123 research outputs found

    Using of a New Carbon Nano Tube Version in Sheet Shape for Water and Wastewater Treatment

    Get PDF
    Removal of xylene (a toxic compound) from aqueous solution by modified multi wall carbon nano tubes (MWCNT) via silica as sheeted carbon nanotube (SCNT) was evaluated. The physicochemical properties of MWCNT such as structure and availability surface were improved due to convert tubes into sheets that cause significantly increase in xylene adsorption. The equilibrium amount (qe (mg/g)) in nano material's dose of 1g/l, xylene concentration of 10mg/l, contact time of 10min, and pH 7, for SCNT (qe 9.8 mg/g) was higher than single wall carbon nano tubes (SWCNT) (qe 9.2 mg/g) and MWCNT (qe 8.9 mg/g). It is concluded that sheeted carbon nanotube due to their large surface area improve performance of xylene adsorption. Also carbon nano tube (CNT) recycling by heating, showed better adsorption performance for recycled SCNT. A comparison study on xylene adsorption revealed that sheeted carbon nanotube has better xylene adsorption performance as compared to CNT, carbon and silica adsorbents. This suggests that the SCNT is an efficient adsorbent for xylene removal in environmental pollutions cleanup. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3508

    Analytical modeling of MHD flow over a permeable rotating disk in the presence of soret and dufour effects: Entropy analysis.

    Get PDF
    The main concern of the present article is to study steady magnetohydrodynamics (MHD) flow, heat transfer and entropy generation past a permeable rotating disk using a semi numerical/analytical method named Homotopy Analysis Method (HAM). The results of the present study are compared with numerical quadrature solutions employing a shooting technique with excellent correlation in special cases. The entropy generation equation is derived as a function of velocity, temperature and concentration gradients. Effects of flow physical parameters including magnetic interaction parameter, suction parameter, Prandtl number, Schmidt number, Soret and Dufour number on the fluid velocity, temperature and concentration distributions as well as entropy generation number are analysed and discussed in detail. Results show that increasing the Soret number or decreasing the Dufour number tends to decrease the temperature distribution while the concentration distribution is enhanced. The averaged entropy generation number increases with increasing magnetic interaction parameter, suction parameter, Prandtl number, and Schmidt number

    Study of nonlinear MHD tribological squeeze film at generalized magnetic reynolds numbers using DTM.

    Get PDF
    In the current article, a combination of the differential transform method (DTM) and Padé approximation method are implemented to solve a system of nonlinear differential equations modelling the flow of a Newtonian magnetic lubricant squeeze film with magnetic induction effects incorporated. Solutions for the transformed radial and tangential momentum as well as solutions for the radial and tangential induced magnetic field conservation equations are determined. The DTM-Padé combined method is observed to demonstrate excellent convergence, stability and versatility in simulating the magnetic squeeze film problem. The effects of involved parameters, i.e. squeeze Reynolds number (N1), dimensionless axial magnetic force strength parameter (N2), dimensionless tangential magnetic force strength parameter (N3), and magnetic Reynolds number (Rem) are illustrated graphically and discussed in detail. Applications of the study include automotive magneto-rheological shock absorbers, novel aircraft landing gear systems and biological prosthetics

    A numerical study for off-centered stagnation flow towards a rotating disc

    Get PDF
    AbstractIn this investigation, a semi-numerical method based on Bernstein polynomials for solving off-centered stagnation flow towards a rotating disc is introduced. This method expands the desired solutions in terms of a set of Bernstein polynomials over a closed interval and then makes use of the tau method to determine the expansion coefficients to construct approximate solutions. This method can satisfy boundary conditions at infinity. The properties of Bernstein polynomials are presented and are utilized to reduce the solution of governing nonlinear equations and their associated boundary conditions to the solution of algebraic equations. Graphical results are presented to investigate the influence of the rotation ratio α on the radial velocity, azimuthal velocity and the induced velocities. A comparative study with the previous results of viscous fluid flow in the literature is made

    Effects of Chlamydia trachomatis Infection on Fertility; A Case-Control Study.

