CFD simulation of acoustic cavitation in a crude oil upgrading sonoreactor and prediction of collapse temperature and pressure of a cavitation bubble

In acoustic cavitation, high pressure and temperature are generated due to cavitation bubble collapse in the liquid bulk around the bubble which causes physical and chemical changes in the liquid. In this study, pressure distribution in water caused by ultrasonic wave propagation in a sonoreactor was investigated. Active cavitation zones were determined by calculating acoustic pressure threshold for cavitation inception and compared with experimental results. Collapse pressure and temperature were predicted 3000 atm and 3200 K, respectively, for crude oil at temperature of 25 °C by evaluating cavitation bubble dynamics in the exerted acoustic field. As a consequence, the huge amounts of energy generated by this phenomenon can be applied for changes in oil properties and crude oil upgrading.     

Evolution of Emergency Management in Malaysia

Various types of disaster ranging from biological, structural collapse, fire and explosion, landslides and meteorological incidents have struck Malaysia. Safety and emergency laws and regulations in Malaysia had evolved in pace with the development and industrialisation of the country. Some of these disasters were land‐marked disasters whereby various safety and emergency acts and regulations were amended or introduced. In this article, the history of the evolution of various Safety and Emergency Laws, Regulations and Acts in the country since independence in 1957 until the establishment of the Permanent Guidelines for Disaster Management and Relief Operations in 1997 is presented. Lessons from past disasters and the rapid expansion of industrialisation have greatly influenced the evolution of safety and emergency management in Malaysia. However, this intermediary phase in the pursuit of development is often accompanied by an increase in vulnerability (McEntire, 1997). This paper discusses reasons that are attributed to the increase in vulnerability as well as the challenges faced by the nation in the area of safety and emergency planning.     

Finite element analysis of laser inert gas cutting on Inconel 718

Inconel 718 has high strength, which makes it difficult to cut using conventional cutting methods. In the present study, the laser inert gas cutting of Inconel 718 was simulated by finite element analysis software ANSYS. Finite element method was used to predict thermal stress and kerf width formation during the laser cutting process. ANSYS Parameter Design Language was used to model the Gaussian-distributed heat flux from the laser beam acting on the workpiece. The removal of melted material during laser cutting to form the kerf width was modeled by employing the element death methodology in ANSYS. In addition, laser cutting was simulated at continuous wave (CW) and the effects of laser power and cutting speed on kerf width were investigated. A series of experiments were carried out to verify the predictions. The temperature fields on the workpiece were measured using thermocouples. The kerf width size was measured using a profile projector, whereas the metallurgical and morphological changes at the cutting edge were examined using scanning electron microscopy. A good correlation was found between the simulation and experimental results.     

A survey of temporal decorrelation from spaceborne L-Band repeat-pass InSAR

In this paper we quantify the effects of temporal decorrelation in repeat pass synthetic aperture radar interferometry (InSAR). Temporal decorrelation causes significant uncertainties in vegetation parameter estimates obtained using various InSAR techniques, which are desired on a global scale. Because of its stochastic nature temporal decorrelation is hard to model and isolate. In this paper we analyze temporal decorrelation statistically as observed in a large swath of SIR-C L-Band InSAR data collected over the eastern United States, with a repeat pass duration of one day in October 1994 and a near zero perpendicular baseline. The very small baseline for this particular pair makes the effect of volumetric scattering on correlation magnitude statistics nearly imperceptible, allowing for a quantitative analysis of temporal effects alone. The swath analyzed in this paper spans more than a million hectares of terrain comprised primarily of deciduous and evergreen forests, agricultural land, water and urban areas. The relationships of these different land-cover types, phenology and weather conditions (i.e. precipitation and wind) on the measures of interferometric correlation is analyzed in what amounts to be the most geographically extensive analysis of this phenomenon to date.     

Design of an RMPC with a time‐varying terminal constraint set for tracking problem

This paper presents a robust model predictive control algorithm with a time‐varying terminal constraint set for systems with model uncertainty and input constraints. In this algorithm, the nonlinear system is approximated by a linear model where the approximation error is considered as an unstructured uncertainty that can be represented by a Lipschitz nonlinear function. A continuum of terminal constraint sets is constructed off‐line, and robust stability is achieved on‐line by using a variable control horizon. This approach significantly reduces the computational complexity. The proposed robust model predictive controller with a terminal constraint set is used in tracking set‐points for nonlinear systems. The effectiveness of the proposed method is illustrated with a numerical example. Copyright © 2015 John Wiley & Sons, Ltd.     

Preparation and characterization of a new coagulant based on the sago starch biopolymer and its application in water turbidity removal

A new organic coagulant, sago starch (SS)‐graft‐polyacrylamide (PAm), was prepared by the ceric‐ion‐induced redox polymerization of acrylamide (Am) onto SS at room temperature. The effects of the variation of the concentration of Am and the initiator on the percentages of yield and total conversion were investigated. The chemical composition, viscosity, and side‐chain‐average molecular weight of the obtained graft copolymers were determined. The newly obtained coagulant was tested for the treatment of the turbidity of water. The SS‐g‐PAm coagulants were found to achieve water turbidity removal up to 96.6%. The results of this study suggest that SS‐g‐PAm copolymer is a potential coagulant for reducing turbidity during water treatment. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Retracted: Efficient separation of Nannochloropsis salina using minerals to optimize algae sedimentation

The following article from the Journal of Chemical Technology and Biotechnology, Efficient separation of Nannochloropsis salina using minerals to optimize algae sedimentation by Razi Epsztein, Amichai Felder, Alex Mishelevitz and Vitaly Gitis, published online on 20 March, 2012 in WileyOnlineLibrary ( http://onlinelibrary.wiley.com ; doi: 10.1002/jctb.3754), has been retracted by agreement between the authors, the journal Editor in Chief, Jack Melling and John Wiley & Sons. The retraction has been agreed following an investigation by the academic ethics code committee of Ben‐Gurion University which decided that the corresponding author had no right to publish the results of the study without permission from the other authors (decision from 21 June 2012). Copyright © 2012 Society of Chemical Industry     

Graft copolymerization of methyl methacrylate onto sago starch using ceric ammonium nitrate and potassium persulfate as redox initiator systems

The graft copolymerization of methyl methacrylate (MMA) onto sago starch was carried out in aqueous media by different initiators of ceric ammonium nitrate (CAN) and potassium persulfate (PPS) and under a nitrogen gas atmosphere. Using CAN as an initiator, the maximum percentage of grafting (%G) was ascertained to be 246% at the following optimum conditions: a 70°C reaction temperature, a 2‐h reaction period, 2.0 mmol of CAN, 0.4 mmol of nitric acid, and 141 mmol of MMA. The maximum %G achieved with PPS as the initiator was 90%. The optimum conditions were a 50°C reaction temperature, a 1.5‐h reaction period, 47 mmol of monomer, and 1.82 mmol of PPS. The grafting of MMA onto sago starch was confirmed by the IR spectra of pure sago starch, MMA, and MMA grafted sago starch. This material may have application as a biodegradable plastic. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1375–1381, 2001