bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of the Geometric of (Al) Hollow Cathode on Paschen Curves in Nitrogen
Authors: Khadayeir Abdul hussain A. , Taher Wessam M. 
Published: July 2019

Abstract
In this paper, an experimental study of DC hollow cathode glow discharge plasma at different nitrogen pressures ranged from (0.065 to 0.75Torr) has been proposed. Investigated was carried out under the influence of the hollow cathode geometry such as diameter and depth of hollow cathode on the breakdown voltage of the nitrogen gas, the discharge system consists of two electrodes, the cathode forms various geometrical shapes and anode as a disc- shaped with diameter (8.8cm). The electrodes are enclosed in a large cylindrical glass chamber of pyrex filled with nitrogen gas. Three important physical parameters affecting the condition of the discharge are the gas pressure, constant inter-electrode distance and the cathode geometry. We used the hollow cathode with geometric shapes such as Cylindrical, conical, oppressive and variable dimensions. The cylindrical and conical shapes have inner diameters (3 & 6) cm and repressive shapes have inner diameter (1 & 2) cm. The breakdown voltage Vb is shown to depend on the product (p.d), for lower values of pressure, p or gap, d. This work represents the investigation of the dependence of the breakdown voltage on the gas pressure and on the distance between electrodes and the cathode geometry. The minimum value of breakdown voltage increases with increases gap d or increase the diameter of the hollow cathode with the length of the cavity is fixed.
An assessment of soil salinity and vegetation cover changes for a part of An-Najaf governorate using remote sensing data
Authors: Al-Khakani Ebtihal T , Yousif Sa’ad R 
Published: July 2019

Abstract
This paper deals with assessing and detecting the changes of soil salinity and vegetation cover for a part of An-Najaf Governorate and verification regarding the impression of soil salinity on the change of vegetative regions, over the period from 2001 to 2015. The results demonstrated a clear reduction in vegetative cover with salinity rates increased. The normalized difference vegetation index (NDVI) and Soil Salinity Index (SI) were applied for each date using the multispectral images derived from Landsat ETM+ and OLI data. Then image differencing technique was utilized to detect the change/no-change for vegetation and salinity for the two study periods. The results revealed that soil salinity increased from 6.36 in 2001-2009 period to 10.59% in 2009-2015, whereas the vegetation cover deteriorated to 9.95 % for the same period. Finally, the strong inverse correlation which found in this paper between NDVI and SI emphasizes that vegetation cover on long term is heavily and directly affected by changes of soil salinity.
Comparison of the methods of solid state reaction and sol-gel in the preparation of HgBa2Ca2Cu2.8Zn0.2O8+δ superconducting compound
Authors: Haider Haider MJ. , Jasim Kareem A. 
Published: July 2019

Abstract
This paper investigated the influence of the preparation method change on the superconductivity properties and crystal structure of HgBi2Ca2Cu2.8Zn0.2O8+δ. The crystal structure was examined by XRD for all prepared samples, it was found that consist of a major 1223 high -Tc phase. However, the electrical resistivity as a function of temperature was used to calculate critical temperature Tc, Tc (offset) = 121K,126K and Tc(onset)=124K, 131K for (SSR),(SG) respectively. While the samples dielectric properties which includes (Dielectric constant (real & imaginary), Loss tangent and Alternating electrical conductivity),were studies as a function of the frequency and range (50 Hz-1MHz) at room temperature.
A modified E-shaped microstrip patch antenna for dual band in x- and ku-bands applications
Authors: Godaymi Al-Tumah Wa’il A. , Shaaban Raed M. , Ahmed Zeki A. 
Published: July 2019

Abstract
In this paper, different shapes of an E-patch microstrip antenna designed and operating at x- and ku-bands by using High Frequency Structure Simulator (HFSS) software version 13. The finite element method used to solve electromagnetic values. The dielectric substrate material is Arlon AD320A (tm) with dielectric constant (εr = 3.2) and thickness h=1.79 mm used in this design. The new designs including modifying and slotting E-patch increased the gain of proposed antennas and provided a dual band frequency in x- and ku- bands. The return loss, voltage standing wave ratio (VSWR) and radiation patterns are evaluated.
Theoretical study of electronic properties for pristine and alloyed double metal rings
Authors: Merdas Samar M. , Al-Badry Lafy F. , Hanoon Falah H. 
Published: July 2019

