Crude Source Research Articles

A MEG study of sleep

A 64-channel, whole cortex magnetoencephalographic system was employed to obtain sleep data from three healthy subjects. Based upon visual inspection of the signals and the corresponding power spectra, we were able to discern a number of features characterizing the evolution of sleep. These included: (1) the transition from records dominated by the alpha rhythm to records in which alpha is attenuated and slower waves increase; (2) the appearance of sleep spindles, particularly in the parietal channels; and, perhaps most interesting, (3) a slow wave phase whose multichannel spectral signature is a broad rounded maximum in the frequency region around 0.5 Hz. Topographical features of the sleep record were also studied. In two of our subjects, rough lateral symmetry was apparent. As their sleep deepened, the distribution of signal power over the head changed such that the maximum moved in the forward and lateral directions, with parietal and temporal signals strengthening relative to the occipital. The records of the third subject showed a tendency toward right dominance, while topographic changes with sleep depth were minimal. Only one of the subjects was able to sustain the deep, slow-wave stage. Here, characteristic multi-detector outbursts appeared, lasting between 150 and 500 ms. During these intervals, widespread topographic patterns were sustained over the head (often with striking dipolar or quadrupolar forms), while crude source modeling yielded two persisting dipoles, laterally paired. Thus, these outbursts seem to represent large-scale, quasi-static configurations of brain activity perhaps related to the K-complexes, which occur earlier in sleep. Finally, we compare our results with those of previous investigators, including work on human electroencephalographic data and research reported by Steriade et al. from animal studies.

Evaluation of the properties and storage stability of EVA polymer modified asphalt

Polymers are being increasingly used for modification of Asphalt to enhance highway pavement performance. This paper describes the polymer modification of two penetration grade Asphalt with ethylene vinyl acetate (EVA). Two base asphalt from two crude oil sources (Baiji paraffinic asphalt & Qaiyarah aromatic asphalt) were mixed with ethylene vinyl acetate (EVA) at different polymer content. The physical properties including softening point, penetration at 25°C, and ductility of the basic asphalt and ethylene vinyl acetate modified asphalt were studied. It has been observed that the softening point has increased on the other hand, the penetration and ductility values has decreased according to the test results. The effect of storage time on uniformity at higher temperature was studied by storage stability test .

Nitrogen compound distribution in middle distillate fuels derived from petroleum, oil shale, and tar sand sources

Nitrogen compounds present in crude sources constitute serious problems both for producers and consumers. For producers, these compounds are responsible for poisoning catalysts during the refining processes. For consumers, these compounds are responsible for the degradation observed in fuels during storage and handling. The quality of petroleum, as measured by °API gravity, continues to decrease in quality. This, coupled with the inevitable use of other crude sources, if used in quantity will further decrease the stability of middle distillate fuels. In this article we present our method for the separation and quantitation of the slate of nitrogen compounds present in middle distillate fuels derived from petroleum, oil shale and tar sand sources. Results from our laboratory indicate that of all of the nitrogen compounds present in middle distillate fuels, the indole type structure is the most deleterious.

CHARACTERISATION OF PARAFFIN WAXES BY DSC AND HIGH TEMPERATURE GC

ABSTRACT Paraffin waxes of different crude oil sources were characterised using Differential Scanning Calorimetry, and High Temperature Capillary GC techniques. The carbon number distribution of the waxes were determined by calibrating the GC with standard n-paraffins blend. The δHs−s transition obtained in DSC. thermogram of the waxes were correlated with its normal paraffin content. This correlation was further validated by obtaining n-paraffins content through High Temperature GC technique.

Rapid screening of textile dyes employed as affinity ligands to purify enzymes from yeast.

A rapid method for screening potential dye ligands for use in affinity chromatography is described. Textile dyes were non-covalently coupled to a cross-linked polysaccharide Sepharose(R) matrix. Yeast alcohol dehydrogenase (ADH) was used as the model protein for evaluating the screening system. A homogenate from baker's yeast was used as the crude source of enzyme. Batchwise adsorption and elution were used to evaluate the individual dyes. The influence of pH and ionic strength in the binding and elution steps was evaluated. Batch isotherms were used to evaluate parameter characteristics. Experimental data obtained were fitted to Langmuir isotherms to determine the maximum binding capacity and the dissociation constant for each dye evaluated in this study. A dynamic binding capacity of 107.6 units of ADH/g of resin was determined for Procion Turquoise MXG dye by frontal analysis. Specific elution with NAD+ and non-specific elution with 50 mM Tris/HCl buffer, pH 8.5, were tested when Procion Turquoise MXG was used, giving purification factors of 53.5 and 4.4 respectively. This screening technique is inexpensive and can be performed in a few hours. It was possible to predict the performance of different reactive dyes in this way, and the influence of pH and salt on the binding behaviour was demonstrated.

