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The aim of this study is to investigate the microstructural, mechanical, and electrochemical characteristics of as cast Ti 7Mo 8Nb alloy, compared with the as sintered Ti 7Mo 8Nb alloy. The microstructural examination of as-cast specimen revealed an occurrence of fine and coarse acicular needles; however, the as-sintered alloy exhibited a Widmanstätten alpha structure within equiaxed beta grains and acicular alpha phase. In terms of mechanical characteristics, the as-sintered alloy showed superior yield strength and hardness measuring 1260 MPa and 380 ± 20 HV, respectively compared to the as cast alloy of 1200 MPa yield strength and 340 ± 25 HV hardness. The elastic modulus of as cast alloy was (49.2 GPa) which was higher than that of the as sintered alloy (44.9 GPa). Experiments involving wear tests have demonstrated a decrease in wear rate for the as-sintered alloy. The corrosion investigations revealed that as-sintered alloy showed better corrosion resistance compared with the as-cast alloy. The aforementioned assertion finds substantiation in empirical data indicating decreased corrosion and passivation current densities, an elevated negative phase angle reaching approximately 80°, an augmented impedance modulus, and an expanded Nyquist semicircle diameter for the alloy in its as-sintered state. These enhanced corrosion properties indicate that the as-sintered alloy possesses a surface with more stable passive film. The results of EIS analysis, using an equivalent circuit, suggest that the dual oxide layer comprises a dense base passive film and an outer porous layer. The optimum combination of high strength, unique corrosion resistance, and low elastic modulus make the as-sintered alloy a highly promising material for use in orthopedic biomedical applications.

We extend our recently developed sparse-stochastic fragmented exchange formalism for ground-state near-gap hybrid DFT to calculate absorption spectra within linear-response time-dependent generalized Kohn–Sham DFT (LR-GKS-TDDFT) for systems consisting of thousands of valence electrons within a grid-based/plane-wave representation. A mixed deterministic/fragmented-stochastic compression of the exchange kernel, here using long-range explicit exchange functionals, provides an efficient method for accurate optical spectra. Both real-time propagation as well as frequency-resolved Casida-equation-type approaches for spectra are presented, and the method is applied to large molecular dyes.

The investigated cast Ni50–Ti50 shape memory alloy was prepared using a vacuum arc furnace. The cast samples were subjected to in-vitro biocompatibility studies according to ISO 10993-12:2004, and compared to other samples Ni–Ti orthodontic wires commercially available at the dental market. The cast samples were hydroxyapatite-coated using the electrodeposition technique. The effect of surface treatment on the coating quality was addressed. The hydroxyapatite-coated samples were investigated using electrochemical impedance (EIS) and potentiodynamic techniques. Coated samples were also examined using a scanning electron microscope to inspect the coating morphology. Cytotoxicity tests on MG63 and H9C2 cell lines showed the safety and biocompatibility of the cast NiTi alloy, with a direct relationship between the incubation period of the tested samples and cell viability. Well-adhered hydroxyapatite coating was obtained on the surface-treated NiTi samples using the electrodeposition technique. EDS analysis showed a hydroxyapatite coating having a calcium to phosphorus ratio close to that of the natural bone. Electrochemical tests indicated that the highest corrosion resistance was obtained for the uncoated samples followed by the anodized sample and finally the hydroxyapatite-coated samples due to their high porosity.

Effect of ultrasonic vibration (USV) treatment on microstructure and mechanical properties of brass alloy has been investigated. Microstructure of the investigated brass alloy without USV treatment exhibited stretched and dendritic α-phase within an average length of 165 µm and also interdendritic coarse β-phase. By applying USV treatment, the α-phase is significantly refined that obtained an average length of 21 µm. In addition, USV treatment achieved more homogenized structure of αand β-phases. The refinement of microstructure enhanced of course the mechanical properties of the brass alloy including yield strength, ultimate tensile strength, elongation, hardness and wear resistance. Furthermore, fracture surfaces and worn surfaces mechanisms were also discussed.

Palladium selenides, relatively unexplored platinum group metal chalcogenides, have been attracting significant interest due to their versatility in different applications and their numerous stable phases with different crystal structures. Most vapor-based bottom-up growth approaches using furnaces have resulted in the layered PdSe2phase due to the reactions occurring in a saturated chalcogen vapor environment, in which PdSe2is the most stable phase. Here, we show that precise control over the Pd/Se stoichiometry can be achieved through tuning the chalcogen flux, both incoming and outgoing, resulting in control over the local Se concentration on the growth substrate. Increasing temperatures are used to increase the outgoing flux of Se, leading to a phase transition from PdSe2to Pd17Se15. Increasing the incoming flux of Se, through high mass loading, is then used to tune the reaction back to the growth of the PdSe2phase. Detailed material characterization is performed to prove the different crystal structures and show the ability to tailor the Pd/Se family across two stable phases, with one being layered (PdSe2) and the other being three-dimensional (3D) bulk (Pd17Se15). Finally, we demonstrate the lifecycle of phase tuning by transforming PdSe2into Pd17Se15and then back again, through control of temperature and Se mass loading. These results open pathways for exploring the solid-state properties of this family of Pd–Se materials in optoelectronics and catalysis, which have been limited to date for vapor-based furnace growth approaches on substrates.

