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1
Jovanović, Milan T., Višeslava Rajković, and Ivana Cvijović-Alagić. "Copper alloys with improved properties: standard ingot metallurgy vs. powder metallurgy." Metallurgical and Materials Engineering 20, no. 3 (2014): 207–16. http://dx.doi.org/10.5937/metmateng1403207j.
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Three copper-based alloys: two composites reinforced with Al2O3 particles and processed through powder metallurgy (P/M) route, i.e. by internal oxidation (Cu-2.5Al composite) and by mechanical alloying (Cu-4.7Al2O3 ) and Cu-0.4Cr-0.08Zr alloy produced by ingot metallurgy (vacuum melting and casting) were the object of this investigation. Light microscope and scanning electron microscope (SEM) equipped with electron X-ray spectrometer (EDS) were used for microstructural characterization. Microhardness and electrical conductivity were also measured. Compared to composite materials, Cu-0.4Cr-0.08Zr alloy possesses highest electrical conductivity in the range from 20 to 800 ℃, whereas the lowest conductivity shows composite Cu-2.5Al processed by internal oxidation. In spite to somewhat lower electrical conductivity (probably due to inadequate density), Cu-2.5Al composite exhibits thermal stability enabling its application at much higher temperatures than materials processed by mechanical alloying or by vacuum melting and casting.
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Widayat, W., Marcelinus Christwardana, S. Syaiful, Hantoro Satriadi, Akhmad Khaibar Khaibar, and Mukhammad Mujahid Almaki. "Development of Heterogeneous Alkali Methoxide Catalyst from Fly Ash and Limestone." Chemistry & Chemical Technology 14, no. 4 (2020): 521–30. http://dx.doi.org/10.23939/chcht14.04.521.
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This study is aimed to use fly ash and limestone as raw materials for preparing alkali methoxide heterogeneous catalysts for transesterification of palm oil into biodiesel. The heterogeneous catalyst was synthesized from fly ash and limestone through wet and dry methods and calcined within 1073–1273 K. X-ray diffraction and scanning electron microscopy analyses indicated the well-dispersed presence of the Ca(OCH3)2 crystal over the fly ash and limestone framework, which was mixed using wet method and calcined at 1073 K (W-800). Results showed that W-800 exhibited larger surface area and more uniform active sites than the other catalysts. About 88.6 % of biodiesel was produced from commercial palm oil with W-800 as the catalyst. The product possesses physicochemical characteristics, such as density, kinematic viscosity and free fatty acid content, which satisfy the international biodiesel standard. The catalyst was used for biodiesel production for four cycles, and the biodiesel yield was maintained up to 91.87 % from the initial value.
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Vargas, Reinaldo Azevedo, Rubens Chiba, Marco Andreoli та Emília Satoshi Miyamaru Seo. "Strontium Dopant Concentrations Influence on Nd1-xSrxMnO3±δ Structural and Electrical Conductivity". Materials Science Forum 660-661 (жовтень 2010): 636–40. http://dx.doi.org/10.4028/www.scientific.net/msf.660-661.636.
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Many different types of ceramic materials are currently being studied as possible cathodes in Solid Oxide Fuel Cells (SOFC), in an attempt to reduce operating temperatures. Strontium-doped neodymium manganite (Nd1-xSrxMnO3±δ) was used as an intermediate temperature solid oxide fuel cell cathode. X-ray diffraction and electrical conductivity of the Nd1-xSrxMnO3±δ system with a perovskite structure were studied in function of x equal to 0.10, 0.30 and 0.50. An orthorhombic pseudo-perovskite structure was assigned to all powder compositions prepared by standard ceramic technique. Electrical conductivity was described by the small polaron hopping conductivity model, as well as, increases due to regular increments of Sr content for all compositions. Electrical conductivity was measured at 25.2, 26.4 and 37.1Scm-1 for x = 0.10, 0.30 and 0.50, respectively at 800°C.
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Mitwalsky, A., J. Willer, and H. Oppolzer. "HRTEM observations of schottky barrier interfaces at WSi0.4/GaAs contacts." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 4 (1990): 726–27. http://dx.doi.org/10.1017/s0424820100176769.
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WSix is one of the most favored Schottky gate metallizations due to its self-aligned contact formation capability and high temperature resistance (∽800°C) for x ∽ 0.45. It will be demonstrated that fine details of the microstructure at this WSi0.4/GaAs Schottky interface change clearly when temperature is increased up to 800°C. These findings are relevant for explaining Schottky barrier measurements usually implying the existence of an intimate and uniform contact between metallization and semiconductor. Similar investigations have been performed on related WSix (x = 0.1 and 0.6) systems.The WSi0.4 Schottky contact was sputtered from a planar magnetron compound target at a power level of 4 W·cm−2 and a deposition rate of 45 nm·min−1. As described previously films were deposited in dc-mode with an rf-bias of 50 V. Initial wafer surface preparation of bulk doped GaAs (Si : 7·1016cm−3) involved standard H2SO4 etch followed by a surface etch in diluted NH4OH. The sputtering chamber was evacuated to a base pressure of 2·10−7 Torr. A heat treatment at 250°C for 10 min of the substrate was performed immediately prior to silicide deposition. The temperature stability and interface structure of this metallization was investigated by cross-sectional transmission electron microscopy (TEM) at specimens annealed for 20 min at 400°C, 720°C and 800°C, respectively. In particular, atomic scale information was attained by high-resolution TEM (HRTEM) using a 400 kV TEM with a point resolution of 0·18 nm.
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Cheng, An, Sao Jeng Chao, and Wei Ting Lin. "Effect of Calcination Temperature on Pozzolanic Reaction of Calcined Shale Mortar." Applied Mechanics and Materials 174-177 (May 2012): 843–46. http://dx.doi.org/10.4028/www.scientific.net/amm.174-177.843.
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This study investigated the influence of calcination temperature on the pozzolanic activity of shale. Calcination temperatures of 500 °C, 600 °C, 700 °C, 800 °C, and 900 °C were used. The calcined shale powder was then passed through a No.200 sieve before being used to replace 20% of the cement in standard mortar samples. X-ray fluorescence spectrometery (XRF) was used to analyze the chemical composition of the calcined shale. In addition, the effects of replacing mortar with calcined shale were also examined with regard to setting time, pozzolanic activity, compressive strength, ultrasonic wave velocity, and the water absorption of the mortar. The test results demonstrate that the chemical composition of SiO2+Al2O3+Fe2O3 exceeded the 70% required by ASTM C618 specifications. The strength activity index (SAI) of calcined shale at 7, 28, 56 days exceeded 75%. At 28 days, the SAI values of samples produced with shale calcined at 700 °C and 800 °C exceeded 99%. After 28 days, the SAI, water absorption, and ultrasonic wave velocity values were nearly identical to those of control samples produced using only cement. Among all shale samples, those calcined at temperatures between 700 and 800 °C demonstrated the highest pozzolanic activity.
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Arı, V., O. Çakır, and S. Kuday. "Pair production of new heavy leptons with U(1)′ charge at linear colliders." International Journal of Modern Physics A 29, no. 11n12 (2014): 1450055. http://dx.doi.org/10.1142/s0217751x14500559.
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We study the pair production of new heavy leptons within a new U(1)′ symmetry extension of the Standard Model. Because of the new symmetry, the production and decay modes of the new heavy leptons would be different from those of three families of the standard model. The pair production cross-sections depending on the mixing parameter and the mass of heavy leptons have been calculated for the center-of-mass energies of 0.5 TeV, 1 TeV and 3 TeV. The accessible ranges of the parameters have been obtained for different luminosity projections at linear colliders. The search can be performed within the range of mixing parameter -1<x<-0.35 and 0.05<x<1, given that the heavy lepton mass Ml′ = 400 GeV at [Formula: see text] and L int = 100 fb -1. We find the sensitivity to the range of mixing parameter -1<x<1 for the mass range Ml′<800 GeV at [Formula: see text] and L int = 100 fb -1.
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Paret, Mathews L., Gary E. Vallad, Devron R. Averett, Jeffrey B. Jones, and Stephen M. Olson. "Photocatalysis: Effect of Light-Activated Nanoscale Formulations of TiO2 on Xanthomonas perforans and Control of Bacterial Spot of Tomato." Phytopathology® 103, no. 3 (2013): 228–36. http://dx.doi.org/10.1094/phyto-08-12-0183-r.
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Protection of crops from bacterial diseases presents a continuing challenge, mandating the development of novel agents and approaches. Photocatalysis is a process where chemically reactive oxygen species are catalytically generated by certain minerals in the presence of light. These reactive oxygen species have the capacity to destroy organic molecular structures critical to pathogen viability. In this study, the antibacterial potential of photocatalytic nanoscale titanium dioxide (TiO2), nanoscale TiO2 doped (incorporation of other materials into the structure of TiO2) with silver (TiO2/Ag), and nanoscale TiO2 doped with zinc (TiO2/Zn; AgriTitan) was evaluated against Xanthomonas perforans, the causal agent for bacterial spot disease of tomato. In vitro experiments on photocatalytic activity and dose dependency were conducted on glass cover slips coated with the nanoscale formulations by adding a known population of X. perforans strain Xp-F7 and illuminating the cover slips under a visible light source. TiO2/Ag and TiO2/Zn had high photocatalytic activity against X. perforans within 10 min of exposure to 3 × 104 lux. Greenhouse studies on naturally and artificially infected transplants treated with TiO2/Zn at ≈500 to 800 ppm significantly reduced bacterial spot severity compared with untreated and copper control. Protection was similar to the grower standard, copper + mancozeb. The use of TiO2/Zn at ≈500 to 800 ppm significantly reduced disease incidence in three of the four trials compared with untreated and copper control, and was comparable to or better than the grower standard. The treatments did not cause any adverse effects on tomato yield in any of the field trials.
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Kim, C., J. Lee, Y. Choi, et al. "Phase I dose-finding study of sorafenib in combination with capecitabine and cisplatin as a first-line treatment in patients with advanced gastric cancer." Journal of Clinical Oncology 27, no. 15_suppl (2009): 4559. http://dx.doi.org/10.1200/jco.2009.27.15_suppl.4559.
