bluuebunny/crossref_metadata_2025 huggingface dataset:
MNE responses to carbon pricing regulations: Theory and evidence
Authors: Nippa Michael , Patnaik Sanjay , Taussig Markus
Published: March 2021

This paper develops theory suggesting that, relative to purely domestic firms, multinational enterprises (MNE) have greater incentives and strategic and operational means to respond to expanding carbon emissions constraints. We test our resulting hypotheses with data on changes in carbon emissions by over 6,000 industrial plants during Phase 2 (2008–2012) of the European Union’s Emissions Trading Scheme. We find that MNE maintain: (1) consistent carbon reductions across institutional contexts, and (2) an overall carbon performance edge over domestic firms. The carbon performance gap between MNEs and domestic firms narrowed, however, in host countries transitioning towards more stringent market regulatory systems. By demonstrating that the effects of national and international carbon regulations on firm behavior interact in important ways with each other and with firm characteristics, this paper deepens understanding of how institutions are likely to shape the ongoing energy transition towards a low-carbon economy.
Is blue luminescence a fingerprint for good p-type conductivity in Mg-doped GaN?
Authors: Bandari Anashe
Published: March 2021

Researchers uncover the mechanism and origin of a mysterious blue luminescence band in an important semiconductor material.
Arbitrary EEDF determination of atmospheric-pressure plasma by applying machine learning to OES measurement
Authors: van der Gaag Thijs , Onishi Hiroshi , Akatsuka Hiroshi
Published: March 2021

A new method to determine the arbitrary electron energy distribution function (EEDF) from the optical emission spectroscopic measurement in atmospheric-pressure plasma is introduced. The optical emission spectroscopy (OES) continuum emission spectrum, dominated by electron-neutral bremsstrahlung radiation, is analyzed to inspect the usefulness of the conventional OES measurement range for EEDF determination. The EEDF is reconstructed from the OES continuum radiation spectrum by applying machine learning to solve the bremsstrahlung emissivity equation inversely. Through iterative statistical analysis, the presented genetic algorithm can locate the EEDF reliably. Verification of the algorithm shows that theoretical Maxwellian and Druyvesteynian EEDFs can be partially reconstructed from a realistic OES measurement range. Furthermore, preliminary experimental EEDF results of an argon dielectric barrier discharge (DBD) OES measurement are given. The electron energy range and resolution of the determined EEDF are discussed. The results in this paper show potential for accurate determination of the arbitrary EEDF in atmospheric-pressure plasma using simple OES equipment.
Noise effects on the Wilczek–Zee geometric phase
Authors: Aguilar Pedro , Chryssomalakos Chryssomalis , Guzmán-González Edgar
Published: March 2021

Non-Abelian geometric phases have been proposed as an essential ingredient in logical gate implementation—their geometric nature guarantees their invariance under reparameterizations of the associated cyclic path in parameter space. However, they are still dependent on deformations of that path due to noise. The first question that we tackle in this work is how to quantify in a meaningful way this effect of noise, focusing, for concreteness, on the nuclear quadrupole resonance Hamiltonian—other systems of this nature can clearly be treated analogously. We consider a precessing magnetic field that drives adiabatically a degenerate doublet and is subjected to noise, the effects of which on the Wilczek–Zee holonomy are computed analytically. A critical review of previous related works reveals a series of assumptions, such as sudden jumps in the field, or the presence of white noise, that might violate adiabaticity. We propose a state-independent measure of the effect and then consider sinusoidal noise in the field of random amplitude and phase. We find that all integer noise frequencies m ≠ 2 behave similarly in a manner reminiscent of the Abelian case, but that noise of frequency m = 2 has a very different and, at the same time, very pronounced effect, which might well affect robustness estimations.
Characterization of vortical structures in T-shaped branches depending on shear-thinning
Authors: Kim Junkyu , Ahn Junsun , Kim Hyoungsoo
Published: March 2021

The characteristics of vortical structures in T-shaped branches with respect to the shear-thinning effect are numerically investigated using a power-law fluid model. By varying the power-law index n, we observe three different flow structures, namely, steady-, harmonic-, and turbulent-like regimes. The time-averaged and instantaneous vortical structures are examined for different values of the local Reynolds number. In the steady regime, stationary vortical structures form near the corners of the T-shaped branch. As n decreases, the vortical structures oscillate back and forth, giving rise to the harmonic regime. Decreasing n further, we observe the turbulent-like regime. In this regime, the vortical structures are torn off near the tips of the vortices and small-scale structures are vigorously generated, constituting more violent behavior than in the harmonic regime. If the local Reynolds number near the wall and near the cores of the vortical structures reaches a critical value, the flow structure becomes turbulent-like after the bifurcation of the T-shaped branch. In addition, the modal characteristics of the vortical structures are analyzed using dynamic mode decomposition with respect to the degree of shear-thinning. As shear-thinning appears in the flow, various high-frequency modes with small-scale vortical structures are observed, and their energies are evenly distributed. This supports the present observation of the vortical structures depending on shear-thinning and -thickening.
Evaluation of redox potentials of cathode materials of alkali-ion batteries using extended DFT+U+U↑↓ method: The role of interactions between the electrons with opposite spins
Authors: Shishkin M. , Sato H.
Published: March 2021

