem solving. Dual phase evolution concerns systems that evolve via repeated phase shifts in the connectivity of their elements. It occurs in vast range of settings, including natural systems (species evolution, landscape ecology, geomorphology), socio-economic systems (social networks) and in artificial systems (annealing, evolutionary computing).

  13. Power flow analysis for DC voltage droop controlled DC microgrids

    DEFF Research Database (Denmark)

    Li, Chendan; Chaudhary, Sanjay; Dragicevic, Tomislav

    2014-01-01

    This paper proposes a new algorithm for power flow analysis in droop controlled DC microgrids. By considering the droop control in the power flow analysis for the DC microgrid, when compared with traditional methods, more accurate analysis results can be obtained. The algorithm verification...... is carried out by comparing the calculation results with detailed time domain simulation results. With the droop parameters as variables in the power flow analysis, their effects on power sharing and secondary voltage regulation can now be analytically studied, and specialized optimization in the upper level...... control can also be made accordingly. Case studies on power sharing and secondary voltage regulation are carried out using proposed power flow analysis....

  14. Accuracy of impressions obtained with dual-arch trays.

    Science.gov (United States)

    Wöstmann, Bernd; Rehmann, Peter; Balkenhol, Markus

    2009-01-01

    This study aimed to analyze the accuracy resulting from dual-arch impressions when compared to conventional impressions in complex preparations (ie, inlay and partial crown). One hundred eighty impressions were made using two different dual-arch trays; conventional trays served as the control. The accuracy of the dies obtained (Fuji-Rock EP, GC Europe) was assessed indirectly from the change of 59 transversal dimensions. Statistical analysis (t test, analysis of variance) revealed that less rigid dual-arch trays performed better than rigid ones. Though the inlay preparation was more difficult to reproduce with dual-arch trays, it can be concluded that the accuracy obtainable with nonrigid dual-arch trays is comparable to impressions taken from full-arch trays.

  15. Commuting Dual Toeplitz Operators on the Polydisk

    Institute of Scientific and Technical Information of China (English)

    Yu Feng LU; Shu Xia SHANG

    2007-01-01

    On the polydisk, the commutativity of dual Toeplitz operators is studied. We obtain characterizations of commuting dual Toeplitz operators, essentially commuting dual Toeplitz operators and essentially semi-commuting dual Toeplitz operators.

  16. Design of Dual Dynamic Flip-Flop with Featuring Efficient Embedded Logic for Low Power Cmos Vlsi Circuits

    Directory of Open Access Journals (Sweden)

    Adhiyaman P1 ,

    2014-03-01

    Full Text Available In this paper, we introduce a new dual dynamic node hybrid flip-flop (DDFF and a novel embedded logic module (DDFF-ELM based on DDFF. The proposed designs eliminate the large capacitance present in the pre-charge node of several state-of-the-art designs by following a split dynamic node structure to separately drive the output pull-up and pull down transistors. The aim of the DDFF-ELM is to reduce pipeline overhead. It presents an area, power, and speed efficient method to incorporate complex logic functions into the flip-flop. The performance comparisons made in a 90 nm technology when compared to the Semi dynamic flip-flop, with no degradation in speed performance. The leakage power and process-voltage-temperature variations of various designs are studied in detail and are compared with the proposed designs.

  17. Cascaded uncoupled dual-ring modulator

    CERN Document Server

    Gu, Tingyi; Wong, Chee Wei; Dong, Po

    2014-01-01

    We demonstrate that by coherent driving two uncoupled rings in same direction, the effective photon circulating time in the dual ring modulator is reduced, with increased modulation quality. The inter-ring detuning dependent photon dynamics, Q-factor, extinction ratio and optical modulation amplitude of two cascaded silicon ring resonators are studied and compared with that of a single ring modulator. Experimentally measured eye diagrams, together with coupled mode theory simulations, demonstrate the enhancement of dual ring configuration at 20 Gbps with a Q ~ 20,000.

  18. Piezo Voltage Controlled Planar Hall Effect Devices

    OpenAIRE

    Bao Zhang; Kang-Kang Meng; Mei-Yin Yang; Edmonds, K. W.; Hao Zhang; Kai-Ming Cai; Yu Sheng; Nan Zhang; Yang Ji; Jian-Hua Zhao; Hou-Zhi Zheng; Kai-You Wang

    2015-01-01

    The electrical control of the magnetization switching in ferromagnets is highly desired for future spintronic applications. Here we report on hybrid piezoelectric (PZT)/ferromagnetic (Co2FeAl) devices in which the planar Hall voltage in the ferromagnetic layer is tuned solely by piezo voltages. The change of planar Hall voltage is associated with magnetization switching through 90° in the plane under piezo voltages. Room temperature magnetic NOT and NOR gates are demonstrated based on the pie...

  19. 49 CFR 234.221 - Lamp voltage.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Lamp voltage. 234.221 Section 234.221 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION..., Inspection, and Testing Maintenance Standards § 234.221 Lamp voltage. The voltage at each lamp shall...

  20. Bootstrapped Low-Voltage Analog Switches

    DEFF Research Database (Denmark)

    Steensgaard-Madsen, Jesper

    1999-01-01

    Novel low-voltage constant-impedance analog switch circuits are proposed. The switch element is a single MOSFET, and constant-impedance operation is obtained using simple circuits to adjust the gate and bulk voltages relative to the switched signal. Low-voltage (1-volt) operation is made feasible...

  1. Voltage controlled resistor using quasi-floating-gate MOSFETs

    Directory of Open Access Journals (Sweden)

    Susheel Sharma

    2013-01-01

    Full Text Available A voltage controlled resistor (VCR using quasi-floating-gate MOSFETs (QFGMOS suitable for low voltage applications is presented. The performance of the VCR implemented with QFGMOS is compared with its floating-gate MOSFET (FGMOS version. It was found that QFGMOS offers better performance than FGMOS in terms of frequency response, offsets and chip area. The VCR using QFGMOS offers high bandwidth and low power dissipation and yields high value of resistance as compared to its FGMOS counterpart. The workability of the presented circuits was tested by PSpice simulations using level 3 parameters of 0.5μm CMOS technology with supply voltage of ± 0.75V. The simulations results were found to be in accordance with the theoretical predictions.

  2. Early Dual Language Learning

    Science.gov (United States)

    Genesee, Fred

    2008-01-01

    Parents and child care personnel in English-dominant parts of the world often express misgivings about raising children bilingually. Their concerns are based on the belief that dual language learning during the infant-toddler stage confuses children, delays their development, and perhaps even results in reduced language competence. In this…

  3. Modelling of Chirality-Dependent Current-Voltage Characteristics of Carbon-Nanotube Field-Effect Transistors

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xu; WANG Yan; YU Zhi-Ping

    2006-01-01

    @@ Current-voltage characteristics of ballistic carbon-nanotube field-effect transistors are characterized with an it-erative simulation program. The influence of carbon-nanotube chirality and diameter on the output current is considered. An analytical current-voltage expression under the quantum capacitance limit and low-voltage application is derived. Our simulation results are compared with actual measurement data.

  4. Musical expertise has minimal impact on dual task performance.

    Science.gov (United States)

    Cocchini, Gianna; Filardi, Maria Serena; Crhonkova, Marcela; Halpern, Andrea R

    2017-05-01

    Studies investigating effect of practice on dual task performance have yielded conflicting findings, thus supporting different theoretical accounts about the organisation of attentional resources when tasks are performed simultaneously. Because practice has been proven to reduce the demand of attention for the trained task, the impact of long-lasting training on one task is an ideal way to better understand the mechanisms underlying dual task decline in performance. Our study compared performance during dual task execution in expert musicians compared to controls with little if any musical experience. Participants performed a music recognition task and a visuo-spatial task separately (single task) or simultaneously (dual task). Both groups showed a significant but similar performance decline during dual tasks. In addition, the two groups showed a similar decline of dual task performance during encoding and retrieval of the musical information, mainly attributed to a decline in sensitivity. Our results suggest that attention during dual tasks is similarly distributed by expert and non-experts. These findings are in line with previous studies showing a lack of sensitivity to difficulty and lack of practice effect during dual tasks, supporting the idea that different tasks may rely on different and not-sharable attentional resources.

  5. A Dual-Buck–Boost AC/DC Converter for DC Nanogrid With Three Terminal Outputs

    DEFF Research Database (Denmark)

    Wu, Weimin; Wang, Houqing; Liu, Yuan

    2017-01-01

    such as the low-voltage ac power system. There are three typical grounding configurations for a dc nanogrid: the united grounding, the unidirectional grounding, and the virtual isolated grounding. Each grounding configuration has its own specifications to ac/dc converters. In this paper, a dual-buck-boost ac...

  6. DUAL THREE-PHASE ADJUSTABLE SPEED DRIVE WITH SYNCHRONIZED SPACE-VECTOR MODULATION

    Directory of Open Access Journals (Sweden)

    Oleschuk V.I.

    2008-04-01

    Full Text Available Split-phase symmetrical motor drive on the base of two voltage source inverters, controlled by algorithms of synchronized pulse width modulation (PWM, has been investigated. Simulation results are presented for dual three-phase power conversion systems with continuous, discontinuous and combined versions of synchronized PWM.

  7. Voltage Management in Unbalanced Low Voltage Networks Using a Decoupled Phase-Tap-Changer Transformer

    DEFF Research Database (Denmark)

    Coppo, Massimiliano; Turri, Roberto; Marinelli, Mattia

    2014-01-01

    The paper studies a medium voltage-low voltage transformer with a decoupled on load tap changer capability on each phase. The overall objective is the evaluation of the potential benefits on a low voltage network of such possibility. A realistic Danish low voltage network is used for the analysis...