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4559 Background: We conducted a phase I dose-finding study of sorafenib (S) in combination with capecitabine (X) and cisplatin (P) in patients with previously untreated metastatic or inoperable advanced gastric cancer. Methods: Four dose levels of S, X, and P combination were tested. The doses of S (p.o. daily), X (p.o. on days 1–14), and P (i.v. on day 1) were escalated at the following schedule; level 1: S 400 mg/d, X 1,600 mg/m2/d, P 80 mg/m2; level 2: S 800 mg/d, X 1,600 mg/m2/d, P 80 mg/m2; level 3: S 800 mg/d, X 2,000 mg/m2/d, P 80 mg/m2; level 1A: S 800 mg/d, X 1,600 mg/m2/d, P 60 mg/m2. The cycle was repeated every 3 weeks. Dose limiting toxicities (DLTs) were evaluated only in the first cycles and a standard 3+3 dose escalation design was implemented. Results: A total 21 pts were enrolled in the study. No DLTs were observed at dose level 1 (n=3). One DLT (grade 3 diarrhea) was noted at dose level 2 (n=6), and 2 DLTs (two grade 4 neutropenias longer than 5 days in duration) were observed at dose level 3 (n=6), which made the level 3 dose the maximum tolerated dose (MTD). However, at cycle 2 and thereafter at dose level 2, the relative dose intensity (RDI) of S and X could not be maintained (mostly below 80%) due to the frequent dose reductions and cycle delays. So, we explored a new dose level (1A) between dose level 1 and 2. Since no DLTs were found in 6 patients at level 1A with RDI mostly above 80% throughout the treatment period, level 1A was determined as recommended dose (RD). Most frequent grade 3 and 4 hematologic toxicities were neutropenia (25.0% of cycles), and most frequent grade 2 and 3 non-hematologic toxicities were hand-foot syndrome (9.4%), asthenia (7.0%), and anorexia (5.5%). The objective responses were confirmed in 10 out of 16 patients with measurable lesions (62.5%; 95% CI, 38.8–86.2%). With a median follow-up of 8.1 months, estimated median progression-free survival was 10.0 months (95% CI, 1.6–18.4 months) and median overall survival has not been reached. Conclusions: Diarrhea and neutropenia were DLTs in this S, X, and P combination. The dose schedule of sorafenib 400 mg po bid daily with capecitabine 800 mg/m2 po bid on days 1–14, and cisplatin 60 mg/m2 iv on day 1 in every 3 weeks is recommended for further development in AGC. [Table: see text]
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Almomani, Mohammed A., Mohamad I. Al-Widyan, and Sulaiman M. Mohaidat. "Thermal shock resistance of yttrium aluminium oxide Y3Al5O12 thermal barrier coating for titanium alloy." Journal of Mechanical Engineering and Sciences 14, no. 1 (2020): 6514–25. http://dx.doi.org/10.15282/jmes.14.1.2020.26.0511.
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The high strength-to- weight ratio of titanium alloys allows their use in jet engines. However, their use is restricted by susceptibility to oxidation at high temperatures. In this study, the possibility of increasing the operating temperature of titanium alloys through using Yttrium Aluminum Oxide (YAG) as a thermal barrier coating material for Ti-6Al-4V substrate is studied. The study concludes that YAG can be utilized to increase the operating temperature of Ti-6Al-4V titanium alloy from around 350 °C to 800 °C due to its low thermal conductivity and phase stability up to its melting point. In addition, its lower oxygen diffusivity in comparison with the standard YSZ material will provide a better protection of the titanium substrate from oxidation. In this work, coating was created using atmospheric plasma spray. X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM) were used to examine coatings' composition and structure. The coating was characterized by thermal shock test, Vickers hardness test and adhesion strength test. X-ray diffraction indicated that the coating was of a partially crystalline Y3Al5O12 composition. The coating was porous with excellent thermal shock resistance at 800 oC, with a Vickers micro-hardness of 331.35 HV and adhesion strength of 17.6 MPa.
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Boniotto, Michele, Mario Ventura, Maria Francesca Cardone, et al. "Localization of a new highly repeated DNA sequence of Lemur catta (Lemuridae, Strepsirhini)." Genome 45, no. 5 (2002): 973–76. http://dx.doi.org/10.1139/g02-048.
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We have isolated and cloned an 800-bp highly repeated DNA (HRDNA) sequence from Lemur catta (LCA) and described its localization on LCA chromosomes. Lemur catta HRDNA sequences were localized by performing FISH experiments on standard and elongated metaphasic chromosomes using an LCA HRDNA probe (LCASAT). A complex hybridization pattern was detected. A strong pericentromeric hybridization signal was observed on most LCA chromosomes. Chromosomes 7 and 13 were lit in pericentromeric regions, as well as in the interspersed heterochromatin. Chromosomes 1, 3, 4, 17, 19, X, and microchromosomes (20, 25, 26, and 27) showed no signals in the pericentromeric region, but chromosomes 3 and 4 showed a positive hybridization in heterochromatic regions. The 800-bp L. catta HRDNA was species specific. We performed FISH experiments with the LCASAT probe on Eulemur macaco macaco (EMA) andEulemur fulvus fulvus (EFU) metaphases and no positive signal of hybridization was detected. These findings were also confirmed by Southern blot analysis and PCR.Key words: highly repeated DNA, FISH, chromosome rearrangements, heterochromatin, Malagasy lemurs.
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Chanthima, Natthakridta, Kazuhito Shimada, and Jakrapong Kaewkhao. "The Photon Attenuation Coefficients of Building Materials Containing with Lead Carbonate (PbCO3)." Advanced Materials Research 979 (June 2014): 395–400. http://dx.doi.org/10.4028/www.scientific.net/amr.979.395.
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The total mass attenuation coefficient (μ/ρ, cm2g-1) of gamma-ray for building materials containing with Lead Carbonate (PbCO3) have been studied. The raw building material have cement, sand and stone in the ratio 1 : 2 : 4. The raw material was mixed with 30% of PbCO3to be used as the sample material. The mass attenuation coefficient of the raw material has been calculated by theoretical approach using WinXCom program for the photon energy band from 1 keV to 100 GeV. The composition of sample material was analyzed by energy dispersive X-ray fluorescence spectrometer (EDXRF). The variations of mass attenuation coefficient are shown graphically and compared with that of standard shielding concretes. It was found that the sample building material has higher value of mass attenuation coefficient than standard shielding concretes at energy zone above 2–7 keV, 90–800 keV and 5 MeV–100 GeV.
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Price, C. W., E. F. Lindsey, and S. A. Letts. "EDS analysis of bromine in polymers." Proceedings, annual meeting, Electron Microscopy Society of America 49 (August 1991): 1046–47. http://dx.doi.org/10.1017/s0424820100089548.
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Design requirements for the Inertial Confinement Fusion program at LLNL frequently require polymers to be modified with known amounts of dopants without seriously degrading the surface finish. Techniques such as x-ray fluorescence permit reliable quantitative analyses of the dopants. However, our strong emphasis on surface finish requires frequent SEM examinations, and the need for rapid analyses instigated an evaluation of EDS to analyze bromine in the SEM. Brominated polymers based on polystyrene and a plasma-deposited hydrocarbon with a composition of approximately CH were analyzed. Since standard ZAF programs are not effective for hydrocarbon-based materials, calibration curves were generated by correlating Br Lα/C Kα peak ratios with known compositions. The ratio technique was selected because it was highly sensitive to bromine and provided an effective internal standard based on carbon. The analyses were performed using a thin window in a NORAN Micro-Z II Si(Li) EDS on a Hitachi S-800 FESEM. The specimens were coated with palladium.
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Toibek, A. A., K. T. Rustembekov, D. A. Kaikenov, and M. Stoev. "Synthesis and properties of double gadolinium tellurites." Bulletin of the Karaganda University. "Chemistry" series 103, no. 3 (2021): 67–73. http://dx.doi.org/10.31489/2021ch3/67-73.
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For the first time, double gadolinium tellurites of the composition GdMIITeO4.5 (MII — Sr, Ba) were synthesized by the solid-phase method. The solid-phase synthesis of samples was carried out from decrepitated gadolinium (III) and tellurium (IV) oxides, strontium, and barium carbonates according to the standard ceramic technology. The synthesis was carried out in the temperature range of 800-1100 °C. The samples obtained were confirmed by X-ray phase analysis. X-ray phase analysis was carried out on an Empyrean instrument in the XRDML Pananalitical format. The intensity of the diffraction maxima was estimated on a 100-point scale. X-ray diffraction patterns indexing of the powder of gadolinium tellurites — alkaline earth metals studied were carried out by the homology method. The reliability and correctness of the results of indexing the X-ray diffraction patterns are confirmed by the good agreement between the experimental and calculated values of the interplanar distances (d) and the agreement between the values of the X-ray and pycnometric densities. It was found that compounds GdSrTeO4.5 and GdBaTeO4.5 crystallize in the monoclinic system and have the unit cell parameters, namely GdSrTeO4.5 — a = 12.7610, b = 10.4289, c = 8.6235 Å, V° = 1141.83 Å3, β = 95.77°, Z = 5, ρrent. = 3.22, ρpikn. = (3.10±0.09) g/cm3; GdBaTeO4.5 — a = 15.7272, b = 15.8351, c = 7.1393 Å, V° = 1769.72 Å3, β = 95.53°, Z = 8, ρrent = 3.71, ρpick = (3.61±0.10) g/cm3. Using the Landiya method, the standard heat capacities of the compounds were estimated from the calculated values of the standard entropies, and the temperature dependences of the heat capacities of the gadolinium tellurites synthesized were determined in the temperature range of 298–850 K.
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LaBrecque, J. J. "Comparison of Elemental Sensitivities Induced by Radioisotope and Secondary Target Excitation for Simultaneous Multielement X-Ray Analysis." Advances in X-ray Analysis 35, B (1991): 1121–26. http://dx.doi.org/10.1154/s0376030800013392.