Abstract
The present work is a theoretical study of the electronic properties of pristine and alloyed double metal rings threaded by magnetic flux in the presence of transverse flux. The system that takes into account in the study is consisting of two rings connected in parallel, with the same type of atomic sites for pristine double metal ring, and with two different types of atomic sites for an alloyed double metal ring. The tight-binding method was used to calculate the energy spectrum and persistent current in presence of transverse flux. Our results show that the transverse flux causes bending of the persistent current and increase in current amplitude at the pristine double metal ring, while it leads to asymmetry at alloyed double metal ring. The energy gap is not affected by the transverse flux.
Ternary Cu2SnS3 Thin Films Deposited by Fully Controlled System of Spray Pyrolysis
Authors: Hadi Zaid L. , Essa Mohammed Sh. , Chiad Bahaa T. 
Published: July 2019

Abstract
A fully computerized system of spray pyrolysis was employed for fabricating copper tin sulphite ternary thin film onto glass substrates. During deposition process, the glass substrate was maintained at 310 ± 10 °C. After dissolving the raw chemicals, a mixture of their aqueous solutions was used for spraying process. The optimum solution mixture at the volumetric ratio [S/(Cu+Sn)=1] at 1.5 of pH. XRD investigation was approved a monoclinic phase of CTS. A number of different platform speed was tested in the deposition process. XRD diffraction peaks were described at 2θ = 28.39°, 33.02°, 47.34°, and 56.39° corresponding to the

(

2
¯

1
¯

1
)

(

2
¯

0

6
)
,

(

2
¯

0

10
)
,

and

(

3
¯

2
¯

10
)

, respectively. These are crystal planes of monoclinic copper tin sulphide. The FTIR study certified a number of the chemical bond of Cu-, Sn- and S-. The grain size was observed in the range of nano using Scherrer formula. Studying surface morphology of CTS films reveals a uniform coating on the substrates which approved by SEM investigations.
Study optical properties of R6G dye doped in polymer PVA
Authors: Tahir K J , Obeed H H , Shiltagh N M 
Published: July 2019

Abstract
The linear and nonlinear optical properties for laser dye R6G is investigated in solvent methanol at different concentrations (5x10-4, 1x10-4, 1x10-5, 5x10-6 and 1x10-6 Ml) at thickness (2µm). The nonlinear optical properties as refractive index (n2
) and the nonlinear absorption coefficient (β) were studied by using Z-Scan technique in two parts; one part by putting aperture in front of the detector (close aperture) to find the nonlinear refractive index, however in second part is by removing the aperture (open aperture) to find nonlinear absorption coefficient, these by using two wavelengths 532, 1064 nm. The results show the effects of self – focusing in 532 nm and other concentrations in 1064 nm and the change of the saturation absorption effect in open aperture in both wavelengths. The higher nonlinear refractive index is found (n2
=29.93cm2/mw) in the concentration (1*10-4 Ml), while the higher nonlinear absorption coefficient is (β=8.88cm/mw) in the concentration (5*10-4Ml) at the wavelength 532 nm.
Construction of ZnO-Nanoflowers Photoanode for Photoelectrochemical Cell
Authors: Mebdir Holi Araa , Kadim Ayal Asmaa , Ali Baqer Anwar 
Published: July 2019

Abstract
ZnO-nanoflowers on a transparent conductive tin-doped In2O3 (ITO) glass substrate have been successfully prepared via a simple and efficient growth approach that is combining of dip coating and hydrothermal processes. One thin layer of ZnO nanoparticles is prepared by dip coating method followed by hydrothermally grown of ZnO nanoflowers at low temperature. The morphology and structure of ZnO-nanoflowers were inspected by field-emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD), respectively. The optical absorption and photoluminescence spectra of ZnO-nanoflowers are also investigated. The ZnO-nanoflowers photoanode shows dramatically contributed to the separation of electron-hole pairs and enhanced the photoresponse. The photocurrent density is 0.44 mA/cm2 indicated that the PEC cells based on ZnO-nanoflowers photoanode have promising application potential in overall solar energy.
Electronic Properties in Single-Orbital Crystalline System Using Tight-Binding Approximation
Authors: Al-Galiby Qusiy H. , Shabeeb Dakhil Sarah 
Published: July 2019