  8. Estimating Voltage Asymmetry Making by One Phase Micro-generator in Low Voltage Network

    Directory of Open Access Journals (Sweden)

    Marian Sobierajski

    2014-12-01

    Full Text Available Connection of one phase micro-generator to the low voltage network increases voltage asymmetry. The voltage asymmetry is defined as the quotient of negative and positive voltage components. The mathematical background of exact and rough computation of the asymmetry quotient is presented in the paper. Considerations are illustrated by simple examples.

  9. 76 FR 70721 - Voltage Coordination on High Voltage Grids; Notice of Staff Workshop

    Science.gov (United States)

    2011-11-15

    ... Energy Regulatory Commission Voltage Coordination on High Voltage Grids; Notice of Staff Workshop Take notice that the Federal Energy Regulatory Commission will hold a Workshop on Voltage Coordination on High Voltage Grids on Thursday, December 1, 2011 from 9 a.m. to 4:30 p.m. This staff-led workshop will be...

  10. X-ray crystal structure of voltage-gated proton channel.

    Science.gov (United States)

    Takeshita, Kohei; Sakata, Souhei; Yamashita, Eiki; Fujiwara, Yuichiro; Kawanabe, Akira; Kurokawa, Tatsuki; Okochi, Yoshifumi; Matsuda, Makoto; Narita, Hirotaka; Okamura, Yasushi; Nakagawa, Atsushi

    2014-04-01

    The voltage-gated proton channel Hv1 (or VSOP) has a voltage-sensor domain (VSD) with dual roles of voltage sensing and proton permeation. Its gating is sensitive to pH and Zn(2+). Here we present a crystal structure of mouse Hv1 in the resting state at 3.45-Å resolution. The structure showed a 'closed umbrella' shape with a long helix consisting of the cytoplasmic coiled coil and the voltage-sensing helix, S4, and featured a wide inner-accessible vestibule. Two out of three arginines in S4 were located below the phenylalanine constituting the gating charge-transfer center. The extracellular region of each protomer coordinated a Zn(2+), thus suggesting that Zn(2+) stabilizes the resting state of Hv1 by competing for acidic residues that otherwise form salt bridges with voltage-sensing positive charges on S4. These findings provide a platform for understanding the general principles of voltage sensing and proton permeation.

  11. Improving transition voltage spectroscopy of molecular junctions

    DEFF Research Database (Denmark)

    Markussen, Troels; Chen, Jingzhe; Thygesen, Kristian Sommer

    2011-01-01

    Transition voltage spectroscopy (TVS) is a promising spectroscopic tool for molecular junctions. The principles in TVS is to find the minimum on a Fowler-Nordheim plot where ln(I/V2) is plotted against 1/V and relate the voltage at the minimum Vmin to the closest molecular level. Importantly, Vmin...... is approximately half the voltage required to see a peak in the dI/dV curve. Information about the molecular level position can thus be obtained at relatively low voltages. In this work we show that the molecular level position can be determined at even lower voltages, Vmin(α), by finding the minimum of ln...

  12. Piezo Voltage Controlled Planar Hall Effect Devices

    Science.gov (United States)

    Zhang, Bao; Meng, Kang-Kang; Yang, Mei-Yin; Edmonds, K. W.; Zhang, Hao; Cai, Kai-Ming; Sheng, Yu; Zhang, Nan; Ji, Yang; Zhao, Jian-Hua; Zheng, Hou-Zhi; Wang, Kai-You

    2016-06-01

    The electrical control of the magnetization switching in ferromagnets is highly desired for future spintronic applications. Here we report on hybrid piezoelectric (PZT)/ferromagnetic (Co2FeAl) devices in which the planar Hall voltage in the ferromagnetic layer is tuned solely by piezo voltages. The change of planar Hall voltage is associated with magnetization switching through 90° in the plane under piezo voltages. Room temperature magnetic NOT and NOR gates are demonstrated based on the piezo voltage controlled Co2FeAl planar Hall effect devices without the external magnetic field. Our demonstration may lead to the realization of both information storage and processing using ferromagnetic materials.

  13. Piezo Voltage Controlled Planar Hall Effect Devices.

    Science.gov (United States)

    Zhang, Bao; Meng, Kang-Kang; Yang, Mei-Yin; Edmonds, K W; Zhang, Hao; Cai, Kai-Ming; Sheng, Yu; Zhang, Nan; Ji, Yang; Zhao, Jian-Hua; Zheng, Hou-Zhi; Wang, Kai-You

    2016-06-22

    The electrical control of the magnetization switching in ferromagnets is highly desired for future spintronic applications. Here we report on hybrid piezoelectric (PZT)/ferromagnetic (Co2FeAl) devices in which the planar Hall voltage in the ferromagnetic layer is tuned solely by piezo voltages. The change of planar Hall voltage is associated with magnetization switching through 90° in the plane under piezo voltages. Room temperature magnetic NOT and NOR gates are demonstrated based on the piezo voltage controlled Co2FeAl planar Hall effect devices without the external magnetic field. Our demonstration may lead to the realization of both information storage and processing using ferromagnetic materials.

  14. A dual neural network for convex quadratic programming subject to linear equality and inequality constraints

    Science.gov (United States)

    Zhang, Yunong; Wang, Jun

    2002-06-01

    A recurrent neural network called the dual neural network is proposed in this Letter for solving the strictly convex quadratic programming problems. Compared to other recurrent neural networks, the proposed dual network with fewer neurons can solve quadratic programming problems subject to equality, inequality, and bound constraints. The dual neural network is shown to be globally exponentially convergent to optimal solutions of quadratic programming problems. In addition, compared to neural networks containing high-order nonlinear terms, the dynamic equation of the proposed dual neural network is piecewise linear, and the network architecture is thus much simpler. The global convergence behavior of the dual neural network is demonstrated by an illustrative numerical example.

  15. Capacitor Voltages Measurement and Balancing in Flying Capacitor Multilevel Converters Utilizing a Single Voltage Sensor

    DEFF Research Database (Denmark)

    Farivar, Glen; Ghias, Amer M. Y. M.; Hredzak, Branislav

    2017-01-01

    This paper proposes a new method for measuring capacitor voltages in multilevel flying capacitor (FC) converters that requires only one voltage sensor per phase leg. Multiple dc voltage sensors traditionally used to measure the capacitor voltages are replaced with a single voltage sensor at the ac...... side of the phase leg. The proposed method is subsequently used to balance the capacitor voltages using only the measured ac voltage. The operation of the proposed measurement and balancing method is independent of the number of the converter levels. Experimental results presented for a five-level FC...

  16. HIGH VOLTAGE SMALL – SIZED ALTERNATIVE CURRENT RESISTIVE DIVIDERS FROM MICROWIRE

    Directory of Open Access Journals (Sweden)

    Berzan V.P.

    2011-04-01

    Full Text Available The paper discusses the design parameters and characteristics of the new product, the resistive voltage divider produced from microwire for measuring high-voltage alternating current. Resistive dividers are designed for use in AC circuits and power-frequency electric traction network traffic. Dividers have smaller mass-dimensional size compared with the measuring voltage transformers and higher accuracy class 0.2 at a fixed frequency.

  17. Voltage-Sensitive Load Controllers for Voltage Regulation and Increased Load Factor in Distribution Systems

    DEFF Research Database (Denmark)

    Douglass, Philip James; Garcia-Valle, Rodrigo; Østergaard, Jacob

    2014-01-01

    consumption which can be mapped to temperature setpoint offsets of thermostat controlled loads. In networks where a lower voltage level corresponds to high system load (and vice versa), this controller acts to regulate voltage and increase the load factor. Simulations are conducted on low- and medium-voltage......This paper presents a novel controller design for controlling appliances based on local measurements of voltage. The controller finds the normalized voltage deviation accounting for the sensitivity of voltage measurements to appliance state. The controller produces a signal indicating desired power...... distribution systems with residential loads including voltage-sensitive water heaters. In low-voltage systems, the results of the simulations show the controller to be effective at reducing the extremes of voltage and increasing the load factor while respecting end-use temperature constraints. In medium-voltage...

  18. Voltage-controlled photonic oscillator.

    Science.gov (United States)

    Savchenkov, A A; Ilchenko, V S; Liang, W; Eliyahu, D; Matsko, A B; Seidel, D; Maleki, L

    2010-05-15

    We report the development and demonstration of an X-band voltage-controlled photonic oscillator based on a whispering gallery mode resonator made of an electro-optic crystalline material. The oscillator has good spectral purity and wide, agile, linear tunability. We have modified the existing theoretical model of the opto-electronic oscillator to describe the performance of our tunable oscillator and have found a good agreement between the theoretical predictions and the measurement results. We show that the device is promising for higher-frequency applications where high-performance tunable oscillators with wide tunability do not exist.

  19. Enhancement of Voltage Stability of DC Smart Grid During Islanded Mode by Load Shedding Scheme

    Science.gov (United States)

    Nassor, Thabit Salim; Senjyu, Tomonobu; Yona, Atsushi

    2015-10-01

    This paper presents the voltage stability of a DC smart grid based on renewable energy resources during grid connected and isolated modes. During the islanded mode the load shedding, based on the state of charge of the battery and distribution line voltage, was proposed for voltage stability and reservation of critical load power. The analyzed power system comprises a wind turbine, a photovoltaic generator, storage battery as controllable load, DC loads, and power converters. A fuzzy logic control strategy was applied for power consumption control of controllable loads and the grid-connected dual active bridge series resonant converters. The proposed DC Smart Grid operation has been verified by simulation using MATLAB® and PLECS® Blockset. The obtained results show the effectiveness of the proposed method.

  20. Voltage Management in Unbalanced Low Voltage Networks Using a Decoupled Phase-Tap-Changer Transformer

    OpenAIRE

    Coppo, Massimiliano; Turri, Roberto; Marinelli, Mattia; Han, Xue

    2014-01-01

    The paper studies a medium voltage-low voltage transformer with a decoupled on load tap changer capability on each phase. The overall objective is the evaluation of the potential benefits on a low voltage network of such possibility. A realistic Danish low voltage network is used for the analysis. The load profiles are characterized by using single phase measurement data on voltages, currents and active powers with a 10 minutes resolution. Different scenarios are considered: no tap action, th...

