bluuebunny/crossref_metadata_2025 huggingface dataset:
Laser-produced plasmas as drivers of laboratory collisionless quasi-parallel shocks
Authors: Heuer P. V. , Weidl M. S. , Dorst R. S. , Schaeffer D. B. , Tripathi S. K. P. , Vincena S. , Constantin C. G. , Niemann C. , Winske D.
Published: April 2020

The creation of a repeatable collisionless quasi-parallel shock in the laboratory would provide a valuable platform for experimental studies of space and astrophysical shocks. However, conducting such an experiment presents substantial challenges. Scaling the results of hybrid simulations of quasi-parallel shock formation to the laboratory highlights the experimentally demanding combination of dense, fast, and magnetized background and driver plasmas required. One possible driver for such experiments is high-energy laser-produced plasmas (LPPs). Preliminary experiments at the University of California, Los Angeles, have explored LPPs as drivers of quasi-parallel shocks by combining the Phoenix Laser Laboratory [Niemann et al., J. Instrum. 7, P03010 (2012)] with a large plasma device [Gekelman et al., Rev. Sci. Instrum. 87, 025105 (2016)]. Beam instabilities and waves characteristic of the early stages of shock formation are observed, but spatial dispersion of the laser-produced plasma prematurely terminates the process. This result is illustrated by experimental measurements and Monte Carlo calculations of LPP density dispersion. The experimentally validated Monte Carlo model is then applied to evaluate several possible approaches to mitigating LPP dispersion in future experiments.
A study of the propagation of a solitary wave along the magnetic field in a cold collision-free plasma
Authors: Abbas Gohar , Allen J. E. , Coppins M. , Simons L. , James L.
Published: April 2020

A detailed study has been carried out on the propagation of a solitary wave along the magnetic field in a cold collision-free plasma. With the quasi-neutral approximation and the conservation of momentum flux and energy flux in the wave-frame, the exact analytical solutions of the stationary solitary pulse in terms of particle densities, parallel and transverse velocities, and transverse magnetic fields are presented without performing numerical integration. Graphical representations of the solutions and in particular the 3D structures of the transverse magnetic and velocity field lines are presented.
Measuring the surface bonding energy: A comparison between the classical double-cantilever beam experiment and its nanoscale analog
Authors: Pantzas K. , Fournel F. , Talneau A. , Patriarche G. , Le Bourhis E.
Published: April 2020

Two experimental implementations of the double-cantilever beam experiment, developed to measure the bonding energy in wafer-bonded semiconductors, are compared for the first time. The comparison is carried out in two material combinations relevant to microelectronics and silicon photonics: Si on an insulator and InP on Si. Although the two implementations differ in the scale of the measured sample area, the measurement conditions, and the step in the fabrication process at which they are applied, they are shown to yield the same values for bonding energy within experimental errors. Both techniques also show the same trend in the evolution of bonding energy when the samples are subjected to annealing.
Plane wave basis set correction methods for RPA correlation energies
Authors: Riemelmoser Stefan , Kaltak Merzuk , Kresse Georg
Published: April 2020

Electronic correlation energies from the random-phase approximation converge slowly with respect to the plane wave basis set size. We study the conditions under which a short-range local density functional can be used to account for the basis set incompleteness error. Furthermore, we propose a one-shot extrapolation scheme based on the Lindhard response function of the homogeneous electron gas. The different basis set correction methods are used to calculate equilibrium lattice constants for prototypical solids of different bonding types.
Eye movements in vocabulary research
Authors: Pellicer-Sánchez Ana , Siyanova-Chanturia Anna
Published: April 2020

The field of vocabulary research is witnessing a growing interest in the use of eye-tracking to investigate topics that have traditionally been examined using offline measures, providing new insights into the processing and learning of vocabulary. During an eye-tracking experiment, participants’ eye movements are recorded while they attend to written or auditory input, resulting in a rich record of online processing behaviour. Because of its many benefits, eye-tracking is becoming a major research technique in vocabulary research. However, before this emerging trend of eye-tracking based vocabulary research continues to proliferate, it is important to step back and reflect on what current studies have shown about the processing and learning of vocabulary, and the ways in which we can use the technique in future research. To this aim, the present chapter provides a comprehensive overview of current eye-tracking research findings, both in terms of the processing and learning of single words and formulaic sequences. Current research gaps and potential avenues for future research are also discussed.
Re-examining the effects of word writing on vocabulary learning
Authors: Webb Stuart , Piasecki Anna
Published: April 2020

This study investigated the effects of word writing on vocabulary learning by comparing three conditions in which there was (a) limited time to write words, (b) unlimited time to write words, and (c) a non-writing word-picture pairs comparison. Non-native speakers studying English as a second language encountered 8 word-picture pairs in each condition and were administered a test measuring form recall and another measuring receptive knowledge of written form. The results indicated that there was little difference between scores on both tests when time on task was the same. However, when the participants had as much time as they needed to write and learn words, they had higher scores on both dependent measures than when learning in the other two conditions. The findings suggest that an ecologically valid approach to word writing may facilitate vocabulary learning.
The effect of out-of-class exposure to English language media on learners’ vocabulary knowledge
Authors: Peters Elke
Published: April 2020

