Miracle-dz/UniFAR-FTUs huggingface dataset:
Fabrication of Hydroxyapatite–Zirconia Composites for Orthopedic Applications

Dense hydroxyapatite–zirconia (HAp–ZrO2) composites are expected to have desired mechanical and biological properties for orthopedic applications. However, due to some processing problems, to date, this material can only be prepared by special techniques. In this paper, we report for the first time a facile route to prepare HAp–ZrO2 composites. Initially, HAp and ZrO2 powders were dispersed in aqueous media with polyacrylic acid and glutamic acid as the dispersants. The slurries exhibited a well-stabilized state at a high solid content (>50 vol%) and therefore green samples with high density (>60%) can be obtained after slip casting. These HAp–ZrO2 green samples can be easily densified by pressureless sintering at 1450°C with 2 h holding. After sintering, only hydroxyoxyapatite Ca10(PO4)6Ox (OH)2(1−x) (HOA), ZrO2, and trace amounts of α-tricalcium phosphate phases were detected. No obvious reactions between HAp and ZrO2 phase were observed. The HAp–ZrO2 samples showed excellent mechanical and biological properties. For 40 vol% HAp–60 vol% ZrO2 samples sintered at 1450°C, the flexural strength and toughness were 220 MPa and 4.37 MPa·m1/2, respectively. In addition, we observed the attachment, spreading, and proliferation of mesenchymal stem cells on the HAp–ZrO2 samples' surface. The results showed that the proposed colloidal processing and pressureless sintering process is feasible for preparing HAp–ZrO2 composites with high mechanical properties and promising bioactivity for orthopedic applications.
Recent developments in the stabilization of hydrogen peroxide bleaching of pulps: An overview

Hydrogen peroxide is used as a brightening and a delignifying agent in pulp bleaching. Transition metals such as Fe, Mn and Cu catalyze the decomposition of hydrogen peroxide. The excessive transition metal catalyzed decomposition leads to loss of active hydrogen peroxide and also to a decreased pulp strength. The metal profile must be optimized in order to diminish the decomposition. Harmful metals can be removed from the pulp before hydrogen peroxide bleaching by chelation or by acid washing. Traditionally inorganic salts of magnesium and silicate are used to stabilize the alkaline hydrogen peroxide. The use of environmentally friendly chelating agents as stabilizers has recently gained interest. This paper reviews the recent studies concerning the stabilization of hydrogen peroxide in pulp bleaching applications. The mechanisms behind the stabilizing action of conventional stabilizers and the mechanisms of the transition metal induced peroxide decomposition in pulp bleaching are reviewed. In addition, recent developments in metal removal by chelation are discussed.
Mechanism of selective methanol oxidation over vanadium oxide-titanium oxide catalysts: a FT-IR and flow reactor study

The mechanism of the selective oxidation of methanol on two V-Ti oxide catalyst samples, prepared by impregnation and coprecipitation techniques, respectively is investigated. The interaction of methanol and its oxidation products (i.e., formaldehyde, dimethoxymethane, formic acid, and methyl formate) is studied by FR-IR spectroscopy and compares with the results of flow reactor measurements performed at different temperatures, contact times, and methanol/oxygen molar feed ratios. The data are interpreted on the basis of a reaction mechanism which involved the following steps: (i) condensation of methanol with surface VOH groups; (ii) H abstraction from methoxy groups leading to coordinated formaldehyde; (iii) formation of dioxymethylene species by interaction of adsorbed formaldehyde with nucelophilic sites; (iv) reaction of dioxymethylene species with methanol to give dimethoxymethane; (v) successive oxidation of dioxymethylene groups to formate ions; (vi) reaction of these ions either with methanol to produce methyl formate or with water to give formic acid; (vii) decomposition of formate species to produce carbon monoxide; (viii) parallel oxidation of methanol to carbon dioxide. The behaviors of the surface species are compared with those monitored on other systems and the catalyst requirements for the title reaction are discussed.
Radionuclides in soils collected from within and around Los Alamos national laboratory: 1974–1996

