bluuebunny/crossref_metadata_2025 huggingface dataset:
Double-shock-induced spall and recompression processes in copper
Authors: Wang JiaNan , Wu FengChao , Wang Pei , He AnMin , Wu HengAn
Published: April 2020

Spall damage caused by multiple shockwaves is a crucial and significant issue worth exploring. Herein, we perform molecular dynamics simulations to investigate shock damage and the recompression process in double-shock-loaded copper. Compared to the traditional spall signal, two significant velocity peaks with different time intervals between peaks are observed in the free-surface velocities under two shock loadings. The dynamic processes are then revealed via the evolution of voids and the complex propagation of waves. Meanwhile, the states of the recovered samples after shock loading are found to depend on the loading conditions. Both intact samples that undergo recompression and broken samples with separated spall scabs are observed in our simulations. Secondary spallation is observed after the recompression process, and the associated spall strength is significantly lower than that under the first shock loading. Recrystallization is observed in the spall region after secondary shock loading with a remnant of highly localized plastic deformation. The simulation results are confirmed based on the thermodynamic properties of the samples obtained via the temperature–pressure pathway.
Reduced-order modeling of dynamic stall using neuro-fuzzy inference system and orthogonal functions
Authors: Tatar Massoud , Sabour Mohammad Hossein
Published: April 2020

To consider stall flutter in the design procedure of a blade, accurate models of flow loading are needed. This paper first presents a numerical simulation of an airfoil undergoing a deep dynamic stall employing a computational fluid dynamics code. Overset and polyhedral grid techniques are adopted to accurately simulate the flow field at high angles of attack. Having validated the simulation, the occurrence of stall flutter over a pitching airfoil with an increase in amplitude and frequency of oscillations is examined. The results express that the amplitude of the lift and pitching moment depends on the amplitude of the forced oscillation and there are higher harmonics of the pitching moment compared to the forced oscillation frequency content, both indicating the nonlinearity of aerodynamic lift and pitching moment. Subsequently, a nonlinear reduced model of the dynamic stall is derived using a fuzzy inference system (FIS) and the adaptive network-based FIS (ANFIS). Due to the unsatisfactory results of modeling, especially at post-stall angles of attack, the Gram–Schmidt orthogonalization technique is used to construct a more complex structure of the input variables. The new higher-order input variables have been re-employed by FIS and ANFIS. The results show that excellent modeling is achieved by ANFIS between the new structure of the inputs and the corresponding aerodynamic coefficients using only 10% of input–output data. Having found an appropriate relation, the proposed reduced-order model could properly predict the aerodynamic response of the pitching airfoil at two reduced frequencies.
Surveying the free energy landscape of clusters of attractive colloidal spheres
Authors: Huang Shanghui , Quevillon Michael J. , Kyhl Soren , Whitmer Jonathan K.
Published: April 2020

Controlling the assembly of colloidal particles into specific structures has been a long-term goal of the soft materials community. Much can be learned about the process of self-assembly by examining the early stage assembly into clusters. For the simple case of hard spheres with short-range attractions, the rigid clusters of N particles (where N is small) have been enumerated theoretically and tested experimentally. Less is known, however, about how the free energy landscapes are altered when the inter-particle potential is long-ranged. In this work, we demonstrate how adaptive biasing in molecular simulations may be used to pinpoint shifts in the stability of colloidal clusters as the inter-particle potential is varied. We also discuss the generality of our techniques and strategies for application to related molecular systems.
Extreme escape from a cusp: When does geometry matter for the fastest Brownian particles moving in crowded cellular environments?
Authors: Basnayake K. , Holcman D.
Published: April 2020

We study here the extreme statistics of Brownian particles escaping from a cusp funnel: the fastest Brownian particles among n follow an ensemble of optimal trajectories located near the shortest path from the source to the target. For the time of such first arrivers, we derive an asymptotic formula that differs from the mean first passage times obtained for classical narrow escape and dire strait. When particles are initially distributed at a given distance from a cusp, the time of the fastest particles depends on the cusp geometry. Therefore, when many particles diffuse around impermeable obstacles, the geometry plays a role in the time it takes to reach a target. In the context of cellular transduction with signaling molecules, having to escape from such cusp-like domains slows down signaling pathways. Consequently, generating multiple copies of the same molecule enables molecular signals to be delivered through crowded environments in sufficient time.
Dynamics of a viscoelastic liquid filament connected to two mobile droplets
Authors: Zhou Jiajia , Doi Masao
Published: April 2020

A filament of liquid is usually unstable and breaks up into small droplets, while a filament of polymer solution is known to be quite stable against such instability, and they form a stable configuration of a filament connecting two spherical droplets. If the droplets are fixed in space, the liquid flows from the filament region to the droplet region to reduce the surface energy and the filament gets thinner. If the whole liquid is placed in another viscous fluid, the droplets approach each other and the filament can get thicker. Here, we study the dynamics of such a system. We derive time evolution equations for the radius and the length of the filament taking into account the fluid flux from the filament to the droplets and the motion of the droplets. We will show that (a) if the centers of the droplets are fixed, the filament thins following the classical prediction of Entov and Hinch and (b) if the droplets are mobile (subject to the Stokes drag in the viscous medium), the thinning of the filament is suppressed and, under certain conditions, the filament thickens. This theory explains the phenomena observed by Yang and Xu [“Coalescence of two viscoelastic droplets connected by a string,” Phys. Fluids 20, 043101 (2008)] in a four-roller mill device.
The interaction between tone and prosodic focus in Mandarin Chinese
Authors: Wang Ting , Liu Jun , Lee Yong-hun , Lee Yong-cheol
Published: April 2020

