An XPS study of dispersion and valence state of TiO2 supported vanadium oxide catalysts

Monolayer vanadium species are mainly in the V(V) valence state, but with XPS a small fraction of V⁴⁺ species are identified. Prolonged analysis treatment increases the V⁴⁺ concentration. With increasing vanadium concentration, a monolayer coverage corresponding to 1 mg V₂O₅ per m² develops, and it contains additional layers with a thickness of about 250 Å at 4 mg V₂O₅ per m², covering 3% of its surface area.     

Modification of E-glass fiber surfaces with polyacrylic acid polymers from an aqueous solution

The research reported in the article focuses on modifying glass fiber surfaces with polyacrylic acid (PAA) compounds. E-glass fibers were treated with aqueous polyacrylic acid solution. Polyacrylic acid exchanges its protons with the ions present in the glass surface. Hydrolyzed metal cations may form salt complexes with the dissociated polyacrylic acid. Angular dependent electron spectroscopy for chemical analysis (ESCA) demonstrated that the atomic concentrations of aluminum and calcium in the glass fiber surface were constant throughout the analyzed interval. The cation exchange property of glass fiber was studied using direct current plasma (DCP), which showed that both calcium and aluminum ions were extracted by low concentration polycrylic acid solutions. ESCA studies of were extracted by low concentrationb polyacrylic acid solutions. ESCA studies of the PAA-treated glass fiber showed that the amount of PAA of the glass surface increases with increased acid concentration. A broadened and shifted ESCA peak of the carbon (0 CO) indicates the formation of salt complexes between the polyacrylic acid and metal ions on the glass surface. Polyacrylie acid was modified by an esterification reaction with glycidyl acrylate (GA) in aqueous solution in order to insert organofuctional groups into the PAA chain.     

High‐Temperature Neutron Diffraction,Raman Spectroscopy,and First‐Principles Calculations of Ti3SnC2 and Ti2SnC

Herein, we report—for the first time—on the additive‐free bulk synthesis of Ti₃SnC₂. A detailed experimental study of the structure of the latter together with a secondary phase, Ti₂SnC, is presented through the use of X‐ray diffraction (XRD), and high‐resolution transmission microscopy (HRTEM). A previous sample of Ti₃SnC₂, made using Fe as an additive and Ti₂SnC as a secondary phase, was studied by high‐temperature neutron diffraction (HTND) and XRD. The room‐temperature crystallographic parameters of the two MAX phases in the two samples are quite similar. Based on Rietveld analysis of the HTND data, the average linear thermal expansion coefficients of Ti₃SnC₂ in the a and c directions were found to be 8.5 (2)·10^?6 K^?1 and 8.9 (1)·10^?6 K^?1, respectively. The respective values for the Ti₂SnC phase are 10.1 (3)·10^?6 K^?1 and 10.8 (6)·10^?6 K^?1. Unlike other MAX phases, the atomic displacement parameters of the Sn atoms in Ti₃SnC₂ are comparable to those of the Ti and C atoms. When the predictions of the atomic displacement parameters obtained from density functional theory are compared to the experimental results, good quantitative agreement is found for the Sn atoms. In the case of the Ti and C atoms, the agreement is more qualitative. We also used first principles to calculate the elastic properties of both Ti₂SnC and Ti₃SnC₂ and their Raman active modes. The latter are compared to experiment and the agreement was found to be good.     

A comparison of sodium methoxide-treated lards

The treatment of lard with interesterification catalysts can give a variety of products, depending on the time and temperature relationships used in the treatment. These products are distinguished from each other by several means; x-ray diffraction analysis, cooling curves, dilatometric analysis, photomicrographic analysis, and glyceride composition. A correlation of the physical and functional properties of these treated lards has been made, showing that a stable shortening with good baking characteristics is associated with complete and permanent alteration in lard crystal structure, that is, crystal modification. Shortenings from those lards which exhibit somebeta crystal properties either initially or on subsequent storage do not retain these desirable characteristics. Presented at the 34th fall meeting, American Oil Chemists' Society, New York, October 17–19, 1960.     