Affinity purification of mouse monoclonal IgE using a protein A mimetic ligand (TG19318) immobilized on solid supports.

A synthetic ligand (TG19318), deduced from the screening of a combinatorial peptide library, has been previously characterized by our group for its applicability in affinity chromatography for polyclonal and monoclonal IgG purification from crude sources. In this study we have extended the characterization of its recognition properties for other immunoglobulin classes, evaluating its ability to purify mouse monoclonal IgE from ascitic fluid. TG19318 affinity columns proved useful for a very convenient one-step purification of IgE directly from crude ascites, by loading the samples on the columns equilibrated with 50 mM sodium phosphate at pH 7 and eluting and adsorbed IgE by a buffer change to 0.1 M acetic acid. Antibody purity after affinity purification was very high and no albumin traces were detected, as determined by SDS-PAGE analysis. Antibody activity was fully recovered after purification, as determined by immunoassays on antigen-coated plates, and up to 5 mg of IgEs could be purified on a 1 ml column in a single run.

Effect of fibre-rich diets on the backfat skatole content of entire male pigs

The objective was to determine the effect of feeding diets differing in fibre content and source on backfat skatole content and boar taint score of entire male pigs. Sixty entire male pigs (Piétrain×Seghers hybrid cross) were assigned to four dietary treatments and fed ad libitum, in two phases (grower and fattening), one of the following diets: control, one with 15% sugar beet pulp, one with 30% wheat bran and one with 15% soybean hulls. The diets were isocaloric and isonitrogeneous, but differed in crude fibre content and fibre source. Mean crude fibre contents were 5.2, 7.7, 6.2 and 9.9%, respectively. Animal performance, carcass quality, backfat skatole and indole contents and boar taint scores were not influenced by diet. However, the wheat bran diet group gave a numerically ( P=0.219) higher backfat skatole content than the sugar beet pulp diet group (126±182 vs 37±54 ng/g fat; mean±S.D.). Under the experimental conditions, there was no higher risk for skatole formation or boar taint occurrence by feeding fibre-rich diets to entire male pigs, compared with a conventional diet.

Affinity purification of immunoglobulin M using a novel synthetic ligand

While monoclonal antibodies of the G class can be conveniently purified by affinity chromatography using immobilized protein A or G, even on a large scale, scaling up IgM purification still presents several problems, since specific and cost-effective ligands for IgM are not available. A synthetic peptide (TG19318), deduced from the screening of a combinatorial peptide library, was characterized previously by our group for its binding properties for immunoglobulins of the G class and its applicability as a synthetic ligand for polyclonal and monoclonal IgG purification, from sera or cell culture supernatants. In this study, we have examined the ligand recognition properties for IgM, immobilizing the synthetic peptide on different affinity supports and examining its ability to purify IgMs from serum, ascitic fluid and cell culture supernatants. TG19318 affinity columns proved useful for a very convenient one-step purification of monoclonal IgMs directly from crude sources, loading the samples on the columns equilibrated with saline buffers at pH values ranging from 5 to 7, and eluting adsorbed IgM by a buffer change to 0.1 M acetic acid or 0.05–0.1 M sodium bicarbonate, pH 9.0. Antibody purity after affinity purification was very high, close to 85–95%, as determined by densitometric scanning of sodium dodecyl sulfate–polyacrylamide gels of purified fractions, and by gel permeation analysis. Antibody activity was fully recovered after purification, as determined by immunoassays. Column capacity was related to the type of support used for ligand immobilization, and ranged from 2 to 8 mg of IgM/ml of support.

