The effect of superficial gas velocity within the range 0.01-0.164 m/s on gas holdup (overall, riser and down comer), volumetric oxygen mass transfer coefficient, liquid circulation velocity was studied in an internal loop concentric tubes airlift reactor (working volume 45 liters). It was shown that as the u_sg increases the gas holdup and also the liquid circulation velocity increase. Also it was found that increasing superficial gas velocity lead to increase the interfacial area that increases the overall oxygen mass transfer coefficient. The hydrodynamic experimental results were modeled with the available equations in the literature. The predicted data gave an acceptable accuracy with the empirical data.

The final

Mechanical degradation hampers the practical usage of polymers for turbulent drag reduction
application. Mechanical degradation refers to the chemical process in which the activation energy of
polymer chain scission is exceeded by mechanical action on the polymer chain, and bond rupture
occurs. When a water-soluble polymer and surfactant are mixed in water solution, the specific structures
(aggregates) are formed, in which polymer film is formed around micelle. In this work, Xanthan gum (XG) –
Sodium lauryl ether sulfate (SELS) complex formation and its effect on percentage viscosity reduction
(%VR) was studied. It was found that SELS surfactant reduced the mechanical degradation of XG much
more efficiently than th

Mixed metal ligand complexes is reported with Curcumin (CUM) as a primary ligand and 1:10-phenanthroline (phen ) as secondary ligand. The structures of these complexes are confirmed by using FT-IR and UV- electronic spectroscopies, magnetic moments, melting points , molar conductivity measurements .and the metal % analysis revealed that the complexes analyze indicates a six coordinated as[M(CUM)( Phen)2]Cl, M=Mn (II), Co(II), Ni(II),Cu(II) ,Zn(II) , Cd(II) , Hg(II) and [M’ (CUM)( Phen)2]Cl2 M’= Cr(III) &. Fe(III). In-vitro antimicrobial studies on ( Curcumin and 1:10-phenanthroline ligands and mixed metal ligand complexes against {(Bacillus subtilis (G+) , Esherichia Coli (G-) and as well as antifungal activities against Candida albican

The research aims to test the effect of the behavioral factors (intangible) represented by an explanatory variable represented by organizational silence and a responsive variable of quality of Function life. The problem was the negative effects of the organizational silence on the morale of the employees and consequently their performance and the quality of function life. To collect the data and information needed to measure the two variables of research conducted in the health center / Sulaikh by taking a sample of (40) employees to test the hypotheses of research through the survey of their views, using statistical tools non parametric using the program. The most important recommendations were the establishment of training workshops fo

Whereas conventional methods of teaching history do not meet the sometimes purpose has suggested some educators strategies modern help to improve the level of students in the education process through activating prior knowledge and employed in positions of current learning, and focus attention on the points and the outstanding elements of the content and practice techniques Calendar criticof ideas and meanings and mental and linguistic activities used to verify the extent of reaching understanding.                                       &n

The current paper aims to identify potential factors associated with employees’ intentions to leave information and communication technology companies in Iraq. There is evident variability in the literature regarding these factors; hence, a factor analysis approach was employed to identify these factors within the surveyed environment. Due to the difficulty in precisely delineating the size of the research population, a purposive sampling method was employed to reach an appropriate number of respondents within the aforementioned companies. A total of 288 employees responded to the survey conducted via Google Forms. The test results revealed the presence of five primary factors associated with employees’ intentions to leave, name

The research is based on a statement of the effect and nature of the relationship of elements of promotional mix represented by (advertising, personal selling, sales promotion, public relations and direct marketing) as the independent variable in the dependent variable represented in the competitive advantage in the General Company for the manufacture of medicines and medical supplies Samarra. Analytical descriptive in the theoretical side, through the use of a number of literature from scientific sources (books, research and studies published in Arab and foreign magazines) was also relied on the methodology of the case study in the practical side, Data collection using the questionnaire tool, which was designed using the triangular Like