This study characterized focused tones in Mandarin Chinese through a production experiment using phone number strings. The results revealed that, although phonation cues had little effect on any focused tone, prosodic cues exhibited various patterns of distribution. Duration played an important role for each focused tone, but intensity had a relatively less salient role. Among pitch-related parameters, the raising of pitch register was an important cue when a level tone (tone 1) was focused. By contrast, due to the interaction between tone and intonation, absolute slope and pitch range had less effect on tone 1 focus. These cues, however, were prominent when contour tones (tones 2 and 4) were in focus. Unlike other focused tones that raised pitch, tone 3 focus exhibited the opposite pattern, lowering its pitch target. In the aggregation of all focused tones, it was found that only primarily pitch-related parameters were selected as the main variables discriminating one from another. The results of this study, therefore, suggest that the prosodic marking of focus is not uniform, even within a single language, but clearly differs by tone type. Accordingly, prosodic marking of focus should be considered multimodal in a tonal language.
Constructing realistic effective spin Hamiltonians with machine learning approaches
Authors: Li Xue-Yang , Lou Feng , Gong Xin-Gao , Xiang Hongjun
Published: April 2020

The effective Hamiltonian method has recently received considerable attention due to its power to deal with finite-temperature problems and large-scale systems. In this work, we put forward a machine learning (ML) approach to generate realistic effective Hamiltonians. In order to find out the important interactions among many possible terms, we propose some new techniques. In particular, we suggest a new criterion to select models with less parameters using a penalty factor instead of the commonly-adopted additional penalty term, and we improve the efficiency of variable selection algorithms by estimating the importance of each possible parameter by its relative uncertainty and the error induced in the parameter reduction. We also employ a testing set and optionally a validation set to help prevent over-fitting problems. To verify the reliability and usefulness of our approach, we take two-dimensional MnO and three-dimensional TbMnO3 as examples. In the case of TbMnO3, our approach not only reproduces the known results that the Heisenberg, biquadratic, and ring exchange interactions are the major spin interactions, but also finds out that the next most important spin interactions are three-body fourth-order interactions. In both cases, we obtain effective spin Hamiltonians with high fitting accuracy. These tests suggest that our ML approach is powerful for identifying the effective spin Hamiltonians. Our ML approach is general so that it can be adopted to construct other effective Hamiltonians.
The research of the effectiveness of the ice cover destruction by the resonance method from the pair motion of the load
Authors: Zemlyak V L , Rogozhnikova E G , Vasilyev A S , Radionov S V
Published: April 2020

In the work, the efficiency of study of the ice cover by the resonant method from the pair movement of the load is experimentally investigated. Studies were conducted in the experimental ice tank. At the initial stage of the study, a series of experiments was conducted to determine the effect of the mass of the load on the parameters of flexural-gravity waves generated in model ice. Further, the effect of the distance between the load models during their pair wake movement was studied. Study have shown that, depending on the distance between the models, either an increase or a decrease in the effectiveness of ice cover destruction was observed by flexural-gravity waves, which is associated with the interference phenomenon — an increase and decrease in the resulting amplitude of two coherent wave systems generated from the motion of the models. In general, it can be concluded that, to increase the efficiency of the resonant method of breaking the ice, flexural-gravity waves can be used as repeated passes of a single load across the ice cover, as well as pair movement.
The relative thickness of the barriers and its fundamental importance in armored ballistics
Authors: Popov Yu V , Markov V A , Pusev V I , Selivanov V V
Published: April 2020

The issues of armor ballistics related to attempts to classify the types of deformation and destruction of barriers during perforation and penetration are considered. It is shown that the published classification options were not accompanied by the relative thickness of the barriers, determined by the ratio of the thickness of the barrier to the diameter of the impactor. In this regard, in some cases, the assessment of the thickness of the barriers is either humanitarian-emotional in nature, or is an erroneous quantitative assessment. Corresponding examples are given, and the classifications are supplemented by the relative thickness of the barriers. The features of evaluating the processes of perforation and penetration for caliber and sub-caliber projectiles, as well as for cumulative jets, are considered.
Non-isothermal synthesis of materials based on the MAX phases in the Ti-Si-C and Nb-Al-C systems
Authors: Afanasyev N I , Lepakova O K , Kitler V D
Published: April 2020

