Process intensification aspects for steam methane reforming: An overview

Steam methane reforming (SMR) is the most widely used process in industry for the production of hydrogen, which is considered as the future generation energy carrier. Having been perceived as an important source of H₂, there are abundant incentives for design and development of SMR processes mainly through the consideration of process intensification and multiscale modeling; two areas which are considered as the main focus of the future generation chemical engineering to meet the global energy challenges. This article presents a comprehensive overview of the process integration aspects for SMR, especially the potential for multiscale modeling in this area. The intensification for SMR is achieved by coupling with adsorption and membrane separation technologies, etc., and using the concept of multifunctional reactors and catalysts to overcome the mass transfer, heat transfer, and thermodynamic limitations. In this article, the focus of existing and future research on these emerging areas has been drawn. © 2009 American Institute of Chemical Engineers AIChE J, 2009     

Electrochemical biosensor based on integrated assembly of dehydrogenase enzymes and gold nanoparticles

Development of a highly sensitive nanostructured electrochemical biosensor based on the integrated assembly of dehydrogenase enzymes and gold (Au) nanoparticle is described. The Au nanoparticles (AuNPs) have been self-assembled on a thiol-terminated, sol-gel-derived, 3-D, silicate network and enlarged by hydroxylamine seeding. The AuNPs on the silicate network efficiently catalyze the oxidation of NADH with a decrease in overpotential of approximately 915 mV in the absence of any redox mediator. The surface oxides of AuNP function as an excellent mediator, and a special inverted "V" shape voltammogram at less positive potential was observed for the oxidation of NADH. The AuNP self-assembled sol-gel network behaves like a nanoelectrode ensemble. The nanostructured electrode shows high sensitivity (0.056 +/- 0.001 nA/nM) toward NADH with an amperometric detection limit of 5 nM. The electrode displays excellent operational and storage stability. A novel methodology for the fabrication of a NADH-dependent dehydrogenase biosensor based on the integration of dehydrogenase enzyme and AuNPs with the silicate network is developed. The enzymatically generated NADH is, in turn, electrocatalytically detected by the AuNPs on the silicate network. The integrated assembly has been successfully used for the amperometric biosensing of lactate and ethanol at a potential of -5 mV. The biosensor is very stable and highly sensitive, and it has a fast response time. The excellent performance validates the integrated assembly as an attractive sensing element for the development of new dehydrogenase biosensors.     

Purification, characterization and antitumor activity of L-asparaginase isolated from Pseudomonas stutzeri MB-405

During radiology's early years, many people dedicated their lives to developing practical applications for the x-ray. A leader among them was Ed C. Jerman, author of the first textbook on radiographic technique and founder of the organization known today as the American Society of Radiologic Technologists. Through the first three decades of this century, Jerman worked diligently to bring legitimacy, organization and technical expertise to the fledgling profession of radiologic technology. In 1995, the centennial of the x-ray's discovery, it is appropriate to reflect on the many contributions of the man who is remembered today as the father of modern radiologic technology.     

Evaluation of Mechanical Properties of Solid Propellants in Rocket Motors by Indentation Technique

It is essential to evaluate the mechanical properties of propellants in a solid propellant rocket motor (SPRM) for structural integrity and its performance evaluation before the flight test. Conventionally, uni‐axial tensile testing on an universal testing machine (UTM) is used to evaluate the mechanical properties of solid propellant carton which is cast along with SPRM. Propellants in rocket motors experience various types of loading during storage, transportation, and environmental conditions over the period of time before actual flight whereas the propellant carton doesn’t experience the same as it is stored in magazine. At present, the mechanical properties of propellant cast in a carton are considered to be the mechanical properties of propellant in a rocket motor, which is not truly representative. Therefore, a non‐destructive indentation technique has been used to establish a method for evaluating the mechanical properties of solid propellants in rocket motors based on hydroxyl terminated polybutadiene. The test results obtained using the penetrometer indentation technique was analyzed comprehensively and compared with UTM results. The mathematical correlations were also developed using least square method and established by conducting the penetrometer indentation test on similar propellant composition. Further, the developed correlation was used to evaluate the mechanical properties of propellant in flight SPRM by penetrometer indentation technique.     

