bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural and Luminescence Properties of Eu3+ and Dy3+ Doped Magnesium Tellurite Borophosphate Ceramic
Authors: Aziz Siti Maisarah , Hussin Rosli , Yusoff Nurulhuda Mohammad
Published: June 2015

Lately, researchers have been considering the miscellaneous in the borophosphate crystalline’s luminescence as one of the important properties in hunt of the new functional material. In this study we discus the structural and luminescence properties of Eu3+/Dy3+ co-doped borophosphate ceramic. A series of ceramic samples based on B2O3-(65-)P2O5-25MgO-10TeO2 where (065) mol has successfully been prepared using solid state reaction method and sintered at 900°C. The crystalline phase of the powder samples was characterized using X-ray diffraction pattern. The diffraction patterns analysis indicated that the prepared samples were polycrystalline phase of B(PO4), Mg(PO3)2and Mg(BO3)(PO4). The local structure network structure has been investigated using Infrared Spectroscopy using KBr method. The FT-Infrared spectra reveal the presence of B-O-B vibrations, BO3 and BO4 bridging oxygen and P-O stretching modes of P-O-P, P=O and PO4 unit in the ceramics sample. Meanwhile, the luminescence properties of doped sample were measured based on analysis of emission spectra of photoluminescence spectroscopy. The emission peaks of Eu3+ doped sample were located at 593 nm, 613 nm, 652 nm, 685 nm due to the assigned transition 5D0-7FJ( J = 1, 2, 3, 4 ). The Dy3+ emission is due to 4F9/2 -5H15/2 and 4F9/2-6H13/2 transition. For Eu3+/Dy3+ co-doped sample consists of peaks belonging to the 4F9/2-6H15/2 (482 nm) and 4F9/2-6H13/2 (573 nm) transition while red emission 5D0-7F2 transitions appears at 611 nm. Improvement in the optical properties due to co-doping may be useful to discover a new highly efficient luminescent material that are very useful in optical devices and solid-state lighting.
Synthesis of Graphene via Green Reduction of Graphene Oxide with Simple Sugars
Authors: Kamisan Ainnur Izzati , Kamisan Ainnur Sherene , Md Ali Ruslinda , Tunku Kudin Tunku Ishak , Hassan Oskar Hasdinor , Abdul Halim Norhana , Yahya Mohamad Faizul
Published: June 2015

A new carbon material called graphene has been attracting an increasing research interest owing to its unique electrical and mechanical properties that is useful for the various device applications. The synthesis of graphene from graphene oxide usually involves harmful chemical reducing agents that are toxic and undesirable to human and the environment. By avoiding the use of toxic and environmentally harmful reductants, we report a green approach for the reduction of graphene oxide by using reducing sugars to synthesis graphene. Graphite oxide was synthesized from graphite powder using modified Hummers method. Graphite oxide then further exfoliated to graphene oxide by using ultrasonic irradiation. Graphene then was obtained by the mild reduction of graphene oxide with reducing sugars (glucose, lactose and maltose). The structural study of the as-prepared graphene is characterized by Raman spectroscopy and fourier infra red spectroscopy. Raman and FTIR spectra indicates the partial removal of oxygen functional groups from the surface of GO. Characterizations indicate that graphene oxide is successfully reduced to graphene by sugar.
Effect of CdS Thickness on the Optical and Structural Properties of TiO2/CdS Nanocomposite Film
Authors: Mohsin Ali Kamel , Bidin Noriah
Published: June 2015

Efficient modification of energy band gap to absorb visible light in TiO2 semiconductor nanocomposites is challenging. The effect of the varying CdS thickness (50-100 nm) on the structural and optical properties of TiO2/CdS nanocomposite films (NCF) grown by electron beam deposition is reported. The surface morphology and optical behaviors are characterized via XRD, AFM and UV-Vis measurements. The lattice parameters and nanocrystallinity of TiO2/CdS NCF determined from XRD patterns are found to increase gradually with the increase of CdS thickness. The mean particles size estimated using Scherer formula and AFM micrographs lies in the range of 10.29 -59.71 nm for various CdS thickness. The increase in root mean square roughness with the increase of CdS thickness is revealed by AFM micrographs. The UV-Vis measurement shows a significant enhancement in the absorption of NCFs in the range of 340 to 500 nm due to the addition of a small portion of CdS. Interestingly, Our results suggest that the optical and structural properties of TiO2 films can significantly be improved and finely tuned by varying the thicknesses of CdS film useful for applications.
Luminescence Properties of Europium Ion Doped Barium Borophosphate Phosphor
Authors: Kamal Mukarramah M. , Yusuf M. Nor M. , Atiqah Jailani N. , Sholehah Hussein S. , Hussin R. , Deraman Karim , Shamsuri W. Nurulhuda W. , Ibrahim Zuhairi
Published: June 2015

A series of BaBPO5 phosphors doped with different concentration of Eu2+ ions were synthesized by solid state reaction method. The reduction of Eu3+ to Eu2+ ions were obtained by heating in pure argon atmosphere. The structural properties were analyzed by using X-ray diffraction (XRD). Luminescence properties were measured at room temperature using photoluminescence (PL) spectroscopy and the effects of europium ion in the phosphor were investigated. The XRD results showed that crystal structure of the phosphor is hexagonal single phases. The addition of europium ions exhibit a broad emission band in the violet region peaking at 383 nm corresponding to transition of configuration state 4f6 5d à 4f7 (8S7/2) of Eu2+ ions. The emission intensity is affected by the concentration of Eu2+. The optimum intensity is observed for 0.2 mol % of Eu2+ ion. The occurrence of emission lines in violet region indicates that this phosphor has potential in solid-state lighting application.
Impedance Spectroscopy in Ni0.3Zn0.7Fe2O4
Authors: Mat Mohd Noor , Halimah Mohamed Kamari , Daud W.M. , Mansor H. , Zainuddin Y.
Published: June 2015

