Factors that influence properties of FOG deposits and their formation in sewer collection systems.

Understanding the formation of Fat, Oil, and Grease (FOG) deposits in sewer systems is critical to the sustainability of sewer collection systems since they have been implicated in causing sewerage blockages that leads to sanitary sewer overflows (SSOs). Recently, FOG deposits in sewer systems displayed strong similarities with calcium-based fatty acid salts as a result of a saponification reaction. The objective of this study was to quantify the factors that may affect the formation of FOG deposits and their chemical and rheological properties.

Mechanisms of fat, oil and grease (FOG) deposit formation in sewer lines.

FOG deposits in sewer systems have recently been shown to be metallic salts of fatty acids. However, the fate and transport of FOG deposit reactant constituents and the complex interactions during the FOG deposit formation process are still largely unknown. In this study, batch tests were performed to elucidate the mechanisms of FOG deposit formation that lead to sanitary sewer overflows (SSOs).

Evidence for fat, oil, and grease (FOG) deposit formation mechanisms in sewer lines.

The presence of hardened and insoluble fats, oil, and grease (FOG) deposits in sewer lines is a major cause of line blockages leading to sanitary sewer overflows (SSOs). Despite the central role that FOG deposits play in SSOs, little is known about the mechanisms of FOG deposit formation in sanitary sewers. In this study, FOG deposits were formed under laboratory conditions from the reaction between free fatty acids and calcium chloride.

Characterization of monolayer formation on aluminum-doped zinc oxide thin films.

The optical and electronic properties of aluminum-doped zinc oxide (AZO) thin films on a glass substrate are investigated experimentally and theoretically. Optical studies with coupling in the Kretschmann configuration reveal an angle-dependent plasma frequency in the mid-IR for p-polarized radiation, suggestive of the detection of a Drude plasma frequency. These studies are complemented by oxygen depletion density functional theory studies for the calculation of the charge carrier concentration and plasma frequency for bulk AZO.

Study of the packing density and molecular orientation of bimolecular self-assembled monolayers of aromatic and aliphatic organosilanes on silica.

Bimolecular self-assembled monolayers (SAMs) of aromatic and aliphatic chlorosilanes were self-assembled onto silica, and their characteristics were established by contact angle measurement, near-edge X-ray absorption fine structure spectroscopy, and Fourier transform infrared spectroscopy. Three aromatic constituents (phenyltrichlorosilane, benzyltrichlorosilane, and phenethyltrichlorosilane) were studied in combination with four aliphatic coadsorbates (butyltrichlorosilane, butyldimethylchlorosilane, octadecyltrichlorosilane, and octadecyldimethylchlorosilane). Our results demonstrate that whereas SAMs made of trichlorinated organosilanes are densely packed, SAMs prepared from monochlorinated species are less dense and poorly ordered.

Resonance Raman study of ferric heme adducts of dehaloperoxidase from Amphitrite ornata.

The study of axial ligation by anionic ligands to ferric heme iron by resonance Raman spectroscopy provides a basis for comparison of the intrinsic electron donor ability of the proximal histidine in horse heart myoglobin (HHMb), dehaloperoxidase (DHP), and horseradish peroxidase (HRP). DHP is a dimeric hemoglobin (Hb) originally isolated from the terebellid polychaete Amphitrite ornata. The monomers are structurally related to Mb and yet DHP has a peroxidase function.

Testing bridge-mediated differences in dinuclear valence tautomeric behavior.

Two structurally characterized dinuclear valence tautomers are described. Cobalt ions are bridged by p- and m-phenylene units connected to 2,2'-bipyridines. X-ray crystal structures show that the molecules are in the [(Co(III))(Co(III))] forms at ca.

Infrared detection of a phenylboronic acid terminated alkane thiol monolayer on gold surfaces.

