Fischer–Tropsch Synthesis: Studies on the Effect of Support Doping with Si,Mn and Cr on the Selectivity to Alcohols in Ceria Supported Cobalt Catalysts

Mn and Cr doped CeSi mixed oxides were used as supports for Co and tested for CO hydrogenation. Co/CeSi was found to be more active and significantly more selective to n-alcohols/olefins. An increasing selectivity to n-alcohols and decreasing selectivity to olefins as a function of time on stream was also observed, suggesting a trade-off between those two products. Addition of Mn led to similar behavior, although at slightly lower conversions. Addition of Cr, however, considerably suppressed n-alcohol formation, while it kept selectivities to olefins within a 20–30 % range over more than 250 h of testing, indicating either higher alcohol dehydration activity, or that the presence of Cr ions lowered the hydrogenating activity of Co. The present work indicates that enhanced contact area between Co and the reducible support is likely a key factor for enhancing selectivity to alcohols.     

Synthesis,studies of 2-benzyl-amino-4-p-tolyl-6,7-di-hydro 5H-cyclo-penta–[b]pyridine-3 carbo-nitrile (BAPTDHCPCN) crystals for optical,photonic and mechano-electronic uses

2-benzyl-amino-4-P-tolyl-6,7-di-hydro 5H-cyclo-penta –[b]pyridine–3 carbo–nitrile—BAPTDHCPCAN crystal is grown by solution growth evaporation method and analysed for XRD, Unit Cell, Dielectric analysis, UV, Tauc’s plot and fluorescence and mechano studies. The single crystalline XRD data portrays the monoclinic nature of BAPTDHCPCAN with space group P2₁/c and a, b, c as 8.6828 Å, 17.7283 Å, 12.0403 Å with β as 94.254°. Chemical formula of crystal as C₂₃H₂₁N₃. The crystalline dimension is 14?×?12x7 mm³. The dielectric properties of the BAPTDHCPCAN have larger value at low range of frequencies. The phase matching effectiveness is analyzed and found to be 66 mV. The influx value of macro and thin film of BAPTDHCPCAN crystal is 4.2125 microns and 4.4336 microns as mid value before nano shaped influx. Absorption spectral two peaks centered at 248 nm at 325 nm, the band gap of crystal is calculated as 5.0 eV by photonic enhancement and the fluorescence represented emission for 399 nm. The BAPTDHCPCAN crystal is found to have represented –ve photoconductive nature. The BAPTDHCPCAN crystal specimen in of RISE [Reverse Indentation Size Effect] consequence with n greater than 2.

     

Investigation of structural,optical, and thermal properties of 2-amino-4,6-dimethylpyrimidine benzoic acid (2APB) single crystal for non-linear optical (NLO) applications

The 2-amino-4,6-dimethylpyrimidine benzoic acid (2APB) single crystal has been successfully grown by the slow evaporation method by using water as a solvent. The single-crystal X-Ray diffraction (SXRD) analysis gives knowledge about the structure and morphology of the 2APB crystal. The Powder X-ray Diffraction (PXRD) pattern of grinded 2APB crystal was compared with standard CIF file and the peaks were indexed with their corresponding miller indices (hkl). The crystalline perfection of the grown 2APB single crystal was analysed using high-resolution X-ray diffraction (HR-XRD) measurement. The various functional groups and their vibrational assignments were studied using the Fourier-transform infrared (FTIR) spectrum analysis. The 2APB crystal has a lower cut-off wavelength of 325 nm, which is evident from the UV–visible–NIR analysis. The defects and etch pit density of 2APB crystal were examined using chemical etching studies. The 2APB crystal was thermally stable up to 140 °C, which was evident from the thermogravimetric (TG) and differential thermal analysis (DTA). The photoconductivity analysis was carried out to calculate the photo and dark current values. The laser damage threshold (LDT) value was determined using a 532 nm Nd:YAG laser in single shot mode. The third-order non-linear optical (NLO) susceptibility (χ⁽³⁾) value was calculated from Z-scan technique, which involves open and closed aperture measurements.

     

Year around distilled water production,energy, and economic analysis of solar stills—A comparative study

In this paper, a year around energy efficiency (EnE) and economic analysis of single slope solar still (SSSS), the single slope solar still with glass cooling (SSSSGC), the single slope solar still with basin heating (SSSSBH), and the single slope solar still with glass cooling and basin heating (SSSSGCBH) was carried out based on the distilled water production. The annual yield production from the SSSS, SSSSGC, SSSSBH, and SSSSGCBH were 476.16, 637.44, 970.24, and 1167.36 kg, respectively. The yearly yield produced from the SSSSBH and SSSSGCBH was increased by 50.92% and 59.21%, respectively, as compared with the SSSS. Moreover, the annual EnE of the SSSSGCBH was 28.75%. However, the EnE of the SSSS was 11.73%. Also, freshwater making cost is found to be 18.9, 24.9, 37.9, and 45.6 Rs/day for the SSSS, SSSSGC, SSSSBH, and SSSSGCBH, respectively, if the buying cost of freshwater is Rs 10.     

