This work deals with kinetics and chemical equilibrium studies of esterification reaction of ethanol with acetic acid. The esterification reaction was catalyzed by an acidic ion exchange resin (Amberlyst- 15) using a batch stirred tank reactor. The pseudo-homogenous and Eley-Rideal models were successfully fitted with experimental data. At first, Eley-Rideal model was examined for heterogeneous esterification of acetic acid and ethanol. The pseudo-homogenous model was investigated with a power-law model. The apparent reaction order was determined to be (0.88) for Ethanol and (0.92) for acetic acid with a correlation coefficient (R2) of 0.981 and 0.988, respectively. The reaction order was determined to be 4.1087x10-3 L0.8/(mol0.8.min) with R2 of 0.954. The adsorption constants of acetic acid and ethanol were calculated as 0.023 and 0.044 L/mol, respectively and the lumped reaction constant were determined to be 5*10-4 L2/gcat.mol.min. The results of the reaction kinetic study show that the high acetic acid/ethanol molar ratio was favored. The maximum conversion of 70 % was obtained at 70°C for acetic acid/ethanol molar ratio of 4.
Gaslift reactors are employed in several bioapplications due to their characteristics of cost-effectiveness and high efficiency. However, the nutrient and thermal gradient is one of the obstacles that stand in the way of its widespread use in biological applications. The diagnosis, analysis, and tracking of fluid paths in external draft tube gaslift bioreactor-type are the main topics of the current study. Several parameters were considered to assess the mixing efficiency such as downcomer-to-rizer diameter ratio (Ded/Dr), the position of the diffuser to the height of bioreactor ratio (Pd/Lr), and gas bubble size (Db). The multiple regression of liquid velocity indicates the optimal setting: Ded/Dr is (0.5), Pd/Lr is (0.02), and Db
... Show MoreIn this study, generation of elliptical gears with different teeth profiles of crowned involute, double circular arc (DCA), and combined (crowned involute with DCA) has been developed. The resulting mathematical equations have been computerized and feed to CNC end mill machine to manufacture elliptical gear models with different profiles. These models are investigated in plane polariscope to show the resulting stresses under certain load. Comparison of photo-elastic stress results shows that combined elliptical gears with DCA side as a loaded side have a minimum resulting contact stress with a reduction percentage of 40% compare with contact stresses in counterpart elliptical gear of involute profile (which is commonly u
... Show More The vast majority of EC applications are the web-based deployed in 3-tire Server-Client environment, the data within such application often resides within several heterogeneous data sources. Building a single application that can access each data sources can be a matter of challenging; this paper concerns with developing a software program that runs transparently against heterogeneous environment for an EC-application.
The role of the public sector- Investment customizations- economic embargo - The role of the private sector - Coexistence between the public and private sectors - Ratio of growth
We focus on studying the dynamics of bulk semiconductor optical amplifiers and their effects on the saturation region for short pulse that differ, however there is the same unsaturated gain for both dynamics. Parameters like current injection, fast dynamics present by carrier heating (CH), and spectra hole burning (SHB) are studied for regions that occur a response to certain dynamics. The behavior of the saturation region is found to be responsible for phenomena such as recovery time and chirp for the pulse under study.
At the last two decades , The environment has witnessed tremendous changes in many fields with the huge competition , various technological development and customer satisfaction , that are reflected in economic units a doption for lean production system .
Lean Accounting that has appeared as aresponse for changes occurred of economic units adoption for lean accounting system instead of wide production system : through it management of economic units has been changed from management by top departments into management by value flows : has provide new method for accounting costs according to value flow
... Show MoreThe media: ((Providing people with the right news, audio information, and constant facts that help them form a correct opinion in an incident or a problem, this opinion gives an objective expression of the mentality of the audience, their trends and tendencies). The German scientist Autogroot defines it as "the objective expression of the mentality of the audience, their spirit, their tendencies, and their trends at the same time." Whereas for "Aristotle", (Language) is a specific verbal system created as a result of an agreement between the members of the human group somewhere )). It is a symbol of thought, and a difference between humans and animals. Pronunciation and thought for “Aristotle” are intertwined: without pro
... Show MoreLaboratory experience in Iraq with cold asphalt concrete mixtures is very limited. The design and use of cold mixed asphalt concrete had no technical requirements. In this study, two asphalt concrete mixtures used for the base course were prepared in the laboratory using conventional cold-mixing techniques to test cold asphalt mixture (CAM) against aging and moisture susceptibility. Cold asphalt mixtures specimens have been prepared in the lab with cutback and emulsion binders, different fillers, and curing times. Based on the Marshal test result, the cutback proportion was selected with the filler, also based on the Marshal test emulsion. The first mixture was medium setting cationic emulsion (MSCE) as a binder, hydrate
... Show MoreBackground: Humeral diaphyseal fracture usually
heals with closed methods but when nonunion
develops then it needs surgical intervention in the
form of plating and bone grafting, intramedulary
nailing (open or closed simple or interlocking nails)
and external fixators (circular or one plane fixator).
In our unit we treated non union humeral
diaphyseal fracture with plating and bone grafting
shortening of fracture ends up to 4 to 5cm when
needed. Methods: This study was conducted at
Orthopaedic Department of AL-Sadar General
Hospital from January 2004 till December2005 .
We included 20 cases with atrophic non-union in
12(60%) and hypertrophic non-union in 8 (40%)
patients. All atrophic non-union w