In this study, microstructure and mechanical properties of thin wall austempered and intercritically austempered ductile iron with a chemical composition of 3.37%C, 2.7%Si, 0.30%Mn, 0.01%S, 0.01%P, 0.47%Cu, and 0.0371%Mg were investigated. Thin ductile iron samples with different thicknesses of 5, 10, and 15 mm were cast and then heat treated with two different austempering techniques. The first sample was austenitizing below upper critical temperature at 810 °C for an hour and then rapidly quenched in a salt bath at 375 °C and held for 1 h (IADI). The second treatment was carried out at austenitizing temperature of 900 °C, which was above upper critical temperature, for an hour and then rapidly quenched in a salt bath at 375 °C for 1 h (ADI). The mechanical properties of the austempered and intercritically austempered thin wall samples were evaluated and compared to the as-cast samples. The fatigue properties of all samples were simulated using ANSYS software, and the best condition was experimentally tested using plane bending fatigue testing machine. Maximum ultimate strength (1056) MPa and hardness (396 HV) were obtained for 5 mm ADI sample. Maximum impact toughness (43 J) was achieved for 15 mm IADI sample due to existing proeutectoid ferrite in matrix. Maximum simulated fatigue strength (435 MPa) was reported for 5-mm ADI sample and minimum simulated fatigue strength (160 MPa) was registered for as-cast DI sample. For both ADI and IADI castings, fatigue strength decreased with increasing sample thickness. For 10-mm ADI sample, the simulated fatigue strength was (407 MPa) which was close to the experimental result (417 MPa).

Two-dimensional (2D) materials form heterostructures in both the lateral and vertical directions when two different materials are interfaced, but with totally different bonding mechanisms of covalent in-plane to van der Waal’s layered interactions. Understanding how the competition between lateral and vertical forces influences the epitaxial growth is important for future materials development of complex mixed layered heterostructures. Here, we use atomic-resolution annular dark-field scanning transmission electron microscopy to study the detailed atomic arrangements at mixed 2D heterostructure interfaces composed of two semiconductors with distinctly different crystal symmetry and elemental composition, Pd2Se3:MoS2, in order to understand the role of different chemical bonds on the resultant epitaxy. Pd2Se3is grown off the step edge in bilayer MoS2, and the vertical and lateral epitaxial relationships of the Pd2Se3–MoS2heterostructures are investigated. We find that the similarity of geometry at the interface with one metal (Pd or Mo) atoms bonded with two chalcogens (S or Se) are the crucial factors to make the atomically stitched lateral junction of 2D heterostructures. In addition, the vertical van der Waal interactions that are normally dominant in layered materials can be overcome by in-plane forces if the interfacial atomic stitching is high in quality and low in defect density. This knowledge should help guide the approaches for improving the epitaxy in mixed 2D heterostructures and seamless stitching of in-plane 2D heterostructures with various complex monolayer structures.

Static and fatigue characteristics of Ti–6Al–3Mo–2Zr–2Sn–2Nb–1.5Cr–0.1Si (TC21 Ti-alloy) in as-received and heat-treated conditions were investigated at ambient temperature. Two solution treatment cycles were applied on as-received TC21 samples. The first treatment was done below β-transus temperature (Tβ) at 920 °C/15 min and the second one above β-transus temperature (Tβ) at 1020 °C/15 min followed by water quenching. Both groups of samples were aged at 600 °C for 4 h before being air-cooled. The treated samples at 920 °C showed an equiaxed α + βstructure. However, a complete martensitic structure was obtained in the treated samples at 1020 °C. In addition, secondary α-platelets (αs) precipitated inside retained β-phase (βr) due to aging process. The treated samples at 920 °C revealed the best tensile properties (tensile strength, 1447 MPa, and elongation, 8%). Theoretical study using Solidworks simulation program showed a fatigue limit of 709 MPa for as-received smooth samples. The treated samples at 920 °C obtained the highest fatigue limit of 866.5 MPa. However, the treated samples at 1020 °C revealed the lowest fatigue limit of 598.5 MPa. The as-received notched samples recorded a fatigue limit of 392 MPa by a decrease in the fatigue limit of about 45% compared with the as-received smooth samples. The experimental study using rotary bending fatigue machine recorded the best fatigue limit of 782.5 MPa for treated samples at 920 °C. As-received and treated samples at 1020 °C achieved fatigue limits of 651 and 546 MPa, respectively. The as-received notched samples showed a reduction in fatigue limit by approximately 43% from 625 to 359 MPa. Hence, the treated samples at 920 °C showed the best fatigue properties. The difference between theoretical and experimental fatigue values was less than 10% in four studied conditions.

A resonant microcantilever sensor is fabricated from a zinc oxide (ZnO) thin film, which serves as both the structural and sensing layers. An open-air spatial atomic layer deposition technique is used to deposit the ZnO layer to achieve a ∼200 nm thickness, an order of magnitude lower than the thicknesses of conventional microcantilever sensors. The reduction in the number of layers, in the cantilever dimensions, and its overall lower mass lead to an ultrahigh sensitivity, demonstrated by detection of low humidity levels. A maximum sensitivity of 23649 ppm/% RH at 5.8% RH is observed, which is several orders of magnitude larger than those reported for other resonant humidity sensors. Furthermore, the ZnO cantilever sensor is self-actuated in air, an advantageous detection mode that enables simpler and lower-power-consumption sensors.

