Esterification reaction is most important reaction in biodiesel production. In this study, oleic acid was used as a suggested feedstock to study and simulate production of biodiesel. Batch esterification of oleic acid was carried out at operating conditions; temperature from 40 to 70 °C, ethanol to oleic acid molar ratio from 1/1 to 6/1, H2SO4 as the catalyst 1 and 5% wt of oleic acid, reaction time up to 180 min. The optimum conditions for the esterification reaction were molar ratio of ethanol/oleic acid 6/1, 5%wt H2SO4 relative to oleic acid, 70 °C, 90 min and conversion of oleic 0.92. The activation energy for the suggested model was 26625 J/mole for forward reaction and 42189 J/mole for equilibrium constant. The obtained results simulated to other types of reactors with different operating conditions using reactop cascade package. The conversion of oleic acid of simulation results at optimum operating conditions was 0.97 for isothermal batch and plug flow reactors, 0.67 for isothermal CSTR, while the conversions of oleic acid in the adiabatic mode were 0.82, 0.40, 0.74 for batch, CSTR, PFR reactors respectively.
Background: The aim of this study was to evaluate the shear bond strength (SBS) and adhesive remnant index (ARI) of different orthodontic adhesive systems after exposure to aging media (water storage and acid challenge). Materials and methods: Eighty human upper premolar teeth were extracted for orthodontic purposes and randomly divided into two groups (40 teeth each): the first group in which the bonded teeth were stored in distilled water for 30 days at 37°C, and the second group in which the bonded teeth were subjected to acid challenge. Each group was further subdivided into four subgroups (10 teeth each) according to the type of adhesive system that would be bonded to metal brackets: either non-fluoride releasing adhesive (NFRA),
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ABSTRACT Background: Color changes that are detectable to human eye can affect the esthetic appearance of ceramic veneers. The purpose of this study was to evaluate and compare the effect of artificial accelerated aging on the color of ceramic veneers cemented with different resin cements. Materials and Methods: Sixty discs were prepared with 0.5 mm thickness, 30 discs made from IPS e.max press (Ivoclar Vivadent) and 30 discs were made from VITA Enamic (VITA Zahnfabrik). The discs were cemented with three resin cements: Variolink Veneer MV 0 shade (Ivoclar Vivadent), Rely X veneer Translucent shade (3M ESPE) and NX3 Nexus Clear shade (Kerr Corporation) with 0.1 mm thickness. The spectrophotometer Easyshade Advance was used to measure the co
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Two new ligands Na2[ H3B (BDIA)].0.05H2O (L1)(BDIA = 1-Boranyl-2,3-
Dihydro-1H-Indol-3-yl)]Acetic Acid and Na3[H2B(BDIA)2].0.3H2O.0.3CH3Ph (L2)
were synthesized by reaction of NaBH4 with indole -3- acetic acid (IAA) . The
coordination properties of ligands were studied with Co(II) , Ni(II) , Cu(II) and
Pt(IV) ions. Characterization and structural aspects of the prepared compounds were
elucidated by 1HNMR, FTIR electronic spectra, magnetic susceptibility, elemental
and metal analysis, thermal analysis (TG & DTG) and conductivity measurements.
The obtained data for metal complexes suggested square planar geometry for
copper complexes, octahedral geometry for nickel and platinium complexes and
tetrahedral geom
This study has been carried out in the animal field of the college of agricultural engineering sciences, university of Baghdad, for the period from 12/15/2021 to 1/26 /2022 for 42 d, to investigate the effect of adding different levels of ellagic acid to the diet of broilers, on some physiological characteristics & oxidation indicators in meat compared to vitamin C in meat, 225 Ross 308 chicks were used, divided randomly to five treatments such us: T1: control group without additives to diet, & the other T2, T3, T4 was added ellagic acid (
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Objective: To study the protective eff ects of cinnamic acid on dextran sodium sulfate (DSS) induced ulcerative colitis (UC) in mice. Materials and methods. Forty adult male mice were randomLy divided into fi ve groups, control group, an induction group received 3% DSS in drinking water for 7 consecutive days. Two treatment groups received oral suspension of cinnamic acid 50 and 25 mg/kg, respectively and 3% DSS in drinking water, for 7 consecutive days. The fi nal group received oral suspension of cinnamic acid 50 mg/kg for the latter 7 days without DSS in drinking water. All the animals were euthanized on day eight. The colon of animals was extracted and divided into two sections, the middle was homogenized and biochemically analy
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