Abstract
Using quantum theory (QT) combined with Tight-binding Approximation (TBA), we studied the electronic properties for single-orbital one dimensional, two-dimensional and diatomic crystalline chain to get simply qualitative understanding of electronic structure calculation in the periodic systems. Density of states (DOS) is one of the electrical properties that we try to understand within the band structures that lead to be able to know the mechanism of transport in the materials. The band structure and density of state (DOS) for both cases were calculated by using FORTRAN code. The calculation of DOS for ordered and disordered systems were performed via a numerical decimation method.
Effect of Black Cumin (Nigella sativa) Extracts in Inhibiting of the Mutagenic Activity of Mitomycin C in Albino Mice
Authors: Raheem Al-Aamiri Aseel 
Published: July 2019

Abstract
The aim of this study is to investigate the ability of black cumin (Nigella sativa) aqueous extracts in reducing the genotoxic effects induced by mitomycin C (MMC) in male mice Mus musculus (balb/c strain). Nigella sativa (N. sativa) has been widely used as a medicinal plant that treats different diseases. To determine the genotoxic effects of mitomycin C, the mitotic index of somatic and germ cells and chromosomal aberrations (chromatid breaks, chromosome breaks, and ring chromosomes) were tested. Twenty-five animals were divided into three main groups: group one was used as a negative control treated with buffer saline, group two was used as a positive control treated orally with mitomycin C (2 mg/kg b. w.) for two days; group three, which was divided into three sub groups, was treated orally with three different doses of N. sativa extracts (50, 100, 150 mg/kg b. w.) for one week, and then treated with mitomycin C for two days. The results of this study showed a protective role of N. sativa effecting a significant increase (P<0.05) of the frequency of mitotic index of both somatic and germ cells. Additionally, N. sativa may improve therapeutic efficiency of mitomycin C by inhibiting the chromosomal aberrations.
Assessment of some heavy metals contamination in sediments of Tigris River in Kut City, Wasit Governorate, Iraq
Authors: Obaid Maiws Al-Mayyahi Sattar , Ali Awad Al-Zamili Hussein 
Published: July 2019

Abstract
The grade of contamination in the Tigris River sediments in the Kut City by heavy metals Co, Cu, Cr, Mn, Ni, Pb, Zn and Cd has been evaluated by using some pollution indices like Enrichment factor (EF), geo-accumulation (I-geo), contamination factor (CF) and pollution load (PLI). The (EF, enrichment factor) is one of the most factors applied as a way to describe the degree of anthropogenic pollution to find enrichment ratios, where on the geo-accumulation has been mostly applied as a measurement of contamination in freshwater sediment. Whereas, the index of pollution load (PLI), appear the sum of times by which the heavy metals concentrations in the sediment exceed the level, concentration and accord a guide to the total level of heavy metals is toxicity in a special sample. By using these numerical sediments indices we found that the Sediments of Tigris River in the Kut city are polluted by the metals of Lead and Cadmium, and moderately polluted by the metals of Nickel, Zinc and Copper, while the sediments of Tigris River are not polluted by the metals of Manganese, Cobalt and Chromium.
Mechanical and Thermal Properties of Natural Rubber/Poly Lactic Acid /dioctadecyldimethylammonium bromide Modified Clay Nanocomposites
Authors: Hoidy W H , Al-Mulla E A J , Essa Sh M 
Published: July 2019

AbstractThis paper tackles a me1t blend of po1y(lactic acid)/ natura1 rubber with dioctadecyldimethylammonium bromide(DODAB) modified clay. The study investigated mechanical, therma1 and morpho1ogical properties of poly(lactic acid)/ natural rubber and nanocomposites. The paper also examined Montmori1lonite clay with alky1 ammonium ion of (DODAB). the studied parameters, PLA/ NR nanocomposites revealed 1arger enhancements in mechanical properties in comparison to PLA/ NR blend because of high polymer blend matrix shear forces exerted on clay aggregated during mixing po1ymer-clay. The original MMT with Na+ action leads to weak improvements in mechanica1 properties in comparison to organoclays. It is noted that the strength of tensile, modulus, and the nanocomposite samples can be improved with 4% of clay loading. The optimum samp1e morphology and chemical structure were tested by X-ray diffraction and FT-IR spectroscopy respectively. This paper denotes that poly(lactic acid)/ natural rubber-toughened nanocomposites with a higher modulus and in this way, thermal stability could be made.
Cloud point extraction of Cefixime drug by direct (UV- Vis) spectrophotometer and indirect(Flame Atomic Absorption) technique
Authors: Dhahir S A , Mohammed N J 
Published: July 2019

