Dissociation of polar oil components in low salinity water and its impact on crude oil–brine interfacial interactions and physical properties

Despite many efforts into the study of fluids interaction in low salinity water flooding, they are not probing the basics of transport phenomena between the involved phases. This work is aimed to bring new understanding of fluid–fluid interaction during low salinity water flooding through a series of organized experiments in which a crude oil sample with known properties was kept in contact with different brine solutions of various ionic strengths. Measuring brine pH, conductivity and crude oil viscosity and density for a period of 45 days illustrates the strong effect of the contact time and ionic strength on the dissociation of polar components and physical properties of the crude oil and brine. Besides, the interfacial tension (IFT) measurements show that the interfacial interactions are affected by several competitive interfacial processes. By decreasing the ionic strength of the brine, the solubility of naphthenic acids in the aqueous solution increases, and hence, the conductivity and the pH of the aqueous phase decrease. To verify this important finding, UV–Vis spectroscopy and 1H NMR analysis were also performed on aged brine samples. Notably, there is an ionic strength of brine in which the lowest IFT is observed, while the other physical properties are remained relatively unchanged.     

Understanding of attachment efficiency and induction time between bubbles and pyrite particles in flotation

The fundamental flotation models are useful for understanding flotation mechanisms. However, these models cannot be used for design and optimization of flotation circuits because it is very difficult to determine induction times experimentally during flotation despite using advanced high-speed cameras. Thus, there is a need to develop the model that can be used for practical applications, which is the main objective in this work. The developed models were successful in predicted P_a (attachment efficiency) and t_i (induction time) at various chemical conditions. The values of P_a (attachment efficiency) were strongly affected by particle size, collector concentration and pulp pH while the values of t_i (induction time) were affected by particle size and collector concentration and the values of k (flotation rate constant) were affected by collector concentration only. It means that P_a is much more sensitive than t_i and k to detect the changes in the flotation experimental conditions. The slopes of t_i vs P_a functions were larger at different particle sizes than those at different collector concentrations, demonstrating that the effect of particle size was more dominant than the effect of collector concentration on P_a. This paper demonstrated that understanding of P_a is essential for better analysing flotation mechanisms.     

Influence of slip length on filtration performance of fine particles

Fine particle filtration has been known to become progressively inefficient as the filter cake builds up owing to restricted movement of liquid through the small cavities formed in the cake. In different chemical industries, this restricts higher throughput rates and also results in higher transportation costs due to increase in moisture content. This paper discusses the influence of using a surfactant, DAH (dodecylamine hydrochloride), in enhancing the filtration rate of a finely ground particles and the reduction of moisture content in the cake. The observed enhanced filtration rate has been attributed to a reduction in the resistance to liquid flow due to the increase in hydrophobicity at the particle surface. The resulting enhanced filtration rate has been modelled by superimposing a slip velocity at the boundary of the capillaries formed in the cake. The model evaluates the cake and medium resistances by incorporating a slip length into the filtration equation which varies with the concentration of hydrophobic reagent and the effective size of capillaries. The increase in filtration rate is more pronounced for finer particle slurries. Also, it has been observed that the moisture content of the filter cakes formed was reduced.     

In-depth study of mechanical properties of poly(lactic acid)/thermoplastic polyurethane/hydroxyapatite blend nanocomposites

Journal of Materials Science - The present study evaluates the effect of adding different contents of hydroxyapatite (HA) nanoparticles on the mechanical properties of poly(lactic...     

Probabilistic Event Based Rainfall-Runoff Modeling Using Copula Functions

Multivariate probability analysis of hydrological elements using copula functions can significantly improve the modeling of complex phenomena by considering several dependent variables simultaneously. The main objectives of this study were to: (i) develop a stand-alone and event-based rainfall-runoff (RR) model using the common bivariate copula functions (i.e. the BCRR model); (ii) improve the structure of the developed copula-based RR model by using a trivariate version of fully-nested Archimedean copulas (i.e. the FCRR model); and (iii) compare the performance of the developed copula-based RR models in an Iranian watershed. Results showed that both of the developed models had acceptable performance. However, the FCRR model outperformed the BCRR model and provided more reliable estimations, especially for lower joint probabilities. For example, when joint probabilities were increased from 0.5 to 0.8 for the peak discharge (q_p) variable, the reliability criteria value increased from 0.0039 to 0.8000 in the FCRR model, but only from 0.0010 to 0.6400 in the BCRR model. This is likely because the FCRR considers more than one rainfall predictor, while the BCRR considers only one.

