**Commenced**in January 2007

**Frequency:**Monthly

**Edition:**International

**Paper Count:**3960

# Search results for: constant current density

##### 3960 The Photon-Drag Effect in Cylindrical Quantum Wire with a Parabolic Potential

**Authors:**
Hoang Van Ngoc,
Nguyen Thu Huong,
Nguyen Quang Bau

**Abstract:**

Using the quantum kinetic equation for electrons interacting with acoustic phonon, the density of the constant current associated with the drag of charge carriers in cylindrical quantum wire by a linearly polarized electromagnetic wave, a DC electric field and a laser radiation field is calculated. The density of the constant current is studied as a function of the frequency of electromagnetic wave, as well as the frequency of laser field and the basic elements of quantum wire with a parabolic potential. The analytic expression of the constant current density is numerically evaluated and plotted for a specific quantum wires GaAs/AlGaAs to show the dependence of the constant current density on above parameters. All these results of quantum wire compared with bulk semiconductors and superlattices to show the difference.

**Keywords:**
Photon-drag effect,
constant current density,
quantum wire,
parabolic potential.

##### 3959 Current Distribution and Cathode Flooding Prediction in a PEM Fuel Cell

**Authors:**
A. Jamekhorshid,
G. Karimi,
I. Noshadi,
A. Jahangiri

**Abstract:**

**Keywords:**
Current distribution,
Flooding,
Hydrogen energysystem,
PEM fuel cell.

##### 3958 Effect of Current Density, Temperature and Pressure on Proton Exchange Membrane Electrolyser Stack

**Authors:**
Na Li,
Samuel Simon Araya,
Søren Knudsen Kær

**Abstract:**

This study investigates the effects of operating parameters of different current density, temperature and pressure on the performance of a proton exchange membrane (PEM) water electrolysis stack. A 7-cell PEM water electrolysis stack was assembled and tested under different operation modules. The voltage change and polarization curves under different test conditions, namely current density, temperature and pressure, were recorded. Results show that higher temperature has positive effect on overall stack performance, where temperature of 80 ℃ improved the cell performance greatly. However, the cathode pressure and current density has little effect on stack performance.

**Keywords:**
PEM electrolysis stack,
current density,
temperature,
pressure.

##### 3957 Heating of High-Density Hydrogen by High- Current Arc Radiation

**Authors:**
A. V. Budin,
Ph. G. Rutberg,
M. E. Pinchuk,
A. A. Bogomaz,
V. Yu. Svetova

**Abstract:**

**Keywords:**
High-density hydrogen heating by high-current
electric arc.

##### 3956 A Comparative Study on Optimized Bias Current Density Performance of Cubic ZnB-GaN with Hexagonal 4H-SiC Based Impatts

**Authors:**
Arnab Majumdar,
Srimani Sen

**Abstract:**

In this paper, a vivid simulated study has been made on 35 GHz Ka-band window frequency in order to judge and compare the DC and high frequency properties of cubic ZnB-GaN with the existing hexagonal 4H-SiC. A flat profile p^{+}pnn^{+} DDR structure of impatt is chosen and is optimized at a particular bias current density with respect to efficiency and output power taking into consideration the effect of mobile space charge also. The simulated results obtained reveals the strong potentiality of impatts based on both cubic ZnB-GaN and hexagonal 4H-SiC. The DC-to-millimeter wave conversion efficiency for cubic ZnB-GaN impatt obtained is 50% with an estimated output power of 2.83 W at an optimized bias current density of 2.5×10^{8} A/m^{2}. The conversion efficiency and estimated output power in case of hexagonal 4H-SiC impatt obtained is 22.34% and 40 W respectively at an optimum bias current density of 0.06×10^{8} A/m^{2}.

**Keywords:**
Cubic ZnB-GaN,
hexagonal 4H-SiC,
Double drift impatt diode,
millimeter wave,
optimized bias current density,
wide band gap semiconductor.

