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In this paper, the impact of small additions of indium (In), nickel (Ni), and Titanium dioxide nanoparticles (TiO2 NPs) in the microstructure and characterization of eutectic Sn–0.7 Cu (SC07)-based solder were investigated. The third element In, Ni, or TiO2 NPs were added in varying amounts 0.4 or 0.8 wt% to SC07 alloy by replacing an equal amount of Sn for each addition. Structural analysis of the investigated samples showed that the addition of Ni or In modified the eutectic composition, leading to the appearance of primary phases (Cu6Sn5) followed by the formation of intermetallic compounds (IMCs) (Cu, Ni)6Sn5 and Cu6(Sn, In)5. However, addition of TiO2 NPs did not lead to formation of any new IMCs but refine β-Sn dendrites grains with a decrease in the volume fraction of Cu6Sn5 IMC. The crystallite size, lattice strain, and dislocation density of the SC07 solder alloy were improved in terms of third addition. The results indicated that the smallest crystallite size for SC07–0.8In associated with largest lattice strain and highest dislocation density. Microhardness tests were performed for all samples at room temperature. The results illustrate the enhancement indentation creep resistance of SC07 reinforced solder, which inherently correlates to the microstructure refinement and the formation of intermetallic phases (Cu, Ni)6Sn5 and Cu6(Sn, In)5 with higher hardness values. The obtained stress exponent values are in the range 9.26–11.46 for all tested alloys which close to that creep mechanisms associated with dislocation movement such as dislocation creep are predominant. Thus, we conclude that the greatest value of stress exponent for SC07–0.8In (10.9–11.46) at different loads suggested to be more resistant to indentation creep which improves the mechanical strength compared to other solders. [ABSTRACT FROM AUTHOR]

The time-dependent electrophoresis of an infinitely cylindrical particle in an electrolyte solution, saturated in a charged porous medium after the sudden application of a transverse or tangential step electric field, is investigated semi-theoretically with an arbitrary double-layer thickness in an arbitrary direction relative to the cylinder. The time-dependent modified Brinkman equation with an electric force term, which governs the fluid flow field, is used to model the porous medium and is solved by using the Laplace transform technique. Explicit formulas, for the time-dependent electrophoretic velocity of the cylindrical particle in Laplace's transform domain, have been derived for both axially and transversely when the uniform electric fields are imposed. They can also be linearly superimposed for an arbitrarily oriented relative to the electric field. Semi-analytical results for the electrophoretic velocities are presented as functions of the dimensionless elapsed time, the ratio of the particle radius to the Debye length, the particle-to-medium density ratio, and the permeability parameter of the porous medium. The results demonstrate, in general, that the growth of the electrophoretic velocities with the time scale are more slower for high permeability, and the effect of the relaxation time for unsteady electrophoresis is found to be negligible, regardless of the thickness of the double layer, the relative mass density or the permeability of the medium. The normalized transient electrophoretic velocities exhibit a consistent upward trend as the ratio of the particle radius to the Debye screening length increases. Conversely, they display a consistent downward trend as the particle-to-fluid density ratio increases, while all other parameters remain constant. The effect of the relaxation time for the transient electrophoresis is much more important for a cylindrical particle than for a spherical particle due to its smaller specific surface area. [ABSTRACT FROM AUTHOR]

This work involved the synthesis of compositions of Ba0.95Ca0.05SnxTi1-xO3 (BCST) with varying amounts of Sn dopant (x = 0, 0.02, 0.04, 0.06, 0.08, and 0.1). A standard solid-state reaction approach was used to create all of the ceramic compounds. Each BCST composite's microstructure, sintering, morphology, density, optical, and electrical characteristics were carefully examined, and the dielectric performance was optimized. In comparison to the unmodified composite, introducing varied amounts of Sn material into the BCST compound changed the crystal lattice vibrations and functional group locations. This result indicates that there are some variations in unit cell size, revealing that Sn+4 ions diffused effectively inside the lattice structure to produce BSCT composites. Further, SEM micrographs indicated proportionate changes in the homogenous structure and irregular forms as Sn concentration increased, as well as some variation in average grain size. As a consequence, by adding 0.08 mol% of Sn dopant, the crystallite size and average grain size were adjusted to 45.69 nm and 0.66 µm, respectively. Meanwhile, the 0.08-Sn specimen displayed a dielectric constant (Ɛ) with an optimum value of 5557 and a relative decrease in the Curie-Weiss constant. These results are attributed to the existence of various concentrations of Sn ions at the Ti-site of the BCT, which resulted in a compositionally disordered state. This disordered condition is essential for the production of dielectric compounds. Therefore, it is evident that modifying the amount of Sn doping added significantly enhanced the dielectric characteristics of the BCST composites created in this work. However, excessive Sn doping reduces the dielectric properties due to a reduction in tetragonal phase and an increase of disorders and charge fluctuations. Highlights: Synthesis and characterization of Ba0.95Ca0.05SnxTi1-xO3 (BCST) compositions with varying amounts of Sn dopant. A standard solid-state reaction approach was used to create all of the ceramic compounds. The dielectric characteristics of the BCST proved to be highly dependent on the amount of Sn doping employed. [ABSTRACT FROM AUTHOR]

