574 research outputs found

    MHD Flow of a Micropolar Fluid past a Stretched Permeable Surface with Heat Generation or Absorption

    Get PDF
    This work considers steady, laminar, MHD flow of a micropolar fluid past a stretched semi-infinite, vertical and permeable surface in the presence of temperature dependent heat generation or absorption, magnetic field and thermal radiation effects. A set of similarity parameters is employed to convert the governing partial differential equations into ordinary differential equations. The obtained self-similar equations are solved numerically by an efficient implicit, iterative, finite-difference method. The obtained results are checked against previously published work for special cases of the problem in order to access the accuarcy of the numerical method and found to be in excellent agreement. A parametric study illustrating the influence of the various physical parameters on the skin friction coefficient, microrotaion coefficient or wall couple stress as well as the wall heat transfer coefficient or Nusselt number is conducted. The obtained results are presented graphically and in tabular form and the physical aspects of the problem are discussed

    Synthesis and spectral studies of 5-[3-(1,2,4-triazolyl-azo]-2,4-dihydroxybenzaldehyde(TA)and its Schiff bases with 1,3-diaminopropane(TAAP)and 1,6-diaminohexane(TAAH).Their analytical application for spectrophotometric microdetermination of cobalt(II).

    Get PDF
    Cataloged from PDF version of article.The new azo compound 5-[3-(1,2,4-triazolyl-azo]-2,4-dihydroxy-benzaldehyde (TA) and its Schiff bases with 1,3-diaminopropane (TAAP) and 1,6-diaminohexane (TAAH) have been synthesized. The bands of diagnostic importance in the IR and the main signals in 1 H NMR spectra are assigned. The electronic absorption spectra in pure organic solvents of different polarity and in buffer solutions of varying pH are investigated. The quantitative description of the solvent effect on the electronic absorption spectra is studied and their acid ionization constants are determined. Also, a new simple and sensitive method for the spectrophotometric microdetermination of Co(II) using these compounds (TA, TAAP and TAAH) as new chromogenic reagents is established. The developed method is successfully used for the determination of trace amounts of cobalt in authentic samples and calculation of the distribution ratio of cobalt adsorbed on bentonite and kaolinite clay minerals. 2004 Elsevier Ltd. All rights reserved

    Fuzzy soft separation axioms in fuzzy soft topological spaces.

    Get PDF
    Fuzzy soft separation axioms was introduced by Mahanta and Das ([5]) using the definitions of a `fuzzy soft point' and `the complement of a fuzzy soft point is a fuzzy soft point', and `distinct of fuzzy soft points' in there sense.  In this paper we, introduce fuzzy soft separation axioms in terms of the modified definitions of a `fuzzy soft point', the complement of a fuzzy soft point is a fuzzy soft set' and `distinct of fuzzy soft points'([7]). Also, we study some of their properties. Finally, we discuss fuzzy soft topological property for such spaces.                                                          &nbsp

    TMS excitability study in essential tremor: Absence of gabaergic changes assessed by silent period recordings

    Get PDF
    BACKGROUND: Essential tremor (ET) is thought to emerge from activity in a distributed cerebello-thalamo-cortical network. It has been proposed that the network goes into oscillation because of abnormal GABAergic inhibitory transmission. OBJECTIVE: To test this idea by investigating GABAergic circuitry in motor cortex using transcranial magnetic stimulation (TMS). METHODS: Motor cortex excitability was examined using TMS in 21 patients with essential tremor and in 20 control subjects. Resting and active motor threshold (RMT, AMT) and input-output curves examined corticospinal excitability. Contralateral silent period (cSP) at a different range of stimulation intensities, and the ipsilateral silent period (iSP) using a stimulus intensity of 150% RMT were used as measures of GABAergic function. RESULTS: RMT and AMT were significantly lower in patients than controls and patients had a steeper I/O curve. However, there were no significant differences in either cSP at different intensities or in iSP. CONCLUSION: We found no evidence in favour of the GABA hypothesis in ET

    The Computational Techniques Developed to Analyze DNA Gel Images

    Full text link
    The analysis of gel electrophoresis images is very crucial for molecular biologists to comprehend and interpret their experimental results. Thus, enhancing current mathematical methods and developing new accurate ones is very important and challenging task for bioinformaticians. For example, enhancing the commonly used mathematical method in gel analysis known as "Fitting method estimation" and proposing a new efficient method entitled "Ruler estimation" for preprocessing a given image and detecting lanes and bands automatically. Both mathematical methods implemented in our newly developed software. Three mathematical models namely, linear, quadratic and cubic fitting are tested for the accuracy of detecting the bands and lanes in the gel image to determine the best fitting model. A friendly user interface is developed for this new program using MATLB GUI to extract useful bimolecular information accurately and automatically. The new software has the ability to manually add or delete any band(s) and estimate the size of any unknown band(s) on the gel. Moreover, the similarity and (dis)similarity between lanes "samples" are estimated based on comparing the numbers and sizes of bands to generate a phylogram tree

    Diagrama ternario de sistemas de extracción proteínas/disolvente: Proteínas de sésamo, soja y altramuz

