Creation of Shock-Abrasion Resistance Build-up Metal Using a Physicochemical Model of High-Temperature Processes

Build-up metal for shock-abrasion resistance was the focus of this work, where the mathematical model of physicochemical high-temperature processes developed by the authors in their previous works was used. A computer program based on the model permitted forecasting of the required chemical composition and structure of the build-up metal. Flux-cored wires were fabricated from a cold-rolled ribbon (1008 steel) and filled with a powder mixture. Low carbon steel (A 516) was used as the base metal. The specimens were prepared by 3-layered build-up. The prepared specimens were tested using light microscopy, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDS), hardness measurements, and shock-abrasion resistance measurements. The results of the above-mentioned tests confirmed the correct calculation of the model and the good shock-abrasion resistance of the suggested build-up metal.     

Effect of surfactant concentration on the size of coated ferromagnetic nanoparticles

We demonstrate that the average size of the coated ferromagnetic Fe₂O₃ nanoparticles is controlled by the surfactant concentration in the coating solution. Magnetization as a function of this ratio first increases and then decreases exhibiting a peak. Surface area of the coated material shows inverse behavior, i.e. first decreases and then increases. Both curves have extrema at the same ratio of surfactant/substrate. We explain these features in terms of competition between surface and volume contribution to the total energy, where surface contribution is determined by the bonding energy between the surfactant SH-group and Fe₂O₃. We support our conclusions by employing transmission electron microscopy and elemental analysis.     

Successful treatment of early secondary myelofibrosis in SLE with IVIG

With increasing demand for esthetics, dentists face the challenge of delivering definitive restorations that fulfill patients' expectations of esthetics, biocompatibility, and durability. Recent technical developments have encouraged fabrication of gold-reinforced porcelain inlays that meet these important criteria. This article describes a sequence to construct metal-reinforced porcelain inlay restorations.     

Semi-automatic computer construction of three-dimensional shapes for the finite element method

Seven patients with idiopathic Parkinson's disease, aged 62 to 76 years, average duration of the disease approximately eleven years, suffering from severe hallucinosis and paranoid delusions of different degree, in whom conventional therapeutic strategies (administration of benzodiazepines and mild neuroleptics) had no antipsychotic effect, received clozapine, a non-classical highly potent neuroleptic, while blood count was strictly monitored. Paranoid ideas disappeared in all seven patients after a maximum of four days administration of 25-125 mg/day. No deterioration of parkinsonian symptoms, quantified according to UPDRS was seen. Given the protection of clozapine, we could increase the L-dopa dose in two cases, thereby improving the patients' motor function. Blood count showed no abnormalities in any of the patients during an average observation period of seventeen months. Our results support the assumption that clozapine has a potent antipsychotic effect in the treatment of psychotic decompensation in advanced Parkinson's disease in carefully selected patients. We saw no negative influence of the neuroleptic on extrapyramidal symptoms.     

Biological treatment of chemical industry effluents by stabilization ponds

The aim of the work has been to develop a biological treatment for chemical industry effluents.

A multistage photosynthetic chemostat, fed by chemical industry effluents, was operated continuously as a bench scale experiment aimed at testing the possibility of treating these effluents by means of stabilization ponds. 70–80% of COD and 80–85% of BOD could be removed together with the pesticidal activity present in the raw wastewater. Optimal number of reactors was found to be 6.

Most of the COD and BOD elimination took place during a 30 day detention time. The effluents cannot be considered suitable for free discharge, but can be disposed of by irrigating carefully a halotolerant vegetation.     

Improved efficiency of dye sensitized solar cells by treatment of the dyed titania electrode with alkyl(trialkoxy)silanes

Dye sensitized cells are improved by passivation of the dyed titania electrode by silanizing the dyed surface with alkyl(trialkoxy)silanes. In cells utilizing the ruthenium dye bis(4,4′-dicarboxy-2,2′-bipyridine)bis(thiocyanato)ruthenium (II) (N3) optimum performance is produced by treating the dyed electrode with octyl(trimethoxy)silane in dry toluene. Such treatment increases efficiency as much as 66%, raising cells utilizing an ionic liquid electrolyte with high [I₃⁻] from 1.7% to 2.8% (1 sun AM1.5). The effect on dark currents and on cell efficiencies of this silanization and of dyeing both the FTO and TiO₂ surfaces is discussed for ionic liquid and acetonitrile based electrolytes.     