The experimental results of self-propagating high-temperature synthesis of materials in Ti – Si – C and Nb – Al – C systems are presented. Mixtures of powders of Ti, Si, Nb, Al, and C were used as charge. The combustion thermograms of the Ti-Si-C system are investigated. It is shown that changes in the technological conditions of synthesis can substantially change the phase composition and microstructure of the final products. The optimal synthesis conditions were established, which made it possible to obtain a product with a maximum content of the target phases Ti3SiC2, Nb2AlC, Nb4AlC3. Under all conditions studied, the SHS method fails to obtain 100% of the MAX phase of stoichiometric composition. To obtain 100% stoichiometric MAX phases, additional heat treatment of the ground SHS products is necessary. The products obtained by high-temperature synthesis were characterized by X-ray, optical and scanning electron microstructural analysis methods.
Permeability of membranes stacked tightly closed carbon nanotubes
Authors: Chelnokova A S
Published: April 2020

Nanotubes, like fullerenes, can be stacked in potential wells of adjacent tubes, forming a new material with triangular tunnels. This method of cluster formation from nanotubes is called self-laying mode. In this work two methods for calculating permeability of such material by the molecules and atoms of a gas mixture are proposed. In the framework of the first approach, the calculations made it possible to determine the effective radii of the tubes with respect to helium and methane. This method relies on the determination of the sizes of the areas of free passage of molecules, the second on a set of complete statistics on single launches that realize the passage of molecules. The studied ideal carbon structure showed high selectivity with respect to the separation of the methane-helium mixture and was practically impermeable to methane.
Calibration methodology of program package for optic measuring of strain and crack resistance determination of compact tension specimens
Authors: Kozulin A A , Titkov V V , Kushnaryov A G
Published: April 2020

In the work, the problem of eccentric tension of a compact specimen with a crack was solved by numerical methods. It was proposed to use the results of numerical modeling for setting up and testing the original software package for measuring the deformation of materials by optical methods. The values of the fracture parameters obtained by software coincide with the experimental and numerical results. The proposed testing methodology made it possible to avoid problems with determining the error in the quality of calculation of the optical flow during verification. The dependences of the change of the values of stress intensity factor and J-integral on the applied tensile loading are determined for compact tension specimen with a crack from aluminum alloy D16.
Forced rotation of fullerenes in an electromagnetic fields
Authors: Bubenchikov A M , Bubenchikov M A , Mamontov D V , Lun-Fu A V
Published: April 2020

A mathematical model of molecular dynamics is presented, which allows one to study the behavior of molecular crystals both in electromagnetic fields and in the absence of fields. This model is universal and affordable, and also does not require high computing power. The fullerene-based materials continue to exhibit unique properties, and the applicability of such materials is steadily increasing. A study of fullerite in the solid phase with charged fullerenes was carried out, characteristic states of the substance were obtained, and their potential properties were analyzed. The potential use of the material is also described taking into account the properties obtained.
Study of the effect of the size of the initial nickel powder on the structure formation of the mixture during mechanical activation of titanium and nickel
Authors: Shkoda O A
Published: April 2020

The structure and morphology of the mechanoactivated powder mixture has significant impact on the process of further synthesis. In this paper, the influence of the sizes of the initial powders on the formation of the structure of the mechanoactivated powder mixture during mechanical activation and the formation of layered agglomerates in the powder mixture of titanium and nickel is studied. The evolution of the formation of the size and density of layered agglomerates with the participation of both small and large nickel powder after different times of mechanical activation is studied. The study showed that the mechanical activation process leads to the formation of layered agglomerates and an increase in activity, which is associated with an increase in the contact surface of dissimilar particles, the number of defects. It is established that the use of initial nickel of different dispersion contributes to the formation of different structure of mechanoactivated powder mixture.
High temperature synthesis of copper coatings made from a thin film layered composition “CuO -B - Glass”
Authors: Shulpekov A M , Lapshin O V
Published: April 2020

The study is aimed at developing methods for producing thin-layer cermet coatings. Such coatings are promising for use in flat heating elements, thermal protective coatings. A method for producing electrically conductive coatings based on copper and borosilicate glass using the technology of self-propagating high-temperature synthesis is proposed. The wave synthesis and thermal explosion in the CuO – B – glass thin-layer system were studied using experimental methods and developed mathematical models. The effect of the reaction layer thickness and inert additive on the kinetics of the process and characteristics of final products was studied. Numerical calculations were performed to study the dynamics of the process. The thermophysical and kinetic parameters that determine the synthesis in the CuO – B – glass system are found using the inverse method.
Quantifying process-level uncertainty contributions to TCRE and carbon budgets for meeting Paris Agreement climate targets
Authors: Jones Chris D , Friedlingstein Pierre
Published: April 2020