Polarization modulation infrared reflectance absorption spectroscopy (PM-IRRAS) and infrared reflectance absorption spectroscopy (IRRAS) have been used to characterize the formation of a self-assembled monolayer of N-(3-dihydroxyborylphenyl)-11-mercaptoundecanamide) (abbreviated PBA) on a gold surface and the subsequent binding of various sugars to the PBA adlayer through the phenylboronic acid moiety to form a phenylboronate ester. Vibrationally resonant sum frequency generation (VR-SFG) spectroscopy confirmed the ordering of the substituted phenyl groups of the PBA adlayer on the gold surface. Solution FTIR spectra and density functional theory were used to confirm the identity of the observed vibrational modes on the gold surface of PBA with and without bound sugar.

Supramolecular control of valence-tautomeric equilibrium on nanometer-scale gold clusters.

This communication describes the preparation and characterization of a valence tautomer complex covalently attached to gold nanoparticles. Variable-temperature IR spectroscopy is used to determine the equilibrium thermodynamic parameters for the valence tautomerization. These results are compared with a nonsurface combined valence tautomer complex.

Covalent attachment of a nickel nitrilotriacetic acid group to a germanium attenuated total reflectance element.

The surface of a germanium internal reflectance element (IRE) was modified to bind 6X-histidine (his)-tagged biomolecules. The step-by-step surface modification was monitored via single-pass attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FT-IR). Initially an adlayer of 7-octenyltrimethoxysilane (7-OTMS) was formed on the Ge crystal through the surface hydroxyl groups, which were produced via ozonolysis of the Ge surface.

Characterization of single- and double-stranded DNA on gold surfaces.

Single- and double-stranded deoxy ribonucleic acid (DNA) molecules attached to self-assembled monolayers (SAMs) on gold surfaces were characterized by a number of optical and electronic spectroscopic techniques. The DNA-modified gold surfaces were prepared through the self-assembly of 6-mercapto-1-hexanol and 5'-C(6)H(12)SH -modified single-stranded DNA (ssDNA). Upon hybridization of the surface-bound probe ssDNA with its complimentary target, formation of double-stranded DNA (dsDNA) on the gold surface is observed and in a competing process, probe ssDNA is desorbed from the gold surface.

Infrared spectra of H(2)16O, H(2)18O and D(2)O in the liquid phase by single-pass attenuated total internal reflection spectroscopy.

Mid-infrared attenuated total internal reflection (ATR) spectra of H(2)16O, H(2)18O and D(2)16O in the liquid state were obtained and normal coordinate analysis was performed based on the potential energy surface obtained from density functional theory (DFT) calculations. Fits of the spectra to multiple Gaussians showed a consistent fit of three bands for the bending region and five bands for the stretching region for three isotopomers, H(2)16O, H(2)18O and D(2)16O. The results are consistent with previous work and build on earlier studies by the inclusion of three isotopomers and mixtures using the advantage of single-pass ATR to obtain high quality spectra of the water stretching bands.

Efficiency and pattern of UV pulse laser-induced RNA-RNA cross-linking in the ribosome.

Escherichia coli ribosomes were irradiated with a KrF excimer laser (248 nm, 22 ns pulse) with incident pulse energies in the range of 10-40 mJ for a 1 cm2 area, corresponding to fluences of 4.5 to 18 x 10(9) W m(-2), to determine strand breakage yields and the frequency and pattern of RNA-RNA cross- linking in the 16S rRNA. Samples were irradiated in a cuvette with one laser pulse or in a flow cell with an average of 4.

Eigenvector mapping: a method for discerning solvent effects on vibrational spectra.

This paper reports a density functional theory (DFT) analysis of the adenine spectra in a hydrogen-bonding environment. We compare the theoretical vibrational spectra of 26 model systems in which water has been hydrogen bonded to adenine with the experimental frequencies of the solid state infrared spectra (150-1700 cm(-1)) of polycrystalline adenine and the experimental frequencies observed in matrix isolation spectra of adenine [J. Phys.