A CT scan of a pregnant patient is often a source of distress for the patient and staff. In addition, patients are usually worried about the risk of unfavorable effects on the fetus from radiation. Therefore, assessing radiation dose and related risks to the fetus and pregnant patient is an important aspect of radiation protection. The aim of this study is to estimate the fetal organ and effective dose during a chest CT protocol for a pregnant patient. For this purpose, we model the SOMATOM EMOTION 16 CT (Siemens Medical Solutions, Erlangen, Germany) and the pregnant patient using GATE code. The CT scanner is modelled based on the data provided by the supplier, operating at 80, 110 and 130 kV and 0.5–1.5 for the pitch, regarding the patient, she is modelled with a voxelized pregnant phantom (KATJA, 29 yr old) at the 24th week. Fetal effective doses are estimated to be 0.8, 1.7 and 2.4 mSv for 80, 110 and 130 kV, respectively. When the energy is decreased from 130 to 80 kV, the dose to the fetal organs in the heart and lenses is reduced by 64.3 and 64.6%. Moreover, the fetus organ dose is reduced by 21.5, 19.2, 30.0 and 17.6% for crane, eyes, heart and brain for a pitch ranging from 0.5 to 1.5. Since the cumulative dose to the fetus does not exceed 100 mGy, the doses to the fetus are considered acceptable. [ABSTRACT FROM AUTHOR]

The present research work aims to study the heat treatment effect on the structural and mechanical properties of the tool steel AISI D2. The steel has undergone a double treatment. First, the iron-based alloy was subjected to a normalizing, the explored temperatures are 975, 1025 and 1075°C for a holding time of 1 hour. Then, the steel is annealed at temperatures ranging from 250 to 650°C for 2 hours. The structural and mechanical properties of the tool steel AISI D2 was studied by several experimental methods: hardness measurement, optical microscopy, scanning electron microscopy and X-ray diffraction. After the heat treatments, the mechanical properties of the steel decreased compared to as-received state. According to the microscopic study, the softening is due to the precipitation of cementite present as spherical and isolated particles in a matrix of ferrite. [ABSTRACT FROM AUTHOR]

The feasibility of using nano-cryptomelane for elimination of cobalt and cesium metal ions from their single and binary solutions was studied. In this respect, the material was prepared and characterized to confirm its chemical composition and structure. Results illustrate that the synthesized nano-cryptomelane has a tunnel structure with particle size ranged between 4 and 6 nm. The material feasibility was detected by conducting a series of batch experiments for determination of the kinetic and equilibrium performance of the removal process. All characteristic Raman bands for Mn–O lattice vibrations within the (2 × 2) tunnel structure of MnO6 octahedral are observed which confirm formation of nano-cryptomelane. The specific surface area (SSA) for nano-cryptomelane was calculated and equal to 299.03 m2/g while the surface fractal information (Ds) was2.53. The process sensitivity to changes of H+ concentration is attributed to changes in structural elements-species distribution at the solid/aqueous interface. The pH optimum value was desired at pH 5 for exchange of Cs+ and/or Co2+ with K+ ions. The equilibrium studies show that Langmuir isotherm model was more fitted to the experimental data than that of Freundlich model. [ABSTRACT FROM AUTHOR]

In this study, the objective was to give more data related to the use of GATE (Geant4-based Application for Tomographic Emission) and Al2O3:C Optically Stimulated Luminescence (OSL) nanodots, as two alternative methods to estimate entrance surface dose (ESD) in mammography. First, ESD values were simulated with GATE and compared with values measured with Al2O3:C OSL nanodots and Solid State kV/dose Multisensor AGMS-M+ (Radcal,USA), using a standard breast phantom MTM100 (CIRS, USA). On the other hand, GATE simulations were also performed with PMMA slabs of different thicknesses (10 to 90 mm) and then compared with experimental values using AGMS-M+ detector. Results pointed to a maximum difference of 17%, between X-ray spectra simulated with GATE and those calculated with the IPEM report number 78 software, for this reason, the air kerma factor was calculated with GATE and IPEM and compared to the one measured by the AGMS-M+ detector. The ESD results indicate that GATE and Al2O3:C OSL nanodots values were compatible within 4% with those obtained with AGMS-M+. This work gives more data according to the use of GATE and Al2O3:C OSL nanodots to determine the ESD. Indeed, in the literature, there are few studies related to the use of GATE code and Al2O3:C OSL nanodots in mammography systems. [ABSTRACT FROM AUTHOR]

2,3,7,8,12,13,17,18-Octaethyl-21H,23H-porphine (OEP) was successfully radiolabeled with technetium-99m by direct technique using two different reducing agents: stannous chloride and sodium borohydride. High radiochemical yield (97%) and in vitro stability for up to 8 h were obtained using sodium borohydride. Paper chromatography (PC), paper electrophoresis, and high-performance liquid chromatography (HPLC) were used to evaluate the radiochemical yield and identify the purity of the final product. Biodistribution studies of the 99mTc-OEP complex (prepared using sodium borohydride) in tumor-bearing mice showed high target/nontarget (T, right thigh/NT, left thigh) ratio of 4.40 ± 0.12 at 60 min post injection, suggesting that this complex can be used as a solid tumor imaging agent. [ABSTRACT FROM AUTHOR]

