Limiting capacities of drainage stack in tall buildings

Inter-relationships developed previously between negative pressure produced in a stack and flow rate to stack diameter ratio have provided a simple procedure for designing both vented and unvented drainage systems in tall buildings. These studies have, however, disregarded existing suctions in the stack.The present work relates to a performance study of Single Stack and Modified One-pipe systems of drainage for existing suctions in the stack, a condition closer to the actual situation in tall buildings. The results of this investigation have been reported in terms of permissible stack capacities and are in close agreement with the recommendations of B.R.E. (U.K.).     

Mn-Doped Zn<Subscript>2</Subscript>SiO<Subscript>4</Subscript> Phosphors Synthesis Using Flame Spray Pyrolysis

Zn₂SiO₄:Mn²⁺ particles are used as green phosphors in plasma display panels and cathode ray tubes. In this study, we report the synthesis of zinc silicate phosphors by flame spray pyrolysis using different Zn-sources and under different process conditions. The XRD and luminescence measurement showed the phosphors prepared from Zn-nitrate source to have better crystallinity and emission characteristics. The luminescence properties of the phosphor particles were found to improve both at higher methane flow rates during pyrolysis and at higher annealing temperatures.     

Chitosan nanocoating on cotton textile substrate using layer‐by‐layer self‐assembly technique

An attempt was made to deposit a nanocoating onto a cotton textile substrate using a layer‐by‐layer self‐assembly approach. Chitosan, a natural biopolymer with polycationic characteristic, was used as a polyelectrolyte along with poly(sodium‐4‐styrene sulfonate) as an anionic polyelectrolyte for the first time on a textile substrate using this technique. The nanocoated surface was evaluated for surface characteristics such as the contact angle and scanning electron microscopy. The effect of ultrasonication during the intermediate washing steps was explored. Ultrasonication during the washing steps clearly helped in depositing more uniform bilayers onto individual fiber surfaces; this contrasted with the deposition of a continuous coating layer, which was nonuniform and had a lot of surface cracks. The use of this novel method for depositing chitosan onto cotton imparted antimicrobial properties to the fabric without adversely affecting its flexibility, feel, or breathability. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Discrete Modeling of Growth of Hairy Roots in a Mist Bioreactor

Hairy root culture is a promising route for large‐scale secondary metabolite production. A discrete model is developed to study the kinetic growth of these valuable roots in a reactor. The growth process is defined to occur in three sequential phases. The elongation rate is modeled as exponential growth with the growth coefficient being dependent on mass transfer coefficient, nutrient concentration difference, and distribution of nutrients in growth and sustenance requirements. Results indicate that the primary root growth is reduced by one‐fifth of its initial growth rate due to the branching process, and the growth of new branches is significantly faster than its primary root growth due to internal transport of nutrients. The model is successfully validated against experimental findings. Its integration with spatio‐temporal variation of nutrients in a reactor will be a crucial input to large‐scale production of hairy roots.     

A fast and efficient computer aided diagnostic system to detect tumor from brain magnetic resonance imaging

In this work, a simple and efficient CAD (computer‐aided diagnostic) system is proposed for tumor detection from brain magnetic resonance imaging (MRI). Poor contrast MR images are preprocessed by using morphological operations and DSR (dynamic stochastic resonance) technique. The appropriate segmentation of MR images plays an important role in yielding the correct detection of tumor. On examination of three views of brain MRI, it was visible that the region of interest (ROI) lies in the middle and its size ranges from 240 × 240 mm² to 280 × 280 mm². The proposed system makes effective use of this information and identifies four blocks from the desired ROI through block‐based segmentation. Texture and shape features are extracted for each block of all MRIs in the training set. The range of these feature values defines the threshold to distinguish tumorous and nontumorous MRIs. Features of each block of an MRI view are checked against the threshold. For a particular feature, if a block is found tumorous in a view, then the other views are also checked for the presence of tumor. If corresponding blocks in all the views are found to be tumorous, then the MRI is classified as tumorous. This selective block processing technique improves computational efficiency of the system. The proposed technique is well adaptive and fast, and it is compared with well‐known existing techniques, like k‐means, fuzzy c‐means, etc. The performance analysis based on accuracy and precision parameters emphasizes the effectiveness and efficiency of the proposed work.     

Use of Waste Bakelite as a Raw Material Resource for Recarburization in Steelmaking Processes

Bakelite is a thermoset plastic commonly found in electronic and automobile components. CaCO₃ is generally found in the polymer as a filler material. Since it cannot be remelted, the disposal of this material has become an environmental issue. The present study investigates a new route to utilize waste bakelite as a source of carbon in EAF steelmaking process. This paper reports the carbon dissolution behaviour of bakelite/coke blends into liquid steel at 1550 °C. The carbon pick up in the liquid steel after reaction with varying blends of bakelite/coke for 30 minutes ranged between 0.13 wt% to 0.17 wt%; these were generally higher than that observed from coke alone (0.1 wt%). The dissolution rate (K) was also found to improve and the observed trend was BK2 (0.045 × 10^?3 s^?1) > BK3 (0.023 × 10^?3 s^?1) > BK1 (0.005 × 10^?3 s^?1) > coke (0.003 × 10^?3 s^?1). The reaction products formed at the interface after 30 minutes of contact between liquid steel and bakelite/coke blends were observed to be a CaS‐Al₂O₃ complex. The presence of CaS in the interfacial layer due to the CaO in the ash, lowered melting temperature of the layer, thereby allowing for increased removal of the ash layer and greater carbon pick‐up. The CaO is formed from the decomposition of CaCO_3, and its presence was found to have a positive effect on modifying the properties of the coke, and thereby enhancing the carbon dissolution behaviour.