Abstract A soil sampling program is the most direct means of determining the types, concentration/activity, and distribution of radionuclides within and around nuclear facilities. Los Alamos National Laboratory (LANL), for example, has had a soil surveillance program since the early 1970s and the purpose of this paper was to 1) evaluate this 20+ year data set to determine if there are any statistical differences in radionuclides (3H, 137Cs, 238Pu, 239,240Pu, 241Am, 90Sr, totU) and radioactivity (gross a, s, and γ), as a function of air emissions and fugitive dust, in surface soils (0–5 cm depth) collected from LANL, perimeter (PM) and background (BG) sites, and 2) determine if radionuclide concentrations are increasing or decreasing over time. Also, the total effective dose equivalent (TEDE) and the corresponding risk of excess cancer fatalities (RECF) to a PM community were estimated. Based on the long‐term average, nine out of the ten radionuclide parameters measured in LANL soils (n=12) were significan.
Evaluation of sequential extraction for speciation of trace metals in model soil containing natural minerals and humic acid

A model soil synthesized with several natural minerals and humic acid is used to evaluate the sequential extraction for speciation analysis of trace elements in soil. Although the recommended sequential extractants are able to bring the individual geochemical phases into solution at the experimentally defined stage, none of the extractants is completely specific and efficient. Various proportions of metals released at exchangeable, carbonate-bound, Fe-Mn oxide-bound, organic-bound fractions are readsorbed onto the other solid geochemical phases during sequential extraction. However, it is difficult to quantify the extent of readsorption and/or redistribution for the individual element and for the individual geochemical phase.
Processing Factors Impacting the Leakage Current and Flicker Noise of Germanium p + -n Junctions on Silicon Substrates

The impact of several processing factors, such as the n-well doping, the use of nickel-germanidation, and the postmetallization anneal (PMA) temperature, on the reverse current and flicker noise of p + -n junctions fabricated in epitaxial germanium-on-silicon substrates is investigated. It is shown that a higher well doping leads to a lower leakage current, in the range studied here, both for the perimeter and bulk component. It is furthermore shown that there exists an optimal PMA temperature around 450°C, depending on the leakage current component and the process details. The use of NiGe contacts improves the series resistance (forward current) but may deteriorate the perimeter leakage associated with surface-state generation at the Ge-SiO 2 interface. This is confirmed by the low-frequency noise results, showing a dominance of the perimeter component. It is demonstrated that these effects are related to the occurrence of Ni-germanidation-induced voids along the edge of the p + -n junctions.
Organic Functionalization and Morphology Control of Mesoporous Silicas via a Co-Condensation Synthesis Method

A series of new mesoporous silica materials with MCM-41 type of structure containing a homogeneous layer of organic functional groups inside the pores was prepared using a co-condensation method under low surfactant concentration condition. This reproducible synthetic approach resulted in high surface coverage with several functional groups such as a primary amine, secondary amine, urea, isocyanate, vinyl, and nitrile. In addition, the presence of organoalkoxysilane precursors during the base catalyzed condensation greatly influenced the final particle shape. By changing the precursor or its concentration, the particle morphology was tuned to various shapes, including spheres, tubes, and rods of various dimensions. The synthetic procedures that gave rise to the specific particle morphologies were investigated and the mechanism responsible for shape control was postulated. The structure and functionality of these materials were characterized by field-emission scanning electron microscopy, transmission elec.
PV-Powered MPPT Controlled Smart Parking System Using Inductive Coupling Charging Technique for Electric Vehicle

Electric vehicles (EVs) are being adopted at a rapid pace as an alternative to traditional combustion engine vehicles to limit reliance on fossil fuels and pollution. The availability of charging options is a major concern for EV customers. The development of charging infrastructure is one of the most difficult challenges in the implementation of EVs. Wireless charging systems (WCS) are becoming increasingly popular in the expanding EV market. This paper describes a wireless charging system for electric vehicles (EVs) that is powered by photovoltaic (PV) panels and employs inductively coupled power transfer topology. The receiver and transmitter components are separated by about 0.5 meter. As a result, as the receiver receives power to run the motor, the transfer is visible. Wireless power transmission technology makes use of a changing electromagnetic field. A steady current of charges creates a magnetic field around free space, which contains energy, and the electromagnetic field is generated between the coils and transmitted to the receiver. The system was modelled using Matlab/Simulink, and simulation was used to verify performance. Hardware prototype for the inductive coupling charging system has been developed and implemented.
Resolution of LC/1H NMR data applied to a three‐component mixture of polyaromatic hydrocarbons

