Structural and mechanical properties of Al–C–N films deposited at room temperature by plasma focus device

The Al–C–N films are deposited on Si substrates by using a dense plasma focus(DPF) device with aluminum fitted central electrode(anode) and by operating the device with CH_4/N_2 gas admixture ratio of 1:1. XRD results verify the crystalline Al N(111) and Al_3CON(110) phase formation of the films deposited using multiple shots. The elemental compositions as well as chemical states of the deposited Al–C–N films are studied using XPS analysis, which affirm Al–N, C–C, and C–N bonding. The FESEM analysis reveals that the deposited films are composed of nanoparticles and nanoparticle agglomerates. The size of the agglomerates increases at a higher number of focus deposition shots for multiple shot depositions. Nanoindentation results reveal the variation in mechanical properties(nanohardness and elastic modulus)of Al–C–N films deposited with multiple shots. The highest values of nanohardness and elastic modulus are found to be about 11 and 185 GPa, respectively, for the film deposited with 30 focus deposition shots. The mechanical properties of the films deposited using multiple shots are related to the Al content and C–N bonding.     

MHD natural convective flow through a porous medium in a square cavity filled with liquid gallium

This article contains a computational study of free convective flow through a square enclosure filled with liquid gallium saturated porous medium in the presence of a uniform inclined magnetic field. Lower boundary of enclosure is considered to be heated uniformly, upper horizontal boundary is taken insulated, left wall of the cavity is heated linearly, and right wall is heated linearly or taken cold. Navier–Stokes equations governing the flow problem are first exposed to penalty method to eliminate the pressure terms and then Galerkin FEM is employed to solve reduced equations. Grid independent results are achieved and shown in tabular form for numerous ranges of physical flow parameters. To ensure the accuracy of developed code, computed results are compared with those available in earlier studies through figures. It is found that the strength of streamlines circulation is increased due to increase in Darcy number while imposition of vertical magnetic field instead of horizontal magnetic field causes slow rate of increase in strength of streamlines circulation. Whereas, in the case of linearly heated right wall, the average Nusselt number is an increasing function of the Darcy number, and vertical magnetic field causes higher values for average Nusselt number as compared to horizontal magnetic field along bottom and side walls of cavity. Contrarily, in the case of cold right wall, the horizontal magnetic field results in higher values of average Nusselt number as compared to the vertical magnetic field case, and the average Nusselt number reduces as we move along lower and right boundary while increases along left wall with increase in distance.     

Phosphorescence properties of sol–gel derived ruby measured as functions of temperature and Cr<Superscript>3+</Superscript> content

A novel approach for the contactless measurement of surface temperatures is to evaluate the temperature dependent phosphorescence properties of chromium doped aluminium oxide (ruby) coatings, such as phosphorescence intensity, spectral distribution, or the phosphorescence lifetime. However, these properties are also affected by the chromium content in the films. In the present study the phosphorescence lifetimes were studied for the first time as a function of the chromium content. We use a simple sol–gel depositing technique for the preparation of precisely doped ruby coatings in Si(100) substrates. These coatings (Cr-to-Al-ratios y between 0% and 6.8 at. %) are well suited for studying the influence of the chromium concentration on the phosphorescence properties: at room temperature (294 K), the phosphorescence intensity is strongly affected by the chromium doping (maximum at y∼1–1.5%) while the spectrum shifts only slightly with varying chromium content. The phosphorescence lifetime τ at 294 K remains constant with varying Cr³⁺ content below y∼1.1%, and decreases strongly above y∼1.1%. Thus, ruby doped with y∼1% seems to be most promising as a temperature sensor because it shows the highest phosphorescence intensity and a low variance in the phosphorescence lifetimes. Due to the latter property the temperature evaluation from τ is less affected by imprecise doping. The phosphorescence lifetimes of several sol–gel ruby coatings (y=1.1%) on Si(100) substrates were measured as a function of the temperature to be between 2.7 ms at 294 K and 4 μs at 833 K. PACS 07.20.Dt; 78.55.-m; 78.66.-w     

Synthesis and evaluation of pyrazole‐incorporated monocarbonyl curcumin analogues as antiproliferative and antioxidant agents

A series of pyrazole‐incorporated monocarbonyl analogues of curcumin were synthesized via Clasien–Schimidt‐type condensation and subsequently screened for in vitro antiproliferative and antioxidant activity. The analogues 4c, 5d, 5e, 5g, 6e, and 6f showed potential activity against the MDA‐MB‐231 cell line. The synthesized analogues were also screened for their antioxidant activity. Compounds 5a , 5e , 6d, and 6f exhibit comparable radical scavenging activity with respect to the standard drug ascorbic acid. Furthermore, a molecular docking study has been conducted for 5d and 5g and suggests that these compounds have a potential to become lead molecules in drug discovery and process.     