Delonix regia pods have been used to produce high-efficiency and low-cost activated carbons using different activation methods. The ability of these prepared sorbents to remove cations [137Cs, 85Sr, La(III), Eu(III), Co(II), U(VI)] and anions [75Se, Cr(VI), Mo(VI)] was evaluated in mono-component systems and the sorbents number 11, 13, 25, and 35 showed high removal efficiency. These sorbents also show the high ability to remove organic pollutants such as methylene blue and phenol. This study highlighted the extensive applicability of these low-cost sorbents in the sequestration of anionic and cationic radionuclides from real radioactive wastewaters and different environmental samples. [ABSTRACT FROM AUTHOR]

This work relates to the study and characterization of the CTDI (Computed Tomography Dose Index) for the 16 slices CT scanner. The CTDI has been simulated with the Monte Carlo code GATE for PMMA (polymethylmethacrylate) digital phantoms of various diameters (1–50 cm) at various kVp (80, 110, 130) and mAs (100, 200, 300, 400 mAs) levels. After using a High-Performance Computing (HPC) station, a good agreement was observed (less than 1.18% for head phantom and 1.85% for body phantom for all applied voltages) between simulations and experimental measurements with standard PMMA phantoms. Results of simulations demonstrated the following. Firstly, GATE is an adapted tool to estimate CTDI values and can be used to optimize CT parameters in clinical applications. Secondly, Monte Carlo simulation may be able to estimate the absorbed dose when the CTDI method has limitations (use of homogeneous standards cylindrical phantom, the dose measurement in air not in tissue). [ABSTRACT FROM AUTHOR]

The temperature influence on the structural and mechanical properties of AISI 420 stainless steel is studied. The iron-based alloy underwent normalizing at three temperatures 975, 1025, and 1075°C for 1 h, followed by annealing at temperatures ranging from 250 to 650°C for 2 h. At both treatment stages, steel is air-cooled. The material was examined with nanoindentation, macrohardness, scanning electron microscopy, light microscopy, and X-ray diffraction. For each normalizing temperature, the two stages of the mechanical behavior were observed. At the first stage, in which macrohardness and nanohardness decrease slightly over temperature range of 250–450°C, and the second one is characterized by a significant loss of these mechanical properties corresponding to 550 and 650°C temperatures. At the microstructural level, softening of AISI 420 steel occurs due to dissociation of large cementite into smaller spheroids. [ABSTRACT FROM AUTHOR]

The quasi steady axisymmetrical flow of an incompressible viscous fluid past an assemblage of porous sphere situated at an arbitrary position within a virtual spherical cell along the line connecting their centers is analyzed using a combined analytical-numerical technique. At the fluid-porous interface, the stress jump boundary condition for the tangential stresses along with continuity of normal stress and velocity components are employed. The Brinkman model governs the flow inside the porous particle and the flow in the fictitious envelope medium is governed by Stokes equations. A general solution is constructed from the superposition of the fundamental solutions in the two spherical coordinate systems based on both the porous particle and virtual spherical cell. Boundary conditions on the particle's surface and the fictitious spherical envelope for four known cell models are satisfied by a collocation method for truncated series. Numerical solutions for the drag force exerted on the porous sphere in the presence of the cell are obtained for various cases of the effective distance between the center of the porous particle and the fictitious envelope, the volume ratio of the porous particle over the surrounding sphere, the viscosity ratio, the stress jump coefficient, and a coefficient that is proportional to the permeability. Streamlines in and around porous sphere are presented for the unit cell models at different values of relevant physical parameters. In the limits of the motions of the porous particle in the concentric position with the cell surface and near the cell surface with a small curvature, the numerical values of the normalized drag force are in good agreement with the available values in the literature. [ABSTRACT FROM AUTHOR]

Graphene (GR) sheets were successfully prepared via solvent interface trapping. Characterization of GR was performed using Raman spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), high-resolution transmission electron microscopy (HRTEM), and UV-Vis spectrometer. GR was trapped in gum acacia (GA) and polyacrylamide (PAAm) to form GA/PAAm/GR nanocomposite using gamma irradiation technique. In situ preparation of the magnetic nanocomposite and the magnetization was measured. Characterization the prepared nanocomposites was done using (FT-IR), (FESEM), (HRTEM), (XRD), (TGA). It can be obtained that a high swelling percent was observed for all systems that increased with time until reached the steady state after 5 h and the maximum was at pH 10. The swelling percent were ordered in sequence of GA/PAAm-magnetic > GA/PAAm/GR-magnetic > GA/PAAm > GA/PAAm/GR. The thermal stability of the magnetic nanocomposite was higher than non-magnetic one. The mechanical properties were determined using nanoindentation. The elastic modulus and the hardness of GA/PAAm matrix increased by adding GR and GR-magnetic in the nanocomposites. [ABSTRACT FROM AUTHOR]