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SummaryThe major advantage of secondary-target X-ray fluorescence analysis is the enchancement of sensitivity and detection limit of an element or small group of elements with similiar atomic numbers by selecting a target material which produces X-rays slightly higher than the absorption edges of the analysis of interest. Secondary target excitation systems are, however, being employed for simultaneous determinations of a large range of elements. Thus, it was decided to compare the application of a simple secondary target X-ray fluorescence system with excitation from a Cd-109 annular radioisotope source.A simple secondary target X-ray fluorescence system was constructed and optimized which operates at less than 800 kilowatts. The “relative” elemental sensitivities of this system. and a radioisotope system with a Cd-109 annular source were compared by the analysis of the 1-2-3-multi-spectral standard from Chemplex which contains 1.23% of 53 elements. The characteristic X-rays were collected with the same Si(Li) detector and analyzed with the same Apple lie microprocessor with a Nucleus ADC/interface card. Finally, the secondary target system described herein with a molybdenum X-ray tube and zirconium or cadmium target produced similiar elemental sensitivities as a Cd-109 annular source of about 7.5 mCi and 5.0 mCi intensity respectively.
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Panizo-Espinar, G., T. Muñoz-Darias, M. Armas Padilla, F. Jiménez-Ibarra, J. Casares, and D. Mata Sánchez. "Optical nebular emission following the most luminous outburst of Aquila X-1." Astronomy & Astrophysics 650 (June 2021): A135. http://dx.doi.org/10.1051/0004-6361/202140323.
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Aquila X-1 is a prototypical neutron star low mass X-ray binary and one of the most studied X-ray transients. We present optical spectroscopy obtained with the Gran Telescopio Canarias (10.4 m) during the 2016 outburst, the brightest recorded in recent times and which showed a standard evolution with hard and soft accretion states. Our dataset includes a dense coverage of the brightest phases of the event, as well as the decay towards quiescence. We searched for optical winds by studying the profiles and evolution of the main emission lines and found no indisputable wind signatures, such as P-Cyg profiles. Nonetheless, our detailed analysis of the particularly strong and broad Hα emission line, detected at the end of the outburst, is consistent with the presence of a nebular phase produced by optically thin ejecta at ∼800 km s−1 or, alternatively, an extended disc atmosphere. We discuss these possibilities as well as the similarities with the phenomenology observed in other black hole and neutron star systems. Our study suggests that optical nebular phases might be a relatively common observational feature during the late stages of low mass X-ray binaries’ outbursts, enabling us to probe the presence of outflows at low-to-intermediate orbital inclinations.
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Comín, Romina, Mariana P. Cid, Luciano Grinschpun, Carlos Oldani, and Nancy A. Salvatierra. "Titanium-Hydroxyapatite Composites Sintered at Low Temperature for Tissue Engineering: In vitro Cell Support and Biocompatibility." Journal of Applied Biomaterials & Functional Materials 15, no. 2 (2017): 176–83. http://dx.doi.org/10.5301/jabfm.5000340.
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Background In clinical orthopedics, a critical problem is the bone tissue loss produced by a disease or injury. The use of composites from titanium and hydroxyapatite for biomedical applications has increased due to the resulting advantageous combination of hydroxyapatite bioactivity and favorable mechanical properties of titanium. Powder metallurgy is a simple and lower-cost method that uses powder from titanium and hydroxyapatite to obtain composites having hydroxyapatite phases in a metallic matrix. However, this method has certain limitations arising from thermal decomposition of hydroxyapatite in the titanium-hydroxyapatite system above 800°C. We obtained a composite from titanium and bovine hydroxyapatite powders sintered at 800°C and evaluated its bioactivity and cytocompatibility according to the ISO 10993 standard. Methods Surface analysis and bioactivity of the composite was evaluated by X-ray diffraction and SEM. MTT assay was carried out to assess cytotoxicity on Vero and NIH3T3 cells. Cell morphology and cell adhesion on the composite surface were analyzed using fluorescence and SEM. Results We obtained a porous composite with hydroxyapatite particles well integrated in titanium matrix which presented excellent bioactivity. Our data did not reveal any toxicity of titanium-hydroxyapatite composite on Vero or NIH3T3 cells. Moreover, extracts from composite did not affect cell morphology or density. Finally, NIH3T3 cells were capable of adhering to and proliferating on the composite surface. Conclusions The composite obtained displayed promising biomedical applications through the simple method of powder metallurgy. Additionally, these findings provide an in vitro proof for adequate biocompatibility of titanium-hydroxyapatite composite sintered at 800°C.
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Mahmoud, Ahmed S., Rabie S. Farag, Maha M. Elshfai, Lameas A. Mohamed, and Safaa M. Ragheb. "Nano Zero-Valent Aluminum (nZVAl) Preparation, Characterization, and Application for the Removal of Soluble Organic Matter with Artificial Intelligence, Isotherm Study, and Kinetic Analysis." Air, Soil and Water Research 12 (January 2019): 117862211987870. http://dx.doi.org/10.1177/1178622119878707.
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Zero-valent metals proved high reactivity to adsorb and degrade various contaminants removal. The chemically prepared nZVAl was characterized using UV-Vis spectrum, X-ray diffraction (XRD), and scanning electron microscope (SEM). This investigation explores the adsorption effect of nZVAl powder toward soluble organic compounds exemplified by chemical oxygen demand (COD) standard solution. The effect of different operating parameters was studied to identify the best removal conditions. All variable and covariable data were introduced to build statistical models. The effect of the operating parameter was studied at different pH (3-10), nZVAl dosages (0.1-0.8 g), at different times (5-120 minutes), stirring rate (50-400 RPM), and initial COD concentration (100-800 mg/L). The obtained results displayed that nZVAl is effective in the removal of standard COD solutions, where the removal percentages were 56% and 96% for 800 ± 18.0 and 100 ± 11.8 mg/L COD, respectively, at 10 minutes after using nZVAl dry dosage 0.6 g/L, pH 8, and rate 100 rpm. Also, the effect of nZVAl on other wastewater contaminants removal was studied and compared with Egyptian law for draining wastewater into nonfresh water (drainage-lakes-ponds) No. 48 of 1982 limits. The results of adsorption isotherm and kinetic model of COD fitted well to Freundlich isotherm and pseudo second order, respectively. Nonlinear artificial intelligence neural network (ANN) importance data agree with linear response surface methodologies (RSM) in simulating the adsorption of COD onto nZVAl indicating that the most significant coverable is adsorbent dose. Finally, this study appropriates using nZVAl in highly contaminated wastewater rather than other chemical and biological processes.
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Barbee, Troy W. "Multilayer Optics for the Soft X-Ray and Extreme Ultraviolet." MRS Bulletin 15, no. 2 (1990): 37–45. http://dx.doi.org/10.1557/s0883769400060449.
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This article considers a particular class of optic microstructure — multilayers for soft x-ray (SXR, 100 eV[124 Å] to 3,000 eV[4.1 Å] and extreme ultraviolet (EUV, 15 eV[800 Å] to 100 eV[124 Å] optics. Multilayers are manmade vapor-deposited depth-periodic layered micro-stractures of high enough quality to be considered synthetic crystals. Layers of two materials, A and B, having significant differences in their scattering powers for x-rays (electron densities) and of uniform thicknesses ta and tb are combined to form a sample of uniform in-depth period d0 ( = ta + tb). These microstructures are of scientific and technological significance since the high angle of incidence SXR and EUV reflectivities of single film reflectors is ~10−4) and since only a limited number of naturally occurring or synthetic large lattice constant materials efficiently diffraction reflect long wavelength radiation (SXR and EUV).Multilayer microstructure based SXR and EUV optics are direct analogues to standard quarterwave stacks applied at longer wavelengths with the requirement that absorption must be included. They are also analogous to atomic crystalline lattices in that one multilayer period is equivalent to one lattice plane. Thus, the multilayer structure forms a superlattice that diffraction reflects incident radiation. Multilayer diffraction may be modeled using x-ray scattering theory and obeys the refraction-corrected Bragg's law of crystal lattice diffraction. As will be discussed later, many factors determine the character of the multilayer response to an incident spectrum.
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Jovovic, Zoran, Zeljko Dolijanovic, Dusan Kovacevic, Ana Velimirovic, and Milan Biberdzic. "The productive traits of different potato genotypes in mountainous region of Montenegro." Genetika 44, no. 2 (2012): 389–97. http://dx.doi.org/10.2298/gensr1202389j.
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The results of three-year study of productivity for the five leading potato varieties in Montenegro: Riviera and Tresor (early), Kennebec (medium-early), Aladin and Agria (medium-late) are presented. The research was conducted during 2009, 2010 and 2011, on three highly diverse, related to the pedological and climatic conditions, locations in mountainous region of Montenegro: Niksic (800 m.a.s.l.), Kolasin (900 m.a.s.l.) and Zabljak (1450 m.a.s.l.). Field experiments were set up using standard methodology in random block design in four repetitions. The analysis of variance suggested that there were highly significant differences among genotypes (G), investigated years (Y) and locations (L) for potato yield. Apart from individual influence of the factors, their interactions (G x Y, G x L, Y x L, G x Y x L) were also highly significant for investigated trait. In average the highest yield (28.9 t/ha) was established at Kolasin locality. The highest yield of all investigated varieties and localities was measured at variety Agria (30.0tha-1), while the lowest at Riviera (24.6 t ha-1). In this investigation Agria variety was favourable for yield of potato tuber.
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Morita, Y., B. D. Payne, G. S. Aldea, et al. "Local blood flow measured by fluorescence excitation of nonradioactive microspheres." American Journal of Physiology-Heart and Circulatory Physiology 258, no. 5 (1990): H1573—H1584. http://dx.doi.org/10.1152/ajpheart.1990.258.5.h1573.
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An X-ray fluorescence system with low Compton background and high counting efficiency was developed to measure regional blood flow with nonradioactive microspheres. The performance of the system was tested in vitro by counting mixed aqueous solutions of either Mo, Ag, and I; Nb, Ag, and Ba; or Zr, Mo, Rh, Ag, Sn, I, and Ba, as well as a mixture of Ag and Ba nonradioactive microspheres. Mixtures containing 2-20 ppm of each element were counted for 10 min by the fluorescence system, and the individual elements in mixtures of three to seven nonradioactive elements were measured with high accuracy. The best counting statistics were obtained for Ag. For 10-min counts, the system measures as few as 120 Ag microspheres with 30% standard deviation but measures 800 Ag microspheres per sample with 3.6% standard deviation. We compared regional myocardial blood flows determined simultaneously by fluorescence and radioactive microsphere methods; the latter samples were counted by a 3-in. NaI (Tl) well detector and pulse-height analyzer. The radioactive and nonradioactive measurements showed good correlations.
