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Search Results: 1 - 10 of 1632 matches for " Jacek Guzik "
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Galaxy-dark matter correlations applied to galaxy-galaxy lensing: predictions from the semi-analytic galaxy formation models
Jacek Guzik,Uros Seljak
Physics , 2000, DOI: 10.1046/j.1365-8711.2001.04081.x
Abstract: We use semi-analytic models of galaxy formation combined with high resolution N-body simulations to make predictions for galaxy-dark matter correlations and apply them to galaxy-galaxy lensing. We analyze cross-correlation spectra between the dark matter and different galaxy samples selected by luminosity, color or star formation rate. We compare the predictions to the recent detection by SDSS. We show that the correlation amplitude and the mean tangential shear depend strongly on the luminosity of the sample on scales below 1 Mpc, reflecting the correlation between the galaxy luminosity and the halo mass. The cross-correlation cannot however be used to infer the halo profile directly because different halo masses dominate on different scales and because not all galaxies are at the centers of the corresponding halos. We compute the redshift evolution of the cross-correlation amplitude and compare it to those of galaxies and dark matter. We also compute the galaxy-dark matter correlation coefficient and show it is close to unity on scales above r > 1 Mpc for all considered galaxy types. This would allow one to extract the bias and the dark matter power spectrum on large scales from the galaxy and galaxy-dark matter correlations.
Tests of Gravity from Imaging and Spectroscopic Surveys
Jacek Guzik,Bhuvnesh Jain,Masahiro Takada
Physics , 2009, DOI: 10.1103/PhysRevD.81.023503
Abstract: Tests of gravity on large-scales in the universe can be made using both imaging and spectroscopic surveys. The former allow for measurements of weak lensing, galaxy clustering and cross-correlations such as the ISW effect. The latter probe galaxy dynamics through redshift space distortions. We use a set of basic observables, namely lensing power spectra, galaxy-lensing and galaxy-velocity cross-spectra in multiple redshift bins (including their covariances), to estimate the ability of upcoming surveys to test gravity theories. We use a two-parameter description of gravity that allows for the Poisson equation and the ratio of metric potentials to depart from general relativity. We find that the combination of imaging and spectroscopic observables is essential in making robust tests of gravity theories. The range of scales and redshifts best probed by upcoming surveys is discussed. We also compare our parametrization to others used in the literature, in particular the gamma parameter modification of the growth factor.
Lensing effect on polarization in microwave background: extracting convergence power spectrum
Jacek Guzik,Uros Seljak,Matias Zaldarriaga
Physics , 1999, DOI: 10.1103/PhysRevD.62.043517
Abstract: Matter inhomogeneities along the line of sight deflect the cosmic microwave background (CMB) photons originating at the last scattering surface at redshift $z \sim 1100$. These distortions modify the pattern of CMB polarization. We identify specific combinations of Stokes $Q$ and $U$ parameters that correspond to spin 0,$\pm 2$ variables and can be used to reconstruct the projected matter density. We compute the expected signal to noise as a function of detector sensitivity and angular resolution. With Planck satellite the detection would be at a few $\sigma$ level. Several times better detector sensitivity would be needed to measure the projected dark matter power spectrum over a wider range of scales, which could provide an independent confirmation of the projected matter power spectrum as measured from other methods.
Hydroxyalkylation of Cyclic Imides with Oxiranes. Part II. The Mechanism of Reaction in Presence of Triethylamine  [PDF]
Jacek Lubczak
Open Journal of Physical Chemistry (OJPC) , 2012, DOI: 10.4236/ojpc.2012.22013
Abstract: The mechanism of reaction of cyclic monoimides with oxiranes was established based upon kinetic studies and product analysis. It has been established that the reaction proceeds through initial formation of an adduct of imide and triethylamine. The crucial bond in adduct has ionic character; in non-aqueous solvents it is present as ion pair, while in water the adduct dissociate and free ions are present. The adduct enables the proton transfer from imide to oxirane. The rate determining step is reaction of imide and this adduct. Different values of entropy of transition states obtained from thermodynamic calculations suggest slightly different structure of transition state of rate determining step.
Hydroxyalkylation of Cyclic Imides with Oxiranes Part I. Kinetics of Reaction in Presence of Triethylamine as Catalyst  [PDF]
Jacek Lubczak
Open Journal of Physical Chemistry (OJPC) , 2012, DOI: 10.4236/ojpc.2012.22012
Abstract: Literature describes kinetics of reactions of alcohols, phenols, carboxylic acids, amines and amides with oxiranes such as ethylene oxide and propylene oxide. However, there is no information regarding kinetic of reaction of imides with oxiranes. In this article the kinetics of the reaction of cyclic monoimides: succinimide, phtalimide, and glutarimide, with ethylene and propylene oxides in presence of triethylamine in aprotic solvent was studied. The rate laws for those processes were established based upon on dilatometric measurements. I was said that cyclic monoimides react with oxiranes in presence of triethylamine to give N-(2-hydroxyalkyl)imides as major product. This product react further with oxiranes in consecutive reaction. The kinetics of the reaction of cyclic mono-imides with oxiranes obey the following rate law: V = k1/2 c1/2cat c3/2imide c1/2oxirane. Based upon kinetic data the following orders of reactivity of imides and oxiranes were obtained: phtalimide ≥ succinimide > glutarimide and ethylene oxide > propylene oxide. The solvent (DMF, DMSO and dioxane) effect was also studied. From temperature dependences the thermodynamic parameters: activation energy, enthalpy and entropy from linear Eyring plots were obtained.