The aim of this study is to investigate (1) how often Flemish English-as-a-foreign language learners are exposed to English language media outside of the classroom, (2) whether current out-of-class exposure to English language media is related to learners’ vocabulary knowledge, and (3) whether length of instruction (three or six years), gender, and out-of-class exposure to English language media affect Flemish learners’ vocabulary. Data were collected with 79 English-as-a-foreign language learners. They were administered a frequency-based vocabulary test and a questionnaire. The findings of this study show that Flemish English-as-a-foreign language learners are frequently exposed to English language media. The results also indicate a positive relationship between learners’ vocabulary knowledge and exposure to non-subtitled TV programs and movies, the Internet, and written print (books, magazines). Finally, both length of instruction and current out-of-class exposure to English language media had an effect on learners’ vocabulary knowledge, but out-of-class exposure had a larger effect than length of instruction.
Uvulars and uvularization in Tangut phonology
Authors: Gong Xun
Published: April 2020

Tangut, a mediaeval Qiangic language (Sino-Tibetan family) distinguishes three grades (děng
等). The traditional Sofronov-Gong reconstruction of this
distinction postulates different degrees of medial yod: Grade I {-Ø-}, Grade II {-i-}, Grade III
{-j-}. The yods, however, are not supported by the transcriptional evidence. Based on cognates between Tangut
and Rgyalrongic languages, this study proposes the uvularization hypothesis: Tangut syllables have contrastive
uvularization. Grade I/II syllables are uvularized, while Grade III syllables are plain. For phonological velars, uvularized
syllables trigger a uvular allophone, while plain syllables trigger a velar allophone. Tangut uvularization is an instance of a
common typological feature in Qiangic languages, that of Guttural Secondary Vocalic Articulations (GSVA),
variously termed uvularization, velarization, tenseness, or Retracted Tongue Root (RTR). Recognizing Tangut
grades as a case of Qiangic GSVA has far-ranging potential consequences for Sino-Tibetan comparative linguistics.
A revisit to the [Num-Cl-Modifier-de-N]/ [Modifier-de-Num-Cl‑N] variation in Mandarin Chinese
Authors: Jin Jing
Published: April 2020

This paper investigates the licensing condition of the [Num(eral)-Cl(assifier)-Mod(ifier)-de-N(oun)] / [Mod-de-Num-Cl‑N] variation in Mandarin Chinese. It is observed that this variation represents a complex interface phenomenon in the nominal domain, which is subject to the semantic condition concerning the i(ndividual)-level/​s(tage)-level nature of the modifier contained on the one hand, and the discourse-related condition concerningcontrastive topic(ct) on the other. Based on this, at the syntax-semantics interface level, this paper proposes a division of the syntactic domain of adnominal modification to account for the discrepancy between i‑level and s‑level modifiers in terms of their capability in forming [Mod-de-Num-Cl‑N] in the neutral context. In the meanwhile, at the syntax-discourse interface level, in light of the interface-induced analysis pursued byNeeleman & Van de Koot (2008)andHorvath (2010), it is claimed that the word order of [Mod-de-Num-Cl‑N] could be adopted as a linguistic device to encodectwithin the nominal domain in Mandarin Chinese, in which case the ordering of [Mod-de-Num-Cl‑N] is licensed for the purpose of establishing a transparent mapping between syntactic configuration and information structure.
Local active isolation of the AEI-SAS for the AEI 10 m prototype facility
Authors: Kirchhoff R , Mow-Lowry C M , Bergmann G , Hanke M M , Koch P , Köhlenbeck S M , Leavey S , Lehmann J , Oppermann P , Wöhler J , Wu D S , Lück H , Strain K A
Published: April 2020

High precision measurements in various applications rely on active seismic isolation to decouple the experiment from seismic motion; therefore, closed feed-back control techniques such as sensor blending and sensor correction are commonly implemented. This paper reviews the active isolation techniques of the Albert Einstein Institute seismic attenuation system (AEI-SAS). Two approaches to improve the well known techniques are presented. First, the influence of the sensor basis for the signal-to-noise ratio in the chosen coordinate system is calculated and second, a procedural optimization of blending filters to minimize the optical table velocity is performed. Active isolation techniques are adapted to the mechanical properties and the available sensors and actuators of the AEI-SAS. The performance of the final isolation is presented and limitations to the isolation are analyzed in comparison to a noise model. The optical table motion reaches approximately

8
×
1

0

−
10

m
/

H
z

at 1 Hz, reducing the ground motion by a factor of approximately 100.
Multiple-fibre interferometry setup for probe sample interaction measurements in atomic force microscopy
Authors: Klapetek Petr , Yacoot Andrew , Hortvík Václav , Duchoň Václav , Dongmo Herve , Řeřucha Šimon , Valtr Miroslav , Nečas David
Published: April 2020

Atomic force microscopy (AFM) often relies on the assumption that cantilever bending can be described by simple beam theory and that the displacement of the tip can be evaluated from the cantilever angle. Some more advanced metrological instruments use free-space or fibre interferometers for measuring the position of the cantilever apex directly, thereby simplifying the metrology traceability chain. The next logical development, covering measurements of both the cantilever apex position and its deformation due to lateral forces acting during different AFM measurement regimes, is presented in this paper. It is based on using a set of closely packed fibre interferometers that can be used to determine localised bending of the cantilever at different positions along the cantilever. This can be used for detection of cantilever deformation beyond classical beam theory, and can yield both better understanding of sources of uncertainty in individual AFM force–distance measurements and more accurate scanning in constant height mode in high-speed AFM applications.
Influence of matrix-metalloproteinase inhibitor on the interaction between cancer cells and matrigel*
Authors: Ye Teng , Ye Fangfu , Qiu Feng
Published: April 2020