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Suresh, M., S. Asath Bahadur, and S. Athimoolam. "Crystal Growth and Characterization of a New NLO Material: p-Toluidine p-Toluenesulfonate." Indian Journal of Materials Science 2013 (December 12, 2013): 1–4. http://dx.doi.org/10.1155/2013/680256.
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Single crystals of p-Toluidine p-Toluenesulfonate (PTPT), an organic nonlinear optical (NLO) material, have been grown by slow evaporation method at room temperature using ethanol as solvent. The crystal system was confirmed from the single crystal X-ray diffraction analysis. The functional groups were identified using FTIR spectroscopy. UV-Vis-NIR spectrum showed that the UV cut-off wavelength of PTPT occurs at 295 nm and it has insignificant absorption in the wavelength region of 532–800 nm. The SHG efficiency of PTPT was measured by employing Kurtz and Perry powder technique using a Q-switched mode locked Nd: YAG laser emitting 1064 nm for the first time and it was found to be 52% of standard KDP. Thermal and mechanical properties of PTPT were examined by TG/DTA and Vickers microhardness test, respectively.
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Qanytah, Khaswar Syamsu, Farah Fahma, and dan Gustan Pari. "Characterization of ball-milled bamboo-based activated carbon treated with KMnO4 and KOH as activating agents." BioResources 15, no. 4 (2020): 8303–22. http://dx.doi.org/10.15376/biores.15.4.8303-8322.
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Bamboo-based activated carbon was made using the activating agents KOH and KMnO4 at high temperature. This study examined the ability of unmilled and ball-milled bamboo activated using KOH or KMnO4 to fulfil the activated carbon standard parameters. Chemical activation was done using KOH and KMnO4 at 2.5% and 5% concentration, heated at 800 °C, and steamed for 1 hour. Sample size was reduced to 500 nm using high energy ball-milling at 500 rpm for 80, 150, or 180 min. Analysis included the yield, water content, ash content, volatile matter content, burn-off weight percentage, morphology analysis, functional groups (Fourier transform infrared spectroscopy, FTIR), crystallinity analysis (X-ray diffraction, XRD), and Brunauer, Emmett, and Teller (BET) analysis. Ball-milling treatment for 150 min produced activated carbon of 449 nm in size and a particle distribution index (PDI) score of 0.66. Ball milled activated carbon from the experiment had a pore radius ranging from 1.18 to 2.49 nm. The activated carbon that met the criteria of ANSI/AWWA B604-12 (2012) standard for moisture content, iodine number, and JIS K 1474 (1967) standard for methylene blue adsorption level and surface area were milled activated carbon with activator KMnO4 2.5%.
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Антонов, А. С., С. В. Новиков, Д. А. Пшенай-Северин та А. Т. Бурков. "Термоэлектрические свойства моносилицида кобальта и сплавов на его основе". Физика и техника полупроводников 53, № 5 (2019): 674. http://dx.doi.org/10.21883/ftp.2019.05.47561.19.
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The samples of cobalt monosilicide CoSi and its alloys with the substitution of iron or nickel for cobalt (Co$_1-x$M$_x$Si, M=Fe, Ni) were studied. The investigation were made for alloy compositions with iron content up to 10 at. % and nickel up to 5 at. %. The thermopower and electrical resistivity were measured in the temperature range of 100 – 800 K. Recent calculations of the cobalt monosilicide band structure revealed a number of essential differences from the standard semimetallic model with energy overlap of parabolic bands for electrons and holes. This raises the question on the effect of the new band structure features on the theoretical interpretation of experimental properties of the compound. We analyze the possibility of theoretical interpretation of temperature and concentration dependences of the thermopower and electrical resistivity using different models of the electron spectrum.
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Terzic, Anja, Jovica Stojanovic, Ljubisa Andric, Ljiljana Milicic, and Zagorka Radojevic. "Performances of vermiculite and perlite based thermal insulation lightweight concretes." Science of Sintering 52, no. 2 (2020): 149–62. http://dx.doi.org/10.2298/sos2002149t.
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This experimental study was conducted with an aim to investigate the effect of the elevated temperature on the mineral phase composition, microstructure and mechanical properties of the thermal insulation lightweight concretes. The first group of experimental concretes was based on the expanded vermiculite and expanded perlite used as lightweight aggregates (in 65 wt%) in combination with either ordinary Portland cement or refractory calcium aluminate cement. The mix-design of the second group of concretes comprised standard quartz aggregate, vermiculite or perlite as aggregate replacement (25 wt%) and binder (PC or CAC). A total of 10 concrete mix-designs were fabricated in form of 40?40?160 mm samples which were submitted to heat-treatment at 400?, 600?, 800? and 1000?C upon standard 28-days period of curing and hardening. The changes in crystallinity and mineral phase composition induced by temperature were monitored by X-ray diffraction technique. Microstructural visualizations of the non-fired and fired concrete samples were conducted by scanning electron microscopy accompanied with EDX analysis. The results indicated that despite the decrease in compressive strengths upon firing, investigated lightweight concretes can be categorized both as thermal insulators and structural materials.
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McCue, Morgan, Jamie L. Reichert, and Thomas D. Crenshaw. "Impact of dietary vitamin D3 supplements in nursery diets on subsequent growth and bone responses of pigs during an immune challenge." Journal of Animal Science 97, no. 12 (2019): 4895–903. http://dx.doi.org/10.1093/jas/skz347.
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Abstract Limited evidence is available to validate beneficial responses from extra nutrient supplements for mediation of growth suppression that results from immune challenges. Extrarenal roles of vitamin D metabolites in immune function implicate vitamin D3 supplements as a nutrient for potential beneficial effects. The current objective was to assess growth and bone ash responses to dietary vitamin D3 (D) supplements for growing pigs undergoing an immune challenge. At weaning, 216 crossbred pigs (4 pigs/pen, 6 pens/treatment) were randomly allotted within sex and weight blocks to 1 of the 9 treatments. Treatments included D supplements (0, 100, or 800 IU/kg) in a factorial arrangement with 3 vaccine (V) protocols; no injection (0 × V), a single 2 mL injection of a Lawsonia intracellularis vaccine at day 14 (1 × V), or 2 mL injections of the same vaccine at days 0 and 7 (2 × V). An adjustment diet with no supplemental D was fed for 1 wk, then assigned D diets for 2 wk (P2). After P2, all pigs were phase-fed standard diets (D = 280 IU/kg) to assess subsequent growth to 115 kg. No differences due to D supplements or vaccination protocol were detected in ADG (0.233 ± 0.021 kg/d) or GF (0.642 ± 0.028 kg/d) over the 21-d nursery trial; however, ADFI was lower (P &lt; 0.10) in pigs fed D levels of 0 vs. 100 and 800 (0.340 vs. 0.375, 0.372 ± 0.027 kg/d). Bone mineral content (g) from whole-body dual energy X-ray absorptiometry scans at 9 wk (n = 4 pigs/treatment) was lower in pigs fed 0 vs. 100 and 800 IU of D (287 vs. 325, 323 ± 34.1 g/pig). Growth from nursery to 115 kg was lower (P &lt; 0.01) in pigs fed D levels of 0 vs.100 and 800 (0.828 vs. 0.876, 0.889 ± 0.021 kg/d). At market, approximately two-thirds of pigs showed positive L. intracellularis serology titers regardless of treatment. Limited evidence for D-mediation of an immune challenge using the vaccination protocols may be a consequence of limited vaccine effects on growth in the nursery and seroconversion of most pigs to L. intracellularis by market.
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Yang, Jianhui, Qiang Fan, and Xinlu Cheng. "Prediction for electronic, vibrational and thermoelectric properties of chalcopyrite AgX(X=In,Ga)Te 2 : PBE + U approach." Royal Society Open Science 4, no. 10 (2017): 170750. http://dx.doi.org/10.1098/rsos.170750.
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The electronic, vibrational and thermoelectric transport characteristics of AgInTe 2 and AgGaTe 2 with chalcopyrite structure have been investigated. The electronic structures are calculated using the density-functional theory within the generalized gradient approximation (GGA) of Perdew–Burke–Ernzerhof functional considering the Hubbard-U exchange correlation. The band-gaps of AgInTe 2 and AgGaTe 2 are much larger than previous standard GGA functional results and agree well with the existing experimental data. The effective mass of the hole and the shape of density of states near the edge of the valence band indicate AgInTe 2 and AgGaTe 2 are considerable p-type thermoelectric materials. An analysis of lattice dynamics shows the low thermal conductivities of AgInTe 2 and AgGaTe 2 . The thermoelectric transport properties' dependence on carrier concentration for p-type AgInTe 2 and AgGaTe 2 in a wide range of temperatures has been studied in detail. The results show that p-type AgInTe 2 and AgGaTe 2 at 800 K can achieve the merit values of 0.91 and 1.38 at about 2.12 × 10 20 cm −3 and 1.97 × 10 20 cm −3 carrier concentrations, respectively. This indicates p-type AgGaTe 2 is a potential thermoelectric material at high temperature.
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Frantskevich, A. V., Anis M. Saad, A. K. Fedotov, A. V. Mazanik, and N. V. Frantskevich. "Formation of the Buried Insulating SixNy Layer in the Region of Radiation Defects Created by Hydrogen Implantation in Silicon Wafer." Solid State Phenomena 108-109 (December 2005): 187–92. http://dx.doi.org/10.4028/www.scientific.net/ssp.108-109.187.
