Authorship patterns in agricultural sciences in Egypt

This study examines patterns of authorship in nineteen Egyptian journals of agricultural science. Multiple authorship was found to be the predominant trend in the field and co-authored papers accounted for some 79 percent of the sample. The most common form of multiple authorship involved three people. Considerable variation was found among sub-fields and co-authorship was found to be most common in social-science related agricultural disciplines. The author found no significant differences in patterns of collaboration in the agricultural sciences in Egypt and two the other developing countries for which comparative data was available, India and Pakistan.     

β-Galactosidase in the acceleration of Ras cheese ripening

An attempt has been carried out to accelerate Ras cheese ripening by pre-treatment of cheese milk with β-galactosidase. Milk was treated with a β-galactosidase enzyme preparation, namely lactozym (1 ml/kg milk), at 33°C for 1 h or at 4°C for 18 h and used for Ras cheese making. Flavour intensity, formation of soluble nitrogen compounds, free amino acids and liberation of free fatty acids were enhanced in cheese made from β-galactosidase treated milk. In addition, the ripening period was reduced to 2 months compared with 4 months required for control cheese. Treatment of cheese milk with β-galactosidase at 4°C or 33°C showed a similar effect on the properties of cheese.     

Exergetic optimization of a solar photovoltaic thermal (PV/T) air collector

In this paper, an exergetic optimization has been developed to determine the optimal performance and design parameters of a solar photovoltaic thermal (PV/T) air collector. A detailed energy and exergy analysis has been carried out to calculate the thermal and electrical parameters, exergy components, and exergy efficiency of a typical PV/T air collector. The thermal and electrical parameters of a PV/T air collector include solar cell temperature, back surface temperature, outlet air temperature, open‐circuit voltage, short‐circuit current, maximum power point voltage, maximum power point current, etc. An improved electrical model has been used to estimate the electrical parameters of a PV/T air collector. Furthermore, a new equation for the exergy efficiency of a PV/T air collector has been derived in terms of design and climatic parameters. A computer simulation program has been also developed to calculate the thermal and electrical parameters of a PV/T air collector. The results of numerical simulation are in good agreement with the experimental measurements noted in the previous literature. Moreover, the simulation results obtained in this paper are more precise than the one given by the previous literature, and the new exergy efficiency obtained in this paper is in good agreement with the one given by the previous literature. Finally, exergetic optimization has been carried out under given climatic, operating, and design parameters. The optimized values of inlet air velocity, duct length, and the maximum exergy efficiency have been found. Parametric studies have been also carried out. Copyright © 2010 John Wiley & Sons, Ltd.     

An apparatus for characterization and control of isolated muscle.

An apparatus for characterization and control of muscle tissue is presented. The apparatus is capable of providing generalized mechanical boundary conditions to muscle tissue, as well as implementing real-time feedback control via electrical stimulation. The system is intended to serve as an experimental platform for implementing a wide variety of muscle control and identification studies that will serve as fundamental investigations of muscle mechanics, energetics, functional electrical stimulation, and fatigue. In one illustration of the capabilities of the apparatus, pilot experimental results of muscle workloops against a finite-admittance passive load are presented, illustrating how richer boundary conditions may reveal interesting muscle behavior.     

Effekt of Using a Starter Culture Grown on Soy Milk Medium on some Properties of “Ras” Cheese

Ras cheese was manufactured using a starter culture grown on soy milk medium. Resultant cheese was compared with that resulted by using the ordinary starter culture grown on skim milk medium. The use of the former starter resulted in increasing cheese acidity, total volatile fatty acids, formol and SCHILOVICH ripening indices throughout the ripening period. Also higher total bacterial number and lactic acid bacterial number were observed.     

