bluuebunny/crossref_metadata_2025 huggingface dataset:
Crystal structure and electrochemical properties of LiFe1−xZnxPO4 (x ≤ 1.0)
Authors: Zhao Yanming , Chen Ling , Chen Xiren , Kuang Quan , Dong Youzhong
Published: October 2011

A series of LiFe1−xZnxPO4 (0.0 ≤ x ≤ 1.0) compounds were prepared by solid-state reaction. Effects of the substitution of Zn for Fe on crystal structure and electrochemical properties of LiFe1−xZnxPO4 were investigated. The results show that single-phase regions of LiFe1−xZnxPO4 with orthorhombic (space group Pmna) and monoclinic (Cc) structures were found for the compounds with low Zn (or high Fe) contents of 0.0 ≤ x ≤ 0.30 and high Zn (or low Fe) contents of 0.90 ≤ x ≤ 1.0, respectively. The LiFe1−xZnxPO4 compounds with medium Zn (or Fe) contents of 0.35 ≤ x ≤ 0.80 are two-phase mixtures containing both the orthorhombic and the monoclinic phases. Systematic variations of unit-cell parameters a, b, c, and volume V with the Zn content determined by X-ray diffraction have also been obtained. Our electrochemical study show that the conductivity of LiFe1−xZnxPO4 increases by almost 2 orders of magnitude from 2.13 × 10−9 to 1.27 × 10−7 Scm−1 as the Zn content increasing from x = 0 to 0.3. The initial specific capacity decreases and the cycle performance increase with increasing Zn-doping content in the four orthorhombic LiFe1−xZnxPO4 compounds. Among the four LiFe1−xZnxPO4 compounds, LiFe0.8Zn0.2PO4 has the highest capacity retentions after 6 to 20 cycles and the capacity retention is 93.7% after 20 cycles, even though the initial discharge specific capacity of LiFe0.8Zn0.2PO4 is lower than those of LiFeZnPO4 and LiFe0.9Zn0.1PO4. LiFe0.7Zn0.3PO4 has the highest capacity retention of 97% after 20 cycles.
Structure of melt-quenched AgIn3Te5
Authors: Rangasami C. , Malar P. , Osipowicz T. , Jain Mahaveer K. , Kasiviswanathan S.
Published: October 2011

Polycrystalline AgIn3Te5synthesized by melt-quench technique has been analyzed using proton induced X-ray emission (PIXE), X-ray diffraction (XRD), and selected area electron diffraction. PIXE analysis yielded the content of Ag, In, and Te, respectively, to be 9.76%, 31.18%, and 59.05% by weight. Structure refinement was carried out considering those space groups from I- and P-type tetragonal systems which possess4symmetry and preserve the anion sublattice arrangement of the chalcopyrite structure (space group:I42d) as well. The results showed that AgIn3Te5synthesized by melt-quench method crystallizes with P-type tetragonal structure (space group:P42c; unit-cell parametersa= 6.2443(8) andc= 12.5058(4) Å), the presence of which was corroborated by selected area electron diffraction studies.
High-resolution synchrotron X-ray powder diffraction study of bis(2-methylimidazolyl)-zinc, C8H10N4Zn (ZIF-8)
Authors: Wong-Ng W. , Kaduk J. A. , Espinal L. , Suchomel M. R. , Allen A. J. , Wu H.
Published: October 2011

The family of zeolitic imidazolate framework (ZIF) compounds is efficient sorbent materials that can be used for catalytic, ion exchange, gas storage, and gas separation applications. A high-resolution reference X-ray powder diffraction pattern for one of the ZIF members, bis(2-methylimidazolyl)-zinc, C8H10N4Zn (commonly known as ZIF-8), was determined using synchrotron diffraction data obtained at the Advanced Photon Source (APS) in Argonne, IL. The sample was confirmed to be cubic I-43m, with a = 17.01162(6) Å, V = 4932.08 Å3, and Z = 12. The reference X-ray powder diffraction pattern has been submitted for inclusion in the Powder Diffraction File (PDF).
X-ray powder diffraction data for N-[4-(aminocarbonyl)phenyl]-4- [2-[1-[[(2,3-dihydro-2-oxo-1H-benzimidazol-5-yl)amino]carbonyl]-2-oxopropyl]diazenyl]-benzamide, a β-form of pigment yellow 181
Authors: Maixner J. , Pažout R. , Cibulková J. , Kratochvíl B.
Published: October 2011

X-ray powder diffraction data, unit-cell parameters and space group for the β-form of pigment yellow 181, C25H21N7O5, are reported [a= 22.556(6) Å,b= 4.9684(9) Å,c= 21.318(6) Å,β= 109.492(4)°, unit-cell volumeV= 2252,1 Å3,Z= 4, space groupP21/c]. All measured lines were indexed and are consistent with theP21/c space group. No detectable impurities were observed.
Immediate Regression of Leukoaraiosis after Carotid Artery Revascularization
Authors: Chuang Yu-Ming , Huang Kuo-Lun , Chang Yeu-Jhy , Chang Chien-Hung , Chang Ting-Yu , Wu Tai-Cheng , Wong Ho-Fai , Liu Shan-Jin , Lee Tsong-Hai
Published: October 2011