Abstract. Impedance spectroscopies were used to investigate the electrical properties of spinel Ni0.3Zn0.7Fe2O4 (NZF) ceramics. Measurement was done using NOVO Dielectric Spectrometer from frequency 0.01 Hz to 3 x 106 Hz at temperature 30°C to 200°C. Resistivity response phenomena had been observed in sample sintered at 1100°C and carriers involved are mainly due to electron hopping mechanism between n-type and p-type carriers. The high and low response of grain and grain boundary regions were determined by plotting imaginary part versus real part of resistivity. An equivalent RC circuit of the experimental result had been constructed using a model that had been proposed by Hill and Pickup (1985). The model consists of parallel combination of 2 Havriliak-Negami (1966) model, resistivity and dielectric constant where ρ = 5.79 x 106 Ωm and ε = 4.45. It is found that 0.40 ± 0.01 eV, 0.14 ± 0.01 eV and 0.13 ± 0.01 eV and 0.38 ± 0.01 eV (extrinsic region) and 0.50 ± 0.01 eV (intrinsic region) for ac and dc activation energy respectively by using Arrhenius plot.
In Situ Cadmium Suflide Synthesis in Polymer Thin Film for Solar Cells Application
Authors: Naning Fatin Hana , Malik S. , Ahmad Zanuldin
Published: June 2015

Cadmium sulfide (CdS) were synthesised directly in the active layer of solar cell by mixing regioregular poly (3-hexylthiophene-2,5-diyl) or P3HT with stearic acid, and exposed to hydrogen sulfide gas. The exposure times to hydrogen sulfide gas were varied and the isotherm of P3HT:Stearic acid obtained show that the presence of cadmium ions in the subphase changes the gas-liquid-solid transformation profile. UV-Vis-NIR results indicated that exposure to hydrogen sulfide gas created CdS particles resulting in wider absorption spectra. The exposed P3HT:SA active layer exhibit high resistance that affects short circuit current density and open circuit voltage of the solar cells device. Keywords: CdS, P3HT, Thin Film, Angle Lifting Deposition, Solar Cells
Biopolymer-Based Thin Film for Sensor Application
Authors: Fen Yap Wing , Mahmood Mat Yunus Wan , Talib Zainal Abdib , Yusof Nor Azah
Published: June 2015

Chitosan is one of the most available biopolymers in nature, which is non-toxic, biocompatible and biodegradable. The crosslinked chitosan solution was synthesized by homogeneous reaction of medium molecular weight chitosan in aqueous acetic acid with glutaraldehyde as crosslinking agent. Then the solution was deposited on glass cover slip by spin coater to form a thin film. The functional group and chemical binding of crosslinked chitosan thin film has been confirmed by X-ray photoelectron spectroscopy (XPS). The chemical interaction between copper ion and the crosslinked chitosan thin film has also been analyzed by XPS. XPS revealed that copper ion adsorbed to the crosslinked chitosan thin film and the functional groups involved in the adsorption mechanisms of copper ion on the thin film were determined. This biopolymer thin film can be incorporated with surface plasmon resonance technique to produce a high potential optical sensor for detection of Cu (II) ion in solution.
Structural Properties of Al2O3:C:Mg Thin Films by RF Magnetron Sputtering
Authors: Awang Ainun Jariah , Wagiran Husin , Ismail Abd Khamim
Published: June 2015

Carbon doped aluminum oxide co-doped with magnesium (Al2O3:C:Mg) thin films were deposited using radio frequency magnetron sputtering method on Si (100) substrates. The deposition chamber temperature was manipulated to allow control over the crystalline phase. The crystalline phase of deposited thin films were determined by x-ray diffraction (XRD) technique. Slight change in crystallite size was observed with respect to the increasing deposition chamber temperature. Fourier transform infrared (FTIR) analyses indicated a negligible interfacial SiO2 growth during deposition. Transmission spectra of FTIR showed the bond and functional group of deposited thin films.
Growth and Characterization of Aln Thin Film Deposited by Sol-Gel Spin Coating Techniques
Authors: Nurfahana Mohd Amin , Lee Zhi Yin , Fong Chee Yong , Shiong Ng Sha
Published: June 2015

This study signifies the growth and characterization of aluminium nitride (AlN) thin film deposited on the atmospheric plasma treated n-type silicon [n-Si (100)]. Basically, the low cost spin coating technique which emphasized the production of a thin and uniform film on a flat substrate through a dilute solution is adopted. For the precursor preparation, the main ingredient of aluminium nitrate hydrate is dissolved with an organic solvent. The nitridation process is carried out on the deposited coating at 1100 °C for 1 hour. The surface morphology and structural properties of the thin film were investigated by field-emission scanning electron microscope, atomic force microscopy energy, dispersive X-ray spectroscopy and X-ray diffraction; while the optical properties of the deposited thin film was determined by using Fourier transform infrared spectrometer. All the results revealed that AlN thin film was successfully deposited on n-Si (100) substrate.
Effect of Gamma Radiation on ZnO Doped PVA Nanocomposite Thin Films for Escherichia coli Sensor
Authors: Noor Azmy Noor Azwen , Abdullah Huda , Mohammad Naim Norshafadzila , Abdul Hamid Aidil , Shaari Sahbudin , Wan Mokhtar Wan Hanna Melini
Published: June 2015

