Infrared spectroscopic studies on the interactions of pour point depressants with asphaltene, resin and wax fractions of Bombay high crude

The mutual interactions of asphaltene, resin and wax fractions of Bombay high crude were studied using infrared spectroscopy. The results show that the resin exists as an associated moiety with intermolecular hydrogen bonds, while asphaltene has intramolecular hydrogen bonded systems. Wax is a hydrocarbon system with aromatic and aliphatic groups without any heteroatomic groups. Pour point depressants (PPDs) were found to modify the orientation of the aliphatic portion of the crude fractions and did not interact with the polar groups present in these fractions.     

Hydrophobic properties of TMOS/TMES-based silica aerogels

The hydrophobic properties of tetramethoxysilane (TMOS)-based silica aerogels by incorporating trimethylethoxysilane (TMES) as a synthesis component, are described. The molar ratio of TMES/TMOS (M) was varied from 0 to 4.0 by keeping the TMOS, methanol (MeOH), water (H₂O) and ammonium hydroxide (NH₄OH), molar ratio constant at 1:14:4:3.7×10⁻³. The hydrophobic properties of the aerogels were studied using contact angle measurements, infrared spectroscopy and thermal analysis. The contact angle, θ increased from 100 to 140° for M=0.5 to 4. While the volume shrinkage of the aerogels increased whereas the bulk density decreased with increased M values. The hydrophobic aerogels are thermally stable up to a temperature of 300°C and above this temperature the aerogels become hydrophilic.     

Torsional wave motion of a finite inhomogeneous piezoelectric cylindrical shell

Torsional oscillations of a finite right circular eylindrical shell of inhomogeneous piezoelectric material of (622) crystal class under a time dependent electric potential on the boundary is investigated. The inhomogeneity is restricted to the variations of density and other physical constants of the medium as a certain power of the radial distance. Under certain conditions, the amplitudes of torsional oscillations are found to be high for small values of the inner radius of the shell.     

Stability of partially supported square plates using high precision triangular finite elements

The stability of square plates with partial supports under uniaxial or biaxial uniformly distributed compressive loads is studied using high precision triangular finite elements. Stability parameters are evaluated for both partially simply supported and partially clamped plates for various values of support ratios: limiting values of the support ratios being either fully simply supported/clamped or point supported at the corners/mid-points of the edges.     

Monohydroxylation of unsaturated oils: I. Sulfation-hydrolysis and sultone-formation

Hydroxy unsaturated glycerides were sought from safflower and linseed oils by partial sulfation with sulfuric acid, followed by hydrolysis of sulfate to hydroxy groups. Sulfation of oleicrich oils or their fatty acids and subsequent hydrolysis (effected conveniently with acidified barium chloride) yielded hydroxy products corresponding to 50–70% of the monoene content. Sulfation of a mixture of methyl oleate and linoleate with 78% w/w of sulfuric acid was directed mainly at the oleate component. Safflower oil was partially sulfated without side reactions using 78% or 79% w/w of sulfuric acid, the hydrolyzed products showing hydroxyl value (HV) of about 35 for a loss of 13 units of iodine value (IV). Use of more concentrated sulfuric acid, and subsequent hydrolysis, led to sulfur-containing products which include sultones. Treatment of atrans,trans, but not of acis,trans conjugated diene with sulfuric acid led to sultone formation. It is postulated that when linoleate is sulfated with strong acids, acidisomerization to atrans,trans conjugated diene occurs, probably followed by 1,4-addition of -OH and -SO₃H and quick dehydration of these moieties to give a 1,4-sultone. Linseed oil was apparently sulfated without side reactions using 80% w/w sulfuric acid at 0–5 C and then hydrolyzed to a product of HV 77 and IV 159.     

