In the present work, steady, laminar natural convection in nonrectangular enclosures is analyzed numerically with and without fin. Vertical walls insulated while horizontal walls maintained isothermal at different temperature and the fin was placed on horizontal surface. The length of fin was equal (B/L=0.22, 0.44 and 0.66) and thickness of fin was constant. Various parameters are studied: Rayleigh number (from 104 to 107 ), Prandtl number (0.7), number of fin change from (1-3) and aspect ratio (H/L= 0.15 to 0.5). The problem is formulated in terms of the vorticity-stream function procedure. A numerical solution based on program in Fortran 90 with Tec plot program. The finite difference method is used. Streamlines and isotherms are presented for different values of parameters studied. A Nusselt number correlation is derived by using program (DGA v1.00) and mean Nusselt numbers on hot walls are also calculated at different cases. The results show the mean Nusselt numbers decreases with increasing aspect ratio (H/L).Also, predictions reveal a decrease in heat transfer in the presence of fins. The results of the calculations are compared with the previous works and it showed a good agreement.
Natural bitumen (NB) is a highly precious material and has drawn increasing attention due to its unique properties, especially since it is available in large quantities and has been used in limited fields. In this research, the exploitation of NB from sulfur springs as an alternative energy resource in the production of asphalt pavement is evaluated. It can be concluded from the experimental results that the chemical composition and surface morphology of NB samples are different from those of base asphalt. Besides, the rheological properties of virgin NB are not sufficient for paving work. To overcome this obstacle, NB from five different springs is modified with limestone filler (LSF) to enhance its properties. LSF is a natural material an
... Show MoreA biostimulant is any microorganism or substance used to enhance the efficiency of nutrition, tolerance to abiotic stress and/or quality traits of crops, depending on its contents from nutrients. Plant biostimulants like honey bee (HB) and silymarin (Sm) are a strategic trend for managing stressed crops by promoting nutritional and hormonal balance, regulating osmotic protectors, antioxidants, and genetic potential, reflecting plant growth and productivity. We applied diluted honey bee (HB) and silymarin-enriched honey bee (HB- Sm) as foliar nourishment to investigate their improving influences on growth, yield, nutritional and hormonal balance, various osmoprotectant levels, different components of antioxidant system, and genetic p
... Show MorePulsatile drug delivery systems are time-controlled dosage forms which are designed to release the active pharmaceutical ingredient after a predetermined lag time to synchronize the disease circadian rhythm. A migraine shows circadian rhythm with a marked increase in attacks between 6 a.m. and 8 a.m.
Sumatriptan is a selective agonist at serotonin (5-Hydroxy tryptamine1 (5-HT1))receptors, is an effective treatment for acute migraine attacks.
The aim of this work is to prepare time-controlled press-coated tablet with a lag time of 5.45 hrs.
Six formulas of fast dissolving core tablets and three formulas of press-coated tablets were prepared by using direct compression method using different variables to prepa
... Show MoreAbstract
This research aims to study and improve the passivating specifications of rubber resistant to vibration. In this paper, seven different rubber recipes were prepared based on mixtures of natural rubber(NR) as an essential part in addition to the synthetic rubber (IIR, BRcis, SBR, CR)with different rates. Mechanical tests such as tensile strength, hardness, friction, resistance to compression, fatigue and creep testing in addition to the rheological test were performed. Furthermore, scanning electron microscopy (SEM)test was used to examine the structure morphology of rubber. After studying and analyzing the results, we found that, recipe containing (BRcis) of 40% from th
... Show MoreThis study was aimed to synthesis Ag2O nanoparticles (N.P.s) utilizing the Ginger plant (Zingiber officinale) extract. As catalysts for pyran derivatives formation employing a three-component coupling reaction among aromatic and aliphatic aldehydes, malononitrile, and dimedone. The nanoparticles exhibit robust catalytic activity with high productivity. Results revealed that Ag2O NPs improved various vital features, like higher yields, reaction time, simple chemical separation, catalytic economic efficiency, and quick process. This study aimed to cyclize heterocyclic compounds to provide new hetero compounds applying nano-oxides obtained from natural (unmanufactured) sources and used in several medical, pharmaceutical, and industrial
... Show MoreBackground: Antimicrobial prescribing patterns have an important role in the emergence of resistance, and community pharmacists have a substantial influence on this issue. Objective: To assess community pharmacists' behaviors and attitudes toward antimicrobial dispensing, determine their proportions and categories, and examine the underlying rationales for this practice. Methods: A descriptive cross-sectional survey of community pharmacists in Iraq was conducted from June to August 2023, using a self-administered validated questionnaire. The attitudes, practices, and motivations driving the distribution of antimicrobials without a prescription (AWP) were explored in three areas. Results: A sizable proportion (61.6%) of respondents rejected
... Show MoreThe specific activities of the natural radionuclides U-238 and Th-
232 and K-40 in 14 soil samples collected from different sites from
AL-Mustansiriyah university at two depths (topsoil "surface" and
20cm depth) were be investigated using gamma ray spectrometer
3"x3" NaI(Tl) scintillation detector.
The analysis of the energy spectra of the soil samples show that
these samples have specific activities ranging with (16.08-51.11)
Bq/kg for U-238, (14.79-52.29) Bq/kg for Th-232 and (191.08-
377.64) Bq/kg for K-40, with an average values of 29.37, 34.14 and
289.62 Bq/kg for U-238, Th-232, k-40 respectively. The radiation
hazard parameters of the natural radionuclides; radium equivalent
activity (Raeq), gamma a
In this paper, a polymer-based composite material was prepared by hand Lay-up method consisting of epoxy resin as a base material reinforced by magnesium oxide powder once and silicon dioxide powder again and with different weight ratios (3, 6, 9 and 12) wt %. The three-point bending test was performed in normal conditions and after immersion in sulfuric acid. The results showed that the bending value decreased with the increase of the weighted ratio of the reinforcement material (MgO, SiO2). The Bending of samples reinforced by SiO2 was found to be less than the bending of samples reinforced by particles (MgO). For example, the bending of the SiO2 sample (0.32 mm) at the weighted ratio (3%) and for the MgO (0.18mm) sample at the weight
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