The effect of gamma radiation on fabricated ZnO doped PVA nanocomposite thin films for determination of Escherichia coli has been investigated. Thin films of ZnO doped PVA were exposed to 60Co γ-radiation source at difference dose rate, ranging from 0 to 30 kGy at room temperature. The structural, morphological and electrical properties of the sample were investigated using X-ray diffraction (XRD), Atomic force microscopy (AFM) and Current-voltage (I-V) measurement. The X-ray diffraction (XRD) spectra have been performed to see the formation of crystal phases of all pure ZnO thin films. The diffraction patterns reveal the good crystalline quality and indicate the crystallization of the ZnO-PVA films strongly depends on radiation dose. The roughness of the thin film surface which can be seen by conducting Atomic force microscopy (AFM) measurement became smoother as the gamma radiation increased. The presence of Escherichia coli as a bacterial contamination in water was identified by measuring the changes of conductivity of thin films using current–voltage (I-V) measurement. The sensitivity of the sensors has been observed to be higher at a higher radiation dose.
ZT Measurements of Thermoelements under Large Temperature Difference
Authors: Yatim Nadhrah Md , Min Gao
Published: June 2015

The thermoelectric dimensionless figure-of-merit, ZT, which consists of the Seebeck coefficient, α, electrical resistivity, ρ and thermal conductivity, λ, is an important parameter that characterizes the energy conversion performance of thermoelectric materials and devices. Current techniques for determining ZT involve measurements these three properties individually or ZT directly, but all techniques are carried out under a small temperature difference (ΔT). In reality, a thermoelectric device generally operates under a much larger ΔT and with an electrical current flowing through the thermoelectric materials. A novel principle for ZT measurement has been proposed, which has the capability of measuring ZT values under a large ΔT and with an electrical current flowing through the samples. Although this technique has been proof experimentally using thermoelectric module, its implementation on thermoelement has proved to be very challenging due to low electrical resistance of the samples. In this paper, newly develop apparatus with a modified operating principle was proposed and carried out. The performance of this system was investigated using a standard n-type Bi2Te3 sample. The results show that the system has a repeatability of <10% and an accuracy of 13-32%. Investigation on single materials structures showed that there were noticeable differences between a small and a large ΔT, which can be attributed to the Thomson effect and changes in ρλ values.
Effect of Cu Addition onto CaO/Al2O3 Catalyst for Naphthenic Acid Removal from Crude Oil
Authors: Mohd Shohaimi Norshahidatul Akmar , Jaafar Jafariah , Wan Abu Bakar Wan Azelee
Published: June 2015

Oil is one of the most important energy sources for the world and will likely remain so for many decades, even in the most optimistic projection about the growth of alternative energy sources. Petroleum industry nowadays faced a problem when the naphthenic acid (NA) compound naturally present in the acidic crude oil tends to induce corrosion in oil refining process. Total Acid Number (TAN) represent the amount of naphthenic acid in the oil with the permissible limit of TAN in crude oil is less than 1. Various methods had been used to remove NA in crude oil such as dilution and caustic washing. But all methods have their own weakness. Hence, in order to overcome the acidic crude oil problem, a new catalytic deacidification technique will be introduced in this study. Three types of crude: Petronas Penapisan Melaka Heavy Crude (Crude A) and Light Crude (Crude B) and Korean Crude (Crude C) were studied. Parameters studied were dosing amount of basic chemical used, catalyst calcination temperature, and percentage of the basic chemical in the co-solvent. The basic chemical used in this study was ammonia solution in ethylene glycol (NH3-EG). By using Ca/Al2O3 catalyst with calcination temperature of 10000C, the results showed 66.7% (1000 mg/L of NH3-EG) reduction in TAN for crude A, 53.9% reduction for crude B while for crude C the percentage of TAN reduction was 41% only. Addition of Cu as a dopant in this study had increased the TAN reduction for all three types of crude oil. TAN in crude A (80% of TAN reduction) and crude B (77% of TAN reduction) were successfully reduced to less than 1 with only using 1000 mg/L of NH3-EG with the aids of Cu/Ca (10:90)/Al2O3 catalyst at calcination temperature of 10000C while for crude C the TAN was still higher than 1 but the percentage of TAN reduction increased to 46%.
Green Technology Purification of Nature Gas via CO2/H2 Methanation by Using Trimetallic Ru/Mn/Fe-Al2O3 Oxide Catalyst
Authors: Ab Halim Ahmad Zamani , Ali Rusmidah , Wan Abu Bakar Wan Azelee
Published: June 2015

The presence high content of carbon dioxide (CO2) and hydrogen sulphide (H2S) in crude natural gas which can block cryogenic equipments and favours steel-pipes corrosion thus will decrease the quality of the natural gas. Therefore, there is need to treat sour to sweet natural gas by using green technology via catalytic methanation reaction by converting CO2 to methane gas. Using waste to wealth concept, production of methane would increase as well as creating environmental friendly approach for purification of natural gas. In this work, the investigations of new trimetallic Ru/Mn/Fe-Al2O3 oxide catalysts were conducted and the catalysts were prepared by wet impregnation method. The catalysts were activated at different temperatures (100-1100°C) for 5 hours and at different ratios of metal. The additions of Ru into catalysts had improved the CO2 conversion and CH4 formation compared with the undoped. Ru/Mn/Fe (5:35:60)/Al2O3 catalyst calcined at 1000°C was assigned as the most potential catalyst, which gave 96.1% CO2 conversion at reaction temperature of 270°C. Moreover, the XRD diffractograms showed that the catalyst calcined at high temperature were highly crystalline phase while, catalysts calcined at low temperature showed highly amorphous in structure which was dominated by Al2O3 support material. The FESEM analysis revealed that fresh and used catalyst were covered with homogeneously dispersed and small size surface particles in the range of 0.2-0.4 μm. Nitrogen adsorption analysis showed, the surface area increased from single to bimetallic and trimetallic catalyst.
ESR Study of K-Mo2C for Increased Catalytic Properties
Authors: Yacob Abd Rahim , Amat Mustajab Mohd Khairul Asyraf , Suhaimi Nurshaira Haifa
Published: June 2015