Various behaviors of cancer cells are strongly influenced by their interaction with extracellular matrices (ECM). We investigate how this interaction may be influenced if the cancer cells’ ability of secreting matrix metalloproteinases (MMPs) to degrade ECM is inhibited by adding the MMP inhibitor. We use MDA-MB-231-GFP cells as model cells and use matrigel to mimic ECM. It is found that the added MMP inhibitor significantly reduces the migration speed of cancer cells covered by matrigel but has little influence on the migration persistence and shape factor of the cells and that with the MMP inhibitor added the presence of matrigel on the top has no influence on the migration speed of the cells but increases the cells’ shape factor and migration persistence.
Features of the thermal structure of reaction waves in the Ti - Mo – N2 system
Authors: Gabbasov R M , Salamatov V G
Published: April 2020

The thermal structure of filtration combustion waves in the metallic Mo – Ti system in nitrogen is studied by dynamic color pyrometry. It’s shown that the combustion of the samples is conducted in the surface mode. This mode is characterized by the propagation of a reaction wave in a narrow near-surface layer of the sample followed by the penetration of combustion from the surface to the centre. The peculiarities of combustion observed are the presence of local reaction sources in the surface reaction wave and the complex three-dimensional structure of the temperature field in the reaction wave (local reaction source – surface reaction wave - inside reaction wave). The measurements have shown that with increasing nitrogen pressure, the maximum temperature inside the sample rises by 200 K.
Mathematical model for mechanical treatment of a reactive binary mixture passivated by inert material
Authors: Lapshin O. V. , Ivanova O.V.
Published: April 2020

A macroscopic mathematical model was built to theoretically study the mechanical treatment of a reactive solid mixture passivated by an inert substance milled from the walls of a mill chamber and grinding bodies. The model includes equations for the rate of chemical transformations, change in the mass of substances involved in the mechanical treatment, dynamics of excess energy in components and a reaction product. The process is considered to be isothermal. An equation is derived to obtain the function of the interphase, which is a superposition for the grinding of components and their passivation with an inert substance. The dynamics of the chemical transformation depth, the amount of a milled inert substance, the function of the interphase and reactivity of the mixture versus the mechanical treatment time are numerically calculated. The final fraction of the reaction product in the mechanically treated powder mixture is found as a function of the parameter characterizing the level of slagging of reagents with an inert substance. Based on the constructed calculation diagrams, it is shown that depending on the parameters determining the mechanical treatment, different modes that characterize either activation or passivation of chemical interaction in the reactive powder mixture were found.
Mathematical model of gas-free combustion of a binary powder mixture with allowance Marangoni convection
Authors: Prokof’ev V.G. , Lapshin O V
Published: April 2020

A macroscopic mathematical model has been developed for the gas-free combustion of a binary reaction mixture with allowance for thermocapillary convection of a low-melting reagent. The model includes equations as follows: mass balance of reaction substances, chemical transformation, melt motion, thermal conductivity. Melt formed during the melting of one of the components is believed to move in the porous carcass of the mixture due to thermocapillary forces. The dynamics of changes in temperature, chemical conversion depth, melt fraction and porosity are numerically calculated in a gasless combustion wave. Depending on the main parameters characterizing the process, conductive, convective, and mixed modes of synthesis front propagation are revealed. Analytical relationships are derived to estimate the combustion rate for these modes. An approximate criterion that reveals the synthesis mode from the structural and physicochemical parameters of the binary mixture is found.
Quasilinear systems of Jordan block type and the mKP hierarchy
Authors: Xue Lingling , Ferapontov E V
Published: April 2020

Hydrodynamic type systems in Riemann invariants arise in a whole range of applications in fluid dynamics, Whitham averaging procedure, differential geometry and the theory of Frobenius manifolds. In this paper we discuss parabolic (Jordan block) analogues of diagonalisable systems. Our main observation is that integrable quasilinear systems of Jordan block type are parametrised by solutions of the modified Kadomtsev–Petviashvili hierarchy. Such systems appear naturally as degenerations of quasilinear systems associated with multi-dimensional hypergeometric functions, in the context of parabolic regularisation of the Riemann equation, as finite-component reductions of hydrodynamic chains, and as hydrodynamic reductions of linearly degenerate dispersionless integrable PDEs in multi-dimensions.
Effect Gamma rays effect on Wear rate and Hardness of ( Ep-SiC ) Nanocomposites for Industrial applications
Authors: Aobaid A K , Alqaisy T Y
Published: April 2020

