Journal Articles

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A finite difference study of radiative mixed convection MHD heat propagating Casson fluid past an accelerating porous plate including viscous dissipation and Joule heating effects
(Elsevier, 2024-04) Reddy, B. Prabhakar; Matao, P.M.; Sunzu, J.M.
A finite difference numerical simulation scrutiny is executed to evaluate the combined impacts of heat generation, buoyancy forces, viscous dissipation and Joule heating in unsteady hydromagnetic mixed convective chemically reactive and radiative Casson fluid flowing along an exponentially accelerating permeable vertical plate engrossed in a porous media by considering ramp surface concentration and temperature. The dimensionless non-linear coupled PDEs describing the flow model are dealt numerically by adopting the competent implicit Crank-Nicolson finite difference procedure. The variance of velocity, temperature, and concentration distributions are exposed via graphical representations due to the dissimilarity of the flow restrained parameters. Computational outcomes of the skin-friction, Nusselt and the Sherwood numbers are portrayed in the tabular pattern. The final outcomes of the research exposed that the impacts of thermal radiation, viscous dissipation, and heat production parameters enlarges the temperature and velocity distributions. The fluid motion deflates for growing Casson parameter and magnetic field intensity. The rising chemical reaction parameter suppresses the concentration and velocity distributions. Very importantly it is distinguished that fluid momentum, temperature, and concentration are quicker in the instance of isothermal plate temperature than ramp wall temperature. This kind of research may find specific industrial and medical utilizations such as glass manufacturing, crude oil purification, lubrication, paper production, blood transport study in cardiovascular design, etc.
Analysis and investigation of logical flaw of Zeno’s Achilles-Tortoise paradox
(Informa UK Limited, 2024-03-16) Mayila, Shega; Mpimbo, Marco; Rugeihyamu, Sylvester; Hari M. Srivastava
In this paper, we analyze the Achilles-Tortoise paradox, which denies the overtaking of the slowest runner (Tortoise) by the quickest runner (Achilles) because the pursuer must first reach the point whence the pursued started, so the slower must always hold the lead. The paradox translates into a requirement for the quicker to complete one by one an infinite sequence of distinct runs in a finite time to overtake the slower. This feat is impossible because the infinite sequence of distances contains no final distance to run, and the time to complete such a feat is not enough. However, we know better that in a race, the quickest always overtakes the slowest. Then why does the argument say otherwise? There should be logical flaws in its argumentation. Therefore, after an analysis of the paradox, we investigate the existence of such a flaw that exists in the argument itself or in the inferences its premises make. In addition to this, we present the new mathematical solution based on open balls in real Euclidean space, which shows that only a finite number of runs are needed by the quickest to overtake the slowest.
Analysis of effects of agriculture intervention using propensity score matching
(Macrothink Institute, 2015) Josephat, Peter; Likangaga, Rose
Nowadays the agriculture extension programme s are practiced in many parts of the world. There is a mixture of results about the effects of agriculture intervention programmes. The literature shows that the interventions are ineffective and have limited diffusion. On the other side, it shows that interventions are effective. Following different arguments about the effects of agriculture extension, this paper adopted Propensity Score Matching (PSM) to analyze the effects of District Agricultural Sector Investment Project (DASIP) using agriculture data. The study was conducted in rural Tanzania areas. It covered five regions namely Kagera, Mwanza, Mara, Simiyu and Kigoma. The study focused on agro ecological zone where corn is cultivated. Two methods which are questionnaire administration and direct oral interview were used to collect primary data. The collection of data using the questionnaire was done from both participants (359) and non participants (519). Before running the independent t test, the estimation of propensity score was done using Logistic regression. Thirteen confounding variables were used to estimate propensity scores.The effects of the intervention were analysed by considering four items namely the earnings from corn production, value of livestock owned value of household assets owned, and value of farm assets owned. The results show that none of the four factors had significant result as the p values are greater than 0.05. This implies that the earning between farmers participating in DASIP are not significant different from those who do not participate in the programme. The study recommends that the group activities should last longer rather than changing them from time to time.