Limitations of the DFT+U approach (e.g., in Dudarev’s formulation) applied for accurate evaluation of redox potentials of cathode materials of alkali-ion batteries with U parameters calculated via the linear response (LR) method are discussed. In contrast to our previous studies, where redox potentials of several cathode materials have been calculated in a good agreement with experiment (e.g., NaMnO2, LiFePO4, and LiTiS2), herein, we analyze other cathode materials, such as LiNiO2 and Ni- and V-containing phosphates for which this method provides much underestimated redox voltages. We ascribe this limited predictive power of the DFT+U method, parameterized via LR, to the absence of corrections of Coulomb interactions between the electrons with opposite spins. Using the recently proposed extended DFT+U+U↑↓ functional, which includes the aforementioned corrections, we show how redox potentials of Ni- and V-based compounds could be calculated in a much better agreement with experiment, also proposing a procedure of parameterization of such calculations. Thus, our extended method allows us to calculate redox potentials of several important materials more accurately while retaining good agreement with experiment for structures where the standard DFT+U method also accurately predicts electrochemical properties.
Magnetic tweezers with magnetic flux density feedback control
Authors: Moghram Waddah I. , Kruger Anton , Sander Edward A. , Selby John C.
Published: March 2021

In this work, we present a single-pole magnetic tweezers (MT) device designed for integration with substrate deformation tracking microscopy and/or traction force microscopy experiments intended to explore extracellular matrix rheology and human epidermal keratinocyte mechanobiology. Assembled from commercially available off-the-shelf electronics hardware and software, the MT device is amenable to replication in the basic biology laboratory. In contrast to conventional solenoid current-controlled MT devices, operation of this instrument is based on real-time feedback control of the magnetic flux density emanating from the blunt end of the needle core using a cascade control scheme and a digital proportional–integral–derivative (PID) controller. Algorithms that compensate for a spatially non-uniform remnant magnetization of the needle core that develops during actuation are implemented into the feedback control scheme. Through optimization of PID gain scheduling, the MT device exhibits magnetization and demagnetization response times of less than 100 ms without overshoot over a wide range of magnetic flux density setpoints. Compared to current-based control, magnetic flux density-based control allows for more accurate and precise magnetic actuation forces by compensating for temperature increases within the needle core due to heat generated by the applied solenoid currents. Near field calibrations validate the ability of the MT device to actuate 4.5 μm-diameter superparamagnetic beads with forces up to 25 nN with maximum relative uncertainties of ±30% for beads positioned between 2.5 and 40 µm from the needle tip.
A high-fidelity body-force modeling approach for plasma-based flow control simulations
Authors: Chen Di , Asada Kengo , Sekimoto Satoshi , Fujii Kozo , Nishida Hiroyuki
Published: March 2021

The well-known “ion wind” induced by a dielectric barrier discharge plasma actuator (DBD-PA) has been extensively used as an active flow control device in the boundary layer. Developing an accurate and efficient model for plasma-induced body force becomes the linchpin of the computational studies of DBD-PA-based flow control; both phenomenological and first-principle approaches have been largely investigated in the literature. In this research, a charged-particle model named Drift-Diffusion (D-D) model is employed to compute the body-force fields with ultra-high temporal resolution in a range of alternating voltage (peak-to-peak) from 7 kV to 20 kV. The analytical Suzen–Huang (S–H) model as an economical approach is also applied for comparison. Large-eddy simulations are employed to investigate the relationship between the DBD-PA-induced flow in quiescent air and the DBD-PA-controlled flow field over a stalled airfoil. The significance of body-force unsteadiness is well understood in the two flow fields by the model comparison. The results based on D-D model show good agreement with the corresponding experiments in both quiescent and separated flow fields, where the induced flow structure and separation control effect are carefully checked, respectively. As to the S–H model, the almost same magnitude but different location of the maximum wall-parallel induced velocity results in the stronger induced flow in quiescent field; however, the similar control effects in the separated flow. The present research provides a new approach to study the effect of DBD-PA-induced flow on separation control using the high-fidelity body-force field directly without any parametric calibration.
Ultrafast Ising Machines using spin torque nano-oscillators
Authors: Albertsson Dagur Ingi , Zahedinejad Mohammad , Houshang Afshin , Khymyn Roman , Åkerman Johan , Rusu Ana
Published: March 2021

Combinatorial optimization problems are known for being particularly hard to solve on traditional von Neumann architectures. This has led to the development of Ising Machines (IMs) based on quantum annealers and optical and electronic oscillators, demonstrating speed-ups compared to central processing unit (CPU) and graphics processing unit (GPU) algorithms. Spin torque nano-oscillators (STNOs) have shown GHz operating frequency, nanoscale size, and nanosecond turn-on time, which would allow their use in ultrafast oscillator-based IMs. Here, we show using numerical simulations based on STNO auto-oscillator theory that STNOs exhibit fundamental characteristics needed to realize IMs, including in-phase/out-of-phase synchronization and second harmonic injection locking phase binarization. Furthermore, we demonstrate numerically that large STNO network IMs can solve Max-Cut problems on nanosecond timescales.
Measurement of the optical constants of monolayer MoS2 via the photonic spin Hall effect
Authors: Chen Shizhen , Zhou Xinxing , Ling Xiaohui , Shu Weixing , Luo Hailu , Wen Shuangchun
Published: March 2021

