Effect of depithing on pulps from egyptian bagasse

Egyptian bagasse was pulped by the prehydrolysis-soda process followed by multi-state bleaching. Raising the concentration of sodium hydroxide used in the second step of bleaching improved the chemical characteristics of the pulp. Depithing had to be applied to improve the degree of pulping and to reduce the ash content. The minimum ash content (0.07%) was arrived at either by carrying out depithing before prehydrolysis to the extent of 2%, or after prehydrolysis to the extent of 10%. Depithing before prehydrolysis was superior as it resulted in a better yield, higher alpha cellulose, and higher degree of whiteness.     

Synthesis of some new disperse anthraquinone dyes

1-Hydroxy and/or 1-aminoanthraquinone was allowed to react with formaldehyde in an alkaline medium to give 1-hydroxy or 1-amino-2-hydroxymethyl-9,10-dihydroxy-anthracenes, which gave on air oxidation, hydroxymethylanthraquinone derivatives (I). Interaction of 1-amino-2-hydroxymethylanthraquinone or its 4-bromo derivative with carbonyl compounds in the presence of an acid catalyst gave (1,3)oxazine derivatives (II). The methylene group in position-2 of the (1,3)oxazine ring was found to be highly reactive and reacted with carbonyl compounds to form the corresponding arylidenes (III). Selective oxidation of dimethyl oxazine derivatives with SeO₂ gave the corresponding dialdehyde (IV), which interacted with aromatic amines to give the corresponding Schiff bases (V). The bromine atom in the 6-position of II was easily replaced by aromatic amines to give blue disperse dyes (VI).     

Etude structurale du graphiture I de cesium

The metallic yellow compound CsC₈ belongs to the 1st stage. The formula CsC₈ involves the occupation, in each interlayer, of only one in four possible sites the compact structure would entail the composition CsC₂ (Fig. 1).From single crystal photographs, one can determine the c parameter as three times the identity period along the c axis: Ic.The structural determination is based on separate study of each family: 00l (Table 1, Fig. 2), hk0 and hkl (Table 2, Fig. 3) and powder diagrams (Table 3, Fig. 4). The hk0 family allows to determine the symmetry of the unit cell and the parameter; the systematic extinctions of the hkl reflections permit to determine the space group.The stacking of the cesium atoms: three in the four possible sites involves a screw axis 6₂ or 6₄. The position of the carbon and cesium atoms takes into account all the symmetries of the cells corresponding to the space group P6₂22 (or P6₄22) (Fig. 5). The foregone extinctions of those unit cells are respected, in particular, the 201, 202, 204…, reflexions are missed (Fig. 6).The two domains built on αβγ and αγβ are actually symmetric to a mirror and not superimposable. It is shown on Fig. 8 that there are two enantiomorphous structures: the stacking αβγ corresponds to an obverse screw axis for the cesium atoms.The presence of 6 different stacking zones even in a simple crystal involves a disorder in the compound which can explain the variations of intensity of the reflexions hk0 and hkl.The CsC₈ compound is described by an hexagonal unit cell belonging to the space group P6₂22 (or P6₄22) with 24 carbon atoms in position $\text{12k (x =}\text{1}\text{6}$, $\text{y =}\text{1}\text{3}$, $\text{z =}\text{1}\text{3}$) and $\text{6i (x =}\text{1}\text{6}$, z = 0 and $\text{x =}\text{1}\text{3}$, z = 0) and the cesium atoms in 3b. The parameters are $\text{a = 4.945 ± 0.01}\text{A}\text{?}$ and $\text{c = 17.76 ± 0.03}\text{A}\text{?}$.Two unit cells are mentioned, according to the direction of the screw axis. In fact, there are 6 different possible unit cells.We tried to imagine the different possibilities of stacking for the cesium atoms between the graphite layers. From an ideal graphite plane, one places the 1st cesium layer in position α. The second metallic layer can be placed on the β, γ or δ sites. Let us imagine a part in β position, an other in γ and the last one on δ. In the same graphite matrix, one can define three distinct domains spotted by the successions αβ, αγ and αδ. While the filling of the last cesium layer, each domain is divided in two and it appears 6 zones, which correspond to the stacking αβγ, αβδ; αγβ, αγδ; αδβ, αδγ (Fig. 7).Each of these domains is defined by an hexagonal unit cell. They differ one from each other.     

Myoglobin as a polymerase chain reaction (PCR) inhibitor: a limitation for PCR from skeletal muscle tissue avoided by the use of Thermus thermophilus polymerase

Skeletal muscle tissue contains polymerase chain reaction (PCR) inhibitors that are coextracted by conventional nucleic acid extraction procedures. Myoglobin, a heme-containing molecule, was shown to act as a potent Thermus aquaticus DNA polymerase inhibitor and is likely to be involved in muscle tissue-associated PCR inhibition. The use of Thermus thermophilus DNA polymerase avoids muscle tissue-associated PCR inhibition, and should be used in case of small amounts or instability of the targeted nucleic acid.     

Temperature Dependence of the Hardness of Nanocrystalline Titanium Dioxide

Vickers hardness of nanocrystalline ( N -) TiO₂ was measured in the temperature range 25° to 1200°C and it was compared with that of polycrystalline ( P -) TiO₂ in the same temperature range. N -TiO₂ showed a lower hardness than P -TiO₂ at temperatures up to 800°C which resulted in the lack of indentation crack traces for N -TiO₂ presumably implying more plasticity.     

Ultrasonic flaw detection based on mathematical morphology

The deterministic and statistical properties of morphological filters and their application in ultrasonic flaw detection have studied utilizing different structuring elements. It has been shown the effectiveness of the filtering process depends on the frequency content of input signals, the combination of morphological operations, and the parameters of the structuring elements. The statistical parameters (mean, variance, and skewness) of sequential morphological operations (i.e., dilation, closing, clos-erosion, and clos-opening) are examined in order to determine the noise suppression capability of morphological filters and their biasing effects. Experimental evaluation of morphological filters for flaw detection in the presence of strong scattering echoes is presented for A- and B-scans. The processed experimental results show that morphological filters can improve flaw visibility by suppressing microstructure scattering echoes. The performance of morphological filters is compared with that of recursive median filters and ensemble averaging using experimental data. Results indicate that morphological filters perform better than recursive median filters in preserving the geometric structure of the signal and can replace ensemble averaging which requires numerous measurements     

Oxalate content of some leafy vegetables and dry legumes consumed widely in Egypt

Oxalic acid and total oxalate contents were determined in four leafy vegetables and six dry legumes consumed widely in Egypt. The four vegetables, normally eaten raw, can be arranged according to their oxalate content, in descending order, as follows: green onion (leaves), green onion (bulbs), leek, radish (leaves), radish (roots) and roquette. Oxalic acid represented 76–86% of the total oxalates.Dry faba beans had the highest oxalic acid content, followed, in descending order, by fenugreek, lentils, peas, chickpeas and lupin. The ratio of oxalic acid to total oxalates differs according to the total oxalate content of the legume variety. Decortication, steeping, sprouting, stewing, boiling and baking reduced the oxalate content of seeds in different ways. Sprouting and steeping, followed by decortication, resulted in the most pronounced decrease in oxalates, especially in faba beans and lupin.