The aim of this research is to measure the hardness and wear rate for epoxy resin as a base material, nano ceramic powder (SiC) with particle size ( 64.85nm ), were used as a reinforcement materials in composites preparation in different weight fractures (2%, 4%, 6%), hand-casting method was used in preparation the research samples, Mechanical properties were measured after irradiation of gamma rays emitted from the CO60 with energy rate of 1.33MeV and different irradiation doses (6,8,10) KGy. The results showed an increase in the hardness values after the irradiation compared with the results before irradiation while wear test showed a decrease in the values in normal conditions compare with the result after irradiation.
Assessment of natural radioactivity hazards in selected water samples collected from northern regions of Oman
Authors: Al-Harmali A
Published: April 2020

This study explores the radioactivity hazards in water samples collected from the Northern regions of Oman. The naturally occurring radioactive nuclides of the main series, 238U, 232Th, 235U and 40k have been studied by means of low level gamma spectroscopy. Majority of the studied valleys (wadis) are descending from Super Hajar Mountains either towards its east part (coastal area) or the west part (desert). Water samples were analyzed by applying the same analysis technique and ranges of concentrations of 238U, 232Th, 235U and 40K were found to be (0.35-1.7), (<DL-0.17), (0.01-0.18) and (0.26-0.91) all in Bq.L-1 respectively. The radiological hazards, D, HR and Raeq were calculated and found at ranges (0.21-7.94) nGy/h, (3.0-9.0)*10−4 mSv/yr and (0.02-3.6) Bq.L−1 respectively. The Hin, Hex and Iγr results were less than 1. The assessment of radioactivity in water samples showed values lower than world-wide average according to (WHO. The results indicate that the radiation hazard from naturally and artificially radionuclides in water samples from the area studied in this current work is barely significant.
Investigation of the existence of new nuclear magic number in even-even O isotopes using shell model and Hartree–Fock Bogoliubov method
Authors: Allawi Redhab A , Alzubadi Ali A
Published: April 2020

In the present work, the features of some excited states in some even–even 14-26O isotopes have been investigated. The aim is to predict the evaluated existence of magic numbers in these isotopes using shell model and Hartree-Fock Bogoliubov method based on SLy4, SkC, SkD Skyrme parameterizations. In particular, root mean square radius, binding energies, one and two neutron separation energies, pairing gaps, transition probabilities, excitation energies, energy levels, transition densities and quadrupole deformation parameters have been investigated. The results are compared with the available experimental data.
Study of effect reinforcement by coconut fiber on some mechanical and physical properties of thermoset polymer
Authors: Hashim S. M , Salih W. B
Published: April 2020

In this paper, a polymeric composite consisting of unsaturated polyester resin as a base material reinforced with coconut fiber was produced by volumetric fractions percentage ( 0%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3% ) of coconut fiber and at room temperature. The properties of compressive strength, hardness and thermal conductivity of the composite material were studied. The results showed an improvement in the mechanical properties ( compressive strength and hardness ) while the thermal conductivity values decreased with the increase of the volumetric fraction of the fibers. The heat insulation of the composite material is increased with the increase of the volumetric fracture of the fiber..
Study of the Spectroscopic Performance of Laser Produced CdTe, and CdTe:Ag Plasma
Authors: Naeema N , Kudher A , Mohammed Ghuson H
Published: April 2020

This article, plasma parameters [((Te) electron temperature, (ne) electron density, (fp) Plasma frequency, (λD) Debye length, and (ND) Debye number], were studied by using a spectrometer that collects the laser spectrum produces cadmium telluride Plasma in different energies. As well as for CdTe: Ag for different card ratios. The electron temperature results for the CdTe range (0.699-0.738 ) ev also has an electron density of ( 2.867-4.430)* 1018Cm −3 was measured under vacuum up to 2.5 x 10−2 mbar. As well as for CdTe:AgTe range (0.738, 0.606) and ne range(4.430-4.691) )* 1018 Cm −3.The properties of CdTe and CdTe: Ag were determined throughoptical transmission method using the ultraviolet spectral spectrum inside range 190-1100 nm.
Influence of titanium oxide additions with co2 laser treatment on the microstructural properties of glazes layer-dental zirconia ceramics
Authors: Salman Z A , Zaidan Sh A , Hubeatir K A
Published: April 2020

This paper presents the effect of CO2 laser on the glazes layer-dental zirconia ceramics after adding TiO2 nanoparticles to the glazes and study the its improvement. The specimens has been prepared by using CAD/CAM dental machine and sintered at 1530°C. Then the surface was glazed by VITA Glaze with (5% and 10%) of nano-TiO2 additions. The glaze layer were irradiated by continuous CO2 laser of 15Watt as indicated power. It was found that the main phases of the ceramic substrate are tetragonal zirconia with a percentage of alumina in the corundum phase. The glazing of the ceramic substrate led to a change in the X-ray diffraction pattern by the emergence of new phases, thus changing the crystallite size and percentage of lattice strain. The change in grain size measured by AFM technique, ranging from 88.46 nm to nm 62.18 in addition to changing surface roughness due to the emergence of centers of nuclei and grain growth. Moreover, the addition of TiO2 and laser irradiation changed the residual stresses on the surface, and this was reflected in the increasing hardness values from 575 kg/mm2 to 1215 kg/mm2 after added 5% TiO2 with laser treatment. Generally, addition of 5% TiO2 is better than 10% in terms the structure of the glaze layer surface and hardness, as the additions of 10% need a higher glazing temperature.
Structural and optical properties of Ag2S nanotubes prepared by laser ablation in liquid
Authors: Rawdhan Hanan A. , Ahmed Duha S. , Ismail Raid A.
Published: April 2020