  1. Dual diagnosis among physicians: a clinical perspective.

    Science.gov (United States)

    Braquehais, María Dolores; Lusilla, Pilar; Bel, Miquel Jordi; Navarro, María Cecilia; Nasillo, Viviana; Díaz, Albert; Valero, Sergi; Padrós, Jaume; Bruguera, Eugeni; Casas, Miquel

    2014-01-01

    Co-occurrence of mental disorders and substance use disorders (dual diagnosis) among doctors is a cause of serious concern due to its negative personal, professional, and social consequences. This work provides an overview of the prevalence of dual diagnosis among physicians, suggests a clinical etiological model to explain the development of dual diagnosis in doctors, and recommends some treatment strategies specifically for doctors. The most common presentation of dual diagnosis among doctors is the combination of alcohol use disorders and affective disorders. There are also high rates of self-medication with benzodiazepines, legal opiates, and amphetamines compared to the general population, and cannabis use disorders are increasing, mainly in young doctors. The prevalence of nicotine dependence varies from one country to another depending on the nature of public health policies. Emergency medicine physicians, psychiatrists, and anaesthesiologists are at higher risk for developing a substance use disorder compared with other doctors, perhaps because of their knowledge of and access to certain legal drugs. Two main pathways may lead doctors toward dual diagnosis: (a) the use of substances (often alcohol or self-prescribed drugs) as an unhealthy strategy to cope with their emotional or mental distress and (b) the use of substances for recreational or other purposes. In both cases, doctors tend to delay seeking help once a problem has been established, often for many years. Denial, minimization, and rationalization are common defense mechanisms, maybe because of the social stigma associated with mental or substance use disorders, the risk of losing employment/medical license, and a professional culture of perfectionism and denial of emotional needs or failures. Personal vulnerability interacts with these factors to increase the risk of a dual diagnosis developing in some individuals. When doctors with substance use disorders accept treatment in programs

  2. Enhanced antitumor effect of novel dual-targeted paclitaxel liposomes

    Energy Technology Data Exchange (ETDEWEB)

    Meng Shuyan; Su Bo; Li Wei; Ding Yongmei; Tang Liang; Zhou Wei; Song Yin; Li Heyan; Zhou Caicun, E-mail: caicunzhou@yahoo.com.cn [Cancer Institute of Tongji University School of Medicine, Shanghai Pulmonary Hospital, 507 Zhengmin Road, Shanghai (China)

    2010-10-15

    A novel dual-targeted peptide containing an alpha V integrins specific ligand and a neuropilin-1 specific motif was developed which showed an increased specific targeting affinity to tumors. Active dual-targeted liposomes were then produced with this peptide and exhibited greater binding activity than single-targeted liposomes in vitro. Paclitaxel entrapped in this formulation greatly increased the uptake of paclitaxel in the targeting cells and significantly suppressed the growth of HUVEC and A549 cells compared with general paclitaxel injections (Taxol) and single-targeted paclitaxel liposomes. The treatment of tumor xenograft models with dual-targeted paclitaxel liposomes also resulted in better tumor growth inhibition than any other treatment groups. Therefore, the dual-targeted paclitaxel liposomes prepared in the present study might be a more promising drug for cancer treatment. Furthermore, the dual-targeting approach may produce synergistic effects that can be applied in the development of new targeted drug delivery systems.

  3. SISTEM KONTROL OTOMATIK DENGAN MODEL SINGLE-INPUT-DUAL-OUTPUT DALAM KENDALI EFISIENSI UMUR-PEMAKAIAN INSTRUMEN

    Directory of Open Access Journals (Sweden)

    S.N.M.P. Simamora

    2014-10-01

    Full Text Available Efficiency condition occurs when the value of the used outputs compared to the resource total that has been used almost close to the value 1 (absolute environment. An instrument to achieve efficiency if the power output level has decreased significantly in the life of the instrument used, if it compared to the previous condition, when the instrument is not equipped with additional systems (or proposed model improvement. Even more effective if the inputs model that are used in unison to achieve a homogeneous output. On this research has been designed and implemented the automatic control system for models of single input-dual-output, wherein the sampling instruments used are lamp and fan. Source voltage used is AC (alternate-current and tested using quantitative research methods and instrumentation (with measuring instruments are observed. The results obtained demonstrate the efficiency of the instrument experienced a significant current model of single-input-dual-output applied separately instrument trials such as lamp and fan when it compared to the condition or state before. And the result show that the design has been built, can also run well.

  4. Ultrabroadband Electro-Optic Modulator Based on Hybrid Silicon-Polymer Dual Vertical Slot Waveguide

    Directory of Open Access Journals (Sweden)

    Shouyuan Shi

    2011-01-01

    Full Text Available We present a novel hybrid silicon-polymer dual slot waveguide for high speed and ultra-low driving voltage electro-optic (EO modulation. The proposed design utilizes the unique properties of ferroelectric materials such as LiNbO3 to achieve dual RF and optical modes within a low index nanoslot. The tight mode concentration and overlap in the slot allow the infiltrated organic EO polymers to experience enhanced nonlinear interaction with the applied electric field. Half-wavelength voltage-length product and electro-optic response are rigorously simulated to characterize the proposed design, which reveals ultrabroadband operation, up to 250 GHz, and subvolt driving voltage for a 1 cm long modulator.

  5. Advanced medium-voltage bidirectional dc-dc conversion systems for future electric energy delivery and management systems

    Science.gov (United States)

    Fan, Haifeng

    2011-12-01

    switching loss and conduction loss are must-haves for high efficiency, while bidirectional power flow capability is a must for power management requirement. To address the demand, the phase-shift dual-halfbridge (DHB) is proposed as the constituent module of ISOP configuration for MV application. The proposed ISOP DHB converter employs zero-voltage-switching (ZVS) technique combined with LV MOSFETs to achieve low switching and conduction losses under high frequency operation, and therefore high efficiency and high power density, and bidirectional power flow as well. Secondly, a large load range of high efficiency is desired rather than only a specific load point due to the continuous operation and large load variation range of utility application, which is of high importance because of the rising energy cost. This work proposes a novel DHB converter with an adaptive commutation inductor. By utilizing an adaptive inductor as the main energy transfer element, the output power can be controlled by not only the phase shift but also the commutation inductance, which allows the circulating energy to be optimized for different load conditions to maintain ZVS under light load conditions and minimize additional conduction losses under heavy load conditions as well. As a result, the efficiency at both light and heavy load can be significantly improved compared with the conventional DHB converter, and therefore extended high-efficiency range can be achieved. In addition, current stress of switch devices can be reduced. The theoretical analysis is presented and validated by the experimental results on a 50 kHz, 1 kW dc-dc converter module. Thirdly, input-voltage sharing and output-current sharing are critical to assure the advantages of the ISOP modular configuration. To solve this issue, an identically distributed control scheme is proposed in this work. The proposed control scheme, using only one distributed voltage loop to realize both input-voltage and output-current sharing

  6. High voltage pulsed cable design: a practical example

    Energy Technology Data Exchange (ETDEWEB)

    Kewish, R.W. Jr.; Boicourt, G.P.

    1979-01-01

    The design of optimum high voltage pulse cable is difficult because very little emperical data are available on performance in pulsed applications. This paper follows the design and testing of one high voltage pulse cable, 40/100 trigger cable. The design was based on an unproven theory and the impressive outcome lends support to the theory. The theory is outlined and it is shown that there exists an inductance which gives a cable of minimum size for a given maximum stress. Test results on cable manufactured according to the design are presented and compared with the test results on the cable that 40/100 replaces.

  7. Nonlinear series resonance and standing waves in dual-frequency capacitive discharges

    Science.gov (United States)

    Wen, De-Qi; Kawamura, E.; Lieberman, M. A.; Lichtenberg, A. J.; Wang, You-Nian

    2017-01-01

    It is well-known that the nonlinear series resonance in a high frequency capacitive discharge enhances the electron power deposition and also creates standing waves which produce radially center-high rf voltage profiles. In this work, the dynamics of series resonance and wave effects are examined in a dual-frequency driven discharge, using an asymmetric radial transmission line model incorporating a Child law sheath. We consider a cylindrical argon discharge with a conducting electrode radius of 15 cm, gap length of 3 cm, with a base case having a 60 MHz high frequency voltage of 250 V and a 10 MHz low frequency voltage of 1000 V, with a high frequency phase shift {φ\\text{H}}=π between the two frequencies. For this phase shift there is only one sheath collapse, and the time-averaged spectral peaks of the normalized current density at the center are mainly centered on harmonic numbers 30 and 50 of the low frequency, corresponding to the first standing wave resonance frequency and the series resonance frequency, respectively. The effects of the waves on the series resonance dynamics near the discharge center give rise to significant enhancements in the electron power deposition, compared to that near the discharge edge. Adjusting the phase shift from π to 0, or decreasing the low frequency from 10 to 2 MHz, results in two or more sheath collapses, respectively, making the dynamics more complex. The sudden excitation of the perturbed series resonance current after the sheath collapse results in a current oscillation amplitude that is estimated from analytical and numerical calculations. Self-consistently determining the dc bias and including the conduction current is found to be important. The subsequent slow time variation of the high frequency oscillation is analyzed using an adiabatic theory.

  8. Higher Representations Duals

    DEFF Research Database (Denmark)

    Sannino, Francesco

    2010-01-01

    We uncover novel solutions of the 't Hooft anomaly matching conditions for scalarless gauge theories with matter transforming according to higher dimensional representations of the underlying gauge group. We argue that, if the duals exist, they are gauge theories with fermions transforming...... according to the defining representation of the dual gauge group. The resulting conformal windows match the one stemming from the all-orders beta function results when taking the anomalous dimension of the fermion mass to be unity which are also very close to the ones obtained using the Schwinger......-Dyson approximation. We use the solutions to gain useful insight on the conformal window of the associated electric theory. A consistent picture emerges corroborating previous results obtained via different analytic methods and in agreement with first principle lattice explorations....