Relation of the concentration-time product to uptake and mortality in Sitophilus granarius treated with methyl bromide

Uptake of methyl bromide was greater at high concentrations with an exposure period of 2 hr than at lower concentrations with an exposure period of 5 hr, but mortality did not increase accordingly. Some fumigant was desorbed from insects after treatment and desorption was greater in those exposed for the shorter period. Statistical analysis on the three major variables which contribute to toxicity, namely concentration, time and fumigant uptake, showed that, for purposes of calculation, only the two factors, concentration and time, need to be considered; inclusion of data on uptake into the model did not provide appreciable contribution to explain the observed mortalities beyond that already given by concentration and time. A model which includes concentration, time and interaction between the two was found to describe the dosage-response relationship better than concentration and time alone.     

Size dependent structural, optical and morphological properties of ZnS:Cu thin films

ZnS:Cu thin films have been deposited on glass substrate by a simple neutral pH solution synthesis route and chemical bath deposition technique. The copper concentration was varied between 0 and 0.1 M%. The X-ray diffraction and scanning electron microscope studies show the average size of the nanoparticles are below 4 nm (Bohr diameter). The effect of film thickness on the optical and structural properties has been studied. The optical absorption studies show the band gap energy of ZnS:Cu films decreases from 3.68 to 3.43 eV as thickness varied from 318.3 to 334.1 nm. The structural estimation shows the variation in particle size from 2.67 to 3.14 nm with thickness. The insignificant change in band gap may be due to the increase in particle size and quantum size effect.     

Evaluation of precipitation reaction in 2024 Al-Cu alloy through ultrasonic parameters

Non-destructive diagnosis of nano-scale pre-precipitation and precipitation events can provide valuable support in controlling the thermal treatment for achieving the peak aged or any alternate desired microstructural state. The aim of the present investigation is to study the effect of isothermal ageing on density and hardness of 2024 Al-Cu-Mg alloy, and also to search the ability of measured ultrasonic velocity and attenuation and calculated elastic constants for monitoring the variations in microstructure and precipitation events during ageing. The specimens aged at 463 K for various periods up to 32 h followed by a solution annealed at 766 K for 1 h and water quenched, have been used for the ultrasonic velocity and attenuation measurements and metallurgical studies. The initial sharp acceleration in the hardness and velocities is due to the depletion of Cu from solid solution associated with the formation and growth of Cu-Mg co-cluster (GPB zone) and other intermediate phases. The local maximum at 10 h ageing time is due to the presence of higher volume fraction of precipitates like S′ and S and the minimum at 32 h of ageing time is due to the existence of dissolution and coarsening of S′ and S precipitates by overaged effect.     

N′‐Alkylaminosulfonyl Analogues of 6‐Fluorobenzylideneindolinones with Desirable Physicochemical Profiles and Potent Growth Inhibitory Activities on Hepatocellular Carcinoma

The benzylideneindolinone 6‐chloro‐3‐(3′‐trifluoromethylbenzylidene)‐1,3‐dihydroindol‐2‐one ( 4 ) was reported to exhibit potent and selective growth inhibitory effects on hepatocellular carcinoma (HCC). Corroborative evidence supported multi‐receptor tyrosine kinase (RTK) inhibition as a possible mode of action. However, the poor physicochemical properties of 4 limited its furtherance as a lead compound. In this study, the modification of 4 was investigated with the aim of improving its potency and physicochemical profile. The 6‐fluorobenzylideneindolinone 3‐12 bearing a 3′‐N‐propylaminosulfonyl substituent was found to be a promising substitute. Compound 3‐12 [6‐fluoro‐3‐(3′‐N‐propylaminosulfonylbenzylidene)‐1,3‐dihydroindol‐2‐one] was found to be tenfold more soluble than 4 and to have sub‐micromolar growth inhibitory activities on HCC cells. It is apoptogenic and inhibits the phosphorylation of several RTKs in HuH7, of which the inhibition of FGFR4 and HER3 are prominent. Compound 3‐12 decreased the tumor load in a physiologically relevant orthotopic HCC xenograft murine model. Structure–activity relationships support pivotal roles for the fluoro and N′‐propylaminosulfonyl moieties in enhancing cell‐based activity and moderating the physicochemical profile (solubility, permeability) of 3‐12 .     

Fatigue crack growth behaviour of gas tungsten arc,electron beam and laser beam welded Ti–6Al–4V alloy

The present investigation is aimed to evaluate fatigue crack growth parameters of gas tungsten arc, electron beam and laser beam welded Ti–6Al–4V titanium alloy for assessing the remaining service lives of existing structure by fracture mechanics approach. Center cracked tensile specimens were tested using a 100 kN servo hydraulic controlled fatigue testing machine under constant amplitude uniaxial tensile load. Crack growth curves were plotted and crack growth parameters (exponent and intercept) were evaluated. Fatigue crack growth behavior of welds was correlated with mechanical properties and microstructural characteristics of welds. Of the three joints, the joint fabricated by laser beam welding exhibited higher fatigue crack growth resistance due to the presence of fine lamellar microstructure in the weld metal.