Silicon carbide was mixed with alumina and kaolin to obtain porous alumino-silicate bonded SiC ceramics. Starch was added as sacrificial template. The mixtures were processed by hand-pressing and extrusion method. The effect of firing temperature (1450 ∘C) and the addition of starch on the composition and characteristics of fired specimens were studied. The changes in phase composition and microstructure of fired SiC specimens were followed through x-ray diffraction analysis and scanning electron microscopy, respectively. The sintering parameters and thermal oxidation in air of such specimens were determined. The results indicated that silicon carbide is oxidized during firing into silica which reacted with silica-alumina mixture forming alumino-silicate bonding. Meanwhile, starch burnt out leaving pores inside the specimens. Porous SiC specimens of 1.72 to 1.79 g.cm−2 bulk density, 40 to 45% open porosity and 250 to 350 N.cm−2 compressive strength could be obtained by using a mixture of 80 mass% SiC and 20 mass% alumina and kaolin as starting materials. The properties of porous SiC specimens depend on the type and amount of used starch. The extrusion method is favorable for preparing porous SiC articles of homogeneous microstructure and good properties. [ABSTRACT FROM AUTHOR]

Ageing of supersaturated solid solution in Pb - 3.2% Cd - 0.08% Sr alloy is studied at 20 and 80°C by measuring hardness, and light and scanning electron microscopy. Structural changes are established corresponding to stages of ageing and supersaturation. [ABSTRACT FROM AUTHOR]

In this study we compared the effect of three different concentrations of MoO3 on the corrosion of sodium phosphate glass containing lead and aluminum oxides to develop its durability. The corrosion was studied in deionized water and acidic solution of 0.1 N HCl. The dissolution mechanism is interpreted depending on the glass weight loss versus time and change in the glass surface. MoO3 had a stabilizing effect on the glass, causing a decrease in the glass dissolution rate. Acidic medium was found to strongly enhance the glass dissolution. The pH decrease in water with increase in acidic solution gives evidence of the release of some phosphorous ions to form phosphoric acid. The consequent enhancement of the glass durability was influenced by the presence of MoO3 and showed a remarkable advance by doping with 3 wt% of MoO3. FT-infrared absorption spectra of the studied glasses show IR vibrational bands due to phosphate groups mainly of the metaphosphate and pyrophosphate units together with the sharing and interference of IR vibrations due to Pb-O bonds. Gamma irradiation produces a minor effect on the IR spectra, and enhances the base glass durability at the beginning of the corrosion process, which can be related to the shielding behavior of the high lead glass. However, glass containing 3% MoO3 has the best durability and is the least affected by irradiation. The glass durability corresponding to its structure is verified by IR spectroscopy. [ABSTRACT FROM AUTHOR]

Three selected borosilicate glasses of commercial applications were prepared and studied for their corrosion behavior by the accepted grain test method towards acidic and alkaline solutions and distilled water before and after gamma irradiation. The work was supplemented by investigating the FT infrared absorption spectra of the glasses after immersion through the KBr disc technique. The same IR measurements have been repeated after gamma irradiation. Experimental weight loss data reveal limited changes which vary with the type of leaching solution and its strength. Alkali hydroxide solutions cause more weight loss than acidic solutions due to their reactions with all glass constituents including silicate and borate species beside modifier ions while distilled water and acidic solutions react or attack the modifier ions through ion exchange corrosion behavior. FTIR spectral results show characteristic vibrational peaks due to combined silicate and borate groups which reveal an interconnected compact network structure within the mid region of wavenumber range 800-1400 cm−1. This is due to the presence of four structural building units consisting mainly of SiO4 beside BO3, BO4 and AlO4 groups. The vibrational spectra slightly change with the immersion media because of the strong and compact network structure usually identified in borosilicate glasses. The commercial glass of the Schott type is the most durable studied glass because of high silica content (75%) together with combined 10% B2O3 and 5% Al2O3. Gamma irradiation results indicate minor changes in the weight loss data due to the compact network structure of the three commercial borosilicate glasses studied. [ABSTRACT FROM AUTHOR]

Symbolic regression is commonly performed using evolutionary algorithms like genetic programming (GP). The goal of this research work is to construct symbolic models from examples where a new symbolic regression approach based on artificial neural networks is proposed. This approach is composed of a long-term artificial neural network memory (LTANN-MEM), a working memory (WM) in addition to a proposed neural symbolization algorithm (NSA) which uses LTANN-MEM and WM for synthesizing symbolic models equivalent to learning examples. The proposed LTANN-MEM is composed of two separate multilayer perceptron (MLP) feed-forward neural networks as well as the working memory which is composed of a single MLP. The core idea of the proposed approach is based on memorizing the learning experience of individual perceptrons in long-term memory (LTM), so they become available to be reused in generating and developing hypotheses about the learning examples. Although this idea is generic and could be used for the purpose of symbolization in general, it is applied here in symbolic regression for Boolean domain only. The obtained results show the ability of the proposed approach to search the solutions space using learning experience stored previously in LTM to guide the search process. A comparison is done with GP and found that the proposed NSA algorithm outperforms GP in its performance when increasing the number of inputs and outputs in the same problem by comparing the number of emerged candidate solutions in both approaches. [ABSTRACT FROM AUTHOR]