  9. Dual Campus High School

    Directory of Open Access Journals (Sweden)

    Carmen P. Mombourquette

    2013-04-01

    Full Text Available September 2010 witnessed the opening of the first complete dual campus high school in Alberta. Catholic Central High School, which had been in existence since 1967 in one building, now offered courses to students on two campuses. The “dual campus” philosophy was adopted so as to ensure maximum program flexibility for students. The philosophy, however, was destined to affect student engagement and staff efficacy as the change in organizational structure, campus locations, and course availability was dramatic. Changing school organizational structure also had the potential of affecting student achievement. A mixed-methods study utilizing engagement surveys, efficacy scales, and interviews with students and teachers was used to ascertain the degree of impact. The results of the study showed that minimal impact occurred to levels of student engagement, minor negative impact to staff efficacy, and a slight increase to student achievement results.

  10. Dual-comb MIXSEL

    Science.gov (United States)

    Link, S. M.; Zaugg, C. A.; Klenner, A.; Mangold, M.; Golling, M.; Tilma, B. W.; Keller, U.

    2015-03-01

    We present a single semiconductor disk laser simultaneously emitting two different gigahertz modelocked pulse trains. A birefringent crystal inside a modelocked integrated external-cavity surface-emitting laser (MIXSEL) separates the cavity beam into two spatially separated beams with perpendicular polarizations on the MIXSEL chip. This MIXSEL then generates two orthogonally polarized collinear modelocked pulse trains from one simple straight cavity. Superimposing the beams on a photo detector creates a microwave beat signal, representing a strikingly simple setup to down-convert the terahertz optical frequencies into the electronically accessible microwave regime. This makes the dual-comb MIXSEL scheme an ultra-compact and cost-efficient candidate for dual-comb spectroscopy applications.

  11. 49 CFR 236.551 - Power supply voltage; requirement.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Power supply voltage; requirement. 236.551 Section... supply voltage; requirement. The voltage of power supply shall be maintained within 10 percent of rated voltage....

  12. Strongly nonlinear dynamics of electrolytes in large ac voltages

    DEFF Research Database (Denmark)

    Olesen, Laurits Højgaard; Bazant, Martin Z.; Bruus, Henrik

    2010-01-01

    We study the response of a model microelectrochemical cell to a large ac voltage of frequency comparable to the inverse cell relaxation time. To bring out the basic physics, we consider the simplest possible model of a symmetric binary electrolyte confined between parallel-plate blocking electrodes...... in the electrolyte near the electrodes and, at very large voltage, the breakdown of the quasiequilibrium structure of the double layers. The former leads to the prediction of “ac capacitive desalination” since there is a time-averaged transfer of salt from the bulk to the double layers, via oscillating diffusion...... nonlinear responses to large ac voltages, such as Faradaic reactions, electro-osmotic instabilities, and induced-charge electrokinetic phenomena....

  13. Dual-readout Calorimetry

    OpenAIRE

    Akchurin, N.; Bedeschi, F.; Cardini, A.; Cascella, M.; Cei, F.; Pedis, D.; Fracchia, S.; Franchino, S.; Fraternali, M.; Gaudio, G.; P. Genova; Hauptman, J.; La Rotonda, L.; Lee, S.; Livan, M.(INFN Sezione di Pavia, Pavia, Italy)

    2013-01-01

    The RD52 Project at CERN is a pure instrumentation experiment whose goal is to understand the fundamental limitations to hadronic energy resolution, and other aspects of energy measurement, in high energy calorimeters. We have found that dual-readout calorimetry provides heretofore unprecedented information event-by-event for energy resolution, linearity of response, ease and robustness of calibration, fidelity of data, and particle identification, including energy lost to binding energy in n...

  14. Lithium-copper molybdate voltage compatible battery

    Energy Technology Data Exchange (ETDEWEB)

    Bonino, F.; Lazzari, M.

    1984-03-01

    Li/organic-electrolyte/CuMoO4 battery systems are evaluated experimentally at 1.5-V operating voltage and energy densities (0.5 and 0.3 mA/sq cm) typical of batteries used in microelectronic devices. Electrolytes tested include LiClO4 and LiCF3SO3 in propylene carbonate and LiAsF6 in butyrolactone. The results are presented in graphs and discussed. The superiority of LiClO4 as an electrolyte salt and the feasibility of CuMoO4 as cathode are demonstrated. The energy density of the CuMoO4-cathode cell when discharged at 0.3 mA/sq cm to cutoff at 1 V is found to be 440 Wh/kg, comparable to that found in a Cu2S-cathode Li cell. 5 references.

  15. Ultra-low-voltage-trigger thyristor for on-chip ESD protection without extra process cost

    Science.gov (United States)

    Yi, Shan; Jun, He; Wenyi, Huang

    2009-07-01

    A new thyristor is proposed and realized in the foundry's 0.18-μm CMOS process for electrostatic discharge (ESD) protection. Without extra mask layers or process steps, the new ultra-low-voltage-trigger thyristor (ULVT thyristor) has a trigger voltage as low as 6.7 V and an ESD robustness exceeding 50 mA/μm, which enables effective ESD protection. Compared with the traditional medium-voltage-trigger thyristor (MVT thyristor), the new structure not only has a lower trigger voltage, but can also provide better ESD protection under both positive and negative ESD zapping conditions.

  16. Ultra-low-voltage-trigger thyristor for on-chip ESD protection without extra process cost

    Energy Technology Data Exchange (ETDEWEB)

    Shan Yi [Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); He Jun; Huang Wenyi, E-mail: iamshanyi@163.co, E-mail: yi.shan@gracesemi.co [Grace Semiconductor Manufacturing Corporation, Shanghai 201203 (China)

    2009-07-15

    A new thyristor is proposed and realized in the foundry's 0.18-{mu}m CMOS process for electrostatic discharge (ESD) protection. Without extra mask layers or process steps, the new ultra-low-voltage-trigger thyristor (ULVT thyristor) has a trigger voltage as low as 6.7 V and an ESD robustness exceeding 50 mA/{mu}m, which enables effective ESD protection. Compared with the traditional medium-voltage-trigger thyristor (MVT thyristor), the new structure not only has a lower trigger voltage, but can also provide better ESD protection under both positive and negative ESD zapping conditions.

  17. The Semiconductor Self-Excitation System of Synchronous Generator with Fuzzy Voltage Regulator

    Directory of Open Access Journals (Sweden)

    Kutsyk, А.S.

    2014-05-01

    Full Text Available The synchronous generator’s voltage control system with the synthesized fuzzy voltage regulator is described. The synthesis of the regulator is carried out with the use of mathematical model taking into account the nonlinearity of synchronous machines and semiconductor converters in the e xcitation system. This distinguishes it from traditional excitation regulators, whose synthesis is based on the use of simplified linearized models. The mathematical modeling results allow to compare the control characteristics in the system with the proposed fuzzy voltage regulator and in the system with a traditional voltage controller.

  18. Design and Simulation of a Low Actuation Voltage Capacitive Micro Electro Mechanical Systems’ (MEMS Switch

    Directory of Open Access Journals (Sweden)

    Ayub Soltani

    2014-09-01

    Full Text Available In this paper we have proposed a new switch or structure for reducing actuation voltage. This switch is compared with four conventional structures considering the force range of 1uN to 3uN. We have used the ANSYS software for design and simulation for the switch parameters such as actuation voltage, collapse voltage, spring constant and resonant frequency. Small size (half of the size of other proposed materials, which can reduce the manufacturing cost, and also low-valued spring constant, which results in actuation voltage reduction, are among more noticeable features of the proposed switch.

  19. Dual-Schemata Model

    Science.gov (United States)

    Taniguchi, Tadahiro; Sawaragi, Tetsuo

    In this paper, a new machine-learning method, called Dual-Schemata model, is presented. Dual-Schemata model is a kind of self-organizational machine learning methods for an autonomous robot interacting with an unknown dynamical environment. This is based on Piaget's Schema model, that is a classical psychological model to explain memory and cognitive development of human beings. Our Dual-Schemata model is developed as a computational model of Piaget's Schema model, especially focusing on sensori-motor developing period. This developmental process is characterized by a couple of two mutually-interacting dynamics; one is a dynamics formed by assimilation and accommodation, and the other dynamics is formed by equilibration and differentiation. By these dynamics schema system enables an agent to act well in a real world. This schema's differentiation process corresponds to a symbol formation process occurring within an autonomous agent when it interacts with an unknown, dynamically changing environment. Experiment results obtained from an autonomous facial robot in which our model is embedded are presented; an autonomous facial robot becomes able to chase a ball moving in various ways without any rewards nor teaching signals from outside. Moreover, emergence of concepts on the target movements within a robot is shown and discussed in terms of fuzzy logics on set-subset inclusive relationships.

  20. A NOVEL METHOD OF VOLTAGE SAG AND SWELL ESTIMATION FOR POWER SYSTEM APPLICATIONS

    Directory of Open Access Journals (Sweden)

    A. Vetrivel

    2013-01-01

    Full Text Available This study presents four simple mathematical models to build the voltage shape with the knowledge of few parameters and detects voltage sag and swells accurately. Fourier series, cubic polynomial, Rational functions and Sum of Sin functions are used in this study to model the voltage profile. A new algorithm is developed to detect sag or swell in all the four models. The voltage estimation due to cubic polynomial has more voltage error and then rational function. The sum of sine function and Fourier series functions does accurate voltage estimation. Errors due to various functions are also tabulated for one electrical cycle. The performance of each method has been compared with other to know the effectiveness of different models and their results are presented.