To achieve the goals of the Paris Agreement requires deep and rapid reductions in anthropogenic CO2 emissions, but uncertainty surrounds the magnitude and depth of reductions. Earth system models provide a means to quantify the link from emissions to global climate change. Using the concept of TCRE—the transient climate response to cumulative carbon emissions—we can estimate the remaining carbon budget to achieve 1.5 or 2 °C. But the uncertainty is large, and this hinders the usefulness of the concept. Uncertainty in carbon budgets associated with a given global temperature rise is determined by the physical Earth system, and therefore Earth system modelling has a clear and high priority remit to address and reduce this uncertainty. Here we explore multi-model carbon cycle simulations across three generations of Earth system models to quantitatively assess the sources of uncertainty which propagate through to TCRE. Our analysis brings new insights which will allow us to determine how we can better direct our research priorities in order to reduce this uncertainty. We emphasise that uses of carbon budget estimates must bear in mind the uncertainty stemming from the biogeophysical Earth system, and we recommend specific areas where the carbon cycle research community needs to re-focus activity in order to try to reduce this uncertainty. We conclude that we should revise focus from the climate feedback on the carbon cycle to place more emphasis on CO2 as the main driver of carbon sinks and their long-term behaviour. Our proposed framework will enable multiple constraints on components of the carbon cycle to propagate to constraints on remaining carbon budgets.
Studying the effect of Polyamide 6 Nanofibers on Physical and Chemical Properties of Unsaturated Polyester Reinforced by Glass fibers Composites
Authors: Al dabbagh B M , Kadhim H J , Salih R M
Published: April 2020

In this study, the hybrid reinforcement materials of (glass fibers and polyamide 6 nanofibers) with 15% weight fraction added to unsaturated polyester (UPS). The physical properties (density, bending strength, impact strength) and chemical resistance of UPS reinforced with of hybrid reinforcement (GF+PA6 nanofibers)with differen ratios: (0.99:0.01, 0.98:0.02, 0.97:0.03, &0.96:0.04) wt.% by 15% weight fraction were studied. Results proved that, the impact strength increased from 0.5 to 1.5 K.J/m2, while the bending strength increases from (2 to 14.5) MPa with adding of (0.96:0.04) wt.% of reinforcement materials by 15% weight fraction.The weight loss of (UPS/GF) decreased from (1 to 0.1) with (0.04) wt. % of PA6 Nanofibers for 30 days and it stable at this value for 40 days, this is refers to increases of chemical resistance of samples in H2SO4 acid. The density of (UPS/GF) decreased from (1.29 g/cm3) to (1.01) g/cm3 for density of (UPS/19.96GF+0.04 PA6 Nanofibers).
Fabrication Flexible Solar Cells by Organic Semiconductors
Authors: Abood M. A. , Mustafa Alattar F. I. , Badri M. S.
Published: April 2020

Organic semiconductors require low energy fabrication process coupled with the ease of processing, as well as compatibility with flexible substrates, hence, can be fabricated at low cost as light-weight solar cells. The thin films of Ni-PhthalocyanineTetrasulfonic acid tetrasodium salt and poly (3, 4- ethylenedioxythiophene) poly (styrenesulfonate) on indium tin oxide (ITO glass and plastic) substrates were prepared by drop casting at thickness (100 nm). The optical properties were studied by using UV-Vis absorption spectra. The current–voltage characteristics of solar were measured the efficiency values about 4.17%.
Film analysis and quality control from x-rays examinations in some hospitals in Baghdad
Authors: Alhamd M W , Alwan F J , Alobaidi W O , kamoon S S
Published: April 2020

There were significant correlation between breathing effects in chest x-ray examination and rejected film. While the techniques and skills employed contribute to about 50% nearly equally of the rejected films. The study samples included (300) patients divided males and females. The mean age of subjects was (35±10years), their mean height was (170±5 cm) and the mean weight was (70±5Kgm).
Spectral fluctuations in 24Mg nucleus using the framework of the nuclear shell model
Authors: Abdul Hussian Thoraia A , Hamoudi Adel K
Published: April 2020

Random matrix theory is used to study the chaotic properties in nuclear energy spectrum of the 24Mg nucleus. The excitation energies (which are the main object of this study) are obtained via performing shell model calculations using the OXBASH computer code together with an effective interaction of Wildenthal (W) in the isospin formalism. The 24Mg nucleus is assumed to have an inert 16O core with 8 nucleons (4protons and 4neutrons) move in the 1d5/2, 2s1/2 and 1d3/2 orbitals. The spectral fluctuations are studied by two statistical measures: the nearest neighbor level spacing distribution P(s) and the Dyson-Mehta statistics (∆3 statistics). For calculations with the full diagonalization of the Hamiltonian, the spectral fluctuations are found to be in agreement with the Gaussian orthogonal ensemble of random matrices.
Estimation the cancer risk due to ingestion the food spices commonly used in Iraqi kitchen
Authors: Al-Mashhadani A H , Yas R M , Majeed W z , Saeed A A , Naje N B , Abdul Hadi W
Published: April 2020

Spices are natural substances taken from special plants and have a different taste when added to food and some of them have great benefits for health and body. These plants vary from country to country depending on the type of soil and how they are grown and this affects their quality. In this study, the specific activity of40K,238U and232Th series and137Cs in some selected natural food spices commonly used in Iraq kitchen were determined using gamma spectrometry and the ingested doses via food consumption were also assessed. The average specific activity of40K,238U,232Th and137Cs in the samples are 72.00 Bqkg−1, 106.576Bqkg−1, 148.74 and 191.88 Bq.kg−1respectively. The highest activity concentration of40K,238U,232Th and137Cs was recorded in cumin (401.7) for40K, laurel paper (260.67) for238U, briana spices (733.7) for232Th and Chamomile (833.4) for137Cs. The maximum value of total annual effective dose received from40K,238U,232Th and137Cs due to consumption of natural spices by the inhabitants was 169.83 μSvy−1. This value is low compared to the average radiation dose of 290 μSvy−1received per caput worldwide due to ingestion the food spices. The excess lifetime cancer risk due to ingestion of radionuclide in food spices was estimated and the values obtained were compared with standards. Based on these results it can be concluded that the foods spices studied in this work do not present any serious radiological effect. Spices are natural substances taken from special plants and have a different taste when added
Computational analysis for electrical breakdown in air due to streamer discharge in rod-to-plane arrangement
Authors: Abd Alameer Maha F , Khalaf Thamir H
Published: April 2020