The presence of potassium in molybdenum carbide morphology has been reported to increase the selectivity and reactivity of its catalytic properties. Potassium with its tendency to donate electron will enhance the electron density at the surface of catalyst by donating its electron at the vacant orbital framework either to carbon or metal moiety. This phenomenon will cause temporary paramagnetic properties of the catalyst and can be easily detected using an ESR spectrometer. In this paper, an ESR-based study to identify and prove that donating electron does take place at Mo2C after being promoted with potassium was conducted. Introduction of H2 and UV radiation were also carried out for comparison.The result from ESR spectra showed that in the absence of potassium in the Mo2C, no ESR signal was observed. However, in the presence of potassium, a singlet peak with g value ca. 1.9723 was found. The presence of a single peak indicated that the donated electron did not interact with any nearby nucleus in the surroundings. Deviation value of 2.0023 for free electron, indicates that this donated an electron probably interacted with an empty 4d orbital from molybdenum or 2p orbital from carbon.In the introduction of H2 gas and UV radiation, the finding showed that an increasing trend of singlet peak in the ESR spectrum earlier was observed. The trend indicated that the splitting of H2 by UV radiation generated new electron and joined the donated electron from K circulating at the surface of K-Mo2C morphology without interacting with another nucleus.
Calculation of Electron Density Distribution in Cd0.5Zn0.5S by Density Functional Theory: Exploring its Bonding Character and Stability
Authors: Othman A.P. , Aadenan Amin , Anas Muhammad Mus Ab , Gopir G.A.
Published: June 2015

The topology of electron density is a sketch that gives a clear picture about electronic distribution and details information of natural molecular bonding. In quantum mechanics or particularly in quantum chemistry, the electron density is a measure of the probability of an electron occupying at any infinitesimal element of space surrounding at any given point.Studies about the topology of electron density in Cd0.5Zn0.5S at plane (101) were conducted by the application of density functional theory (DFT) within linear augmented plane wave (LAPW) by using the WIEN2k software. In this calculation, generalized gradient approximation (GGA) methods were used to calculate the exchange-correlation potential of the electrons. Based on this calculation, the topology of electron density were presented in a contour plot (2D) and also inarelief map plot (3D) in order to see the way electron density, ρ of Cd0.5Zn0.5S defines the gradient field and hence the bonding type. From these plots, we identified the bond paths that coincide with the contours of electron to suggest that Cd0.5Zn0.5S exhibited characteristics of covalent and a slightly ionic bond character.
Fabrication and Properties of Multi-Walled Carbon Nanotubes Buckypaper
Authors: Wan Dalina W.A.D. , Mariatti M. , Tan Soon Huat , Mohd Ishak Z.A. , Mohamed Abdul Rahman
Published: June 2015

Free-standing carbon nanotubes (CNTs) film known as buckypaper is a method used to address dispersion problems of CNTs. Unique properties of CNTs made the CNTs buckypaper to be considered as promising reinforcement materials in development of high-performance of nanocomposites. Buckypaper was fabricated by dispersing multi-walled carbon nanotubes (MWCNTs) in two different types of solution namely Triton X-100 and ethanol then followed by filtration process. In this study, MWCNTs loading and pressure used during filtration process were manipulated. The morphology, thermal and electrical conductivity of the buckypaper produced was studied.
Transport Characteristics of Secondary Charged Particles Resulting from High Energy Neutron in Silicon
Authors: Abdul Amir Haider F. , Chee Fuei Pien
Published: June 2015

Silicon is always the dominant semiconductor material of the modern semiconductor industry. This is as silicon can retain its semiconductor characteristics even at a higher temperature while the other semiconductor materials can't. However, when a silicon device is exposed to a flux of energetic radiation or particles, the effects from the radiation and the induced secondary particles can cause several degradation of the device performance. For the purpose of investigate the resultant effects from the bombardment of neutrons and the behavior of secondary charged particles in the silicon model, the neutron displacement defect was measured in situ and then followed by the simulation based on Monte Carlo method. The bombardment of neutron in the silicon model produce at least three secondary particles, which are alpha ˸α˹ particles, proton (p) particles and silicon recoil atoms, through the reactions of ˸̾˼α˹˼˰˸̾˼̀˹˰and neutron scattering respectively. The kinetic energy and range of these charged particles are different among themselves, and thus the probability of hitting and degradation effects in the silicon materials are varies. The simulation calculation showed that ˸̾˼α˹˰reaction induced soft error cross section of about 8.7 x 10-14 cm2 and for recoil atoms, it is about 2.9 x 10-15 cm2. There was no error of the silicon device configuration induced by proton particles until 1010 n/cm2.neutron fluence. It can be concluded that the largest portion of error in the silicon model is induced by the secondary alpha ˸α˹ particles.
Attenuated Total Reflection Studies of Honeycomb Nanoporous GaN Thin Films
Authors: Cheah Sook Fong , Lee Sai Cheong , Ng Sha Shiong , Yam Fong Kwong , Haslan Abu Hassan , Zainuriah Hassan
Published: June 2015