  1. A Case Study Of Turkish Transmission System For VoltageDips

    DEFF Research Database (Denmark)

    Inan, E.; Alboyaci, B.; Bak, Claus Leth

    2009-01-01

    Power quality problems usually appear in the form of voltage sags, transients and harmonics. From these three broad categories of power quality problems, voltage dips account the most disturbances experienced by industrial customers. Voltage dips generally refer to instantaneous short...... analysis of voltage dip performance of the whole transmission system, is used to compare with results constructed fault statics from SIMPOW DIPS analysis program real data. SIMPOW DIPS software enables to calculate dip frequency for all busses and lines.......-duration voltage variations. The aim of this paper is to have an idea about voltage dip performance of Turkey Transmission System. Turkey's transmission system has 21 regions. For simulations, 2nd region, which includes Istanbul city's area is heavy loaded, is selected. For purposes of early warning and later...

  2. Distributed Control to Ensure Proportional Load Sharing and Improve Voltage Regulation in Low-Voltage DC Microgrids

    DEFF Research Database (Denmark)

    Anand, Sandeep; G. Fernandes, Baylon; Guerrero, Josep M.

    2013-01-01

    DC microgrids are gaining popularity due to high efficiency, high reliability, and easy interconnection of renewable sources as compared to the ac system. Control objectives of dc microgrid are: 1) to ensure equal load sharing (in per unit) among sources; and 2) to maintain low-voltage regulation...

  3. Optimization of dual-energy CT acquisitions for proton therapy using projection-based decomposition.

    Science.gov (United States)

    Vilches-Freixas, Gloria; Létang, Jean Michel; Ducros, Nicolas; Rit, Simon

    2017-09-01

    Dual-energy computed tomography (DECT) has been presented as a valid alternative to single-energy CT to reduce the uncertainty of the conversion of patient CT numbers to proton stopping power ratio (SPR) of tissues relative to water. The aim of this work was to optimize DECT acquisition protocols from simulations of X-ray images for the treatment planning of proton therapy using a projection-based dual-energy decomposition algorithm. We have investigated the effect of various voltages and tin filtration combinations on the SPR map accuracy and precision, and the influence of the dose allocation between the low-energy (LE) and the high-energy (HE) acquisitions. For all spectra combinations, virtual CT projections of the Gammex phantom were simulated with a realistic energy-integrating detector response model. Two situations were simulated: an ideal case without noise (infinite dose) and a realistic situation with Poisson noise corresponding to a 20 mGy total central dose. To determine the optimal dose balance, the proportion of LE-dose with respect to the total dose was varied from 10% to 90% while keeping the central dose constant, for four dual-energy spectra. SPR images were derived using a two-step projection-based decomposition approach. The ranges of 70 MeV, 90 MeV, and 100 MeV proton beams onto the adult female (AF) reference computational phantom of the ICRP were analytically determined from the reconstructed SPR maps. The energy separation between the incident spectra had a strong impact on the SPR precision. Maximizing the incident energy gap reduced image noise. However, the energy gap was not a good metric to evaluate the accuracy of the SPR. In terms of SPR accuracy, a large variability of the optimal spectra was observed when studying each phantom material separately. The SPR accuracy was almost flat in the 30-70% LE-dose range, while the precision showed a minimum slightly shifted in favor of lower LE-dose. Photon noise in the SPR images (20 mGy dose

  4. Voltage Unbalance Compensation with Smart Three-phase Loads

    DEFF Research Database (Denmark)

    Douglass, Philip; Trintis, Ionut; Munk-Nielsen, Stig

    2016-01-01

    voltage, but it does not reduce the negative sequence voltage. The controller that uses phase-phase voltage as input eliminates negative sequence voltage, and reduces voltage deviations from the average to approximately half their initial value. Current unbalance is reduced when the voltage unbalance...... is caused by asymmetrical loads. These results suggest that the optimal algorithm to reduce system unbalance depends on which system parameter is most important: phase-neutral voltage unbalance, phase-phase voltage unbalance, or current unbalance....

  5. Power conditioning using dynamic voltage restorers under different voltage sag types

    Directory of Open Access Journals (Sweden)

    Ahmed M. Saeed

    2016-01-01

    Full Text Available Voltage sags can be symmetrical or unsymmetrical depending on the causes of the sag. At the present time, one of the most common procedures for mitigating voltage sags is by the use of dynamic voltage restorers (DVRs. By definition, a DVR is a controlled voltage source inserted between the network and a sensitive load through a booster transformer injecting voltage into the network in order to correct any disturbance affecting a sensitive load voltage. In this paper, modelling of DVR for voltage correction using MatLab software is presented. The performance of the device under different voltage sag types is described, where the voltage sag types are introduced using the different types of short-circuit faults included in the environment of the MatLab/Simulink package. The robustness of the proposed device is evaluated using the common voltage sag indices, while taking into account voltage and current unbalance percentages, where maintaining the total harmonic distortion percentage of the load voltage within a specified range is desired. Finally, several simulation results are shown in order to highlight that the DVR is capable of effective correction of the voltage sag while minimizing the grid voltage unbalance and distortion, regardless of the fault type.

  6. Power conditioning using dynamic voltage restorers under different voltage sag types.

    Science.gov (United States)

    Saeed, Ahmed M; Abdel Aleem, Shady H E; Ibrahim, Ahmed M; Balci, Murat E; El-Zahab, Essam E A

    2016-01-01

    Voltage sags can be symmetrical or unsymmetrical depending on the causes of the sag. At the present time, one of the most common procedures for mitigating voltage sags is by the use of dynamic voltage restorers (DVRs). By definition, a DVR is a controlled voltage source inserted between the network and a sensitive load through a booster transformer injecting voltage into the network in order to correct any disturbance affecting a sensitive load voltage. In this paper, modelling of DVR for voltage correction using MatLab software is presented. The performance of the device under different voltage sag types is described, where the voltage sag types are introduced using the different types of short-circuit faults included in the environment of the MatLab/Simulink package. The robustness of the proposed device is evaluated using the common voltage sag indices, while taking into account voltage and current unbalance percentages, where maintaining the total harmonic distortion percentage of the load voltage within a specified range is desired. Finally, several simulation results are shown in order to highlight that the DVR is capable of effective correction of the voltage sag while minimizing the grid voltage unbalance and distortion, regardless of the fault type.

  7. A new modeling of loading margin and its sensitivities using rectangular voltage coordinates in voltage stability analysis

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Vander Menengoy da; Rosa, Arlei Lucas de Sousa [Department of Electrical Engineering, Federal University of Juiz de Fora, Campus Universitario - Bairro Martelos, 36036-330 Juiz de Fora - MG (Brazil); Guedes, Magda Rocha [Federal Center of Technologic Education of Minas Gerais - CEFET, Rua Jose Peres, 558 36700-000 Leopoldina - MG (Brazil); Cantarino, Marcelo [Centrais Eletricas Brasileiras S.A - ELETROBRAS, Av. Rio Branco, 53, Centro, 14 andar, 20090-004 Rio de Janeiro - RJ (Brazil)

    2010-05-15

    This paper presents new mathematical models to compute the loading margin, as well as to perform the sensitivity analysis of loading margin with respect to different electric system parameters. The innovative idea consists of evaluating the performance of these methods when the power flow equations are expressed with the voltages in rectangular coordinates. The objective is to establish a comparative process with the conventional models expressed in terms of power flow equations with the voltages in polar coordinates. IEEE test system and a South-Southeastern Brazilian network are used in the simulations. (author)

  8. A high-voltage rechargeable magnesium-sodium hybrid battery

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yifei; An, Qinyou; Cheng, Yingwen; Liang, Yanliang; Ren, Yang; Sun, Cheng-Jun; Dong, Hui; Tang, Zhongjia; Li, Guosheng; Yao, Yan

    2017-04-01

    Growing global demand of safe and low-cost energy storage technology triggers strong interests in novel battery concepts beyond state-of-art Li-ion batteries. Here we report a high-voltage rechargeable Mg–Na hybrid battery featuring dendrite-free deposition of Mg anode and Na-intercalation cathode as a low-cost and safe alternative to Li-ion batteries for large-scale energy storage. A prototype device using a Na3V2(PO4)3 cathode, a Mg anode, and a Mg–Na dual salt electrolyte exhibits the highest voltage (2.60 V vs. Mg) and best rate performance (86% capacity retention at 10C rate) among reported hybrid batteries. Synchrotron radiation-based X-ray absorption near edge structure (XANES), atomic-pair distribution function (PDF), and high-resolution X-ray diffraction (HRXRD) studies reveal the chemical environment and structural change of Na3V2(PO4)3 cathode during the Na ion insertion/deinsertion process. XANES study shows a clear reversible shift of vanadium K-edge and HRXRD and PDF studies reveal a reversible two-phase transformation and V–O bond length change during cycling. The energy density of the hybrid cell could be further improved by developing electrolytes with a higher salt concentration and wider electrochemical window. This work represents a significant step forward for practical safe and low-cost hybrid batteries.

  9. Voltage-Mode All-Pass Filters Using Universal Voltage Conveyor and MOSFET-Based Electronic Resistors

    Directory of Open Access Journals (Sweden)

    N. Herencsar

    2011-04-01

    Full Text Available The paper presents two novel realizations of voltage-mode first-order all-pass filters. Both circuits use single universal voltage conveyor (UVC, single capacitor, and two grounded resistors. Using the two NMOS transistors-based realizations of the electronic resistor with two symmetrical power supplies, presented all-pass filter circuits can be easily made electronically tunable. Proposed filter structures provide both inverting and non-inverting outputs at the same configuration simultaneously and they have high-input and low-output impedances that are desired for easy cascading in voltage-mode operations. The nonidealities of the proposed circuits are also analyzed and compared. The theoretical results of both circuits are verified by SPICE simulations using TSMC 0.35 μm CMOS process parameters. Based on the evaluation, the behavior of one of the circuits featuring better performance was also experimentally measured using the UVC-N1C 0520 integrated circuit.