This study is a trial to understand the effect of alloying elements variation and solution heat treatment conditions on the microstructure and its turn on the mechanical properties and corrosion resistance of Fe–Mn–Al–Cr–C stainless steel system. Steels under investigation are melted and produced utilizing the vacuum arc melting technique. Furthermore, cast alloys were solution heat-treated at 1050 °C for 2 and 4 h, followed by water quenching. Light and field emission scanning electron microscope, FESEM, in addition to x-ray diffraction were used to study the different microstructural characteristics of the produced steel. Hardness and weight loss were measured to evaluate the wear properties of the studied steels. Additionally, the corrosion resistance of these designed selected Fe–Mn–Al–Cr–C stainless steels was examined. The experimental results show that the microstructure of the cast steel consists of numerous phases such as austenite, ferrite, martensite as well as carbide precipitates. The latter carbides solidify either in the form of blocky or lamellar; (Fe, Mn, Cr)3C. On the other hand, in the case of the solution-treated steel, the microstructure consists of an austenite matrix with a lower volume fraction (Vf) of carbides. As the carbon, manganese, and chromium content increases, the Vf of the precipitated carbides increase, which in turn enhances the hardness and wear properties of the studied steels. The solution treatment process dissolves and lowers the percentage of carbides found in the microstructure of cast steels. The solutionized heat-treated steels containing high Mn and Al contents in addition to a moderate amount of Cr show the best hardness, wear and corrosion resistance among the other studied steels.

This paper has attempted to investigate microstructure evolution as a function of silicon content using Thermo-Calc software as a computational prediction technique. This research work aims to evaluate the mechanical properties of investigated steel and outline their relationship with the microstructure.Thermo-Calc was used for calculating phase volume fractions of a set of silicon-containing steel alloys. The mechanical properties of investigated steels such as tensile properties, hardness, and impact toughness) were evaluated from a microstructure point of view. The fracture surface of tensile samples was studied utilizing a scanning electron microscope equipped with energy-dispersive x-ray (point micro-analysis). The experimental results revealed that microstructure evaluations were close to the predicted computational by Thermo-Calc software. Also, the results showed that the microstructure of the high silicon steel (≥ 1.5 wt.%) is more dense, well homogenous and contains a volume fraction of 93% Bcc-ferrite at approximately, and 1.5% Fcc-austenite, as well as 5.5% different types of carbides. Also, The experimental results showed that the mechanical properties of the steel containing silicon (1.59 wt.%) have a remarkable enhancement of toughness in combination with high hardness and tensile strength compared to low silicon steel. The yield strength (1088 MPa) and elongation (16.4%) were obtained for austempered steel containing 1.59 wt.% silicon. The fracture surface mode of the investigated steel transition from brittle to ductile fracture according to the silicon content related to obtained microstructure.

The objective of this paper is to enhance service life of excavator bucket teeth for decreasing the idle time required to reinstate the teeth periodically during excavation process. To achieve this goal, medium-carbon steel was chosen with a chemical composition of 0.41C, 0.23Si, 0.75Mn, 1.0Cr, 0.23Mo (wt.%) to cast as Y-blocks with wall thickness of 30 mm using medium-frequency induction furnace. Optimum tensile strength (1492 MPa) and hardness (474 HV) were obtained for the sample quenched at 220 °C. Optimum impact toughness (17 J) was reported for the samples quenched at 270 °C compared to the as-cast sample (9 J) and quenched one at 220 °C (14 J). The lowest wear rate was shown for the quenched sample at 220 °C compared to the as-cast and quenched sample at 270 °C. The best combination of wear resistance, hardness, impact toughness and tensile properties was achieved for the quenched sample at 220 °C.

A novel process to synthesize plasmonic MoO3–Xnanosheets is demonstrated, in which MoS2powders suspended in ethanol/water are irradiated with pulses from a femtosecond laser, resulting in simultaneous Coulomb explosion, photoexfoliation, and oxidation. The oxidation process is found to start with the formation of hydrogen-bonded molybdenum oxide (HXMoO3), followed by the release of −OH2groups to create oxygen vacancies, and finally, MoO3–Xis oxidized to MoO3after extended irradiation. The formation of HXMoO3is the critical step to create enough oxygen vacancies for localized surface plasmon resonance (LSPR), and this step is attributed to H3+dissociated from ethanol under femtosecond laser irradiation. It is found that 80–90% ethanol is the optimal concentration to synthesize plasmonic MoO3–X, where the balance of water facilitates the release of the −OH2groups to create the required vacancies. It is shown that different organic solvents like methanol, 1-propanol, and isopropyl alcohol that were reported to generate large amounts of H3+under femtosecond laser irradiation can also oxidize MoS2into plasmonic MoO3–X. The LSPR properties of the synthesized MoO3–Xare evaluated by UV–vis spectroscopy and photothermal conversion measurements. A photothermal conversion efficiency of 33% is observed under near-infrared irradiation, suggesting a potential application in photothermal cancer therapy.