##### 3955 PSRR Enhanced LDO Regulator Using Noise Sensing Circuit

**Authors:**
Min-ju Kwon,
Chae-won Kim,
Jeong-yun Seo,
Hee-guk Chae,
Yong-seo Koo

**Abstract:**

In this paper, we presented the LDO (low-dropout) regulator which enhanced the PSRR by applying the constant current source generation technique through the BGR (Band Gap Reference) to form the noise sensing circuit. The current source through the BGR has a constant current value even if the applied voltage varies. Then, the noise sensing circuit, which is composed of the current source through the BGR, operated between the error amplifier and the pass transistor gate of the LDO regulator. As a result, the LDO regulator has a PSRR of -68.2 dB at 1k Hz, -45.85 dB at 1 MHz and -45 dB at 10 MHz. the other performance of the proposed LDO was maintained at the same level of the conventional LDO regulator.

**Keywords:**
LDO regulator,
noise sensing circuit,
current reference,
pass transistor.

##### 3954 A Simplified Approach for Load Flow Analysis of Radial Distribution Network

**Authors:**
K. Vinoth Kumar,
M.P. Selvan

**Abstract:**

**Keywords:**
constant current load,
constant impedance load,
constant power load,
forward–backward sweep,
load flow
analysis,
radial distribution system.

##### 3953 Discrete Estimation of Spectral Density for Alpha Stable Signals Observed with an Additive Error

**Authors:**
R. Sabre,
W. Horrigue,
J. C. Simon

**Abstract:**

This paper is interested in two difficulties encountered in practice when observing a continuous time process. The first is that we cannot observe a process over a time interval; we only take discrete observations. The second is the process frequently observed with a constant additive error. It is important to give an estimator of the spectral density of such a process taking into account the additive observation error and the choice of the discrete observation times. In this work, we propose an estimator based on the spectral smoothing of the periodogram by the polynomial Jackson kernel reducing the additive error. In order to solve the aliasing phenomenon, this estimator is constructed from observations taken at well-chosen times so as to reduce the estimator to the field where the spectral density is not zero. We show that the proposed estimator is asymptotically unbiased and consistent. Thus we obtain an estimate solving the two difficulties concerning the choice of the instants of observations of a continuous time process and the observations affected by a constant error.

**Keywords:**
Spectral density,
stable processes,
aliasing,
periodogram.

##### 3952 Compressive Strength and Capillary Water Absorption of Concrete Containing Recycled Aggregate

**Authors:**
Yeşim Tosun,
Remzi Şahin

**Abstract:**

**Keywords:**
Capillary water absorption,
compressive strength,
density,
recycled concrete aggregates.

##### 3951 Influence of Paralleled Capacitance Effect in Well-defined Multiple Value Logical Level System with Active Load

**Authors:**
Chih Chin Yang,
Yen Chun Lin,
Hsiao Hsuan Cheng

**Abstract:**

**Keywords:**
Capacitance,
Logical level,
Constant current source

##### 3950 Enhancement of Pulsed Eddy Current Response Based on Power Spectral Density after Continuous Wavelet Transform Decomposition

**Authors:**
A. Benyahia,
M. Zergoug,
M. Amir,
M. Fodil

**Abstract:**

The main objective of this work is to enhance the Pulsed Eddy Current (PEC) response from the aluminum structure using signal processing. Cracks and metal loss in different structures cause changes in PEC response measurements. In this paper, time-frequency analysis is used to represent PEC response, which generates a large quantity of data and reduce the noise due to measurement. Power Spectral Density (PSD) after Wavelet Decomposition (PSD-WD) is proposed for defect detection. The experimental results demonstrate that the cracks in the surface can be extracted satisfactorily by the proposed methods. The validity of the proposed method is discussed.

**Keywords:**
NDT,
pulsed eddy current,
continuous wavelet transform,
Mexican hat wavelet mother,
defect detection,
power spectral density.

##### 3949 Characterization of Pure Nickel Coatings Fabricated under Pulse Current Conditions

**Authors:**
M. Sajjadnejad,
H. Omidvar,
M. Javanbakht,
A. Mozafari

**Abstract:**

**Keywords:**
Current density,
Duty cycle,
Microstructure,
Nickel,
Pulse frequency.

##### 3948 The Influence of Low Power Microwave Radiation on the Growth Rate of Listeria Monocytogenes

**Authors:**
Renzo Carta,
Francesco Desogus

**Abstract:**

**Keywords:**
Growth rate constant,
irradiated environment,
Listeria monocytogenes,
microwaves,
plug flow reactor.

##### 3947 The Mechanical and Electrochemical Properties of DC-Electrodeposited Ni-Mn Alloy Coating with Low Internal Stress