The verified Darcy-Brinkman model and boundary perturbation method are used to study the Brinkman flow in a tube with a bumpy surface, assuming the amplitude of the bumps is small compared to the mean tube radius. This study is important to understand the abnormal flow conditions caused by the boundary irregularities in diseased vessels. The mean rate flow is found, up to second-order correction, as a function of circumferential and longitudinal wave numbers and the permeability parameter of the porous medium. Numerical results displaying the velocity components and bumpiness functions are obtained for various values of the physical parameters of the problem. The results are tabulated and represented graphically for various physical parameters. It is found that, for every permeability parameter and for given bump area, there exists a circumferential wave number, for which the flow resistance is minimized. The limiting cases of Stokes and Darcy's flows of the bumpiness function are discussed and compared with the available results in the literature. [ABSTRACT FROM AUTHOR]

This paper presents a boundary perturbation method of the Brinkman-extended Darcy model to investigate the flow in corrugated microannuli cylindrical tubes with slip surfaces. The stationary random model is used to mimic the surface roughness of the cylindrical walls. The tube is filled with a porous medium. We shall consider the two cases where corrugations are either perpendicular or parallel to the flow, and particular attention is given to the effect of the phase shift. The effects of the corrugations on the flow rate and pressure gradient are investigated as functions of wavelength, the permeability of the medium, the radius ratio and the slip parameter. Particular surface roughnesses are examined as special cases of stationary random surface. It is found that the effect of the partial slip is significant on the corrugation functions. The limiting cases of Stokes and Darcy's flows and no-slip case are discussed. [ABSTRACT FROM AUTHOR]

The flow problem of an incompressible axisymmetrical quasisteady translation and steady rotation of a porous sphere in an eccentric spherical container is discussed using a combined analytical-numerical technique. A continuity of velocity components and normal stress together with the stress jump condition for the tangential stress are used at the interface between porous and clear-fluid regions. The fluid flow outside the particle is governed by the classical Stokes equations while the fluid flow inside the porous region is treated by Brinkman model. In order to solve the Stokes equations for the flow field, a general solution is constructed from the superposition of the basic solutions in the two spherical coordinate systems based on both the porous sphere and spherical envelope. Solutions for translational and rotational motion of porous eccentric spherical particle in a spherical envelope are obtained using the boundary collocation technique. The hydrodynamic drag force and couple exerted by the surrounding fluid on the porous particle which is proportional to the translational and angular velocities, respectively, are calculated with good convergence for various values of the ratio of porous-to-container radii, the relative distance between the centers of the porous and container, the stress jump coefficient, and a coefficient that is proportional to the permeability. In the limits of the motions of a porous sphere in a concentric container and near a container surface with a small curvature, the numerical values of the normalized drag force and the normalized coupling coefficient are in good agreement with the available values in the literature. [ABSTRACT FROM AUTHOR]

The boundary effect on the asymmetrical motion of a porous spherical particle in an eccentric spherical cavity is investigated in the quasi-steady limit under creeping flow conditions. The porous particle translates and rotates in the viscous fluid, located within the spherical cavity, normal to the line connecting their centers. The fluid inside the porous particle is governed by the Brinkman equation. A tangential stress jump condition at the interface between the fluid and the porous particle is applied. A semi-analytical approach based on a collocation technique is used. Due to the linearity of the present problem, the flow variables for the clear fluid region are constructed by superposing basic solutions of two problems: the first one is the regular solution inside the cavity region in the absence of the porous particle where a first system of coordinates has its origin at the center of the cavity, while the second problem is the regular solution in the infinite region outside the spherical porous particle where a second coordinate system with its origin at the center of the porous particle is used. Numerical results displaying the resistance coefficients acting on the particle are obtained with good convergence for various values of the physical parameters of the problem. The results are tabulated and represented graphically. The findings demonstrate that the collocation results of the resistance coefficients are in good agreement with the corresponding results for the impermeable solid particle. [ABSTRACT FROM AUTHOR]

Hydroxyapatite (HA) nanopowders were synthesized at 70℃ by a coprecipitation method using slaked lime and phosphoric acid solution at different pH values. Ammonia was used to adjust the pH of the aquatic media during synthesis. The prepared powders were dried overnight at 100℃ and characterized for their phase composition using Fourier transform infrared spectroscopy (IR) and X-ray diffraction (XRD). Selected powder prepared at pH 11 was used for some investigations for its microstructural features as elucidated by transmission and scanning electron microscopy (TEM, SEM) and then sintered at different temperatures from 1000 to 1250℃ to determine its bulk density and apparent porosity of sintered bodies. Results indicated that hydroxyapatite nanopowder was successfully prepared by co-precipitation. A dense microstructure with grain growth of the hydroxyapatite was detected when its sintering temperature was increased. The prepared hydroxyapatite was thermally stable upon heating up to 1100℃; whereas above 1100℃ it was slightly dissociated into β-tricalcium phosphate (β-TCP) and CaO. At 1200℃ the β-tricalcium phosphate (β-TCP) formed was converted to the α-tricalcium phosphate phase (α-TCP), which was again reconverted to hydroxyapatite and almost dissociated at 1250℃. [ABSTRACT FROM AUTHOR]

