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Raney-Ni catalyzed conversion of levulinic acid to 5-methyl-2-pyrrolidone using ammonium formate as the H and N source
No full textRenewable biomass based levulinic acid was converted to 5-methyl-2-pyrrolidone in 94% yield by a Raney-Ni catalyzed process using ammonium formate in aqueous medium and heating at 180 °C for 3 h. The Raney-Ni could be reused for four catalytic cycles with about 10% loss in catalytic activity. In a similar reaction levulinic acid could be converted 1-substituted-5-methyl-2-pyrrolidones in 90–95% yield by using a mixture of formic acid and the corresponding primary amine
Renewable polymers: Synthesis and characterization of poly(levulinic acid–pentaerythritol)
No full textThe analysis of M/M/1 queue with working vacation in fuzzy environment
Get PDFThis study investigates the FM/FM/1 queue with working vacation. For this fuzzy queuing model, the researcher obtains some performance measure of interest such as the regular busy period, working vacation period, stationary queue length and waiting time. Finally, numerical results are presented to show the effects of system parameters
Some New Discretization Methods with Application in Reliability
Get PDFDeriving discrete analogues (Discretization) of continuous distributions has drawn attention of researchers, in recent decades. Discretization has been playing a key role in modeling life time data because in real world, most of original life time data are continuous while they are discrete in observation. In this paper, we introduce three new two-stage composite discretization methods to meet the need of fitting discrete-time reliability and survival data sets. All three proposed methods consist of two stages where using construction a new continuous random variable by underlying continuous random variable in the first stage and so based on maintaining hazard rate function in the second stage, discretization do. In the first two methods, hazard rate functions of discrete analogues are decreasing and increasing, respectively, and in the third method with this condition that there is maximum of underlying continuous distribution pdf, hazard rate function of discrete analogue and pdf of its continuous version have the opposite behavior. Therefore hazard rate functions of discrete analogues obtained by this method can be increasing, U-shaped or modified unimodal. Notice that an important advantage of proposed methods is that obtained discrete analogues have monotonic and non-monotonic hazard rate functions. Finally, these proposed methods have been used for approximating the reliability of an important engineering item where exact determination of survival probability is analytically intractable. We then proceed to a comparative study between the discretizing method that retains the form of survival function and ours that indicates our methods are in no way less efficient
Conformable Derivative Operator in Modelling Neuronal Dynamics
Get PDFThis study presents two new numerical techniques for solving time-fractional one-dimensional cable differential equation (FCE) modeling neuronal dynamics. We have introduced new formulations for the approximate-analytical solution of the FCE by using modified homotopy perturbation method defined with conformable operator (MHPMC) and reduced differential transform method defined with conformable operator (RDTMC), which are derived the solutions for linear-nonlinear fractional PDEs. In order to show the efficiencies of these methods, we have compared the numerical and exact solutions of fractional neuronal dynamics problem. Moreover, we have declared that the proposed models are very accurate and illustrative techniques in determining to approximate-analytical solutions for the PDEs of fractional order in conformable sense
A de Casteljau Algorithm for Bernstein type Polynomials based on (p; q)-integers
Get PDFIn this paper, a de Casteljau algorithm to compute (p; q)-Bernstein Bezier curves based on (p; q)- integers are introduced. The nature of degree elevation and degree reduction for (p; q)-Bezier Bernstein functions are studied. The new curves have some properties similar to q-Bezier curves. Moreover, we construct the corresponding tensor product surfaces over the rectangular domain (u; v) in [0; 1] x [0; 1] depending on four parameters. De Casteljau algorithm and degree evaluation properties of the surfaces for these generalization over the rectangular domain are investigated. Furthermore, some fundamental properties for (p; q)-Bernstein Bezier curves are discussed.We get q-Bezier curves and surfaces for (u; v) in [0; 1] x [0; 1] when we set the parameter p1 = p2 = 1: In comparison to q-Bezier curves based on q-Bernstein polynomials, this generalization gives us more flexibility in controlling the shapes of curves
Some results on Lupaş (p; q)-Bernstein operators and its limit form
Get PDFIn this paper, statistical approximation properties of Lupaş (p; q)-analogue of Bernstein operators are studied. Rate of statistical convergence by means of modulus of continuity and Lipschitz type maximal functions has been investigated. Further Limit Lupaş (p; q)-Bernstein operators are defined and some results are investigated
η-Ricci Soliton on 3-Dimensional f-Kenmotsu Manifolds
Get PDFThe object of the present paper is to carry out η-Ricci soliton on 3-dimensional regularf-Kenmotsu manifold and we turn up some geometrical results. Furthermore we bring out the curvature conditions for which η-Ricci soliton on such manifolds are shrinking, steady or expanding. We wind up by considering examples of existence of shrinking and expanding η-Ricci soliton on 3-dimensional regularf-Kenmotsu manifolds
Complexes of lutein with bovine and caprine caseins and their impact on lutein chemical stability in emulsion systems: Effect of arabinogalactan
No full textLutein is an important xanthophyll carotenoid with many benefits to human health. Factors affecting the application of lutein as a functional ingredient in low-fat dairy-like beverages (pH 6.0–7.0) are not well understood. The interactions of bovine and caprine caseins with hydrophobic lutein were studied using UV/visible spectroscopy as well as fluorescence. Our studies confirmed that the aqueous solubility of lutein is improved after binding with bovine and caprine caseins. The rates of lutein solubilization by the binding to bovine and caprine caseins were as follows: caprine αS1-II-casein 34%, caprine αS1-I-casein 10%, and bovine casein 7% at 100 μM lutein. Fluorescence of the protein was quenched on binding supporting complex formation. The fluorescence experiments showed that the binding involves tryptophan residues and some nonspecific interactions. Scatchard plots of lutein binding to the caseins demonstrated competitive binding between the caseins and their sites of interaction with lutein. Competition experiments suggest that caprine αS1-II casein will bind a larger number of lutein molecules with higher affinity than other caseins. The chemical stability of lutein was largely dependent on casein type and significant increases occurred in the chemical stability of lutein with the following pattern: caprine αS1-II-casein \u3e caprine αS1-I-casein \u3e bovine casein. Addition of arabinogalactan to lutein-enriched emulsions increases the chemical stability of lutein-casein complexes during storage under accelerated photo-oxidation conditions at 25°C. Therefore, caprine αS1-II-casein alone and in combination with arabinogalactan can have important applications in the beverage industry as carrier of this xanthophyll carotenoid (lutein)
Almost output regulation of LFT systems via gain-scheduling control
No full textOutput regulation of general uncertain systems is a meaningful yet challenging problem. In spite of the rich literature in the field, the problem has not yet been addressed adequately due to the lack of an effective design mechanism. In this paper, we propose a new design framework for almost output regulation of uncertain systems described in the general form of linear fractional transformation (LFT) with time-varying parametric uncertainties and unknown external perturbations. A novel semi-LFT gain-scheduling output regulator structure is proposed, such that the associated control synthesis conditions guaranteeing both output regulation and L2 disturbance attenuation performance are formulated as a set of linear matrix inequalities (LMIs) plus parameter-dependent linear matrix equations, which can be solved separately. A numerical example has been used to demonstrate the effectiveness of the proposed approach