**Authors:**
Chun-Ying Lee,
Kuan-Hui Cheng,
Mei-Wen Wu

**Abstract:**

**Keywords:**
DC plating,
internal stress,
leveling power,
Ni-Mn
coating.

##### 3946 Recovery of Copper and DCA from Simulated Micellar Enhanced Ultrafiltration (MEUF)Waste Stream

**Authors:**
Chuan-Kun Liu,
Chi-Wang Li

**Abstract:**

**Keywords:**
metal recovery,
MEUF waste,
surfactant,
electroplating.

##### 3945 Improved Small-Signal Characteristics of Infrared 850 nm Top-Emitting Vertical-Cavity Lasers

**Authors:**
Ahmad Al-Omari,
Osama Khreis,
Ahmad M. K. Dagamseh,
Abdullah Ababneh,
Kevin Lear

**Abstract:**

*f*

_{-3dB}) of 14 GHz and a resonance frequency (

*f*

_{R}) of 9.5 GHz at a bias current density (

*J*) of only 4.3 kA/cm

_{bias}^{2}, which corresponds to an improved

*f*

_{-3dB}

^{2}/

*J*ratio of 44 GHz

_{bias}^{2}/kA/cm

^{2}. At higher and lower bias current densities, the

*f*

_{-3dB}

^{2}/

*J*ratio decreased to about 30 GHz

_{bias}^{2}/kA/cm

^{2}and 18 GHz

^{2}/kA/cm

^{2}, respectively. Examination of the analogue modulation response demonstrated that the presented VCSELs displayed a steady

*f*

_{-3dB}/

*f*

_{R}ratio of 1.41±10% over the whole range of the bias current (1.3

*I*

_{th}to 6.2

*I*

_{th}). The devices also demonstrated a maximum modulation bandwidth (

*f*

_{-3dB max}) of more than 16 GHz at a bias current less than the industrial bias current standard for reliability by 25%.

**Keywords:**
Current density,
High-speed VCSELs,
Modulation bandwidth,
Small-Signal Characteristics,
Thermal impedance,
Vertical-cavity surface-emitting lasers.

##### 3944 Study of Temperature Difference and Current Distribution in Parallel-Connected Cells at Low Temperature

**Authors:**
Sara Kamalisiahroudi,
Jun Huang,
Zhe Li,
Jianbo Zhang

**Abstract:**

Two types of commercial cylindrical lithium ion batteries (Panasonic 3.4 Ah NCR-18650B and Samsung 2.9 Ah INR-18650), were investigated experimentally. The capacities of these samples were individually measured using constant current-constant voltage (CC-CV) method at different ambient temperatures (-10°C, 0°C, 25°C). Their internal resistance was determined by electrochemical impedance spectroscopy (EIS) and pulse discharge methods. The cells with different configurations of parallel connection NCR-NCR, INR-INR and NCR-INR were charged/discharged at the aforementioned ambient temperatures. The results showed that the difference of internal resistance between cells much more evident at low temperatures. Furthermore, the parallel connection of NCR-NCR exhibits the most uniform temperature distribution in cells at -10°C, this feature is quite favorable for the safety of the battery pack.

**Keywords:**
Batteries in parallel connection,
internal resistance,
low temperature,
temperature difference,
current distribution.

##### 3943 The Light-Effect in Cylindrical Quantum Wire with an Infinite Potential for the Case of Electrons: Optical Phonon Scattering

**Authors:**
Hoang Van Ngoc,
Nguyen Vu Nhan,
Nguyen Quang Bau

**Abstract:**

The light-effect in cylindrical quantum wire with an infinite potential for the case of electrons, optical phonon scattering, is studied based on the quantum kinetic equation. The density of the direct current in a cylindrical quantum wire by a linearly polarized electromagnetic wave, a DC electric field, and an intense laser field is calculated. Analytic expressions for the density of the direct current are studied as a function of the frequency of the laser radiation field, the frequency of the linearly polarized electromagnetic wave, the temperature of system, and the size of quantum wire. The density of the direct current in cylindrical quantum wire with an infinite potential for the case of electrons – optical phonon scattering is nonlinearly dependent on the frequency of the linearly polarized electromagnetic wave. The analytic expressions are numerically evaluated and plotted for a specific quantum wire, GaAs/GaAsAl.