Variations in the composition of sterols,tocopherols and lignans in seed oils from fourSesamum species

Seeds from different collections of cultivatedSesamum indicum Linn and three related wild species [specifically,S. alatum Thonn.,S. radiatum Schum & Thonn. andS. angustifolium (Oliv.) Engl.] were studied for their oil contents and fatty acid composition of the total lipids. The oils from wild seeds were characterized by higher percentages of unsaponifiables (4.9, 2.6 and 3.7%, respectively) compared toS. indicum (1.4–1.8%), mainly due to their high contents of lignans. Total sterols accounted forca. 40, 22, 20 and 16% of the unsaponifiables of the four species, respectively. The four species were different in the relative percentages of the three sterol fractions (the desmethyl, monomethyl and dimethyl sterols) and in the percentage composition of each fraction. Campesterol, stigmasterol, sitosterol and Δ⁵-avenasterol were the major desmethyl sterols, whereas obtusifoliol, gramisterol, cycloeucalenol and citrostandienol were the major monomethyl sterols, and α-amyrin, β-amyrin, cycloartenol and 24-methylene cycloartanol were the main dimethyl sterols in all species. Differences were also observed among the four species in sterol patterns of the free sterols compared to the sterol esters.Sesamum alatum contained less tocopherols (210–320 mg/kg oil), andS. radiatum andS. angustifolium contained more tocopherols (ca. 750 and 800 mg/kg oil, respectively) than didS. indicum (490–680 mg/kg oil). The four species were comparable in tocopherol composition, with γ-tocopherol representing 96–99% of the total tocopherols. The four species varied widely in the identity and levels of the different lignans. The percentages of these lignans in the oils ofS. indicum were sesamin (0.55%) and sesamolin (0.50%).Sesamum alatum showed 1.37% of 2-episesalatin and minor amounts of sesamin and sesamolin (0.01% each).Sesamum radiatum was rich in sesamin (2.40%) and contained minor amounts of sesamolin (0.02%), whereS. angustifolium was rich in sesangolin (3.15%) and also contained considerable amounts of sesamin (0.32%) and sesamolin (0.16%).     

Activation of Ni/A12O3 catalysts through modification of the Al2O3 support

The effect of alumina pretreatment on the performance of alumina supported nickel catalysts was demonstrated in gas phase hydrogenation of toluene to methylcyclohexane. The state of the alumina was changed from pure to pure phase through various heat treatments in air. The catalysts were prepared from vapor phase by saturating the accessible binding sites on the pretreated alumina with the nickel precursor. The highest number of active sites for hydrogenation was observed for catalysts prepared on alumina having an incomplete phase transition and a / alumina phase ratio between 0.5 and 10. Results from temperature programmed desorption (TPD) studies revealed that a maximum in weakly chemisorbed hydrogen as well as in total amount of desorbed hydrogen was found for the same catalysts. By hydrogen chemisorption studies the total hydrogen uptake was found to correlate with the observed hydrogenation maximum. It is suggested that both the chemical and physical properties of the alumina influence the activity. An optimal metal-support interaction and structural defects on the alumina due to the phase transition can explain the observed maximum in the number of active sites and in hydrogen uptake.     

Probing the wurtzite conduction band structure using state filling in highly doped InP nanowires

We have grown InP nanowires doped with hydrogen sulfide, which exhibit sulfur concentrations of up to 1.4%. The highest doped nanowires show a pure wurtzite crystal structure, in contrast to bulk InP which has the zinc blende structure. The nanowires display photoluminescence which is strongly blue shifted compared with the band gap, well into the visible range. We find evidence of a second conduction band minimum at the gamma point about 0.23 eV above the band edge, in excellent agreement with recent theoretical predictions. Electrical measurements show high conductivity and breakdown currents of 10(7) A/cm(2).     

Margarine oil formulation and control

The formulation and control of margarine oils and margarines is based on an understanding of the relation between various physical measurements and the composition of the oils and margarines. Solid-to-liquid-fat ratios are determined by dilatometry or by nuclear magnetic resonance spectroscopy. Oils are chosen for their crystal habit under conditions of processing and finishing. Some margarine test methods involve appearance, oral melting characteristics, oil-off, slump or collapse, get-away, penetration, and spreadability. Many measurements are effective only when they describe conditions over a range of temperatures. These include dilatometry and consistency determinations which require multipoint measurements. Presented at the American Oil Chemists' Society Short Course on “Processing and Quality Control of Fats and Oils,” Aug. 29–Sept. 1, 1966, Michigan State University, East Lansing, Mich.