Hydraulic experiments on spillway weir profiles

Spillway weirs are the system for regulating the flow in open channel flow passages. Weirs are commonly used to alter the flow of rivers to prevent floods, measure discharge and also in nuclear reactors for uniform cooling purposes. This paper describes the hydraulic experiments conducted for finding the air entrainment on water under laminar flow conditions in open channel flow passage with various profiles of spillway at flow rates in the range of 100–650?lpm. The concept of the spillway system allows stabilisation of the free level of water and avoids variation in the free level of water along the flow passage as a function of flow rate. The main problem in the spillway is the profiling of weir crest. The criteria that need to be satisfied are: (i) there should be no flow separation from the crest and (ii) there should be a uniform circumferential flow to avoid flow asymmetry in the passage. Separation of flow leads to large impact velocity of the falling water, which would lead to large-scale entrainment of air. When flow adheres to the weir crest and upstream, the impact velocity of water with the free surface would be less and hence entrainment would also be less.     

Process factor optimization for controlling pull-down defects in iron castings

Defects in castings lead to non-conformities and affect productivity. Pull-down is a kind of defect occurring in castings. Several factors contribute to pull-down defects. Among those, pouring temperature, carbon equivalent and gating system are more significant. In the first stage, a set of process factors that were contributing to pull-down defect were identified. The identified factors were analyzed using ‘Design of Experiments’ approach. ‘Signal-to-noise’ ratio was estimated. Robust design factor values were estimated from the ‘signal-to-noise’ calculations. ANOVA analysis was done for robust design factor values. The interaction effects within factors were studied and the results were validated using ‘Fisher's test’. In the second stage, optimized factor values were adopted in practical runs. It was identified that the optimized values had improved the acceptance percentage from 86.22% to 96.17%. The improved acceptance percentage had enhanced productivity of the foundry.     

Bioenergetic studies on aerobic growth of Pseudomonas aeruginosa in a single‐substrate media

BACKGROUND: The large‐scale development of various bioprocesses has posed a problem because of the inherent complexities of biological systems. This is because of the lack of discretion in the use of conventional chemical reactors to carry out complex bioreactions. Existing scale‐up methods for bioprocesses are formulated employing offline parameters, i.e. growth rate, substrate uptake rate, oxygen transfer rate and stirring rate per unit volume. Metabolic heat generation is an online process variable portraying the instantaneous activity of any living organism and different types of calorimeters are employed to measure the exothermic heat in non‐invasive way. RESULTS: In this present study an isothermal heat flux biocalorimeter (BioRC1) is employed to monitor the metabolic heat generated due to physiological activity of Pseudomonas aeruginosa cultivated in glucose‐limited growth medium and attempts are made to obtain correlations between metabolic heat and significant process variables. CONCLUSIONS: The value of specific growth rate is determined from correlation developed based on online metabolic heat data and it is found to corroborate with literature value. This finding substantiates the application of calorimetric results to predict the biokinetics parameters for bacterial growth. Copyright © 2009 Society of Chemical Industry     

TiN and TiCN Coated Stainless Steel 316 Ultrosonic Cavitation Probe for High Temperature Application

Silicon - Ultrasonic Cavitation Probe Assisted method in Stir Casting is used to produce metal matrix nano-composites (MMNCs) in bulk quantity with uniform distribution of nano particles. The...     

Optimization of Activated Carbon Preparation from Pomegranate Peel (Punica granatum Peel) Using RSM

This research involves the optimization of different variables of the operating conditions to prepare activated carbon from pomegranate peels (Punica granatum peel). For this purpose, a statistical method called Response Surface Methodology (RSM) has been adopted to economize the number of experiments and their meaningful interpretation. Activated carbon was produced by chemical activation (H₃PO₄). RSM was used to evaluate the variables considered in the preparation of activated carbon such as impregnation ratio (2–4?g H₃PO₄/g pomegranate peel), temperature (400–600°C), and activation time (30–90?min), experimented using a three-variable Box–Behnken Design (BBD) based on a quadratic model and an RSM tool provided by Design Expert 8.0.4 (STAT-EASE Inc., Minneapolis, USA). The responses analyzed for optimization were the methylene blue number and the iodine number. The factors that are significant influencing the activated carbon preparation have been identified by an analysis of variance (ANOVA). The optimum conditions established were impregnation ratio of 2.78, activation temperature of 575°C, and activation time of 73?min.     

A review on conversion techniques of liquid fuel from waste plastic materials

The utilization of plastics has increased in packing sectors consistently, which lead indirectly to increased volumes of plastic wastes posing an environmental threat. Several utilization and recycling techniques of waste plastics are being practiced commercially around the world. In this article, recent conversion techniques of fuel oil from waste plastics and its utilization on a compression‐ignition engine are discussed. Recent statistics says most of the plastic wastes are generated from packing industries that contains polyethylene, polypropylene. In this connection, conversion techniques of polyethylene and polypropylene practiced frequently by researchers include catalytic processing, thermal degradation, and co‐processing. The effect of various parameters like catalysts, reaction temperature, and reaction time of the aforementioned conversion techniques are discussed in this review. Also, few research works about the utilization of waste plastic oil with a compression‐ignition engine along with engine performance and emissions in various blends of diesel with plastic oil are highlighted here. Copyright © 2017 John Wiley & Sons, Ltd.     

Synthesis of MnWO4 nanorods and its electrical and electrochemical properties

The MnWO₄ nanorods were successfully synthesized by surfactant assisted ultrasonics method and characterized its structural (XRD), morphological (SEM) electrical (solid state impedance) and electrochemical (CV) properties. The X-ray diffraction patterns inferred the formation of highly crystalline monoclinic structure of MnWO₄. The formation of nanorods with the aspect ratios of 30–40?nm were reveals from SEM image. The maximum d.c. electrical conductivity was found to be 4.40?×?10^?5?S/cm at 570°C for MnWO₄ nanorods prepared by surfactant assisted ultrasonic method. The quasi-rectangular behavior of cyclic voltammogram inferred the supercapacitive behavior of the prepared MnWO₄ nanorods.     

Identification of uncertain nonlinear systems for robust fuzzy control

In this paper, we consider fuzzy identification of uncertain nonlinear systems in Takagi-Sugeno (T-S) form for the purpose of robust fuzzy control design. The uncertain nonlinear system is represented using a fuzzy function having constant matrices and time varying uncertain matrices that describe the nominal model and the uncertainty in the nonlinear system respectively. The suggested method is based on linear programming approach and it comprises the identification of the nominal model and the bounds of the uncertain matrices and then expressing the uncertain matrices into uncertain norm bounded matrices accompanied by constant matrices. It has been observed that our method yields less conservative results than the other existing method proposed by S?krjanc et al. (2005) [11] and [12]. With the obtained fuzzy model, we showed the robust stability condition which provides a basis for different robust fuzzy control design. Finally, different simulation examples are presented for identification and control of uncertain nonlinear systems to illustrate the utility of our proposed identification method for robust fuzzy control.