Browsing Mathematics, Statistics & Physics by Title
Now showing items 564-583 of 715
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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 ... -
Production of metal-oxide nanoclusters using inert-gas condensation technique
( Elsevier B.V. , 2017 , Article)Inert-gas condensation is a novel technique that can be used to produce nanoclusters for different applications. In the present work, dc sputtering combined with inert-gas condensation were used to produce copper oxide ... -
Production of sensitive gas sensors using CuO/SnO2 nanoparticles
( Springer Verlag , 2019 , Article)Metal oxide nanoparticles, such as CuO and SnO2, are outstanding systems for H2S gas sensing in air. In this work, those nanoparticles were deposited with different mixing percentages on substrates to form percolating ... -
Production Of Size-selected Copper Nanoclusters For Petroleum Refinery Applications
( Hamad bin Khalifa University Press (HBKU Press) , 2014 , Conference Paper)Atomic nanoclusters exhibit large surface to volume ratio which enhances their ability to interact with external materials, thus, they can be utilized efficiently for catalysts and gas sensing applications. Copper (Cu) ... -
Proposing a Nondestructive and Intelligent System for Simultaneous Determining Flow Regime and Void Fraction Percentage of Gas-Liquid Two Phase Flows Using Polychromatic X-Ray Transmission Spectra
( Springer , 2021 , Article)Two phase flows are of particular importance in various research fields. In the current article, a novel system consists of an X-ray tube and one sodium iodide crystal detector with ability of determining type of flow ... -
Protection from previous natural infection compared with mRNA vaccination against SARS-CoV-2 infection and severe COVID-19 in Qatar: a retrospective cohort study
( Elsevier , 2022 , Article)BackgroundUnderstanding protection conferred by natural SARS-CoV-2 infection versus COVID-19 vaccination is important for informing vaccine mandate decisions. We compared protection conferred by natural infection versus ... -
Protection of Omicron sub-lineage infection against reinfection with another Omicron sub-lineage
( Nature Research , 2022 , Article)There is significant genetic distance between SARS-CoV-2 Omicron (B.1.1.529) variant BA.1 and BA.2 sub-lineages. This study investigates immune protection of infection with one sub-lineage against reinfection with the other ...