**Keywords:**
The light-effect,
cylindrical quantum wire with an infinite potential,
the density of the direct current,
electrons - optical phonon scattering.

##### 3942 Controlling Water Temperature during the Electrocoagulation Process Using an Innovative Flow Column-Electrocoagulation Reactor

**Authors:**
Khalid S. Hashim,
Andy Shaw,
Rafid Alkhaddar,
Montserrat Ortoneda Pedrola

**Abstract:**

**Keywords:**
Water temperature,
flow column,
electrocoagulation.

##### 3941 Influence of Crystal Orientation on Electromechanical Behaviors of Relaxor Ferroelectric P(VDF-TrFE-CTFE) Terpolymer

**Authors:**
Qing Liu,
Jean-Fabien Capsal,
Claude Richard

**Abstract:**

In this current contribution, authors are dedicated to investigate influence of the crystal lamellae orientation on electromechanical behaviors of relaxor ferroelectric Poly (vinylidene fluoride –trifluoroethylene -chlorotrifluoroethylene) (P(VDF-TrFE-CTFE)) films by control of polymer microstructure, aiming to picture the full map of structure-property relationship. In order to define their crystal orientation films, terpolymer films were fabricated by solution-casting, stretching and hot-pressing process. Differential scanning calorimetry, impedance analyzer, and tensile strength techniques were employed to characterize crystallographic parameters, dielectric permittivity, and elastic Young’s modulus respectively. In addition, large electrical induced out-of-plane electrostrictive strain was obtained by cantilever beam mode. Consequently, as-casted pristine films exhibited surprisingly high electrostrictive strain 0.1774% due to considerably small value of elastic Young’s modulus although relatively low dielectric permittivity. Such reasons contributed to large mechanical elastic energy density. Instead, due to 2 folds increase of elastic Young’s modulus and less than 50% augmentation of dielectric constant, fullycrystallized film showed weak electrostrictive behavior and mechanical energy density as well. And subjected to mechanical stretching process, Film C exhibited stronger dielectric constant and out-performed electrostrictive strain over Film B because edge-on crystal lamellae orientation induced by uniaxially mechanical stretch. Hot-press films were compared in term of cooling rate. Rather large electrostrictive strain of 0.2788% for hot-pressed Film D in quenching process was observed although its dielectric permittivity equivalent to that of pristine as-casted Film A, showing highest mechanical elastic energy density value of 359.5 J/m3. In hot-press cooling process, dielectric permittivity of Film E saw values at 48.8 concomitant with ca.100% increase of Young’s modulus. Films with intermediate mechanical energy density were obtained.

**Keywords:**
Crystal orientation,
electrostrictive strain,
mechanical energy density,
permittivity,
relaxor ferroelectric.

##### 3940 The Analysis of Photoconductive Semiconductor Switch Operation in the Frequency of 10 GHz

**Authors:**
Morteza Fathipour,
Seyed Nasrolah Anousheh,
Kaveh Ghiafeh Davoudi,
Vala Fathipour

**Abstract:**

**Keywords:**
Band X,
Gallium-Arsenide,
Mixed mode,
PCSS,
Photoconductivity.

##### 3939 Density Functional Calculations of 27Al, 11B,and 14N and NQR Parameters in the (6, 0) BN_AlN Nanotube Junction

**Authors:**
Morteza Farahani,
Ahmad Seif,
Asadallah Boshra,
Hossein Aghaie

**Abstract:**

Density functional theory (DFT) calculations were performed to calculate aluminum-27, boron-11, and nitrogen-14 quadrupole coupling constant (CQ) in the representative considered model of (6, 0) boron nitride-aluminum nitride nanotube junction (BN-AlNNT) for the first time. To this aim, 1.3 nm length of BNAlN consisting of 18 Al, 18 B, and 36 N atoms was selected where the end atoms capped by hydrogen atoms. The calculated CQ values for optimized BN-AlNNT system reveal different electrostatic environment in the mentioned system. The calculations were performed using the Gaussian 98 package of program.