Synthesis of Ag2S nanotubes (NTs) by laser ablation of silver target in Thiourea (Tu) aqueous solution without using catalyst was demonstrated. The structure, morphology, size and elemental composition of Ag2S NTs were investigated. X-ray diffraction (XRD) results show that the Ag2S NTs are crystalline with monoclinic phase. The optical energy gap of Ag2S NTs is around 1.6 eV at fluence 4.7 Jcm−2. Transmission electron microscope TEM investigation reveals the formation of NTs Ag2S morphologies with the diameter of 26-30 nm and lengths of 200-400 nm. Raman spectra of Ag2S nanorods show the presence of active Raman peaks indexed to Ag modes and the stretching bending Ag-S bonds and 2LO mode of Ag2S.
Adopting Texture Features to Detect and Recognize Brain Tumors in Magnetic Resonance Images
Authors: Derea Aya S , Abbas Heba Kh , Al-Saleh Anwar H , Mohamad Haidar J
Published: April 2020

The detection and recognition of tumor have a very important role in many applications of medical imaging. The use of computer in this process required high accuracy as it relates to human life especially that the error rate should be as low as possible. In this paper, Magnetic Resonance Imaging (MRI) images are tested using image processing (segmentation-based threshold) and supervised classification (minimum distance) to detect the region of interest. The location of the tumor is located using histogram algorithm with run length features. The geometric measurements calculated to identify tumors dimensions, location, volume and area. The results were highly efficient and highly accurate to determine the location and dimensions of the tumor.
Using spatial analysis techniques to Preparing maps for distribution of pollutant concentrations in Shatt al-Arab waters in November 2015
Authors: Khanger E.F. , Al Razaq B. A. , Ismail R. R. , Rasheed Z. F.
Published: April 2020

Water has a great self-generating capacity that can neutralize the polluting interventions carried out by humans. However, if human activities continue this uncontrolled and unsustainable exploitation of this resource, this regenerating capacity shall fail and it will be jeopardized definitively. Shatt Al-Arab River in South of Iraq. It has an active role in providing water for irrigation, industry, domestic use and a commercial gateway to Iraq. in the last five years Shatt Al-Arab suffered from a rise in pollutants due to the severe decline in sewage networks, irregular networks and pesticide products, as well as the outputs of factories and companies that find their way to water sources and lead to a widespread collapse of water quality. In present work, by using Data observation with the integration between remote sensing and GIS techniques to prepare maps of the distribution of concentration materials in Shatt al-Arab River south of the province of Basra in January 2015 to determine the level of pollution in the river. These include pH, dissolved oxygen (DO2), phosphates (PO4), nitrates (NO3), calcium, magnesium, potassium, Total soluble solids (TDS), electrical conductivity (EC) as well as alkaline salts (ALK.) The quality of polluted water has been observed at the sites of the study due to the increase in wastewater flowing into the river, especially river branches and the illegal discharges of industrial waste and sewage. In addition to the severe shortage of water levels in the last five years.
Characterization of nickel oxide nanocatalyst electrodes for an alkaline fuel cell
Authors: Ali N. A. , Mohammed H. J.
Published: April 2020

In this paper had been studied the characterization of the nanocatalyst (NiO) Mesh electrodes. For fuel cell. The catalyst is prepared and also the electrodes The structural were studied through the analysis of X-ray diffraction of the prepared nanocatalyst for determining the yielding phase and atomic force microscope to identify the roughness of prepared catalyst surface, Use has been nanocatalyst led to optimization of cell voltage, current densities & power for a fuel cell.
Effect of RTV Silicon Rubber on Some Mechanical Properties of Epoxy/Polyester Polymer Blends
Authors: Farhan Ahmed J , Jaffer Harith I
Published: April 2020

In this research the epoxy/RTVsilicon rubber and unsaturated polyester / RTVsilicon rubber blends were prepared by adding varying weight (3,5, 7,10 and 20)% of (SR ) to either of EP and UPE resins.The aim of research to analyze effect of RTV silicone rubber composition (3, 5, 7, 10 and 20) wt% of the mechanical properties of the epoxy and unsaturated polyester. Mechanical propertiessuch as impact strength, shore D hardness, young modulusand flexural strength were tested.The experimental results showed that the specimensof EP/SR and UPE/SR blends have a maximum values of impact strength (8.13 KJ/m2 and 11.91 KJ/m2) at the addition of 10% SR and 5% SR respectively.Hardness No. decreased slightly when the content of SR increased at a range of 3% to 20% in both of EP/SR and UPE/SR.Also flexural strength decreased rapidly when the content of SR increased at a range of 3% to 20% in both of EP/SR and UPE/SR.
Annealing temperature effects on the performance of the perovskite solar cells
Authors: Al-Mousoi A. K. , Mehde M. S. , Al-Gebori A. M.
Published: April 2020