A three‐component mixture of naphthalene, anthracene and pyrene with the middle peak embedded was recorded using LC/1H NMR. Two case‐studies, one with tailing peaks and one without, were analysed. A procedure was developed involving apodization, Fourier transformation, phasing and baseline correction of raw data, preprocessing by frequency shift and peak shape correction, variable selection, determination of key variables, eigenvalue plots to determine the number and position of components, and finally resolution using factor analysis. Copyright © 2002 John Wiley & Sons, Ltd.
Ionic liquids in external electric and electromagnetic fields: a molecular dynamics study

The non-thermal effects of external electric and electromagnetic fields in the microwave to far-infrared frequency range and at (r.m.s.) electric field intensities of 10−3 to 0.25 V/År.m.s. on neat salts of 1,3-dimethyl-imidazolium hexafluorophosphate ([dmim][PF6]) and 1-butyl-3-methyl-imidazolium hexafluorophosphate ([bmim][PF6]) have been investigated by means of non-equilibrium molecular dynamics simulation. Significant alterations in molecular mobility were found vis-à-vis zero-field conditions. Using Green–Kubo and transient time correlation function analysis, the electrical conductivity of these ionic liquids has been estimated. The results indicate that ionic liquids respond most significantly to frequencies much lower than those of smaller polar solvents such as water, although the mechanism of the field response is almost exclusively translational.
Photochemical Attachment of Polymer Films to Solid Surfaces via Monolayers of Benzophenone Derivatives

We report a simple and yet effective way to photochemically attach thin polymeric layers to solid surfaces. The system is based on a photoreactive benzophenone derivative that is bound to SiO2 surfaces via a silane anchor. This substrate is then covered with a polymer film that is reacted with the benzophenone moieties by illumination with UV light (λ > 340 nm). As a result of the photochemical reaction, a thin layer of the polymer is covalently bound to the surface. Nonattached polymer is removed by extraction. As examples, we have successfully attached thin layers of poly(styrene) and poly(ethyloxazoline). The thickness of the layer is a function of the illumination time and the molecular weight of the polymer. The film thickness increases linearly with the radius of gyration of the polymers used for attachment. Using this system, we were able to photochemically attach up to 16 nm thick films of poly(styrene).
Preparation and characterization of ordered mesoporous carbons on SBA-15 template

Ordered mesoporous carbons with high surface area were synthesized using SBA-15 as template at different temperatures. In the process, the precursor ferric acetylacetonate serves as the carbon source for nanofiber formation. In comparison with the morphology of carbon nanotube-encapsulated iron prepared without templates, the orientation of the carbon materials is controlled by the pore direction of the template. The microstructures of the mesoporous carbons are strongly dependent on the temperature of synthesis. Higher synthetic temperatures resulted in ordered mesoporous carbons with larger BET surface areas, pore diameters and increased pore volumes.
Fabrication of Photonic Band-Gap Crystals

We describe the fabrication of three-dimensional photonic crystals using a reproducible and reliable procedure consisting of electron beam lithography followed by a sequence of dry etching steps. Careful fabrication has enabled us to define photonic crystals with 280 nm holes defined with 350 nm center to center spacings in GaAsP and GaAs epilayers. We construct these photonic crystals by transferring a submicron pattern of holes from 70-nm-thick polymethylmethacrylate resist layers into 300-nm-thick silicon dioxide ion etch masks, and then anisotropically angle etching the III-V semiconductor material using this mask. Here, we show the procedure used to generate photonic crystals with up to four lattice periods depth.
Accurate calculation of the attractive interaction of two ground state helium atoms

Calculations were performed on the Van der Waals unteraction of two ground state He atoms. At each R, three calculations were done to obtain orbitals. One SCF calculation un the guven one-particle basis, and two atomic CI calculations carried out in one-and two-center basis sets. The effect of intra- atomic correlations was studied. (AIP)
Mechanisms of atomic layer epitaxy of GaAs

