This research investigates the effects of styrene-butadiene-styrene (SBS) copolymer and other plastomers on the behavior of Saudi bitumen. Three bitumen samples, extracted from three Saudi oil refineries, namely Ras Tanura, Riyadh, and Yanbu, were used in this study. The bitumen samples were mixed with different modifiers in various compositions, forming polymer modified bitumens (PMBs). Elasticit

Different designs of the SX-700 plane grating monochromator have been investigated for the undulator beamline (51) by using analytical considerations and carrying out ray tracing calculations. The most important modifications of the original design are those where the ellipsoidal focusing mirror has been replaced by a plane elliptical or by a spherical mirror. A significant advantage of the spheri

The electronic structure of Ca in the high-temperature superconductor Bi2Sr2CaCu2O8 has been studied by x-ray-absorption spectroscopy and resonant-photoemission at the Ca L2,3 absorption edge. In the x-ray-absorption spectrum no edge structure is seen at the energy corresponding to the Ca 2p3/2 core-level binding energy, in agreement with the very low Ca density of states at the Fermi level predic

Ordered structures formed by Na adsorption on the Al(111) surface are investigated by high-resolution core-level spectroscopy. It is shown that, contrary to the common picture of alkali adsorption, two of the structures formed at room temperature consist of intermixed Na-Al layers. The results for the (3 ×)-rotated-30°structure are also consistent with intermixing although they do not provide any

The 1s to 2π* resonances have been studied for CO strongly chemisorbed on Ni(100) and weakly chemisorbed on Cu(100) using high resolution X-ray absorption spectroscopy. We show that the spectra can be consistently described in terms of the local density of unoccupied 2π* electron states with the Fermi level obtained from corresponding X-ray photoelectron spectra. The core hole is demonstrated to i

Soft x-ray emission spectroscopy is for the first time applied to surfaces and adsorbates. Surface sensitivity is achieved by employing synchrotron radiation in grazing incidence for the excitation. We present O K emission from adsorbed atomic oxygen on Ni(100) and Cu(100) and molecular CO on Ni(100). The observed spectral features correspond to the occupied 2p partial density of states of the ads

In this paper we present a study of the interaction of Pb with a clean single-crystal Bi2CaSr2Cu2O8 superconductor surface based on photoemission and low-energy electron diffraction (LEED). Deposition of Pb on a Bi2CaSr2Cu2O8 crystal kept at room temperature gives rise to the formation of metallic Bi and oxidized Pb at the interface. This behavior could not be observed when the crystal was kept at

The surface core-level shifts of the Al(100) and Al(111) surfaces have been measured by high-resolution photoelectron spectroscopy. For the Al(100) surface we obtain a value of (-965) meV. This value is in excellent agreement with a recent ab initio calculation by Feibelman. The surface core-level shift of the Al(111) surface is found to be close to zero, and an upper limit of 15 meV is obtained.

The formation of the Cu-Bi2CaSr2Cu2O8 interface has been studied by photoelectron spectroscopy using synchrotron radiation. Photon energies in the range 20-1000 eV were utilized in order to probe both the valence band and to monitor chemical changes upon Cu deposition, as revealed by the core-level shifts. A strong chemical reaction between Bi2CaSr2Cu2O8 and Cu is manifested by the formation of me

The bonding energies of the Pd 3d and the C 1s core levels have been studied for the p(2 S 2 × 2) R45°, p(3 s2 × S2) R45°, and p(4 S 2 × S 2) R45°structures of CO on Pd(100). Adsorption of CO shifts the Pd 3d surface emission to higher binding energies with the magnitude of the shift depending almost linearly on the number of Pd to CO bonds; the measured shift per bond is close to 0.5 eV. A direct

Purpose – This paper investigates the experiences of school teachers of supporting pupils and their apprehensions of how pupils search and assess information when search engines have become a technology of literacy in schools. By situating technologies of literacy as sociomaterial the purpose of this paper is to analyse and discuss these experiences and understandings in order to challenge dominan

Energy distributions of slow electrons (0-10 eV) emitted by thin layers of NaCl, KBr, CsBr, and CsI irradiated by monochromatic XUV photons with various energies in the interval of 50-300 eV are measured. The contributions of slow secondaries, hot secondaries and primary photoelectrons are obtained. It is shown that the higher the absorption coefficient for incident photons, the stronger the contr

I detta arbete har två analysmetoder med mycket hög känslighet för att mäta väte och bor utvecklats. Dessa har tillämpats på geologiska material där de kan vara ett verktyg i att svara på frågeställningar gällande b.la. jordskorpans utveckling och flödet av vatten på jorden. Metoderna kan mäta en väte- eller bor-atom bland en miljon andra atomer. Jonstråleanalys är ett fält inom den tillämpade fys