In addition to the theoretical and experimental, the numerical simulation is the third way to study the electrical discharge phenomenon. In this work, a numerical simulation was executed within a rod-to-plane electrodes arrangement to track the streamer discharge between the two electrodes for different rod dimensions and air gap length distances. The simulation results show the path of the streamer channels, and their branches, from the rod to the plane. Also, the electric potential and field distributions were presented as contour plots. The plots show clearly the sites of the streamer initiation and growth and how the distributions were affected by the streamer growth between the two electrodes. The dc applied voltage was variated, and the minimum value that caused the streamer to bridge the air gap and touch the plane was indicated as the breakdown voltage. It was found that, the breakdown voltage increased with the increasing of the air gap length distance, the electric field threshold value, the rod diameter, and less of that with the increasing of the rod lengths.
Numerical Analysis of CW Raman Amplifier in Silicon-on-Insulator Nano-Waveguides
Authors: Khaleefa Z S , Mahdi Sh S , Yaseen S Kh
Published: April 2020

Numerical analysis of continuous wave (CW) on-off optical Raman gain in Silicon-On-insulator (SOI) nano-waveguides has been investigated. Two types of waveguide structures rib and strip waveguides have been incorporated. The waveguide structures have designed to be 220 nm in height. Three different widths of (350, 450, 1000) nm were studied. At telecommunication wavelength of 1550 nm, Raman amplification was calculated to be about 65 dB in rib SOI waveguide. The obtained Raman amplification is the heist reported value at relatively low pump power. High Raman gain amplification in SOI nano-waveguides presents an important step towards integrated on-chip optoelectronic devices.
Diagnosis of copper plasma by laser induced breakdown spectroscopy
Authors: Saadoon N.M. , Hadi N.M. , Sabeeh S. H.
Published: April 2020

In this paper influence of laser energy on the emission spectrum of laser copper-interaction and plasma parameter for plasma Copper by used a first harmonic generated wavelength of Nd:YAG exaction source. The metal plasma that had detection by HR4000 detection system (ocean optics) was use to different excited. plasma temperature via the Boltzmann plot diagram with measuring the electron density number by McWhirter CRITERION. Values of measuring (Ne), (Te) found between (61178776 K°) and (Ne) is (1.77*1015, 2.01*1015 cm−3) at 1064nm.
Structural and Optical properties of CdTe:CuThin Films by Pulsed Laser Deposition technique
Authors: Naeema N , Kudher A , Mohammed Ghuson H
Published: April 2020

Polycrystalline cadimumtelluride : copper composite thin films were deposited on a glass substrate by pulsed laser deposition technique(PLD).Using Nd:YAG with 1064 nm wavelengthconstant energy 600 mJ, repetition rate (6) Hz and No. of pulse (150) for each sample.The pure of bulk (CdTe) and Mixture of bulk (CdTe:Cu) percentages (x=0.0, 0.3, 0.5 and 0.7)wt% were prepared. The structural, optical and morphological properties were inspected for the produced thin films.The energy band gap decreasing from 2.4 to 1.7eV with increase of Cu concentration. XRD patterns showed the domination of polycrystalline nature of cubic structure but in adding 0.5, and 0.7% Cu the nature of thin films became amorphous. AFM results demonstrated the increase of particle size from 73.66 nm to 76.67 nm at percentage of 0.5% Cu. The optical properties has been including the study of measuring the spectrum of transmittance, absorbance, Absorption coefficient (α), Optical Energy Gap (Eg), Reflectance (R), Refractive index, Extinction Coefficient, Dielectric Constant and Optical Conductivity (σ) of the wavelength range (320-1100) nm. The results have been show that the films have good transmittance for all films around 60-94% in the visible region and NIR of the spectrum that we can use them as optical windows in solar cells.
Functionalization, characterization, and antibacterial activity of single wall and multi wall carbon nanotubes
Authors: Mohammed M. K A , Mohammad M. R , Jabir M. S. , Ahmed D. S
Published: April 2020

The raw-SWNTs and raw-MWNTs were chemically oxidized with a mixture of sulfuric acid and nitric acid under ultrasonic vibration. The functionalized-SWNTs (F-SWNTs) and functionalized-MWNTs (F-MWNTs) were characterized by using ultra violet-visible spectrophotometer, X-ray diffraction, and field emission scanning electron microscopy (FESEM). The antibacterial efficiency of SWNTs and MWNTs towards Escherichia coli (E. coli) as gram-negative bacteria was evaluated via viable count method and fluorescence microscopy. The results of viable count method showed that the SWNTs and MWNTs have higher inhibitory effect after being treated with H2SO4/HNO3.The E. coli images under fluorescence microscopy exhibited that almost red color for dead cells, which confirms the efficient lethal ability of F-SWNTs and F-MWNTs.
Heterojunction Solar cell(NiPcTs/CdS)organic/inorganic
Authors: Hassan A S , Aboode M A , Shallal I H
Published: April 2020