Abstract: The effect of strain hardening and aging processes on microstructure, tensile and fatigue properties was investigated on cast TC21 samples with a chemical composition of Ti-6.1Al-2.96Mo-2.11Nb-1.98Sn-2.05Zr-1.44Cr-0.1Si. Plastic deformation (strain hardening) was applied on swaged samples at room temperature with 2%, 3% and 4% strain. By applying aging process at 575°C for 4 hr, secondary α-platelets were precipitated in the transformed β-phase. Maximum hardness (HV440) was achieved for 4%def. + aged samples. However, minimum hardness (HV323) was recorded for aged samples. Maximum ultimate tensile strength (1311MPa) and elongation (14%) were obtained for 4% def. + aged samples due to presence of high amount of dislocation density as well as precipitation of secondary α-platelets in the residual β-phase. Minimum ultimate tensile strength (1020MPa) and elongation (3%) were reported for as-cast samples. Theoretical study using ANSYS software program was carried out for estimating fatigue limits for investigated samples. For validating the theoretical results, experimental test was done using rotating bending fatigue testing machine on three selected conditions of swaged, 2%def. + aged and 4%def. + aged. Maximum estimated fatigue strength of 775 MPa was obtained for 4%def. + aged samples, and the experimental one was 755 MPa. Hence, the difference between estimated and experimental fatigue limits for 4%def. + aged samples was less than of 3%. Graphical Abstract:

In the present research work on TC21 titanium alloy (6.5Al−3Mo−1.9Nb−2.2Sn−2.2Zr−1.5Cr), the effects of cold deformation, solution treatment with different cooling rates and then aging on microstructure, hardness and wear property were investigated. A cold deformation at room temperature with 15% reduction in height was applied on annealed samples. The samples were solution-treated at 920 °C for 15 min followed by different cooling rates of water quenching (WQ), air cooling (AC) and furnace cooling (FC) to room temperature. Finally, the samples were aged at 590 °C for 4 h. Secondary α-platelets precipitated in residual β-phase in the case of solution-treated samples with AC condition and aged ones. The maximum hardness of HV 470 was obtained for WQ + aging condition due to the presence of high amount of residual β-matrix (69%), while the minimum hardness of HV 328 was reported for FC condition. Aging process after solution treatment can considerably enhance the wear property and this enhancement can reach up to about 122% by applying aging after WQ compared with the annealed samples.

TC21 with a composition of Ti-6Al-3Mo-1.9Nb-2.2Sn-2.2Zr-1.5Cr is considered a new titanium alloy that is used in aerospace applications as a replacement for the famous Ti-6Al-4V alloy due to its high strength-to-weight ratio, high operating temperature and corrosion resistance. In this study, two different solution treatment techniques were applied on TC21 samples. Solution treatment was applied using two step heating at 1000/800 °C for 15 min each and then cooled using water quenching or air cooling to see the effect of cooling rate on microstructure as well as mechanical properties. The solution treated samples were divided into two groups; one was tested as solution treated samples without aging. While, the second group was aged at 575 °C for 4 hrs. Maximum hardness of 442 HV was observed for the water quenched and aged samples, while the minimum hardness of 340 HV was obtained for water quenched samples without aging. The lowest wear rate was obtained for water quenched and aged samples. However, the highest wear rate was reported for the samples solution treated and water quenched without aging.

Over the last decade, technologies derived from convolutional neural networks (CNNs) called Deep Learning applications, have revolutionized fields as diverse as cancer detection, self-driving cars, virtual assistants, etc. However, many users of such applications are not experts in Machine Learning itself. Consequently, there is limited knowledge among the community to run such applications in an optimized manner. The performance question for Deep Learning applications has typically been addressed by employing bespoke hardware (e.g., GPUs) better suited for such compute-intensive operations. However, such a degree of performance is only accessibly at increasingly high financial costs leaving only big corporations and governments with resources sufficient enough to employ them at a large scale. As a result, an average user is only left with access to commodity clusters with, in many cases, only CPUs as the sole processing element. For such users to make effective use of resources at their disposal, concerted efforts are necessary to figure out optimal hardware and software configurations. This study is one such step in this direction as we use the Roofline model to perform a systematic analysis of representative CNN models and identify opportunities for black box and application-aware optimizations. Using the findings from our study, we are able to obtain up to 3.5×speedup compared to vanilla TensorFlow with default configurations.

Calculations of excited states in the Green’s function formalism often invokes the diagonal approximation, in which the quasiparticle states are taken from a mean-field calculation. In this paper, we extend the stochastic approaches applied in the many-body perturbation theory and overcome this limitation for large systems in which we are interested in a small subset of states. We separate the problem into a core subspace whose coupling to the remainder of the system environment is stochastically sampled. This method is exemplified on computing hole injection energies into CO2on an extended gold surface with nearly 3000 electrons. We find that in the extended system the size of the problem can be compressed up to 95% using stochastic sampling. This result provides a way forward for self-consistent stochastic methods and determination of Dyson orbitals in large systems.

