Effect of crude oil ageing on low salinity and low salinity surfactant flooding

Injection of brine with lower salinity than the connate brine has proven to give a moderate increase in oil recovery in sandstones. Recent research has shown that this process will significantly benefit from introducing surfactant optimised for low salinity environment.The mechanisms underlying increased recovery by low salinity brine injection are not yet fully understood. However, research to date suggests that they are related to complex crude oil/brine/rock interactions. With this in mind, the present paper investigates primarily how the extent of oil recovery from Berea sandstones subjected to long term exposure of crude oil is influenced by (1) low salinity water injection and (2) combined process low salinity water injection with surfactant flooding.Core displacement tests were conducted on four Berea cores (30 cm), two in a natural state and two that had been subject to extensive crude oil ageing at high temperature. Results obtained from different flooding steps are discussed in terms of oil recovery and effluent properties including turbidity, pH- and ion analysis (Na⁺, Mg²⁺, Ca²⁺). The results effectively illustrate that oil recoveries from the aged cores are higher during both low salinity water injection and low salinity water injection combined with surfactant flooding. An assessment of how tertiary oil recovery in aged and unaged cores varies with surfactant concentration is also presented.Effluent ion analysis from low salinity water floods showed that Mg²⁺ ions were strongly retained in the aged core while Ca²⁺ ions were being produced from both aged and unaged cores. The latter was attributed mainly to calcite dissolution. Results obtained from pressure profiles, effluent ion analysis and turbidity tests suggest higher production and elution of fine particles from the unaged core.     

Determination of metals in fish livers by flameless atomic absorption spectroscopy

The samples are digested in nitric acid and evaporated to near dryness. Hydrogen peroxide is then added for complete oxidation of fat residues. Determination of metals is performed by flameless AAS with graphite furnace and results evaluated by the method of standard addition. The method is suitable for the determination of some non-volatile metals in fish livers in which the amount of available sample is limited; Pb, Cd, Cu and Zn have been determined in such samples.     

Identification of material hardening parameters by three-point bending of metal sheets

Calibration of hardening and partly viscoplastic parameters of the previously published material model was the primary concern of this paper. The method used for identification of the material hardening parameters for metals, the three-point cyclic bending of sheets, constitutes a basis for this work. Plastic hardening parameters were determined by comparing load–displacement curves from FE simulations with those from the tests. Since viscoplasticity is assumed, stress–strain curves from uniaxial tension tests at selected strain rates for strain-rate sensitive materials were employed to calibrate corresponding viscoplastic parameters. The optimization problems are solved by means of a commercial optimization code, LS-OPT, using a response surface methodology. The objective is to minimize (by the least-squares method) the sum of the differences between measured and simulated loads. The material parameters were identified for two high-strength steel alloys (ZSte340 and DP600, strain-rate sensitive materials), and one aluminium alloy (AA5182).     

Optical temperature sensing based on the Goos-Hänchen effect

The possibility of constructing an optical sensor for temperature monitoring based on the Goos-H?nchen (GH) effect is explored using a theoretical model. This model considers the lateral shift of the incident beam upon reflection from a metal-dielectric interface, with the shift becoming a function of temperature due mainly to the temperature dependence of the optical properties of the metal. It is found that such a sensor can be most effective by using long wavelength p-polarized incident light at almost grazing incidence onto the metal, where significant variation of negative GH shifts can be observed as a function of the temperature.     

Surface strain measurements of fingertip skin under shearing

The temporal evolution of surface strain, resulting from a combination of normal and tangential loading forces on the fingerpad, was calculated from high-resolution images. A customized robotic device loaded the fingertip with varying normal force, tangential direction and tangential speed. We observed strain waves that propagated from the periphery to the centre of the contact area. Consequently, different regions of the contact area were subject to varying degrees of compression, stretch and shear. The spatial distribution of both the strains and the strain energy densities depended on the stimulus direction. Additionally, the strains varied with the normal force level and were substantial, e.g. peak strains of 50% with a normal force of 5 N, i.e. at force levels well within the range of common dexterous manipulation tasks. While these observations were consistent with some theoretical predictions from contact mechanics, we also observed substantial deviations as expected given the complex geometry and mechanics of fingertips. Specifically, from in-depth analyses, we conclude that some of these deviations depend on local fingerprint patterns. Our data provide useful information for models of tactile afferent responses and background for the design of novel haptic interfaces.     