  10. High voltage load resistor array

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, Monty Ray [Smithfield, VA

    2005-01-18

    A high voltage resistor comprising an array of a plurality of parallel electrically connected resistor elements each containing a resistive solution, attached at each end thereof to an end plate, and about the circumference of each of the end plates, a corona reduction ring. Each of the resistor elements comprises an insulating tube having an electrode inserted into each end thereof and held in position by one or more hose clamps about the outer periphery of the insulating tube. According to a preferred embodiment, the electrode is fabricated from stainless steel and has a mushroom shape at one end, that inserted into the tube, and a flat end for engagement with the end plates that provides connection of the resistor array and with a load.

  11. A 150-nA 13.4-ppm/℃ switched-capacitor CMOS sub-bandgap voltage reference*

    Institute of Scientific and Technical Information of China (English)

    Yan Wei; Li Wenhong; Liu Ran

    2011-01-01

    A nanopower switched-capacitor CMOS sub-bandgap voltage reference has been implemented using a Chartered 0.35-μm 3.3-V/5-V dual gate mixed-signal CMOS process The proposed circuit generates a precise sub-bandgap voltage of l V. The temperature coefficient of the output voltage is 13.4 ppm/℃ with the temperature varying from-20 to 80 ℃ The proposed circuit operates properly with the supply voltage down to 1.3 V, and consumes 150 nA at room temperature. The line regulation is 0.27%/V The power supply rejection ratio at 100 Hz and l MHz is -39 dB and 51 dB, respectively. The chip area is 0.2 mm2.

  12. Voltage-Controlled Floating Resistor Using DDCC

    Directory of Open Access Journals (Sweden)

    M. Kumngern

    2011-04-01

    Full Text Available This paper presents a new simple configuration to realize the voltage-controlled floating resistor, which is suitable for integrated circuit implementation. The proposed resistor is composed of three main components: MOS transistor operating in the non-saturation region, DDCC, and MOS voltage divider. The MOS transistor operating in the non-saturation region is used to configure a floating linear resistor. The DDCC and the MOS transistor voltage divider are used for canceling the nonlinear component term of MOS transistor in the non-saturation region to obtain a linear current/voltage relationship. The DDCC is employed to provide a simple summer of the circuit. This circuit offers an ease for realizing the voltage divider circuit and the temperature effect that includes in term of threshold voltage can be compensated. The proposed configuration employs only 16 MOS transistors. The performances of the proposed circuit are simulated with PSPICE to confirm the presented theory.

  13. Micromachined dual input axis rate gyroscope

    Science.gov (United States)

    Juneau, Thor Nelson

    The need for inexpensive yet reliable angular rate sensors in fields ranging from automotive to consumer electronics has motivated prolific micromachined rate gyroscope research. The vast majority of research has focused on single input axis rate gyroscopes based upon either translational resonance, such as tuning forks, or structural mode resonance, such as vibrating rings. However, this work presents a novel, contrasting approach based on angular resonance of a rotating rigid rotor suspended by torsional springs. The inherent symmetry of the circular design allows angular rate measurement about two axes simultaneously, hence the name micromachined dual-axis rate gyroscope. The underlying theory of operation, mechanical structure design optimization, electrical interface circuitry, and signal processing are described in detail. Several operational versions were fabricated using two different fully integrated surface micromachining processes as proof of concept. The heart of the dual-axis rate gyroscope is a ˜2 mum thick polysilicon disk or rotor suspended above the substrate by a four beam suspension. When this rotor in driven into angular oscillation about the axis perpendicular to the substrate, a rotation rate about the two axes parallel to the substrate invokes an out of plane rotor tilting motion due to Coriolis acceleration. This tilting motion is capacitively measured and on board integrated signal processing provides two output voltages proportional to angular rate input about the two axes parallel to the substrate. The design process begins with the derivation of gyroscopic dynamics. The equations suggest that tuning sense mode frequencies to the drive oscillation frequency can vastly increase mechanical sensitivity. Hence the supporting four beam suspension is designed such that electrostatic tuning can match modes despite process variations. The electrostatic tuning range is limited only by rotor collapse to the substrate when tuning-voltage induced

  14. Programable Driver for Voltage-Controlled Oscillators

    Science.gov (United States)

    Fowler, L. E.; Mcneil, J. A.

    1985-01-01

    Electronically programable read-only memory (EPROM) and digital-to-analog converter provide customized time-varying voltage for frequency modulation. Voltage used to modulate IMPATT oscillator that serves as microwave pump for solid-state maser in low-noise amplifier. EPROM simple to tailor voltage waveform to suit characteristics of given maser. Digital information for waveform programed into EPROM chip; digital-to-analog converter reads information and produces corresponding analog wave. Principle readily adapted to other applications.

  15. Generator of ultrashort megavolt voltage pulses

    CERN Document Server

    Zheltov, K A; Shalimanov, V F

    2002-01-01

    Paper describes approx 3 ns duration and > 1 MW amplitude voltage pulse generator under high-ohmic (approx 450 Ohm) load. Generator comprises pulse transformer with magnetized core, as well as, resonance tuned circuit of high-voltage solenoid and accumulating spaces of a shaping line containing, moreover, spark gap to switch charge in transmitting line. Paper contains the results of voltage measuring in generator basic units

  16. Investigation of pulsed voltage limiters characteristics

    Directory of Open Access Journals (Sweden)

    Karimov A. V.

    2012-06-01

    Full Text Available A new method for measuring the voltage limit is offered. It has been designed to measure high-power pulsed current of voltage limiters. The error of this method is half as much as the error of the known method of direct measurement. The investigation of dependence of power capability of single-crystal and double-crystal voltage limiters and of the pulsed operation time on pulse duration.

  17. Low-Voltage Switched-Capacitor Circuits

    DEFF Research Database (Denmark)

    Bidari, E.; Keskin, M.; Maloberti, F.

    1999-01-01

    Switched-capacitor stages are described which can function with very low (typically 1 V) supply voltages, without using voltage boosting or switched op-amps. Simulations indicate that high performance may be achieved using these circuits in filter or data converter applications.......Switched-capacitor stages are described which can function with very low (typically 1 V) supply voltages, without using voltage boosting or switched op-amps. Simulations indicate that high performance may be achieved using these circuits in filter or data converter applications....

  18. Characterisation of the VELO High Voltage System

    CERN Document Server

    Rakotomiaramanana, B; Eklund, L

    2008-01-01

    The high voltage system supplies the bias voltage to the 88 silicon sensors which comprise the LHCb Vertex Locator (VELO). This note describes the results of the tests which have been performed on the hardware of the high voltage system of the VELO. Each individual test detailed in this note corresponds to a specific requirement of the system. These requirements arise primarily from ensuring the safety of the silicon sensors and the quality of the data taken from the VELO modules. The tests performed are in four categories: normal operation of the high voltage system; vercation of its stability under operation; discussion of its behaviour in failure modes; and details of operation at low voltage. Noteworthy issues, identified through the tests, include the behaviour of the high voltage modules at voltages below 9V, the current limit that can be applied during ramping of the voltage, and the speed with which the voltage is cut during failures of the system. The results of these tests provide high confidence th...

  19. Characterisation of the VELO High Voltage System

    CERN Document Server

    Rakotomiaramanana, B; Parkes, C; Eklund, L

    2008-01-01

    The high voltage system supplies the bias voltage to the 88 silicon sensors which comprise the LHCb Vertex Locator (VELO). This note describes the results of the tests which have been performed on the hardware of the high voltage system of the VELO. Each individual test detailed in this note corresponds to a specific requirement of the system. These requirements arise primarily from ensuring the safety of the silicon sensors and the quality of the data taken from the VELO modules. The tests performed are in four categories: normal operation of the high voltage system; verification of its stability under operation; discussion of its behaviour in failure modes; and details of operation at low voltage. Noteworthy issues, identified through the tests, include the behaviour of the high voltage modules at voltages below 9V, the current limit that can be applied during ramping of the voltage, and the speed with which the voltage is cut during failures of the system. The results of these tests provide high confidence...

  20. Microprocessor-controlled, programmable ramp voltage generator

    Energy Technology Data Exchange (ETDEWEB)

    Hopwood, J.

    1978-11-01

    A special-purpose voltage generator has been developed for driving the quadrupole mass filter of a residual gas analyzer. The generator is microprocessor-controlled with desired ramping parameters programmed by setting front-panel digital thumb switches. The start voltage, stop voltage, and time of each excursion are selectable. A maximum of five start-stop levels may be pre-selected for each program. The ramp voltage is 0 to 10 volts with sweep times from 0.1 to 999.99 seconds.

  1. Magnetoelectric voltage coefficients of magnetoelectric composites

    Institute of Scientific and Technical Information of China (English)

    WAN Yong-ping; ZHONG Zheng; QIU Jin-hao

    2006-01-01

    The magnetoelectric(ME) effect of the particulate magnetostrictive/piezoelectric composite was theoretically studied. The dependence of the ME voltage coefficients on the material properties of the magnetostrictive phase was discussed. The permittivity,permeability and the elastic modulus of the magnetostrictive phase generally have obvious influences on the ME voltage coefficients. The magnetostrictive phase with a large permittivity,large permeability or stiffer modulus will respectively contribute to the higher ME voltage coefficients. For a certain kind of piezoelectric matrix,the ME voltage coefficients can be improved to some extent by choosing those magnetostrictive materials with large permittivity,permeability or high elastic modulus.