Background: Leukoaraiosis (LA) affects cognition after stroke and reversal of LA may improve cognitive performance. We aimed to determine the impact of cerebral perfusion and circle of Willis (CoW) flow patterns on the extent of LA after carotid artery revascularization. Methods: LA was scored on fluid-attenuated inversion recovery magnetic resonance (MR) images at the levels of the centrum semiovale and frontal horns in both cerebral hemispheres of 62 contiguous patients (men/women = 38/24, mean age = 63.2 ± 8.4 years, range 44–82) before and after unilateral carotid artery revascularization. The pre- and poststenting differences in LA scores, CoW flow pattern on MR angiography, and MR perfusion parameters were analyzed. Results: The total LA score decreased from 9.87 ± 0.65 to 8.33 ± 0.72 after stenting (p = 0.03). The CoW was complete in 21 subjects and incomplete in 41 subjects. The incomplete CoW group had a higher preoperative LA load and higher cerebral interhemispheric asymmetry index, both of which decreased significantly postoperatively. Conclusions: CoW anomalies may contribute to LA in patients with carotid artery stenosis, and restoration of cerebral perfusion by carotid artery revascularization can reduce LA severity.
Effects of a Single Mannitol Bolus on Cerebral Hemodynamics in Intracerebral Hemorrhage: A Transcranial Doppler Study
Authors: Vicenzini E. , Ricciardi M.C. , Zuco C. , Sirimarco G. , Di Piero V. , Lenzi G.L.
Published: October 2011

Background: Mannitol infusion is widely used in clinical practice to reduce perilesional edema in intracerebral hemorrhage (ICH), though no controlled studies have yet provided evidence of its effects on clinical outcome or on cerebral blood flow impairment following the event. The aim of our study was to evaluate blood flow velocity changes in the middle cerebral arteries (MCA) after a mannitol bolus in patients with ICH. Methods: Transcranial Doppler bilateral monitoring was performed for 90 min in 20 patients with ICH, during 100 ml mannitol bolus i.v. administration. The MCA mean flow velocities (MFVs) and pulsatility index (PI) were recorded. Results: When the ‘healthy’ and the ‘affected’ hemispheres were compared, we observed higher MCA MFV and lower PI on the affected side than on the contralateral side, both at baseline and during the experiment. After the mannitol bolus, we observed a significant MFV increase, starting at the end of the infusion and lasting longer than 60 min in the MCA on the affected side alone. The PI increased after mannitol administration on the healthy side alone. Conclusions: A single bolus of mannitol modified cerebral hemodynamics in our patients with ICH, increasing flow velocities on the affected MCA. This effect may be a consequence of reduced edema in the perilesional areas. The increased PI on the unaffected side may be indicative of preserved pulsatility in the healthy hemisphere.
The Potential of Social Identity for Equilibrium Selection
Authors: Chen Roy , Chen Yan
Published: October 2011

When does a common group identity improve efficiency in coordination games? To answer this question, we propose a group-contingent social preference model and derive conditions under which social identity changes equilibrium selection. We test our predictions in the minimum-effort game in the laboratory under parameter configurations which lead to an inefficient low-effort equilibrium for subjects with no group identity. For those with a salient group identity, consistent with our theory, we find that learning leads to ingroup coordination to the efficient high-effort equilibrium. Additionally, our theoretical framework reconciles findings from a number of coordination game experiments. (JEL C71, C91, D71)
Alterations in cell maturity and serum survival factors may modulate neutrophil numbers in sickle cell disease
Authors: Almeida Camila Bononi , Favero Maria Emilia , Pereira-Cunha Fernanda Gonçalves , Lorand-Metze Irene , Saad Sara T Olalla , Costa Fernando Ferreira , Conran Nicola
Published: October 2011

Leukocytes are known to exacerbate inflammatory and vaso-occlusive processes in sickle cell disease (SCD). The aim of this study was to determine whether alterations in neutrophil maturity and/or cell-death modulating factors in the circulation contribute to the increased leukocyte counts and leukocyte survival observed in SCD. The maturity of circulating neutrophils from healthy control individuals (CON), SCD and SCD patients on hydroxyurea therapy (SCDHU) was determined immunophenotypically. Serum factors affecting neutrophil apoptosis (determined by annexin V-binding) were analyzed by culturing control neutrophils (CON neutrophils) with pooled serum from CON, SCD and SCDHU individuals. Immunophenotypic characterization of neutrophils suggested a slight, but significant, increase in the circulation of immature neutrophils in SCD. While SCD neutrophils cultured in the presence of CON serum presented delayed apoptosis, unexpectedly, the culture of CON neutrophils with SCD serum significantly augmented apoptosis and caspase-9 activity. Inhibition of the activity of serum interleukin-8, a neutrophil-apoptosis-inhibiting cytokine, significantly increased SCD serum-induced CON neutrophil apoptosis, indicating that SCD serum may have both apoptotic and antiapoptotic properties. The decreased maturity of SCD neutrophils observed is suggestive of an accelerated immigration of leukocytes from the bone marrow to the circulating pool that may contribute to an increase in cell survival, subject to modulation by a complex balance of both anti- and proapoptotic factors contained in the circulation of SCD individuals.
Heart failure mice exhibit decreased gastric emptying and intestinal absorption
Authors: Addisu Anteneh , Gower William R , Serrano Maria , Villarreal Daniel , Dietz John R
Published: October 2011