Dynamic Shear Rheological Properties of Polymer-Modified Asphalt Binders

Rheological characteristics were measured using DSR (Dynamic Shear Rheometry) for two asphalts (A and B, conventional AC-20 viscosity grades) from different crude sources modified with 5% SBR, 5.5% LDPE, 5% SB, and a crumb rubber (5%)/SBS (2%) mixture. Mastercurves were constructed from DSR frequency sweeps at temperatures ranging from -20 to 80°C. The mastercurves were constructed using the method of reduced variables, similar to the WLF equation, and described all binders well except for the A-LDPE binder. Polymer network formation is suggested in the B-SB binders based on the tendency of the tan δ mastercurve to exhibit a local minimum and the lack of observable phase separated polymer domains within the resolution of the fluorescence microscope. The morphology of the SBR polymer in the asphalt was observed to be dependent on the specific asphalt source. Initiation of polymer network formation is postulated for B-SBR based on the behavior of tan δ and the asphalt swollen phase separated polymer domains as observed by fluorescence reflection microscopy. For B-LDPE, A-CR + SBS, and B-CR + SBS the response of tan δ suggests networking but is postulated to be a contribution of the clearly observable phase separated polymer domains. The overall response of B-LDPE and the CR + SBS binders are a sum of the contributions of each phase with the polymer acting more as a filler, dominating the rheological response at intermediate frequencies.

PHYSICO-CHEMICAL AND COMPOSITIONAL ASPECTS OF BITUMEN BEARING CRUDES AND THEIR INSTRUMENTAL CHARACTERISATION

In India the production of bitumen is primarily based on middle-east crude oils which normally have a right balance of bitumen constituents (i.e. asphaltenes and maltenes). In general, bitumens obtained from such crude oil sources have a good balance of rheological and physico-chemical properties at both low and high temperatures. Bitumen is a complex mixture consisting of compounds ranging from non-polar aliphatic and naphthenic hydrocarbons to highly polar aromatic molecules containing heteroatoms such as oxygen, nitrogen, and sulfur; and, several attempts have been reported to fractionate and characterise bitumens into broadly defined compound groups. The separation method adopted in the present study is based on the polarity of the constituent compounds comprising the bitumen. The separated groups of compounds which progressively increase in their polarities are saturates, aromatics, resins and asphaltenes. In the present study three important (middle-east) bitumen bearing short residues have been selected and their detailed physico-chemical as well elemental compositions have been reported. Each short residue has been characterised by NMR and FT-IR spectroscopy methods and the information obtained from these analyses have been used to estimate several average structural parameters. Ultimate compositions have been determined for deducing the average molecular formulae.

In vitro hydrolysis of phytate in canola meal with purified and crude sources of phytase

Pre-treatment conditions required to hydrolyze phytate in canola meal with crude and purified phytases were investigated. Phytase (10,000, 100,000, 340,000 U/kg Natuphos®) and the same phytase (10,000, 100,000 U/kg) that had been purified by gel filtration were added to canola meal without pH adjustment (pH 5.8, 2:1 H 2O: meal). Phytate hydrolysis was incomplete after 30 and 60 min (50°C) indicating that a portion of the phytate was resistant to hydrolysis. Purified and crude phytases (10,000 U/kg) were used to hydrolyze canola meal at pH 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0 and 5.8. Phytase was more effective between pH 3 and 5. Crude phytase was significantly more effective ( P<0.0001) than purified enzyme, suggesting that non phytase enzymes facilitated the action of phytase. The levels of lower inositol phosphates in response to incubation pH were similar to phytate, suggesting that they too are susceptible to the formation of complexes which prevent hydrolysis. Complete hydrolysis with crude phytase (pH 5.0, 5000 U/kg, 50°C, 2:1 H 2O: meal) in 250 g batches was accomplished within 23 h. In conclusion, a portion of the phytate in canola meal is resistant to hydrolysis by phytase. Therefore, meal pretreatment, which includes pH modification, temperature and moisture control, and the addition of phytase and other enzymes, is required for the effective hydrolysis of phytate.

Composition and toxicity of petroleum products and their additives.

1. All petroleum based products are highly complex chemical mixtures. Although almost exclusively composed of hydrocarbons, the composition varies with the crude oil source. 2. Their toxicity for man is generally low but there are exceptions. Although irritancy and sensitization to specific ingredients may be demonstrated in animals, animal experiments are not a reliable indicator of sensitization potential in man. 3. Both product complexity and commercial considerations can make acceptable and meaningful compositional disclosures difficult. A nomenclature system exists which solves these problems. 4. Frame formulations would have some value to poisons centres dealing with petroleum product enquiries. 5. As legislation for the European Union is developed, the balance must be reached between disclosure of the (often confidential) precise chemical composition of products and a practical and useful composition for the guidance of users and medical personnel. This is a key issue with some petroleum products, mainly due to the additives used in them. 6. For several reasons, such as climatic conditions or logistics of supply, the various components, including additives, used in a branded product may vary because the final product composition is determined not by chemistry but by performance in service. 7. Lubricants may contain between 10 and 20% of additives; fuels contain additives only at parts per million levels. However, for both fuels and lubricants, toxicity from additives is rarely a matter of concern.