In this work, room temperature polarized infrared attenuated total reflection (ATR) spectroscopy was employed to characterize a nanoporous GaN thin film with honeycomb structure. Prominent ATR dips due to the surface phonon polariton (SPP) and guided waves of nanoporous GaN thin film were observed. Both SPP resonance and guided waves were detected in the p-polarized ATR spectrum while only guided waves were detected in the s-polarized ATR spectrum. The ATR results were compared with the theoretical spectra generated by means of effective medium model. Good agreement was achieved between the measured and theoretical spectra. Finally, the thickness and porosity of porous layer were determined unambiguously.
Effects of Mechanical Alloying on the Structure and Properties of Iron Powders
Authors: Lemdani F. , Azzaz Mohammed , Taïbi K. , Lounis A.
Published: June 2015

A nanostructured iron, elaborated from pure elemental powders by mechanical milling at high energy was characterized by different types of technical of analysis. Scanning electron microscopes (SEM) and laser scattering machine have showed the variation in the size and the shape of particles according to different milling times. Powders obtained were characterized with X-ray diffraction (XRD) , the latter diffraction patterns indicated the body centered cubic (bcc) structure. The crystalline grain was about 13 nm size after only a few hours of milling time. The measurement of both coercive field (Hc) and maximal magnetization (Ms) revealed a change in the magnetic behavior of our samples.
Emission Nuclear Gamma-Resonance Spectroscopy of Grain Boundaries in Coarse-Grained and Ultrafine-Grained Polycrystalline Mo
Authors: Popov Vladimir V. , Sergeev A.V. , Stolbovsky A.V.
Published: June 2015

Grain boundaries in coarse-grained Mo with grain boundaries of recrystallization origin and in ultrafine-grained (UFG) Mo obtained by high pressure torsion have been studied by the emission Mössbauer spectroscopy on the57Co (57Fe) nuclei. It is demonstrated that Co atoms diffuse along grain boundaries by interstitials. The temperature dependence of grain-boundary segregation factor of Co in coarse-grained Mo has been determined. It is shown that the state of Co atoms in grain boundaries and near-boundary areas in UFG Mo differs from that in coarse-grained Mo.
Interdiffusion and Reaction between Pure Magnesium and Aluminum Alloy 6061
Authors: Kammerer C.C. , Fu M. , Zhou Le , Keiser Dennis D. , Sohn Yong Ho
Published: June 2015

Using solid-to-solid couples investigation, this study characterized the reaction products evolved and quantified the diffusion kinetics when pure Mg bonded to AA6061 is subjected to thermal treatment at 300°C for 720 hours, 350°C for 360 hours, and 400°C for 240 hours. Characterization techniques include optical microscopy, scanning electron microscopy with X-ray energy dispersive spectroscopy, and transmission electron microscopy. Parabolic growth constants were determined for γ-Mg17Al12, β-Mg2Al3, and the elusive ε-phase. Similarly, the average effective interdiffusion coefficients of major constituents were calculated for Mg (ss), γ-Mg17Al12, β-Mg2Al3, and AA6061. The activation energies and pre-exponential factors for both parabolic growth constant and average effective interdiffusion coefficients were computed using the Arrhenius relationship. The activation energy for growth of γ-Mg17Al12 was significantly higher than that for β-Mg2Al3 while the activation energy for interdiffusion of γ-Mg17Al12 was only slightly higher than that for β-Mg2Al3. Comparisons are made between the results of this study and those of diffusion studies between pure Mg and pure Al [1] to examine the influence of alloying additions in AA6061.
Prediction of Diffusion Coefficients in Liquid and Solids
Authors: Wang William Yi , Zhou Bi Cheng , Han Jia Jia , Fang Hua Zhi , Shang Shun Li , Wang Yi , Hui Xi Dong , Liu Zi Kui
Published: June 2015

Our activities in predicting diffusion coefficients in fcc, bcc, and hcp solid solutions using first-principles calculations and in liquid usingabinitiomolecular dynamics are reviewed. These include self-diffusion coefficients [1-4], tracer diffusion coefficients in dilute solutions [5-7], calculation of migration entropy [8], tracer diffusion coefficients in metallic and oxide liquid [9, 10], and effects of vacancy on diffusion of oxygen [11, 12]. The effects of exchange correlation functionals are examined in some cases along with charge transfer between solute and solvent elements. The dominant contribution of diffusion on the effects of Re addition on the creep properties of Ni-base superalloys is discussed [13].
Direct Numerical Simulation of the Pressure Drop through Structured Porous Media
Authors: Malico I. , Ferrão C. , Ferreira de Sousa P.J.S.A.
Published: June 2015

This paper presents direct numerical simulations for the flow through regular porous media composed of equal size staggered square cylinders obtained with a compact finite differences immersed boundary method. Different moderate Reynolds numbers are simulated in order to capture the dependence of the pressure drop with the Reynolds number in the Forchheimer regime. The pressure drop predictions agree well with the Hazen-Dupuit-Darcy model; however, when compared to a widely used semi-empirical correlation, the modified Ergun equation, the agreement is poor. A better agreement is found if the particle diameter is taken to be equal to the cylinder diameter. From the intrinsic-averaged pressure calculated along the flow direction, it can be seen that, for the porous media studied, the bulk pressure drop dominates and the entrance and exit effects are negligible.
Comparison of Electrochemical and Chemical Corrosion Behavior of MRI 230D Magnesium Alloy with and without Plasma Electrolytic Oxidation Treatment
Authors: Kazanski Barbara , Lugovskoy Alex , Gaon Ohad , Zinigrad Michael
Published: June 2015