Effect of aluminium and copper acetylacetonate on physico-chemical properties of tetraethoxysilane based silica aerogels

Silica aerogel granules have been synthesized by doping aluminium acetylacetonate (Al(acac)₃) and Copper acetylacetonate (Cu(acac)₂), in the sol of tetraethoxysilane followed by ambient pressure drying process. The well established silica network provides effective confinement for metal particles which resists the collapse of silica network during ambient pressure drying of wet gel. In this paper, the effect of Al(acac)₃ and Cu(acac)₂ on physico-chemical properties of the aerogels have been studied by varying the concentration of both from 0.0005 to 0.05 M. The chemical composition, hydrophobicity and elemental analysis of Al(acac)₃ and Cu(acac)₂ doped silica aerogels were studied by using X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, contact angle measurement, X-ray diffraction, atomic absorption spectroscopy. The morphological study was carried by using transmission electron microscopy and surface area and pore diameter was measured by BET analysis. The thermal stability of hydrophobic nature was analyzed by simultaneous thermogravimetry and differential scanning calorimetry. The Al(acac)₃ added silica aerogels are found to be superhydrophobic, low dense, high surface area and optically transparent as compared with Cu(acac)₂ doped silica aerogels.     

Novel inexpensive transition metal phosphide catalysts for upgrading of pyrolysis oil via hydrodeoxygenation

Supported molybdenum/molybdenum‐phosphides as inexpensive catalysts for bio‐oil hydrodeoxygenation (HDO) were in‐house prepared using different support materials, i.e., Al₂O₃, activated carbon (AC), MgAl₂O₄, and Mg₆Al₂(CO₃)(OH)₁₆. The HDO activity of these catalysts were investigated using a 100 mL bench‐scale reactor operating at 300°C with an initial hydrogen pressure of 50 bar for 3 h with a pyrolysis oil (PO). The catalytic efficiencies for bio‐oil HDO for the catalysts were compared with the expensive but commercially available Ru/C catalyst. Addition of small amount of P to the Mo catalysts supported on either AC and Al₂O₃ led to increased degree of deoxygenation (DOD) and oil yield compared with those without P. MoP supported on AC (MoP/AC) demonstrated bio‐oil HDO activity comparable to the Ru/C catalyst. Furthermore, three AC‐supported metal phosphides for PO HDO were compared under the same conditions, and they were found to follow the order of NiP/AC > CoP/AC > MoP/AC. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3664–3672, 2016     

Structure and Properties of Explosive Clad HSLA Steel with Titanium

The present work pertains to the study of microstructure and mechanical properties of explosively clad high strength low alloy steel with commercially pure titanium. The clad interface was characterized by metallography, hardness, shear bond strength and bend tests. The present study revealed that the clad interface was wavy in nature. Shear bond strength of clad interface was in between substrate and clad material. The three point bend tests were conducted on clad joint in such a way that cladding layer was subjected to tension and compression which have not shown any cracks at the interface. The mechanism and reasons for the observed behaviour have been discussed correlating microstructure, mechanical properties, fracture features and diffusion across the interface.     

High temperature polymer electrolyte membrane fuel cell performance of PtxCoy/C cathodes

Carbon-supported Pt-Co alloy nanoparticles of varying Pt:Co atomic ratios of 1:1, 2:1, 3:1 and 4:1 are prepared, characterized and tested in high temperature PEM fuel cell intend to reduce the Pt loading. These electrocatalysts are prepared by borohydride reduction method in the presence of citric acid as stabilizing agent. Face-centered cubic structure of Pt is evident from XRD. The positive shift of Pt diffraction peaks with increasing cobalt content in the Pt_xCo_y/C catalysts indicated the solubility of Co in Pt lattice. The average crystallite size is found to be 6 nm in all the prepared catalysts. The electrochemical active surface area (EAS) of the catalysts from CO-stripping voltammetry is calculated to be 65.2, 51.4, 47.7, 41.5 and 38.3 m² g⁻¹ Pt for Pt/C, Pt-Co(4:1)/C, Pt-Co(3:1)/C, Pt-Co(2:1)/C and Pt-Co(1:1)/C, respectively. These catalysts are used as cathode in the fabrication of polybenzimidazole-based membrane electrode assembly (MEA) and the polarization curves are recorded at 160 and 180 °C. The results indicate the good performance of Pt-Co alloys than that of Pt under the PEM fuel cell conditions. Among the investigated electrocatalysts, Pt-Co(1:1)/C and Pt-Co(2:1)/C exhibited good fuel cell performance. Durability tests also indicated the good stability of Pt-Co(1:1)/C and Pt-Co(2:1)/C compared to Pt/C.