Galvanostatic polarizations of some Sn-Cd alloys in some carboxylic acids

The anodic and cathodic polarization of three Sn-Cd alloys in solutions of acetic, succinic and malic acids was investigated. Corrosion potentials of the three alloys did not vary appreciably with the concentration of the acid or its nature. Anodic polarization of the 65% Sn-Cd alloy revealed one arrest before the potential of O₂ evolution and corresponds to the SnO/SnO₂ system. Two arrests were manifested by the anodic curves in the case of the 50 and 35% Sn-Cd alloys; these correspond to the Cd/Cd⁺⁺ and SnO/SnO₂ systems respectively. Cathodic Tafel slopes (b-) for the h.e.r. on the three alloys range from –130 up to 202mV. Values of the exchange current densities (i ₀) range from 1.1×10^–7 up to 1.4×10^–10 A cm^–2.     

Pharmaceutical applications of some spanish clays (sepiolite,palygorskite, bentonite): some preformulation studies

In this work, a pharmaceutical preformulation study of four Spanish clays (two sepiolites, one palygorskite and one bentonite) is presented, comparing the results obtained with those of three mineral products currently used in pharmaceutical technology. The results showed that the mineralogical and chemical purity of these clays is similar and even higher than that of the three commercial products. The microorganism content is inside the range required for non-sterile pharmaceutical forms. We also determined two parameters concerning the clays' suitability for use in tablet manufacture (colour and water content) and one indicating appropriateness as an antidiarrheic product (adsorption capacity of methylene blue). The clays are yellowish white in colour, although correction does not seem necessary; water content varies according to the structure of the clay and storage conditions. Adsorption capacity of methylene blue is affected by the amount of hydration water present, dehydration temperature and the type of interchangeable cation found in the clay.     

Minerals in some Australian oil shales

The mineral composition of oil shales from three widely different ateas within Australia has been examined by X-ray diffractometry after low-temperature ashing. Quartz is more abundant than calcite. Feldspar is prominent in the Permian oil-rich shale from Glen Davis, New South Wales. Clay minerals are represented by smectite, illite, kaolinite and mixed-layer minerals (mostly mica-smectite). The content of clay minerals is generally low, except in the Tertiary oil shale from Rundle, Queensland.     

Absorption of CO2 in some hybrid solvents

Physico-chemical absorption data of CO₂ in three industrially important hybrid (physical + chemical) solvents were obtained in the temperature range of 0-25°C and at a constant partial pressure of the gas of 95.59 kPa. The systems studied were N-methyl 2-pyrrolidone, sulfolane and methanol with a minute quantity of 40% aqueous dimethyl amine (aq.DMA). The CO₂ uptake increased by two to three fold as compared to that of the pure physical solvents, and decreased with increases in temperature. Absorption also increased with the amount of aq.DMA added.     

Smoke-forming properties of some incombustible fibres

Conclusions The smoke-forming power of textile materials having a weight from 0.1 to 1.2 kg/m², made from Fenilon, Vniivlon, and Tulen fibres, is discussed.An approach has been proposed for comparing data on polymer smoke-formation. Fenilon evolves the greatest amount of smoke; its smoke-forming coefficient is approximately three times as large as those for Vniivlon and Tulen.Translated from Khimicheskie Volokna, No. 6, pp. 25–27, November–December, 1983.     

Comparison between some empirical equations of state for polymers

Some commonly used empirical equations of state for polymers are considered: the Spencer-Gilmore equation with two and three adjustable parameters, the Whitaker-Griskey equation, and the Rehage-Breuer equation. Also, a new equation is proposed: the Inverse Volume equation. These equations are evaluated with regard to fitting experimental P-V-T data and agreement with experimental data on isothermal compressibility and thermal expansion coefficient. The adjustable parameters for each equation are determined with the help of Rosenbrock's optimum-seeking technique. Analysis of the residuals on specific volume for a variety of materials suggests that the Spencer-Gilmore equation with three adjustable parameters, the Rehage-Breuer and the Inverse Volume equations yield the smallest and most random residuals and thus the least systematic error. The same three equations mentioned above yield results in good agreement with experimental isothermal compressibility data. However, among all the equations considered in this study, the Inverse Volume equation yields the best agreement with experimental thermal expansion coefficient data. Furthermore, it is the only equation to correctly predict the rise in thermal expansion coefficient with increasing temperature.     

Synthesis and characterization of some aromatic polyphosphonates

Novel aromatic polyphosphonates are synthesized by polycondensation of chloromethyl (methyl, phenyl) phosphonic dichloride with bisphenols using three procedures: melt, solution, and phase transfer catalysis. The molecular weights and spectral characteristics are presented. Mixtures of the polyphosphonates with polyacrylonitrile and nylon 66 are compatible only when the chloromethyl group is present. Eight percent of polyphosphonate in the mixture confers flame resistance to the polymers.     

