Evaluation of Some Nonionic Surfactants Derived From Vanillin as Corrosion Inhibitors for Carbon Steel During Drilling Processes

Four eco‐friendly nonionic surfactants based on vanillin were investigated as corrosion inhibitors against carbon steel dissolution during the drilling process in the oil field. The corrosion inhibition efficiencies of the tested compounds were determined using weight loss, electrochemical polarization, and electrochemical impedance techniques. The data obtained show that the nonionic surfactants prevent the corrosion of drilling tools and their inhibition efficiency increased with an increase in their concentration. Tafel curves revealed that the surfactants under study act as mixed inhibitors. The adsorption of the inhibitors on carbon steel surface decreases the double‐layer capacitance. The inhibition efficiencies of the surfactants were influenced by their chemical structure and surface activity.     

Synthesis,Structure Characterization and Biological Activity of Co (II), Cu (II), and Zn (II) Complexes with (Z)‐3‐((3‐hydroxybenzylidene)amino)pyridin‐1‐ium 4‐(dodecan‐4‐yl)benzenesulfonate Surfactant

(Z)‐3‐((3‐hydroxybenzylidene)amino)pyridin‐1‐ium4‐dodecylbenzenesulfonate anionic surfactant and its cobalt, copper and zinc complexes were synthesized (I, I‐Co, I‐Cu and I‐Zn). The chemical structures of it were characterized by elemental analysis, FTIR, ¹H‐NMR, UV–Vis spectroscopy and atomic adsorption. The effects of the chemical structures of the synthesized anionic surfactant and the type of transition metals on the surface activity are presented in this paper. The thermodynamic parameters show that adsorption and micellization processes are spontaneous. The results of biological activity measurements showed that the synthesized compounds have a great efficiency against gram positive (Bacillus subtilis and Staphylococcus aureus), gram‐ negative bacteria (Pseudomonas aeruginosa and Escherichia coli) and fungi (Candida albicans and Aspergillus niger) as well as the sulfate reducing bacteria (Desulfomonas pigra). The complexation of the anionic surfactant with Co²⁺, Cu²⁺ and Zn²⁺ increase the antimicrobial activity values.     

Quantitative object motion prediction by an ART2 and Madaline combined neural network

An ART2 and a Madaline combined neural network is applied to predicting object motions in dynamic environments. The ART2 network extracts a set of coherent patterns of the object motion by its self-organizing and unsupervised learning features. The identified patterns are directed to the Madaline network to generate a quantitative prediction of the future motion states. The method does not require any presumption of the mathematical models, and is applicable to a variety of situations.     

Synthesis and characterization of alumina-coated carbon nanotubes and their application for lead removal

Alumina-coated multi-wall carbon nanotubes were synthesized and characterized by scanning electron microscopy, X-ray diffraction, and FTIR. They were used as an adsorbent for the removal of lead ions from aqueous solutions in two modes, batch and fixed bed. In the batch mode, experiments were carried out to investigate the effect of contact time, agitation speed, adsorbent dosage and solution pH on the removal of lead. The coated nanotubes exhibit better removal ability over uncoated. For fixed-bed columns, thickness of the layer and flow rate were investigated. Increasing the thickness and decreasing the flow rate enhanced the removal of lead. The prepared adsorbent displayed the main advantage of separation convenience when a fixed-bed column was used compared to the batch adsorption treatment.     

Composite Polymers Transducers for Ultrasonic and Biological Applications

Ferrite polymer transducer and copolyesters are being used for ultrasonic generation to be used in technology and in biological applications like orthodontic treatment. The objectives of this study were to introduce a new piezoelectric composite polymers and to evaluate and compare their electric and mechanical properties with the widely used other materials. The resonance and antiresonance frequencies were measured for the materials in the radial mode. It is noticed that the resonance frequency decreased with increasing CoZn ferrite concentrations in polymers. The electromechanical coupling factor was determined to be of value 0.8 which is the highest value of the piezoelectric materials. It is very difficult to produce ceramic transducers in large sizes because they are fragile, thus the composite transducer could be an alternative. The ultrasonic wave velocity of the composite polymer is higher than that of other polymers and piezoelectric ceramics making them more attractive for many applications than ceramics. The Young's modulus of the composite polymer increased with increasing ferrite concentrations.     

Dynamic behaviour of radio channels due to trans-horizon propagation mechanisms

To study the propagation mechanisms of trans-horizon radio links, the authors propose an event-based approach. Data from one year captured on a trans-horizon link of 156 km are divided into different groups according to the signal amplitude signature of the chart recordings. The propagation mechanisms for each group are investigated using the cross-correlation between received signal amplitudes along the same path. These amplitudes are obtained using two different transmitter antenna heights.<>     

Impact on a model head-helmet system

A numerical finite-element and a corresponding experimental investigation was conducted to study wave transients in an axisymmetric model head-helmet system induced by short-duration impact loading. Two physical systems were examined: (1) a four-component model consisting of a water-filled aluminum spherical shell nesting inside a two-layer hemispherical shell composed of Styrofoam and aluminum and (2) an actual helmet shell filled with an expanding polyurethane foam containing a cadaver head. The response of two other head-helmet systems subjected to sine-squared pulse loadings were also obtained numerically utilizing measured mechanical properties of the constituents.In general, highly satisfactory agreement was found to exist between predicted and experimentally determined strain histories, deviations occurring whenever discrepancies existed between actual and simulated geometry and material properties. Nearly identical levels of strain were measured for the two physical systems tested when loaded by virtually the same impulse in spite of the difference in their characteristics. However, the presence of a frangible covering was found to drastically reduce the pressure levels transmitted to the interior fluid modeling the brain.     

Mapping 3-D IIR digital filter onto systolic arrays

We present here an efficient systolic implementation for 3-D IIR digital filters. The systolic implementation is obtained by using an algebraic mapping technique. This new mapping technique gives us the choice to mix pipelined variables and broadcast variables. We also determine, through the mapping method, the buffer sizes, the direction of variables propagations and the data feeding and extracting points. The resultant systolic array implementation is a modular structure composed of 2-D filter modules connected by simple buffers. This new systolic implementation is regular, modular and amenable to VLSI Implementation.     

Design data for externally pressurised spherical gas bearings

Radial and thrust loading characteristics are given for both single row entry and double row entry bearings. The design data presented gives a basis for comparison of the two bearing configurations. The paper shows that the double entry configuration reduces the negative stiffness regions which occur in single entry bearings. Finally a procedure is given to enable the designer to select a bearing to meet his particular requirements.     

Design of digital filters for advanced telecommunications ASIC'susing a special-purpose silicon compiler

Complex DSP (digital signal processor) ASICs (application-specific integrated circuits) typically feature high-quality filters implemented as dedicated blocks. FIDYS (filter 1di synthesis system) is a new VLSI recursive filter compiler, specifically designed to meet those needs. It is fully integrated from behavioral frequency template specifications down to layout. It comprises a specific approximation and synthesis procedure, the generation of a systolic architecture with parameterized pipelining based on dedicated bit-serial operators, and final generation of a densely packed layout based on a minimal dedicated set of 1-μm CMOS basic cells. A lossless discrete integrator ladder filter structure is used. It features an outstanding low sensitivity and a high degree of modularity and regularity that directly result in streamlined hardware and an efficient placement with minimal routing overhead. Examples of representative applications for telecommunications circuits are presented