Influence of maturity on carbazole and benzocarbazole distributions in crude oils and source rocks from the Sonda de Campeche, Gulf of Mexico

Carbazole geochemistry has been studied for a petroleum system in which vertical migration is prominent and where reservoirs are locally sourced. An essentially uniform organofacies of organicrich Tithonian source rocks from the Sonda de Campeche (Gulf of Mexico), covering a well defined maturity sequence (0.36–1.29% R r) and associated crude oils (0.49–0.92% R c) from Palaeocene reservoirs formed the sampling base. Comparison of the distribution of alkylcarbazoles and benzocarbazoles in rock bitumens and oils revealed that fractionation due to primary expulsion had no effect on the distribution of shielded/exposed carbazoles within crude oils. Perhaps more importantly, the benzocarbazole ratio in both rock extracts and crude oils increased with maturity, indicating that this parameter cannot be directly used as a migration indicator in petroleum systems where vertical migration through faults and fissures represents the main avenues of oil migration.

One step purification of chymosin by mixed mode chromatography

Mixed mode Sepharose and Perloza bead cellulose matrices were prepared using various chemistries. These matrices contained hydrophobic (aliphatic and/or aromatic) and ionic (carboxylate or alkylamine) groups. Hydrophobic amine ligands were attached to epichlorohydrin activated Sepharose (mixed mode amine matrices). Hexylamine, aminophenylpropanediol and phenylethylamine were the preferred ligands, on the basis of cost and performance. Other mixed mode matrices were produced by incomplete attachment (0-80%) of the same amine ligands to carboxylate matrices. The best results were obtained using unmodified or partially ligand-modified aminocaproic acid Sepharose and Perloza. High ligand densities were used, resulting in high capacity. Furthermore, chymosin was adsorbed at high and low ionic strengths, which reduced sample preparation requirements. Chymosin, essentially homogeneous by electrophoresis, was recovered by a small pH change. The methods described were simple, efficient, inexpensive and provided very good resolution of chymosin from a crude recombinant source. The carboxylate matrices had the best combination of capacity and regeneration properties. The performance of Sepharose and Perloza carboxylate matrices was similar, but higher capacities were found for the latter. Because it is cheaper and can be used at higher flow rates, Perloza should be better suited to large scale application. High capacity chymosin adsorption was found with carboxymethyl ion exchange matrices, but low ionic strength was essential for adsorption and the purity was inferior to that of the mixed mode matrices.

Reactivity of Asphalt Supercritical Fractions

The reactivities of six supercritical fractions of asphalt SHRP AAF-1 were investigated in the context of their chemical composition. The supercritical fractions were obtained using pentane as the solvent. Each fraction was aged in a pressure oxygen vessel (POV) under seven conditions of temperature and pressure. As with whole asphalts, there is an initial rapid oxidation that slows to a constant rate. The oxidation rates for the constant rate region were measured at each of the conditions to determine the kinetic parameters of the fractions. Arrhenius plots were then constructed for the fractions to compare their reactivities. Variations in activation energy and reaction order were within experimental error. Results show that reactivity increases with fraction number for the supercritical fractions. The heavier fractions are more reactive not only because they contain more polar aromatics in terms of Corbett analysis fractions but also because the polar aromatics of the heavier fractions are larger in molecular size and are more reactive. Additionally, heavier fractions contain more asphaltenes that are larger in molecular size. Because for light fractions the reaction rates, and as previously shown the hardening rates, are very low and remain constant with oxidation, air blowing of some light fractions would be expected to produce an asphalt with a very low hardening rate. Data explicitly show that for petroleum fractions from the same crude source molecular size distribution is a good indicator of reactivity. This is not necessarily true for petroleum fractions from different crude sources, however.