In this work, perovskite solar cells were fabricated with one-step method by using spin coating technique. These solar cells were in the structure form of FTO/compactTiO2/mesoporousTiO2/CH3NH3PbI3/Au. Different annealing temperatures were applied to investigate the effect of the annealing temperature on the properties of the fabricated solar cells since it lead to affect the crystallization degree of the CH3NH3PbI3 layer. Three temperatures were used for annealing the perovskite layer typically: 60°C, 80°C and 100°C and the best result found at 100 °C where the efficiency was 5.68%, FF = 0.55, Jsc = 12.637 mA/cm2 and Voc = 0.817 V.
A novel Software Tool for Sizing Off-Grid PV System and PV/Diesel Hybrid System
Authors: Hashim Saja Majeed , Abdulateef Osamah Fadhil , Mustafa Falah I.
Published: April 2020

The design of graphical user interface programming is for sizing the components of a stand-alone PV system and PV-Diesel hybrid power system based on Iraq conditions. This software program presents as a guideline tool for photovoltaic system integrated depends on the input data by the user to give correct results according to the weather condition of solar radiation of Iraq, with less time and effort. A stand-alone solar system design model applied firstly, on a software program is to provide the load with energy 300Wh/day. Secondly, as an experimental application, to identify the appropriate factors that must be entered in the program from average solar irradiation and safety factor, by test the performance of the photovoltaic solar system, where the generation energy rate by the solar module was 381Wh and the consumption energy rate was 250.33Wh during the working period. The system will suffer from a lack of power generation if solar irradiation is not high enough or in case of weather conditions change.
Building a spin coater device for thin-film preparation
Authors: Ali F H
Published: April 2020

A low cost, simple design of the rotary spindle (spin-coater) is described in this research. This simple coating system is used as thin films deposition device for microscope slide (75*25) mm. The easily system can be built by electronics and machine. Designed with a brushless engine with Arduino Uno, designed for speed control. The rotational speed ranges from 350 to 10,000 rpm to give us many thickness according to the materials used. In our design, the rotational speed is controlled manually by the variable resistor.
The Influence of x ratio and Annealing Temperatures on Structural and Optical Properties for (CuO)x(ZnO)1-x Composite Thin Films Prepared by PLD
Authors: Nasir E M , Alias M F A , Mohammed Ali A N
Published: April 2020

Thin films of (CuO)x(ZnO)1-x composite were prepared by pulsed laser deposition technique and x ratio of 0≤ x ≤ 0.8 on clean corning glass substrate at room temperatures (RT) and annealed at 373 and 473K. The X-ray diffraction (XRD) analysis indicated that all prepared films have polycrystalline nature and the phase change from ZnO hexagonal wurtzite to CuO monoclinic structure with increasing x ratio. The deposited films were optically characterized by UV-VIS spectroscopy. The optical measurements showed that (CuO)x(ZnO)1-x films have direct energy gap. The energy band gaps of prepared thin films decreased as x ratio increased, while they increased with increasing annealing temperatures. Also the optical constants such as refractive index, extinction coefficient and dielectric constants have been calculated.
The Impact of Silver: Gold Nanoparticles Ratio on its Structural, Morphological and Optical Properties
Authors: Alias M. F. A. , Rashed KH. M.
Published: April 2020

The rapid development of nanomaterial applications has prompted the researchers to explore the possibility of controlling their properties. In this work, synthesize of silver: gold alloys (Ag: Au) nanoparticles by pulsed laser ablation in distilled water. Changing the ratio of the used target alloys (Ag: Au) lead to control the band wavelength of the plasmon frequency resonance. Atomic analysis shows decrease in the percentage of gold than its initial values using energy dispersive x-ray spectroscopy. The absorption spectrum illustrates the plasmon peaks in the visible range changes from 404 nm to 524 nm by changing the ratio of Ag: Au from 100:0 to 0:100 using UV-VIS spectrophotometer. The scanning electron microscopy indicates a change in the size of the NPs and achieves regular volume, especially for 50:50 ratios.
Preparation and characterization of equiatomic NiTi shape memory alloy
Authors: Mohammed M A , Aljubouri A A , Mohammed S H
Published: April 2020

The present study investigated the vacuum induction melting of equiatomic NiTi (Ni 50 at. %, Ti 50at. %) shape memory alloy using graphite crucible. The cast alloy heat-treated at 865° C for 15 mints, followed by quenching the sample in icy water. The microstructure and micro hardness of alloy were investigated before and after heat treatment by using an optical microscope and Vickers micro hardness tester. Transformation temperatures upon heating/cooling were investigated by using differential scanning calorimeter (DSC). Scanning electron microscope (SEM) supported with energy dispersive X-ray (EDX) and X-ray diffraction analysis (XRD) were carried out to investigate the chemical composition and the phases present in the alloy after heat treatment. The results show that the vacuum induction melting process in a graphite crucible provides binary NiTi shape memory alloys with good chemical homogeneity. The microstructure becomes more homogenous and the Vickers’s micro hardness increases from 186.06 to 238.74 after heat treatment with highly controlling on the composition of the alloy. The DSC curve shows that the R- phase exists upon the heating and cooling process. In addition the precipitate phase Ti2Ni was also exist.
Using Remote Sensing and GIS in Measuring Vegetation Cover Change from Satellite Imagery in Mosul City, North of Iraq
Authors: Allawai M. F. , Ahmed B. A.
Published: April 2020

