Optimization of nitrilase production from a new thermophilic isolate

A new thermostable nitrilase‐producing isolate identified as Streptomyces sp. MTCC 7546 has been studied extensively for the optimization of enzyme production operating in batch mode. The benzonitrile was observed as inducer of nitrilase production. The isolate showed maximum nitrilase production after 24 h of incubation at optimal conditions. The strain grows well on a variety of carbon sources and produces the nitrilase that catalyses the hydrolysis of nitriles to acids without formation of amides. The enzyme is mostly active against mono‐ and di‐aliphatic nitriles (10 mmol L^?1) at pH of 7.4 and at a temperature of 50 °C. Copyright © 2007 Society of Chemical Industry     

A Linear Variable Differential Capacitive Transducer for Sensing Planar Angles

A linear variable differential capacitive transducer for the measurement of planar angles (from 0deg to 360deg) is presented in this paper. The sensor part of the transducer is made of parallel plates of standard and easy-to-fabricate shapes, and the signal-conditioning electronics are realized, employing a couple of simple relaxation oscillators. The output of the transducer is only dictated by a pair of dc reference voltages, and hence, high accuracy and linearity over the entire range (from 0deg to 360deg) are easily obtained by the use of precision dc reference voltages. Detailed analysis indicates that the sensitivity of the transducer is minimal for variations in different parameters. Experimental results obtained on a prototype transducer that has been built and tested establish the efficacy of the proposed transducer. The worst-case error of the prototype transducer is found to be less than 0.1%.     

Stereo error detection, correction, and evaluation

An algorithm is presented for error detection and correction of disparity, as a process separate from stereo matching, with the contention that matching is not necessarily the best way to utilize all the physical constraints characteristic to stereopsis. As a result of the bias in stereo research towards matching, vision tasks like surface interpolation and object modeling have to accept erroneous data from the stereo matchers without the benefits of any intervening stage of error correction. An algorithm which identifies all errors in disparity data that can be detected on the basis of figural continuity and corrects them is presented. The algorithm can be used as a postprocessor to any edged-based stereo matching algorithm, and can additionally be used to automatically provide quantitative evaluations on the performance of matching algorithms of this class     

Parameter Estimation in Water Distribution Networks

Estimation of pipe roughness coefficients is an important task to be carried out before any water distribution network model is used for online applications such as monitoring and control. In this study, a combined state and parameter estimation model for water distribution networks is presented. Typically, estimation of roughness coefficient for each individual pipe is not possible due to non-availability of sufficient number of measurements. In order to address this problem, a formal procedure based on K-means clustering algorithm is proposed for grouping the pipes which are likely to have the same roughness characteristics. Also, graph-theoretic concepts are used to reduce the dimensionality of the problem and thereby achieve significant computational efficiency. The performance of the proposed model is demonstrated on a realistic urban water distribution network.     

Active power filters — Recent advances

Power electronic loads inject harmonic currents into the utility causing overheating of power transformers and neutral wires, the power system, unpredictable performance of protection systems etc. In addition, electric resonances in such loads can also cause other undesirable phenomena like voltage fluctuations, ratio frequency interference (RFI) etc. To mitigate these undesirable effects, a new class of power electronics equipment (Active Filters) is being considered. A review of present-day solutions in the area of active filters is conducted in this paper. Finally, this paper discusses the trends in the design of active filters and the factors influencing them.     

Isolation of ellagic acid from the aqueous extract of the roots of Decalepis hamiltonii: Antioxidant activity and cytoprotective effect

Roots of Decalepis hamiltonii are consumed as pickles and as a beverage and are believed to possess health-promoting properties. Roots of D. hamiltonii exhibit antioxidant properties. We have isolated an antioxidant compound from the aqueous extract of the roots of D. hamiltonii and identified it as ellagic acid (EA), based on NMR and MS. EA exhibited free radical-scavenging activity, inhibited LDL oxidation and showed cytoprotective effect against xenobiotic-induced oxidative stress in Ehrlich Ascites tumor cells. EA is a new addition to the list of antioxidant compounds in the roots of D. hamiltonii.     

Build-Operate-Transfer-Type Procurement in Asian Megaprojects

Lessons are drawn from the recent resurgence in public-private partnerships for the procurement of large scale infrastructure, with a focus on Asian megaprojects. BOT (build-operate-transfer)-type win-win cooperation aligns well with the paradigm shift that has repeatedly been called for in addressing construction industry shortfalls. However, the many volatile variables involved and the limited experience in dealing with the special risks encountered highlights the need for decision support frameworks to evaluate and select the optimal from among: (1) potential BOT-type projects; (2) prospective franchisees; and (3) innovative project financing packages. Such frameworks should include appropriate success criteria and indicators for their evaluation. Benchmarking of good practices would establish reasonable ranges of values for such indicators. Identification of critical success factors, classifications of common risks, and comparisons of recent experiences on BOT-type projects lead to recommendations for the development of a “BOT body of knowledge” with related guidelines and toolkits. These would assist both public and private sector decision makers considering BOT-type modalities to attain multiple win-win-win targets that benefit their respective interests, as well as those of the general public end users.     

Hong Kong Experience in Managing BOT Projects

BOT (build-operate-transfer) project delivery systems have provided effective routes to mobilize private sector funds, innovative technologies, management skills, and operational efficiencies for public infrastructure development. However, many countries and regions lack BOT expertise and experience. Hong Kong, one of the pioneers in optimizing private sector participation in infrastructure development, has developed five large tunnels on the BOT basis since the late 1960s, the first of which recently completed its franchise period and entered into the posttransfer operation phase. Experience and lessons gained in formulating and managing BOT projects over more than 30 years have enabled the Hong Kong government to develop a well-structured BOT framework. This proven BOT model is useful for countries and regions lacking such expertise and still in need of BOT-based infrastructure. This paper discusses key development aspects of the five BOT tunnels, including feasibility study; tender selection; legal, financial, and land issues; design and construction; operation and maintenance; transfer; and posttransfer management.     

Characterization of Ce0.9Gd0.1O1.95 powders synthesized by spray drying

Ce_0.9Gd_0.1O_1.95 powders were synthesized by spray drying and successive calcinations. The phase purity, BET surface area, and particle morphology of as-sprayed and calcined powders were characterized. After calcination above 300 °C, the powders were single phase and showed a BET surface area of 68 m²/g when calcined at 300 °C. The conductivity, in air, of sintered pellets was measured by electrochemical impedance spectroscopy (EIS) and it was found to be comparable with literature values. The activation energy for the total conductivity was around 0.83 eV. The powder calcined at lower temperature showed better sinterability and higher total conductivity due to an increased bulk conductivity.