Our recent study showed that intravenously administered B-type natriuretic peptide (BNP) decreases gastric emptying and intestinal absorption in mice. We aimed to test whether acute myocardial injury and heart failure have similar effects. Wild-type (WT) and natriuretic peptide receptor type A (NPR-A) knockout (KO) mice underwent cryoinfarction (myocardial infarction [MI]) of the left ventricle (LV) versus sham. LV dysfunction was confirmed by echocardiography. Percent gastric emptying and intestinal absorption were measured and analyzed one and two weeks after infarction, by gavage feeding the mice with fluorescein-isothiocyanate-dextran. Ejection fraction was 48 ± 3% versus 64 ± 2% ( P < 0.05) and fractional shortening was 24 ± 2% versus 35 ± 2% ( P < 0.01), MI versus sham, respectively. BNP levels (pg/mL) were 4292 ± 276 one week after MI versus 105 ± 11 in sham ( n = 5, P < 0.05) and 1964 ± 755 two weeks after MI ( n = 5, P < 0.05). Gastric emptying was significantly decreased, 68 ± 6% in MI versus 89 ± 3% in sham ( n = 5, P < 0.05) one week after MI and 82 ± 0.5% versus 98 ± 0.4%, MI versus sham ( n = 5, P < 0.05), two weeks post-MI. Absorption, measured in relative plasma fluorescence units in WT mice, was 350 ± 79 in MI versus 632 ± 121 in sham ( n = 6, P < 0.05). KO mice did not show a significant difference in emptying or absorption compared with sham. These findings suggest that MI and LV dysfunction decrease gastric emptying and absorption in mice through a mechanism that involves NPR-A.
Fifth-Generation Digital Immunoassay for Prostate-Specific Antigen by Single Molecule Array Technology
Authors: Wilson David H , Hanlon David W , Provuncher Gail K , Chang Lei , Song Linan , Patel Purvish P , Ferrell Evan P , Lepor Herbert , Partin Alan W , Chan Dan W , Sokoll Lori J , Cheli Carol D , Thiel Robert P , Fournier David R , Duffy David C
Published: October 2011

BACKGROUND

Measurement of prostate-specific antigen (PSA) in prostate cancer patients following radical prostatectomy (RP) has been hindered by the limit of quantification of available assays. Because radical prostatectomy removes the tissue responsible for PSA production, postsurgical PSA is typically undetectable with current assay methods. Evidence suggests, however, that more sensitive determination of PSA status following RP could improve assessment of patient prognosis and response to treatment and better target secondary therapy for those who may benefit most. We developed an investigational digital immunoassay with a limit of quantification 2 logs lower than current ultrasensitive third-generation PSA assays.

METHODS

We developed reagents for a bead-based ELISA for use with high-density arrays of femtoliter-volume wells. Anti-PSA capture beads with immunocomplexes and associated enzyme labels were singulated within the wells of the arrays and interrogated for the presence of enzymatic product. We characterized analytical performance, compared its accuracy with a commercially available test, and analyzed longitudinal serum samples from a pilot study of 33 RP patients.

RESULTS

The assay exhibited a functional sensitivity (20% interassay CV) <0.05 pg/mL, total imprecision <10% from 1 to 50 pg/mL, and excellent agreement with the comparator method. All RP samples were well within the assay measurement capability. PSA concentrations following surgery were found to be predictive of prostate cancer recurrence risk over 5 years.

CONCLUSIONS

The robust 2-log improvement in limit of quantification relative to current ultrasensitive assays and the validated analytical performance of the assay allow for accurate assessment of PSA status after RP.
Correlates of social awareness in the visual prosody of growing children
Authors: Swerts Marc
Published: October 2011

This article focuses on how growing children use prosody for communicative purposes. Prosody refers to the set of expressive features that do not so much determine what speakers say, but rather how they say it. It includes both auditory features, such as intonation and tempo, and visual features, such as facial expressions. Our central hypothesis is that children, as they grow older, become more socially aware — a process which is reflected in the way they express themselves in prosody. To this end, we present the results of three studies that focus on how children use such features (1) to mark their level of uncertainty, (2) to signal a positive or negative emotion, and (3) to show whether they are being truthful or not. All the studies use a game-based experimental paradigm that is especially suited for analyses of child behaviour. The approach combines controlled elicitations of spontaneous interactions with perception tests that explore how children's expressions are being interpreted. Results of such studies are relevant for pedagogical and diagnostic purposes, and will lead to improvements in child-directed communication systems.
Spanish nasal assimilation revisited: A cross-dialect electropalatographic study
Authors: Kochetov Alexei , Colantoni Laura
Published: October 2011

This study employs electropalatography to investigate the implementation of nasal assimilation in two Spanish dialects (Argentinian and Cuban) that differ in the realization of word-final nasals as alveolar or velar. 5 speakers of Argentian and 3 speakers of Cuban Spanish were presented with various utterances containing nasals followed by labial, coronal, and dorsal stops and fricatives under two stress conditions. Results revealed that place assimilation of nasals was consistently accompanied by stricture assimilation. The process was generally categorical, that is, the final alveolar or velar nasal adopted the articulation of the following consonant. Nasal + fricative sequences, however, showed a somewhat different behavior: occasional blocking of nasal assimilation before non-coronals, consistent gradient nasal assimilation before coronals (Argentinian), or categorical/gradient strengthening of post-nasal obstruents (Cuban). Overall, the results are largely consistent with Honorof's (Articulatory gestures and Spanish nasal assimilation, Yale University Ph.D. dissertation, 1999) study of Peninsular Spanish and together provide evidence for dialect-specific grammars of assimilation, which nevertheless share certain general principles of gestural organization.
Application of Hilbert-Huang Transform to Inertial Profile Verification: A Laboratory Approach
Authors: Lee Mei-Hui , Chou Chia-Pei
Published: October 2011