The aim of the study is the assessment of changes in the land cover within Mosul City in the north of Iraq using Geographic Information Systems (GIS) and remote sensing techniques during the period (2014-2018). Satellite images of the Landsat 8 on this period have been selected to classify images in order to measure normalized difference vegetation index (NDVI) to assess land cover changes within Mosul City. The results indicated that the vegetative distribution ratio in 2014 is 4.98% of the total area under study, decreased to 4.77% in 2015 and then decreased to 4.54 % in 2016, after then decreased to 3,59% in 2017,then increased to 4.39% in 2018. Land cover change of the area was identified using Normalized Difference Vegetation Index (NDVI) technique. Highest NDVI value was found in 2015 (6.26%) which denotes presence of moderate-high vegetation cover at that time period. After 2015, highest NDVI value was found following a decreasing trend (6.05% in 2016 and 5.96% in 2018) which clearly represents the vegetation cover change in the study area, also Green Normalized. Difference Vegetation Index (GNDVI) is studied in this paper. Statistical properties for NDVI and GNDVI were illustrated has been computed. From the results of this study one can clearly notice that there are the spatial variation in the vegetal cover from 2014 to 2018 in Mosul city, north of Iraq.
Effect of sintering temperature on superconducting properties of Bi2Pb2Sr2Ca2Cu3-xCoxO10+δ system
Authors: Jassim A K , Abbas M M , Hussien A A
Published: April 2020

Bi2Pb0.3Sr2Ca2Cu3-xCoxO10+δ high temperature superconductors with x=0, 0.2 and 0.4 were prepared by a solid state reaction method. The samples properties have been investigated structurally by X-ray diffraction and morphologically by scanning electron microscopy. Structural analysis showed that two superconducting phases coexist in the samples high temperature Bi-2223 and low-temperature phase 2212 with orthorhombic structure for all samples. Four point probe method was used to study the electrical properties of the samples and all of them showed superconductivity behavior. The transition temperature increases with the increasing Co concentration and sintering temperature. Bi2Pb0.3Sr2Ca2Cu3-xCoxO10+δ superconductor sintered at 130 0C shows highest critical temperature 114 K.
Calculation Some Atomic Properties For Three and Four Electron Systems by Using Hartree- Fock Method
Authors: Hussien Wasan A
Published: April 2020

In this paper many physical properties evaluated like two particles radial density distribution function D (r1, r2), one-particle radial density distribution function D) (r1) has been evaluated by using Hartree-Fock type wave function for three and four electron systems (Li, Li−1, Be, Be+1, B+2) and the inter particle expectation values 〈r〉 has been evaluated too. Also it was calculation the expectation values for all energies 〈Ven〉, 〈Vee〉, 〈V〉, 〈T〉 and 〈EHF〉. All the results and the behaviors obtained in this work have been discussed, interpreted and compared with those previously obtained. It was found that the maximum of one-particle density distribution is shifting to the origin by increasing the atomic number (Z), due to the attraction forces between the nucleus and the electron clouds, As atomic number is Z increase, all the total energies are increases because the increasing nuclear charge effect. The results also indicate that attraction energy expectation values 〈Ven〉 are larger than the repulsion energy expectation value 〈Vee〉.
Anomalies in the magnetic properties of some terbium-yttrium iron garnets at low temperatures
Authors: Lahoubi M , Boutaba A
Published: April 2020

This work is aimed to study the influence of the replacement of the magnetic cations Tb3+ by diamagnetic cations Y3+ on the low-temperature point’, TB predicted by Belov for ferrimagnets with and without magnetic compensation point, Tcomp. Isothermal magnetizations, MT(H) are carried out on single crystals of two mixed terbium-yttrium ferrite garnets TbxY3-xFe5O12 (x = 1.98 and 0.37). The measurements are performed using DC magnetic field, H up to 80 kOe applied along the <111> and <100> crystallographic directions in the 1.5-300 temperature range. From the approximation to the second order of H, the expansion of MT(H) is analyzed on the basis of the T-dependences of the spontaneous magnetization, MS, the paraprocess magnetic susceptibility, χp and the parameter, |b| of the bH2 term. The manifestation of ferromagnetic-and antiferromagnetic-type low-temperature paraprocess and other concomitant effects is observed in the temperature dependences of the derivative, dMS/dT where MS exhibits Néel’s-type curves, i.e., N-type with Tcomp = 137 K for x = 1.98 and P-type without a Tcomp point for x = 0.37). It was established that low-T anomalies appear in the area of TB = 58 K reported before for the pure TbIG. The results obtained for x = 0.37 in the case of the free sphere show that |b| undergo changes at TSR1 = 40 K, TSR2 = 140 K, and TSR3 = 232 K. Thus, we suggest that as T increase, the previous spin reorientation phase transition occurs in a wide T-range, (40-232 K) from the easy axis of magnetization <100> via stable and intermediate low-symmetry angular phases  towards the high symmetry phase <111>.
Comparison Study of Some Mechanical Properties of Epoxy Composites usinguncarbonized Orange peel and Carbonized Orange peel
Authors: Hameed H K , Jassim W H.
Published: April 2020