In the present study, thin films of organic semiconductors Nickel PhthalocyanineTetrasulfonic Acid Tetrasodium Salt (NiPcTs) and inorganic semiconductor (CdS) prepared from the mixing of liquids for thesetwomaterials with different size ratios by the spin coating method on pre-patterned (Fluorine-doped Tin Oxide) FTO coated glass substrates and then the manufacture of solar cells. The properties of solar cells the study through the optical properties (absorption spectra, absorption coefficient, power gap) and electrical characteristics (continuous onductivity, Hall Effect and cell efficiency measurements) and Was obtainedThe efficiency of a multiple solar cell ranging from (0.16-13.2 %)
Morphological and Electrical Properties of Capped CdSe Nanoparticles
Authors: Mohammed Kahtan A , Al-Kabbi Alaa S , Ziadan Kareema M
Published: April 2020

In this study, cadmium selenide (CdSe) were synthesized by a chemical route process using complex agent ( tri sodium citrate ) as a ligand. cadmium acetate as a Cd source and Na2SeO3 as a Se precursor. The synthesized nanoparticles were characterized for their compositional, morphological and electrical properties using FESEM, EDAX and I-V characterization.
Evolution and set up the maps for solar radiation of Iraq using Data observation and Angstrom model during monthly July2017
Authors: Abed A f , Khanjer E F , Abdullah S A
Published: April 2020

The development that solar energy will have in the next years needs a reliable estimation of available solar energy resources. Several empirical models have been developed to calculate global solar radiation using various parameters such as extraterrestrial radiation, sunshine hours, albedo, maximum temperature, mean temperature, soil temperature, relative humidity, cloudiness, evaporation, total perceptible water, number of rainy days, and altitude and latitude. In present work i) First part has been calculated solar radiation from the daily values of the hours of sun duration using Angstrom model over the Iraq for at July 2017. The second part has been mapping the distribution of solar radiation energy to Iraq using interpolation technique in Arc _GIs software Version 10.3.
Fabrication and Development Low Cost Dual Axis Solar Tracking System
Authors: Farhan Ahmed Jadah
Published: April 2020

Solar energy is gaining importance day by day as an energy resource. By sun tracking we can increase the electric energy of solar panel. When the solar panel is perpendicular to the sun’s rays it receives more sunlight. This paper about follow the sunlight direction across the sky by using a DC motor(satellite motor), the LM324 IC control the movement of DC motor by this the solar panel will change their position, solar panel detects the sunlight using four light dependent resistors (LDRs). The objective is to design and implement an automatic solar-tracking mechanism using an embedded system design with minimum cost and reliable structure. The results presented in this review confirm that the azimuth and altitude dual axis tracking system is more efficient compared to other tracking systems.
Evaluation of some properties of polyetheretherketone composites used for biomedical applications
Authors: Mohammed A. A. , Al-Hassani E. S. , Oleiwi J. K.
Published: April 2020

Polyetheretherketone is considered to be a prime candidate with the potential to replace biomedical metallic materials as an orthopedic and dental implant on account of its elastic modulus similar to that of human cortical bone. This study presents the effect of polyetheretherketone specimens incorporated with different nano titanium dioxide and nano hydroxyapatite loading up to (1.5 wt%) have been prepared through a series of processing stages involving melt compounding, granulating and hot pressing. Following analysis of mechanical and chemical interactions by flexural, surface roughness and fourier transform infrared spectroscopy respectively. The results showed that the nano titanium dioxide and nano hydroxyapatite particles were uniformly disperse into polyetheretherketone, so the flexural modulus, flexural strength and surface roughness of polyetheretherketone biocomposites obviously increased with the addition of nano powder. On the other hand, break strain decreased with the rise of the total nano titanium dioxide and nano hydroxyapatite content. Furthermore, the best properties obtained when reinforced with nano hydroxyapatite.
Corrosion resistance of Ti6Al4V alloy by Radio Frequency Technique used for Coating Deposition of multilayer (HA/TiN/Ti6Al4V-substrate) for Optimization power
Authors: ulkareem M. A. , Noori F. T.M. , Khalaf M. K.
Published: April 2020

The objective of this study is to perform physical / chemical characterization and to determine the corrosion resistance of calcium-phosphate (HA), TiN-based bio-ceramics and thin metal plating processed by a Ti-6Al-4V process. TiN and HA coating maximum power 150 watts. The presence of TiN200 Watt TiN s coating resulted in electrochemical corrosion. High current cathodic and passive anodic polarization shows an active surface. EIS shows the active behavior assumed by the active cathodic currents imposed. And HA on the sample surface, some noise was observed during both polarization and EIS tests.
Friction and Wear Testing of Lubricated Joint Implant Material using AMTI Ortho-POD
Authors: Shamki A. I. , Abass S. J.
Published: April 2020

