Discriminating Between Generalized Exponential Distribution and Some Life Test Models Based on Population Quantiles

A test statistic based on population quantiles using sample order statistics is suggested. The quantiles of the test statistics are evaluated for generalized exponential distribution. Similar test statistic based on moments of sample order statistic is referred and the proposed test formula is compared with it. Between the pairs of the above models it is established that the test formula proposed by us is more effective and useful than the formula based on the moments of order statistics as developed by Sultan (2007)

Limited Failure Censored Life Test Sampling Plan in Burr Type X Distribution

The Burr type X distribution is considered as a life time random variable of a product whose lots are to be decided for acceptance or otherwise on the basis of sample lifetimes drawn from the lot. The sample is divided into various groups in order to develop a group sampling plan in such a way that the life testing experiment is terminated as soon as the first failure in each group is observed. The acceptance criterion based on the theory of order statistics is proposed and is shown to be more economical than a criterion proposed in the earlier similar works

Some Methods of Estimation from Censored Samples in Exponential and Gamma Models

Two popular life testing models exponential and one where its generalization is gamma are considered. Estimation of scale parameter from a general Type-II doubly censored sample is attempted by the principle of maximum likelihood method. Resulting equations found to be giving iterative solutions. As an alternative to iterative solution certain admissible modifications to the estimating equations are suggested in special cases. The resulting estimates are compared with the exact maximum likelihood estimates analytically or through simulation. The results are also extended for reliability estimation

Estimation and Testing in Type I Generalized Half Logistic Distribution

A generalization of the half logistic distribution is developed through exponentiation of its cumulative distribution function and termed the Type I Generalized Half Logistic Distribution (GHLD). GHLD’s distributional characteristics and parameter estimation using maximum likelihood and modified maximum likelihood methods are presented with comparisons. Comparison of Type I GHLD and the exponential distribution is conducted via likelihood ratio criterion

Aloe Vera – Nature’s Power

Aloe vera is a plant used in various fields like Homeopathy, Ayurveda, Allopathy, Siddha, Unani, cosmetology, dermatology and surprisingly even in dentistry. Aloe vera is richest source of health for humans with various benefits and properties like wound healing, anti-microbial, anti-inflammatory, immunomodulatory, anti-septic, anti-helmenthic and anti-oxidant. Aloe vera is used in dentistry as active ingredient in tooth pastes, tooth gels and mouth rinse for plaque control, treatment of various oral lesions, halitosis and gingivitis, as decontaminant in endodontics, in extraction sockets, dental implants and in denture care. This paper gives an overview of aloe vera plant, its ingredients, properties and various therapeutic and dental applications

Ring opening of oxiranes catalyzed by Mn-Salen immobilized mesoporous materials

Mn-Salen immobilized mesoporous materials were found to be efficient solid catalysts for the nucleophilic ring opening of oxiranes with TMSN3, TMSCN and aniline

Friedel-Crafts sulfonylation of aromatics catalysed by solid acids: an eco-friendly route for sulfone synthesis

A mild and efficient catalytic method for Friedel-Crafts sulfonylation of arenes to the corresponding sulfones using a catalytic amount of reusable solid acid and arene- or alkanesulfonyl chlorides, sulfonic anhydrides and sulfonic acids as sulfonylating agents is described. Solid acids enable formation of a sulfone by the reaction of a sulfonic acid and an arene for the first time. In pursuit of the development of the best catalytic system, various metal-exchanged K10 montmorillonites and synthetic zeolites such as zeolite beta, zeolite Y and ZSM-5 have been screened for Friedel-Crafts sulfone synthesis. Fe3+-montmorillonite in the family of clays and zeolite beta in the family of zeolites exhibit higher activity. The activity is correlated to the presence of the right mix of Bronsted and Lewis acidic sites. The regioselective sulfonylation of toluene and naphthalene are studied in which para and beta selectivities are observed respectively

Polymer-anchored palladium catalyst in carbonylation of organic halides - the first example of triphase catalysis

Polymer-anchored palladium-catalysed carbonylation of organic halides affords oxo esters in reasonable- yields under solid-liquid-solid phase transfer conditions at mild pressure and short durations

Acceptance sampling plans for percentiles based on the inverse Rayleigh distribution

In this article, acceptance sampling plans are developed for the inverse Rayleigh distribution percentiles when the life test is truncated at a pre-specified time. The minimum sample size necessary to ensure the specified life percentile is obtained under a given customer’s risk. The operating characteristic values (and curves) of the sampling plans as well as the producer’s risk are presented. Two examples with real data sets are also given as illustration