Efficient Stand-Alone Generalized Inverse Algorithms and Software for Engineering/Sciences Applications: Research and Education

Efficient numerical procedures for finding the generalized (or pseudo) inverse of a general (square/rectangle, symmetrical/unsymmetrical, non-singular/singular, real/complex numbers) matrix and solving systems of Simultaneous Linear Equations (SLE) are formulated and explained. The developed procedures and its associated computer software (under MATLAB computer environment) have been based on special Cholesky factorization schemes (for a singular matrix), the generalized inverse of the matrix product, and were further enhanced by the Domain Decomposition (DD) formulation. Test matrices from different fields of applications have been chosen, tested and compared with other existing algorithms. The results of the numerical tests have indicated that the developed procedures are far more efficient than existing algorithms. Furthermore, an educational version of the generalized inverse algorithms and software for solving SLE has also been developed to run any FORTRAN and/or \u27C\u27 programs over the web. This developed technology and software is freely available and can run on any device with internet connectivity and browser capability

System Reliability Estimation of Divert Attitude Control System of a Launch Vehicle using Bayesian Networks

Divert attitude and control system (DACS) is a one-shot system and provides attitude correction and translation of the Launch vehicle. DACS consists of many flight critical sub systems which are arranged in a series configuration. The traditional Reliability block diagram and Fault tree diagram methods are unsuitable for reliability modelling, when considering uncertainty among the components and system. Bayesian network is the natural choice to model dependencies among the components and system. DACS being one shot system, it is very expensive and time consuming to test more number of systems during the design and development. Hence the data is drawn from component level, subsystem level and expert opinion is used for reliability estimation. In this paper, Bayesian network modelling of DAC system was carried out for estimating the reliability using multi-level data. An algorithm is developed for computation of Conditional probabilities in Bayesian network. Posterior probability distribution of components is calculated using Markov Chain Monte Carlo (MCMC) simulations and results are compared with Junction tree based exact inference algorithm. MATLAB code is developed to estimate the reliability of DAC system

Influence of Resin Viscosity on Physical Properties of a Composite Shell Wound on a Low Density Material Mandrel

This study is made to improve the structural performance of composite shells/ vessels meant for aerospace vehicles. The effect of resin viscosity on the physical properties of carbon/ epoxy composite shell wound on polyurethane (PU) foam-based mandrel is studied and presented in this paper. Cylindrical shells were manufactured through the filament winding process at different resin viscosities. The physical properties of the composite shell are found to be improved significantly with a reduction in resin viscosity. Resin pick-up in impregnated fibers is found to be lower by 4.5 %, whereas mass and thickness of the shells are recorded to be lower by 3 % and 5.4 % respectively at resin viscosity range of 600 -760 mPa.s compared to the viscosity range of 1380 – 2080 mPa.s. Fiber volume fraction and density of composite shell are found to be higher by 6.3 % and 2.8 % at the same resin viscosity range. This trend reverses/stabilizes after further heating and corresponding lowered resin viscosity. Experiment and their result indicate an optimal viscosity range of 600 – 760 mPa.s. for filament winding of efficient carbon/ epoxy composite shel

INVESTIGATION OF KONDAGOGU GUM TO DEVELOP TRANSDERMAL FILM OF REPAGLINIDE

 Objective: In the present study, an attempt was made to develop polymeric blend transdermal patch of repaglinide using hydroxypropyl methyl cellulose (HPMC) K4M and kondagogu gum.Methods: A series of repaglinide drug-incorporated HPMC K4M-kondagogu gum matrix films were prepared by solvent casting method. The prepared transdermal films were evaluated for various parameters such as thickness, tensile strength, folding endurance, % elongation, % moisture content, % moisture uptake, % drug content, in vitro drug release, and drug excipient compatibility.Results: The Fourier-transform infrared spectra of the pure drug as well as drug-incorporated formulation indicated that no chemical interaction occurred between the drug and the polymers used. Differential scanning calorimetry thermograms of the pure drug and prepared formulation indicated that the drug has dispersed in micron level in the prepared films. In vitro release study data of prepared formulations were fitted into various mathematical models, and the best-fit model was found to be Higuchi model.Conclusion: Among all the formulations studied, the formulation F4 was found to be an optimized composition for efficient transdermal delivery of repaglinide for 24 h study period. Stability studies of the drug formulations concluded that the drug was stable in the optimized formulation for the study period

FORMULATION AND EVALUATION OF COLON TARGETED MATRIX TABLET USING NATURAL TREE GUMS

Objective: To develop a novel colon targeted tablet formulation using natural polysaccharides such as kondagogu gum and ghatti gum as carriers and diltiazem hydrochloride as a model drug.Methods: The polymer-drug tablets were prepared by wet granulation technique, coated with two layers viz., inulin as an inner coat followed by shellac as outer coat and evaluated for properties such as average weight, hardness and coat thickness. In vitro release studies of prepared tablets were carried out for 2 h in pH 1.2 HCl buffer, 3 h in pH 7.4 phosphate buffer and 6 h in simulated colonic fluid (SCF) in order to mimic the conditions from mouth to colon.Results: Percentage weight variation, percent friability and content of active ingredient for all the formulations were found to be well within United States Pharmacopoeia (USP) limits. Out of both the polymers, the tablets prepared with ghatti gum showed the maximum hardness of 7.1 kg/cm2. The FTIR spectra of pure diltiazem HCl and the formulation KF3 were found to be identical. From the DSC, it was evident that the melting point peak of diltiazem HCl and formulation KF3 were observed at 217.16 and 218.34 °C respectively. In vitro studies revealed that the tablets coated with shellac (2.5% w/w), prevented the drug release in stomach environment and inulin coated tablets (4% w/w) have limited the drug release in the small intestinal environment. The data obtained from in vitro drug release studies were fit into Peppas model and in all the cases the value of A was found to be more than 2, i.e., drug release by a combination of both diffusion and erosion-controlled drug release.Conclusion: The study revealed that polysaccharides as carriers and inulin and shellac as a coating material can be used effectively for colon targeting of drugs for treating local as well as systemic disorders

Adipocytokine Levels in Genetically High Risk for Type 2 Diabetes in the Indian Population: A Cross-Sectional Study

Introduction. In view of the noteworthy role of adipocytokines in the onset of insulin resistance and diabetes in gene-knockout-rat-model-cell-line studies we aimed to study the influence of genetic predisposition for diabetes on adipocytokine levels and their role in building insulin-resistance-like environment well before the onset of diabetes; thus a hypothesis can be drawn on their role in developing diabetes in high risk population. Methods. Ages between 18 and 22 years were selected and divided into three groups. Group I (n=81): control group with no family history of diabetes. Group II (n=157): with one of their parents with history of type 2 diabetes. Group III (n=47): with both parents having history of type 2 diabetes. In all the groups we estimated fasting plasma glucose, insulin and adipocytokines like adiponectin, leptin, TNF-α, and IL-6. Results. Of all adipocytokines we observed significantly lower levels of adiponectin (8.7±1 μg/mL in group III and 9.5±1.3 μg/mL group II) when compared to control (11.0±1.2 μg/mL; P<0.01) and it has strong correlation with family history of diabetes with Pearson’s coefficient of −0.502. Linear regression analysis showed significant negative association with HOMA-IR (P<0.01) and logistic regression analysis showed highest association with parental diabetes (P<0.01; OR .260, 95% CI .260–.468). Conclusion. Genetic predisposition for diabetes may influence adiponectin gene expression leading to decrease in its plasma concentration, which might play a key role in developing diabetes in near future