Past studies have shown that most inertial profiler verification procedures are conducted through repeated profile measurements on test sections with known profiles. This type of an evaluation can erroneously affect inertial profile results because of non-controllable parameters such as profiler equipment, analytical software, and operator variables. In order to improve the accuracy of inertial profiler certifications, a laboratory simulation method for inertial profilers was developed. This method uses an apparatus that combines sinusoidal vertical displacements of various frequencies and amplitude levels. As a result, errors attributed to operator variables are excluded, and errors induced by a profiler and software are further identified. This study utilizes the Hilbert-Huang transform (HHT) to improve the laboratory verification process by reducing measurement noise and creating a more stable signal in different frequency-amplitude combinations. The noise source is also identified by applying the HHT, which can provide guidance on further profiler verification enhancements.
Manifestation of ray chaos in optical cavities
Authors: Shinohara Susumu , Harayama Takahisa
Published: October 2011

The correspondence between ray and wave descriptions for twodimensional
chaotic open billiards describing optical cavities is reviewed.
Focusing on the stadium-shaped cavity, which is well-known
for its fully chaotic ray dynamics, we show how ray chaos is manifested
in emission patterns, or eigenfunctions of resonances (decaying
eigenmodes). The flux phase-space distribution is introduced, which
not only enables one to understand the relation between ray dynamics
and emission directionality, but also provides a suitable stage to study
the ray-wave correspondence. We observe intrinsic localization phenomenon
in each resonance, which causes discrepancies with the ray
description. Nonetheless, we demonstrate that the average of many
low-loss resonances reproduces the ray description very well, where one
can clearly observe that signature of ray chaos (i.e., long-term effects
of stretching and folding) is embedded in resonance eigenfunctions.
Simulation, optimization, and fabrication of optical micro microresonator based lasers and filters, and coupling to radial or tangential waveguides
Authors: Huang Yingyan , Li Xiangyu , Ou Fang , Ho Seng-Tiong
Published: October 2011

Microdisk, Microring, Microcylinder, and various curvilinear-shape
optical resonators with sizes from submicron to hundreds of microns
have become a widely used technology. We refer to them collectively as
optical microresonators. These optical microresonators can be used as
highly compact tunable optical filters integrated on chip. They can also
be used to form wavelength-scale optical cavities for realizing microcavity
lasers and various microcavity devices. There are few systematic
studies of the limitations of these microresonators. Knowing their limitations
is important for various practical applications. We first review
the various progresses in these optical microresonators, followed by a
discussion of the main factors affecting the cavity Q factor of these
microresonators. To understand radiation loss, we show a numerically
accurate method to compute the radiation loss using conformal transformation.
We discuss how to simulate lasing properties of these optical
microresonators by using a multi-level multi-electron Finite-Difference
Time-Domain (MLME FDTD) quantum model for the semiconductor
medium. We then discuss how to compute radiation loss and scattering
loss using a FDTD method based on an active-lasing approach
and to compare the results to the conformal transformation results.
Lastly, we address the important question of how to optimize output
coupling of the lasing light in these optical resonators utilizing either
a conventional tangential waveguide coupling method or a novel radial
waveguide coupling method.
Application of genetic algorithms to an inverse field problem in magnetic fluid dynamics
Authors: Kuilekov Milko , Ziolkowski Marek , Brauer Hartmut
Published: October 2011

The purpose of the present work is to study whether genetic algorithms can solve an inverse field problem in magnetic fluid dynamics (MFD) efficiently. We have investigated how the interface between two fluids of different conductivity in a highly simplified model of an aluminum electrolysis cell can be reconstructed by means of external magnetic field measurements. The knowledge of the interface deformation can be used to prevent undesired instabilities in aluminum reduction cells .
Rejection of PSK interference in DS-SS/PSK system using adaptive transversal filter with conditional response recalculation
Authors: Nikolic Zorica , Dimitrijevic Bojan , Milosevic Nenad
Published: October 2011

PSK interference rejection using complex adaptive filter with conditional response recalculation in DS-SS/PSK system is considered in this paper. New adaptive filter decreases error probability for several orders of magnitude when compared to the standard adaptive transversal filter.
Finite impulse response digital filters with integer multipliers
Authors: Stojanovic Vidosav , Minic Sinisa
Published: October 2011

In this paper, a family of non-recursive digital filters will be described in which all multipliers are small integers. It is shown that this practical advantage is only available if some rather severe restrictions on the locations of z-plane poles and zeros are accepted. These restrictions have the further advantage that all filters of the family display pure linear-phase characteristics, imposing a pure transmission delay on all frequency components of an input signal.
Inductance of cylindrical coil
Authors: Cividjian G.A. , Dolan A. , Pãduraru N.
Published: October 2011