**Keywords:**
Nanotube Junction,
Density functional,
Nuclear Quadrupole Resonance.

##### 3938 Study of the Transport of Multivalent Metal Cations through Cation-Exchange Membranes by Electrochemical Impedance Spectroscopy

**Authors:**
V. Pérez-Herranz,
M. Pinel,
E. M. Ortega,
M. García-Gabaldón

**Abstract:**

In the present work, Electrochemical Impedance Spectrocopy (EIS) is applied to study the transport of different metal cations through a cation-exchange membrane. This technique enables the identification of the ionic-transport characteristics and to distinguish between different transport mechanisms occurring at different current density ranges. The impedance spectra are dependent on the applied dc current density, on the type of cation and on the concentration. When the applied dc current density increases, the diameter of the impedance spectra loops increases because all the components of membrane system resistance increase. The diameter of the impedance plots decreases in the order of Na(I), Ni(II) and Cr(III) due to the increased interactions between the negatively charged sulfonic groups of the membrane and the cations with greater charge. Nyquist plots are shifted towards lower values of the real impedance, and its diameter decreases with the increase of concentration due to the decrease of the solution resistance.

**Keywords:**
Ion-exchange Membranes,
Electrochemical
Impedance Espectroscopy,
Multivalent Metal Cations.

##### 3937 Behavior of Current in a Semiconductor Nanostructure under Influence of Embedded Quantum Dots

**Authors:**
H. Paredes Gutiérrez,
S. T. Pérez-Merchancano

**Abstract:**

Motivated by recent experimental and theoretical developments, we investigate the influence of embedded quantum dot (EQD) of different geometries (lens, ring and pyramidal) in a double barrier heterostructure (DBH). We work with a general theory of quantum transport that accounts the tight-binding model for the spin dependent resonant tunneling in a semiconductor nanostructure, and Rashba spin orbital to study the spin orbit coupling. In this context, we use the second quantization theory for Rashba effect and the standard Green functions method. We calculate the current density as a function of the voltage without and in the presence of quantum dots. In the second case, we considered the size and shape of the quantum dot, and in the two cases, we worked considering the spin polarization affected by external electric fields. We found that the EQD generates significant changes in current when we consider different morphologies of EQD, as those described above. The first thing shown is that the current decreases significantly, such as the geometry of EQD is changed, prevailing the geometrical confinement. Likewise, we see that the current density decreases when the voltage is increased, showing that the quantum system studied here is more efficient when the morphology of the quantum dot changes.

**Keywords:**
Quantum semiconductors,
nanostructures,
quantum dots,
spin polarization.

##### 3936 A Study on the Effects of Thermodynamic Nonideality and Mass Transfer on Multi-phase Hydrodynamics Using CFD Methods

**Authors:**
Irani,
Mohammad,
Bozorgmehry Boozarjomehry,
Ramin,
Pishvaie Mahmoud Reza,
Ahmad Tavasoli

**Abstract:**

Considering non-ideal behavior of fluids and its effects on hydrodynamic and mass transfer in multiphase flow is very essential. Simulations were performed that takes into account the effects of mass transfer and mixture non-ideality on hydrodynamics reported by Irani et al. In this paper, by assuming the density of phases to be constant and Raullt-s law instead of using EOS and fugacity coefficient definition, respectively for both the liquid and gas phases, the importance of non-ideality effects on mass transfer and hydrodynamic behavior was studied. The results for a system of octane/propane (T=323 K, P =445 kpa) also indicated that the assumption of constant density in simulation had major role to diverse from experimental data. Furthermore, comparison between obtained results and the previous report indicated significant differences between experimental data and simulation results with more ideal assumptions.

**Keywords:**
Multiphase flow,
VOF,
mass transfer,
Raoult's law,
non-ideal thermodynamic,
CFD.

##### 3935 Development of a Brain Glutamate Microbiosensor

**Authors:**
Kartika S. Hamdan,
Zainiharyati M. Zain,
Mohamed I. A. Halim,
Jafri M. Abdullah,
Robert D. O'Neill

**Abstract:**

This work attempts to improve the permselectivity of poly-ortho-phenylenediamine (PPD) coating for glutamate biosensor applications on Pt microelectrode, using constant potential amperometry and cyclic voltammetry. Percentage permeability of the modified PPD microelectrode was carried out towards hydrogen peroxide (H2O2) and ascorbic acid (AA) whereas permselectivity represents the percentage interference by AA in H2O2 detection. The 50-μm diameter Pt disk microelectrode showed a good permeability value toward H2O2 (95%) and selectivity against AA (0.01%) compared to other sizes of electrode studied here. The electrode was further modified with glutamate oxidase (GluOx) that was immobilized and cross linked with glutaraldehyde (GA, 0.125%), resulting in Pt/PPD/GluOx-GA electrode design. The maximum current density Jmax and apparent Michaelis constant, KM, obtained on Pt/PPD/GluOx-GA electrodes were 48 μA cm-2 and 50 μM, respectively. The linear region slope (LRS) was 0.96 μA cm-2 mM-1. The detection limit (LOD) for glutamate was 3.0 ± 0.6 μM. This study shows a promising glutamate microbiosensor for brain glutamate detection.