    Get PDF
    BACKGROUND: Nowadays, Chlamydia trachomatis is known as a causative agent of infertility. Because of, asymptomatic nature of infection, many may suffer from its lasting complications such as infertility. This study was performed in Tehran during April 2007 to April 2008 to compare the prevalence of Chlamydia trachomatis infection in fertile and infertile women using ELISA and PCR methods. METHODS: Overall, 234 infertile and 223 pregnant women, as the fertile group, participated in this hospital-based case-control study. After completing an informed consent form and the questionnaire, first catch urine and blood sample were obtained for PCR and ELISA (IgG, IgM) tests, respectively. Logistic regression analysis was used to control possible confounding factors, and determine adjusted odds ratio of infertility due to the infection. RESULTS: PCR results revealed that 29 (12.4%) of the infertile and 19 (8.5%) of the fertile women were positive for C. trachomatis infection (p = 0.440). IgG was positive in 21 (9.0%) of the infertile and 11 (5.0%) in the fertile group (p = 0.093). IgM assays identified that 2 (0.9%) of the infertile and 4 (1.8%) of the fertile women were positive for the micro-organism (p = 0.375). CONCLUSION: We found no significant differences among fertile and infertile women for Chlamydia trachomatis infection. Nevertheless, molecular techniques which are more sensitive, more specific and non-invasive can be used to detect C. trachomatis infection

    Effect of different salinity concentration on different areas of the body skin of benni, Barbuss harpeyi

    Get PDF
    For this purpose, 144 specimens were studied in five healthy groups. The first group was the control group put in dechlorinated tap water and four respectively in the next group were kept with salinity 4ppt, 8ppt, 12ppt, 16ppt in the same condition. In days (1, 3, 7, 14, 21, 28) samples were collected from skin of head, ventral and lateral lines. Sections with 5- 6µm thickness were made and stained with PAS and H&E methods. In histometrical survey, epiderm thickness, numbering of club cells and goblet cells in 200 µm of epiderm length in any area, was investigated comparatively. The results showed that in different salinity concentrations, skin of head, ventral and lateral lines were influenced and changes in epiderm thickness, reduce the number of club cells and increase the number of goblet cells were demonstrated. These changes in different concentrations for each parameter, for significantly increased (p<0.05)

    Homotopy analysis of magnetohydrodynamic convection flow in manufacture of a viscoelastic fabric for space applications

    Get PDF
    Aerospace electro-conductive polymer materials are a new family of “smart” materials being deployed in many complex applications. The precision manufacturing of such processes to manipulate properties and enhance performance can exploit magnetohydrodynamic (MHD) control and simultaneous heat transfer (thermal processing). Motivated by these applications, we develop a model for laminar free convective flow of an incompressible and electrically-conducting viscoelastic fluid (Walters’ liquid B) over a continuously moving stretching surface embedded in a porous medium in the presence of strong radiative heat flux, as a simulation of magnetic smart fabric sheet processing. A heat generation/absorption term is included in the model. Darcy’s law is used to simulate porous media bulk drag effects. The stretching is assumed to be a linear function of the coordinate along the direction of stretching. Using similarity transformations, the governing partial differential equations are converted to nonlinear ordinary differential equations. The energy equation is further rendered into confluent hypergeometric form and then solved analytically for the prescribed surface temperature (PST) case and also for the Prescribed Boundary Surface Heat Flux (PHF) case, using Kummer’s function, subject to physically realistic boundary conditions. The momentum and energy equations are also solved using the semi-numerical homotopy analysis method (HAM), which contains the auxiliary parameter , permitting relatively easy adjustment and control of the convergence region of the series solution. This method provides an efficient approximate analytical solution with high accuracy, minimal calculation, and avoidance of physically unrealistic assumptions. HAM solutions are benchmarked with robust numerical shooting quadrature and found to correlate well. The influence of magnetic field on velocity and temperature profiles is studied via the Chandrasekhar number (Q). Furthermore detailed simulations are conducted for the influence of viscoelastic parameter (k1), Eckert number (E), radiation-conduction parameter (NR), Grashof number (Gr) and heat source/sink parameter () on the flow variables. The study finds applications in electro-conductive polymeric materials processing for aerospace fabric covers and other applications with demanding safety and protection requirements in smart materials synthesis