Friction and wear are caused by complex interactions between surfaces that are in mechanical contact and sliding against each other. The goal of this study was to determine the effect of different lubricants on the wear and friction of most commonly used implant material ultrahigh molecular weight polyethylene (UHMWPE), and to compare the results of UHMWPE with another materials polytetrafluoroethylene (PTFE). To accomplish this goal, pin-on-disk cyclic testing by AMTI Ortho-Pod pin on disk was used with lubricant. The lubricant used to mimic synovial fluid was bovine albumin, hyaluronic acid, and the artificial lubricant (silicone oil) were used. Gravimetric analysis was used to characterize wear after 700 thousand cycles at normal load 300 N, sliding velocity 87.92 mm/sec with different wear paths. Using these data, pin-on-disk wear tests were conducted to explore that circular path had a higher mean coefficient of frictions and specific wear rate than a line path. UHMWPE had a lower mean coefficient of frictions and specific wear rate than PTFE.
Determination of The Weibull Modulus by Electrical Breakdown and Mechanical Strength for Soda Lime Glass
Authors: Zaidan S A , Al Ani A Z
Published: April 2020

The interrelationships between mechanical and electrical properties are important to characterize one signifies the other, especially for brittle materials such as glass. The relationship between Weibull modulus from electrical breakdown and Weibull modulus from three-point bending test and other mechanical properties has been studied for soda lime glass slides. The results show that the electrical breakdown and Weibull modulus increased with the rate of rising voltage increases from 20.1-24.7 kV/mm and 10.9-13.78, respectively. The value of Weibull modulus was calculated by using mechanical strength is (12), this result identified the conditions necessary to achieve the same results in electrical breakdown strength test. Therefore, the best rate of rising voltage in the electric breakdown test is 2 kV/s which gives the same results as the mechanical tests. This means that it is possible in the future to evaluate the dielectric products electrically in terms of matching mechanical strength specifications using electrical tests.
Effect of Cold Atmospheric Pressure Plasma on Fertility Hormones for Female Rats
Authors: Yasoob A N , Khaleel K J , Murbat H H
Published: April 2020

The direct application of cold atmospheric plasma (CAP) is the main scope of plasma medicine in or on the organism for curative purposes. Cold plasma is both effective in disrupting a wide range of microorganisms including multiple drug resistant ones (MDRs) and to stimulate proliferation of mammalian cells. It has obtained by Floating Electrode Dielectric Barrier Discharge (FE-DBD) system. The present study aimed to show the effected of cold plasma on the fertility hormones LH, Prolactin, Estrogen, and Testosterone hormones for healthy adult female rats (Albino) / bulb c). There are divided into many groups according to time exposure of plasma (15, 30, 60, and 90 second) and a reference group (without plasma exposure), with different time intervals after exposure (1, 2, 3, 7, 14, 28 days). The concentration of hormones was measured using Enzyme Linked Immunosorbent Assay (ELISA). The results showed that, the CAP effected slightly on the Luteinizing Hormone (LH) and Estradiol Hormone (E2) the concentration levels slightly increased and stay near to the reference value for all times. Prolactin hormone (PRL) was effected significantly from the first day after exposure to CAP for all times, it was increased significantly (P < 0.0001) for short time of exposure (15, 30 sec) than control group value, and it was decreased significantly (P < 0.0001) than control value for time of exposure ( 60, 90 sec). The result of testosterone hormone is decreased significantly from the first day after exposure to CAP for all time exposure (15, 30, 60, and 90 sec).
The effect of the spinning speed variation on the perovskite solar cell efficiency
Authors: Mehde Mohammed S. , Al-Gebori Abdulnasser M. , Hantoosh Ali K.
Published: April 2020

In this work, compact titanitum dioxide (c-TiO2), amorphous titanitum dioxide (mp-TiO2) and methylammonium lead iodide (CH3NH3PbI3) films were prepared by spin coating method under different different rotational speed of the CH3NH3PbI3 films. Many characterization measurements were achieved on the deposited CH3NH3PbI3 films in order to study the change that resulted from different parameters. The X-ray diffraction (XRD) measurements revealed that the lattice constants of the fabricated CH3NH3PbI3 films were close to the slandered values. The atomic force microscopy (AFM) measurements were conducted in order to study the morphology of the fabricated CH3NH3PbI3 films at different scale, these results displayed that the grain size of the CH3NH3PbI3 films in the range between about 160nm to 210 nm. The field emiision scanning electron microscopy (FE-SEM) results of the fabricated CH3NH3PbI3 films were well agreed to the AFM result especially in the grains shape and distribution. Transmittance measurements have been done to determine the variation of the energy gap and absorption coefficient the CH3NH3PbI3 films. The structure form of the perovskite solar cells were FTO/c-TiO2/mp- TiO2/CH3NH3PbI3/Au, the C-V measurements were achieved to determine the built-in potential, which found to have the highest value when using 4000 rpm during the synthesis of the perovskite layer. In addition, the I-V measurements in dark conditions have been conducted to compute the ideality factor and the saturation current, which are considered important parameters that influences the characteristics of the solar cells. The best solar cell efficiency was obtained at spinning speed of 4000 rpm.
Effect of deformation parameters on microstructure evolution and properties of 33NiCrMoV15 steel
Authors: Barényi I , Krbaťa M , Majerík J , Mikušová I
Published: April 2020