Application of Odd Lomax log-logistic distribution to cancer data
(Elsevier, 2024-03) Kailembo, Benson Benedicto; Gadde, Rao Srinivasa; Kirigiti, Peter Josephat
The effectiveness of the parental distribution is modified in this article by adding flexibility, allowing it to capture all characteristics of the provided real-world data sets. This is accomplished by using the T-X class of distributions to generalize the parental distribution. Odd Lomax loglogistic distribution or OLLLD in short, is the name of the generalized parental distribution. The fundamental statistical properties of OLLLD are explicitly expressed. The maximum likelihood estimation approach is used to estimate the unidentified OLLLD parameters. In order to investigate the fit of the approach employed in estimating the parameters of OLLLD, the data are generated and an investigation done. Again, the ability of OLLLD is evaluated by fitting it to the real survival time data set of breast cancer.
Asymptotic behavior of solutions of matrix lyapunov integro differential equations
(Korean Journal Publishing Service, 2014) Sarma, Goteti V.; Hugo, Alfred
The asymptotic behavior of solutions of Lyapunov type matrix Volterra integro differential equation, in which the coefficient matrices are not stable, is studied by the method of reduction.
Charged anisotropic composite stellar object with strange, polytropic and gaseous matter
(Elsevier, 2024-08) Olengeile, Lilian; Sunzu, Jefta M.; Mkenyeleye, Jason M.
In this study, we build a charged star model with three layers with distinct equations of state. The core, intermediate layer, and envelope layer obey linear, polytropic, and Chaplygin equations of state, respectively. The model satisfies the physical requirements for the matter variables, gravitational potentials, and stability conditions. We have generated within-acceptable range masses and radii for stars. We also recover the masses and radii for the stars PSRJ1903+0327, PSRJ1614-2230, SAXJ1808.4-3658, Vela X-1, and EXO1785-248 from earlier investigations which shows astrophysical significance of our model.
Charged anisotropic models for quark stars
(Springer, 2014) Sunzu, J. M.; Maharaj, S. D.; Ray, S.
We perform a detailed physical analysis for a class of exact solutions for the Einstein-Maxwell equations. The linear equation of state consistent with quark stars has been incorporated in the model. The physical analysis of the exact solutions is performed by considering the charged anisotropic stars for the particular nonsingular exact model obtained by Maharaj, Sunzu and Ray. In performing such an analysis we regain masses obtained by previous researchers for isotropic and anisotropic matter. It is also indicated that other masses and radii may be generated which are in acceptable ranges consistent with observed values of stellar objects. A study of the mass-radius relation indicates the effect of the electromagnetic field and anisotropy on the mass of the relativistic star
Charged anisotropic models via embedding
(Springer, 2021) Mathias, Alberto K.; Maharaj, Sunil D.; Sunzu, Jefta M.; Mkenyeleye, Jason M.
We generate exact solutions to the Einstein–Maxwell field equations by analysing the embedding condition. We obtain a relationship between gravitational potentials that helps to solve the embedding condition and integrate the field equations. Our choice of the measure of anisotropy and electric field are physically realistic. Our model contains several previously known solutions as special cases. These include the investigations of interior Schwarzchild metric, Finch and Skea, Hansraj and Maharaj, Feroze and Siddiqui, and Manjonjo, Maharaj and Moopanar. We also describe the structure and properties of the relativistic star by including graphical representations. Our analysis shows that the body is stable, all energy conditions are satisfied, the regularity condition is not violated, forces under equilibrium condition are balanced, all matter variables are well behaved and the matching conditions are satisfied at the boundary of the relativistic star.
Competency and performance gap between executive and non-executive employees of banks in Kerala, India
(WJRR Journal, 2021) Balan, Ramkumar T.
This paper assesses the Competency and Performance of bank employees of Four banks in Kerala, India. The gap in the performance and competency of executive and non- executive employees of the banks were determined. The linear regression model is estimated on dimensions of this efficiency measures. Also logistic regression models on competency and performance for executive and non-executive employees were identified. The dimensions of effectiveness of employees in a banking work place on both groups were compared. The gap in the characteristics of two sets of employees is illustrated for various demographic groups.
Control charts for monitoring process capability index using median absolute deviation for some popular distributions
(Multidisciplinary Digital Publishing Institute, 2019) Aslam, Muhammad; Rao, G. Srinivasa; AL-Marshadi, Ali Hussein; Ahmad, Liaquat; Jun, Chi-Hyuck
A control chart monitoring the process capability index (PCI) using median absolute deviation (MAD) is proposed to analyze the industrial process performance. Extensive simulation studies were carried out to evaluate the performance of MAD-based PCI control charts under the low, moderate, and high asymmetric conditions when the process characteristic follows Weibull, log-normal, and gamma distributions. The performance of the proposed control charts was evaluated based on the average run lengths. The practical implementation of the proposed charts was also illustrated with industrial data.