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The radiation defects in 10 Ω⋅cm p-type and 4.5 Ω⋅cm n-type Cz Si were created at depth of 0.8-1 µm using 100 keV 2⋅1016 at/cm2 hydrogen implantation at room temperature. Then the introduction of nitrogen into silicon and its diffusion were carried out at different thermodynamic conditions. Finally, the samples were vacuum annealed at 800 oС during 2 h. The state of sample surfaces was studied by SEM. The depth and thickness of SixNy layer and also defect numbers were estimated by RBS method in the channeling mode. The electrical properties of the obtained structures were characterized by the transversal conductance measurements with the keep of a standard LCR-meter at a frequency of 1 MHz using the two-probe method. Our experiments have shown that the above-described method enables one to form the buried SiхNy layer with dielectric properties and the number of defects and nitrogen atoms on the silicon surface and in the near-surface region are comparable with those for the initial silicon wafers.
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ROA BOHÓRQUEZ, KAROL LIZETH, ENRIQUE VERA LÓPEZ, LUIS ALEJANDRO FONSECA PÁEZ, and GABRIEL PEÑA RODRÍGUEZ. "Microstructure, physical and mechanical properties of kaolin–diatomite composite reinforced with CaCO3•." DYNA 86, no. 210 (2019): 323–32. http://dx.doi.org/10.15446/dyna.v86n210.77450.
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The present work reports the microstructure, physical and mechanical properties of a material composed of kaolin, diatomite and calcium carbonate reinforcement (CaCO3). The ceramic prototypes were shaped by the slip casting method and sintered at temperatures between 800 °C and 1100 °C. The morphology and average pore size was analyzed by Scanning Electron Microscopy (SEM) and the mineralogical phases were determined by X-Ray Diffraction (XRD). The apparent density was established by the mercury immersion method according to the E – 8B Standard of the Institute of Ceramic Technology (ITC); the percentage of absorption was determined by the boiling method according to ISO 10545-3 standard; linear contraction was studied in three directions: long, wide and high. The study of the mechanical resistance to compression followed the procedure established at ASTM C773–88 standard and the breaking modulus was calculated by the three-point bending test, according to ISO 10545–4. Results show that the material structure is affected with increasing temperature reporting a decrease in quartz phase from 51.16 % to 33.81 %. Percentage of absorption revealed its most significant variation between 950 °C and 1100 °C with a decrease of 21 % approximately. Mechanical resistance values showed wide dispersion which was attributed to the different orientations in which the material failed during each test. According to the pore diameters found, the compound is characterized by being macro and mesoporous facilitating its application in catalysis, photochemistry, microelectronics and other microfiltration media
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Najwa, S., A. Shuhaimi, N. Ameera, et al. "Influence of RF Magnetron Sputtering Pressure on the Structural, Optical, and Morphological Properties of Indium Tin Oxide Nanocolumns." Advanced Materials Research 832 (November 2013): 276–80. http://dx.doi.org/10.4028/www.scientific.net/amr.832.276.
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In the present study, ITO nanocolumn was successfully deposited onto a glass substrate by RF magnetron sputtering. The effect of deposition pressure was investigated. X-ray diffraction analysis indicates that the intensity of the (400) peak orientation is highest at sputtering pressure of 5 mTorr. The results from UV-visible (UV-vis) spectroscopy revealed that the optical transmittance above 80 % was obtained from the all samples in the visible range of 400-800 nm. The larger grain size was observed from the top view of field emission scanning electron microscopy (FESEM) image as the sputtering pressure was increase. Dense nanocolumn arrays were obtained from the sample deposited at sputtering pressure of 5 mTorr. The surface roughness were decreased at high sputtering pressure of 10 mTorr was observed from atomic force microscopy (AFM) surface morphology. The electrical properties were obtained using standard two-point probe measurements. The lowest electrical resistivity was determined from the sample that prepared at sputtering pressure of 5 mTorr.
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Xu, X., L. L. P. Stee, J. Williams, et al. "Comprehensive two-dimensional gas chromatography (GC × GC) measurements of volatile organic compounds in the atmosphere." Atmospheric Chemistry and Physics 3, no. 3 (2003): 665–82. http://dx.doi.org/10.5194/acp-3-665-2003.
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Abstract. During the MINOS campaign in August 2001 comprehensive two-dimensional gas chromatography (GC x GC) was applied to the in situ measurements of atmospheric volatile organic compounds (VOCs) at the Finokalia ground station, Crete. The measurement system employs a thermal desorption unit for on-line sampling and injection, and a GC x GC separation system equipped with a flame ionization detector (FID) for detection. The system was optimized to resolve C7-C14 organic components. Two-dimensional chromatograms from measurements of Finokalia air samples show several hundred well-separated peaks. To facilitate peak identification, cartridge samples collected at Finokalia were analyzed using the same GC x GC system coupled with a time-of-flight mass spectrometer (TOF-MS). The resulting mass spectra were deconvoluted and compared to spectra from a database for tentative peak identification. About 650 peaks have been identified in the two-dimensional plane, with significant signal/noise ratios (>100) and high spectra similarities (>800). By comparing observed retention indices with those found in the literature, 235 of the identifications have been confirmed. 150 of the confirmed compounds show up in the C7-C14 range of the chromatogram from the in situ measurement. However, at least as many peaks remain unidentified. For quantification of the GC x GC measurements, peak volumes of measured compounds have been integrated and externally calibrated using a standard gas mixture.
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Petrella, Francesco, Monica Casiraghi, Davide Radice, Luca Bertolaccini, and Lorenzo Spaggiari. "Treatment of Chylothorax after Lung Resection: Indications, Timing, and Outcomes." Thoracic and Cardiovascular Surgeon 68, no. 06 (2020): 520–24. http://dx.doi.org/10.1055/s-0040-1710071.
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Abstract Background Chylothorax following pulmonary resection and lymphadenectomy for cancer is a potential severe complication in thoracic surgery. In the present study, we investigated the efficacy of the nonsurgical approach as well as the need for reoperation after conservative approach failure. Methods Chylothorax was diagnosed when chylous leakage from the chest drainage was observed and confirmed by the presence of triglycerides in the pleural fluid. We initially treated all the patients conservatively with complete oral intake cessation and total parenteral nutrition; if drainage output remained more than 800 mL/d after the first 5 days or major pleural effusion was observed at chest X-ray after chest tube removal, surgical treatment of chylothorax was indicated. Results Between January 1998 and December 2018, 5,072 patients underwent standard anatomical resection and mediastinal lymph node dissection for cancer at our institution. Among them, 30 patients (0.6%) developed chylothorax: 20 patients were effectively treated only by nil per os and low-fat diet, while 10 patients (33.3%) required surgical treatment. Mean age was 63 years; there were 24 male patients (80%); right-sided chylothorax was more frequent than left-sided chylothorax (22 vs. 8, respectively) although not statistically significant (p = 0.38); the only factor that seems to influence the need for reoperation is chylothorax flow rate during conservative treatment (p = 0.06). Conclusion Conservative treatment is effective in the case of low flow-rate chylothorax (< 800 mL/d); in the case of a higher flow rate, surgical exploration is needed and thoracic duct ligation—with or without lymphatic sites clipping—provides definitive lymphostasis.
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Bai, Kaikai, Jiangwei Shen, Zhenglu Zhu, et al. "Effect of Al2O3 on the Formation of Calcium Ferrite in the Solid State." Metals 9, no. 6 (2019): 681. http://dx.doi.org/10.3390/met9060681.
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Pure chemical reagents Fe2O3, Al2O3, and Ca(OH)2 were used to investigate the formation of calcium ferrite in the solid state. The phase composition of the prepared samples was determined using X-ray powder diffraction and by SEM. The TG-DSC analysis was performed to analyze the decomposition behavior and formation of calcium ferrites. The formation rate of calcium ferrite was determined by in-situ X-ray diffraction (XRD) and by the K-value method. The X-ray diffraction analysis was performed using Pt as the internal standard for application of the K-value method. The formation of Ca2Fe2O5 (C2F) occurred much earlier than the formation of CaFeO4 (CF). C2F and CF were formed at approximately 600 °C and 700–800 °C, respectively. With an increase of Al2O3 content, there was a tendency to decrease the melting temperature. There was a heating scheme in this study (i.e., 10 °C per minute to 1250 °C under a flowing atmosphere of high-purity air). The total amount of CF increased with an increase of the Al2O3 content, and the Al2O3 content reaching the maximum value of CF was 1.4%. As the Al2O3 content increased from 1.4% to 2.8%, the total amount of CF reduced slightly. When the Al2O3 concentration was greater than 2.8%, the content of CF generated significantly decreased with the increase of Al2O3.
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Azhari, Azhari, Gianto Gianto, and Suprijanto Suprijanto. "Comparison of the quality of the result of digitising panoramic analogue films using transmission and reflection scanner mode with direct digital imaging standard." Padjadjaran Journal of Dentistry 31, no. 2 (2019): 99. http://dx.doi.org/10.24198/pjd.vol31no2.21155.
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Introduction: The use of panoramic x-ray radiographs with analogue film negatives is still widely used. Contrast differences in the radiograph are determined by the level of light transmitted from the viewer to the film negative and visual perception of the radiologist, which can cause differences and errors of interpretation. This study was aimed to compare the quality of scanners produced by the transmission and reflection modes objectively with direct digital imaging standard. Methods: This study used a descriptive comparative design with purposive sampling method. Radiographic analysis was conducted towards 30 analogue radiographs of Radiology laboratory of Universitas Padjadjaran Dental Hospital. Digitisation was performed using a scanner with setting modes (reflection and transmission, 8-bit intensity resolution and spatial resolution of 800 dpi). Digitising the negative radiographs of analogue films into digital radiographs will get a range of percentage pixels. Histogram of radiographs with a percentage of pixels in the grey level range 0 - 64 exceeds 50%, including "under-exposed", in the grey level range 192 - 255 exceeding 50%, including "over-exposed". The evaluation was carried out to observe the radiograph exposure homogeneity by dividing the radiograph into 4 parts. Each part was calculated as the mean pixel value; then the standard deviation was searched for the four mean values (STDMI - standard deviation mean intensity) determined the homogeneity. Results: Digitising type of radiograph reflection was included under-exposed because the percentage of pixels in the grey level range 0 - 64 was 86.94%. STDMI consecutive reflection = 8.03, transmission = 18.05, direct digital imaging = 20.86. Conclusion: Digitisation with scanner transmission mode is the best result objectively because it approaches the quality value of direct digital imaging standard.Keywords: Objective quality, homogeneity, reflection, transmission
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Zhang, Shuqi, Dandan Dong, Qing Wang, Chuang Dong, and Rui Yang. "High-Temperature Oxidation Resistance of Alumina-Forming Austenitic Stainless Steels Optimized by Refractory Metal Alloying." Metals 11, no. 2 (2021): 213. http://dx.doi.org/10.3390/met11020213.