Abstract
A new method for the determination of the Cefixime drug in some Pharmaceuticals using ultra violet-visible (UV- Vis) and indirect Flame Atomic Absorption Spectrophotometry (FAAS) by Cloud point Extraction by using Triton X-114 as surfactant, the method based to form chelating complex CEF – Pd (II) at 456nm, variables parameters were studied such as the concentration of metal ion, effect of pH, Triton X-114 amount, equilibration temperature and incubation time. The best pH for the formation of chelating complex was (9). The best temperature on cloud-point extraction was 55 0C at 20 min. then complex extracted with ethanol. The mole-ratio method has been used to determine the structure of chelate CEF – Pd (II) and found to be 1:1 L:M (Ligand : Metal). Beer’s Law was obeyed in the range 2.5-30 and 2.5-32.5μg/mL for UVVis and FAAS respectively. Limit of Detection and Limit of Quantitation LOD and LOQ values for these methods were (0.456592, 0.33374) μg/mL (1.521976, 1.112471) μg/mL respectively.the method was validated and successfully applied to drug formulations like Cefix capsules marketed in Iraq. The results of analysis have been validated statistically and by recovery studies and were found satisfactory
On Smarandache Filter of a Smarandache BH-Algebra
Authors: Hadi Abbass Husein , Mohsin Luhaib Qasim 
Published: July 2019

Abstract
In this paper, The notion of a Smarandache filter of a Smarandache BH-Algebra is introduced, some theorems and examples are investigated and discussed to explain properties of this notion. A necessary and sufficient condition is derived for every Smarandache filter of a Smarandache BH-Algebra to become a filter. Finally, the relationships between this notion and Smarandache ideal are established
A Quantum Calculus Analogue of Dynamic Leontief Production Model with Linear Objective Function
Authors: Al-Salih Rasheed , Habeeb Ali , Laith Watheq 
Published: July 2019

Abstract
In this paper, we present a new formulation for the Leontief production model using quantum calculus analogue. This formulation unifies discrete and continuous Leontief production models. Also, the classical Leontief production model is obtained by choosing q = 1. In addition, briefly give an introduction to quantum calculus. We present the formulation for continuous Leontief production models as well as quantum calculus models. Moreover, we establish the weak duality theorem and the strong duality theorem for quantum calculus analogue. Furthermore, using the objective functions for the primal and the dual quantum calculus models, we can easily obtain upper and lower bounds for the value of production at any production plan. Finally, examples are provided in order to illustrate the given results.
Existence of Nonoscillatory Solutions of First Order Non-Linear Neutral Differential Equations
Authors: Mohamad H A , Sharba B A J 
Published: July 2019

Abstract
In this paper, some sufficient conditions have been obtained for the existence of positive solutions of the first order nonlinear neutral differential equations bounded by a ratio of bounded functions. For this purpose we used Krasnoselskii’s fixed point theorem and Lebesgue’s dominated convergence theorem to establish new sufficient conditions for the existence of nonoscillatory positive solutions. An example is included to illustrate the main result.
Numerical study of the flow structure in the supersonic inlet-isolator with mechanical throttle
Authors: Seleznev R K 
Published: July 2019

Abstract
In the paper three-dimensional model for hypersonic flow with turbulence model described. Comparing the result of calculation with wall pressure experimental data, obtained in the inlet-isolator model mounted to the floor of a Mach 5 wind tunnel at the University of Texas, presented in this article. A study is being conducted on the phenomenon of unstart of air inlet-isolator. The results of the distribution of pressure, the Mach number and the temperature inside the inlet-isolator at successive points in time presented.
Numerical simulation of a hypersonic flow over HB-2 model using UST3D programming code
Authors: Kryuchkova A S 
Published: July 2019

