Preliminary characterization of food tablets from date (Phoenix dactylifera L.) and spirulina (Spirulina sp.) powders

In this work, some physical properties (hardness, friability, disintegration time and erosion) of food tablets containing various food powders obtained from dates (Phoenix dactylifera L.), spirulina (Spirulina sp.) and oranges (juice and zest) were investigated. Also, experimental data related to the release kinetic of phycocyanin (antioxidant substance of spirulina) into different liquid mediums correctly fit the Korsmeyer-Peppas model since the coefficient of determination R² ranged from 0.84 (HCl 0.1 N solution) to 0.98 (distilled water). So, the date and spirulina powder-based food tablets could be of various uses: 1) consumption as such by all categories of consumers, 2) feeding of patients for whom it is difficult to chew or swallow food, knowing that these tablets can be either sucked or swallowed, and 3) as natural and cheap drug delivery carriers.     

Material Characterization of Ge1−x Sn x Alloys Grown by a Commercial CVD System for Optoelectronic Device Applications

High-quality compressive-strained Ge_1?x Sn _x /Ge films have been deposited on Si(001) substrate using a mainstream commercial chemical vapor deposition reactor. The growth temperature was kept below 450°C to be compatible with Si complementary metal–oxide–semiconductor processes. Germanium tin (Ge_1?x Sn _x ) layers were grown with different Sn composition ranging from 0.9% to 7%. Material characterizations, such as secondary-ion mass spectrometry, Rutherford backscattering spectrometry, and x-ray diffraction analysis, show stable Sn incorporation in the Ge lattice. Comparison of the Sn mole fractions obtained using these methods shows that the bowing factor of 0.166 nm (in Vegard’s law) is in close agreement with other experimental data. High-resolution transmission electron microscopy and atomic force microscopy results show that the films have started to relax through the formation of misfit and threading dislocations. Raman spectroscopy, ellipsometry, and photoluminescence (PL) techniques are used to study the structural and optical properties of the films. Room-temperature PL of the films shows that 7% Sn incorporation in the Ge lattice results in a decrease in the direct bandgap of Ge from 0.8 eV to 0.56 eV.     

Inhibition of asphaltene flocculation in light crude oil: effect of pressure,temperature and inhibitor concentration

Abstract

In this study, a light crude oil sample was taken from Hassi Messaoud field to characterize its physicochemical properties. The asphaltene flocculation onset was determined in the dead oil by Flocculation Titrimeter equipment. The petroleum resins have been extracted from the same crude oil and tested as an inhibitor of asphaltene flocculation then their efficiency has been studied at different conditions of pressure and temperature. The results point out that the extracted resins may have two different effects on the onset point depending upon the operator conditions and the concentration of the added resins to crude oil.     

Uniform thickness and colloidal-stable CdS quantum disks with tunable thickness: Synthesis and properties

Uniform thickness and colloidal-stable CdS quantum disks have been reproducibly prepared using cadmium acetate, elemental sulfur, fatty acids and octadecene as the starting materials without any size/shape sorting. The thickness could be varied between 1.2 and 2.2 nm, i.e., 4.5, 5.5, 6.5 and 7.5 monolayers of CdS along the thickness direction. These single crystalline disks with lateral dimensions between 20 and 100 nm adopted the zinc blende crystal structure with 〈100〉 (possibly mixed with 〈111〉) as the thickness direction. The basal planes and side facets were terminated with cadmium carboxylates, which dictated the thicknesses to be half a monolayer more than an integer number. Formation of CdS quantum disks probably occurs through a “nucleation-growth” mechanism, instead of aggregation of pre-formed magic clusters. Completion of a full monolayer along the lateral direction was found to be rather fast if two-dimensional nucleation was initiated on existing disks, which helped formation of atomically flat and thickness-controlled disks. As disk thickness decreased, the crystal lattice was found to dilate gradually, which has not been observed with CdS quantum dots. Compared with CdS quantum dots and rods, the disks displayed weakened quantum confinement and their photoluminescence lifetime (tens of picoseconds) was about two orders of magnitude shorter.      

On the secondary droplets of self-running gallium droplets on GaAs surface

Self-running droplets by thermal evaporation GaAs (001) surface are studied and analyzed using a scanning electron microscope. The sample is prepared under high-temperature annealing in an ultrahigh vacuum molecular beam epitaxy system. Particularly, secondary droplets which formed along primary droplet running trails are investigated. The secondary droplets are found to initially move along the [1 ?10] instead of [110] direction, but these droplets tend to turn into [110] direction as they grow bigger. The scanning electron microscope also captures nanoscale footprints of secondary droplets different from the main droplets.     

On Concurrency Control in Multidatabase Systems with an Extended Transaction Model

A major concurrency control problem that we have to cope in multidatabase systems is the global deadlock detection and resolution problem. This detection must take into account the autonomy of local systems, which make impossible the visibility of the state of local transactions. A well-known approach to detect such deadlocks, called potential global deadlocks, is one based on the potential conflict graph (PCG) appropriate for the multidatabase transaction model with a global commit protocol. This classical transaction model is very constraining for applications manipulating great volumes of information, and where subtransaction terminations (commit or abort) of global transactions are not totally dependant. In this paper we present an effective potential global deadlock characterization, and an efficient potential global deadlock detection algorithm, in multidatabase systems with an extended transaction model more suited for such applications.