Treatment of Silylene–Phosphinidene with Chalcogens Resulted Exclusively in the Formation of Silicon-Bonded Chalcogens

Chalcogen-bonded silicon phosphinidenes LSi(E)−P−^MecAAC (E=S ( 1 ); Se ( 2 ); Te ( 3 ); L=PhC(NtBu)₂; ^MecAAC=C(CH₂)(CMe₂)₂N-2,6-iPr₂C₆H₃)) were synthesized from the reactions of silylene–phosphinidene LSi−P−^MecAAC ( A ) with elemental chalcogens. All the compounds reported herein have been characterized by multinuclear NMR, elemental analyses, LIFDI-MS, and single-crystal X-ray diffraction techniques. Furthermore, the regeneration of silylene–phosphinidene ( A ) was achieved from the reactions of 2 – 3 with L′Al (L′=HC{(CMe)(2,6-iPr₂C₆H₃N)}₂). Theoretical studies on chalcogen-bonded silicon phosphinidenes indicate that the Si−E (E=S, Se, Te) bond can be best represented as charge-separated electron-sharing σ-bonding interaction between [LSi−P−^MecAAC]⁺ and E⁻. The partial double-bond character of Si−E is attributed to significant hyperconjugative donation from the lone pair on E⁻ to the Si−N and Si−P σ*-molecular orbitals.     

Tetracyclic triterpenoids from the leaves of Azadirachta indica and their insecticidal activities

A new tetranortriterpenoid, meliatetraolenone [24,25,26,27-tetranor-apotirucalla-(apoeupha)-6alpha-O-methyl, 7alpha-senecioyl(7-deacetyl)-11alpha,12alpha,21,23-tetrahydroxy-21,23-epoxy-2,14,20(22)-trien-1,16-dione] (1) was isolated from the methanolic extract of fresh leaves of Azadirachta indica along with the known compound odoratone (3) which was hitherto unreported from this source. Their structures have been elucidated by spectral studies including 2D NMR. The insecticidal activities of 1 as well as those of odoratone (3) are reported. 1 and odoratone both showed mortality on fourth instar larvae of mosquitoes (Anopheles stephensi) with LC(50) values of 16 and 154 ppm, respectively.     

Triterpenoidal constituents of the leaves of Carissa carandas

Studies undertaken on the fresh leaves of Carissa carandas have led to the isolation of four pentacyclic triterpenoids (1-4) including one new constituent carissin (1) and two hitherto unreported compounds 2 and 3. The structure of the new triterpenoid has been elucidated as 3beta-hydroxy-27-E-feruloyloxyurs-12-en-28-oic acid. Compelete assignment of the protons of 2 has also been made based on 2D NMR studies.     

Evaluation of naphtha reforming catalysts by accelerated deactivation tests

Accelerated deactivation tests of four commercial Pt−Re/Al₂O₃ catalysts have been carried out in a pilot plant at RON values of 98–100. From this 350-hour test, specific performance data for objective comparison of catalysts were obtained.     

Certain inverse solutions of a non-Newtonian fluid

Inverse solutions of the equations of motion of an incompressible second grade or order fluid are obtained by assuming certain forms for the stream functions a priori. The equations considered are in plane polar coordinates, axisymmetric polar coordinates and in axisymmetric spherical polar coordinates. Expressions for stream lines, veiocity components and pressure distributions are given explicitly, in each case, and are compared with the corresponding results of a viscous fluid.     

The photoneutron cross section of 6Li

The photoneutron cross section of ⁶Li has been measured from threshold to 17 MeV using bremsstrahlung from an electron synchrotron. Neutrons were detected by a high-efficiency multi-BF3-counter detection system. The cross section shows broad peaks at 12 MeV and 16 MeV with no other structure apparent.