How to explore the physical effect and characterize physical parameters in atomic scale crystals is still a challenging issue in modern optics. We detect the photonic spin Hall effect in monolayer MoS2 to study the atomic light-matter interaction. Due to the sensitive dependence of the spin-Hall shifts on the optical constants of MoS2, we propose this fundamental effect as a metrological tool for the parameter characterization. Combined with the weak-value technique, the experimental results show that the complex refractive index can be extracted by treating the atomically thin MoS2 as a homogeneous slab with an effective thickness. However, modeling the thin crystal as a surface current can determine the optical conductivity with a high measurement resolution. We believe this fast and precise measurement of optical parameters can provide a reliable approach to investigate optical properties for transition metal dichalcogenides.
The new single crystal dispersion interferometer installed on KSTAR and its first measurement
Authors: Lee Dong-Geun , Lee K. C. , Juhn J.-W. , Lee Jae-seok , Ghim Y.-c.
Published: March 2021

Dispersion interferometers have been used to measure line integrated electron densities from many fusion devices. To optically suppress noise due to mechanical vibrations, a conventional dispersion interferometer typically uses two nonlinear crystals located before and after the plasma along the laser beam path. Due to the long beam path, it can be difficult to overlap the fundamental and second harmonic laser beams for a heterodyne dispersion interferometer and to focus the beams on the second nonlinear crystal located after the plasma, especially when the aperture of the nonlinear crystal is small, i.e., of the order of mm. To overcome such difficulties, a new concept of a heterodyne dispersion interferometer, a single crystal dispersion interferometer (SCDI), is developed and installed on KSTAR with the laser wavelength of 1064 nm. The concept and the optical setup of the KSTAR SCDI are discussed, as well as its first measurement during a shattered pellet injection that produces abrupt and large changes in the electron density. To demonstrate feasibility, the KSTAR SCDI measurements are also compared with those from the existing two-color interferometer.
Nonlinear waves in a quintic FitzHugh–Nagumo model with cross diffusion: Fronts, pulses, and wave trains
Authors: Zemskov Evgeny P. , Tsyganov Mikhail A. , Kassner Klaus , Horsthemke Werner
Published: March 2021

We study a tristable piecewise-linear reaction–diffusion system, which approximates a quintic FitzHugh–Nagumo model, with linear cross-diffusion terms of opposite signs. Basic nonlinear waves with oscillatory tails, namely, fronts, pulses, and wave trains, are described. The analytical construction of these waves is based on the results for the bistable case [Zemskov et al., Phys. Rev. E 77, 036219 (2008) and Phys. Rev. E 95, 012203 (2017) for fronts and for pulses and wave trains, respectively]. In addition, these constructions allow us to describe novel waves that are specific to the tristable system. Most interesting is the pulse solution with a zigzag-shaped profile, the bright–dark pulse, in analogy with optical solitons of similar shapes. Numerical simulations indicate that this wave can be stable in the system with asymmetric thresholds; there are no stable bright–dark pulses when the thresholds are symmetric. In the latter case, the pulse splits up into a tristable front and a bistable one that propagate with different speeds. This phenomenon is related to a specific feature of the wave behavior in the tristable system, the multiwave regime of propagation, i.e., the coexistence of several waves with different profile shapes and propagation speeds at the same values of the model parameters.
Prevalence of Mental Health Problems in Men and Women in an Australian Prison Sample: Comparing Psychiatric History Taking and Symptom Screening Approaches
Authors: Korobanova Daria , Spencer Sarah-Jane , Dean Kimberlie
Published: March 2021

In an Australian survey of male and female adult prisoners ( N = 1,132), two approaches to identifying mental health problems (symptom screening and self-reported psychiatric history) were compared. A higher proportion of women (77.7%) than men (61.8%) reported a prior diagnosis of at least one disorder. Almost half (49.8%) screened positive for current symptoms of mental illness. The proportion of symptom screen-positive individuals missed by psychiatric history ranged from 15.5% to 81.6%. To identify all potential mental health need and fully inform service development, future studies should consider a range of approaches to case ascertainment, although validation of new approaches is required.
Plasma ammonia synthesis over mesoporous silica SBA-15
Authors: Gorky Fnu , Guthrie Shelby R , Smoljan Courtney S , Crawford James M , Carreon Moises A , Carreon Maria L
Published: March 2021

Herein we demonstrate the synthesis of ammonia via atmospheric dielectric barrier discharge plasma discharge over silica. We evaluated the performance of three structural different silicas: non-porous silica, fumed-silica and mesoporous SBA-15 silica. The mesoporous SBA-15 sample resulted in an ammonia synthesis rate per gram of catalyst at least three times higher than that of the non-porous and fumed silica when employing a hydrogen rich gas feed. The hierarchical ordered pore size in the mesoporous range of SBA-15 allowed us to observe experimentally, the pore size effect in the plasma discharge. Specifically, the ammonia production is enhanced by the presence of mesopores that can effectively enable the discharge diffusion into the pore as predicted by theoretical calculations. The importance of the porous structure was confirmed by optical emission spectra which indicates a similarity on the relative intensity on the main plasma activated species in the gas phase such as N2
+, NH and