Pentavalent technetium-99m dimercaptosuccinic acid (Tc-99m (V) DMSA) is reported as a useful tool for detection of residual or recurrent gliomas. We aimed to investigate the prognostic value of Tc-99m (V) DMSA brain SPECT in patients with glioblastoma multiforme (GBM). 40 patients [21 males and 19 females; mean age 48.6 ± 12.2 years] with GBM were included. Tc-99m (V) DMSA brain SPECT was done after surgery and before onset of radiation therapy or chemotherapy (Baseline study), at 4-6 weeks and at 6 months as a follow-up after therapy. The end point of the study was clinical follow-up for 2 years and/or death. 4-6 weeks after therapy, 40 and 60 % had negative and positive Tc-99m (V) DMSA for viable tumor tissues respectively ( P = 0.09). At 6 months follow-up, 62.5 % of (V) DMSA negative patients and 12.5 % of the positive subjects were responders ( P = 0.001). The median over-all survival (OS) of all patients was 12.3 month [range 5-24 month]. Patients with positive (V) DMSA had worse survival (8.87 month) compared to the negative ones (16.67 month) ( P = 0.0001). Multivariate Cox regression analysis showed that Tc-99m (V) DMSA brain SPECT studies at 4-6 weeks and 6-months follow-up were independent prognostic factors for survival [OR 1.069; 95 % CI 1.417-2.174; P = 0.03 and OR 1.055; 95 % CI 0.821-1.186; P = 0.01 respectively]. Stratification of tumors into risk groups based on prognostic parameters may improve outcome by altering or intensifying treatment methods. Technetium-99m dimercaptosuccinic acid brain SPECT may have an additional prognostic role in patients with GBM which needs further evaluation in larger future series. [ABSTRACT FROM AUTHOR]

The coupled flow problem of an incompressible axisymmetrical quasisteady motion of a porous sphere translating in a viscous fluid along the axis of a circular cylindrical pore is discussed using a combined analytical-numerical technique. At the fluid-porous interface, the stress jump boundary condition for the tangential stress along with continuity of normal stress and velocity components are employed. The flow through the porous particle is governed by the Brinkman model and the flow in the outside porous region is governed by Stokes equations. A general solution for the field equations in the clear region is constructed from the superposition of the fundamental solutions in both cylindrical and spherical coordinate systems. The boundary conditions are satisfied first at the cylindrical pore wall by the Fourier transforms and then on the surface of the porous particle by a collocation method. The collocation solutions for the normalized hydrodynamic drag force exerted by the clear fluid on the porous particle is calculated with good convergence for various values of the ratio of radii of the porous sphere and pore, the stress jump coefficient, and a coefficient that is proportional to the permeability. The shape effect of the cylindrical pore on the axial translation of the porous sphere is compared with that of the particle in a spherical cavity; it found that the porous particle in a circular cylindrical pore in general attains a lower hydrodynamic drag than in a spherical envelope. [ABSTRACT FROM AUTHOR]

The quasisteady axisymmetrical flow of an incompressible viscous fluid past an assemblage of porous concentric spherical shell-in-cell model is studied. Boundary conditions on the cell surface that correspond to the Happel, Kuwabara, Kvashnin and Cunningham/Mehta-Morse models are considered. At the fluid-porous interfaces, the stress jump boundary condition for the tangential stresses along with continuity of normal stress and velocity components are employed. The Brinkman's equation in the porous region and the Stokes equation for clear fluid are used. The hydrodynamic drag force acting on the porous shell by the external fluid in each of the four boundary conditions on the cell surface is evaluated. It is found that the normalized mobility of the particles (the hydrodynamic interaction among the porous shell particles) depends not only on the permeability of the porous shells and volume fraction of the porous shell particles, but also on the stress jump coefficient. As a limiting case, the drag force or mobility for a suspension of porous spherical shells reduces to those for suspensions of impermeable solid spheres and of porous spheres with jump. [ABSTRACT FROM AUTHOR]

Ferrite coated apatite magnetic nano-material was synthesized by a co-precipitation method and applied in removal of Eu(III) ions from aqueous solutions. The sample was firstly characterized using Fourier transform infrared spectroscopy, thermogravimetric analyses, deferential thermal analysis, X-ray powder diffraction, surface area by nitrogen adsorption and scanning electron microscopy. The results of physicochemical properties indicated that the synthesized magnetic nano-adsorbent had a crystalline structure and possessed a surface area amounted to 85.11 mg. Further, it was found to have high thermal resistance up to 600 °C and mean particle size of about 63 nm. The kinetic of Eu(III) sorption indicated that equilibrium state was attained within 12 h with using 5 mg as an appropriate nano-adsorbent weight. The sorption process was pH and ionic strength dependent. The maximum adsorbed amount of Eu(III) was attained at pH 2.5 with value reached to 157.14 mg g. Desorption of Eu(III) from loaded samples was studied using various eluents and maximum recovery was obtained using FeCl solution. [ABSTRACT FROM AUTHOR]

