Optimizing Concentration of Drag Reducing Polymer in Case of One- and Two-Phase Flow in 90° Copper Elbow

Journal of Failure Analysis and Prevention - The rate of diffusion-controlled corrosion of 90° Copper Elbow by acidified dichromate has been investigated in relation to the following...     

Selective nano alumina supported vanadium oxide catalysts for oxidative dehydrogenation of ethylbenzene to styrene using CO2 as soft oxidant

Nano alumina-supported V₂O₅ catalysts with different loadings have been tested for the dehydrogenation of ethylbenzene with CO₂ as an oxidant. High surface area nano-alumina was prepared and used as support for V₂O₅ as the catalyst. The catalysts were synthesized by impregnation techniques followed by calcinations and microwave treatment, denoted as V₂O₅/γ-Al₂O₃-C and V₂O₅/γ-Al₂O₃-MW, respectively. The V₂O₅ loading was varied on nano-alumina from 5 to 30 wt%. The support and catalysts were characterized by X-ray diffraction (XRD), Barett–Joyner–Halenda (BJH) pore-size distribution, N₂-adsorption isotherms, Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and temperature programed desorption (TPD-NH₃). The characterization results indicated that V₂O₅ is highly dispersed on alumina up to 30%-V₂O₅/γ-Al₂O₃-MW prepared by MW method. The TPD studies indicated that there are significant differences in acid amount and strength for V₂O₅/γ-Al₂O₃-C and V₂O₅/γ-Al₂O₃-MW-catalysts. The catalytic activity of the prepared catalysts was evaluated in the temperature range 450–600 °C in relation to the physicochemical properties and surface acidity. The results revealed that optimum catalytic activity and selectivity (～100%) toward styrene production were obtained using 10% V₂O₅/γ-Al₂O₃-MW catalyst treated with microwave.     

A PC based state estimator interfaced with a remote terminal unitplacement algorithm

In this paper a new remote terminal unit (RTU) placement algorithm is presented. The objective of this algorithm is to place a minimum set of RTUs which satisfies three important constraints of the problem-observability, absence of critical measurements, and reliability requirements defined in terms of RTU loss. The problem is solved in a single stage. The results of this algorithm are interfaced with a linear programming (LP) state estimator. This estimator only uses the voltage measurements, and the active and reactive power flows in the lines for the development of the coupled state-estimation Jacobian H-matrix. The injection measurements are not currently included, though in practice they can be easily added to the estimator model. The inclusion of the injection measurements will enlarge the use of the presented algorithm. The RTU placement algorithm and its link with the LP estimator are tested on IEEE standard bus systems. Using the proposed RTU set, the test results presented show that the LP estimator has very good filtering capabilities when operated with or without bad data, and that the loss of any RTU does not have any significant impact on the solution     

Ultrasonic investigation of some rubber blends

Compression ultrasonic velocity, longitudinal ultrasonic absorption, and heat of mixing for NR-BR, NR, NBR, and NR-IIR rubber blends were measured. Results show the applicability of examining the compatibility degree by using longitudinal ultrasonic absorption techniques. Results showed that NR-BR blends are compatible, whereas NR-NBR and NR-IIR blends are semicompatible and incompatible, respectively.     

Load distribution in osseointegrated implant supporting extended and non extended dentures

There is a controversy among prosthodontists concerning the most favourable superstructure design of a prosthesis supported by implants. Some investigators used the fully extended denture, others used a non extended. This study evaluated the load distribution pattern occurring in implants with the two designs. A real clinical situation which includes 4 osseointegrated implants that are connected to each other with a superstructure bar and support an acrylic dentures was transferred into a 3-D geometric model. With the 3-D FEM it was possible to compare between the two types of acrylic dentures.     

Some changes in cottonseed oil during frying of flafel and eggplant

The changes in the characteristics, composition and technological properties of cottonseed oil during heating for 50 h at 200°C in the presence of air were studied. The effects of the heated oil in frying two types of Egyptian vegetable—flafel and eggplant—were also examined. The results showed that as the heating time of the oil increased: (a) the free fatty acids increased and both iodine value and peroxide number decreased; (b) the triglycerides hydrolysed and (c) the loss of oil weight, the tendency of oil to foam and the time necessary to fry the vegetable increased.     

Combining lectin microcolumns with high-resolution separation techniques for enrichment of glycoproteins and glycopeptides

Silica-based lectin microcolumns are described in this study together with the chemical procedures necessary for their preparation. The analytical merits of Canavalia ensiformis and Sambucus nigra lectins, [immobilized on activated macroporous silica], such as binding capacity, trapping reproducibility, and substrate selectivity, have been evaluated using model glycoproteins. The described microcolumns are applicable to high-pressure analytical schemes utilizing microvalving procedures, washing steps, and quantitative desorption for LC/MS analysis. The described analytical systems are amenable to the applications aiming at fractionation of complex glycopeptide mixtures and determination of the sites of glycosylation.     

Fracture mechanics approach for flexural strengthening of reinforced concrete beams

This paper reports on the experimental testing of 9 notched reinforced concrete specimens under four point bending. The beams comprise three beam sizes and three tension reinforcing steel ratios. All beams have constant span/depth ratio of 4, initial notch/depth ratio of 0.3. Two strengthening fiber laminates were used: Glass fiber for the two lower tension reinforcing steel ratios and Carbon fiber for the higher tension reinforcing steel ratio. The strengthening laminates were designed to enhance beam moment capacity by 15% to 150% depending on the beam size and reinforcement ratio. To simulate real life strengthening situations, beams were first loaded until the notch propagated to 0.5 the beam depth. The strengthening fiber laminate was then introduced to the tension side of the beam while the load was kept applied to the other side of the beam. The fracture moment for a given crack depth was calculated through an analytical algorithm which employs Linear Elastic Fracture Mechanics. The approach takes into consideration the previous loading history of the beam prior to introducing the strengthening laminate. Test measurements of crack extension and applied load were used to compare the fracture moment recorded experimentally to that one calculated analytically. The application of the solution algorithm to different specimen sizes–cross-section dimensions, reinforcement ratio, and strengthening fiber laminate–showed that the solution algorithm is able to effectively predict the behavior of larger beam size and/or reinforcement better than that of smaller beam size and/or reinforcement. A sensitivity analysis was conducted to explore this point.     

Determination of salsolinol and related catecholamines through on-line preconcentration and liquid chromatography/atmospheric pressure photoionization mass spectrometry

A new analytical approach has been developed for simultaneous measurements of endogenous salsolinol and major catecholamines in brain tissue of experimental animals. This procedure involves a combination of on-line phenyl boronate affinity preconcentration and microcolumn liquid chromatography, followed by mass spectrometry equipped with an atmospheric pressure photoionization (APPI) source. Flow conditions of the APPI source were optimized for detection sensitivity while different dopants were evaluated. The on-line preconcentration was found essential for the sensitivity requirements of salsolinol measurements in the brain tissue from alcohol-preferring rats subjected to different levels of alcohol exposure.