H
α

for the three silicas employed in this work i.e. non-porous, fumed and mesoporous (SBA-15). However, the remarkable ammonia production when employing the SBA-15 shows that despite the similarities in the gas phase the main differences might be attributed to the diffusion of the plasma discharge into the pores.
VS2 nanosheet as a promising candidate of recycle and reuse NO2 gas sensor and capturer: a DFT study
Authors: Zhao Rumeng , Wang Tianxing , An Yipeng , Dai Xianqi , Xia Congxin
Published: March 2021

We describe the utilization of VS2 nanosheet as high sensing response, reuse, and thermodynamic stability at room temperature NO2 and NO gas sensors by using the density functional theory method. We focus on the electronic structures and adsorption energy toward a variety of gaseous molecules (such as O2, CO, H2O, NH3, NO, and NO2) adsorbed on the VS2 nanosheet. The results show that chemical interactions existed between NO/NO2 molecules and VS2 nanosheet due to sizable adsorption energy and strong covalent (S–N) bonds. In particular, the adsorption energies, charge transfer and electronic properties between NO2 adsorbed system is significantly changed compared with the other gas molecules (CO, NO, H2O, NH3, and O2) adsorbed systems under biaxial strains, which is effective to achieve the capture or reversible release of NO2 for cycling capability. Our analysis indicates that VS2 nanosheet is promising as electrical devices candidate for NO2 high-performance gas sensor or capturer.
Analytic description of spin waves in dipolar/octupolar pyrochlore magnets
Authors: Assi I A , Curnoe S H
Published: March 2021

We derive analytic forms for spin waves in pyrochlore magnets with dipolar-octupolar interactions, such as Nd2Zr2O7. We obtain full knowledge of the diagonalized magnonic Hamiltonian within the linear spin wave approximation. We also consider the effect of a ‘breathing mode’ as a perturbation of this system. The breathing mode lifts the degeneracy of the upper band of the spin wave dispersion along the direction X → W in k-space.
Probing hole spin transport of disorder quantum dots via Pauli spin-blockade in standard silicon transistors
Authors: Hillier Joseph , Ono Keiji , Ibukuro Kouta , Liu Fayong , Li Zuo , Husain Khaled Muhammad , Nicholas Rutt Harvey , Tomita Isao , Tsuchiya Yoshishige , Ishibashi Koji , Saito Shinichi
Published: March 2021

Single hole transport and spin detection is achievable in standard p-type silicon transistors owing to the strong orbital quantization of disorder based quantum dots. Through the use of the well acting as a pseudo-gate, we discover the formation of a double-quantum dot system exhibiting Pauli spin-blockade and investigate the magnetic field dependence of the leakage current. This enables attributes that are key to hole spin state control to be determined, where we calculate a tunnel coupling t

c
of 57 μeV and a short spin−orbit length l
SO of 250 nm. The demonstrated strong spin−orbit interaction at the interface when using disorder based quantum dots supports electric-field mediated control. These results provide further motivation that a readily scalable platform such as industry standard silicon technology can be used to investigate interactions which are useful for quantum information processing.
Adapting a solar photovoltaic panel experiment for blind students
Authors: Hahn Marcelo , Cruz Frederico , Carvalho P Simeão , Ferreira Vanessa , Marques Filipe , Macieira Cláudio
Published: March 2021

Renewable energy is a trending topic due to its importance in today’s society especially because of global warming. Because of its importance, this topic should be discussed at schools in an inclusive education environment. Experimental work is a very good activity to provide students effective conceptual discussions, but it is necessary to improve the teaching–learning process for an inclusive education paradigm. In this paper we propose a low-cost experimental activity using Arduino that allows regular students and blind students to explore together and understand features and properties about solar energy and a photovoltaic panel, such as how the electric power generated by the photocell depends on the angle of incidence of solar light and the load resistance of the circuit.
A cost-effective quantum eraser demonstration
Authors: Khandelwal Aarushi , Tan Jit Bin Joseph , Leong Tze Kwang , Yang Yarong , Venkatesan T , Jani Hariom
Published: March 2021

The quantum eraser is a variation of the celebrated Young’s interference experiment that can be used to demonstrate the elusive complementarity principle in quantum physics. Here we show the construction of its classical analogue for deployment in classrooms in a simple, cost-effective yet robust manner by employing a laser pointer, double-slits, and polarizers.
Continuous variable multimode quantum states via symmetric group velocity matching
Authors: Roman-Rodriguez V , Brecht B , K Srinivasan , Silberhorn C , Treps N , Diamanti E , Parigi V
Published: March 2021

Configurable and scalable continuous variable (CV) quantum networks for measurement-based quantum information protocols or multipartite quantum communication schemes can be obtained via parametric down conversion (PDC) in non-linear waveguides. In this work, we exploit symmetric group velocity matching (SGVM) to engineer the properties of the squeezed modes of the PDC. We identify type II PDC in a single waveguide as the best suited process, since multiple modes with non-negligible amount of squeezing can be obtained. We explore, for the first time, the waveguide dimensions, usually only set to ensure single-mode guiding, as an additional design parameter ensuring indistinguishability of the signal and idler fields. We investigate here potassium titanyl phosphate (KTP), which offers SGVM at telecommunications wavelengths, but our approach can be applied to any non-linear material and pump wavelength. This work paves the way toward the engineering of future large-scale quantum networks in the CV regime.
Smith–Purcell radiation of a vortex electron
Authors: Pupasov-Maksimov A , Karlovets D
Published: March 2021