**Keywords:**
Brain,
Glutamate,
Microbiosensor.

##### 3934 A Comparative Studies on Methanesulfonic and p-Touluene Sulfonic Acid Incorporated Polyacrylamide Gel Polymer Electrolyte for Tin-Air Battery

**Authors:**
S. Sumathi,
V. Sethuprakhash,
W. J. Basirun

**Abstract:**

This study was focused on polymer electrolytes containing methanesulfonic acid (MSA) and p-toluene sulfonic acid (pTSA) mixed with polyacrylamide (PAAm) respectively. Impedance Spectroscopy technique has been employed to compare the ionic conductivity of these polymer electrolytes. The ionic conductivity of the PAAm hydrogel electrolytes increase upon adding the sulfonic acids. Ionic conductivity of PAAm-pTSA is higher than PAAm-MSA. The electrochemical performance evaluations were done with the tin-air cells discharge at zero current for 30minutes and at constant current density of 2.5, 5, 7.5, 10, 12.5 and 15mA/cm^{2}. The tin-air cell of PAAm-MSA produce higher specific discharge capacity compared to PAAm-pTSA. Open-circuit voltage measurement revealed a higher voltage for tin-air cell of PAAm-MSA which is 1.27V.

**Keywords:**
Methane sulfonic acid,
polyacrylamide,
polymer gel electrolytes,
p-toluene sulfonic acid.

##### 3933 Orthogonal Polynomial Density Estimates: Alternative Representation and Degree Selection

**Authors:**
Serge B. Provost,
Min Jiang

**Abstract:**

**Keywords:**
kernel density estimation,
orthogonal polynomials,
moment-based methodologies,
density approximation.

##### 3932 Close Loop Controlled Current Nerve Locator

**Authors:**
H. A. Alzomor,
B. K. Ouda,
A. M. Eldeib

**Abstract:**

Successful regional anesthesia depends upon precise location of the peripheral nerve or nerve plexus. Locating peripheral nerves is preferred to be done using nerve stimulation. In order to generate a nerve impulse by electrical means, a minimum threshold stimulus of current “rheobase” must be applied to the nerve. The technique depends on stimulating muscular twitching at a close distance to the nerve without actually touching it. Success rate of this operation depends on the accuracy of current intensity pulses used for stimulation .In this paper, we will discuss a circuit and algorithm for closed loop control for the current, theoretical analysis and test results is discussed and results is compared to previous techniques.

**Keywords:**
Close Loop Control,
Constant Current,
Nerve Locator.

##### 3931 Fuzzy Logic Controller Based Shunt Active Filter with Different MFs for Current Harmonics Elimination

**Authors:**
Shreyash Sinai Kunde,
Siddhang Tendulkar,
Shiv Prakash Gupta,
Gaurav Kumar,
Suresh Mikkili

**Abstract:**

One of the major power quality concerns in modern times is the problem of current harmonics. The current harmonics is caused due to the increase in non-linear loads which is largely dominated by power electronics devices. The Shunt active filtering is one of the best solutions for mitigating current harmonics. This paper describes a fuzzy logic controller based (FLC) based three Phase Shunt active Filter to achieve low current harmonic distortion (THD) and Reactive power compensation. The performance of fuzzy logic controller is analysed under both balanced sinusoidal and unbalanced sinusoidal source condition. The above controller serves the purpose of maintaining DC Capacitor Voltage constant. The proposed shunt active filter uses hysteresis current controller for current control of IGBT based PWM inverter. The simulation results of model in Simulink MATLAB reveals satisfying results.

**Keywords:**
Shunt active filter,
Current harmonics,
Fuzzy logic controller,
Hysteresis current controller.