The cylindrical coreless and bar core coils are used in instrument transformers and many other electromagnetic devices. In the paper, using the separation of variables an analytical formula for the leakage inductance of thin cylindrical coil with unsaturated core is deduced, assuming a simplified path for the frontal flux. The results are compared with well-known experimental data and data resulting from FEM models.
Interaction between lf electric fields and biological bodies
Authors: Ceselkoska Vesna
Published: October 2011

In this paper the Equivalent electrodes method is used for electric field calculation in the proximity of the various biological subjects exposed to an electric field in the LF range. Several results of the electric field intensity on the body surface and numerous graphical results for equipotential and equienergetic curves are presented.
Sensitivity analysis of electromagnetic quantities in time domain by means of fem
Authors: Gawrylczyk Konstanty , Kugler Mateusz
Published: October 2011

Sensitivity analysis belongs to the most important tools in optimization theory. It determines the dependence of global or local electromagnetic quantities on geometrical and physical parameters expressed in the form of an objective function. For several objective functions the sensitivity may be directly calculated differentiating the objective function versus one of material or geometric parameters. Such approach needs large computational effort, especially while evaluating in time domain. This paper presents effective methods for computing of sensitivity of nodal potentials in finite elements versus perturbations in conductivity of analyzed model in time domain. Derived equations are based on the method of stiffness and mass matrices derivative and Tellegen?s theorem known from circuit theory and have been expanded on field theory. Numerical example presented in the paper shows sensitivity of voltage induced in measurement coil versus variation of electrical conductivity in single finite element as function of time. The proposed methods calculate the sensitivity versus all finite elements in area of analysis at once. On the basis of sensitivity information the iterative algorithm for identification of shape and conductivity distribution of material flaws could be applied.
Dielectric body with arbitrary shaped and positioned cavity in homogeneous transversal electric field
Authors: Peric Mirjana
Published: October 2011

This paper presents an application of Charge Simulation Method for calculation of the electric field strength and the potential in the arbitrary shaped and positioned cavity of the dielectric body. The dielectric body can also have an arbitrary, but known shape. Several examples of the dielectric body with the cavity are presented. The whole system is in the homogeneous transverse electrical field. The results obtained in this way have been compared to the results obtained by the program?s packages: Bela 1.0 and Quickfield 4.2 (Student?s Edition).
Dynamic characteristics of a bitable linear actuator with moving permanent magnet
Authors: Yatchev Ivan , Hinov Krastio , Gueorgiev Vultchan
Published: October 2011

The dynamic characteristics of an ax symmetrical linear actuator with axially magnetized moving permanent magnet are obtained using combined field and circuit approach. The magnetic field of the actuator has been analyzed using the finite element method over a current-displacement sampling grid. Two field analyses are carried out for each point of the grid - one for the real system and one for the system where the permanent magnet is considered as a soft magnetic body. For each point of the grid, data for the total flux linkage, electromagnetic force and the coil inductance are extracted from the magnetic field analysis. These data are approximated by bicubic spline functions, which are employed in the solution of the system of ordinary differential equations of the electrical circuit and the mechanical motion. Results are obtained for the time variations of the coil current, mover displacement, mover velocity and electromagnetic force. The results for the current and displacement are verified experimentally.
Comparative analysis of two gain-and offset-compensated four-phase switched-capacitor integrators based on the second-order Adams-Bashworth’s integration method
Authors: Radev Nikolay , Ivanov Kantcho
Published: October 2011

Gain-and offset-compensated (GOC) modifications of four-phase inverting and no inverting switched-capacitor integrators based on the second-order Adams-Bashworth?s integration method are presented. Analytical expressions for the gain, phase and offset voltage errors are derived and compared with the corresponding errors of the earlier ones compensated integrators. The two pairs of GOC integrators are used as building blocks of a band pass biquad. The performances of the resulting filters are also compared.
Efficient modeling of chiral media using SCN-TLM method
Authors: Yaich M.I. , Khalladi Mohsine , Essaaidi M.
Published: October 2011

An efficient approach allowing to include linear bi-isotropic chiral materials in time-domain transmission line matrix (TLM) calculations by employing recursive evaluation of the convolution of the electric and magnetic fields and susceptibility functions is presented. The new technique consists to add both voltage and current sources in supplementary stubs of the symmetrical condensed node (SCN) of the TLM method. In this article, the details and the complete description of this approach are given. A comparison of the obtained numerical results with those of the literature reflects its validity and efficiency.
Low-frequency plane wave diffraction on a two-layer grating
Authors: Dlabac Tatijana , Filipovic Dragan
Published: October 2011

In this paper the problem of TE and TM plane wave diffraction from a two-layer grating in low-frequency case is presented. The problem is solved using the network model. Numerical results for the reflection coefficient of the lowest (n=0) mode versus frequency are given and compared to available results from literature.
Automated reasoning-alternative methods
Authors: Perovic Aleksandar , Stefanovic Nedeljko , Milosevic Milos , Ilic Dejan
Published: October 2011

Our main goal is to describe a potential usage of the interpretation method (i.e. formal representation of one first order theory into another) together with quantifier elimination procedures developed in the GIS.
A family of IIR two-band orthonormal QMF filter banks
Authors: Damjanovic Sanja , Milic Ljiljana
Published: October 2011

