Phosphorus seed coating increases phosphorus uptake,early growth and yield of pearl millet (Pennisetum glaucum (L.) R. Br.) grown on an acid sandy soil in Niger,West Africa

In pot and field experiments conducted in 1990 and 1991 on an acid sandy, phosphorus (P) deficient soil in Niger, West Africa, the effect of seed coating on seedling emergence, early growth and grain yield of pearl millet (Pennisetum glaucum (L.) R. Br.) was studied. Seeds of pearl millet were coated with different rates (0; 0.5; 1.0; 2.0; 5.0; 10.0 mg P seed^–1) and types of P fertilizers (single superphosphate, ammonium dihydrogen phosphate; monocalcium phosphate, sodium dihydrogen phosphate and sodium triphosphate). Seedling emergence was generally reduced at coating rates higher than 0.5 mg P seed^–1 and prevented with single superphosphate and sodium triphosphate at rates higher than 5 mg P seed^–1. No correlation was found between the pH and osmomolity of the coatings and final emergence of millet seedlings. The most favourable effect on plant growth and P content was achieved with ammonium dihydrogen phosphate (AHP) as seed coating. This was attributed to the enhancement effect of ammonium on P uptake. Compared to the untreated control dry matter production at 20 days after planting (DAP) was increased by 280%, P content per plant by 330%, total biomass at maturity by 30% and grain yield by 45%. Although seed coating with AHP may be harmful to seedlings emergence, it represents a suitable method to enhance early growth and increase yield of pearl millet.     

Use of cascade reduction potential for selective precipitation of Au,Cu, and Pb in hydrochloric acid solution

Optimization of reduction potential for electroseparation was studied for the recovery of gold, copper, and lead from acidic solution. A linear sweep voltammetric method enabled us to determine characteristic reduction potentials for each metal and the kinetics of the metal deposition indicated by current-voltage curves. In order to precipitate the metal species sequentially, reduction potentials were examined for the individual and mixed solutions of Au(III), Cu(II), and Pb(II). The three metals were reasonably well isolated from the mixed solutions such as Cu(II)/ Pb(II) and Au(III)/Cu(II)/Pb(II) in the order of the corresponding reduction potentials, in particular, the mass transfer controlled reduction potentials, obtained from linear sweep voltammetry (LSV) measurement.     

Refractories for lining mobile mixers

Conclusions New and effective refractories have been developed whose physicotechnical and working parameters are better than those of existing Soviet and foreign materials. Commercial production of them has been organized.MKFU-83 and KKFU-76 refractories increase mixer lining resistance by substantial factors and reduce the number of repair cycles and the material and labor costs, while increasing the metal output. The refractories are recommended for use in steel-melting processes (electric furnaces and buckets).Translated from Ogneupory, No. 2, pp. 24–26, February, 1991.     

Periclase —spinel products from magnesite powder with high alumina content

Conclusions Periclase-spinel articles with low contents of chromite made from magnesite powder containing magnesia-alumina spinel have a high range of physicochemical properties (except spalling resistance) and completely satisfy the requirements in service for the roofs of open-hearth and walls of electric steel-melting furnaces.With an increase in the content of magnesite in the fine constituent, it is possible to obtain products of the same quality from magnesite powder with a high porosity (up to 20–23%).The change in ratio of chrome spinel and magnesia-aluminous spinel in the periclase-spinel articles toward a certain increase in the latter is worthy of attention and requires further investigation.Translated from Ogneupory, No. 2, pp. 11–15, February, 1966.     

Artificial ageing of low density polyethylene film containing chemically bound UV - stabilizer

This paper deals with photostabilization of low density polyethylene films (LDPE) grafted with the UV-stabilizer 2-hydroxy-4-(3-methacryloxy-2-hydroxy-propoxy) benzophenone (HMB). The influence of grafting yield and the other grafting conditions upon photostabilization efficiency of LDPE films were then studied. The chemically bound monomer (HMB) was localized mainly near the surface of an LDPE film. The grafted LDPE film was exposed to an ultraviolet radiation source, and the degree of oxidation and other photooxidative changes were determined by transmission IR and ATR IR spectroscopy. Experimental results show that radiation grafting of a UV-stabilizer upon LDPE films is an efficient photostabilization method.     

