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Editorial

Corrigendum: F. García-Garmilla, I. Rodríguez Maribona, M. Cano, M. Zalbide, J. A. Ibáñez-Gómez, E. Osa-Chans, S. Garín (2002), Materiales de Construcción, Vol 52, No 266: 12

Erratum

Calculo de Parámetros Electrónicos Para el Grafito Bernal

Using ab-initio calculation, we have computed different electronic parameters associated with the transport coefficients of graphite Bernal. Software CRYSTAL¹ was used with a Pople standard STO- 21G* basis set. Different hamiltonians were tested, choosing a restricted Hartree-Fock one, because it generated the best qu…

Estimation of the Plain High-Cycle Fatigue Propagation Resistance in Steels

In this work a method to estimate the high cyclic fatigue propagation life of steel specimens under constant loading is presented. This method is based in experimental evidence that the fatigue limit represents the threshold stress for the propagation of nucleated cracks, so that both the fatigue limit and the fatigue…

Experimental and Numerical Investigation Into Metallocene Polymer Melt Flow in Film Blowing Dies

A frequent problem in the production of metallocene linear low-density polyethylene (mLLDPE) films is the occur-rence of flow instabilities, e.g. sharkskin, or degradation of material, which limit the production rate and decrease the product quality. If such problems arise, the question is what causes these phenomena…

Rheological Interpretation of the Slump Test

We examine the validity of the slump test for predicting the yield stress of polymeric suspensions and mineral suspensions. First we propose a modification of this test: in order to make measurements on fluids with high yield stress (of the order of several hundreds of Pascal) we add a mass at the sample top. From det…

The Inlet Engine Valves Grinding Using Different Types of Cutting Fluids and Grinding Wheels

In this paper an experimental research is presented in which different types of cutting fluids (a cutting oil and three different types of soluble oils) and grinding wheels (alumina and vitrified CBN) were tested in the inlet engine valves grinding. As evaluation parameters the workpiece residual stress and the grindi…

Surface modification of fique fibers. Effect on their physico‐mechanical properties

Abstract A study has been performed to assess the possibilities of fique fibers (a Colombian native fiber) as reinforcement for polymeric matrices. The fique fibers were treated using different chemical surface treatments. The effect produced on the physico‐mechanical properties of fique fibers have been investigated.…

Local Approach to Fracture of an Aged Duplex Stainless Steel

The local approach to fracture (LAF) is a methodology aimed to calculate macroscopic fracture properties of a body, from the knowledge of the local stress - strain field at the fracture site, and the modeling of the acting fracture mechanisms. In the present work, this method was applied to a CF8M steel, aged 30000h a…

Identification of components in smectite/kaolinite mixtures

Abstract Mechanically-prepared binary mixtures of two dioctahedral smectites (of different chemical compositions) with two kaolinites (with different amounts of structural defects) were studied by infrared (IR) spectroscopy to verify the ability of IR spectroscopy to detect small amounts of individual components in th…

Biomaterials and Scaffolds in Reparative Medicine

Most approaches currently pursued or contemplated within the framework of reparative medicine, including cell-based therapies, artificial organs, and engineered living tissues, are dependent on our ability to synthesize or otherwise generate novel materials, fabricate or assemble materials into appropriate 2-D and 3-D…

DAILY FLUCTUATIONS OF EXOPOLYMERS IN CULTURES OF THE BENTHIC DIATOMS CYLINDROTHECA CLOSTERIUM AND NITZSCHIA SP. (BACILLARIOPHYCEAE)1

Dynamics in the production of extracellular polymeric substances (EPS) were investigated for the benthic diatoms Cylindrotheca closterium (Ehrenberg) and Nitzschia sp. The effect of growth phase and light:dark conditions were examined using axenic cultures. Two EPS fractions were distinguished. Soluble EPS was recover…

Geomagnetically Induced Current Effects on Transformers

Geomagnetically induced currents (GIC) can cause saturation of the magnetic circuit of transformers in a power system. This saturation can increase the Mvar absorption of the transformers leading to voltage control problems, generate significant harmonic currents and cause heating of the internal components of the tra…

Optical Spectroscopy Study on β-Ga2O3

Undoped β-Ga 2 O 3 single crystals were grown by the floating zone technique under different conditions, and subsequently annealed in O 2 . Excitation and luminescence measurements were correlated with optical absorption, Hall- and electron-paramagnetic resonance measurements. It is shown, that the UV luminescence doe…

Dithienylethenes with a Novel Photochromic Performance

Dithienylethenes with low decoloration quantum yields and thermal reversibility at high temperature above 100 degrees C were prepared. Introduction of bulky alkoxy substituents at 2- and 2'-positions of the thiophene rings strongly suppressed the cycloreversion quantum yields. The quantum yields were lower than 10(-3)…

Effects of axial ligands on the photophysical properties of silicon octaphenoxyphthalocyanine

The photochemistry and photophysics of six axially substituted silicon phthalocyanines are reported and show the importance of the axial groups in the photochemistry of these compounds. The fluorescence quantum yields are especially affected by the axial ligand. A very good correlation was found for the experimentally…

Corrosion Protection of Mild Steel Using Sulfonic and Phosphonic Acid-Doped Polyanilines

Growing environmental concerns regarding the use of heavy metals in coating formulations have led to a new coating strategy using inherently conducting polymers (ICP), such as polyaniline (PANI), as a key component. The principal potential advantage offered by the ICP coating technology is toleration of pinholes and m…

Role of the dimerized gap due to anion ordering in spin-density wave phase of (TMTSF)$_2$ClO$_4$ at high magnetic fields

Magnetoresistance measurements have been carried out along the highly conducting a axis in the FISDW phase of hydrogened and deuterated (TMTSF)$_2$ClO$_4$ for various cooling rates through the anion ordering temperature. With increasing the cooling rate, a) the high field phase boundary $β_{\rm {HI}}$, observed at 27…

Conformational features of crystal‐surface cellulose from higher plants

Native cellulose in higher plants forms crystalline fibrils a few nm across, with a substantial fraction of their glucan chains at the surface. The accepted crystal structures feature a flat-ribbon 21 helical chain conformation with every glucose residue locked to the next by hydrogen bonds from O-3' to O-5 and from O…