Designing of multiple dependent state repetitive sampling plan for type-II generalized half logistic distribution
(Springer Nature, 2021) Rao, Gadde Srinivasa; Jilani, S. D.; Rao, A. Vasudeva
In this article, we present a new multiple dependent state repetitive (MDSR) sampling plan for attributes based on consider Type-II generalized half logistic distribution (TGHLD) with known shape parameter is consider here. The optimal parameter of the proposed plan is used to determine the operating characteristic (OC) curve approach using two point’s method. The results are explained with tables. We have made the comparison of proposed design with the usual multiple dependent state (MDS) sampling plans, repetitive acceptance sampling plan (RASP) and single sampling plan (SSP) in Average Sample Number (ASN). The proposed plan is demonstrated with the help of real- life data.
Designing of multiple dependent state sampling plan for Type-II generalized half logistic distribution
(Informa UK Limited, 2024-03-22) Jilani, Sd.; Rao, Gadde Srinivasa; Rao, A. Vasudeva; Yilun Shang
In this study, we propose the multiple dependent state (MDS) sampling plan for a time truncated life test when the lifetime of product follows the Type-II Generalized Half Logistic Distribution (TGHLD). The quality of the product is considered in terms of percentile lifetime. The optimal plan parameters of the our proposed MDS sampling plan, such as the sample size, the acceptance and rejection numbers, and the number of preceding lots needed for making the decision whether to accept or reject the current lot, are determined using the approach of two points on the operating characteristic curve. Tables are obtained for various values of shape parameter and results are discussed. The real data analysis is given to illustrate the applicability of the proposed in the industry. Comparison is also made with the existing plans.
Double-layered anisotropic stellar model of embedding class I with gaseous envelope
(Elsevier, 2023) Mathias, Amos Vincent; Mkenyeleye, Jason Maombi; Sunzu, Jefta M.
The current paper presents a double-layered neutral anisotropic stellar model in general relativistic setting. The model is developed by using Einstein field equations and class I embedding condition. We consider the core with quark matter obeying linear equation of state and envelope layer with gaseous matter admitting Chaplygin gas equation of state. The interior and exterior metric coefficients match smoothly at the interface of core and envelope layers and at the stellar surface. The profiles for matter variables, stability and energy conditions show acceptable trend for physical stellar models. In this model, stellar masses and radii consistent with compact stars HerX-1, 4U1538-52, SAXJ1808.4-3658, CenX-3 and SMCX-1 are generated. We note that studies of multi-layered stars with gaseous envelope and embedding class I condition are missing in investigations conducted in the past.
An economic reliability test plan for exponentiated half logistic distributed lifetimes
(International Journal of Statistics and Applied Mathematics, 2020) Naidu, Ramesh CH; Rao, Srinivasa G.; Rosaiah, K.
The exponentiated half logistic distribution introduced by Cordeiro et al. (2014) is a probability model for the life time of an item. A submitted lot will be accepted or rejected based on the sampling plans where items are to be tested and for collecting the life of items, these plans are called reliability test plans. The present reliability test plan is more desirable than similar plans exists in literature is entrenched with respect to termination time of the experiment. For a range of stated acceptance number we determine the minimum life test termination time, sample size, and producer’s risk.
An economic reliability test plans for odd generalized exponential log–logistic distribution
(Indian Association for Reliability and Statistics (IARS), 2020) Rosaiah, K.; Rao, Srinivasa G.; Sivakumar, D.C.U.; Kalyani, K.
Odd generalized exponential log-logistic distribution introduced and studied quite extensively by Rosaiah et al. (2016) is considered as a probability model for the lifetime of products. In this article, the sampling plans are developed for percentile lifetimes using two approaches. In approach–I, minimum sample size necessary to ensure a specified percentile lifetime is determined based on the termination time and acceptance number along with operating characteristic values and producer’s risk. In approach-II, by fixing the number of failures, we determine the life test termination time along with operating characteristic values. The sampling plans constructed using two approaches are compared with respect to life test termination time.
Effects of chemical reaction on MHD flow past an impulsively started Infinite vertical plate with variable temperature and mass diffusion in the presence of Hall Current
(The Serbian Society for Computational Mechanics (SSCM), 2019) Reddy, Prabhakar B.; Peter, J.