Magnesium is one of the lightest metals and magnesium alloys have quite special properties, interest to which is continuously growing. In particular, their high strength-to-weight ratio makes magnesium alloys attractive for various applications, such as transportation, aerospace industryetc. However, magnesium alloys are still not as popular as aluminum alloys, and a major issue is their corrosion behavior.The present research investigated the influence of the PEO treatment on the corrosion behavior of MRI 230M magnesium alloy. Plasma electrolytic oxidation (PEO) of an MRI 230M alloy was accomplished in a silicate-base electrolyte with KF addition using an AC power source.The corrosion behavior of both treated and untreated samples was evaluated by open circuit potential (OCP) measurements, electrochemical impedance spectroscopy (EIS), linear polarization tests, linear sweep voltammetry (Tafel extrapolation) and chemical methods, such as mass loss and hydrogen evolution, in neutral 3.0 wt% NaCl solution.According to the tests results, PEO process can affect the corrosion resistance of MRI 230M magnesium alloy, though its action is not always unambiguous. An attempt to explain the influence of the PEO treatment on the corrosion behavior of the alloy is presented.
Adsorption of Nitrogen Contaminants in the Light Gas Oil (LGO) and Light Cycle Oil (LCO) to Produce Diesel with Low Sulfur
Authors: Figueiredo M.A.G. , Souza W.C. , Corrêa Harrison , Ventura L.B. , Corrêa H.L. , Chiaro S.S.X. , Souza R.J.F.
Published: June 2015

Ultra-low sulfur diesel (ULSD) is obtained by Light Gas Oil (LGO) and Light Cycle Oil (LCO) feedstocks (middle fractions from distillate petroleum). In addition to the environmental requirements related to the production of fuels with a lower content of nitrogen, technical specifications refineries also stimulate the need to remove such compounds. Nitrogenous compounds, for example, are strong inhibitors for hydrodesulfurization reactions. As Brazilian oil has a high amount of nitrogen compounds, an alternative process for nitrogen removal has been investigated, such as adsorption. In this paper, the nitrogen removal was investigated. The adsorption tests were carried out in a shaking water batchs, by performing kinetic and isotherm tests. Two commercial clays were used: Fuller's earth and bentonite.
The Interpretation of Marker Experiment Conducted during Formation of Higher Oxide on the Surface of Lower Oxide
Authors: Grzesik Zbigniew , Smola Grzegorz , Mrowec Stanisław
Published: June 2015

The marker method in studying the formation mechanism and defect structure of higher oxide during oxidation of lower oxide has been discussed. The approach to this problem needs specific treatment, both in experimental procedure and in the interpretation of results. It has been shown that the correct results of marker experiments in the case of highly defected substrates can be obtained, if these substrates before the marker deposition process are submitted to homogenization under highest oxidant activity, at which they remain stable at a given temperature. In addition, the nonstoichiometry must be considered in formulating appropriate chemical reactions, being the basis for foreseeing the location of markers in the interior of reaction product. The other very important problem consists in the possibility of the formation of reaction product not only on the surface of oxidized substrate but also inside of this substrate. In such a situation, the formulation of final conclusions concerning the crystalline lattice disorder from marker position should be combined with considerations of chemical reactions and transport processes occurring in a given substrate.
Multi-Scale Modeling of Internal Mass Diffusion Limitations in CO Oxidation Catalysts
Authors: Navalho J.E.P. , Pereira J.M.C. , Pereira J.C.F.
Published: June 2015

This work applies a 3D multi-scale bottom-up approach for modeling the processes of diffusion and reaction-diffusion in porous catalyst layers. The performance of the random pore model to predict effective transport coefficients are compared with the results of the multi-scale diffusion model. The results of the 3D multi-scale diffusion model are employed in a 1D pseudo-homogeneous reaction-diffusion model with a relative good agreement with the 3D multi-scale reaction-diffusion model. Furthermore, the former multi-scale model was coupled to a full-scale reactor model with good results and high advantages in terms of computational time savings.
Treatment modalities of necrobiosis lipoidica: a concise systematic review
Authors: Feily Amir , Mehraban Shadi
Published: June 2015

Necrobiosis lipoidica (NL) is a rare inflammatory granulomatous skin disorder closely associated with diabetes mellitus. The aim of this paper is to review and discuss all the treatment modalities proposed and tested for this disease. A systematic review of the existing literature was conducted to investigate all the available data and summarize all the clinical trials, case reports and original articles on NL. Two major databases (PubMed and Google Scholar) were used. We have examined about 70 articles. Numerous treatment modalities have been currently investigated to compare recalcitrant NL. Being rare, most of the studies regarding this disease are case reports or small-scale clinical trials. We have found that, in spite of plentiful investigations carried out during the years, there is no treatment modality that has proved to be utterly satisfactory in treating NL.
Beaufort Sea coastal sediment study: numerical estimation of sediment transport and nearshore profile adjustment
Authors: Pinchin B M , Nairn R B , Philpott K L
Published: June 2015

This report responds to a need for better data on coastal processes in the Canadian Beaufort Sea required by Government and by the Oil and Gas Industry for the siting and design of new shore-base facilities. Numerical estimates of alongshore sediment transport
and nearshore profile adjustments are developed for the following sites: Atkinson Point, N.W.T.; Kay Point, Yukon; King Point, Yukon; North Head, N.W.T.; Stokes Point, Yukon; and Tuktoyaktuk, N.W.T. The influence of storm surges of coastal processes is also investigated. The evolution on the
shoreline at King Point under existing conditions and with a total littoral barrier structure has been modelled. Offshore and nearshore wave climates have been computed for seven sites; the six mentioned plus Pauline Cove on Herschel Island. They are based on new fourteen-year parametric hindcasts.
The inshore wave climates were computed using two-dimensional spectral transfer techniques with allowance for shallow water equilibrium spectral forms. The report is in two Parts: Part I comprises the full text with summaries of results; Part II comprises seven complete data packages, one for each
of the sites considered.
The expression patterns of Cucumis sativus WRKY (CsWRKY) family under the condition of inoculation with Phytophthora melonis in disease resistant and susceptible cucumber cultivars
Authors: Xu Xiaomei , Wang Rui , Chao Juan , Lin Yu′e , Jin Qingmin , He Xiaoming , Luo Shaobo , Wu Tingquan
Published: June 2015