  2. Maximum permissible voltage of YBCO coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Wen, J.; Lin, B.; Sheng, J.; Xu, J.; Jin, Z. [Department of Electrical Engineering, Shanghai Jiao Tong University, Shanghai (China); Hong, Z., E-mail: zhiyong.hong@sjtu.edu.cn [Department of Electrical Engineering, Shanghai Jiao Tong University, Shanghai (China); Wang, D.; Zhou, H.; Shen, X.; Shen, C. [Qingpu Power Supply Company, State Grid Shanghai Municipal Electric Power Company, Shanghai (China)

    2014-06-15

    Highlights: • We examine three kinds of tapes’ maximum permissible voltage. • We examine the relationship between quenching duration and maximum permissible voltage. • Continuous I{sub c} degradations under repetitive quenching where tapes reaching maximum permissible voltage. • The relationship between maximum permissible voltage and resistance, temperature. - Abstract: Superconducting fault current limiter (SFCL) could reduce short circuit currents in electrical power system. One of the most important thing in developing SFCL is to find out the maximum permissible voltage of each limiting element. The maximum permissible voltage is defined as the maximum voltage per unit length at which the YBCO coated conductors (CC) do not suffer from critical current (I{sub c}) degradation or burnout. In this research, the time of quenching process is changed and voltage is raised until the I{sub c} degradation or burnout happens. YBCO coated conductors test in the experiment are from American superconductor (AMSC) and Shanghai Jiao Tong University (SJTU). Along with the quenching duration increasing, the maximum permissible voltage of CC decreases. When quenching duration is 100 ms, the maximum permissible of SJTU CC, 12 mm AMSC CC and 4 mm AMSC CC are 0.72 V/cm, 0.52 V/cm and 1.2 V/cm respectively. Based on the results of samples, the whole length of CCs used in the design of a SFCL can be determined.

  3. Inductive voltage divider modeling in Matlab

    Science.gov (United States)

    Andreev, S. A.; Kim, V. L.

    2017-01-01

    Inductive voltage dividers have the most appropriate metrological characteristics on alternative current and are widely used for converting physical signals. The model of a double-decade inductive voltage divider was designed with the help of Matlab/Simulink. The first decade is an inductive voltage divider with balanced winding, the second decade is a single-stage inductive voltage divider. In the paper, a new transfer function algorithm was given. The study shows errors and differences that appeared between the third degree reduced model and a twenty degree unreduced model. The obtained results of amplitude error differ no more than by 7 % between the reduced and unreduced model.

  4. Development of a voltage scanner of chopper

    CERN Document Server

    Shen Guan Ren; LiShengLi; WangQuanXing; Wu Long Cheng

    2001-01-01

    Development of voltage sweeper of chopper with CPNG are introduced. Voltage sweeper is one of important key parts of chopper. Two years working prove that it is stable and reliable. Its main technology performance save: sine wave frequency: 750 kHz +- 20 Hz; total distortion: 65 Db; output voltage (V-V): 0->=4000 V; the error7 W; voltage supply: 220V AC +-10%, 50 +- 1 Hz; total power supply: <100W; Work temperature range: 0 - 40 degree; Stability in long time <=1%

  5. Excitation of voltage oscillations in an induction voltage adder

    Directory of Open Access Journals (Sweden)

    Nichelle Bruner

    2009-07-01

    Full Text Available The induction voltage adder is an accelerator architecture used in recent designs of pulsed-power driven x-ray radiographic systems such as Sandia National Laboratories’ Radiographic Integrated Test Stand (RITS, the Atomic Weapons Establishment’s planned Hydrus Facility, and the Naval Research Laboratory’s Mercury. Each of these designs relies on magnetic insulation to prevent electron loss across the anode-cathode gap in the vicinity of the adder as well as in the coaxial transmission line. Particle-in-cell simulations of the RITS adder and transmission line show that, as magnetic insulation is being established during a pulse, some electron loss occurs across the gap. Sufficient delay in the cavity pulse timings provides an opportunity for high-momentum electrons to deeply penetrate the cavities of the adder cells where they can excite radio-frequency resonances. These oscillations may be amplified in subsequent gaps, resulting in oscillations in the output power. The specific modes supported by the RITS-6 accelerator and details of the mechanism by which they are excited are presented in this paper.

  6. A new three-dimensional electromechanical impedance model for an embedded dual-PZT transducer

    Science.gov (United States)

    Wang, Dansheng; Li, Zhi; Zhu, Hongping

    2016-07-01

    In the past twenty years, the electromechanical (EM) impedance technique has been investigated extensively in the mechanical, aviation and civil engineering fields. Many different EM impedance models have been proposed to characterize the interaction between the surface-bonded PZT transducer and the host structure. This paper formulates a new three-dimensional EM impedance model characterizing the interaction between an embedded circle dual-PZT transducer and the host structure based on the effective impedance concept. The proposed model is validated by experimental results from a group of smart cement cubes, in which three circle dual-PZT transducers are embedded respectively. In addition, a new EM impedance measuring method for the dual-PZT transducer is also introduced. In the measuring method, only a common signal generator and an oscilloscope are needed, by which the exciting and receiving voltage signals are obtained respectively. Combined with fast Fourier transform the EM impedance signatures of the dual-PZT transducers are obtained.

  7. Microchip dual-frequency Nd:YAG laser with tunable frequency difference

    Science.gov (United States)

    Chen, Xiangyi; Cheng, Lijun; Zhao, Changming; Zhang, Haiyang; Yang, Suhui

    2015-08-01

    40 mW of dual-frequency power from a microchip diode-pumped solid-state Nd:YAG laser is presented. A coupled cavity is used as a mode selector and enforce a single frequency oscillation. An electro-optic crystal and a pair of quarter-wave plates are used to obtain dual frequency oscillation, respectively. By changing the applied voltage and the angle between two fast axes of the wave plates, the frequency difference of the two frequency is changed. Using dual quarter-wave plate method, we obtained 40 mW of dual-frequency laser output when the absorbed pumping power was 690 mW.

  8. Alexander Duals of Multipermutohedron Ideals

    Indian Academy of Sciences (India)

    Ajay Kumar; Chanchal Kumar

    2014-02-01

    An Alexander dual of a multipermutohedron ideal has many combinatorial properties. The standard monomials of an Artinian quotient of such a dual correspond bijectively to some -parking functions, and many interesting properties of these Artinian quotients are obtained by Postnikov and Shapiro (Trans. Am. Math. Soc. 356 (2004) 3109–3142). Using the multigraded Hilbert series of an Artinian quotient of an Alexander dual of multipermutohedron ideals, we obtained a simple proof of Steck determinant formula for enumeration of -parking functions. A combinatorial formula for all the multigraded Betti numbers of an Alexander dual of multipermutohedron ideals are also obtained.

  9. Near-Threshold Computing and Minimum Supply Voltage of Single-Rail MCML Circuits

    Directory of Open Access Journals (Sweden)

    Ruiping Cao

    2014-01-01

    Full Text Available In high-speed applications, MOS current mode logic (MCML is a good alternative. Scaling down supply voltage of the MCML circuits can achieve low power-delay product (PDP. However, the current almost all MCML circuits are realized with dual-rail scheme, where the NMOS configuration in series limits the minimum supply voltage. In this paper, single-rail MCML (SRMCML circuits are described, which can avoid the devices configuration in series, since their logic evaluation block can be realized by only using MOS devices in parallel. The relationship between the minimum supply voltage of the SRMCML circuits and the model parameters of MOS transistors is derived, so that the minimum supply voltage can be estimated before circuit designs. An MCML dynamic flop-flop based on SRMCML is also proposed. The optimization algorithm for near-threshold sequential circuits is presented. A near-threshold SRMCML mode-10 counter based on the optimization algorithm is verified. Scaling down the supply voltage of the SRMCML circuits is also investigated. The power dissipation, delay, and power-delay products of these circuits are carried out. The results show that the near-threshold SRMCML circuits can obtain low delay and small power-delay product.

  10. Power supply and impedance matching to drive technological radio-frequency plasmas with customized voltage waveforms.

    Science.gov (United States)

    Franek, James; Brandt, Steven; Berger, Birk; Liese, Martin; Barthel, Matthias; Schüngel, Edmund; Schulze, Julian

    2015-05-01

    We present a novel radio-frequency (RF) power supply and impedance matching to drive technological plasmas with customized voltage waveforms. It is based on a system of phase-locked RF generators that output single frequency voltage waveforms corresponding to multiple consecutive harmonics of a fundamental frequency. These signals are matched individually and combined to drive a RF plasma. Electrical filters are used to prevent parasitic interactions between the matching branches. By adjusting the harmonics' phases and voltage amplitudes individually, any voltage waveform can be approximated as a customized finite Fourier series. This RF supply system is easily adaptable to any technological plasma for industrial applications and allows the commercial utilization of process optimization based on voltage waveform tailoring for the first time. Here, this system is tested on a capacitive discharge based on three consecutive harmonics of 13.56 MHz. According to the Electrical Asymmetry Effect, tuning the phases between the applied harmonics results in an electrical control of the DC self-bias and the mean ion energy at almost constant ion flux. A comparison with the reference case of an electrically asymmetric dual-frequency discharge reveals that the control range of the mean ion energy can be significantly enlarged by using more than two consecutive harmonics.

  11. SYNTHESIS OF VOLTAGES OF UNIFORM PWM IN TIME REGULATION

    Directory of Open Access Journals (Sweden)

    A. G. Stryzhniou

    2014-01-01

    Full Text Available The article describes a process of synthesis and qualitative assessment of the harmonic composition of voltages of multiple and single PWM pulses in time regulation, being, along with amplitude, frequency and phase method, one of control methods of an asynchronous motor. The main point of time regulation is that a pause after any two single PWM pulses with different polarity or after any two groups of multiple PWM pulses with different polarity changes during a process of regulation. Feature of time regulation is that a motor has fast response in the range of small-signal of control and good linearity of speed-torque characteristics in the whole control range. Analytical expressions of parameters of PWM pulses ai and ti are obtained which allow to simplify considerably a process of formation and implementation of time regulation using tabular or indexed-tabular methods. These expressions allow not only to define voltage amplitude of  harmonic but also to perform qualitative assessment of harmonic composition of output voltages at time regulation. It is specified that harmonic frequencies wi = w0/q change in inverse proportion to magnitude of parameter q during a process of regulation and there is a replacement of a fundamental frequency by frequencies of higher harmonics.The offered approach allows to synthesize voltage of uniform single and multiple PWM pulses and to perform their comparative and qualitative analysis and the obtained expressions can be used at modeling of AC motor work. Voltage of multiple PWM pulses which is formed using stepped reference voltage with even quantity of steps in a half period and a pause on a zero level has the best parameters by criterion of a minimum of harmonic components and a maximum of a factor of anharmonicity Kнс at time regulation.

