Mathematics, Statistics & Physics: Recent submissions

Now showing items 661-680 of 738

    • Antiferromagnetism in EuPdGe3 

      Albedah, M.A.; Al-Qadi, K.; Stadnik, Z.M.; Przewoznik, J. ( Elsevier Ltd , 2014 , Article)
      The results of X-ray diffraction, magnetic susceptibility and magnetization, and 151Eu Mössbauer spectroscopy measurements of polycrystalline EuPdGe3 are reported. EuPdGe3 crystallizes in the BaNiSn3-type tetragonal structure ...

    • A discussion on generalized almost contractions via rational expressions in partially ordered metric spaces 

      Mustafa, Zead; Karapinar, Erdal; Aydi, Hassen ( Springer International Publishing , 2014 , Article)
      The main purpose of this paper is to give some fixed point results for mappings involving generalized (Formula presented.)-contractions in partially ordered metric spaces. Our results generalize, extend, and unify several ...

    • Fate of accidental symmetries of the relativistic hydrogen atom in a spherical cavity 

      Al-Hashimi, M.H.; Shalaby, A.M.; Wiese, U.-J. ( Elsevier Masson , 2015 , Article)
      The non-relativistic hydrogen atom enjoys an accidental SO(4) symmetry, that enlarges the rotational SO(3) symmetry, by extending the angular momentum algebra with the Runge–Lenz vector. In the relativistic hydrogen atom ...

    • On computing joint invariants of vector fields 

      Azad, H.; Biswas, I.; Ghanam, R.; Mustafa, M.T. ( Elsevier , 2015 , Article)
      A constructive version of the Frobenius integrability theorem-that can be programmed effectively-is given. This is used in computing invariants of groups of low ranks and recover examples from a recent paper of Boyko etal. (2009).

    • K-shell photoionization of O+ and O2+ ions: Experiment and theory 

      Bizau, J.M.; Cubaynes, D.; Guilbaud, S.; Al-Shorman, M. M.; Gharaibeh, M. F.; ... more authors ( American Physical Society , 2015 , Article)
      Absolute cross sections for the single and double K-shell photoionization of carbon like O2+ and nitrogen like O+ ions were measured in the 526–620-eV photon energy range by employing the ion-photon merged-beam technique ...

    • On fixed points of Berinde's contractive mappings in cone metric spaces 

      Abbas, Mujahid; Vetro, Pasquale; Khan, Safeer Hussain ( North University of Baia Mare , 2010 , Article)
      In this paper we establish some common fixed point theorems for two self-mappings satisfying a generalized contractive condition. This result generalizes well known comparable results in the literature. As an application, ...

    • Error analysis associated with uniform Hermite interpolations of bandlimited functions 

      Annaby, M.H.; Asharabi, R.M. ( Korean Mathematical Society , 2010 , Article)
      We derive estimates for the truncation, amplitude and jitter type errors associated with Hermite-type interpolations at equidistant nodes of functions in Paley-Wiener spaces. We give pointwise and uniform estimates. Some ...

    • Two-phase sample size estimation with pre-assignedvariance under normality assumption 

      Salehi, M.; Levy, P.S.; Rao, J. ( Shiraz University , 2010 , Article)
      We develop a two phase sampling procedure to determine the sample size necessary to estimate the population mean of a normally distributed random variable and show that the resulting estimator has preassigned variance and ...

    • Preliminary test estimation in the two parameter exponential distribution based on record values 

      Baklizi, A. ( 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 ...

    • Weak and strong convergence theorems without some widely used conditions 

      Khan, S.H.; Fukhar-Ud-Din, H. ( Academic Publications, Ltd. , 2010 , Article)
      We establish weak (strong) convergence of Ishikawa iterates of two asymptotically (quasi-)nonexpansive maps without any condition on the rate of convergence associated with the two maps. Moreover, our weak convergence ...

    • On the preparation of electron sensor using LiRbSO4 samples 

      El-Muraikhi, M.; Kassem, M. E.; Gaafar, M.; Abdel Gawad, M. M. H.; Ragab, I. M. ( WILEY-VCH Verlag GmbH & Co. , 2005 , Article)
      The dielectric spectroscopy of metal�metal sulfate LiRbSO4 samples are described with particular emphasis on sensor performance to be used in the field of radiation. The obtained results as the effect of different electron ...