A simple, sensitive and fast procedure for analysis of liquid samples called flowing sample neutron activation analysis has been established based on measurement of short-lived radionuclides. This newly developed method involves continuous flowing of sample between an irradiation cell and measurement station. This arrangement makes it easy to analyze a large volume of sample and thus preconcentration steps can be avoided. Moreover, flowing sample technique feeds detector with fresh irradiated material, which maintains constant dead time during whole time of measurement; hence improves accuracy of the method. The method was tested for its repeatability, detection limits and sensitivity. Obtained limits of detection are favorably comparable with those already published in literature. [ABSTRACT FROM AUTHOR]

The Stokes axisymmetrical flow of an incompressible micropolar fluid past a viscous fluid sphere and the flow of a viscous fluid past a micropolar fluid sphere are investigated. The appropriate boundary conditions are taken on the surface of the sphere, while the proper conditions applied on the fictitious boundary of the fluid envelope vary depending on the kind of cell-model. These problems are solved separately in an analytical fashion, and the velocity profile and the pressure distribution inside and outside of the droplet are shown in several graphs for different values of the parameters. Numerical results for the normalized hydrodynamic drag force acting, in each case, on the spherical droplet-in-cell are obtained for various values of the parameters representing volume fraction, the classical relative viscosity, the micropolarity and spin parameters are presented both in tabular and graphical forms. Results of the drag force are compared with the previous particular cases. [ABSTRACT FROM AUTHOR]

The steady axisymmetric flow problem of a viscous fluid contained between two eccentric spheres that rotate about an axis joining their centers with different angular velocities is considered. A linear slip of Basset-type boundary condition at both surfaces of the spherical particle and the container is used. Under the Stokesian assumption, a general solution is constructed from the superposition of basic solutions in the spherical coordinate systems based on the inner solid particle and the spherical container. The boundary conditions on the particle's surface and spherical container are satisfied by a collocation technique. Numerical results for the coupling coefficient acting on the particle are obtained with good convergence for various values of the ratio of particle-to-container radii, the relative distance between the centers of the particle and container, the slip coefficients and the relative angular velocity. In the limiting cases, the numerical values of the coupling coefficient for the solid sphere in concentric position with the container and when the particle is near the inner surface of the container are obtained, and the results are in good agreement with the available values in the literature. The variation of the coupling coefficient with respect the parameters considered are tabulated and displayed graphically. [ABSTRACT FROM AUTHOR]

A combined analytical-numerical method is presented for the quasisteady axisymmetrical flow of an incompressible viscous fluid past an assemblage of porous eccentric spherical particle-in-cell models. The flow inside the porous particle is governed by the Brinkman model and the flow in the fictitious envelope region is governed by Stokes equations. In order to solve the Stokes equations for the flow field, a general solution is constructed from the superposition of the basic solutions in the two spherical coordinate systems based on both the porous particle and fictitious spherical envelope. Boundary conditions on the particle's surface and fictitious spherical envelope that correspond to the Happel, Kuwabara, Kvashnin, and Cunningham/Mehta-Morse models are satisfied by a collocation technique. The drag of these eccentric porous particles relative to the drag experienced by a centered porous particle are investigated as functions of the effective distance between the center of the porous particle and the fictitious envelope, the volume ratio of the porous particle over the surrounding sphere and a coefficient that is proportional to the inverse of the permeability. In the limits of the motions of the porous particle in the concentric position with cell surface and near the cell surface with a small curvature, the numerical values of the normalized drag force are in good agreement with the available values in the literature. [ABSTRACT FROM AUTHOR]

The k-method of INAA standardization has been implemented using the irradiation facilities of the fast pneumatic rabbit and some selected manually loaded irradiation positions, which designated for short and long irradiation, respectively, at Egypt second research reactor. The neutron flux parameters ( f and α) in each site have been determined using Zr-Au sets as neutron flux monitors. The reference materials coal NIST 1632c and IAEA-Soil 7 were analyzed for data validation and good agreement between the experimental values and the certified values was obtained. [ABSTRACT FROM AUTHOR]

Se and Co oxides have been applied in the present work as decolorizing agents to produce colorless glass from colored municipal glass cullet that contains high iron oxide. The results obtained showed that the Fe ions present in the glassy matrix are largely in the form of Fe3+ ions, X-ray fluorescence (XRF), Electron Spin Resonance (ESR), UV-Visible, and Fourier Transformer Infrared (FTIR) analyses were used to investigate the prepared glasses. The results reveal that all samples have a strong ultraviolet charge transfer absorption consisting of two or three bands at the wavelengths regions 228–232, 274–278, and 304–309 nm. The transmission is related to both decolorizing agent and the content of municipal glass cullet. The ESR intensity of Fe3+ signal remains unchanged in all samples. The IR data illustrate the appearance of characteristic absorption bands for each group of glasses in the following ranges ∼470, 773–1049, 1382–1617, 2323, 2919, 3436 cm−1 which can be attributed to Si-O-Si bending vibrations, Si-O-Si symmetric and anti-symmetric stretching of bridging oxygen, and stretching vibration of molecular water, respectively. The results indicate the ability to control the color of glasses by the addition of cullet wastes to commercial glass composition. [ABSTRACT FROM AUTHOR]