Characteristics and performance of some commercial shortenings

Six different brands of commercial shortenings were evaluated for their physicochemical characteristics and baking performance of cakes and biscuits (cookies). Three of the samples were locally made shortenings supplied by three different refineries (coded A, B and C), and the other three samples were imported shortenings obtained from supermarkets in Kuala Lumpur (D, E and F). Analyses and evaluations included slip melting point, solid fat content, fatty acid composition, triglyceride composition, creaming power and baking performance. All of the shortenings had slip melting points above 40°C. Sample A had the highest solid fat content at all temperatures. However, in terms of baking performance in cakes, sample C gave the highest volume, followed closely by samples B and A. Results indicated that the cakes were significantly different (P < 0.05) in terms of grain size and eating quality. Sensory evaluation on biscuits indicated that samples made with shortening D were preferred by a majority of the sensory panel, followed by those made with shortening C. The third, in order of panel preference, was biscuits made with shortening E.     

Oxidation of some bulgarian coals. Influence of low-temperature oxidation on the microhardness and reflectivity of some brown coals

Experiments carried out with two clarain and three vitrain samples from the Bobovdol basin and two clarain samples from the Pirin basin have shown that changes in microhardness and random reflectance are useful indications of changes which occur in the coal substance during oxidation processes at 150 and 200 °C and subsequent extraction.     

The Oxidation of some Azaarenes with Ozone

Five azaarenes were oxidized with ozone. The rate constant was measured for three of them. Product studies showed that ring fragmentation occurs with phenanthrolines, acridine and phenazine. Ring fragmentation and oxygen insertion is observed with phenanthrydine. The fragmentation of the aromatic structure is suggested to derive from an electrophilic attack of ozone, whereas ozone acts as a nucleophile in the insertion of oxygen.     

The bulk volumes of some related siliceous materials

The bulk volumes of three related siliceous minerals have been determined in vacuo and at water vapour pressures up to saturation. The minerals are a quartz silica, forsterite (an orthosilicate) and a kaolinite clay. A tentative explanation of the results is made in terms of the particle size, surface polarity and density of the minerals.     

Mass spectral studies of some epoxy resin precursors

The mass spectra were determined of three epoxy resin precursors: N,N-bis-(2,3-epoxypropyl)-N′,N′-dimethyl-4,4′-diaminodiphenylenemethane (G2A); N,N′-bis-(2,3-epoxypropyl)-N,N′-dimethyl-4,4′-diaminodiphenylene methane (G2S); and N′,N′,N′,N′-tetrakis-(2,3-epoxypropyl)-4,4′-diaminodiphenylene methane (TGDDM); and of three related model compounds: N,N-dimethylaniline (DMA); N-methyl-N-glycidylaniline (MGA) and N,N-digrycidylaniline (DGA). The results helped to confirm the structure of the resin precursors and are intended to pave the way for subsequent thermal degradation studies of cured resin samples. Despite the similarity in chemical structure of the compounds studied there are quite large differences in the mass spectral results obtained.     

苯并-α-吡喃酮类生物活性物质的合成

从简单的原料2,3,4-三甲氧基苯甲醛出发,经选择性地去甲基化、Knoevenagel缩合关环、硝基还原及酰化等反应,设计合成了3个未见文献报道的3位酰氨基取代的苯并-α-吡喃酮类生物活性物质。其结构经1H NMR、13C NMR、IR分析确证。同时对合成过程中最关键的Knoevenagel缩合反应条件进行了研究,降低了反应溶剂的毒性并通过正交实验优化了合成工艺,确定较佳工艺条件为:以甲苯与环己烷(V甲苯∶V环己烷=7∶3)为溶剂,哌啶为催化剂,n(2-羟基-3,4-二甲氧基苯甲醛)∶n(硝基乙酸甲酯)∶n(催化剂)=1∶1.2∶0.20,反应温度98℃±2℃,反应时间6 h,平均收率87.2%,高于文献值。目标化合物是一种新的苯并-α-吡喃酮类物质,具有潜在的抗癌活性,有望成为新的抗癌药物。     

A Cold Chromate Etch Treatment for some Aluminium Alloys

A room temperature (cold) modification of the standard FPL chromic acid etching has been studied for three different aluminium alloys. Joints prepared in this way are as strong and durable as those prepared in the usual way at 62°C. The chemistry and morphology of the resulting oxide layers have been studied.     

Quantitative analysis of the phospholipids of some marine bioluminescent bacteria

Quantitative analyses of the phospholipids of three strains of marine bioluminescent bacteria were carried out after separation by two-dimensional thin layer chromatography. The phospholipids of all three species consisted of about 75% phosphatidyl ethanolamine, 13% phosphatidyl glycerol and 7% cardiolipin. The composition was only slightly affected by drastic changes in the growth conditions. One of the species contained poly-β-hydroxybutyrate. The fatty acids of another species contained principally straight and branched-chain 16 and 18 carbon fatty acids. No clue as to the nature of the elusive “aldehyde factor” of bacterial bioluminescence was found by analysis of aldehyde deficient mutants, indicating that possibly the factor is not a major phospholipid of these bacteria.     