Inthis investigation the epoxy was reinforced by orange peel and carbonized orange peel particles with percentages (5%, 10%, 15% and 20% by weight).Mechanical tests like:Tensile, flexural,Hardness, impact and compression were carried out on these natural epoxy composites. The results showed the tensile strength have a higher value by adding (15% by weight )of orange peel and carbonized orange peel particles to epoxy,while the value (10% by weight ) of addition is suitable to get improvement in the other mechanical properties as flexural strength, Hardness, impact and compressive strength. The epoxy / carbonized orange peel powder have the best valuesin all mechanical properties than that of epoxy/orange peel powder.
Effect Annealing Temperature on the Physical Properties of Cadmium Sulphide thin Films Deposited by using Thermal Evaporation Technique
Authors: Mohammed Jumaa , Abbas Jasim M. , Mustafa Falah I.
Published: April 2020

This study measured some of the structural, electrical and optical properties of cadmium sulfide (CdS) thin films with thickness of 150 nm deposited on glass substrate by using thermal evaporation system under vacuum pressure 1x10−5mbar. X-ray diffraction technology was used to analyses the structural properties of the CdS films. Results showed that the CdS films type cube polycrystalline structure and the preferred growth path was [111].In evaluating DC conductivity, we observed two mechanism of activation energy. In the measuring Hall effect shows that the electrical conductivity of the CdS films is negative carriers (n-type). The result of the (AFM) measurements showed that the grain size and average roughness increased with annealing temperature increased. In optical properties it were found that transmittance 80% at RT that decreases with increasing annealing temperature. It also found that absorption coefficient, extinction coefficient and refraction index increased with increasing annealing temperature. Optical energy gap were found decreased with increasing annealing temperature as (RT, 150 and 300 C°) the results (2.4, 2.38 and 2.32 eV) respectively. The results electrical properties showed that the CdS thin films had two activation energy and Hall effect were found that the mobility increase with increasing annealing temperature.
Innovative design solution for a blockade immobilizing long-barrel Mauser-type and related firearms
Authors: Dziubek I T , Kołodziej A , Talaśka K
Published: April 2020

The paper presents the design characteristics of a blockade immobilizing long-barrel Mauser-type and related firearms. The main functional feature of the blockade is securing the weapon from unauthorized use. This stems from the legal regulations that require each owner to secure the weapon from access by unauthorized persons. The design solution presented in this work, together with the assembly and disassembly kit, as well as the method of activation and deactivation are protected by patents: PL 230049, PL 229706 and PL 229807. The design features of the individual elements of the blockade, through which the entire assembly obtains its expected functionality, have been defined. The influence of changes in the selected geometric parameters of the main elements on the efficiency of the blockade is presented. The presented results of design work confirm the effectiveness and reliability of the presented weapon blockade.
The impact of support points during the measurement of machine tool bodies on Coordinate Measuring Machines
Authors: Michalski R , Kwiatkowski R
Published: April 2020

The article concern on the considerations regarding the influence of support points during measurement using coordinate measuring technique. The object of research, slide of the X axis of a five-axis numerically controlled machine CMX 70U from the portfolio of DMG MORI, produced at FAMOT Pleszew Sp. z o.o., set on the coordinate table of the measuring machine, using three- and four-point fixing. The aim of the research is to determine the optimal method of supporting the bodies, which in effect will reduce the measurement time and increase the efficiency of the process. The MES analysis available in the Creo software was used to calculate and graphically present the results.
Experimental research of the thermoplastic belt plasticizing process in the hot plate welding
Authors: Wałęsa K , Malujda I , Wilczyński D
Published: April 2020

Most of the industrial machines use belt transmission for power transfer. These mechanisms often use the round belts with a few millimeters in diameter, which are made of thermoplastic elastomers, especially polyurethane. Their production process requires the bonding step, which is often performed via butt welding, using the hot plate. One of the most important parameters which describe this bonding phenomenon is plasticized distance. Identifying its value is necessary to predict the length reduction ratio of the belt during welding, and in consequence to evaluate the joint quality. To predict the quantity of plasticized material, which depends on a lot of process parameters, the physical model of plasticizing process should be designated. The experimental research of this phenomenon is helpful to estimate value of force which is necessary to perform plasticizing, and show the typical problems during this process. The paper presents the results of the round drive belts plasticizing attempts, for different diameters of the belt, which were performed using the strength test station and heating device. In conclusion of the paper, there is the correlation between plasticizing force, velocity and distance.
Multifactor analysis of experiment parameters on the example of the biomass cutting process
Authors: Wilczyński D
Published: April 2020

The paper presents a multifaceted analysis of variance of the biomass cutting process parameters. First of all, the results of the cutting process were presented as the obtained output based on the change in parameters in the form of knife sharpening angle, knife rake angle and moisture content of cutter material. These parameters constituted input factors for the analysis of their impact on the output value in the form of cutting force and analysis of the impact of each of the factors (parameters) on the interaction between the other factors (parameters). For this purpose, the ANOVA multifactor analysis method implemented in the Design-Expert software was used. The analysis made is an example of showing the impact of particular parameters on the cutting force, but also proves the possibility of limiting the number of experiments, giving the possibility of forecasting (determining) the output for parameter values not taken into account in the experiment. This allows to establish and determine new answers without the need to perform new experiments, but also to plan new, better-oriented goals in the form of finding the right answer value, which would be the value of the cutting force in relation to the discussed experiment.