The design and characteristics of orthonormal two-band QMF filter banks, with perfect reconstruction and linear phase properties, are considered in this paper. The analysis and synthesis filter banks are implemented using all pass filters. Filters in the synthesis bank are ant causal and unstable filters and the block processing technique and an appropriate causal filter are applied for their real time application. The generated filter banks characteristics and the finite block length influence of the block processing technique applied for ant causal filtering are illustrated for a rectangular input signal case. The corresponding wavelet and scaling functions, generated after five iterations of the analysis bank in a low pass branch, are shown.
Determination of the neutron flux in the reactor zones with the strong neutron absorption and leakage
Authors: Ljubenov Vladan , Milosevic Miodrag
Published: October 2011

The procedures for the numerical and experimental determination of the neutron flux in the zones with the strong neutron absorption and leakage are described in this paper. Numerical procedure is based on the application of the SCALE-4.4a code system where the Dancoff factors are determined by the VEGA2DAN code. Two main parts of the experimental methodology are measurement of the activity of irradiated foils and determination of the averaged neutron absorption cross-section in the foils by the SCALE-4.4a calculation procedure. The proposed procedures have been applied for the determination of the neutron flux in the internal neutron converter used with the RB reactor core configuration number 114.
Adaptive vector quantization in SVD MIMO system backward link with limited number of active sub channels
Authors: Ivanis Predrag , Drajic Dusan
Published: October 2011

This paper presents combination of Channel Optimized Vector Quantization based on LBG algorithm and sub channel power allocation for MIMO systems with Singular Value Decomposition and limited number of active sub channels. Proposed algorithm is designed to enable maximal throughput with bit error rate bellow some tar- get level in case of backward channel capacity limitation. Presence of errors effect in backward channel is also considered.
A practical fast acting control scheme for fuzzy logic-based voltage stabilization control
Authors: El-Kholy E.E. , El-Sabbe A. , Shokralla S.S. , El-Hefnawy Nancy
Published: October 2011

This paper presents a simplified control model for stabilizing a load voltage using a switched reactor in parallel with a fixed capacitor of static VAR compensator. Two IGBT?s are used to control the reactance of the switched reactor. A uniform pulse width modulation is used for controlling the two switches. The compensator has a simple control circuit and structure. A complete modeling and numerical simulation for the proposed systems are presented. A high speed Digital Signal Processor is used for implementing proportional integral (PI) and fuzzy load voltage controllers. Experimental results indicate the superiority of fuzzy logic control over the conventional proportional-integral control method. Simulation results are reported and proved to be in good agreement with the relevant experimental results.
Possible solution of parallel FIR filter structure
Authors: Petrovic Predrag
Published: October 2011

In this paper, a parallel form FIR adaptive filter structure with RLS (Recursive Least Squares) type adaptive algorithm is proposed. The proposed parallel form FIR structure consists of a recursive orthogonal transform stage and sparse FIR sub filters operating in parallel. The adaptive algorithm used to update coefficient vector of the sparse filters is implemented by using modified Hopfield networks. This structure implements the RLS-type adaptive algorithm, without an explicit matrix inversion avoiding numerical instability problems. Simulation results which show the desirable features of proposed structure are given.
Reduction of operational amplifiers finite gain effects in switched-capacitor biquads
Authors: Radev Nikolay , Ivanov Kantcho
Published: October 2011

A combined approach for reducing the errors in the pole frequency f p, the pole Q - factor Qp and the magnitude at the pole frequency Hp, of switched capacitor biquads is presented. First, the conventional integrators in the biquads are replaced with gain-and offset-compensated integrators. Next, the errors ? ?p / ?p, ? Qp / Qp and ? Hp / Hp are minimized by modifying three capacitances: two feedback capacitances and feed forward capacitance. The effectiveness of this approach is demonstrated by designing a band pass biquad.
The correlation of processes of crystallization and changes of free electron density amorphous alloy powder Co80Ni20
Authors: Maricic Aleksa , Ristic Momcilo
Published: October 2011

Great attention is being given today to investigations on the capabilities and structural changes of amorphous and nanocrystal materials. Structural changes of the amorphous cobalt and nickel alloy powder obtained by electrochemical deposition were investigated in this paper. The crystallization process, as determined by the DSC method, occurred in two steps. The temperature dependence of electrical resistively and magnetic susceptibility in isothermal and non-isothermal conditions within the temperature range of room temperature to 700?C was determined for the powder samples pressed under pressure of 800 MPa. The X-ray structural examinations results correlate with those of the DSC analysis and the electrical resistively measuring.
The influence of plastic deformation and chemical environment on the resistively of al-alloy overhead lines
Authors: Nowak-Woźny D. , Mielcarek W. , Prociów K. , Woźny L. , Gajewski J.B.
Published: October 2011

The electrical resistively and intensity of X-ray diffraction reflexes were determined for overhead line wires deformed plastically and immersed at different solutions. Immersing (chemical ageing) was performed by plastic deformation along the wire axis. During chemical ageing the samples were exposed to the action of the Cl-, SO4 2-, and SO3 2- ions. Resistively was measured at room temperature and at liquid nitrogen temperature. After the X-ray and resistively measurement data were compared, it was found that three processes could take place: the flow of ions through the boundary between a sample and environment; the mechanical relaxation of vacancies near a line of dislocations, and the ordering of microstructure. These effects can lead to the anisotropy of resistively.
Temperature and yield stress characterization of electric contacts by 3D numerical simulation
Authors: Prijic Aneta , Pesic Biljana , Prijic Zoran , Pantic Dragan , Pavlovic Zoran
Published: October 2011