Effect of gamma irradiation on the metal sorption and separation of some divalent metals by some new polymeric bifunctional resins

The metal sorption and separation of some divalent metals from solutions of varying acidity by a new series of gamma-irradiated ionic polymer resins have been investigated. Three polymeric resins, viz., phosphonic acid, phosphonate monoethyl ester, and phosphonate diethyl/monoethyl ester, were used in this study. The results of metal sorption and separation were compared with those of the well-known cation exchange resin Dowex X8. The results were correlated in the usual manner of distribution coefficients (D) of three divalent metals Sr(II), Co(II), and Ni(II). The results of metal sorption by the ionic resins under investigation compared with that of sulfonic acid resin, showed that Ni showed the highest affinity for the unirradiated monoethyl ester/phosphonic acid resin, while Sr showed the highest affinity for phosphonic acid resin and Co showed the highest affinity for mono/diethyl ester phosphonic acid resin. Moreover, the three metals (Sr, Co, Ni) showed the lowest affinity toward sulfonic acid resin. The calculated separation factors for the different resins indicate that the unirradiated phosphonic acid resin has the highest capacity to separate Sr from Ni, whereas mono/diethyl ester/phosphonic acid resins have the highest capacity to separate Co from Sr and Ni. Furthermore, the affinity of the ionic polymers for the metal ions was not greatly changed after gamma irradiation. © 1997 John Wiley & Sons, Inc. J Appl Polm Sci 65:1091–1101, 1997     

Quality and compositional studies of some edible leguminosae seed oils in Botswana

Seed oils were extracted with n-hexane from three edible Leguminosae seeds: Tylosema esculentum, Xanthocercis zambesiaca, and Bauhinia petersiana, giving yields of 48.2, 17.6, and 20.8% (w/w), respectively. Some physical and chemical parameters were determined to ascertain the general characteristics of the oils. The saponification and iodine values indicated that all three oil samples could be classified among the olive group of oils. This inference was supported by the results of the detailed fatty acid composition of the oils as determined by capillary gas chromatography. The ratio of total unsaturated to total saturated fatty acids in all three oil samples was approximately 70:30, with either oleic or linoleic acid being the dominant fatty acid. These results were in agreement with a proton nuclear magnetic resonance analysis of the fatty acid classes in the seed oils. Thus, the analysis served to justify the use of the three Leguminosae seed oils in food preparations. The work has further indicated that, with their attractive properties, the seed oils from T. esculentum, X. zambesiaca, and B. petersiana are good candidates for further studies to evaluate their future commercial prospects in the Southern African region.     

Polarographic behaviour of some potential antidiabetic benzylsulphonylarylazopyrazoles

The reduction of N′-benzylsulphonyl-3-methyl/phenyl-5-methyl/phenyl-4-arylazopyrazoles takes place in a single 2 e transfer, giving a diffusion controlled irreversible wave in B.R. buffer at dme corresponding to the reduction of azo group. A plausible mechanism has also been suggested on the basis of number of protons involved in the rate determining step and number of electrons involved in the reduction. Effect of various cations, anions and solvent percentage on the reduction have been discussed. The effect of substituents and ranges of potentials have been determined quantitatively by the application of Hammett equation in all the three series of compounds.     

Electrical and mechanical properties of some polymeric composites

Two unsaturated polyester resins based on poly[propylene‐phthalate‐hexane‐maleate] (PE1) and poly[oxydiethylene‐phthalate‐hexane‐maleate] (PE2) were prepared and crosslinked with styrene monomer. The structure of the prepared polyesters was detected using IR and NMR. The thermal behavior of the styrenated polyesters was determined using differential scanning calorimetry. The dielectric properties for the PE1 and PE2 styrenated polyesters and their mixtures with different ratios were also studied with a frequency range of 100 Hz to 100 kHz at room temperature (≈25°C). The mixture containing a 50/50 ratio of PE1/PE2 possessed the most promising dielectric properties. Thus, this sample was chosen along with the two separate styrenated polyesters to be loaded with three different types of fillers: calcium carbonate, clay, and quartz. This investigation led to the conclusion that the sample containing 50/50 PE1/PE2 loaded with 60–70% clay possessed the most promising dielectric properties. The compressive and tensile strength values were also studied for PE1, PE2, and their 50/50 mixture filled with the three types of fillers with the recommended concentrations (60 and 70%). The results indicated that the quartz composite (60%) had the best mechanical properties with respect to the clay and calcium carbonate. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1167–1180, 2002     

Fluidized-bed gasification of some Western Canadian coals

Three Western Canadian coals were gasified with air and steam in a fluidized bed of 0.73 mm sand and coal, at atmospheric pressure and temperatures of 1023–1175K to produce a low-calorific-value gas. One non-caking and two caking coals were tested. The effects of temperature, coal feed rate, $\text{air}\text{coal}$ ratio, $\text{steam}\text{coal}$ ratio, coal quality, coal particle size and bed depth on gas composition, gas calorific value and operating stability of the gasifier were established. Results are compared with those previously obtained for the same three coals when gasified in essentially the same equipment, but operated as a spouted bed.