A wide variety of emission processes by electron wave packets with an orbital angular momentum ℓℏ, called the vortex electrons, can be influenced by a nonparaxial contribution due to their intrinsic electric quadrupole moment. We study Smith–Purcell radiation from a conducting grating generated by a vortex electron, described as a generalized Laguerre–Gaussian packet, which has an intrinsic magnetic dipole moment and an electric quadrupole moment. By using a multipole expansion of the electromagnetic field of such an electron, we employ a generalized surface-current method, applicable for a wide range of parameters. The radiated energy contains contributions from the charge, from the magnetic moment, and from the electric quadrupole moment, as well as from their interference. The quadrupole contribution grows as the packet spreads while propagating, and it is enhanced for large ℓ. In contrast to the linear growth of the radiation intensity from the charge with a number of strips N, the quadrupole contribution reveals an N
3 dependence, which puts a limit on the maximal grating length for which the radiation losses stay small. We study spectral-angular distributions of the Smith–Purcell radiation both analytically and numerically and demonstrate that the electron’s vorticity can give rise to detectable effects for non-relativistic and moderately relativistic electrons. On a practical side, preparing the incoming electron’s state in a form of a non-Gaussian packet with a quadrupole moment—such as the vortex electron, an Airy beam, a Schrödinger cat state, and so on—one can achieve quantum enhancement of the radiation power compared to the classical linear regime. Such an enhancement would be a hallmark of a previously unexplored quantum regime of radiation, in which non-Gaussianity of the packet influences the radiation properties much stronger than the quantum recoil.
Recurrence relations in m × 3 scaffolding and globe resistor networks
Authors: Perrier Frédéric , Girault Frédéric
Published: March 2021

Resistor networks are popular because they offer solvable models of transport between connected discrete points and can represent natural or artificial systems such as mycorhizzal networks or carbon composite chains. When the connectivity pattern is repeated, two-point resistances can be expressed by recurrence relations. Here, we illustrate this approach in the case of three-dimensional m × 3 scaffolding and globe networks, characterized by a repeated pattern along a three-fold invariant axis. We show that a first set of recurrence relations follows from three-fold invariance and Kennelly’s Y-Δ transform, providing the two-point resistance between any pair of neighbouring nodes, including the case of infinite networks. Using van Steenwijk’s method, a second set of recurrence relations is obtained between non-neighbouring nodes. Numerous explicit expressions are thus derived using elementary methods, which can be compared with the results of numerical codes or novel integration methods such as Tan’s recursion-transform. Having at hand general properties of these networks is useful to evaluate their capacity of representing natural or industrial systems.
A new way of measuring the correlation length in surface growth models
Authors: Kim Jin Min
Published: March 2021

We propose a new way of measuring the correlation length in surface growth processes. We define a quantity

R

(

L
,
t

)

=

⟨

w

4

(

L
,
t

)

⟩

⟨

w

2

(

L
,
t

)

⟩

2

−
1

L

in d = 1 + 1, where w(t) and L are the surface width of a given sample at time t and the system size, respectively, and ⟨…⟩ denotes the average over samples. The quantity R(L, t) is proportional to the correlation length and follows the relation R(L, t) ∼ t
1/z
before the saturation for various growth models, where z is the dynamic exponent. The applicability of the method was examined for the restricted solid-on-solid (RSOS) model, equilibrium solid-on-solid model, and restricted curvature model. We also estimated z by using the relation R(t) ∼ t
1/z
for the RSOS model in higher dimensions.
The inhibition of mild steel corrosion in 0.5 M H2SO4solution by N-phenethylhydrazinecarbothioamide (N-PHC)
Authors: Shaker Lina M. , Al-Adili Aqeel , Al-Amiery Ahmed A. , Takriff Mohd S.
Published: March 2021

A new corrosion inhibitor namely N-phenethylhydrazinecarbothioamide (N-PHC) was synthesized through the reaction of hydrazine hydrate and (2-isothiocyanatoethyl)benzene. N-PHC has been characterized by spectroscopically techniques and CHN micro-elemental analysis. The inhibitive activity of N-PHC on mild steel corrosion in 0.5 M sulphuric acid solution was examined by the weight loss techniques. The findings exhibited that the inhibition efficiency increased with an increase in the concentration of N-PHC and decreased with an increase in temperature. The inhibition efficiency reached 94.7% with 250 ppm at 303 K. The inhibitive mechanism involved chemical adsorption and the adsorption of the N-PHC molecules through active sites on the surface of mild steel to control or retard corrosion. The adsorption isotherm obeyed the Langmuir isotherm.
Synthesis of Ag/Au (core/shell) nanoparticles by laser ablation in liquid and study of their toxicity on blood human components
Authors: Abed Mayada A. , Mutlak Falah A-H. , Ahmed Ala F. , Nayef Uday M. , Abdulridha Sarah K. , Jabir Majid S.
Published: March 2021