    • TESTING SYMMETRY USING A TRIMMED LONGEST RUN STATISTIC 

      Baklizi, A. ( Blackwell Publishing Asia Pty Ltd. , 2007 , Article)
      A distribution-free test is proposed for the symmetry of a continuous distribution about a specified median. The test is based on a longest run statistic on the upper portion of the sequence of ordered �centred� observations ...

    • On Transformations and Perturbations of Orthogonal r-Frames 

      Sherif, N. ( WILEY-VCH Verlag GmbH & Co. , 1993 , Article)
      A decomposition of Cn into a finite direct sum of orthogonal subspaces can be conveniently represented by its orthogonal projector frame, which is the collection of the corresponding orthogonal projectors. Two such ...

    • Absolute evaluation of ferrous and ferric concentration in Ca amphibole 

      Bahgat, A. A.; Fayek, M. K. ( WILEY-VCH Verlag , 1982 , Article)
      Studies are made of M?sshauer absorption of 57Fe in a Ca-amphibole schist sample at room and liquid nitrogen temperatures. The absolute concentration and the recoilless fraction for ferrous and ferric cations are determined ...

    • Gamma irradiation effects on polymethyl methacrylate 

      Al-Qaradawi, I. Y.; Abdulmalik, D. A.; Madi, N. K.; Almaadeed, M. ( WILEY-VCH Verlag , 2007 , Article)
      The effect of gamma-irradiation on the structure of polymethyl methacrylate (PMMA) has been investigated. In this study, the PMMA specimens were gamma-irradiated at doses in the range of 0-1000 kGy and measured by means ...

    • On stability of equilibrium points in nonlinear fractional differential equations and fractional Hamiltonian systems 

      Keshtkar, F.; Erjaee, G.; Boutefnouchet, M. ( Wiley Periodicals, Inc.� , 2014 , Article)
      In this article, a brief stability analysis of equilibrium points in nonlinear fractional order dynamical systems is given. Then, based on the first integral concept, a definition of planar Hamiltonian systems with fractional ...

    • On the Valence State of Iron in Sr0.52+Ca0.52+Fe0.54+ Me0.54+O32− 

      Fayek, M. K.; Elnimr, M. K.; El Hamalawy, A.; Sekina, M. A. ( WILEY-VCH Verlag GmbH & Co. , 1989 , Article)
      Powder samples of Sr0.5Ca0.5Fe0.5Me0.5O3 (Me = Co, Zr or Mn) and Sr0.3La0.7FeO3 are investigated by X-ray diffraction and Mossbauer effect spectroscopy. Analysis of the completely ordered spectra suggested three kinds ...

    • The Influence of Cation Substitution on the Magnetic Behaviour of Magnesium Ferrite 

      Fayek, M.; Elnimr, M.; Nada, N.; Saleh, H.; Eid, Y. ( WILEY-VCH Verlag GmbH & Co. , 1989 , Article)
      New polycrystalline specimens of the ferrites Mg1.5Fe1Si0.5O4, Mg1.5Fe1Ge0.5O4, Mg1.5Fe1Ti0.5O4 and Mg1.66Fe1Sb0.33O4 have been prepared and studied by nuclear gamma ray resonance technique, over a wide temperature range. ...

    • Outlier robust nonlinear mixed model estimation 

      Williams, J. D.; Birch, J. B.; Abdel-Salam, A.-S. G. ( John Wiley & Sons, Ltd. , 2015 , Article)
      In standard analyses of data well-modeled by a nonlinear mixed model, an aberrant observation, either within a cluster, or an entire cluster itself, can greatly distort parameter estimates and subsequent standard errors. ...

    • Regression estimator under inverse sampling to estimate arsenic contamination 

      Moradi, M.; Salehi, M.; Brown, J. A.; Karimi, N. ( John Wiley & Sons, Ltd , 2011 , Article)
      The fate of arsenic introduced to the environment as a result of the natural and human activities is an important issue. Surveys of arsenic typically involve sampling from a large area. Measuring arsenic concentrations in ...