Lubricant film thickness variations in frictionless bearings

The possibilities are considered of diagnostics and monitoring of the technical state of frictionless bearings on the basis of the analysis of on-line recorded and processed oscillations of the lubricant film thickness. A possibility is shown of a significant increase in the monitoring efficiency when using the technique of automated processing of the diagnostic data received by using modern microprocessor means. Implementation of the proposed methodical approach will significantly shorten the duration of the frictionless bearing tests and will make it possible to govern the operating mode of the bearings in order to prolong their operation life.     

Contribution of surface treatments by esterification and silanization in reinforcing the composites based on Pine cone and Spartium junceum flours and polypropylene

Pine cone and Spartium junceum are readily available cellulosic materials which can be used as reinforcements in thermoplastic-based composites. In the present study, flours issued from Pine cone (PCF) and Spartium junceum (SjF) were first chemically modified with maleic anhydride (MA) and silane. Then, neat and treated flours were incorporated into a polypropylene (PP) matrix and the properties of composites prepared without or with maleic anhydride-grafted-polypropylene (PP-g-MA), added as a compatibilizer, were compared. FTIR analysis proved the efficiency of the treatments in removing some non-cellulosic components and formation of ester linkages due to the reaction between MA and the flours hydroxyl groups. In the case of Silane-PCF, the bands observed around 1730?cm^?1 and 1241?cm^?1 disappeared, thus indicating that the silane treatment allowed the extraction of hemicellulose and lignin from the flour surface. X-rays diffraction results showed that the applied chemical treatments contributed in increasing the flours crystallinity index, which implies that by the removal of the amorphous material covering the fibers, the more crystalline cellulosic component of the fibers is exposed. The incorporation of PCF and SjF increased the composites crystallinity which emphasizes their significant role in heterogeneous nucleating of PP matrix. Additionally, the composites observation by electron microscopy revealed more intimate contact between the flours and PP matrix after surface modification which permitted the dissolution of impurities. As a result, treated PCF and SjF induced a significant increase in the composites resilience and decreased notably their water uptake aptitude relatively to the composites based on untreated flours.     

Discovery of isoerianin analogues as promising anticancer agents

The cytotoxic activity of a series of 23 new isoerianin derivatives with modifications on both the A and B rings was studied. Several compounds exhibited excellent antiproliferative activity at nanomolar concentrations against a panel of human cancer cell lines. The most cytotoxic compound, isoerianin ( 3 ), strongly inhibits tubulin polymerization in the micromolar range. Moreover, isoerianin leads to G₂/M phase cell‐cycle arrest in H1299 and K562 cancer cells, and strongly induces apoptosis. Isoerianin also disrupts the vessel‐like structures formed by human umbilical vein endothelial cells (HUVECs) in vitro, suggesting that this compound may act as a vascular disrupting agent. It clearly appears that in this compound series, the 1,1‐ethane bridge encountered in isoerianin derivatives can replace the 1,2‐ethane bridge of natural erianin with no loss of activity. This reinforces the bioisosteric replacement approach in the combretastatin series previously reported by our research group.     

Study of corrosion inhibition properties of Schinus molle essential oil on carbon steel in HCl

The inhibitory action of Schinus molle L. essential oil was investigated for the corrosion of carbon steel in 1 M hydrochloric acid solution using weight loss, polarization curves, and electrochemical impedance spectroscopy. The inhibition efficiency has increased with the increase of the inhibitor concentration, reaching a value of up to 70% at 2 g/L.     

A combined support vector machine-FCGS classification based on the wavelet transform for Helitrons recognition in C.elegans

Multimedia Tools and Applications - The Helitrons, an important sub-class of the transposable elements (TEs) class II, have been revealed in diverse eukaryotic genomes. They are mobile elements...     

Ginzburg-Landau方程的齐次化

本文研究了Ginzburg-Landau边值问题加罚齐次化方程解的存在唯一性,文中通过引入两个参数ε和δ,分别研究ε→0和δ→0时,上述方程解的渐近性态得到的。     

Energy dispersive X-ray analysis on supported metallic clusters generated by redox processes on graphite intercalation compounds

Two types of reactions, the reduction of NiBr₂ with KC₈ in THF at room temperature and the reduction of CuCl₂—NiCl₂—GIC with potassium vapor at 300°C, were carried out in order to obtain fine metallic particles supported on the graphite matrix. The reaction products were analyzed by using XRD, SEM, and EDS. In the first reaction, EDS analysis showed that the elements of K, Br and Ni locate mainly on the surface of the graphite flakes, while XRD showed the chemical form of these elements to be metallic Ni and KBr. KBr as a by-product was easily removed by washing with aqueous medium. In the second reaction, on the other hand, EDS spectra showed that a large amount of K and Cl exist on the surface of the as-prepared sample, while almost no metallic elements, such as Ni and Cu, were found on the surface. Even after washing with 2N HCl, KCl was still identified by EDS and XRD, although the relative intensities of Ni and Cu lines in the EDS spectrum increased. It was concluded that most of the reaction products Ni, Cu and KCl are included in the graphite matrix.