Additional calcium carbonate into concentrate diet for sheep fed ensiled king grass as a based-diet

In order to ascertain the effect of additional calcium carbonate into concentrate diet, on the performance of sheep fed ensiled king grass as a basal diet, a trial was conducted using 28 growing sheep ( average body weight 17 _+ 1 .4 kg). Based on body weight, the animals were grouped and randomized into four dietary treatments in block randomized design . Dietary treatments were (i) chopped king grass + 400 g of concentrate, (ii) ensiled king grass + 400 g concentrate + 0 % of calcium carbonate, (iii) ensiled king grass + 400 g concentrate + 5 % calcium carbonate and (iv) ensiled king grass + 400 g concentrate + 10 % calcium carbonate . Results showed that offering 5 % of calcium carbonate into concentrate diet increased (P 0 .05) for all groups . No differences in the apparent digestibility of the nutrient components were observed, but crude protein decreased significantly (P < 0 .05) . A significant relationship ( P < 0 .01) was found between nitrogen intake (NI) and nitrogen retention (NR), and the equation was NR = - 0.1848 + 0.3788 NI ( r = 0.9 ) . Based on data found that feeding only ensiled king grass as a single diet could not meet the maintenance requirement of energy and protein, therefore, additional energy and crude protein sources is needed . Keywords : Silage, king grass, growing sheep

Adamantanes from petroleum with zeolites

Experiments with zeolite Beta and zeolite Y demonstrate that adamantane and methyl adamantanes can be isolated very effectively from modern refinery streams by mild hydrocracking over Pt-and Pd-containing large pore zeolites. Yield depends importantly on individual refinery crude source and process configuration. Heavy crudes and refineries with conventional hydrocracking and FCC feed hydrotreater facilities are particularly desirable, and an ideal feed for adamantane isolation in such a situation is the 150–250°C fraction of the hydrocracker (HDC) recycle stream. When Pt-or Pd-containing zeolite Beta was used with such a stream, temperatures of some 250°C and pressures below 3.5 mPa (500 psig) sufficed to remove selectively well over 90% of the non-adamantane hydrocarbon, with little conversion of adamantanes. High selectivity for adamantanes is attributed in large part to size-selective exclusion of these molecules from the pores of zeolite Beta.

A quick method for purifying bile salt-activated lipases

A simple, one step chromatography procedure of general utility for purifying bile salt-activated lipases (BAL; cholesterol esterases) using a cholate affinity column is described. A key feature of the method is the use of a taurocholate concentration gradient in the eluent. The method has been used successfully to purify bovine and porcine BAL from commercial crude sources and BAL from human milk whey.

Extended hopanes beyond C 40 in crude oils and source rock extracts from the Liaohe Basin, N.E. China

A series of 17α(H),21β(H)-hopanes and 17β(H),21α(H)-moretanes up to C 44 has been identified in crude oils and source rock extracts in the Liaohe Basin, N.E. China. This result extends the previously known homologous series reported up to C 40 for 17α(H),21β(H)-hopanes and C 35 for 17β(H),21α(H)-moretanes. These compounds may be viewed as the representatives of a new class of molecules whose natural distribution and biological significance remains to be determined, although the possibility of diagenetic modification of the known hopane precursors cannot be ruled out.

Differential Scanning Calorimetry Study of Asphalt Crystallinity

Eight asphalt samples with grades ranging from AC10 to AC30 from four different sources were examined using NMR, FTIR, and differential scanning calorimetry. The crystallization process of asphalt is very time dependent. Slow heating or annealing before analysis to experimentally realize a near-equilibrium state is necessary to study the system with more thermodynamic rigor. Indeed, the annealing method developed in this work resolves a number of low-temperature transitions characteristic of a given crude and/or refinery source; thus, comparison of thermograms from an unknown source with reference thermograms from documented sources allows one to identify the unknown source. The crystallization process of a selected AC-20 asphalt, ACB, was systematically studied by doping with the following pure crystalline hydrocarbons: octadecene-1, eicosane, and octacosane. The impact of doping on the crystalline fractions in asphalt varies from asphalt to asphalt. The crystalline components in asphalt exhibit distinct endothermic patterns that depend on their chemical structure, the interactions with the amorphous phase, and among themselves. The most significant endothermic effect is produced by cocrystallization of components with similar crystalline chain lengths. For example, the crystalline components of asphalt ACB do not interact with octadecene-1, but do cocrystallize with eicosane and octacosane.