Jiles–Atherton Hysteresis Approach in Analyzing the Effect of Field Suppression in Saturated Iron-core Superconducting Fault Current Limiters

Saturated iron-core superconducting fault current limiters (SISFCL) are becoming more popular in the recent years due to their ability of reliable, effective and instantaneous fault limiting. With a superior performance than conventional current limiting methods, the SISFCL is finding its application in modern transmission lines and distribution system. In the SISFCL, the iron core is forced into saturation using a superconducting coil carrying DC current. During a fault in the system, the high fluxes set up in the AC coils interact with the DC flux, thereby reducing the flux density abruptly. This sudden change in the flux density induces a high voltage across the DC coil, which may damage the DC current source as well as the superconducting material. As a protective measure, a field suppressor unit is used that disconnects the DC supply following a fault. In this paper, a mathematical model of the SISFCL is developed considering hysteresis and the effects of the field suppressor unit have been analyzed. The paper also aims to highlight the effects on the performance of SISFCL with varying hysteresis loops of the core material.     

PROBABILITY-ONE HOMOTOPY ALGORITHMS FOR ROBUST CONTROLLER SYNTHESIS WITH FIXED-STRUCTURE MULTIPLIERS

Continuation algorithms that avoid multiplier–controller iteration have been developed earlier for fixed-architecture, mixed structured singular value controller synthesis. These algorithms have only been formulated for the special case of Popov multipliers and rely on an ad hoc initialization scheme. In addition, the algorithms have not used the prediction capabilities obtained by computing the Jacobian matrix of the continuation (or homotopy) map, and have assumed that the homotopy zero curve is monotonic. This paper develops probability-one homotopy algorithms based on the use of general fixed-structure multipliers. These algorithms can be initialized using an arbitrary (admissible) multiplier and a stabilizing compensator. In addition, as with all probability-one algorithms, the homotopy zero curve is not assumed to be monotonic and prediction is accomplished by using the homotopy Jacobian matrix. This approach also appears to have some advantages over the bilinear matrix inequality (BMI) approaches resulting from extensions of the LMI framework for robustness analysis. © 1997 by John Wiley & Sons, Ltd.     

Decarbonised coal energy system advancement through CO2 utilisation and polygeneration

Development of clean coal technology is highly envisaged to mitigate the CO₂ emission level whilst meeting the rising global energy demands which require highly efficient and economically compelling technology. Integrated gasification combined cycle (IGCC) with carbon capture and storage (CCS) system is highly efficient and cleaner compared to the conventional coal-fired power plant. In this study, an alternative process scheme for IGCC system has been proposed, which encompasses the reuse of CO₂ from the flue gas of gas turbine into syngas generation, followed by methanol synthesis. The thermodynamic efficiency and economic potential are evaluated and compared for these two systems. The performances of the systems have been enhanced through systematic energy integration strategies. It has been found that the thermodynamic and economic feasibilities have attained significant improvement through the realisation of a suitably balanced polygeneration scheme. The economic potential can be enhanced from negative impact to 317?M€/y (3.6?€/GJ). The results have demonstrated promising prospects of employing CO₂ reuse technology into IGCC system, as an alternative to CCS system.     

Direct Comparison of SIRT2 Inhibitors: Potency,Specificity, Activity‐Dependent Inhibition,and On‐Target Anticancer Activities

Sirtuin inhibitors have attracted much interest due to the involvement of sirtuins in various biological processes. Several SIRT2‐selective inhibitors have been developed, and some exhibit anticancer activities. To facilitate the choice of inhibitors in future studies and the development of better inhibitors, we directly compared several reported SIRT2‐selective inhibitors: AGK2, SirReal2, Tenovin‐6, and TM. In vitro, TM is the most potent and selective inhibitor, and only TM could inhibit the demyristoylation activity of SIRT2. SirReal2, Tenovin‐6, and TM all showed cytotoxicity in cancer cell lines, with Tenovin‐6 being the most potent, but only TM showed cancer‐cell‐specific toxicity. All four compounds inhibited the anchorage‐independent growth of HCT116 cells, but the effect of TM was most significantly affected by SIRT2 overexpression, suggesting that the anticancer effect of TM depends more on SIRT2 inhibition. These results not only provide useful guidance about choosing the right SIRT2 inhibitor in future studies, but also suggest general practices that should be followed for small‐molecule inhibitor development activities.