Esterification considers the most important reaction in biodiesel production. In this study, oleic acid was used as a suggested feedstock in order to study and simulate production of biodiesel. The batch esterification reaction of oleic acid was carried out at various operating conditions; temperature from 40 to 70 °C, ethanol to oleic acid molar ratio from 3/1 and 6/1 and a reaction time up to 180 min.
The catalyst used was prepared NaY zeolite, which is added to the reaction mixture as 2, 5 and 10 wt.% of oleic acid.
The results show that the optimum conditions, gives 0.81 conversion of oleic acid, were 6/1 molar ratio of ethanol/oleic acid, 5 wt.% NaY relative to initial oleic acid, 70°C and 60 minutes. The activation energy of the suggested model was 42692 J/mole for forward reaction and 17218 J/mole for backward reaction.
Objective: Conventional approaches for disinfection, including spraying and immersion, resulted in only surface disinfection of impressions. As a result, self-disinfecting impression materials incorporated with antimicrobial compounds require more extensive studies. The incorporation of a disinfectant into irreversible hydrocolloid impression materials could eliminate the need for the disinfection step by conventional approaches, including spraying and immersion which only result in surface disinfection of impressions. The study was aimed to investigate the effect of incorporation of hypochlorous acid in irreversible hydrocolloid materials on antimicrobial efficiency, detail reproduction, and dimensional stability. Materials and
... Show MoreBackground: human paillomavirus infections (genital warts) are the most frequent sexually transmitted viral infections. a wide range of treatment options is available with different efficacy.
Objective: To evaluate the efficacy of podophyllin, trichloracetic acid (TCA) in the treatment of genital warts and side effects of them.
Subjects and methods: a total of sixty patients with genital warts were randomly selected, 30 in each group, in the Department of Dermatology, medical city for a Duration of 11 months from January 2009 to December 2009 treated with 35 % podophyllin in the tincture of benzoin or 50% TCA) .Forty-eight patients were followed up for three months.
Results: wart
... Show MoreMyrtle plant was washed, dried, and powdered after harvesting to produce a fine powder used in water treatment. An alcoholic extract was created from the myrtle plant using ethanol, which was then analyzed using GC-Mass, Fourier Transform Infrared spectroscopy, and ultraviolet-visible spectroscopy to identify the active components. Zinc nanoparticles were created using alcoholic extract. FT-IR, UV-Vis, SEM, EDX, and TEM were used to characterize zinc nanoparticles. Using a continuous processing procedure, zinc nanoparticles with myrtle extract and powder were employed to clean polluted water containing pesticides and antibiotic. First, 2 g of zinc nanoparticles was mixed with 20 ml of polluted water and the result was (Tetra 44%, Levo 32%),
... Show MoreA numerical simulation is made on the thermal lensing effect in an laser diode end-pumped Nd:YAG laser rod. Based on finite element method (FEM), the laser rod temperature distribution is calculated and the focal length is deduced for a Gaussian and super-Gaussian pump beam profiles.
At the pump power of 20W, the highest temperature located at the center of end-pumped face was 345K, and the thermal lens focal length was 81.4mm along the x-z axis.
The results indicate that the thermal lensing effect sensitively depend on the pump power, waist radius of the pump beam and the pump distribution in a laser rod geometry.
The coagulation and flocculation process using coated magnetic nanoparticles is considered one of the effective technologies for turbidity removal. This study investigates an application of magnetic nanoparticles coated with citric acid in the coagulation and flocculation process on Tigris River water in Baghdad, Iraq. Magnetic nanoparticles (MNP1) were synthesized by the co-precipitation method and coated with citric acid (MNP2). The prepared MNP1 and MNP2 were characterized by XRD, FTIR, AFM, FE-SEM, EDS, and zeta potential analysis. For coagulation process, the effect of different types of coagulants (alum, FeCl3, MNP1, MNP2), coagulant dosage (10–110 mg/l), and initial pH (3–9) were examined in this work. The best coagulant was MNP2
... Show MoreZinc sulfide (ZnS) thin films were deposited on glass substrates using pulsed laser deposition technique. The laser used is the Q-switched Nd: YAG laser with 1064nm wavelength and 1Hz pulse repetition rate and varying laser energy 700mJ-1000mJ with 25 pulse. The substrate temperature was kept constant at 100°C. The structural, morphological and optical properties of ZnS thin films were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscope (AFM) and UV-VIS spectrophotometer.
Tin Selenide (SnSe) Nano crystalline thin films of thickness 400±20 nm were deposited on glass substrate by thermal evaporation technique at R.T under a vacuum of ∼ 2 × 10− 5 mbar to study the effect of annealing temperatures (as-deposited, 100, 150 and 200) °C on its structural, surface morphology and optical properties. The films structure was characterized using X-ray diffraction (XRD) which showed that all the films have polycrystalline in nature and orthorhombic structure, with the preferred orientation along the (111) plane. These films was synthesized of very fine crystallites size of (14.8-24.5) nm, the effect of annealing temperatures on the cell parameters, crystallite size and dislocation density were observed.
... Show MoreUndoped and Iodine (I)–doped chrome oxide (Cr2O3)thin films have been prepared by chemical spray pyrolysis technique at substrate temperatures(773K) on glass substrate. Absorbance and transmittance spectra have been recorded as a function of wavelength in the range (340-800 nm) in order to study the optical properties such as reflectance, Energy gap of allowed direct transition, extinction coefficient refractive index, and dielectric constant in real and imagery parts all as a function of wavelength. It was found that all the investigated parameters affect by the doping ratios.
Zinc oxide thin films were deposited by chemical spray pyrolysis onto glass substrates which are held at a temperature of 673 K. Some structural, electrical, optical and gas sensing properties of films were studied. The resistance of ZnO thin film exhibits a change of magnitude as the ambient gas is cycled from air to oxygen and nitrogen dioxide