In the present study, multi-walled carbon nanotubes (MWCNTs) with outside diameters of< 8 nm and 20−30 nm were covalently functionalized with β-Alanine using a novel synthesis procedure. The functionalization process was proved successful using Raman spectroscopy, FTIR, and TEM. Utilizing the two-step method with ultrasonication, the MWCNTs treated with β-Alanine (Ala-MWCNTs) with weight concentrations of 0.025%, 0.05%, 0.075%, and 0.1% were dispersed in distilled water to prepare water-based nanofluids. The aqueous colloidal dispersions of pristine MWCNTs were unstable. While for Ala-MWCNTs and after> 50 days from preparation, higher colloidal stability was obtained up to relative concentration of 0.955 and 0.939 for the 0.075-wt% samples of Ala-MWCNTs < 8 nm and Ala-MWCNTs 20−30 nm, respectively. The measured values of thermal conductivity were in very good agreement with the model of Nan, Birringer, Clarke and Gleiter and increased as temperature, specific surface area (SSA), and weight concentration increased, up to 14.74% for Ala- MWCNTs < 8 nm and 12.29% for Ala-MWCNTs 20−30 nm. The viscosity increased as weight concentration increased, up 25.69% for 0.1-wt% Ala-MWCNTs 20−30 nm, and decreased with the increase in temperature. Since the matching between the measured values of viscosity and the classical models of Batchelor, Brinkman, and Einstein was bad, a correlation was developed and revealed good agreement. The density and specific heat decreased as temperature increased. As weight concentration increased, the density slightly increased up to 0.065% for Ala-MWCNT < 8 nm while the specific heat decreased down to 0.95% for Ala-MWCNTs 20−30 nm, in comparison with water. The equations of (Pak and Cho) and (Xuan and Roetzel) were in good agreement with the measured values of density and specific heat, respectively. The aqueous colloidal dispersions of Ala-MWCNTs that were prepared in this work displayed robust candidature as successful substitutes for the conventional heat transfer fluids in different engineering applications for enhanced thermal performance.
This work was carried to study the capability of activated alumina from bauxite compared with activated carbon adsorption capability to reduce the color content from Al-Hilla Textile Company wastewater. Six dyes were studied from two types(reactive and dispersed) namely (blue, red, yellow) from wastewater and aqueous solutions.
Forty eight experiments were carried out to study the effect of various initial conditions (bed height, flow rate, initial concentration, pH value, temperature, and competitive adsorption) on adsorption process.
The results showed that the adsorption process using activated carbon insured a good degree of color reduction reaching (99.7%) and was better than activated bauxite which reached (95%).
The aim of this research is to prepare a set of complexes with the general formula [M(HMB)n] , where M=VO (II) , Cr(III) and Cu(II) while n=2,3,2 respectively resulting from the reaction of anew ligand [N'-(2-hydroxy-3-methoxybenzyl)-4-methylbenzohydrazide] (HMB) derived from the reaction of the tow substances (4-methylbenzohydrazide and 2-hydroxy-3-methoxy benzaldehyde) with metal ions. The prepared compounds were identified by several spectroscopic methods such as Infrared, Nuclear Magnetic Resonance and Electronic Spectra. From the results of the measurements, it was suggested that the prepared complexes have different geometries such as square planar (Cu), square pyramidal (VO) and octahedral (Cr). DFT simulations backed up
... Show MoreBackground: Thymus vulgaris is a plant rich in essential oils acclaimed for the management of oxidative stress and inflammation in the organs. Meanwhile, the heavy metal lead is widely distributed in nature and continued exposure to lead acetate causes reduced fertility.Objectives: The present study aimed to investigate the effects of T. vulgaris on ovarian and uterine structural and functional characteristics in female rats exposed to lead acetate. Methods: Three groups of 18 mature Wistar albino female rats (Rattus norvegicus), 15 weeks old and weighing between 200 and 210 g, were established and handled for 60 days as follows: Group A (control group) received 0.5 mL of distilled water (DW) daily; group B received 5 mg/kg body weight (BW
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In this work, a novel technique to obtain an accurate solutions to nonlinear form by multi-step combination with Laplace-variational approach (MSLVIM) is introduced. Compared with the traditional approach for variational it overcome all difficulties and enable to provide us more an accurate solutions with extended of the convergence region as well as covering to larger intervals which providing us a continuous representation of approximate analytic solution and it give more better information of the solution over the whole time interval. This technique is more easier for obtaining the general Lagrange multiplier with reduces the time and calculations. It converges rapidly to exact formula with simply computable terms wit
... Show MoreThe objective of this research to analyze the effectiveness of monetary policy in achieving economic stability and growth for the period 2004-2011 ،This period of time saw a fundamental shift in monetary policy after the issuing new law the Central Bank of the full independence of the monetary authority ،This is Prompt the monetary authority to bring about a change in the philosophy and objectives and the tools used to achieve the desired goals ،Which give them the ability to control the size of the money supply and to achieve price stability Indeed، Monetary policy has been able to achieve the golden triangle of economic stability ،Consisted of staff، exchange rate stability and low and stable general level of prices
... Show MoreMulti-drug-resistant uropathogenic Escherichia coli (UPEC) is considered a significant challenge due to its ability to resist antibiotics and form biofilms. UPEC biofilm formers are well protected and largely inaccessible to antibiotics, which leads to persistent infections and evasion of the host immune system. Understanding how ciprofloxacin and trimethoprim/sulfamethoxazole affect biofilm formation is essential for improving treatment strategies for urinary tract infections (UTIs). A total of 76 UPEC isolates were obtained from Iraqi patients and identified using morphological and biochemical characteristics, as well as the Vitek®-2 Compact system. Minimum inhibitory concentrations (MICs) were determined using the Vitek®-2 system, whic
... Show MoreThe aim of this work is to evaluate some mechanical and physical
properties (i.e. the impact strength, hardness, flexural strength,
thermal conductivity and diffusion coefficient) of
(epoxy/polyurethane) blend reinforced with nano silica powder (2%
wt.). Hand lay-up technique was used to manufacture the composite
and a magnetic stirrer for blending the components. Results showed
that water had affected the bending flexural strength and hardness,
while impact strength increased and thermal conductivity decreased.
In addition to the above mentioned tests, the diffusion coefficient
was calculated using Fick’s 2nd law.
Abstract
The aim of this paper is to model and optimize the fatigue life and hardness of medium carbon steel CK35 subjected to dynamic buckling. Different ranges of shot peening time (STP) and critical points of slenderness ratio which is between the long and intermediate columns, as input factors, were used to obtain their influences on the fatigue life and hardness, as main responses. Experimental measurements of shot peening time and buckling were taken and analyzed using (DESIGN EXPERT 8) experimental design software which was used for modeling and optimization purposes. Mathematical models of responses were obtained and analyzed by ANOVA variance to verify the adequacy of the models. The resul
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