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Alumina-forming austenitic stainless steels are known for their superior high-temperature oxidation resistance. Following our previous work that solved the matching of major alloying elements in their specific 16-atom cluster formula, we here focus on the 800 °C air-oxidation resistance of 0.08 wt. % C alloy series satisfying cluster formula [(Al0.89Si0.05NbxTa0.06−x)-(Fe11.7−yNiyMn0.3)]Cr3.0−z(Mo,W)z, x = 0.03 or 0.06, y = 3.0 or 3.2, z = 0.07 or 0.2, to explore the effect of minor alloying elements Mo, Nb, Ta and W. This cluster formula is established particularly based on alloys which were originally developed by Oak Ridge National Laboratory. All samples are graded as complete oxidation resistance level according to Chinese standard HB 5258-2000, as their oxidation rate and oxidation-peeling mass are generally below 0.1 g/m2 × h and 1.0 g/m2, respectively. In alloys without Ta and W, a Cr2O3-type oxide layer is formed on the surface and Al2O3 particles of sizes up to 4 μm are distributed beneath it. In contrast, in Ta/W-containing alloys, a continuous protective Al2O3 layer is formed beneath the outer Cr2O3 layer, which prevents internal oxidation and provides the lowest weight gain. Instead of internal Al2O3 particles, AlN is formed in Ta/W-containing alloys. The W-containing alloy possesses the thinnest internal nitride zone, indicating the good inhibition effect of W on nitrogen diffusion.
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Li, Zonghao, Gong Yu, Jun Song, Qi Wang, Mousheng Liu, and Yaling Yang. "Study on the determination of heavy metals in water samples with ultrasound-assisted dispersive liquid–liquid microextraction prior to FAAS." Water Science and Technology 67, no. 2 (2013): 247–53. http://dx.doi.org/10.2166/wst.2012.524.
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A new, simple and rapid method based on dispersive liquid–liquid microextraction (DLLME) was developed for extracting and preconcentrating copper (Cu), nickel (Ni), lead (Pb) and cadmium (Cd) in water samples prior to flame atomic absorption spectrometry (FAAS) analysis. 1-(2-thiazolylazo)-naphthol (TAN) was used as chelating reagents, and non-ionic surfactant Triton X-114 and CCl4 as disperser solvent and extraction solvent, respectively. Some influential factors relevant to DLLME, such as the concentration of TAN, type and volume of disperser and extraction solvent, pH and ultrasound time, were optimized. Under the optimal conditions, the calibration curve was linear in the range of 10–800 μg L−1 for Cu and Ni, 10–500 μg L−1 for Pb, and 10–1,000 μg L−1 for Cd, respectively. The limits of detection for the four metal ions were below 0.5 μg L−1, with the enhancement factors of 105, 66, 28 and 106 for Cu, Ni, Pb and Cd, respectively. The relative standard deviations (RSD, n = 6) were 2.6–4.1%. The proposed method was applied to determination of Cu, Ni, Pb and Cd in water samples and satisfactory relative recoveries (93.0–101.2%) were achieved.
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Zohni, Wael, Rajesh Katkar, Rey Co, and Rizza Cizek. "Manufacturing Readiness of BVA(TM) Technology for Fine-Pitch Package-on-Package." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2014, DPC (2014): 000930–59. http://dx.doi.org/10.4071/2014dpc-tp26.
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Package-on-Package (PoP) has become common for packaging the processor and memory subunit in today's smartphones and tablets. Today's PoPs provide only about 300 interconnects between the base and top packages due to physical limitations posed by existing manufacturing methods. As a result, memory data bandwidth is limited to 25.6 GB/s at 1600 MHz DDR signal speeds. With a trend towards System-on-Chip (SoC) mobile processors with multi-core CPU, memory bandwidth requirements are sharply increasing. To meet these needs, a wide IO memory industry standard has emerged to specify 512 memory data interconnects. This standard provides about 4 times current bandwidths (&gt;100 GB/s) even at lower 800 MHz DDR signal speeds. For memory devices to offer 512 data lines, a total of about 1000 interconnects are needed to include the accompanying address, control, power and ground signals required for operation. No current PoP technology can offer 1000 interconnects, due to limited fine-pitch capability within the standard 14mm x 14mm package outline. Although industry expectation is for Through-Silicon-Via (TSV) technology to eventually offer a high-bandwidth solution, TSV manufacturing is still being developed and not expected to be widely available for a number of years. A new high-performance PoP interconnect technology called Bond-Via-Array (BVA [TM]) has been developed to provide high-bandwidth interconnect capability today. A BVA test vehicle package demonstrating 1020 processor to memory interconnects at 0.24mm pitch has been assembled inside the industry-standard 14mm x 14mm package outline. These fine pitch vertical interconnects are achieved utilizing well established wirebond equipment and process. As a result, BVA provides a cost-effective and reliable path to high-performance PoP. This paper details equipment and process developments related to high-volume-manufacturing (HVM) readiness of BVA technology. In addition to assembly process and equipment, test hardware that can accommodate fine pitch wire-tip interconnects needs to be demonstrated for manufacturing readiness. Socket and test hardware development and verification studies utilizing the latest 0.24mm pitch test vehicle are underway in cooperation with a 3rd party test hardware supplier. Goals include demonstrating feasibility of the fine-pitch PoP test approach as well as establishing sources for such hardware. In summary, BVA PoP technology enables 1000+ interconnects in a standard PoP outline while taking advantage of existing materials and infrastructure. To ensure manufacturing readiness, package assembly and test demonstrations are being carried out with third party vendors. Results indicate that with proper design and process optimization, high yield assembly and test is possible, and this technology is ready for high volume manufacturing.
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Gevin, O., O. Limousin, F. Lugiez, et al. "IDeF-X HD: A CMOS ASIC for the Readout of Cd(Zn)Te Detectors for Space-Borne Applications." Journal of Astronomical Instrumentation 10, no. 02 (2021): 2150009. http://dx.doi.org/10.1142/s2251171721500094.
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IDeF-X HD is a 32-channel analog front-end with self-triggering capability optimized for the readout of [Formula: see text] pixels CdTe or CdZnTe pixelated detectors to build a low power micro-gamma camera. IDeF-X HD has been designed in the standard AMS CMOS 0.35[Formula: see text][Formula: see text]m process technology. Its power consumption is 800[Formula: see text][Formula: see text]W per channel. The energy range of the ASIC can be extended to 1.1[Formula: see text]MeV thanks to the in-channel adjustable gain stage. When no detector is connected to the chip and without input current, a 33 electrons rms ENC level is achieved after shaping with 10.7[Formula: see text][Formula: see text]s peaking time. Spectroscopy measurements have been performed with CdTe Schottky detectors. We measured an energy resolution of 4.2[Formula: see text]keV FWHM at 667[Formula: see text]keV ([Formula: see text]Cs) on a single-pixel configuration. Meanwhile, we also measured 562[Formula: see text]eV and 666[Formula: see text]eV FWHM at 14[Formula: see text]keV and 60[Formula: see text]keV, respectively ([Formula: see text]Am) with a 256 small pixel array and a low detection threshold of 1.2[Formula: see text]keV. Since IDeF-X HD is intended for space-borne applications in astrophysics, we evaluated its radiation tolerance and its sensitivity to single event effects. We demonstrated that the ASIC remained fully functional without significant degradation of its performances after 200 krad and that no single event latch-up was detected putting the linear energy transfer threshold above 110[Formula: see text]MeV/(mg/cm2). Good noise performance and radiation tolerance make the chip well suited for X-rays energy discrimination and high energy resolution. The chip is space qualified and flies on board of the solar orbiter ESA mission launched in 2020.
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Baghdad, Abdelmalek, Rekia Bouazi, Youcef Bouftouha, Frédéric Hatert, and Nathalie Fagel. "Characteristics and firing behaviour of the under-Numidian clay deposits from the Jijel region (northeast Algeria): potential use in the ceramics industry." Clay Minerals 54, no. 4 (2019): 325–37. http://dx.doi.org/10.1180/clm.2019.51.
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AbstractThe Numidian Aquitano-Burdigalian nappe from the Jijel region (northeast Algeria) shows an important clay-rich basal series. In this study, seven representative clay samples were collected from the Djimla and El-Milia areas of this region in order to analyse their mineralogy using X-ray diffraction and Fourier-transform infrared spectroscopy, chemical composition by X-ray fluorescence, particle size, plasticity, morphology by scanning electron microscopy and their ceramic properties. Samples were prepared by pressing the clays and firing them at 800–1100°C, and bulk density, water absorption, linear firing shrinkage, weight loss and bending strength values were determined on the fired samples. The clays are mainly composed of kaolinite and illite, with a small amount of 10–14 Å interstratified clay minerals and chlorite, associated with quartz and feldspars. The main oxides in the samples were SiO2, Al2O3 and Fe2O3. The clays may be classified as moderately plastic according to their Atterberg limits. Ceramic tiles have been produced by dry pressing. At all tested firing temperatures, the clays present the required standard values for linear firing shrinkage, weight loss, bulk density, water absorption and bending strength, and they are defect-free. The main transformations were observed at 1000°C with the appearance of new crystalline phases. The measured technological properties of the investigated deposits confirm that the Numidian clays from the Djimla and El-Milia regions are suitable materials for the production of high-quality structural ceramics.
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FUNK, GERHARDT, DEVA O'NEIL, and R. MICHAEL WINTERS. "WHAT THE OBLIQUE PARAMETERS S, T AND U AND THEIR EXTENSIONS REVEAL ABOUT THE 2HDM: A NUMERICAL ANALYSIS." International Journal of Modern Physics A 27, no. 05 (2012): 1250021. http://dx.doi.org/10.1142/s0217751x12500212.