    Get PDF
    Solvent extraction as a method of extracting protein from oilseed meals offers the advantage of higher efficiency. Unfortunately, the published literature points to the gap in the work concerned with the necessary equilibrium diagram to design due process equipment for such extracts. Initiated by this lack of basic knowledge, the present study has been undertaken to provide the equilibrium data for three different ternary systems, namely: sesame protein / sodium hydroxide solution system, soybean protein / sodium hydroxide solution system and lupine protein / sodium hydroxide solution system. These oilseed meals were selected because of their high protein content (53.4 %, 46.2 % and 42.3 % protein, respectively). The study also concentrated on the evaluation of the major parameters affecting the extraction process, i.e. the normality of the sodium hydroxide solution used as extracting solvent and the initial oilseed solvent to meal feeding ratio. The results obtained indicate that the best normality of sodium hydroxide solution used for extracting soybean and lupine protein is 0.02N, while 0.04N solution is required for extracting sesame protein. Also, operating at a liquid to solid feed ratio of 30:1 and 50:1 for soybean, sesame and lupine, respectively, is enough to reach a high protein extract. Correlations were presented for each locus of under flow compositions, graphically acquired, and the data are compared with those calculated by analytical solutions.La extracción con disolventes es un método de extracción de proteínas de las harinas de semillas oleaginosas que ofrece la ventaja de su elevada eficacia. Desafortunadamente, la bibliografía coincide en el vacío existente con respecto a los diagramas de equilibrio necesarios para el diseño de los equipos adecuados. Debido a esta falta de conocimientos, el presente estudio se ha llevado a cabo para obtener datos de tres sistemas ternarios: sistema proteína de sésamo / disolución de hidróxido sódico, sistema proteína de soja / disolución de hidróxido sódico y sistema proteína de altramuz / disolución de hidróxido sódico. Dichas harinas de semillas oleaginosas se seleccionaron por su alto contenido en proteínas (53,4 %, 46,2 % y 42,3 %, respectivamente). El estudio también contempló la evaluación de los parámetros más importantes que afectan al proceso de extracción, es decir, la normalidad de la disolución de hidróxido sódico utilizada como agente de extracción y la relación inicial disolvente: harina. Los resultados obtenidos indican que la mejor normalidad de la disolución de hidróxido sódico usada para extraer la proteína de la harina de soja y altramuz es 0,02N mientras que para la de sésamo es 0,04N. Asimismo operando con una relación líquido/sólido de 30:1 y 50:1 para soja y sésamo o altramuz respectivamente, se consiguen extractos con alto contenido en proteínas. Se han obtenido correlaciones gráficamente para diferentes puntos del sistema, y los datos se han comprobado con los calculados analíticamente

    On pairwise super continuous mappings in bitopological spaces

    Get PDF
    The aim of this paper is to define and study super-continuous mappings and some other forms of continuity such as strong continuity, perfect continuity and complete continuity in bitopological spaces and investigate the relations between these kinds of continuity and their effects on some kinds of spaces

    Photodegradation of microcystin-LR using visible light-activated C/N-co-modified mesoporous TiO 2 photocatalyst

    Get PDF
    Microcystin-LR (MC-LR), a potent hepatotoxin produced by the cyanobacteria, is of increasing concern worldwide because of severe and persistent impacts on humans and animals by inhalation and consumption of contaminated waters and food. In this work, MC-LR was removed completely from aqueous solution using visible-light-active C/N-co-modified mesoporous anatase/brookite TiO 2 photocatalyst. The co-modified TiO 2 nanoparticles were synthesized by a one-pot hydrothermal process, and then calcined at different temperatures (300, 400, and 500 °C). All the obtained TiO 2 powders were analyzed by X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscope (TEM), specific surface area (SSA) measurements, ultraviolet-visible diffuse reflectance spectra (UV-vis DRS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, and photoluminescence (PL) analysis. It was found that all samples contained mixed-phase TiO 2 (anatase and brookite), and the content of brookite decreased with an increase in calcination temperature, as well as the specific surface area and the content of non-metal elements. The effects of initial pH value, the TiO 2 content, and MC-LR concentration on the photocatalytic activity were also studied. It was found that the photocatalytic activity of the obtained TiO 2 photocatalysts declined with increasing temperature. The complete degradation (100%) of MC-LR (10 mg L -1 ) was observed within 3 h, using as-synthesized co-modified TiO 2 (0.4 g L -1 ) at pH 4 under visible light. Based on the obtained results, the mechanism of MC-LR degradation has been proposed. © 2019 by the authors

    Computational and experimental elucidation of the boosted stability and antibacterial activity of ZIF-67 upon optimized encapsulation with polyoxometalates

    Get PDF
    Water microbial purification is one of the hottest topics that threats human morbidity and mortality. It is indispensable to purify water using antimicrobial agents combined with several technologies and systems. Herein, we introduce a class of nanosized metal organic framework; Zeolitic imidazolate framework (ZIF-67) cages encapsulated with polyoxometalates synthesized via facile one-step co-precipitation method. We employed two types of polyoxometalates bioactive agents; phosphotungstic acid (PTA) and phosphomolybdic acid (PMA) that act as novel antibacterial purification agents. Several characterization techniques were utilized to investigate the morphological, structural, chemical, and physical properties such as FESEM, EDS, FTIR, XRD, and N₂ adsorption/desorption isotherms techniques. The antibacterial assessment was evaluated using colony forming unit (CFU) against both Escherichia coli and Staphylococcus aureus as models of Gram-negative and Gram-positive bacteria, respectively. The PTA@ZIF-67 showed higher microbial inhibition against both Gram-positive and Gram-negative bacteria by 98.8% and 84.6%, respectively. Furthermore, computational modeling using density functional theory was conducted to evaluate the antibacterial efficacy of PTA when compared to PMA. The computational and experimental findings demonstrate that the fabricated POM@ZIF-67 materials exhibited outstanding bactericidal effect against both Gram-negative and Gram-positive bacteria and effectively purify contaminated water
    corecore