We present a new velocity-gauge real-time, time-dependent density functional tight-binding (VG-rtTDDFTB) implementation in the open-source DFTB+ software package (https://dftbplus.org) for probing electronic excitations in large, condensed matter systems. Our VG-rtTDDFTB approach enables real-time electron dynamics simulations of large, periodic, condensed matter systems containing thousands of atoms with a favorable computational scaling as a function of system size. We provide computational details and benchmark calculations to demonstrate its accuracy and computational parallelizability on a variety of large material systems. As a representative example, we calculate laser-induced electron dynamics in a 512-atom amorphous silicon supercell to highlight the large periodic systems that can be examined with our implementation. Taken together, our VG-rtTDDFTB approach enables new electron dynamics simulations of complex systems that require large periodic supercells, such as crystal defects, complex surfaces, nanowires, and amorphous materials.

Purpose -- Hyper-heuristics are a class of high-level search techniques which operate on a search space of heuristics rather than directly on a search space of solutions. The purpose of this paper is to investigate the suitability of using genetic programming as a hyper-heuristic methodology to generate constructive heuristics to solve the multidimensional 0-1 knapsack problem Design/methodology/approach -- Early hyper-heuristics focused on selecting and applying a low-level heuristic at each stage of a search. Recent trends in hyper-heuristic research have led to a number of approaches being developed to automatically generate new heuristics from a set of heuristic components. A population of heuristics to rank knapsack items are trained on a subset of test problems and then applied to unseen instances. Findings -- The results over a set of standard benchmarks show that genetic programming can be used to generate constructive heuristics which yield human-competitive results. Originality/value -- In this work the authors show that genetic programming is suitable as a method to generate reusable constructive heuristics for the multidimensional 0-1 knapsack problem. This is classified as a hyper-heuristic approach as it operates on a search space of heuristics rather than a search space of solutions. To our knowledge, this is the first time in the literature a GP hyper-heuristic has been used to solve the multidimensional 0-1 knapsack problem. The results suggest that using GP to evolve ranking mechanisms merits further future research effort. [ABSTRACT FROM AUTHOR]

α+βtitanium alloy with a composition of Ti–6.55Al–3.41Mo–1.77Zr (mass fraction, %) was cast into bars in a graphite mould using vacuum induction skull melting furnace (ISM). The cast bars were hot swaged at 700 °C and then heat treated by two different regimes which resulted in fine and coarse lamella structures, respectively. The grain size of the as-cast structure was estimated to be 660 μm and the swaged samples obtained a very fine grain size in the range of 50 μm. The overall best combination of hardness, tensile properties, and wear resistance of the α+βtitanium alloy was achieved by heat treating the samples at 1050 °C for getting fine lamellar structure. The maximum compression strength was reported for the heat treated samples at 800 °C with coarse lamella structure. The minimum wear rate was reported for the heat treated samples with fine lamellar structure and the maximum wear rate was obtained for as-cast samples due to its coarse and heterogeneity microstructure.

Incidence of various Hodgkin (HL) and non-Hodgkin lymphoma (NHL) subtypes and association with viruses in Lebanon are not known. We undertook a nationwide study of 272 patients diagnosed with lymphoma in 2007. HL comprised 32.7 % (n= 89) of cases while NHL represented 67.3 % (n= 183). Consistent with the literature, nodular sclerosis was the most predominant HL subtype (n= 57/89). Among NHL, B-cell NHL represented 88 % (n= 161/183), T-cell NHL 9 % (n= 17/183), whereas in 2.7 % it was not classifiable. The B-cell NHL comprised predominantly diffuse large B-cell lymphoma (46 %) and follicular lymphoma (23 %). 81 cases were reviewed by a panel of pathologists with 87.6 % concordance rate. Serology was negative for hepatitis C in 122 tested cases. HIV was positive in 2 cases. Two adult T-cell leukemia/lymphoma were HTLV-I positive. EBV IgG were positive in 88.5 % of cases. 38 EBV seropositive cases [27 NHL (24 B-cell, 3 T-cell) and 11 HL] were studied for EBV genome expression using EBV-encoded RNA (EBER)-in situ hybridization. EBER expression was positive in 8 (21 %) cases (6 HL, 2 T-cell NHL). The distribution of lymphoma subtypes in Lebanon appears similar to that of Western countries. The high rate of EBV positivity in HL and T-cell lymphoma by EBER deserves further investigation.

Recycled commercially pure Ti having different Fe and O contents was rotary swaged at 700°C in order to break down the coarse as-cast microstructures. After swaging, materials were annealed at various temperatures to study potential coarsening of the recrystallized a-grains. While marked grain growth occurred in material A with low Fe and O contents after annealing for 1 hour at temperatures as low as 500°C, the grain size in material B with higher Fe and O contents hardly increased even after a 1 hour exposure at temperatures as high as 800°C. Yield stress, tensile strengformatth and high cycle fatigue strength in both as-cast and annealed conditions of material B were significantly higher than in the corresponding conditions of material A, presumably owing to more marked solid solution hardening and fine grain size strengthening of material B. In addition, precipitation hardening by fine Fe containing oxide particles may also contribute to the higher strength level of material B. Shot peening and roller-burnishing were found to drastically enhance the high cycle fatigue strengths relative to the electrolytically polished baseline conditions.

