This study is concerned with the adsorption of Congo red from solution on the surface of Chaff. The adsorption isotherm is of L-curve type according to Giles classification and the experimental data were best fitted to Langmuir isotherm model. The adsorption phenomenon was examined as a function of temperature (25, 40, 55 oC). The extent of adsorption of Congo red on Chaff was found to increase with the increase of temperature (endothermic process). The basic thermodynamic functions have also been calculated. The effect of contact time was investigated and found that the adsorption process of dye on Chaff surface reached complete equilibrium within 90 min. The maximum uptake of Congo red by Chaff was found to be 92.9% at 25oC. The kinetic data were well fitted to the Lagergren, pseudo-second order models. The results indicated that adsorption process followed the second order model. This behavior was discussed depending on the chemical structure of dye and Chaff surface. The kinetics of dye adsorption was also studied in terms of intraparticle diffusion model. The results indicated that intraparticle diffusion plays a significant role in the adsorption mechanism.
Mass transfer has been studied at rotating cylinder electrodes fabricated with spiral-wound woven-wire meshes using reduction of copper as a test reaction. The experimental data were correlated by an empirical expression between the Sherwood number and the Reynolds number, both regarding the hydraulic diameter as a characteristic length. It was found that the Sherwood number was dependent upon the Reynolds number to the power of 0.521. An enhancement factor was adopted to compare the efficiency of the new rotating cylinder electrode with previous three-dimensional rotating cylinder electrodes. The results showed that the new type has a mass-transfer enhancement factor 2.3 times higher than those obtained with smooth rotating cylinder electr
... Show MoreThe present study on some wild medical taxa has been carried out from the cytological view-points by using iron-acetocarmine squashtechnique.The chromosome numbers of Diplotaxis harra n=13, Eruca sativa n=11, both Carduus pycnocephallus n=29 and Datura stramonium n=10 were the new reports. Avariety of abnormal Chromosomal behaviours including, early & late disjunction, laggards, bridges, stickiness, and disturbed polarity were observed, albite with low frequency. All sorts of chromosomal abnormalities were counted at I &II meiotic stages. The stickiness frequency was slightly higher than others abnormalities in most stages, The highest stickiness numbers were noted in telophase I/II of D. harra (8.88%), C. pycnocephalis (4.25%),
... Show MoreBackground: Poly (methyl methacrylate) has several disadvantages (poor mechanical properties) like impact and transverse strength. In order to overcome these disadvantages, several methods were used to strengthen the acrylic resin by using different fibers or fillers. This study was conducted to evaluate the effect of Plasma treatment of the fiber on mechanical properties Poly (methyl methacrylate) denture base material. Materials and methods: Specimens were prepared from poly methyl metha acrylic (PMMA) divided according to present of fiber into 4 groups (first group without fiber as control group, second group with Plasma treated polyester fibers, third group with Plasma treated polyamide fibers and fourth group Plasma treated combination
... Show MoreConverting green areas and agricultural land into built-up areas is one of the most significant effects of urbanization in Iraqi cities. Greenery spaces are a fundamental requirement for any city because they promote a healthy lifestyle and preserve urban areas' aesthetic and ecological beauty. The current study examines urbanization's effect on Baghdad city vegetation and land surface temperature. The Normalized Difference Built-Up Index (NDBI), Normalized Difference Vegetation Index (NDVI), Normalized Difference Water Index (NDWI), and Land Surface Temperature (LST) over Baghdad were used to determine the relationship among urban areas, vegetation areas, water bodies, and land temperature. The Baghdad-vector-data from the Ge
... Show MoreBackground: Prophylaxis methods are used to mechanically remove plaque and stain from tooth surfaces; such methods give rise to loss of superficial structure and roughen the surface of composites as a result of their abrasive action. This study was done to assess the effect of three polishing systems on surface texture of new anterior composites after storage in artificial saliva. Materials and methods: A total of 40 Giomer and Tetric®N-Ceram composite discs of 12 mm internal diameter and 3mm height were prepared using a specially designed cylindrical mold and were stored in artificial saliva for one month and then samples were divided into four groups according to surface treatment: Group A (control group):10 specimens received no surfa
... Show MoreBackground: Alginate impression material is the irreversible hydrocolloid material that is widely used in dentistry. The contact time between alginate and gypsum cast could have a detrimental effect on the properties of the gypsum cast. The objective of this study is to evaluate the impact of various contact time intervals of Alginate impressions & type III dental stone on surface properties of stone cast. Materials and Methods: Time intervals tested were 1hour, 6 hours and 9 hours. Surface properties of stone cast evaluated were surface detail reproduction, hardness and roughness. Surface detail reproduction was determined using cylindrical brass test block in accordance with ISO 1563. Surface roughness was measured by profilometer
... Show More3-(4-hydroxyphenyl)-2-(3-(4-nitrobenzoyl) thioureido) propanoic acid (HNP) a new ligand was synthesized by reaction of Tyrosine with (4-Nitrobenzoyl isothiocyanate) by using acetone as a solvent. The prepared ligand (HNP) has been characterized by elemental analysis (CHNS), infrared (FT-IR), electronic spectral (Ultraviolet visible) and(1H,13C-Nuclear Magnetic Resonance) spectra. Some Divalent metal ion complexes of (HNP) were prepared and spectroscopic studies by Fourier transform infrared (FTIR), electronic spectral(UV-Vis), molar conductance, magnetic susceptibility and atomic absorption. The results measured showed the formula of six prepared complexes were [M (HNP)2] (M+2 = Manganese, Cobalt, Nickel, Znic, Cadmium and Mercury),from the
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