Search results for "medium"

Adhesion and interfacial reactions on metal/oxide interface during plastic deformation at room temperature

2005

Properties of interfaces in solid state metal/oxide joints (Al/SiO2, Al/MgO, Al/glass, Mg/MgO, Mg/SiO2, In/glass etc.) are reported. The interfaces were formed at plastic deformation of metal on the oxide surface at room temperature. Their structure, chemical composition, and micromechanical properties were studied by the AFM, XRD, SIMS, optical microscopy, and precision microindentation techniques. A noticeable adhesion was observed for metals with high affinity for oxygen and only in the regions of the maximum shear stress. Formation of an interfacial reaction zone with an oxygen concentration gradient is detected. In this zone metals are nanostructured and noticeably hardened. The effect…

Conditioned media from adipose stem cells down-regulates senescence induced by interleukin-1β in osteoarthritic chondrocytes

2016

Determination and separation of diarylheptanoids from alder growing in Latvia

2015

The composition of diarylhepatnoids fraction isolated from bark of two alder species (grey alder and black alder) was studied. The efficiency of three extraction methods used for isolation of diarylhepatnoids from alder bark was compared. Two diarylhepatnoids: 1,7-bis-(3,4-dihydroxyphenyl)-heptan- 3-one-5-O-β-D-xylopyronoside (oregonin) and 1,7-bis-(3,4-dihydroxyphenyl)-3-hydroxyheptane-5-O-β-D- xylopyranoside were isolated from the bark of grey alder. The phenolic components of the extracts were analyzed by high-performance liquid chromatography (HPLC). Quantitative determination of oregonin was performed using an internal standard method. The results obtained show that alder barks are ric…

Drivers and dynamic processes for SMEs going global

2006

PurposeMany, if not most, small to medium‐sized enterprises (SMEs) are subject to the impacts of globalisation. This article seeks to explore the extra dimension of challenge to their already difficult environments when they have to venture into the world‐trade system.Design/methodology/approachRecent research undertaken separately by Polish, Italian, Norwegian and UK collaborators examined eight case studies of disparate smaller companies with international operations. This article brings together the common features found, and discusses them in terms of structural drivers and dynamic implications.FindingsResearch findings include the stretching of capabilities in supporting customers in u…

INTERNATIONALISATION OF SMALL AND MEDIUM SICILIAN WINERIES: AN EXPLORATORY STUDY BASED ON THE RBV APPROACH

2014

Strategies of internationalization, such as export, have a central role as well to safeguard the market position and survival for many enterprises, including small and medium ones. The aim of this study is to investigate, through a resource-based view (RBV) approach, the main firms' internal factors that affect the export propensity of sparkling wines producers in Sicily and their ability to insert into foreign market. Based on review of extant literature we have identified the main factors, related both to the firms and to the managers characteristics, that affect the firm performance in the export market. Using survey data of 94 Sicilian small and medium wineries export oriented, this pap…

Theoretical rotational constants of MeCnN species

1990

Abstract By means of SCF HF “ab initio” calculations with STO-3G and 6-31G basis sets, the geometric parameters of methylcyanopolyynes (MeCnN n=3, 5, 7 and 9) have been obtained. B0=0.3748 GHz for MeC7N and B0=0.2708 GHz for MeC9N, with a STO-3G basis set, were obtained. Both species, unstable in the laboratory, are still undetected in the interstellar medium, although their existence is very probable.

Experimental and numerical evaluation of sandwich composite structures

2004

The main problem working with sandwich composite structures is their intrinsic anisotropy and non-homogeneity that does not allow their correct modelling. Nowadays the available data on mechanical properties of complex structures, necessary to allow a correct and reliable design, are not sufficient. The aim of the present work is to extend the knowledge of mechanical properties both on single components and on complete structures, focusing on the effects induced by different kind of skin arrangements (Kevlar, glass and carbon fibres). Compressive, shear and flexural tests were performed for a complete static mechanical characterisation of the sandwich structure both on each single component…

Liquid intrusion and alternative methods for the characterization of macroporous materials (IUPAC Technical Report)

2011

This document deals with the characterization of porous materials having pore widths in the macropore range of 50 nm to 500 μm. In recent years, the development of advanced adsorbents and catalysts (e.g., monoliths having hierarchical pore networks) has brought about a renewed interest in macropore structures. Mercury intrusion–extrusion porosimetry is a well-established method, which is at present the most widely used for determining the macropore size distribution. However, because of the reservations raised by the use of mercury, it is now evident that the principles involved in the application of mercury porosimetry require reappraisal and that alternative methods are worth being listed…

Study of the Interaction Mechanism in the Biosorption of Copper(II) Ions onto Posidonia oceanica and Peat

2012

A systematic approach was used to characterize the biosorption of copper(II) onto two biosorbents, Posidonia oceanica and peat, focusing on the interaction mechanisms, the copper(II) sorption–desorption process and the thermal behavior of the biosorbents. Sorption isotherms at pH 4–6 were obtained and the experimental data were fitted to the Langmuir model with a maximum uptake ( q max ) at pH 6 of 85.78 and 49.69mgg -1 , for P. oceanica and peat, respectively. A sequential desorption (SD) with water, Ca(NO 3 ) 2 , and EDTA was applied to copper-saturated biosorbents. Around 65–70% copper(II) were desorbed with EDTA, indicating that this heavy metal was strongly bound. The reversibility of …

Mass spectrometric investigations of the kinetic stability of chromium and copper complexes with humic substances by isotope-labelling experiments

1999

Isotope-labelling exchange experiments were carried out to investigate the kinetic stability of Cr(III) complexes with humic substances (HS). To compare the results with those of an ion, not expected to form kinetically stable HS complexes with respect to its electron configuration, Cu(II) was investigated under the same conditions. HS solutions of different origin were therefore spiked with 53Cr(III) or 65Cu(II) after saturation of HS with chromium and copper of natural isotopic composition. In fractions of metal/HS complexes with different molecular weight, obtained by ultrafiltration and HPLC/ICP-MS using size exclusion chromatography (SEC), respectively, the isotope ratios of chromium a…