Abstract
Numerical modeling of a flow over HB-2 model using UST3D programming code was carried out. Aerodynamic coefficients dependencies from Mach number and angle of attack were compared to various experimental tests results. Good accordance of the numerical method predictions with empirical data was demonstrated. The numerical simulation has provided an extra UST3D code validation in application to aerodynamic calculations of hypersonic flows.
Visualization of the shock wave diffraction on the wedge in a rectangular channel
Authors: Znamenskaya I A , Ivanov I E , Naumov D S , Kulkin M K 
Published: July 2019

Abstract
The evolution of a shock wave interaction with a boundary layer on the surface of a shock tube channel after its reflection from a thin wedge is investigated. Visualization of the incident plane shock wave, the bow detached shock wave and flow behind the wedge in 48x24 mm channel was performed using the shadow method based on high-speed recording. The zone of boundary layer separation that occurs when the plane attached bow shock intersects with the channel wall is visualized on the basis of the pulse discharge glow recording. The flow evolution at incident shock wave Mach number of 2.3÷3.8 for the time interval up to 5 ms after the diffraction is investigated. The obtained data is compared with the corresponding CFD results: a numerical simulation based on the Euler equations of a nonstationary two-dimensional flow was performed under experimental conditions.
Experimental study of slow electrical explosion of thin titanium wires
Authors: Skryabin A S , Pavlov A V , Kartova A M , Telekh V D , Sytchev A E , Sachkova N V , Serov M M 
Published: July 2019

Abstract
The paper presents results of experimental studies of a slow (during 50÷100 μs) electric explosion of thin titanium wires in argon and air media. In that explosion wire destruction and its fragmentation are complex processes associated with thermo-mechanical stresses and electromagnetic forces. The explosion was characterized by oscillography and photography. Schlieren photos of the explosion allowed to visualize features of the wire dispersion. It was demonstrated that the nature of wire defragmentation was determined by a specific energy input QR
. At QR
≈1.2÷1. 5 J/mg wire fragmentation occurred with the formation of micron particles (with a diameter of 50÷150 μm). At QR
≈2.5÷2.8 J/mg forming of not only micron particles but also titanium nano powders due to electric arc ignition and extreme wire evaporation with the following non-equilibrium condensation. In the mode of high specific energy inputs generation of shock waves took place. The measured wave velocities reached of 700÷750 m/s. The manufactured titanium particles had purity of 96.65÷99.01 % as for raw wires.
The Radio-Frequency Capacitive Normal Glow Discharge in Axial Magnetic Field
Authors: Surzhikov S T 
Published: July 2019

Abstract
A numerical model of a normal axisymmetric high-frequency capacitive glow discharge in an axial magnetic field is considered. The analysis of previous investigations on α- and γ-forms of high-frequency discharges was performed. Using the author’s created numerical model, a study of the electrodynamic structure of a normal high-frequency axially symmetric glow discharge was performed with the following parameters: distance between electrodes of H = 2 cm, pressure of p = 5 Torr, amplitude voltage drop on the inter-electrode gap of E0 = 460 and 478 V, coefficient of the secondary ion-electron coefficient emissions of γ = 0.33. The two-dimensional electrodynamic structure of the γ-form of the high-frequency glow discharge was studied without and with an axial magnetic field induction of B

x
= 0.1 T. A qualitative explanation of the reasons for the radial expansion of the current channel of a high-frequency discharge in a normal mode is given.
Positioning of space objects by laser-induced jets
Authors: Loktionov E Y , Sitnikov D S 
Published: July 2019

Abstract
Laser-induced thrust provides a number of significant advantages over the currently used methods: virtually any material can be used as a working medium; radiation source and its power unit can be located outside the spacecraft; it is possible to provide a minimum impulse bit of 1 nN s or less; momentum imparted at single impact can be controlled within 2 orders of magnitude dynamic range. We have considered recoil momentum generation at femtosecond to continuous laser impact range on different materials normalized by laser output performance to evaluate momentum coupling to on-board energy system. It is shown that better momentum coupling at short wavelength is not worth of associated energy losses, but laser pulse shortening to picosecond range is. Data reported here on laser thrust generation efficiency and methods of laser impact layout are of interest not for small spacecraft application range broadening only, but also for the prevention of emergency situations development (launch to unplanned orbit, uncontrolled rotation, etc.), space debris removal, and anti-asteroid protection of the Earth – possible impact layouts for such missions are considered.