Q-switch Nd: YAG laser of wavelengths 235nm and 1,460nm with energy in the range 0.2 J to 1J and 1Hz repetition rate was employed to synthesis Ag/Au (core/shell) nanoparticles (NPs) using pulse laser ablation in water. In this synthesis, initially the silver nano-colloid prepared via ablation target, this ablation related to Au target at various energies to creat Ag/Au NPs. Surface Plasmon Resonance (SPR), surface morphology and average particle size identified employing: UV-visible spectrophotometer, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The absorbance spectra of Ag NPs and Ag/Au NPs showed sharp and single peaks around 400nm and 410nm, respectively. The average diameter achieved for Ag/Au NPs were as 30nm and 25nm corresponding to 532nm and 1064nm, respectively. The TEM images showed that Ag/Au NPs possess a spherical shape, while the samples average size were in range from 20 to 30nm. There was an obvious increase in size during the use of 532nm laser. As for the effects of toxicity, results on human blood components showed that these nanoparticles have no effect on RBCs, WBCs and HB Therefore; these particles considered promising in the biological and medical applications.
Energy Band Diagram of FTO/porous Silicon Heterostructure
Authors: Hadi Hasan A. , Ismail Raid A.
Published: March 2021

We have proposed for the first time the energy band diagram of fluorine doped tin oxide FTO/porous silicon PSi/n-Si heterostructure prepared by spray pyrolysis technique and laser assist-electrochemical etching ECE. The band line-up of the heterojunction was constructed from the electrical and optical properties of FTO and porous silicon. The electrical current-voltage and capacitance-voltage measurements showed the barrier height, ideality factor and built in voltage of the heterojunction were 1.4, 0.69 V and 0.70 V, respectively. The optical energy gap and the average of the optical transmittance of FTO film were 3.6 eV and 78% respectively. The morphology of porous silicon PSi and FTO film investigated by scanning electron microscope SEM. The elemental composition of FTO film was determined using energy dispersive x-ray.
Laser assisted hydrothermal synthesis of magnetic ferrite nanoparticles for biomedical applications
Authors: Aswad Mohanad A. , Mutlak Falah A-H. , Jabir Majed S. , Abdulridha Sarah K. , Ahmed Ala F. , Nayef Uday M.
Published: March 2021

In this work, copper substituted cobalt ferrite nanoparticles Co1-xCuxFe2O4 (×=0, 0.3, and 0.7), has been synthesized via laser assisted hydrothermal synthesis (LAHS) methods. The XRD patterns showed single phase spinel structure, comparative study between the two preparation methods, effect of laser irradiation on the structural properties, and average crystallite size that is evaluated from most intense peak (311) utilizing Scherrer formula. Further studies for laser assisted hydrothermal as-prepared ferrite samples using each of Field emission-scanning electron microscope (FE-SEM) which revealed the study of topography, shape, particle size, vibrating sample magnetometer (VSM) with in 15kOe as maximum field. That was used to study the magnetic properties and confirmed the super-paramagnetic property of the prepared ferrite nanoparticles. Coercivity (Hc), remanence (Mr), saturation magnetization (Ms) and sequarness ratio were directly extracted from hysteresis loops. Moreover, results showed that the magnetic characteristics are on the basis of each particle size as well as cation distribution. In addition, the antibacterial property of the prepared nanoparticles against S. aureus and E. coli found to be improved after substitution of Cu in Co ferrite matrix.
Influence of Heat Treatment on the Characteristic of SnO2 Thin Films for Gas Sensor Application
Authors: Jasim Ammar M. , Al-Zubaydi Ahmed S.J. , Zamel Rafid S.
Published: March 2021

Nano-crystalline SnO2 films were deposited on glass substrates using dip coating by sol–gel technique for gas sensor applications. These films have been annealed in air at 300, 350 400, and 450 °C for 60 min, and at 400 °C for 15, 30 min. The films have been analyzed through x-ray diffraction and optical absorption spectroscopy. The deposited films have shown tetragonal rutile structures. The average crystallite size increased as annealing temperature increased. The crystallite sizes of the annealed films were 8 nm at 300 °C, 10 nm at 350 °C, 14 nm at 400 °C, and 22 nm at 450 °C for 60 min. Whereas the crystallite sizes showed 16 and 15 nm at annealing temperature of 400 °C for 15 and 30 min, respectively. The energetic values of optical band gaps of the films showed increment with the elevation in annealing temperatures. The optical band gap energies were 2.86, 2.86, 3.14 and 3.35 eV at annealing temperatures of 300, 350, 400, and 450 °C, for 60 min, respectively, and 3.43 and 3.35 eV at annealing temperature of 400 °C for 15 and 30 min, respectively. Electrical D.C. conductivity were measured at temperatures ranging from 30 °C to 170 °C, and these measurements showed an exponential increment as the temperature and time increased. The films were studied in the matter of sensing capabilities for CO gas through evaluation at various times and temperatures. The optimum sensitivity was found at annealing temperature 400 °C. The outcomes revealed a high sensitivity of the deposited films for carbon monoxide at operation temperature of 200 °C.
Effect of Mn-substitution on the structure Co0.6Zn0.4Fe2O4
Authors: Hasan N. , Hadi Mohammed H.
Published: March 2021

