Effect of magnetic field on Cu–water nanofluid heat transfer using GMDH-type neural network

Heat transfer of Cu–water nanofluid over a stretching cylinder in the presence of magnetic field has been investigated. The group method of data handling (GMDH) type neural networks (NNs) is used to calculate Nusselt number formulation. Results indicate that GMDH-type NN in comparison with fourth-order Runge–Kutta integration scheme provides an effective means of efficiently recognizing the patterns in data and accurately predicting a performance. The effects of nanoparticle volume fraction, magnetic parameter and Reynolds number on Nusselt number are studied by sensitivity analyses. The results show that Nusselt number is an increasing function of Reynolds number and volume fraction of nanoparticles while it is a decreasing function of magnetic parameter. As volume fraction of nanoparticles increases, the effect of this parameter on Nusselt number also increases, but opposite behavior is obtained for magnetic parameter and Reynolds number.     

Effects of Raw Material Molar Ratio and Addition of Mg on Titanium Aluminide–Alumina Composite Formation Mechanism

Powder Metallurgy and Metal Ceramics - In this study, the effects of molar ratio of the raw materials (TiO2 and Al) and the addition of Mg on the titanium aluminide–alumina composite...     

Bioethanol Production from Saccharomyces cerevisiae through Conventional and Membrane Batch Fermentation: Experimental and Modeling Studies

Theoretical Foundations of Chemical Engineering - Kinetics for bioethanol production from glucose using Saccharomyces cerevisiae (PTCC 24860) was experimentally studied in a batch membrane...     

Diluted Air Combustion and NOx Emission in a HiTAC Furnace

CFD modeling of NOx emission via N₂O-intermediate mechanism was developed to predict the NOx formation in an experimental furnace equipped with high temperature air combustion (HiTAC) system. The good agreement between the predicted and measured results illustrates the superiority of using a N₂O-intermediate model in prediction of NOx emission during low peak temperature, which happens in HiTAC systems. Moreover, the CFD and measured results show that the flame volume as well as NOx emission significantly depends on temperature and oxygen concentration. Lower NOx emission was experimentally and numerically obtained at lower input oxygen concentration conditions.     

Trajectory-based human action segmentation

This paper proposes a sliding window approach, whose length and time shift are dynamically adaptable in order to improve model confidence, speed and segmentation accuracy in human action sequences. Activity recognition is the process of inferring an action class from a set of observations acquired by sensors. We address the temporal segmentation problem of body part trajectories in Cartesian Space in which features are generated using Discrete Fast Fourier Transform (DFFT) and Power Spectrum (PS). We pose this as an entropy minimization problem. Using entropy from the classifier output as a feedback parameter, we continuously adjust the two key parameters in a sliding window approach, to maximize the model confidence at every step. The proposed classifier is a Dynamic Bayesian Network (DBN) model where classes are estimated using Bayesian inference. We compare our approach with our previously developed fixed window method. Experiments show that our method accurately recognizes and segments activities, with improved model confidence and faster convergence times, exhibiting anticipatory capabilities. Our work demonstrates that entropy feedback mitigates variability problems, and our method is applicable in research areas where action segmentation and classification is used. A working demo source code is provided online for academical dissemination purposes, by requesting the authors.     

A lattice claims model for capital budgeting

Techniques of contingent claims analysis (CCA), extend current capital budgeting practices in two specific ways. First, by explicitly accounting for project uncertainty and second, by quantifying the flexibility value afforded due to the presence of real options. When applied appropriately, CCA techniques can provide a powerful and robust valuation approach and are particularly useful in providing insight to key strategic factors that affect project value. These advantages, however, come at some expense as most applications of CCA to project valuation result in complex partial differential equations which cannot be solved for simple analytic formulas. This, combined with the intricate mathematical structure of these methods often make it difficult for an intuitive grasping and may result in implementation problems. The purpose of this article is to provide a prefatory perspective on the use of CCA techniques as applied to engineering, production, mining, and manufacturing projects. To that end, by using efficient numerical techniques this article formulates a simple and unified CCA framework for valuing a large class of projects that contain real options. The approach is straightforward, readily implementable, and computationally efficient. The framework presented in this paper also provides an important introduction to the use of CCA methods and the quantification of flexibility value in the management of operations     

CFD modeling of a boiler’s tubes rupture

This paper reports the results of a study on the reason for tubes damage in the superheater Platen section of the 320 MW Bisotoun power plant, Iran. The boiler has three types of superheater tubes and the damage occurs in a series of elbows belongs to the long tubes. A three-dimensional modeling was performed using an in-house computational fluid dynamics (CFD) code in order to explore the reason. The code has ability of simultaneous solving of the continuity, the Reynolds-Averaged Navier–Stokes (RANS) equations and employing the turbulence, combustion and radiation models. The whole boiler including; walls, burners, air channels, three types of tubes, etc., was modeled in the real scale. The boiler was meshed into almost 2,000,000 tetrahedral control volumes and the standard k–ε turbulence model and the Rosseland radiation model were used in the model. The theoretical results showed that the inlet 18.9 MPa saturated steam becomes superheated inside the tubes and exit at a pressure of 17.8 MPa. The predicted results showed that the temperature of the steam and tube’s wall in the long tubes is higher than the short and medium size tubes. In addition, the predicted steam mass flow rate in the long tube was lower than other ones. Therefore, it was concluded that the main reason for the rupture in the long tubes elbow is changing of the tube’s metal microstructure due to working in a temperature higher than the design temperature. In addition, the structural fatigue tension makes the last elbow of the long tube more ready for rupture in comparison with the other places. The concluded result was validated by observations from the photomicrograph of the tube’s metal samples taken from the damaged and undamaged sections.     

Computational fluid dynamics modeling of high temperature air combustion in an heat recovery steam generator boiler

This paper reports a numerical study on the possibility of using high temperature air combustion (HiTAC) technique in the heat recovery steam generator (HRSG) boiler of the Fajr Petrochemical Complex, Iran. For this purpose a theoretical fuel nozzle which operates in HiTAC mode of combustion has been installed and modeled using the computational fluid dynamics (CFD) technique. By aim of establishing an efficient heat transfer rate to the boiler’s tubes, the proper nozzle location and an optimum mass flow rate of fuel have been found. The results show that by using this modification it is possible to increase the steam temperature up to 37 percent.     

Probabilistic elderly person’s mood analysis based on its activities of daily living using smart facilities

Pattern Analysis and Applications - The world's population is aging, and eldercare services that use smart facilities such as smart homes are widely common in societies now. With the aid of...     

The CFD Modeling of NOx Emission,HiTAC and Heat Transfer in an Industrial Boiler

NOx emission, heat transfer, and high temperature air combustion (HiTAC) in a boiler of Mobin Petrochemical Complex, Iran was numerically studied. The comparison between the measured values and the CFD predicted results showed good agreement, which implied that the adopted combustion and NOx formation models are suitable for correctly predicting characteristics of the heat recovery steam generation (HRSG) boiler. The predicted results show that NOx emission within the boiler depends highly on temperature, as well as oxygen concentration. Moreover, the influence of the equivalence ratio at a fixed air mass flow rate on the flame temperature and NOx formation has been investigated.