This research studies the effect of dynamic solidification, niobium addition, and their combined action on the as-cast structure and mechanical properties of hypoeutectic 15% Cr-2% Mo white cast irons containing 2.5% C. The effect of heat treatment at different tempering temperatures was also studied. Investigations were performed by means of image analysis, scanning electron microscopy, and X-ray diffraction. Abrasion resistance and impact toughness tests were performed. Fracture and worn surfaces were studied. Results show that optimized abrasion resistance and impact toughness can be achieved in a homogeneous microstructure consisting of hard, fine, and non-interconnected carbides in a matrix that has a high fraction of metastable austenite.

To determine the risk factors and rate of 30-day operative mortality among Jordanian patients undergoing isolated coronary artery bypass surgery, we reviewed the records (January, 2005 to July, 2009) of 1,046 consecutive patients. Demographic and perioperative data were analyzed by univariate and multivariate analysis. The 30-day operative mortality rate was 5.9%. Significant independent predictors of death were age >65 years, female sex, heart failure, ejection fraction ≤35%, prolonged inotropic support, mechanical ventilation >12 h, postoperative pneumonia, and postoperative stroke. The 30-day operative mortality rate was comparable to that reported in other countries.

This work analyses the wear behaviour and impact toughness of high Cr –Mo white irons alloyed with titanium as related to their microstructure and solidification path. Five alloys were used with different percentages of titanium (0, 0.47, 0.932, 1.31 and 1.78 %). Such additions of titanium resulted in precipitation of small hard TiC particles in the austenitic matrix. These particles were well distributed in the matrix with Ti-additions up to 1.31% and then started to agglomerate with 1.78%Ti. Hardness increased dramatically with increasing amount of titanium addition. The wear behaviour was investigated for each alloy in the as-cast condition using the pin-on-ring configuration for 30 min against a ring made of SiC that rotated at a constant speed of 65 rpm. The wear test was performed under a load range of 30–180 N. The results are discussed in terms of microstructure and the minimum wear rate was obtained for the white cast iron alloyed with 1.31% titanium. The optimum tensile strength, impact toughness and wear resistance were also observed for the iron alloyed with 1.31% titanium. However, these properties started to deteriorate with further increase in titanium addition due to the clustering effect of titanium carbide particles in the austenitic matrix. Therefore, the optimum wear resistance and impact toughness of white cast iron under investigation (16% Cr-1.3% Mo-2.3% Ni) can be achieved by adding 1.31% titanium.

First results of the influence of Equal Channel Angular Pressing (ECAP) on the wear behavior of the magnesium alloy AZ80 have been discussed. The evident grain refinement and redistribution of second phases in the 4 pass processed materials resulted in an increase of the hardness state in the AZ80 alloy. Wear tests conducted on a pin-on-disc set-up revealed better wear resistance for the 4 pass processed materials. Isothermal aging treatment, at 210°C for 10 hrs, of the ECAP processed materials showed that wear resistance properties are improved markedly. For incremental sliding speeds during the wear test, wear rate of the AZ80 alloy was found to increase.

This research aims at studying the structural refinement of 15%Cr-2%Mo hypo- and hypereutectic white irons through dynamic solidification and Nb-alloying (1-2%Nb). Solidification behavior was studied using DSC. Microstructure investigation and analysis were performed using optical, image analyzer as well as SEM, EDX and XRD analysis. Refinement mechanisms proposed involved both enhancing nucleation and altering the growth process of the primary and eutectic phases either by fragmentation of the primary growing phase in the case of dynamic solidification or by consuming the available carbon from the liquid and hence the amount and size of M7C3 will decrease in the case of addition of Nb-alloying. Nb has higher affinity to carbon during solidification, higher formation temperature than the main microstructure constituents and forms fine carbide so Nb achieves refinement of the microstructure.

Cytomegalovirus (CMV) infection is a major infectious complication post-allogeneic hematopoietic stem cell transplantation (HSCT). CMV seropositivity in Eastern Mediterranean and certain Asian countries is reported to be close to 100%; hence, the need for effective pre-emptive treatment strategy that has low toxicity. Valganciclovir (VGC) is a prodrug of ganciclovir with high bioavailability.

The effect of carbide morphology and matrix structure on abrasion resistance of cast alloyed steel with 2.57% C, 16.2% Cr and 0.78% Mo was studied in the as‐cast and heat treated conditions. Samples were austenitized at three different temperatures of 980, 1050 and 1250 °C for 15 minutes and followed by tempering at 540 °C for 3 hours. The austenitizing temperature of 980 °C revealed fully martensitic structure with little amount of retained austenite, while at 1050 °C the matrix was austenitic with massive amount of coarse secondary carbides. The austenitic matrix with very fine secondary carbides was developed at 1250 °C. The maximum abrasion resistance was obtained at 1050 °C due to the highest structure hardness and existence of both eutectic and secondary carbides in larger size than the formed groove by the abrasive particles during the wear test. On the other hand, the as‐cast pearlitic structure showed high wear rate by an applied load of up to 0.2 bar, followed by very rapid increase in wear rate with higher applied loads. It could be considered that the austenitizing temperature of 1050 °C showed better combination of abrasion resistance and toughness in comparison with other heat treatment cycles.