We have studied the surface chemistry of trimethylgallium and diethylgallium chloride on GaAs(100) surfaces as related to the atomic layer epitaxy (ALE) of GaAs. We have observed that during the Ga deposition, the reaction pathway of trimethylgallium changes such that there is significant CH3Ga emission at high Ga coverages. An examination of the Ga coverage dependence reveals that this stoichiometry dependent CH3Ga desorption can lead to self‐limiting Ga deposition which is a prerequisite for ALE. Numerical simulation of the reaction shows reasonable agreement with low‐pressure ALE growth data. Diethylgallium chloride was found to deposit GaCl on the GaAs surfaces, but with residence time decreasing rapidly with increasing Ga coverage. Again a numerical examination of this stoichiometry dependent phenomenon indicates that it can significantly contribute to the self‐limiting Ga deposition. Both systems showed that stoichiometry dependent reactions can be important mechanisms for the atomic layer epitaxy p.
Effects of Kefiran-Feeding on Fecal Cholesterol Excretion, Hepatic Injury and Intestinal Histamine Concentration in Rats

The natural polysaccharide, kefiran (galactoglucan), was studied for the mechanism of its serum cholesterol lowering effect in 2 rat models one, loaded with cholesterol and another given erotic acid. Kefiran accelerated sterol excretion and protected hepatic injuries (GOT, GPT) in both models. In addition, histamine excretion decreased in the cecum content and feces, suggesting that kefiran may have various preventative functions.
DUV and e-beam chemistry of high-sensitivity positive PMMA-based resist

We present an investigation to study the degradation of PMMA, poly(methyl methacrylate), and ARP-610, poly(methyl methacrylate-co-methacrylic acid), during e-beam and DUV exposure. The change in the chemical structure of the polymer materials were analyzed using UV, IR, NMR spectroscopy, gel permeation chromatography and GC-MS. The formation of anhydrides within the isotactic parts of the co-polymer causes a bimodel and multimodal distribution of the fragments and, therefore, a more efficient dissolution process.
Instrumental Texture of White Salted Noodles Prepared from Recombinant Inbred Lines of Wheat Differing in the Three Granule Bound Starch Synthase (Waxy) Genes

Texture is a key quality determinant of white salted noodles (WSN). Recombinant inbred lines (RILs) (n=130) of wheat with all combinations of the three Waxy genes provided a unique opportunity to relate granule bound starch synthase (GBSS) gene dosage with the texture of WSN using texture profile analysis. Harder noodles tended to be more adhesive and chewier (r=−0·68 and 0·97, respectively), whereas a reduction in adhesiveness was correlated with greater cohesiveness (r=0·65), springiness (r=0·72), and resilience (r=0·66). Cohesiveness and resilience were highly correlated (r=0·94). Highly significant variation existed among the RILs for all noodle texture parameters. Normal starch RIL noodles tended to produce the hardest, most adhesive and chewy, but least cohesive, springy and resilient noodles. Full waxy RIL noodles were the softest, thickest, least adhesive and chewy, and most cohesive and springy. Partial waxy RIL noodles generally were intermediate in texture. The GBSS genotype comprised 27–68% of the variance of noodle texture compared to 27–60% variance for RILs within GBSS class. Based on these results, starch composition is a major contributor to the texture of white salted noodles.
Progress and problems in activated polycondensation

New polycondensation methods for the synthesis of polymers based on non-traditional ways of activating monomers are classified. For the sake of convenience and as a contrast to traditional low-temperature polycondensation, it has been proposed to combine the new methods under the general title of "activated polycondensation". It is shown that the most versatile method in terms of synthesis is that based on the activation of the "leaving" part of the biselectrophile — the "activated amide and ester method". The considerable future potential of the latter is demonstrated. Problems related to the synthesis, structure, and reactivity of different classes of activated diesters are examined. The possibility of synthesising various heterochain polymers by reaction of activated diesters with di- and poly-functional nucleophiles is demonstrated. The advantages of this method for the synthesis of polymers are established. The bibliography includes 145 references.
Effect of Organic Matter on the Release Behavior and Extractability of Copper and Cadmium in Soil