Structure and mechanical properties as well as application of high quality vermicular cast iron
E. Guzik
Archives of Foundry Engineering , 2010,
Abstract: The results of studies on the use of magnesium alloy in modern cored wire injection method and Tundish for production of vermiculargraphite cast irons were described. The injection of Mg cored wire length is a treatment method which can be used to process iron meltedin an electric induction furnace. This paper describes the results of using a high-magnesium ferrosilicon alloy in cored wire (Mg recovery55%) for the production of high quality vermicular graphite cast irons at foundry. The results of calculations and experiments haveindicated the length of the cored wire to be injected basing on the initial sulfur content and weight of the treated melt. The paper presents a microstructure matrix and vermicular graphite in standard sample and castings with different wall thickness. The results of numerous trials have shown that the magnesium cored wire process can produce high quality vermicular graphite with ferritic-pearlite and pearlitic-ferrite matrix irons under the specific industrial conditions.
Quality and Cost Assessment of Treatment with SiMg and NiCuMg Master Alloys vs Cored Wire in Production of Ductile Iron
E. Guzik
Archives of Foundry Engineering , 2007,
Abstract: The results of studies on the use of magnesium alloy in modern cored wire injection method for production of nodular and vermicular graphite cast irons were described. The injection of Mg cored wire length is a treatment method which can be used to process high sulphur cupola iron held in ladles or iron melted in an electric induction furnace. This paper describes the results of using a high-magnesium ferrosilicon alloy in cored wire (Mg recovery 47-70% ) for the production of vermicular and nodular graphite cast irons at cinawka Foundry, and for the production of nodular graphite iron at the following foundries: GZUT, KRAKODLEW, Centrozap - DEFKA, EE Zawiercie, WSK–Rzeszów, FWM PRZYSUCHA, HSW Stalowa Wola and PIOMA. The results of calculations and experiments have indicated the length of the cored wire to be injected basing on the initial sulfur content and weight of the treated melt. The results of numerous trials have shown that the magnesium cored wire process can produce high quality nodular and vermicular graphite irons under the specific industrial conditions of the above mentioned foundries. It has also been proved that in the manufacture of nodular graphite iron, the cost of the nodulariser in the form of elastic cored wire is lower than the cost of the FeSiMg or NiCuMg master alloys.
Analysis of quality and cost of FeSiMg treatment master alloy vs. cored wire in production of ductile cast iron
E. Guzik
Archives of Foundry Engineering , 2008,
Abstract: The results of studies on the use of FeSi5%Mg magnesium alloy in modern cored wire injection method for production of nodular and vermicular graphite cast irons were described. The injection of Mg cored wire length is a treatment method which can be used to process The injection of Mg cored wire length is a treatment method which can be used to process iron melted in an electric induction furnace. This paper describes the results of using a high-magnesium ferrosilicon alloy in cored wire (Mg recovery 47-70%) for the production of vermicular and nodular graphite cast irons at in at least 13 foundries. The results of calculations and experiments have indicated the length of the cored wire to be injected basing on the initial sulfur content and weight of the treated melt. The results of numerous trials have shown that the magnesium cored wire process can produce high quality nodular and vermicular graphite irons under the specific industrial conditions of the above mentioned foundries. It has also been proved that in the manufacture of nodular graphite iron, the cost of the nodulariser in the form of elastic cored wire is lower than the cost of the FeSiMg5 master alloys.
Rehabilitation of an Existing Office Block  [PDF]
Tomasz Blaszczynski, Jacek Wdowicki
Engineering (ENG) , 2011, DOI: 10.4236/eng.2011.39107
Abstract: A new owner wishes to refurbish the analysed building assembled in 70’s to modern intelligent office block and to develop up to 3000 m2 of a new part. The old office building has been in use until late 80’s. First two floors are made as a monolithic and the rest are prefabricated as RC frame with the shear walls in both directions. All aspects, which came from the coexistence of an old and new part of the office block, will be the scope of an article. The BW for Windows program has been used for computations. In our paper models of shear wall structures in the modernised part as well as the new adjacent part have been shown. The short period of time necessary to obtain the results of the analysis has allowed for a fully interactive structural design. Many analyses have been created to estimate structural space stiffness for existing and new part of the building. Analysis showed, that existing part deflections were 7 times less then permissible one and after concrete grade of a new part has been changed, deflections for both parts were almost the same.
Capability of the Free-Ion Eigenstates for Crystal-Field Splitting  [PDF]
Jacek Mulak, Maciej Mulak
Journal of Modern Physics (JMP) , 2011, DOI: 10.4236/jmp.2011.211170
Abstract: Any electronic eigenstate of the paramagnetic ion open-shell is characterized by the three independent multipole asphericities for and 6 related to the second moments of the relevant crystal-field splittings by , where . The Ak as the reduced matrix elements can serve as a reliable measure of the state capability for the splitting produced by the k-rank component of the crystal-field Hamiltonian. These multipolar characteristics allow one to verify any fitted crystal-field parameter set by comparing the calculated second moments and the experimental ones of the relevant crystal-field splittings. We present the multipole characteristics Ak for the extensive set of eigenstates from the lower parts of energy spectra of the tripositive 4 f N ions applying in the calculations the improved eigenfunctions of the free lanthanide ions obtained based on the M. Reid f-shell programs. Such amended asphericities are compared with those achieved for the simplified Russell-Saunders states. Next, they are classified with respect to the absolute or relative weight of Ak in the multipole structure of the considered states. For the majority of the analyzed states (about 80%) the Ak variation is of order of only a few percent. Some essential changes are found primarily for several states of Tm3+, Er3+, Nd3+, and Pr3+ ions. The detailed mechanisms of such Ak changes are unveiled. Particularly, certain noteworthy cancelations as well as enhancements of their magnitudes are explained.
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