The paper deals with the effect of temperature and strain rate to microstructure evolution and final hardness of 33NiCrMoV15 steel after the simulation of the deformation process on real samples using of dilatometer DIL805D. The main goal of the simulation is the evaluation of Peak Stress – deformation resistance for different deformation temperatures and rates. Measured values are also processed by regression analysis to define the mathematical model of the monitored dependency. Examined steel is high strength middle alloyed steel with an optimal level of plastic properties used for high loaded parts including howitzers and tanks gun barrels.
Influence of CNC milling strategies on complex surface machining
Authors: Dodok T , Čuboňová N , Císar M , Ivanov V , Wiecek D
Published: April 2020

Milling strategies are an integral part of CAD/CAM systems. Every CAD/CAM system offers unique strategies to differentiate itself from the competition. The article deals with analysis of CNC milling strategies in CAD/CAM system Edgecam 2017 R2. Analysis is divided into two parts. In first part are analysed roughing strategies with focus based on time necessary for removal of material. Second part is focused on finishing strategies and achieving the highest quality of surface. In conclusion, the article deals with the analysis of existing milling strategies and the creation of a database for the assignment of optimal roughing and finishing strategies for specified components.
The requirements for the design of dual-mass flywheels
Authors: Grega R , Jakubovičová L , Sága M
Published: April 2020

In the modern powertrains with new low emission combustion engines, the effort to reduce emissions and weight of the entire system increase the efficiency of vehicle drives but also make the drive much more sensitive to vibration. The new design concepts of dual-mass flywheels offer more options for eliminating vibration in vehicle drive systems. Every design of the dual-mass flywheel must ensure that it has the appropriate characteristics. A suitable characteristic then creates a prerequisite for application in a drive in which the resonance area can be moved to very low operating speed.
Reduction of the value of the bend deflection arising due to external forces and gravity by applying the tensile stress to the axial alignment
Authors: Knast P
Published: April 2020

The paper describes the methodology of designing geometric dimensions of elements of various structures h/L<0.01, where h means height and L length. It is useful for designing the optimum span of elements for which reaching the minimum value of f bend deflection is required. Creating an additional „artificial” stress acting axially in the direction perpendicular to the beam deflection reduces the value of the f bend deflection in a macro scale. The experiment has shown that the deflection of an element is minimised if the additionally applied force operating along the inert x axis is approximately 1 884 times greater than the forces causing the arrow to deflect in the y axis. The results confirmed that the introduction of an additional tensile force affecting an element in the system along the axis and the creation of an additional „artificial” tensile stress allows for reducing the bend deflection to 0. The developed methodology of designing geometrical elements h/L<0.01 consists in introducing additional forces causing stretching of the element along the x axis and checking the state of stresses in extreme fibres. If the fibres on both sides of the inert x axis are stretched, the deflection value on the macro scale is negligible.
Analysis of stability of stressed-skin constructions for transport of bulk raw materials
Authors: Dudziak M , Knast P , Talaśka K
Published: April 2020

An algorithm has been developed to assess the technical condition of stressed-skin constructions which constitute load-bearing structures and casing for conveyors. The description of the methodology is presented in the form of an algorithm. An important feature of the methodology is the measurement of main and intermediate structural nodes and then the comparison of measurement results with records in the documentation. The results of the measurements are used to simulate and assess the actual technical condition of the structure. If the deformation of the coating casing, ribbing, supports and other elements of the process line exceeds the limit values, it should be preventively decommissioned and assigned for repair or replacement. The developed methodology used for collecting the necessary information on the technical condition of the conveyor’s structure is aimed at its implementation to a wider use in industrial plants with developed inter-operational transport. The utilitarian aim of the study is to increase the level of users’ safety and to maintain the continuity of transport system performance.
Determination of the vibration emission level for a chipper with combustion engine
Authors: Kończak M , Kukla M , Warguła Ł , Talaśka K
Published: April 2020

Presently, we observe an increase in automation and mechanization of many areas of life and industry, which allow to increase work efficiency and reduce costs. However, many circumstances such as terrain shape, forestation or urban planning can prevent the deliver and operation of various types of machinery. Consequently, an important area of development for the basics of machine construction is non-road machinery. The high mobility and relatively low own weight allow operation in the most adverse conditions. One of such machines are chippers for wood branches. They are usually driven by combustion engines, which means they emit pollutants in the fuel combustion process together with noise and vibrations. All the above factors can negatively affect both the machine operator and the environment. It is therefore justified to examine the possibility to reduce the emission level of harmful media. This paper presents the results of study involving the measurement of vibration and noise generated during operation of a chipper with combustion engine under various operating conditions. The presented results will allow to identify the scale and place of origin of vibrations. They can act as a source of practical guidelines for the design of machines of this type.