Micellization and Adsorption Behaviors of New Reactive Polymerizable Surfactants Based on Modified Nonyl Phenol Ethoxylates

The synthesis and characterization of a series of polymerizable surfactants based on alkyl phenol ethoxylate backbone and carboxylic or anhydride chain ends were investigated. Surface activities of these polymerizable surfactants were investigated to correlate their structure and their performances. The new bifunctional surfmers were prepared by reacting polyoxyethylene 4-nonyl-2-propylene-phenol nonionic reactive surfactants with maleic anhydride. The chemical structure of the prepared surfactants was characterized by ¹³C and ¹H NMR analyses. The surface activities of the modified polymerizable surfactants were measured from the adsorption isotherm measurements which were determined from the relationship between the concentrations and surface tension of surfactants in aqueous medium at different temperatures. Critical micelle concentration (CMC) values were determined for water soluble surfactants. It was found that CMC decreases with the incorporation of the anhydride and acid groups in the chemical structure of polyoxyethylene 4-nonyl -2-propylene-phenol nonionic surfactant. surface-active parameters such as area per molecule at the interface (A _min), surface excess concentration (Γ_max) and the effectiveness of surface tension reduction (π_CMC) were measured from the adsorption isotherms of the modified surfactants. Some thermodynamic data for the adsorption process were calculated and discussed. The data indicated that the new surfmers are more reactive than the simple polyoxyethylene 4-nonyl-2-propylene-phenol and more adsorbed at interfaces. We have performed a preliminary experiment to explore the emulsification efficiency of the newly synthesized reactive surfactants in equal volume oil–water emulsions. Different emulsion types and stabilities were obtained.     

Nonclassical features of entangled coherent states

Nonclassical features of entangled coherent states (two-mode superposition coherent states) based on two coherent states shifted in phase by π/2 are discussed. Analysis of Cauchy–Schwartz inequality, two-mode quadrature squeezing, oscillatory and sub-Poissonian photon statistics show that nonclassicality exists for these states. Furthermore, it is also observed that special states have remarkably strong nonclassical properties than the entangled coherent states based on famous even–odd coherent states.     

Parametric studies on drill-string motions

Experimental and numerical investigations are conducted into drill-string motions. The numerical efforts are carried out by using a reduced-order model with attention to stick–slip interactions between a drill string and an outer shell. These efforts are complemented by experimental studies conducted with a unique, laboratory scale model. Qualitative and quantitative changes in the system behavior are studied with respect to the rotation speed and mass imbalance. Comparisons are made between the numerical findings and the corresponding experimental results. In addition, the influence of contact conditions between the drill string and the outer shell on the drill-string dynamics is also examined. The findings of the work suggest that small changes in the system rotation speed can have a significant influence on the nature of drill-string motions and they also provide guidelines for steering the system out of regions of undesirable dynamics and maintaining drill-string motions close to the center of a borehole.     

Zirconia modified by Cs cationic exchange: Physico-chemical and catalytic evidences of basicity enhancement

Zirconia promoted with Cs was prepared by cationic exchange of zirconium hydroxide with Cs, then calcined at 550 °C, and refluxed in ethanol to remove weakly bonded Cs species. The promotion with Cs stabilized the ZrO₂ tetragonal phase and has significantly increased the amount and the strength of the basic sites titrated by microcalorimetry of CO₂ adsorption. XPS gave evidence of an electronic enrichment of Zr and O atoms and an enhanced amount of superficial carbonates over ZrOCs. In vegetable oil transesterification, TOFs higher than those of ZrO₂, MgAl-HDT, and NaOH were achieved over ZrOCs, demonstrating the potential of this novel solid base.     

Enzymatic production of biodiesel from used/waste vegetable oils: Design of a pilot plant

In this work, a proposed pilot plant has been designed to produce 1 ton h^?1 biodiesel (BD) from waste/used vegetable oil using enzymatic approach. Complete material and energy balances were carried out using Excel spreadsheets, and detailed equipment sizing were determined. Immobilized lipase (Novozyme 435) is used as a catalyst in a packed bed bioreactor. The effluent of the reactor is passed though a Liquid–liquid extractor to separate the BD from other components. This is followed by a flash dram and a vacuum distillation column for further purification of the product. In addition, an economic feasibility of this process was assessed. The amount of feed streams of waste oil, methanol and tert-butanol required were found to be 1138, 130 and 7.6 kg h^?1, respectively. The main units in the proposed plant were designed and the economic feasibility of the process was assessed. It was found that the total capital investment required is about US$ 620,000, which will be paid back within four years of operation.     

Petrographic, mechanical and chemical properties of major coarse aggregate resources in Lebanon, eastern Mediterranean

 In a previous study to locate the major coarse aggregate resources currently being exploited in the Lebanon, 20 major operating quarrying sites were located, described and sampled. This paper reports the evaluation of these samples, based on petrographic analysis and mechanical and chemical acceptance tests as well as the results of tests conducted on fresh and hardened concrete samples made with various types of coarse aggregate. In general, the samples were of good quality and suitable for use in concrete although the grading of the aggregates varied widely between quarries and some samples were found to be gap graded. Only the material from Berquayel failed the soundness test. Cherts were identified in some of the samples, leading to the conclusion that alkali-aggregate reactions might occur in these rocks. The results of the concrete tests showed that the measured concrete stiffness was in many cases slightly lower than the anticipated theoretical value. It is hoped that the results of the study will provide valuable assistance to all those involved in the construction industry, including engineers, contractors, ready-mix plant operators and government officials. Received: 21 September 1999 · Accepted: 10 December 1999     

Validation of metamodels in simulation: a new metric

Metamodels are used to provide more efficient predictions than the underlying simulation models do, but at the price of reduced prediction accuracy. Statistics used to quantify this prediction accuracy include the root-mean square error (RMSE), the coefficient of determination R-square, and the average absolute error (AAE). Such statistics depend on the average prediction accuracy over the validation sample; i.e., these metrics are sensitive to the size of the validation sample. This article, therefore, introduces a new metric, called the Model acceptability score (MAS). Preliminary results indicate that MAS is less sensitive to the validation sample size. The article focuses on deterministic simulation, which is used in various engineering disciplines, e.g., electronic engineering.     

Effect of grain crushing and bedding plane inclination on Aqaba sand behavior

This paper reports an experimental investigation into the inherent anisotropy and particle breakage of natural Aqaba sand. The natural sand specimens were subjected to one dimensional compression to induce breakage. The grain size distributions of the specimens were obtained before and after the application of the stresses. Thereafter, the sand shear strength parameters were assessed using direct shear box tests. The results indicate that peak shear strength parameters show little decrease with increasing particle breakage. However, the dilatancy component of the shear strength diminishes with increasing particle breakage and a considerable amount of dilation occurs on samples with a higher bedding plane, regardless of the extent of particle breakage.