AbstractObjective:To analyze the ocular findings in aplastic anemia. Design:Eighteen patients with aplastic anemia were examined. Results:Ocular findings included cotton wool spots (38%), nerve fiber layer or preretinal hemorrhages (67%), vitreous hemorrhages (13%), a picture resembling central retinal vein occlusion (13%) and optic disk edema (6%). Preretinal hemorrhages were the presenting sign of aplastic anemia in 2 patients (13%). Conclusions:A blood profile is needed in patients with unexplained retinal hemorrhages. Patients with aplastic anemia need to avoid ocular massage and Valsalva maneuvers to decrease ocular morbidity.Copyright © 2000 S. Karger AG, Basel

The present study aims to determine the relative contribution of psychological flow and resilience in anticipating the cognitive failure among elementary school students. The sample consisted of (114) male and female students aged between 13 and 15 years. The descriptive method was adopted. The study employed and designed the following tools: the psychological flow scale, the psychological resilience scale, and the cognitive failure scale. The psychometric properties of these tools were checked. The results showed that the level of psychological flow among the participants is high, the level of psychological resilience among the sample is high, and the level of cognitive failure among the participants is low. The results also concluded that the psychological flow is suitable for predicting cognitive failure, as the regression coefficient was −7.436, which is a statistically significant value at the level 0.001; and the psychological resilience can be used in predicting cognitive failure, as the regression coefficient was −5.824, and it is a statistically significant value at the level 0.001. The study has a number of recommendations: designing training programs to develop the psychological flow of learners at all learning stages, holding seminars and workshops aimed at educating learners about the importance of psychological resilience for their enjoyment of normal mental health, and raising the awareness among the officials at the Ministry of Education about the need to train students on cognitive strategies that help reduce the level of cognitive failure.

In an attempt to improve the quality of the agricultural drain in Egypt for its reuse again in the irrigation, low-cost solution such as sand filter along with/without other filtration media has been used in this research. As a result of that, pilot plant of sand filter mixed with other filtration media was tested for its ability to improve the sand performance in removing the suspended solids and organic matters from agricultural drain water of the Belbeis drain (in Sharkia governorate in Egypt). Sand only, sand mixed with sponge, sand mixed with activated carbon and sand mixed with ceramic cylinders have been tested to find the best media combination and optimum mixing sand/ medium ratio and optimum infiltration rate. The work has been done on four runs. It was found that sand mixed with ceramic cylinders gave the best removal efficiency with respect to total chemical oxygen demand and chemical oxygen demand for solution which were 77, 74%, respectively, whereas sand mixed with sponge had the best removal efficiency with respect to total suspended solids which was 89%. Also, all tested media combination had effluent quality that complied with Egyptian law 48 for the year 1982 regarding the disposal of wastewater into agricultural drains (chemical oxygen demand ≤ 80 mg/l, total suspended solids ≤ 50 mg/l).

No relevant conflicts of interest to declare.

lymphoid neoplasms represent a diverse group of neoplasms that are broadly classified into non-Hodgkin lymphomas (NHL) and Hodgkin lymphoma (HL). Incidence of particular subtypes and pathogenic associations with certain viral infections are derived from data from the Western world. Little is known about such associations in developing countries; accordingly, this prospective study evaluates newly diagnosed cases of lymphomas in Lebanon and evaluates the incidence of particular subtypes and possible association with various viral infections.this was a collaborative nationwide study that included all patients diagnosed with lymphoma in Lebanon in 2007. Epidemiological, clinical and histological data were collected. Available lymphoma tissue (stained slides and paraffin-embedded tissue) was reviewed by a panel of pathologists. Blood was collected for serologic testing for the following viruses: hepatitis C (HCV), HIV, EBV, and HTLV-I.275 cases, 140 (50.7%) males and 136 (49.3%), with lymphoma were diagnosed. Eighty one cases (76 from academic centers and 5 from community hospitals) were reviewed by the pathology panel. The overall concordance rate was 87.6% (71/81); there was discordance in 6 (7.4%) cases: 3 originally diagnosed as diffuse large B cell lymphoma (DLBCL) were revised to high-grade follicular lymphomas, 1 small lymphocytic lymphoma (SLL) previously DLBCL, 1 DLBCL previously low grade lymphoma, 1 DLBCL previously lymphoblastic lymphoma; 4 cases were considered equivocal on revision. The enrolled cases were classified as follows: 183(66.5%) NHL (150 cases B cell lymphoma - 81 DLBCL, 35 follicular, 12 marginal zone/MALT, 11 mantle cell, 7 SLL/CLL, 2 transformed follicular/DLBCL, 2 lymphoblastic; 16 cases T cell lymphoma - 7 peripheral T cell NOS, 4 anaplastic, 2 lymphoblastic, 1 angioimmunoblastic, 1 NK cell, 1 adult T cell leukemia/lymphoma (ATLL); 17 unclassified); and 92(33.5%) HL (60 nodular sclerosis, 5 mixed cellularity, 5 lymphocyte predominant, 1 lymphocyte-rich, 21 unclassified). Blood was obtained from 120 patients. Serology was negative for HCV in all tested cases. HIV was positive in 2 cases (1 NHL, 1 HL). EBV IgG were positive in 106 (88.3%) cases (68/77 NHL, 38/43 HL). Also, 38 EBV seropositive cases (27 NHL (24 B-cell type & 3 T-cell type), 11 HL) were studied for latent membrane protein-1 (LMP-1); LMP-1 staining was positive in 8(21%) cases, of which 6 were HL and 2 were T-cell NHL. Only one case with peripheral T cell lymphoma (ATLL) tested positive for HTLV-1.our epidemiological study showed that two-thirds of lymphoma cases diagnosed over a year were NHL. Reviewing almost one-third of cases showed an 87.6% concordance rate in diagnosis. Serologic testing of viruses did not reveal any specific pattern that suggests an association between the tested viruses (HCV, HIV, EBV, and HTLV-I) and lymphoma. However, LMP-1 testing was positive in 54.5% of IgG positive HL cases and in 66.7% of IgG positive T-cell NHL. These finding confirm a strong association of EBV with HL and T-cell lymphoma.Bazarbachi: Hoffman La Roche: Research Funding.