  12. Prevalence of Victimization in Patients With Dual Diagnosis.

    Science.gov (United States)

    de Waal, Marleen Maria; Dekker, Jacobus Johannes Maria; Goudriaan, Anna Emma

    2017-01-01

    The purpose of this study was to determine the prevalence of victimization in patients with co-occurring mental health and substance use disorders (dual diagnosis) and compare them to the general population. In this cross-sectional survey study conducted in the Netherlands, 9 different types of victimization (e.g., physical assault) were assessed with the Safety Monitor in patients with dual diagnosis (n = 243) and a sample of the general population (n = 10,865). Chi-square tests were used to compare patients with a weighted sample of the general population. Compared to the general population, patients with dual diagnosis were more likely to have been a victim of violence (60% vs. 11%), property crime (58% vs. 30%), and vandalism (21% vs. 14%) in the year preceding the assessment. Threats, sexual assault, physical assault, robbery, bicycle theft, other theft, and vandalism were more prevalent in patients with dual diagnosis compared to the general population. Car theft was more prevalent in the general population. The risk of burglary did not differ significantly between groups. Patients with dual diagnosis are highly prone to victimization. In patients with severe mental illness, victimization is associated with psychopathology, substance use, homelessness, and engagement in criminal activity. Future research is necessary to explore underlying mechanisms in patients with dual diagnosis and develop interventions to reduce their vulnerability for victimization.

  13. Dual massive gravity

    Energy Technology Data Exchange (ETDEWEB)

    Morand, Kevin, E-mail: Kevin.Morand@lmpt.univ-tours.fr [Laboratoire de Mathematiques et Physique Theorique, Universite Francois-Rabelais Tours, Federation Denis Poisson - CNRS, Parc de Grandmont, 37200 Tours (France); Solodukhin, Sergey N., E-mail: Sergey.Solodukhin@lmpt.univ-tours.fr [Laboratoire de Mathematiques et Physique Theorique, Universite Francois-Rabelais Tours, Federation Denis Poisson - CNRS, Parc de Grandmont, 37200 Tours (France)

    2012-08-29

    The linearized massive gravity in three dimensions, over any maximally symmetric background, is known to be presented in a self-dual form as a first order equation which encodes not only the massive Klein-Gordon type field equation but also the supplementary transverse-traceless conditions. We generalize this construction to higher dimensions. The appropriate dual description in d dimensions, additionally to a (non-symmetric) tensor field h{sub {mu}{nu}}, involves an extra rank-(d-1) field equivalently represented by the torsion rank-3 tensor. The symmetry condition for h{sub {mu}{nu}} arises on-shell as a consequence of the field equations. The action principle of the dual theory is formulated. The focus has been made on four dimensions. Solving one of the fields in terms of the other and putting back in the action one obtains two other equivalent formulations of the theory in which the action is quadratic in derivatives. In one of these representations the theory is formulated entirely in terms of a rank-2 non-symmetric tensor h{sub {mu}{nu}}. This quadratic theory is not identical to the Fierz-Pauli theory and contains the coupling between the symmetric and antisymmetric parts of h{sub {mu}{nu}}. Nevertheless, the only singularity in the propagator is the same as in the Fierz-Pauli theory so that only the massive spin-2 particle is propagating. In the other representation, the theory is formulated in terms of the torsion rank-3 tensor only. We analyze the conditions which follow from the field equations and show that they restrict to 5 degrees of freedom thus producing an alternative description to the massive spin-2 particle. A generalization to higher dimensions is suggested.

  14. A Synchrophasor Based Optimal Voltage Control Scheme with Successive Voltage Stability Margin Improvement

    Directory of Open Access Journals (Sweden)

    Heng-Yi Su

    2016-01-01

    Full Text Available This paper proposes an optimal control scheme based on a synchronized phasor (synchrophasor for power system secondary voltage control. The framework covers voltage stability monitoring and control. Specifically, a voltage stability margin estimation algorithm is developed and built in the newly designed adaptive secondary voltage control (ASVC method to achieve more reliable and efficient voltage regulation in power systems. This new approach is applied to improve voltage profile across the entire power grid by an optimized plan for VAR (reactive power sources allocation; therefore, voltage stability margin of a power system can be increased to reduce the risk of voltage collapse. An extensive simulation study on the IEEE 30-bus test system is carried out to demonstrate the feasibility and effectiveness of the proposed scheme.

  15. Effects of Electrode Material on the Voltage of a Tree-Based Energy Generator.

    Directory of Open Access Journals (Sweden)

    Zhibin Hao

    Full Text Available The voltage between a standing tree and its surrounding soil is regarded as an innovative renewable energy source. This source is expected to provide a new power generation system for the low-power electrical equipment used in forestry. However, the voltage is weak, which has caused great difficulty in application. Consequently, the development of a method to increase the voltage is a key issue that must be addressed in this area of applied research. As the front-end component for energy harvesting, a metal electrode has a material effect on the level and stability of the voltage obtained. This study aimed to preliminarily ascertain the rules and mechanisms that underlie the effects of electrode material on voltage. Electrodes of different materials were used to measure the tree-source voltage, and the data were employed in a comparative analysis. The results indicate that the conductivity of the metal electrode significantly affects the contact resistance of the electrode-soil and electrode-trunk contact surfaces, thereby influencing the voltage level. The metal reactivity of the electrode has no significant effect on the voltage. However, passivation of the electrode materials markedly reduces the voltage. Suitable electrode materials are demonstrated and recommended.

  16. High-Mixed-Voltage Analog and RF Circuit Techniques for Nanoscale CMOS

    CERN Document Server

    Mak, Pui-In

    2012-01-01

    This book presents high-/mixed-voltage analog and radio frequency (RF) circuit techniques for developing low-cost multistandard wireless receivers in nm-length CMOS processes.  Key benefits of high-/mixed-voltage RF and analog CMOS circuits are explained, state-of-the-art examples are studied, and circuit solutions before and after voltage-conscious design are compared. Three real design examples are included, which demonstrate the feasibility of high-/mixed-voltage circuit techniques.    Provides a valuable summary and real case studies of the state-of-the-art in high-/mixed-voltage circuits and systems; Includes novel high-/mixed-voltage analog and RF circuit techniques – from concept to practice; Describes the first high-voltage-enabled mobile-TVRF front-end in 90nm CMOS and the first mixed-voltage full-band mobile-TV Receiver in 65nm CMOS; Demonstrates the feasibility of high-/mixed-voltage circuit techniques with real design examples.  

  17. Impact of distributed generators on the power loss and voltage profile of sub-transmission network

    Directory of Open Access Journals (Sweden)

    A.S.O. Ogunjuyigbe

    2016-05-01

    Full Text Available This paper presents the impact of distributed generator (DG on the power loss and voltage profile of sub-transmission network at different penetration levels (PLs. The various DG technologies are modeled based on their electrical output characteristics. Voltage profile index which allows a single value to represent how well the voltage matches the ideal value is developed. The index allows a fair comparison of the voltage profile obtained from different scenarios. The extent to which DGs affect power losses and voltage profile depend on the type of DG technology, PL and the location in which the DG is connected to the grid. The integration of DGs reduces power losses on the network, however, as the PL increases, the power losses begin to increase. A PL of 50–75% is achieved on 69 kV voltage level and 25–50% penetration on 13.8 kV voltage level without an increase in the power loss. Also more DG can be integrated into the network at point of common connection of higher voltage level compared to the low voltage level.

  18. Evaluation of the Voltage Support Strategies for the Low Voltage Grid Connected PV

    DEFF Research Database (Denmark)

    Demirok, Erhan; Sera, Dezso; Teodorescu, Remus

    2010-01-01

    PVs. In order to increase PV penetration level further, new voltage support control functions for individual inverters are required. This paper investigates distributed reactive power regulation and active power curtailment strategies regarding the development of PV connection capacity by evaluation......Admissible range of grid voltage is one of the strictest constraints for the penetration of distributed photovoltaic (PV) generators especially connection to low voltage (LV) public networks. Voltage limits are usually fulfilled either by network reinforcements or limiting of power injections from...

  19. Comparison Of Modified Dual Ternary Indexing And Multi-Key Hashing Algorithms For Music Information Retrieval

    OpenAIRE

    2010-01-01

    In this work we have compared two indexing algorithms that have been used to index and retrieve Carnatic music songs. We have compared a modified algorithm of the Dual ternary indexing algorithm for music indexing and retrieval with the multi-key hashing indexing algorithm proposed by us. The modification in the dual ternary algorithm was essential to handle variable length query phrase and to accommodate features specific to Carnatic music. The dual ternary indexing algorithm is ...

  20. Musical expertise has minimal impact on dual task performance

    OpenAIRE

    Cocchini, Gianna; Filardi, Maria Serena; Crhonkova, Marcela; Halpern, Andrea

    2017-01-01

    Studies investigating effect of practice on dual task performance have yielded conflicting findings, thus supporting different theoretical accounts about the organization of attentional resources when tasks are performed simultaneously. Because practice has been proven to reduce the demand of attention for the trained task, the impact of long-lasting training on one task is an ideal way to better understand the mechanisms underlying dual task decline in performance. \\ud \\ud Our study compared...