Land disposal of organic waste materials may alter the heavy-metal status of the soil by affecting metal solubility or dissociation kinetics. The aim of this investigation was to study the influences of poultry manure and pistachio compost (at the rate of 300 g kg−1) on release behavior and extractability of copper (Cu) and cadmium (Cd) in two soils of Iran. For release studies, samples after incubation were extracted with ethylenediaminetetraacetic acid (EDTA) at pH 7.0 with shaker for periods of 5 to 2880 min. Results showed that during the reaction periods, Cu and Cd release rates were rapid at first and then became slower until equilibrium was achieved. In the two soils, extractability of Cu increased with poultry manure treatment and decreased with pistachio compost treatment as compared to the control soil, and extractability of Cd decreased with both pistachio compost and poultry manure treatments as compared to the control soil.
Differentiation of young red wines obtained in a warm climate region

Summary Five red wines obtained from the grape varieties: Tempranillo, Syrah, Merlot, Graciano and Pinot Noir-Cabernet Franc cultivated in the Montilla-Moriles region have been subjected to analysis of major volatile compounds, polyols and enological variables. Among the colours parameters highlight the total polyphenol contents and the absorbance at 520 nm of the Syrah and Graciano wine samples, whereas the higher alcohols concentrations show values below 400 mg L−1. The propanol, isobutanol, 2-methyl-1-butanol, 3-methyl-1-butanol and 2-phenylethanol have been used to distinguish by means of principal component analysis the five red wines. Only two components explained the 92.4% of the total variance.
Hybrid open frameworks (MIL-n). Part 4 Synthesis and crystal structure of MIL-8, a series of lanthanide glutarates with an open framework, [Ln(H2O)]2[O2C(CH2)3CO2]3·4H2O

The first series of rare-earth carboxylates with an open framework has been prepared hydrothermally (180°C, 3 days) by the action of glutaric acid on the metal chlorides in the presence of base. The crystal structure of the neodymium compound [Nd III (H 2 O)] 2 [O 2 C(CH 2 ) 3 CO 2 ] 3 ·4H 2 O has been determined by single-crystal X-ray diffraction. The composite material crystallizes in the monoclinic space group C2/c (no. 15) with a=8.1174(1) A, b=15.1841(3) A, c=19.8803(3) A, β=93.762(1)° (final agreement factors R 1 =0.0279, wR 2 =0.0693). The organic-inorganic network is three-dimensional and consists of chains of edge-sharing rare-earth polyedra NdO 8 (H 2 O) along the [100] direction, linked together by the carbon chains along two directions. The connection involves the formation of channels parallel to the rare-earth chains in which weakly bonded water molecules are incorporated. The analogous compounds were obtained with Pr, Sm, Eu, Gd, Dy, Ho and Y.
Effect of Alkali Cations on Aluminum Incorporation in Geopolymeric Gels

In geopolymeric gels, aluminum is known to have tetrahedral coordination and to be associated with an alkali cation to satisfy electronic neutrality. However, the mechanism of aluminum incorporation and the effects of different synthesis parameters are not well understood. 2H, 27Al, and 23Na MAS NMR techniques have been used to elucidate the structural properties and mechanism of aluminum incorporation in metakaolin-based geopolymers. Na+(aq) and Al(OH)4-(aq) species were detected in the pore solution of geopolymers with Si/Al ratios of ≤1.40 and found to be directly related to the concentration of soluble silicate in the activating solution used for synthesis. The relative concentration of Na+(aq) in sodium and mixed-alkali geopolymers indicated a preferential incorporation of potassium into geopolymeric gels during curing. This work demonstrates a direct link between the composition of the silicate activator and aluminum incorporation in geopolymeric gels.
DISSOLUTION RATE OF GYPSUM IN AQUEOUS SALT SOLUTIONS

We measured the dissolution rate of gypsum particles (0.5− to 1.0-mm fraction) in distilled water and in aqueous salt solutions of NaCl, MgCl2, Na2SO4, MgSO4, and CaCl2 at salt concentrations of 20, 40, and 60 mmol kg−1. Two gypsum samples were tested, one from a gypsum mine in Egypt and another from New Mexico, United States. We monitored the dissolution rate by measuring Ca concentrations in these solutions with and without shaking. The rate of gypsum dissolution increased with shaking and with increasing concentration of the salt solutions. Neither ion concentration nor species influenced the rate of gypsum dissolution when the rate was normalized by the solubility. The first-order reaction equation was unsuited for describing the dissolution process when Ca concentrations exceeded about 50% of gypsum solubility. The second-order reaction equation described the process well, providing a rate constant independent of ion concentrations or species.