Xu, X., Wang, R., Chao, J., Lin, Y., Jin, Q., He, X., Luo, S. and Wu, T. 2015. The expression patterns of Cucumis sativus WRKY (CsWRKY) family under the condition of inoculation with Phytophthora melonis in disease resistant and susceptible cucumber cultivars. Can. J. Plant Sci. 95: 1121–1131. Based on RNA-seq, we analyzed expression patterns of 55 CsWRKYs in the disease-resistant cultivar (JSH) and the disease-susceptible cucumber cultivar (B80) at 0 and 40 h post-inoculation with Phytophthora melonis. After inoculation with P. melonis, in JSH and B80, the number of up-regulated CsWRKY genes was both 25 with 22 commonly up-regulated genes, and there were 22 CsWRKY genes down-regulated in JSH and 23 in B80 with 18 commonly down-regulated genes, and there were eight CsWRKY genes with no or little change in transcript expression in JSH and seven in B80 with four common genes. Among the 55 CsWRKY genes, 17 genes showed significant differences (differences > twofold) in the degree of change of gene transcription level between JSH and B80 from RNA-seq data analysis, and the results validated using real-time PCR showed that there were only six genes (CsWRKY2, 20, 26, 35, 44, 52) out of the 17 that exhibited significant differences (differences > twofold) with four genes (CsWRKY2, 20, 26, 52) consistent with the data from RNA-seq and two genes (CsWRKY 35, 44) inconsistent with the data from RNA-seq. In addition, the six genes were strongly up-regulated after salicylic acid (SA) treatment with five genes (CsWRKY2, 20, 26, 35, 44) up to peak at 12 h and one gene (CsWRKY52) up to peak at 24 h in expression and that four CsWRKY genes (CsWRKY2, 20, 44, 52) out of six were strongly up-regulated with three genes (CsWRKY2, 20, 44) up to the highest point at 24 h and one gene (CsWRKY52) up after methyl jasmonate (MeJA) treatment. Based on the results above, we predicted CsWRKY2, 20, 26, 35, 44 and 52 may be involved in disease resistance of JSH against Phytophthora melonis by SA and (or) JA signaling pathway(s).
On the growth of the first Betti number of arithmetic hyperbolic 3-manifolds
Authors: Kionke Steffen , Schwermer Joachim
Published: June 2015

We give a lower bound for the first Betti number of a class of arithmetically defined hyperbolic

3

-manifolds and we deduce the following theorem. Given an arithmetically defined cocompact subgroup

\Gamma \subset \mathrm {SL}_2(\mathbb C)

, provided the underlying quaternion algebra meets some conditions, there is a decreasing sequence

\{\Gamma_i\}_i

of finite index congruence subgroups of

\Gamma

such that the first Betti number satisfies

b_1(\Gamma_i) \gg [\Gamma:\Gamma_i]^{1/2}

as

i

goes to infinity.
Indecomposable $F_N$-trees and minimal laminations
Authors: Coulbois Thierry , Hilion Arnaud , Reynolds Patrick
Published: June 2015

We extend the techniques of [8] to build an inductive procedure for studying actions in the boundary of the Culler–Vogtmann Outer Space, the main novelty being an adaptation of the classical Rauzy–Veech induction for studying actions of
surface type
. As an application, we prove that a tree in the boundary of Outer space is free and indecomposable if and only if its dual lamination is
minimal up to diagonal leaves
. Our main result generalizes [3, Proposition 1.8] as well as the main result of [22].
Regionalisation of groundwater droughts using hydrograph classification
Authors: Bloomfield J. P. , Marchant B. P. , Bricker S. H. , Morgan R. B.
Published: June 2015

Abstract. Groundwater drought is a spatially and temporally variable phenomenon. Here we describe the development and application of a method to regionalize and quantify groundwater drought based on categorisation of Standardised Groundwater level Index (SGI) time series. The categorisation scheme uses non-hierarchical k-means cluster analysis. This has been applied to 74 SGI time series for the period January 1983 to August 2012 for a case study from Lincolnshire, UK. Six SGI time series clusters have been identified. For each cluster a correlation can be established between the mean SGI and a mean Standardised Precipitation Index (SPI) associated with an optimal SPI accumulation period, qmax. Based on a comparison of SPI time series for each cluster and SPI estimated for the whole study area, it is inferred that the clusters are largely independent of heterogeneity in the diving meteorology across the study region and are primarily a function of catchment and hydrogeological factors. This inference is supported by the observation that the majority of sites in each cluster are associated with one of three principal aquifers in the study region. The groundwater drought characteristics of the three largest clusters (CL1, CL2 and CL4 that constitute ~80% of the sites) have been analyzed. There is a common linear relationship between drought magnitude and duration for each of three clusters. However, there are differences in the character of the groundwater drought events between the three clusters as a function of autocorrelation of the mean SGI time series for each cluster. For example, CL1 has a relatively short period of significant SGI autocorrelation compared with CL2 (15 and 23 months respectively); CL1 has more than twice the number of drought episodes (39 episodes) than CL2 (15 episodes), and the average and maximum duration of droughts in CL1 (4.6 and 27 months) are less than half those of CL2 (11.3 and 61 months). The drought characteristics of CL4 are intermediate between those of CL1 and CL2. Differences in characteristics between the three clusters are also seen in their response to three major multi-annual droughts that occurred during the analysis period. For example, sites in CL2 with the longest SGI autocorrelation experience the greatest magnitude droughts and are the slowest to recover from drought, with groundwater drought conditions typically persisting at least six months longer than at sites in the other two clusters. Membership of the clusters reflects differences in the autocorrelation of the SGI time series that in turn is shown to be related to unsaturated zone thickness at individual boreholes. This last observation emphasises the importance of catchment and aquifer characteristics as (non-trivial) controls on groundwater drought hydrographs.
Water level oscillations in Monterey Bay and Harbor
Authors: Park J. , Sweet W. V. , Heitsenrether R.
Published: June 2015