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The oblique parameters S, T and U and their higher-order extensions (V, W and X) are observables that combine electroweak precision data to quantify deviation from the Standard Model. These parameters were calculated at one loop in the basis-independent CP-violating Two-Higgs Doublet Model (2HDM). The scalar parameter space of the 2HDM was randomly sampled within limits imposed by unitarity and found to produce values of the oblique parameters within experimental bounds, with the exception of T. The experimental limits on T were used to predict information about the mass of the charged Higgs boson and the difference in mass between the charged Higgs boson and the heaviest neutral Higgs boson. In particular, it was found that the 2HDM predicts -600 GeV < mH± - m3 < 100 GeV , with values of mH± > 250 GeV being preferred. The mass scale of the new physics (M NP ) produced by random sampling was consistently fairly high, with the average of the scalar masses falling between 400 and 800 GeV for [Formula: see text], although the model can be tuned to produce a light neutral Higgs mass (~120 GeV). Hence, the values produced for V, W and X fell well within 0.01 of zero, confirming the robustness of the linear expansion approximation. Taking the CP-conserving limit of the model was found to not significantly affect the values generated for the oblique parameters.
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Anggresani, Lia, Yoli Nopita Sari, and Rahmadevi Rahmadevi. "Hydroxyapatite (HAp) From Tenggiri Fish Bones As Abrasive Material In Toothpaste Formula." Jurnal Kimia Valensi 1, no. 1 (2021): 1–9. http://dx.doi.org/10.15408/jkv.v1i1.19165.
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Cavities are one of the factors of dental and oral health problems that can be prevented by brushing teeth using toothpaste. Toothpaste can be made from a variety of chemicals, one of which is hydroxyapatite (HAp) which has good biocompatible properties. Hydroxyapatite can be obtained by utilizing tenggiri fish bone waste which has the main element of calcium. Fish bones soaked with NaOH and acetone are then calcined at 800 °C for 3 hours to obtain CaO powder and characterized its elemental content using X-Ray Fluorescence (XRF). CaO obtained was then reacted with (NH4)2HPO4 with a mole ratio of Ca/P 1.67 then heated at 90 °C, added NaOH up to pH 12, then the obtained deposits are filtered and calcined at 900 °C. The solids obtained from the calcination are then characterized using X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM). Hydroxyapatite (HAp) was formulated into toothpaste with the concentrations of 0% (F0), 45% (F1), 50% (F2), and 55% (F3). Toothpaste was evaluated using organoleptic tests, homogeneity tests, foam height tests, spreadability tests, pH and hedonic tests. XRD analysis shows that the resulting hydroxyapatite (HAp) has a crystal structure in accordance with ICSD standard No. 96-900-3549. SEM analysis showed that granular particles measuring 0.1 μm–0.3 μm in size. All formulated toothpastes (F0, F1, F2, and F3) meet the requirements of a good toothpaste. Hydroxyapatite (HAp) can be formulated into a good toothpaste with a concentration of 45%.
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Dhar, Sukanya, Pallavi Arod, K. V. L. V. Narayan Achari, and S. A. Shivashankar. "MOCVD of a Nanocomposite Film of Fe, Fe3O4 and Carbon Nanotubes from Ferric Acetylacetonate: Novel Thermodynamic Modeling to Reconcile with Experiment." MRS Proceedings 1752 (2015): 45–50. http://dx.doi.org/10.1557/opl.2015.7.
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ABSTRACTThermodynamic modeling of the MOCVD process, using the standard free energy minimization algorithm, cannot always explain the deposition of hybrid films that occurs. The present investigation explores a modification of the procedure to account for the observed simultaneous deposition of metallic iron, Fe3O4, and carbon nanotubes from a single precursor. Such composite films have potential application in various device architectures and sensors, and are being studied as electrode material in energy storage devices such as lithium ion batteries and supercapacitors.With ferric acetylacetonate [Fe(acac)3] as the precursor, MOCVD in argon ambient results in a nanocomposite of CNT, Fe, and Fe3O4 (characterized by XRD and Raman spectroscopy) when growth temperature T and total reactor pressure P are in the range from 600°C-800°C and 5-30 torr, respectively. No previous report could be found on the single-step formation of a CNT-metal-metal oxide composite. Equilibrium thermodynamic modeling using available software predicts the deposition of only Fe3C and carbon, without any co-deposition of Fe and Fe3O4, in contrast with experimental observations. To reconcile this contradiction, the modeling of the process was approached by taking the molecular structure of the precursor into account, whereas “standard” thermodynamic simulations are restricted to the total number of atoms of each element in the reactant(s) as the input. When Ocon (statistical average of the oxygen atom(s) taken up by each metal atom during CVD) is restricted to lie between 0 and 1, thermodynamic computations predict simultaneous deposition of FeO1-x, Fe3C, Fe3O4 and C in the inert ambient. At high temperature and in a carbon-rich atmosphere, iron carbide decomposes to iron and carbon. Furthermore, FeO1-x yields Fe and Fe3O4 when cooled below 567°C. Therefore, the resulting film would be composed of Fe3O4, Fe and C, in agreement with experiment. The weight percentage of carbon (∼40%) calculated from thermodynamic analysis matches well with experimental data from TG-DTA.
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Verbiţchi, Victor, Radu Cojocaru, Lia Nicoleta Boțilă, Cristian Ciucă, and Ion Aurel Perianu. "Considerations on the Ultimate Tensile Strength of Butt Welds of the EN AW 5754 Aluminium Alloy, Made by Friction Stir Welding (FSW)." Advanced Materials Research 1157 (February 2020): 38–46. http://dx.doi.org/10.4028/www.scientific.net/amr.1157.38.
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Experiments have been performed for the butt welding of 160 mm x 90 mm x 2 mm sheets of EN AW 5754 aluminium alloy, where the friction stir welding (FSW) has been used.Referring to the parent metal, the chemical composition and the form of wrought products of the aluminium alloy EN AW 5754 is presented, according to the standard EN 573-1:2005, respectively EN 573-3:2013. The mechanical properties of EN AW-5754 (Al Mg3) sheets are presented, according to EN 485-2:2016. The experiments have been conducted on the own equipment for friction stir welding, type FSW-4kW-10kN, to execute 8 (eight) FSW test pieces, according to EN ISO 25239-4. A quenched FSW tool, own-made of C 45 grade steel, EN 10083, has been used. The parameters of the FSW tests are shown. As main parameters, the rotational speed of the FSW tool was in the range n = 800 – 1200 rev/min, respectively the travel speed was in the range v = 50 – 200 mm/min. The run of the joining experiments is described and the joining test pieces are presented in figures. The ultimate tensile strength of the parent metal (σmin,pm) is based on the specified minimum tensile strength of the ”O” condition of the parent material, respectively this value is also required for the weld, that is σmin,w = 190 MPa. The specimens T1.0, T1.1, T2.1, T2.2, T3.1, T3.2, T4.1, T4.2, T5.1, T5.2 și T6.1 are adequate and accepted by this tensile test. The specimens T1.2, T6.2, T7.1, T72. and T8.1 can be accepted, if higher properties are achieved with a full postweld treatment. Another possibility is a lower extent of the minimum tensile strength of the weld that shall be in accordance with another design specification, for example σmin,w = 145 MPa. By the correlation of the FSW parameters with the results of the tensile test, the ranges for the main parameters with adequate values of the ultimate tensile strength are established: n = 800 – 1000 rev/min and v = 50 – 100 mm/min. By the conclusions, the main aspects of the execution of the FSW test pieces, as well as the results of the tensile tests are selected. The involved industrial areas of the applications are: electro-technique, electronics, manufacturing, shipbuilding and automotive industries. The FSW process is ecological, because it neither uses, nor produces hazardous substances. The references consist of 12 titles.
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Moskal, Grzegorz, Lucjan Swadźba, and Bartosz Witala. "Characteristics of Thermal Properties of Gd2Zr2O7 – ZrO2XY2O3 Powder Mixtures Intended for Deposition of Gradient Layers of TBC Type." Defect and Diffusion Forum 312-315 (April 2011): 577–82. http://dx.doi.org/10.4028/www.scientific.net/ddf.312-315.577.
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This article presents a study and results concerning the characteristics of selected thermal properties of the powders intended for deposition of gradient structure layers of the TBC type. The study included evaluation of the thermal diffusivity and specific heat of the powders in the initial state, and also calorimetric analysis of powder mixtures. Thermal diffusivity tests were performed with the laser-flash method. The temperature range of the tests was 25°C-1400°C. Specific heat and calorimetric analyses were performed with the heat flux method within a similar temperature range. The Gd2Zr2O7 powders obtained by spray drying method and standard ZrO2 x 8Y2O3 powder were analysed. The thermal diffusivity analysis and calorimetric analysis were performed for the samples obtained by pressing the Gd2Zr2O7 - ZrO2 x 8Y2O3 powder mixture of equal weight fractions. Specific heat measurements were taken for pure powders. The calorimetric analysis performed showed that no significant thermal effects were observed in both pure powders and their mixture within the temperature range of 800°C-1400°C. A small endothermic effect (approx.-7J/g) was observed for gadolinium powder within the temperature range of 350°C-615°C. Specific heat measurements revealed that gadolinium powder was characterized by stable values of that parameter within the whole temperature range like zirconium powder. The analyses performed showed that the powders were characterized by small mutual reactivity, and gadolinium powder showed a definitely lower thermal diffusivity, which is advantageous as regards obtaining TBC layers with a gradient structure on the basis of those two powders.
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Sparano, J. A., P. H. Wiernik, X. Hu, et al. "Pilot trial of infusional cyclophosphamide, doxorubicin, and etoposide plus didanosine and filgrastim in patients with human immunodeficiency virus-associated non-Hodgkin's lymphoma." Journal of Clinical Oncology 14, no. 11 (1996): 3026–35. http://dx.doi.org/10.1200/jco.1996.14.11.3026.