Electric contacts of riveted type are analyzed by 3D simulation of their mechanical, electrical and thermal characteristics. Special emphasis was put on dependencies of contacts? temperatures on chosen contact material and applied load conditions. Mechanical characteristics of contacts are considered through yield stress distributions and their maximum value dependences on contact material, geometry and dimensions. All simulations are performed for contacts within switching device, i.e. together with suitable supporting structure. Results are discussed on the basis of appropriate contact material selection and determination of reliable operating time for different geometry, dimensions and imposed loading conditions of contacts.
The point ground electrode in vicinity of the semi-spherical inhomogenity
Authors: Cvetkovic Nenad , Rancic Predrag
Published: October 2011

Characterization of the point ground electrode placed in the surroundings or inside of the semi-spherical earth inhomogenity and fed by low frequency (LF) current using isolated earthling conductor, is presented in this paper. The ground impedance (resistance and reactance) and potential distribution on the ground surface are determined. Image theory for two-layer semi conducting media, as well as for the one point electrode placed nearby or inside of the spherical body is used during the analysis.
Response analysis on nonuniform transmission line
Authors: Cvetkovic Zlata , Aleksic Slavoljub , Nikolic Bojana
Published: October 2011

Transients on a loss less exponential transmission line with a pure resistance load are presented in this paper. The approach is based on the two-port presentation of the transmission line. Using Picard-Carson's method the transmission line equations are solved. The relationship between source voltage and the load voltage in s-domain is derived. All the results are plotted using program package Mathematica 3.0.
Position control of linear induction motor using an adaptive fuzzy integral: Back stepping controller
Authors: Bousserhane I.K. , Hazzab A. , Rahli M. , Mazari B. , Kamli M.
Published: October 2011

In this paper the position control of a linear induction motor using adaptive fuzzy back stepping design with integral action is proposed. First, the indirect field oriented control for LIM is derived. Then, an integral back stepping design for indirect field oriented control of LIM is proposed to compensate the uncertainties which occur in the control. Finally, the fuzzy integral-back stepping controller is investigated, where a simple fuzzy inference mechanism is used to achieve a position tracking objective under the mechanical parameters uncertainties. The effectiveness of the proposed control scheme is verified by numerical simulation. The numerical validation results of the proposed scheme have presented good performances compared to the conventional integral back stepping control.
Reduction the effects of opamp finite gain and offset voltage in LDI termination with a minus one half delay of SC ladder filters
Authors: Radev Nikolay , Ivanov Kantcho
Published: October 2011

In this paper a combined approach for reducing the effects of op amp imperfections (finite gain A and offset voltage VOS) in first-order SC cell, realizing LDI (loss less discrete integrator) termination with a minus one half delay is presented. First, the conventional integrator is replaced with gain- and offset-compensated (GOC) integrator. Next, the gain errors m(?) and the phase errors ?(?) are further reduced by using the precise op amp gain approach in the GOC structure. The variation of the dc gain A from its nominal value A0 is taken into account.
Dynamic performances of self-excited induction generator feeding different static loads
Authors: Nesba Ali , Ibtiouen Rachid , Touhami Omar
Published: October 2011

The paper examines the dynamic performances of a three-phase self excited induction generator (SEIG) during sudden connection of static loads. A dynamic flux model of the SEIG in the ?-? axis stationary reference frame is presented. The main flux saturation effect in the SEIG is accounted for by using an accurate technique. The cases of purely resistive, inductive and capacitive load are amply discussed. Models for all of these three-phase load in the ?-? axis stationary reference frame are also given. The analysis presented is validated experimentally.
Ant colony search algorithm for optimal reactive power optimization
Authors: Lenin K. , Mohan M.R.
Published: October 2011

The paper presents an (ACSA) Ant colony search Algorithm for Optimal Reactive Power Optimization and voltage control of power systems. ACSA is a new co-operative agents? approach, which is inspired by the observation of the behavior of real ant colonies on the topic of ant trial formation and foraging methods. Hence, in the ACSA a set of co-operative agents called "Ants" co-operates to find good solution for Reactive Power Optimization problem. The ACSA is applied for optimal reactive power optimization is evaluated on standard IEEE, 30, 57, 191 (practical) test bus system. The proposed approach is tested and compared to genetic algorithm (GA), Adaptive Genetic Algorithm (AGA).
150th birth anniversary of Nikola Tesla
Authors: Stojic Milic
Published: October 2011

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Tesla’s polyphase system and induction motor
Authors: Miljanic Petar
Published: October 2011

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Interpretation of a discovery
Authors: Vuckovic Vladan
Published: October 2011

The paper presents the development of the theory of asynchronous motors since Tesla?s discovery until the present day. The theory of steady state, as we know it today, was completed already during the first dozen of years. That was followed by a period of stagnation during a number of decades, when the theory of asynchronous motors was developed only in the framework of the general theory of electric machines, which was stimulated by the problems of the development of synchronous generators and big electric networks. It is only in our time that this simple motor, which was used for a long time just to perform crude tasks, became again the inspiration for the researchers and engineers who enabled it, with the help of power electronics and semi-conductor technology, to be used in the finest drives.
The contribution of Nikola Tesla to plasma physics and current status of plasmas that he studied
Authors: Petrovic Zoran
Published: October 2011