We present an open-source software package, VAN-DAMME (Versatile Approaches to Numerically Design, Accelerate, and Manipulate Magnetic Excitations), for massively-parallelized quantum optimal control (QOC) calculations of multi-qubit systems. To enable large QOC calculations, the VAN-DAMME software package utilizes symmetry-based techniques with custom GPU-enhanced algorithms. This combined approach allows for the simultaneous computation of hundreds of matrix exponential propagators that efficiently leverage the intra-GPU parallelism found in high-performance GPUs. In addition, to maximize the computational efficiency of the VAN-DAMME code, we carried out several extensive tests on data layout, computational complexity, memory requirements, and performance. These extensive analyses allowed us to develop computationally efficient approaches for evaluating complex-valued matrix exponential propagators based on Padé approximants. To assess the computational performance of our GPU-accelerated VAN-DAMME code, we carried out QOC calculations of systems containing 10 - 15 qubits, which showed that our GPU implementation is 18.4× faster than the corresponding CPU implementation. Our GPU-accelerated enhancements allow efficient calculations of multi-qubit systems, which can be used for the efficient implementation of QOC applications across multiple domains. Program Title: VAN-DAMME CPC Library link to program files:: https://doi.org/10.17632/zcgw2n5bjf.1 Licensing provisions: GNU General Public License 3 Programming language: C++ and CUDA Nature of problem: The VAN-DAMME software package utilizes GPU-accelerated routines and new algorithmic improvements to compute optimized time-dependent magnetic fields that can drive a system from a known initial qubit configuration to a specified target state with a large (≈1) transition probability. Solution method: Quantum control, GPU acceleration, analytic gradients, matrix exponential, and gradient ascent optimization.   [ABSTRACT FROM AUTHOR]

We present a new software module, QRCODE (Quantum Research for Calculating Optically Driven Excitations), for massively parallelized real-time time-dependent density functional theory (RT-TDDFT) calculations of periodic systems in the open-source Qbox software package. Our approach utilizes a custom implementation of a fast Fourier transformation scheme that significantly reduces inter-node message passing interface (MPI) communication of the major computational kernel and shows impressive scaling up to 16,344 CPU cores. In addition to improving computational performance, QRCODE contains a suite of various time propagators for accurate RT-TDDFT calculations. As benchmark applications of QRCODE, we calculate the current density and optical absorption spectra of hexagonal boron nitride (h-BN) and photo-driven reaction dynamics of the ozone-oxygen reaction. We also calculate the second and higher harmonic generation of monolayer and multi-layer boron nitride structures as examples of large material systems. Our optimized implementation of RT-TDDFT in QRCODE enables large-scale calculations of real-time electron dynamics of chemical and material systems with enhanced computational performance and impressive scaling across several thousand CPU cores. [Display omitted] [ABSTRACT FROM AUTHOR]

We present an open-source software package, TRAVOLTA (Terrific Refinements to Accelerate, Validate, and Optimize Large Time-dependent Algorithms), for carrying out massively parallelized quantum optimal control calculations on GPUs. The TRAVOLTA software package is a significant overhaul of our previous NIC-CAGE algorithm and also includes algorithmic improvements to the gradient ascent procedure to enable faster convergence. We examine three different variants of GPU parallelization to assess their performance in constructing optimal control fields in a variety of quantum systems. In addition, we provide several examples with extensive benchmarks of our GPU-enhanced TRAVOLTA code to show that it generates the same results as previous CPU-based algorithms but with a speedup that is more than ten times faster. Our GPU enhancements and algorithmic improvements enable large quantum optimal control calculations that can be efficiently and routinely executed on modern multi-core computational hardware. Program Title: TRAVOLTA CPC Library link to program files: https://doi.org/10.17632/grwppm37rn.1 Licensing provisions: GNU General Public License 3 Programming language: C++, openBLAS, and CUDA Supplementary material: Brief review of LU decomposition, raw numerical values used to generate Fig. 6 in the main text, and input examples for the TRAVOLTA software package. Nature of problem: The TRAVOLTA software package utilizes GPU accelerated routines and new algorithmic improvements to compute optimized electric fields that can drive a system from a known initial vibrational eigenstate to a specified final quantum state with a large (≈1) transition probability. Solution method: Quantum control, GPU acceleration, analytic gradients, Crank-Nicolson propagation, and gradient ascent optimization. [ABSTRACT FROM AUTHOR]