Abstract. Seiches are normal modes of water bodies responding to geophysical forcings with potential to significantly impact ecology and maritime operations. Analysis of high-frequency (1 Hz) water level data in Monterey, California, identifies harbor modes between 10 and 120 s that are attributed to specific geographic features. It is found that modal amplitude modulation arises from cross-modal interaction and that offshore wave energy is a primary driver of these modes. Synchronous coupling between modes is observed to significantly impact dynamic water levels. At lower frequencies with periods between 15 and 60 min, modes are independent of offshore wave energy, yet are continuously present. This is unexpected since seiches normally dissipate after cessation of the driving force, indicating an unknown forcing. Spectral and kinematic estimates of these low-frequency oscillations support the idea that a persistent anticyclonic mesoscale gyre adjacent to the bay is a potential mode driver, while discounting other sources.
Ebola virus disease in pregnancy and anesthetic considerations
Authors: Ranasinghe J. Sudharma , Missair Andres , Moaveni Daria , Zahid Zahira , Hochman-Cohn Jennifer
Published: June 2015

Ebola virus disease (EVD) is often lethal, mortality rates range from 50% to over 90%, depending on the patient population, viral strain, and access to medical care. During pregnancy, the morbidity and mortality from the viral disease has been suggested to be among the highest of any affected patient population. According to the existing literature, which is confined to a few small case series in Africa, the risk of spontaneous fetal loss is high and there have been no known neonatal survivors. The mode of EVD transmission is well understood and evidence from the current and previous epidemics indicates that transmission can be interrupted by infection control measures. The central element of providing care to a patient suspected of Ebola is a three-step triage process: identify/isolate/inform. Once the diagnosis is confirmed, because of the potentially worse outcomes seen in pregnancy, specialized multidisciplinary care may be needed. In addition, especially in the obstetric setting, there is a high likelihood of exposure to a potentially deadly disease by health care workers. Therefore, these patients should be managed by anesthetic and obstetric providers in centers with expertise, protocols and training. Labor pain management, and the decision to proceed with cesarean delivery or other obstetric interventions will need to be considered on a case-by-case basis, weighing the risks and benefits to the mother, the fetus and the caregivers.
De economische werkelijkheid en enquêtebevoegdheid
Authors: van Dalen S.F.
Published: June 2015

De economische werkelijkheid en enquêtebevoegdheid

De afgelopen jaren is bij het toekennen van enquêtebevoegdheid een aantal keren anders geoordeeld dan de tekst van de wet doet verwachten. Volgens de rechter speelt daarbij de economische werkelijkheid een belangrijke rol. Dit is een onduidelijk en voor meerdere interpretaties vatbaar begrip. Volgens de auteur vormt dit begrip een beoordelingskader waarbinnen de rechter feiten en omstandigheden afweegt. Dit beoordelingskader is nuttig, het biedt de ruimte om aan te sluiten bij de doeleinden van het enquêterecht. Spreken van de ‘achterliggende werkelijkheid’ in plaats van ‘economische werkelijkheid’ zou de onduidelijkheid kunnen wegnemen. De rechter kan dan via enerzijds de afgeleideleer en anderzijds de gelijkstellingsregel afwijken van een al te strikte toepassing van de wettelijke bepaling, indien de achterliggende werkelijkheid dit rechtvaardigt.
Gerechtelijke toetsing bij herroeping van een ontbindingsbesluit van een rechtspersoon
Authors: Groenland I.
Published: June 2015

Gerechtelijke toetsing bij herroeping van een ontbindingsbesluit van een rechtspersoon. Hoe de Hoge Raad zijn doel voorbijstreeft met onnodig complicerende voorwaarden

In de Rifgat-beschikking van 19 december 2014 (ECLI:NL:HR:2014:3677) heeft de Hoge Raad niet alleen bevestigd dat herroeping van een ontbindingsbesluit mogelijk is, maar ook de daarvoor geldende voorwaarden bepaald. De Hoge Raad geeft daarbij aan dat hij daarmee een leemte vult in de wetgeving en dat het eigenlijk aan de wetgever is om te voorzien in een afgewogen regeling. De door de Hoge Raad geformuleerde voorwaarden lijken echter niet aan te sluiten bij het beoogde doel. Daarnaast blijken deze bij toetsing aan het feitencomplex in de Rifgat-casus niet te leiden tot een redelijke uitkomst. Het verbinden van bijzondere voorwaarden aan herroeping van een ontbindingsbesluit is, gezien de ontwikkelingen in wetgeving, rechtspraak en literatuur, ook niet langer nodig. Een eenvoudige wettelijke regeling voor herroeping van besluiten is daarom, juist na deze Hoge Raad-beschikking, dringend gewenst.