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PURPOSE To determine the following: (1) the feasibility of combining the antiretroviral didanosine (ddl) with a 96-hour continuous intravenous (IV) infusion of cyclophosphamide (800 mg/m2), doxorubicin (50 mg/m2), and etoposide (240 mg/m2) (CDE) plus filgrastim in patients with non-Hodgkin's lymphoma (NHL) associated with human immunodeficiency virus (HIV) infection; (2) the effect of ddl on CDE-induced myelosuppression and CD4 lymphopenia; and (3) the effect of CDE on serum p24 antigen and quantitative HIV blood cultures. METHODS Twenty-five patients with HIV-related NHL received CDE every 28 or more days. Consecutive patients were assigned in an alternating fashion to group A (ddl given at a standard dose during cycles one, two, five, and six) or group B (ddl given during cycles three, four, five, and six). RESULTS ddl use was associated with less leukopenia (mean nadir, 3.33 v 1.49 x 10(3)/microL; p = .03), neutropenia (2.38 v 1.07 x 10(3)/microL; p = .03), and thrombocytopenia (76 v 48 x 10(3)/microL; p = .059), and fewer RBC (1.6 v 3.1 per cycle; p < .01) and platelet transfusions (0.7 v 1.5 per cycle; p < .01), but had no significant effect on CD4 lymphopenia. Furthermore, lymphomatous bone marrow involvement and low CD4 count were associated with significantly greater myelosuppression. Although there was no substantial change in serum p24 antigen, the HIV blood culture became quantitatively more positive or converted from negative to positive in seven patients (64%). Complete response (CR) occurred in 58% of patients (95% confidence interval, 38% to 78%), median CR duration exceeded 18 months, tumor-related mortality was 20%, and median survival was 18.4 months. CONCLUSION Our results suggest that the CDE and filgrastim regimen is tolerable and effective for patients with HIV-associated NHL, and that combination with ddl is feasible and may result in less myelosuppression.
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Astik, Nidhi, Prafulla K. Jha, and Vasant Sathe. "Temperature dependent Raman Spectroscopic Study of the Fe doped La-=SUB=-0.67-=/SUB=-Sr-=SUB=-0.33-=/SUB=-MnO-=SUB=-3-=/SUB=- Prepared Using Ball Milling Method." Физика твердого тела 61, no. 4 (2019): 741. http://dx.doi.org/10.21883/ftt.2019.04.47423.302.
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AbstractPolycrystalline samples of La_0.67Sr_0.33Mn_0.65Fe_0.35O_3 (LSMFO) were synthesized using the standard ball mill method with different calcination temperatures ranging from 800 to 1100°C for 7 h. The phase purity of these samples was confirmed using X-ray diffraction (XRD) patterns. All samples were found to have rhombohedral crystal structure with $$R\bar {3}c$$ space group. The lattice parameters, cell volume, bond angle and bond length have been obtained using the Rietveld refinement by FullProf software. The average crystallite size calculated using the Debye-Scherrer formula was found between 27 and 60 nm. Surface morphology of the prepared samples has been examined using a scanning electron microscope (SEM). SEM images show the formation of well-arranged grain sizes distributed from 240 to 400 nm, much larger than one estimated using the Scherrer formula. All tiny particles are highly agglomerated with the increasing temperature and porosity decreases with increasing temperature. An analysis of the frequency and peak broadening of Raman modes as a function of temperature clearly shows the significant temperature effect on the A _1 g and E _ g modes of LSMFO. The shifts and broadening of the A _1 g and E _ g modes are discussed in light of the oxygen sublattice distortion. Our study shows the reduction in distortion with increasing calcination temperature, which suggests a decrease in the JT effect.
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Gagnon, P. A., and J. P. Agnard. "Twin-camera fixed-base photography of tree plots: possibilities and accuracy of a system." Canadian Journal of Forest Research 19, no. 7 (1989): 860–64. http://dx.doi.org/10.1139/x89-131.
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This paper investigates the stability and accuracy of a system using twin-camera fixed-base photography for the photogrammetric measurement of tree heights. Using basic matrix equations that relate photograph coordinates to ground coordinates, the general effects of errors of orientation parameters on tree heights are determined for the specific geometry of the system. It is shown that the most critical factor is the φ-inclination (the inclination of the camera along the axis perpendicular to the fixed base). The actual accuracy of the orientation parameters of each diapositive is then determined using a first-order analytical plotter (BC-1), with five stereopairs of tree plots taken at a nominal scale of 1:800. Because of the small base–height ratio, the standard deviations of the orientation parameters (ω, φ, κ) along the X, Y, and Z axes of each camera are high: between 10cc and 20cc (1cc = 0.01 grade). However, the cumulated effect of all the factors gives an accuracy within 30 cm for a tree height of 10 m. Compared with the effect of the relative orientation error in φ, the other factors have an almost negligible effect. Thus, important uncertainties concerning a practical system of deriving quantitative information from tree plots by photogrammetric means are clarified. Directions of further development are also indicated.
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Namjoshi, S. A., V. K. Jain, and S. Mall. "Effects of Shot-Peening on Fretting-Fatigue Behavior of Ti-6Al-4V." Journal of Engineering Materials and Technology 124, no. 2 (2002): 222–28. http://dx.doi.org/10.1115/1.1448323.
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The effects of shot-peening on the fretting fatigue behavior of titanium alloy, Ti-6Al-4V were investigated. Specimens were shot-peened as per AMS 2432 standard. X-ray diffraction analysis measured a maximum compressive stress of 800 MPa at the specimen surface, which reduced to zero at a depth of 188 μm. The compensatory residual tensile stress in the specimen was estimated using a curve fitting technique, the maximum value of which was found to be 260 MPa at a depth of 255 μm. Fretting fatigue tests were conducted at room temperature at a cyclic frequency of 200 Hz. Scanning electron microscopy of the shot-peened fretting fatigue specimens showed that the crack initiated at a point below the contact surface, the depth of which was in the range of 200–300 μm. Finite element analysis of the fretting fatigue specimens was also conducted. Fatigue life diagrams were established for the fretting fatigue specimens with and without shot-peening, and were compared to those under the plain fatigue condition, i.e. without fretting. Shot-peening improved the fretting fatigue life of Ti-6Al-4V; furthermore, it moved the crack initiation site from the fretting contact region to a region inside the specimen. Moreover, stress analysis showed that the fatigue failure of shot-peened specimens was caused by the compensatory tensile residual stress.
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Aguirre-Castro, Oscar Adrian, Everardo Inzunza-González, Enrique Efrén García-Guerrero, et al. "Design and Construction of an ROV for Underwater Exploration." Sensors 19, no. 24 (2019): 5387. http://dx.doi.org/10.3390/s19245387.
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The design of a remotely operated vehicle (ROV) with a size of 18.41 cm × 29.50 cm × 33.50 cm, and a weight of 15.64 kg, is introduced herein. The main goal is to capture underwater video by remote control communication in real time via Ethernet protocol. The ROV moves under the six brushless motors governed through a smart PID controller (Proportional + Integral + Derivative) and by using pulse-wide modulation with short pulses of 1 μs to improve the stability of the position in relation to the translational, ascent or descent, and rotational movements on three axes to capture images of 800 × 640 pixels on a video graphic array standard. The motion control, 3D position, temperature sensing, and video capture are performed at the same time, exploiting the four cores of the Raspberry Pi 3, using the threading library for parallel computing. In such a way, experimental results show that the video capture stage can process up to 42 frames per second on a Raspberry Pi 3. The remote control of the ROV is executed under a graphical user interface developed in Python, which is suitable for different operating systems, such as GNU/Linux, Windows, Android, and OS X. The proposed ROV can reach up to 100 m underwater, thus solving the issue of divers who can only reach 30 m depth. In addition, the proposed ROV can be useful in underwater applications such as surveillance, operations, maintenance, and measurement.
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Nguyen, Manh B., Giang H. Le, Trang T. T. Pham, et al. "Novel Nano-Fe2O3-Co3O4 Modified Dolomite and Its Use as Highly Efficient Catalyst in the Ozonation of Ammonium Solution." Journal of Nanomaterials 2020 (August 1, 2020): 1–11. http://dx.doi.org/10.1155/2020/4593054.
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Catalytic ozonation is a new method used for removal of NH4OH solution. Therefore, high catalytic performance (activity and selectivity) should be achieved. In this work, we report the synthesis and catalytic performance of Fe2O3-Co3O4 modified dolomite in the catalytic ozonation of NH4OH solution. Dolomite was successfully activated and modified with Fe2O3 and Co3O4. Firstly, dolomite was activated by heating at 800°C for 3 h and followed by KOH treatment. Activated dolomite was modified with Fe2O3 by the atomic implantation method using FeCl3 as Fe source. Fe2O3 modified dolomite was further modified with Co3O4 by precipitation method. The obtained catalysts were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), N2 adsorption–desorption (BET), and temperature-programmed reduction (H2-TPR). From SEM image, it was revealed that nano-Fe2O3 and Co3O4 particles with the size of 80–120 nm. Catalytic performance of activated dolomite, Fe2O3 modified dolomite, and Fe2O3-Co3O4 modified dolomite in catalytic ozonation of NH4+ solution was investigated and evaluated. Among 3 tested catalysts, Fe2O3-Co3O4 modified dolomite has the highest NH4+ conversion (96%) and N2 selectivity (77.82%). Selectivity toward N2 over the catalyst was explained on the basis of bond strength M-O in oxides through the standard enthalpy ΔH°f of oxide. Catalyst with lower ΔH°f value has higher N2 selectivity and the order is the following: Co3O4 (ΔH°f of 60 kcal (mole O)) > Fe2O3 (ΔH°f of 70 kcal (mole O)) > MgO (ΔH°f of 170 kcal (mole O)). Moreover, high reduction ability of Fe2O3-Co3O4 modified dolomite could improve the N2 selectivity by the reduction of NO3- to N2 gas.
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Richard, Afolabi O., Aftab Ahmad, and Kim Kiseon. "Security assessments of IEEE 802.15.4 standard based on X.805 framework." International Journal of Security and Networks 5, no. 2/3 (2010): 188. http://dx.doi.org/10.1504/ijsn.2010.032217.
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