One of the main Interests in science of Nikola Tesla were gas discharges plasmas, their application in lighting and in production of ozone as well as their role in conduction of electricity through the atmosphere. In particular Tesla is well known as the first person to produce rf plasmas. Such plasmas in the present day constitute the main technology required to produce integrated circuits (IC) and have been essential in the revolution that resulted from IC technologies. In addition Tesla participated in studies of arcs especially arcs used as a source of light, corona discharges required to induce plasma chemical reactions and produce ozone and was involved in various aspects of gas breakdown and gaseous dielectrics. His ideas, level of his understanding and current status of these fields are discussed in this review.
Fuzzy rule: Based model reference adaptive control for PMSM drives
Authors: Kadjoudj Mohamed , Golea Noureddine , Benbouzid Hachemi
Published: October 2011

The objective of the model reference adaptive fuzzy control (MRAFC) is to change the rules definition in the direct fuzzy logic controller (FLC) and rule base table according to the comparison between the reference model output signal and system output. The MRAFC is composed by the fuzzy inverse model and a knowledge base modifier. Because of its improved algorithm, the MRAFC has fast learning features and good tracking characteristics even under severe variations of system parameters. The learning mechanism observes the plant outputs and adjusts the rules in a direct fuzzy controller, so that the overall system behaves like a reference model, which characterizes the desired behavior. In the proposed scheme, the error and error change measured between the motor speed and output of the reference model are applied to the MRAFC. The latter will force the system to behave like the signal reference by modifying the knowledge base of the FLC or by adding an adaptation signal to the fuzzy controller output. In this paper, the MRAFC is applied to a permanent magnet synchronous motor drive (PMSM). High performances and robustness have been achieved by using the MRAFC. This will be illustrated by simulation results and comparisons with other controllers such as PI classical and adaptive fuzzy controller based on gradient method controllers.
Research on unequal error protection with punctured turbo codes in jpeg image transmission system
Authors: Lakhdar Moulay , Méliani R. , Kandouci M.
Published: October 2011

An investigation of Unequal Error Protection (UEP) methods applied to JPEG image transmission using turbo codes is presented. The JPEG image is partitioned into two groups, i.e., DC components and AC components according to their respective sensitivity to channel noise. The highly sensitive DC components are better protected with a lower coding rate, while the less sensitive AC components use a higher coding rate. While we use the s-random interleaver and s-random odd-even interleaver combined with odd-even puncturing, we can fix easily the local rate of turbo-code. We propose to modify the design of s-random interleaver to fix the number of parity bits. A new UEP scheme for the Soft Output Viterbi Algorithm (SOVA) is also proposed to improve the performances in terms of Bit Error Rate (BER) and Peak Signal to Noise Ratio (PSNR). Simulation results are given to demonstrate how the UEP schemes outperforms the equal error protection (EEP) scheme in terms of BER and PSNR.
Fuzzy control of induction motor with reduced rule base
Authors: Chatterjee Pradeep , Karan B.M. , Sinha P.K.
Published: October 2011

Several methods have been proposed and published for control of induction motors. The objective of this work is to develop a fuzzy controller with reduced rule base. Using concepts of direct torque control, a fuzzy controller has been designed with a cascaded final state selector, which reduced rule base and gave birth to a new control technique of induction motor. Details and performance of the fuzzy controller has been discussed in the paper.
An optical technique based mark tracking for electrical field induced mechanical strain measurement in thin polymer films
Authors: Zegnini B. , Boudou L. , Vega Martinez
Published: October 2011

An optical non contact measurement technique based on the tracking of successive positions of computerized markers has been developed which enables one to characterize the electric field induced strain response of the plane gold-metalized surfaces in thin organic insulating films. The present study was made on two microstructures of films: a virgin amorphous material and some semi-crystalline samples 70?m thick were obtained by annealing the amorphous one at annealing temperatures of 170?C at 5, 60 and 120 minutes using Differential Scanning Calorimetry (DSC). The test results demonstrate that the newly developed method is capable of detecting displacement of selected markers when the sample is subjected to the application of a dc high voltage. The field-induced mechanical strain measurements have been performed as a function of time and then analyzed with respect to the applied electric field. The observed strain levels varied from ~ 10-3 to 10-2. Moreover the influence of crystallinity on the electric field induced strain mechanical response is discussed.
Future 400 kV Algerian network and radio electric disturbances in dry weather and under rain
Authors: Brahami M. , Tilmatine A. , Kanssab A. , Bendaoud A.
Published: October 2011

The development of the electrical power networks to very high voltage (V.H.V) reveals problems involved in the high electric fields; it is essential to consider it in the design of installations in order to avoid or to mitigate some problematic or dangerous effects. Among the most important harmful effects, we can note the "radio interference disturbances". The principal aim of this paper is the use of a simulation programme using an analytical method based on the theory of propagation modes, made by one of the authors, for determination and calculation of the exact profile of disturbance field of actual high voltage lines (220 kV) and in project (400 kV) in dry weather and under rain. Specific software called "effect corona" was developed for this purpose.