One Ferrite is a ferromagnetic substance where it is ideally used to manufacture devices such as rectifiers, memory devices, and inductors hearts as well as for various applications of microwave waves. The electrical and structural characterization of ferrites depends on preparation methods, nature of dopant, and dopant concentration. For these reasons, the series samples of Co0.6Zn0.4MnxFe2−xO4 ferrites prepared, using a traditional ceramic process, Mn-Zn ferrites were synthesized and sintered up to 1200 °C for 5 hours. We tested the X Ray diffraction (XRD) for different Mn-substitution (where x = 0, 0.2, and 0.4). XRD studies confirmed that the sample’s structural have a cubic spinel phase. The electrical characterization (such as conductivity, real and imaginary dielectric constant) was measured and discussed, as well.
Mechanical and Physical Properties of PMMA Reinforced HA-MgO Nano-Composite
Authors: Mansour Ali Abd A. , Al-Ramadhan Zainab A. , Abdulrazaq Raghad A.
Published: March 2021

In this paper, a combination of a ceramic mixture with a polymer was developed to be used as a substitute for damaged bones or teeth. Overlays were prepared using the manual mixing method, followed by the use of ultrasound technology to ensure uniform distribution of the powder within the polymer. The polymer (PMMA) is supported with a ceramic powder (HAMgO) prepared using an effective mechanical mixing method and component than hydroxyapatite (HA) is a principle inorganic component of human hard tissues such as teeth and bones and metal nanoparticle magnesium oxide (MgO), which represents the additive to the polymer (PMMA). The percentage used for reinforcement, starting from (1% - 4%). The results of the tests showed mechanical corrosion or the so-called where wear is decreased for the reinforced polymeric composites as the corrosion rate decreased to less than half at 4%. Likewise, the results of the particle hardness examination showed a successive increase in the percentages compared to the polymer base material. The results of the durability of compressibility and Young’s modulus showed a direct increase with the increase in the percentages of the added ceramic powder.
Study of optical and morphological properties for Au-ZnO nanocomposite prepared by Laser ablation in liquid
Authors: Rashid Taha M. , Nayef Uday M. , Jabir Majid S. , Mutlak Falah A-H.
Published: March 2021

The preparation of Au-ZnO nanocomposite involves the synthesis of Au and ZnO colloidal solutions by Nd:YAG laser (1064nm) ablation of metal targets in deionized water followed by laser irradiation of the mixed colloidal solution by a second harmonic Nd:YAG laser (532nm).

The UV-visible show the gold nanoparticle (NPs) peak at 525nm while the peak of the ZnO nanoparticle (NPs) at 375nm. The Au-ZnO nanocomposite showed a blue shift in the absorption of the ZnO excited, while due to the plasomon resonance and interfacial charge transfer of Au NPs lead to redshift in the absorption, also show the intensity absorpation increases with the concentration of the metal nanoparticles. The morphological properties of nanoparticles have been characterized by Transmission Electron Microscopy (TEM).
Study the Structural, Morphological and Optical Properties of Copper Sulfide Prepared by Two-Phase Colloidal Method
Authors: Al-Jawad Selma M H. , Taha Ali A , Muhsen Mustafa M
Published: March 2021

In this paper, copper sulfide nanoparticles were synthesized by two-phase colloidal method with different reaction temperatures (140, 160, 180 and 200°C). The structural, morphological and optical properties of prepared CuS were analyzed by the X-Ray Diffractometer (XRD), Field Emission Scanning Electron Microscope (FESEM) and UV-VIS Spectrophotometer. The XRD peaks refer to the covellite copper sulfide with hexagonal structure. FESEM showed the rod formation at lower temperatures (140 and 160°C), whereas higher temperatures (180 and 200°C) form nanocrystals within spheres structures. UV-VIS showed that CuS nanoparticles have two absorption peaks, one at UV-VIS region and the second at NIR region and its energy gap decrease with increasing of reaction temperature.
An investigation of the Structural, Electrical and Optical Properties of Graphene-Oxide Thin Films Using Different Solvents
Authors: Rasheed M. , Shihab S. , Sabah O. Wissam
Published: March 2021

Graphene oxide (GO) thin films were prepared successfully using modified Hummer’s method, which includes oxidation of graphite and reduction to graphene oxide at room temperature. Then; the samples were deposited on glass substrates using the sol-gel technique. Different solutions have been used to obtain graphene oxide such as Ethanol, Acetone, and Deionized Water. The structural, optical and electrical properties of the prepared samples were diagnosed and studied using optical microscope and XRD diffraction, Fourier Transform Infrared Spectroscopy (FTIR) and UV-Vis spectrophotometer respectively. XRD pattern confirmed the formation of graphene oxide with a sharp peak at an angle of 2θ=11.42°. Thicknesses of (GO) samples using weight method have been calculated. In addition, the optical properties of the samples such as transmittance, reflectance, refractive index, extinction coefficient, and optical energy gap have been measured. The optical band gap of the samples dissolved in acetone, deionized water and ethanol has been measured of about 2.5, 2.45 and 2.35 eV respectively.
CO2 Laser Micro-Engraving of PMMA Complemented By Taguchi and ANOVA Methods
Authors: Imran Hadeel J , Hubeatir Kadhim A , Al-Khafaji Mohanned M
Published: March 2021