HYDROFLUORIC ACID EXTRACTION BY TBP AND BY AMINES: I. A CRITICAL REVIEW OF THE HF-H2O-EXTRACTANT SYSTEM

Literature on HF extraction by amines and by tributyl phosphate is critically reviewed. The system amine-HF-H₂O shows an interesting feature concerning properties such as distribution curves compared to those for extraction of other acids, similarity to extraction by TBP, water extraction, selectivity, effect of amine type and dilution and diluent effect These properties sharply change (or even invert) when HF/amine molar ratio exceeds 2.     

One-step synthesis of prolate spheroidal-shaped carbon produced by the thermolysis of octene under its autogenic pressure

The dependence of the macroscopic shape of pure carbon on the precursor structure is observed using Reactions under Autogenic Pressure at Elevated Temperatures (RAPET) for the thermal dissociation of several precursors, including stearic acid, oleic acid, linoleic acid, methyl 3 butenoate, methyl butyrate, octadecane, octadecene, octane, octene and acrolein. The precursors are dissociated under their autogenic pressure developed at 700 °C to create a range of pure carbon microstructures. Prolate spheroidal-shaped carbon (PSSHC) is prepared by heating octene, among others, at 700 °C in a closed cell in a one-step process. The dimensions of the carbon bodies were 3–5 μm for the polar diameter and 6–8 μm for the equatorial diameter. Obtaining the PSSHC from octene is in contrast to a previous work, which required a long hydrocarbon chain and the presence of oxygen for the formation of PSSHC upon thermolysis under identical autogenic pressure. The products of the RAPET reaction of octene showed a strong ESR signal, resulting from nonbonding dangling electrons on the carbon surface. However, treating the carbons with a beam of hydrogen atoms has almost completely eliminated the ESR signal. The question why the thermal dissociation of some precursors yield PSSHC, while other precursors yield other morphologies, is discussed.     

HYDROFLUORIC ACID EXTRACTION BY TBP AND BY AMINES: MECHANISM,SPECIES FORMED AND UNIQUE PROPERTIES AT HIGH ACID TO AMINE MOLAR RATIOS

Analysis of data concerning HF extraction by amines reveals a change in extraction mechanism when HF/amine molar ratio in organic phase (Z) reaches 2. Up to this point extraction is by ion-pair formation and after it by H-bonding. As a result, the two HF molecules initially extracted differ in nature from subsequent ones. The change in mechanism explains why seemingly unrelated properties such as water co-extraction dilution and diluent effects, selectivity and viscosity - all change when amine bifluoride composition is attained. Similar change in extraction of other mono-basic acids occurs at Z=1. The system with Z>2 for HF is equivalent to that with Z>1 for other mono-basic acids and to that of extraction by TBP. It therefore provides a model for extraction from concentrated aqueous solutions.     

A microwave route for the synthesis of nanoflakes and dendrites-type beta-ln2S3 and their characterization

In this article, a simple microwave route was applied for the synthesis of nanoflakes and dendrite-type beta-indium sulfide (In2S3) in high yield (> 97%), using a homogeneous mixture of indium(lll)chloride and thiourea in an ethylene glycol (EG)/polyethylene glycol (PEG400) solvent. The reaction was conducted in a simple domestic microwave oven (DMO). Powder X-ray diffraction (XRD), low resolution and high resolution transmission electron microscopy (LRTEM and HRTEM), selected area electron diffraction (SAED), and energy dispersive X-ray spectroscopy (EDS), were applied to investigate the crystallinity, structure, morphology, and composition of the In2S3 nano-materials. Both the as-synthesized and calcined In2S3 products were a body-centered tetragonal (bct) phase, observed by XRD and HRTEM. The length and width of the resulting nanoflakes were in the range of 70-600 nm and 4-10 nm, respectively. The optical band gap of the powder was determined by diffuse reflectance spectroscopy (DRS) and was found to be 2.44 eV. The electronic properties of the products were studied by measuring the optical absorption spectra using photoacoustic spectroscopy. The band gap calculated by this method was found to be 2.52 eV. A possible mechanism for the formation of nanoflakes/dendrites-type In2S3 was also discussed.