Copper Complexes Obtained from the Schiff Base of Quinoline-2-Aldehyde and Aliphatic Diamines

Schiff base bis (2— quinolidene)- diamine gives a purple-red complex with copper ions with a λ_max at 530 mμ. The optimum pH for production of this complex is approximately 9.5. None of the metallic ions of the analytical groups II and III give rise to red complexes with the above Schiff base. Manganous (Mn²⁺) and stannous (Sn²⁺)ions as well as reducing agents such as hydrazine or hydroxylamine exert a catalytic effect on the rate of formation of these copper complexes. The thermal stability of the copper complex formed from the Schiff bases (2-quinoline-aldehyde with NH₂-(CH₂)_n-NH₂) is greater for diamine for which n = 4–6 than for n = 2–3.     

The search for optimum solutions for melting insulator glass

The effect of the temperature conditions of melting and the design features of the glass melting furnaces on the increase in the specific removal of glass melt in processing quenched insulating parts of high-voltage suspension insulators is demonstrated. Designs are proposed for glass melting furnaces and glass melting temperature regimes whose use will increase the economy of manufacturing insulators.     

Corundum-zircon crucibles for induction melting of nickel alloys

Refractories and Industrial Ceramics -     

Nucleation of isolated PO4 units on CeO2 driven by high temperatures and the effect on its oxygen storage and release properties

The chemical nature of P-containing species of varying concentration present in CeO₂ after impregnation with (NH₄)₂HPO₄ and calcination at 1273 K, and their effects on the oxygen storage and release (OSR) properties of ceria are reported for the first time. The samples were characterized by different techniques and the results were compared with those recently reported on the same samples but calcined at 873 K. When P-containing ceria solids were calcined at 1273 K, CePO₄ (monazite) was the predominant P-containing species on the surface of ceria, confirming previous studies that showed that monazite exists for those samples in which the surface P loading (P atoms per nm⁻²) is larger than 5.5. For lower surface P concentrations, isolated orthophosphate units are present at the surface and within the subsurface region of the solid. Severe sintering of CeO₂ after calcination at 1273 K resulted in P concentrations >5.5 P atoms·nm⁻² in all samples. Isolated PO₄ units that could initially be present in the samples calcined at 873 K nucleated and CePO₄ was formed when samples were calcined at 1273 K. OSR properties of CeO₂ deteriorated progressively when P loading increased due to the presence of larger crystals of the very stable Ce(III) phase of CePO₄ at the surface of the P-containing ceria solids.     

HYDRODYNAMIC MODELLING IN AN AIR-LIFT LOOP REACTOR

A simple hydrodynamic model is proposed for use in the design, scale-up and characterization of external loop air-lift reactors. The approach is based upon a momentum balance for the flow loop coupled with a drift-flux equation for the reactor riser and establishes a rational basis for a predictive model relating gas throughput to induced liquid flow and gas hold-up in a range of air-lift reactors. The effective resistance of the reactor, k, defined in terms of the total loss coefficients of the reactor and the aerated height of the two-phase riser, was identified to allow for the quantification of the influence of reactor design on the hydrodynamic variables. An extensive body of data for the air-water system, collected on two reactors with active volumes of 0·055 m³ and 0·3 m³, is presented and used, in conjunction with literature data encompassing a wide range of reactor geometries and flow conditions, to define a unique relationship between flow behaviour and reactor configuration. The model, which accounts for the prevailing flow regime in the reactor, provides a direct method of predicting hydrodynamic behaviour in relatively non-viscous systems.