Laser micromachining is used in the microfluidic application, especially in biomedical technology, the point of care diagnostics, and chemical analysis. In this research work, a micro-engraving was done on PMMA (Polymethylmethacrylate) using a CO2 laser. Based on the Taguchi design of the experiment; 25 experiments were done to study the effect of laser parameters on the micro-engraving process. The effect of input parameters, laser power, engraving speed, and overlapping space has discussed on the micro-engraving characteristic, surface roughness, engraving depth, and overall time of the process. The results show different surface roughness ranged between 7 – 1.72 µm. Also, the depth results ranged between 20.4 – 5800 µm which could be used in many various applications. The ANOVA results showed that the engraving speed has a significant”effect on surface roughness and”engraving depth, but in engraving time, the laser power has a substantial impact at 94.06%.
Comparison between Inductively Coupled Plasma-Mass Spectrometer (ICP-MS) and X-Ray Fluorescence (XRF) Spectrometer in elemental Analyses Iraqi Table Salt
Authors: Kareem Alghurabi Milad Nazar Abdul , Yıldırım Sema Öztürk
Published: March 2021

Salt is commonly used substance in our daily life. For good general health some simple chemical substances are added to table salt during manufacturing as iodide and iodide stabilizers mostly potassium iodide. In this study, ten different samples of table salts from different factories in Iraq were analyzed by two different analytical methods. As the results of salt samples by ICP-MS analysis are magnesium (Mg), aluminum (Al), potassium (K), calcium (Ca), manganese (Mn), iron (Fe), nickel (Ni), zinc (Zn), strontium (Sr), barium (Ba). On the other hand the elements in salt samples by XRF analysis are chlorine (Cl), sodium (Na), calcium (Ca), sulfur (S), magnesium (Mg), silicon (Si), potassium (K), aluminum (Al), iron (Fe), rhodium (Rh), ruthenium (Ru), bromine (Br), strontium (Sr), gallium (Ga), phosphorus (P), nickel (Ni).
A prototype of IoT-based smart system to support motorcyclists safety
Authors: Prasetyawan P , Samsugi S , Mulyanto A , Iqbal M , Prabowo R , Ardiansyah
Published: March 2021

This study described the prototype of the smart system for support safety riding using the Internet of Things (IoT) technology. This system consists of connectivity objects like helmets, motorcycles, and riders/people (via smartphone). The system is pervasive in helmets and motorcycle with several main electronic components, including NodeMCU micro controller, accelerometer-gyroscope sensor, a GPS (Global Positioning System) module, flex sensor, buzzer, and relay. The helmet, motorcycles, and riders then are connected with others through the internet with the android application interface. The application can monitor real-time status and location riders using firebases’s real-time database. This system has four features, which are a combination of previous related works, namely helmet detection, drowsiness detection, accident detection, and notification with the accident’s location that can be tracked by others. The results of this system prototype experiment showed that all features of the system are running well. The accuracy value for helmet detection is 100%, drowsiness detection is 87%, and accident detection is 90%. Rider status and location can be monitored and tracked by others via the android application.
Comparative analysis of naïve bayes and knn on prediction of forex price movements for gbp/usd currency at time frame daily
Authors: Pande K S Y , Divayana D G H , Indrawan G
Published: March 2021

This study aims to analyze the comparison of the Naïve Bayes and kNN on the Prediction of Forex Price Movements for GBP / USD on Time Frame Daily. The data used is taken from the metatrader-4 application which is often used by forex traders when making transactions. There are 2,145 data rows consisting of the date, hour, open price, high, low, close, and transaction volume columns. From this data, a column for the target class is created with the name ‘result’. The result column is filled with increasing or decreasing values. The value of increase or decrease is obtained from the comparison of the previous closing price with the closing price of the next day. This study analyzes the results of the comparison of the data mining classification of algorithm between the Naïve Bayes algorithm and kNN. The 2,145 data were divided into 2 parts, namely 80% for training data and 20% for testing data. The analysis is done by comparing the precision, recall, and accuracy test results for each algorithm. The conclusion of this study is that the kNN algorithm is better than the Naïve Bayes algorithm in case of predicting forex price movements for GBP/USD currency at time frame daily.
Designing an interoperable social assistance health insurance validation system
Authors: Seputra K A , Aryanto K Y E
Published: March 2021

Many social assistance programs must be managed by local governments, including health insurance contribution assistance (PBI). The government must be able to distribute social assistance recipients equally and accurately. The government must ensure that only one family member is registered in one of the social assistance schemes, such as PKH (Program Keluarga Harapan), PBI (Program Bantuan Iuran), or BLT (Bantuan Langsung Tunai). Therefore, interoperability of data between systems is important to check and validate the membership of potential participants in one assistance scheme. Valid data is the key in data exchange, especially PBI data that has not been processed optimally. However, there are still inconsistent and incomplete data on the annual PBI participants. The first thing that can be done is to validate PBI data. Through the PBI data validation system, validation can be carried out more thoroughly by utilizing the supported data from the API of the civil registration and the Bridging BPJS. With the validation system, PBI data management becomes more accurate and has fast access to facilitate reporting compared to the previous system that still used Excel. The PBI validation system also supplies valid PBI data to related systems that have registered with the API services. By using JWT in RESTfull API, system interoperability could be done securely.