We reviewed the role of contrast magnetic resonance angiography (MRA) in patients with vascular disorders of the upper extremity. MRA accurately defines stenoocclusive lesions in patients with atherosclerosis and embolus. It helps to diagnose thoracic outlet syndrome, vascular malformations, and vasculitis. It demonstrates vascular injuries after blunt or occupational trauma, corkscrew collaterals in Burger's disease, and pathological vessels in malignant tumors. Also, it detects the cause of hemodialysis fistula dysfunction. We concluded that contrast MRA is a noninvasive imaging modality that can be used for planning the treatment of vascular disorders of the upper extremity. [ABSTRACT FROM AUTHOR]

This paper provides an overview of a project aimed at using knowledge-based technology to improve accessibility of the Web for visually impaired users. The focus is on the multi-dimensional components of Web pages (tables and frames); our cognitive studies demonstrate that spatial information is essential in comprehending tabular data, and this aspect has been largely overlooked in the existing literature. Our approach addresses these issues by using explicit representations of the navigational semantics of the documents and using a domain-specific language to query the semantic representation and derive navigation strategies. Navigational knowledge is explicitly generated and associated to the tabular and multi-dimensional HTML structures of documents. This semantic representation provides to the blind user an abstract representation of the layout of the document; the user is then allowed to issue commands from the domain-specific language to access and traverse the document according to its abstract layout. [ABSTRACT FROM AUTHOR]

Zirconium (IV) was determined spectrophotometrically by reaction with quercetin as primary ligand and oxalate as secondary ligand. Polyvinylpyrrolidone (PVP) was used as protective colloid to solubilize the formed zirconium quercetin oxalate ternary complex. The molar absorptivity of the 1:3:1 (zirconium–quercetin–oxalate) complex is 7.31 × 104 L·mol−1 cm−1 at 430 nm with a stability constant of 8.2 × 1020 and its detection limit is 0.16 mg/L. Beer’s law is rectilinear up to 1.46 mg/L of zirconium (IV). The sensitivity index is 1.25 ng cm−2. The reaction of aluminium (III) with quercetin in presence of PVP as a surfactant has been studied spectrophotometrically. The molar absorptivity of the 1:3 (aluminium–quercetin) complex is 8.09 × 104 × L·mol−1·cm−1 at 433 nm, its stability constant is 2.6 × 1013 with sensitivity index of 0.33 ng·cm−2 and its detection limit is 0.08 mg/L. The optimal conditions for the quantitative determination of zirconium and aluminium were studied. The proposed methods are examined by statistical analysis of the experimental data. The methods are free from interference of most cations and anions. The proposed methods have been used to determine zirconium and aluminium in industrial waste water. [ABSTRACT FROM AUTHOR]

This article reports a study investigating the biting prevalence and malaria transmission patterns of Anopheles species in Papua New Guinea. This study was conducted on the northwestern coast of the Papua New Guinea, where malaria is highly endemic. Primary aims of the study were to establish typical annual vector biting patterns, and the basic parameters for determining the expected pattern of malaria transmission by each of the vector species. The man-biting rate of the vector species encountered was estimated through a multi-stage sampling procedure. This procedure was adopted in preference to the collection of daytime indoor-resting mosquitoes using the pyrethrin space-spray technique. It was revealed that, as elsewhere in Papua New Guinea, Anopheles farauti, An. punctulatus and An. koliensis occur throughout the area, and sporozoite-poeitive specimens were found in all three species.

Copyright of Microchimica Acta is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta physica Academiae Scientiarum Hungaricae is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose: To investigate kinematic adaptations from self-selected to fast speed walking in ASD patients., Methods: 115 primary ASD and 66 controls underwent biplanar radiographic X-rays and 3D gait analysis to calculate trunk, segmental spine and lower limb kinematics during self-selected and fast speed walking. Kinematic adaptation was calculated as the difference (Δ) between fast and self-selected speed walking. ASD with 7 or more limited kinematic adaptation parameters were classified as ASD-limited-KA, while those with less than 7 limited kinematic adaptation parameters were classified as ASD-mild-KA., Results: 25 patients were classified as ASD-limited-KA and 90 as ASD-mild-KA. ASD-limited-KA patients walked with a lesser increase of pelvic rotation (Δ = 1.7 vs 5.5°), sagittal hip movement (Δ = 3.1 vs 7.4°) and shoulder-pelvis axial rotation (Δ = 3.4 vs 6.4°) compared to controls (all p < 0.05). ASD-limited-KA had an increased SVA (60.6 vs - 5.7 mm), PT (23.7 vs 11.9°), PI-LL (9.7 vs - 11.7°), knee flexion (9.2 vs - 0.4°) and a decreased LL (44.0 vs 61.4°) compared to controls (all p < 0.05). Kinematic and radiographic alterations were less pronounced in ASD-mild-KA. The limited increase of walking speed was correlated to the deteriorated physical component summary score of SF-36 (r = 0.37)., Discussion: Kinematic limitations during adaptation from self-selected to fast speed walking highlight an alteration of a daily life activity in ASD patients. ASD with limited kinematic adaptations showed more severe sagittal malalignment with an increased SVA, PT, PI-LL, and knee flexion, a decreased LL and the most deteriorated quality of life. This highlights the importance of 3D movement analysis in the evaluation of ASD., (© 2024. The Author(s), under exclusive licence to Scoliosis Research Society.)