Low frequency dielectric spectroscopy of bitumen binders as an indicator of adhesion potential to quartz aggregates using Portland cement

The purpose of this investigation was to interpret the bitumen-aggregate adhesion based on the dielectric spectroscopic response of individual material components utilizing their dielectric constants, refractive indices and average tangent of the dielectric loss angle (average loss tangent). Dielectric spectroscopy of bitumen binders at room temperature was performed in the frequency range of 0.01–1000 Hz. Dielectric spectroscopy is an experimental method for characterizing the dielectric permittivity of a material as a function of frequency. Adhesion data has been determined using the Rolling bottle method. The results show that the magnitude of the average tangent of the dielectric loss angle (average loss tangent) depends on bitumen type. The average loss tangent in the frequency range 0.01–1 Hz is introduced as a potential indicator for predicting polarizability and, thereby, adhesion potential of bitumen binders to quartz aggregates when using Portland cement. In order to obtain acceptable adhesion of 70/100 penetration grade bitumen binders and quartz aggregates when using Portland cement, it is suggested that the binder have an average tan δ > 0.035 in the frequency range 0.01–1 Hz.     

Spectral enhancement of SPOT imagery data to assess marine pollution near Port Said,Egypt

Satellite image data were used to detect, monitor and map different pollutants at five study sites along the El-Gamil beach, including El-Debba, El-Manasra, El-Fardous and El-Gamil inlets and the El-Gamil airport. The images were rectified and analysed by ERDAS IMAGINE 8.7. Image processing techniques were applied using ENVI 4.2 to analyse the SPOT image data (10 m resolution) for 2006. Image enhancement, principal component analysis (PCA), band ratios and supervised/unsupervised classifications were applied. Surface water samples were collected during the winter of 2005 and the summer of 2006. Water contamination was found to be higher in the summer than in the winter. SPOT image data from the summer, therefore, was selected to verify the results of metal analysis. Different pollutants detected along the El Manasra and El Debba sites are associated with industrial development, and discharge from natural gas companies and electric power generating stations. Significant water pollution is not unique to this region of the Mediterranean Sea, but is increasingly common at coastal locations throughout the globe. To protect both the marine environment and commercial interests that depend on clean water and beaches (e.g. beach resorts), effective wastewater management practices must be designed, implemented and maintained, along with reasonable development policies. Remote sensing may be an important tool for monitoring the effectiveness of any pollution mitigation strategies.     

Process principle for the production of sintered dynamic component-inherent data storage

This paper presents a method for the magnetic data storage on the surface of gentelligent components. One key issue is the possibility to store customers?? data on components dynamically and to read it out later on. The data storage is carried out magnetically and is demonstrated on a high-speed milling head. As such components are mostly made of light materials without magnetic properties; areas for the data storage on the surface must first be defined. Sintered components made of Mg and of hard magnetic particles have the potential to meet these requirements.     

A neural network approach to fluid quantity measurement in dynamic environments

Sloshing causes liquid to fluctuate, making accurate level readings difficult to obtain. In this paper, a measurement system has been described that can accurately determine fluid quantity in the presence of slosh. The measurement system uses a single-tube capacitive sensor to obtain instantaneous level of the fluid surface. A neural network based classification technique has been applied to predict the actual quantity of the fluid under sloshing conditions. Effects of temperature variations and contamination on the capacitive sensor have been discussed and it is proposed that these effects can also be eliminated with the proposed neural network based classification system. To examine the performance of the classification system, many field trials were carried out on a running vehicle at various tank volume levels that range from 5 L to 50 L. The paper also investigates the effectiveness of signal enhancement on the neural network based signal classification system. Signal enhancement is performed using selected signal smoothing functions such Moving Mean, Moving Median, and Wavelet filters. Results obtained from the investigation are compared with traditionally used statistical averaging methods, and it proved that the neural network based measurement system can produce highly accurate fluid quantity measurements in a dynamic environment. The approach demonstrated herein will enable a wide range of fluid quantity measurement applications in the fields of automotive, naval and aviation industries to produce accurate fluid level readings.