     

Synthesis of copolymers of a linoleic acid derivative and properties of the copolymer films

Addition copolymers of maleic anhydride and a commercially available conjugated fatty acid, Pamolyn 380, were synthesized via thermal initiation. The copolymers had moderately high molecular weights and were obtained in reasonable yields. The copolymers were characterized by nuclear magnetic resonance and infrared spectroscopy and by elemental analysis. Based on this analytical data and examples from the literature, the copolymers were assigned regularly alternating chain morphology. Coatings were formulated with the copolymers, and films over a metal substrate were evaluated. The films were found to have excellent solvent resistance, high hardness, and good gloss. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 261–267, 2001     

Special all-round fillet weld for anchor rods of base-plate T-stub connections

The eccentricity between connected steel parts and the anchor rods in base-plate T-stub connections makes base plates the weaker components in tension and compression. Additionally, the oversized holes in base plates lead to irregular placement of anchor rods, resulting in an unsymmetrical shear behavior. Thus, this paper aims to develop a special all-round fillet weld to connect the anchor rods beneath the base plate concentrically to the steel part, removing the base plate from the load-transferring chain. Accordingly, design criteria were first developed based on Eurocode's directional method considering all the potential failure modes. Next, results were validated by conducting experimental work. The digital image correlation technique (DIC) was also used to capture the strain distribution developed over the tested specimen till failure. Consequently, numerical analysis was carried out to investigate the fracture strength and the fracture angle and compare the special fillet weld with its equivalent standard one, which has the same weld volume. The results indicated that the proposed design criteria produced safe strength prediction for the developed special all-round fillet weld. Furthermore, the results revealed that using a special all-round fillet weld instead of the equivalent standard one can increase the strength by about 8% and improve the ductility of the weld. However, it decreases the stiffness of the weld by about 21%. The fracture surface occurred at $15°$ from the face of the anchor rod, which produced a higher strength than the predicted tensile strength calculated according to the theoretical throat plane.     

Thermodynamic evaluation of integrated gasification combined cycle: Comparison between high‐ash and low‐ash coals

In the present study, a coal‐integrated gasification combined cycle power plant is simulated. A high‐ash coal and low‐ash coal are considered to compare the performance of the plant. The combined cycle is in typical commercial size with 450 MW capacity. The feeds are Tabas and Illinois #6 coals which approximately contain more than 30% and 10% ash and have higher heating values of 22.7 MJ/kg and 26.8 MJ/kg, respectively. Energy and exergy analyses are done by aspen plus ^® and ees , respectively. Energy analysis shows that the overall efficiencies of power plants using high‐ash and low‐ash coals are 33% and 28%, respectively. The result shows that in high‐ash case, 52 kg/s coal, 10 kg/s water, and 1050 kg/s air and in low‐ash case, 48 kg/s coal and 820 kg/s air are required for providing mentioned power, approximately. Exergy analysis shows that maximum exergy destruction is in heat recovery steam generator unit. Investigating the emissions shows that high percent of ash in the coal composition has slight effects on the IGCC pollution. Finally, from thermodynamic viewpoint, it is concluded that the high‐ash coal, like the conventional one, can be used as thermally efficient and environmentally compatible feed of IGCCs. Copyright © 2016 John Wiley & Sons, Ltd.     

Investigating the possibility of Sonofusion in Deuterated acetone

In this article, energetic implosion of a single vapor bubble induced by a standing acoustic wave is theoretically studied and the Sonoluminescing bubble parameters involved in Sonofusion in Deuterated acetone (C₃D₆O) are investigated. Parameters such as radius, wall velocity, interior temperature and pressure of the bubble influenced by various driving pressure amplitudes in Deuterated acetone at ∼0 °C are investigated. Based on the obtained results, the possibility of thermonuclear fusion inside imploding cavitation bubbles is discussed. The interior pressure of C₃D₆O vapor bubbles at the collapse time is extremely high and the increase of the pressure amplitude increases the pressure inside the bubble. Our findings reveal that the maximum temperature inside acoustic-induced cavitation bubble in Deuterated acetone increases with the acoustic pressure amplitude and it is much higher than the maximum temperature inside acoustic induced cavitation bubbles in liquids such as water and acids. Consequently, the calculated temperature at the pressure amplitude of 7.23 bar was about 3.7 × 10⁵ K and it is predicted that at the reported experimental condition, the case of a bubble cluster subjected to the pressure amplitude of about 15 bar, the temperature inside the bubble reaches to 1.2 × 10⁶ K.