In this paper, the effects of chemical reaction on unsteady MHD flow of viscous incompressible electrically conducting fluid past an impulsively started oscillating vertical plate with variable temperature and constant mass diffusion in the presence of Hall current have been presented. The dimensionless governing partial differential equations of the flow have been solved numerically by using the Crank-Nicolson implicit finite difference scheme. The numerical solutions for primary fluid velocity, secondary fluid velocity, fluid temperature and fluid concentration are plotted graphically whereas the numerical results of primary skin friction, secondary skin frictions, rate of heat and mass transfer are presented in tabular form for various parameters involved. A comparison has been provided between the present results and with the existing analytical solutions by the Laplace transforms technique. It has been found that the results of the present study are in excellent agreement with previously obtained results.
Effects of chemical reaction on transient MHD flow with mass transfer past an impulsively fixed infinite vertical plate in the presence of thermal radiation
(Sciendo, 2019) Reddy, Prabhakar B.
The effects of chemical reaction on a transient MHD mixed convection flow with mass transfer past an impulsively fixed infinite vertical plate under the influence of a transverse magnetic field have been presented. The medium is considered to be non-scattering and the fluid to be non-gray having emitting-absorbing and optically thick radiation limit properties. The dimensionless governing equations of the flow and mass transfer with boundary conditions are solved numerically by using the Ritz finite element method. The numerical results for the velocity, temperature and the concentration profiles as well as the skin-friction coefficient for different values of physical parameters such as the radiation parameter, magnetic parameter, Schmidt number and chemical reaction parameter have been obtained and presented through graphs and tables. It has been found that there is a fall in the temperature and velocity for both air and water as the radiation parameter is increased. An increase in the Schmidt number and chemical reaction parameter results a decrease in the concentration and velocity profiles for both air and water. Furthermore, an increase in the radiation parameter, magnetic parameter, Schmidt number and chemical reaction parameter decreases the skin-friction.
Effects of thermal radiation on MHD chemically reactive flow past an oscillating vertical porous plate with variable surface conditions and viscous dissipation
(i-manager Publications, 2019) Reddy, Prabhakar B.; Muthucumaraswamy, R.
The purpose of this article is to investigate the thermal radiation effects on unsteady hydro-magnetic viscous dissipative fluid flow of an incompressible and electrically-conducting past an oscillating vertical plate in a porous medium with variable surface conditions in the presence of chemical-reaction. The Ritz FEM has been applied to solve the governing equations of the flow. The numerical solutions for the fluid velocity, fluid temperature, and fluid concentration were presented graphically. Numerical results of the skin-friction are presented in tables. It has been found that the fluid temperature decreased in the boundary-layer as the radiation parameter increased whereas it is increased when Eckert number increased. Increase in the Schmidt number and chemical reaction tends to decrease the concentration of fluid. The permeability parameter, Eckert number, and the time tends to accelerate the fluid velocity whereas magnetic field, radiation and chemical reaction tends to decelerate the fluid velocity in case of cooled plate and opposite effect is observed in case of heated plate. These results are in very good agreement with earlier reported studies.
Estimation of reliability in a multicomponent stress–strength system for the exponentiated moment-based exponential distribution
(Multidisciplinary Digital Publishing Institute, 2019) Rao, Srinivasa G.; Bhatti, Fiaz Ahmad; Aslam, Muhammad; Albassam, Mohammed
A multicomponent system of k components with independent and identically distributed random strengths X 1, X 2 , … X k , with each component undergoing random stress, is in working condition if and only if at least s out of k strengths exceed the subjected stress. Reliability is measured while strength and stress are obtained through a process following an exponentiated moment-based exponential distribution with different shape parameters. Reliability is gauged from the samples using maximum likelihood (ML) on the computed distributions of strength and stress. Asymptotic estimates of reliability are compared using Monte Carlo simulation. Application to forest data and to breaking strengths of jute fiber shows the usefulness of the model.
Estimation of stress–strength reliability from exponentiated inverse rayleigh distribution
(World Scientific Publishing Company, 2019) Rao, G. S.; Mbwambo, S.; Josephat, P. K.
This paper considers the estimation of stress–strength reliability when two independent exponential inverse Rayleigh distributions with different shape parameters and common scale parameter. The maximum likelihood estimator (MLE) of the reliability, its asymptotic distribution and asymptotic confidence intervals are constructed. Comparisons of the performance of the estimators are carried out using Monte Carlo simulations, the mean squared error (MSE), bias, average length and coverage probabilities. Finally, a demonstration is delivered on how the proposed reliability model may be applied in data analysis of the strength data for single carbon fibers test data.

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