    The global burden of cancer attributable to risk factors, 2010–19: a systematic analysis for the Global Burden of Disease Study 2019

    Get PDF
    BACKGROUND: Understanding the magnitude of cancer burden attributable to potentially modifiable risk factors is crucial for development of effective prevention and mitigation strategies. We analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 to inform cancer control planning efforts globally. METHODS: The GBD 2019 comparative risk assessment framework was used to estimate cancer burden attributable to behavioural, environmental and occupational, and metabolic risk factors. A total of 82 risk–outcome pairs were included on the basis of the World Cancer Research Fund criteria. Estimated cancer deaths and disability-adjusted life-years (DALYs) in 2019 and change in these measures between 2010 and 2019 are presented. FINDINGS: Globally, in 2019, the risk factors included in this analysis accounted for 4·45 million (95% uncertainty interval 4·01–4·94) deaths and 105 million (95·0–116) DALYs for both sexes combined, representing 44·4% (41·3–48·4) of all cancer deaths and 42·0% (39·1–45·6) of all DALYs. There were 2·88 million (2·60–3·18) risk-attributable cancer deaths in males (50·6% [47·8–54·1] of all male cancer deaths) and 1·58 million (1·36–1·84) risk-attributable cancer deaths in females (36·3% [32·5–41·3] of all female cancer deaths). The leading risk factors at the most detailed level globally for risk-attributable cancer deaths and DALYs in 2019 for both sexes combined were smoking, followed by alcohol use and high BMI. Risk-attributable cancer burden varied by world region and Socio-demographic Index (SDI), with smoking, unsafe sex, and alcohol use being the three leading risk factors for risk-attributable cancer DALYs in low SDI locations in 2019, whereas DALYs in high SDI locations mirrored the top three global risk factor rankings. From 2010 to 2019, global risk-attributable cancer deaths increased by 20·4% (12·6–28·4) and DALYs by 16·8% (8·8–25·0), with the greatest percentage increase in metabolic risks (34·7% [27·9–42·8] and 33·3% [25·8–42·0]). INTERPRETATION: The leading risk factors contributing to global cancer burden in 2019 were behavioural, whereas metabolic risk factors saw the largest increases between 2010 and 2019. Reducing exposure to these modifiable risk factors would decrease cancer mortality and DALY rates worldwide, and policies should be tailored appropriately to local cancer risk factor burden

    Study of heat and mass transfer with Joule heating on magnetohydrodynamic (MHD) peristaltic blood flow under the influence of Hall effect

    No full text
    In this article, heat and mass transfer with Joule heating on magnetohydrodynamic (MHD) peristaltic blood under the influence of Hall effect is examined. Mathematical modelling is based on momentum, energy and concentration which are taken into account using ohms law. The governing partial differential equations are further simplified by neglecting the inertial forces and long wavelength approximations. Exact solutions have been presented for velocity, temperature and concentration profile. The influence of all the physical pertinent parameters is taken into account with the help graphs. It is found that Hartmann number and Hall parameter shows opposite behaviour on velocity, temperature and concentration profile. It is worth mentioning that pressure rise also depicts opposite behaviour for Hartmann number and Hall parameter. The present analysis is also presented for Newtonian fluid (α→0) as a special case for our study. It is observed that Hall Effect and magnetic field shows opposite behaviour on velocity and temperature profile. Temperature profile increases due to the increment in Prandtl number and Eckert number. Numerical comparison is also presented between the existing published results by taking α=0,M=0 as a special case of our study
    corecore