Ripening changes of Ras cheese made from recombined milk as affected by certain additives

An attempt has been made to accelerate the ripening of Ras cheese made from recombined milk (RM). RM cheese was made from curd with either a mixture of Fromase 100 (fungal rennet) and Kapalase L (an animal lipase) at concentrations of 0·025 and 0·05% or a slurry of fully ripened cheese at concentrations of 1 and 2%. These treatments enhanced flavour development, body characteristics, formation of soluble nitrogen compounds and free fatty acids. The proteinase/lipase mixture was the most effective. A rancid flavour and bitter taste were developed in 3–4-month-old RM cheese made with the higher concentration enzyme mixture.     

Sur de nouveaux matériaux à base du bismuth trivalent de structures fluorine et pyrochlore

The study of the pseudo-binary systems Bi₂O₃-A₂B₂O₇, with A Cd²⁺, Pb²⁺, Mg²⁺ and B & Nb⁵⁺, Ta⁵⁺, reveals two types of solid solutions. The first one with Bi_1−2xCd_xB_xO_2−y (y = (1 − x)/2) formulation shows a fluorite-type structure whereas the second type with A_2−zB_2−zBi_2xO_7−z/2 formulation is obtained for A₂B₂O₇-rich compositions and possesses structures deriving from the pyrochlore type. The composition dependence of the unit cell parameters has been correlated to possible substitution mechanisms.

Résumé

D'une manière générale, l'étude des pseudo-binaires Bi₂O₃---A₂B₂O₇ (avec A Cd²⁺, Pb²⁺, Mg²⁺ et B Nb⁵⁺, Ta⁵⁺) a permis de mettre en évidence deux types de solutions solides: le premier de structure fluorine déficitaire en anions a pour formule Bi_1−2xCd_xB_xO_2−y (y = (1−x)/2); la seconde solution solide de composition A_2−z B_2−z Bi_2zO_7−z/2 est obtenue pour des compositions riches en A₂B₂O₇ et possède une structure qui dérive de celle du pyrochlore. Les paramètres cristallins des diverses phases isolées ont été déterminés à 298 K à partir des diffractogrammes X. Leur évolution a été corrélée avec le taux de substitution.     

Biosorption of Astrazone Blue basic dye from an aqueous solution using dried biomass of Baker's yeast

In this study dried biomass of Baker's yeast, Saccharomyces cerevisiae, is used as a sorbent for Astrazone Blue basic dye aqueous solution. Factors affecting the adsorption process: dye concentration, contact time, temperature and pH were investigated. The equilibrium concentration and the adsorption capacity at equilibrium were determined using three different sorption models namely: Langmuir, Freundlich and Temkin isotherms. It was found that increasing temperature and pH result in higher dye loadings per unit weight of the sorbent. The results gained from this study were described by Langmuir isotherm model better than Freundlich and Temkin isotherm models. The calculated heat of adsorption of the dye-yeast system indicates that the bio-sorption process is taking place by chemical adsorption and has an endothermic nature. The maximum adsorption capacity at 30 degrees C and pH 7 was calculated as 70 mg/g for dried biomass of Baker's yeast compared to 18.5mg/g for commercial granular activated carbon, indicating that dried biomass of Baker's yeast can be considered as a good sorbent material for Astrazone Blue solution.     

On the Heat Stabilization Efficiency of Polyester Plasticizers for Poly(vinyl chloride) (PVC)

Four different polyester plasticizers for poly‐(vinyl chloride) (PVC), having moderate acid numbers (11.5–20.5 mg KOH/g resin), were synthesized. These polyesters were modified by converting the terminal COOH group to Ba(II) and Cd(II) carboxylate salts in order to introduce the capability of heat stabilization for PVC. The modified polyesters were applied as dual function polyesters, i.e., as plasticizers and stabilizers at the same time. The thermal stabilization efficiency of the formed plasticized PVC films was tested photometrically and the data obtained were compared with that afforded by “Irgastab BZ 556”. The efficiencies of these modified polyesters as heat stabilizers for PVC were found to be comparable with that afforded by “Irgastab BZ 556”.