Browsing Mathematics, Statistics & Physics by Title
Now showing items 534-553 of 689
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Polycircular domains, numerical conformal mappings, and moduli of quadrilaterals
( Springer Nature , 2022 , Article)We study numerical conformal mappings of planar Jordan domains with boundaries consisting of finitely many circular arcs, also called polycircular domains, and compute the moduli of quadrilaterals for these domains. ... -
Population immunity of natural infection, primary-series vaccination, and booster vaccination in Qatar during the COVID-19 pandemic: an observational study
( Elsevier , 2023 , Article)BackgroundWaning of natural infection protection and vaccine protection highlight the need to evaluate changes in population immunity over time. Population immunity of previous SARS-CoV-2 infection or of COVID-19 vaccination ... -
Portfolio Selection Problem Using CVaR Risk Measures Equipped with DEA, PSO, and ICA Algorithms
( MDPI , 2022 , Article)Investors always pay attention to the two factors of return and risk in portfolio optimization. There are different metrics for the calculation of the risk factor, among which the most important one is the Conditional ... -
Positron annihilation and ion beam analysis of ion-bombardment-induced hydrogen release and oxidation of ultra high molecular weight polyethylene
( Elsevier , 2007 , Article)Ultra high molecular weight polyethylene was bombarded with He+ and Ar+ ions to fluences ranging from 1013 to 2×1016 ions/cm2. Rutherford backscattering and nuclear reaction analysis were applied to study mechanism of ... -
Positron annihilation lifetime study of helium ions implanted polyethylene blends
( Trans Tech Publications Ltd , 2004 , Conference Paper)The structural defects of linear low density polyethylene (LLDPE) and high density polyethylene (HOPE) blends implanted with helium ions were investigated using position annihilation lifetime (PAL) technique. The positron ... -
Positron annihilation lifetime study of pure and treated polyvinyl chloride
( scientific.net , 1997 , Article)Positron annihilation lifetime technique (PAL) has been applied to investigate the behavior of the free volume in pure and doped polyvinyl chloride (PVC) as a function of Pb concentration and temperature. It is noticed ... -
Positron annihilation studies of the effect of gamma irradiation dose in polymers
( Elsevier Ltd , 2003 , Conference Paper)Positron annihilation lifetime (PAL) technique has been applied to study the effect of gamma irradiation dose on the structure of low-density polyethylene and polystyrene. The positron annihilation lifetime measurements ... -
Positron annihilation study on polyaniline nanocomposite used for Pb(II) ion removal
( Taylor & Francis , 2016 , Article)Nanocomposites of polyaniline (PANI) with three different concentrations of micrometre-sized sawdust are prepared in aqueous media via chemical casting method at room temperature. Thereafter, the removal efficiency of the ... -
PPF-dependent fixed point results for multi-valued ? F-contractions in Banach Spaces and Applications
( MDPI AG , 2019 , Article)The solutions for many real life problems is obtained by interpreting the given problem mathematically in the form of f (x) = x. One of such examples is that of the famous Borsuk-Ulam theorem, in which using some fixed ... -
Practitioners guide on parametric, nonparametric, and semiparametric profile monitoring
( Wiley , 2021 , Article Review)Profile monitoring is one of the methods used in statistical process control ((Formula presented.)) to understand the functional relationship between response and explanatory variables by tracking this relationship and ... -
Prediction of future failures in the log-logistic distribution based on hybrid censored data
( Springer , 2022 , Article)We consider the prediction of future observations from the log-logistic distribution. The data is assumed hybrid right censored with possible left censoring. Different point predictors were derived. Specifically, we obtained ... -
Preliminary test estimation in the two parameter exponential distribution based on record values
( Nova Science Publishers , 2010 , Article)We considered estimation of the parameters of the exponential distribution based on record data in the presence of prior information. Preliminary test and shrinkage estimators are developed and their properties are ... -
Preliminary Test Estimation of the Threshold in the Two-Parameter Exponential Distribution Based on Records and Minimax Regret Significance Levels
( Taylor and Francis Ltd. , 2017 , Article)SYNOPTIC ABSRACT: We consider preliminary test estimation of the threshold parameter of the two-parameter exponential distribution using record-breaking data. We use the minimax regret criterion on the risk function of the ... -
Preliminay test estimation in the two parameter exponential distribution based on record values
(2010 , Article)We considered estimation of the parameters of the exponential distribution based on record data in the presence of prior information. Preliminary test and shrinkage estimators are developed and their properties are ... -
Preparation, spectroscopic and structural studies on charge-transfer complexes of 2,9-dimethyl-1,10-phenanthroline with some electron acceptors
( Elsevier , 2007 , Article)Charge-transfer (CT) complexes formed in the reactions of 2,9-dimethyl-1,10-phenanthroline (Me2phen) with some acceptors such as chloranil (Chl), picric acid (HPA) and chloranilic acid (H2CA) have been studied in the defined ... -
Prevalence and correlates of autism spectrum disorder in Qatar: a national study
( Blackwell Publishing Ltd , 2019 , Article)Background Few epidemiological data on autism spectrum disorders (ASD) exist for Arabic countries. We conducted the first survey of ASD in Qatar, a population with high consanguinity level. Methods This cross‐sectional ... -
Prevalence of hepatitis B and C viruses among migrant workers in Qatar.
( Springer Nature , 2024 , Article)Limited data exist on viral hepatitis among migrant populations. This study investigated the prevalence of current hepatitis B virus (HBV) infection and lifetime hepatitis C virus (HCV) infection among Qatar's migrant craft ... -
Production of flexible nanocomposite membranes for x-ray detectors
( Elsevier , 2020 , Article)Flexible membranes of poly(vinyl alcohol) (PVA) polymer and CuO nanoparticles for x-ray detection applications are reported in this work. PVA represents a polymer matrix for nanoparticles, and its flexibility and electrical ... -
Production of hazardous gas sensors using spinel ferrite nanoparticles
( Hamad bin Khalifa University Press (HBKU Press) , 2018 , Conference Paper)This work reports on sensitive and selective gas sensors based on copper ferrite (CuFe2O4) nanoparticles. The nanoparticles were produced different methods including: colloid microwave assisted hydrothermal method, and ... -
Production of hazardous gas sensors using spinel ferrite nanoparticles
( Hamad bin Khalifa University Press (HBKU Press) , 2018 , Conference Paper)This work reports on sensitive and selective gas sensors based on copper ferrite (CuFe2O4) nanoparticles. The nanoparticles were produced different methods including: colloid microwave assisted hydrothermal method, and ...