Simultaneous Retrieval of Parameters in a Transient Conduction-Radiation Problem Using a Differential Evolution Algorithm

This article deals with the application of the differential evolution (DE) algorithm for the inverse analysis of a transient conduction-radiation heat transfer problem. Thermophysical properties and/or optical properties of the medium are simultaneously retrieved with a known temperature field. The conducting-radiating planar enclosed medium bounded by diffuse-gray boundaries is absorbing, emitting, and scattering. In both the direct and inverse methods, the energy equations are solved using the lattice Boltzmann method (LBM), and the finite volume method (FVM) is used to compute the radiative information. In the inverse method, the objective function is minimized using the DE algorithm. Any two sets of parameters, viz., the extinction coefficient, the scattering albedo, emissivity and conduction-radiation parameter, are simultaneously retrieved. The effects of key DE algorithm parameters, such as the weighting factor and the crossover constant on the quality of solutions, are studied. Measurement errors are accounted. The accuracy of the DE algorithm is compared with the genetic algorithm. The DE algorithm is significantly faster, and it yields the global optimum for a wide range of parameters.     

Contrast enhancement via texture region based histogram equalization

Abstract

This paper presents two novel contrast enhancement approaches using texture regions-based histogram equalization (HE). In HE-based contrast enhancement methods, the enhanced image often contains undesirable artefacts because an excessive number of pixels in the non-textured areas heavily bias the histogram. The novel idea presented in this paper is to suppress the impact of pixels in non-textured areas and to exploit texture features for the computation of histogram in the process of HE. The first algorithm named as Dominant Orientation-based Texture Histogram Equalization (DOTHE), constructs the histogram of the image using only those image patches having dominant orientation. DOTHE categories image patches into smooth, dominant or non-dominant orientation patches by using the image variance and singular value decomposition algorithm and utilizes only dominant orientation patches in the process of HE. The second method termed as Edge-based Texture Histogram Equalization, calculates significant edges in the image and constructs the histogram using the grey levels present in the neighbourhood of edges. The cumulative density function of the histogram formed from texture features is mapped on the entire dynamic range of the input image to produce the contrast-enhanced image. Subjective as well as objective performance assessment of proposed methods is conducted and compared with other existing HE methods. The performance assessment in terms of visual quality, contrast improvement index, entropy and measure of enhancement reveals that the proposed methods outperform the existing HE methods.     

Microwave combination heating: Coupled electromagnetics‐ multiphase porous media modeling and MRI experimentation

The work includes development of a multiphase porous media model and magnetic resonance imaging (MRI) experiments to study microwave combination heating. Combination of electromagnetic, convective and radiant heating was considered. The material being heated was modeled as a hygroscopic porous medium with different phases: solid matrix, water and gas, and included pressure driven flow, binary diffusion and phase change. The three‐dimensional transport model was fully coupled with electromagnetics to include the effect of variable properties. MRI was used to obtain spatial temperature and moisture distributions to validate the model. The model demonstrated that high and low moisture materials behave differently under different combinations of heating and general guidelines for combining heating modes were obtained. Low moisture materials can be heated effectively using higher microwave power which is not possible in high moisture material. Cycling of microwave was found to be useful in distribution of excessive volumetric heat generated by microwaves. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

Comparative Assessment of Trypsin Inhibitor vis-à-vis Kunitz Trypsin Inhibitor and Bowman-Birk Inhibitor Activities in Soybean

Trypsin inhibitor activity (TIA) in soybean is attributed to two polypeptides, namely, Kunitz trypsin inhibitor (KTI) and Bowman-Birk inhibitor (BBI). Standard spectrophotometric protocol widely followed for estimation of TIA is cumbersome and does not distinguish KTI from BBI. In the present investigation, extraction conditions for KTI were optimized and different forms of this polypeptide were resolved in 180 soybean genotypes of Indian and exotic origin through native PAGE. This led to the identification of three KTI alleles, namely, Ti^a, Ti^b, and Ti^c, with Ti^a occurring in most of the Indian genotypes. Trypsin-KTI complex assay exhibited binding of Ti^a polypeptide with 2.51 fold concentration of trypsin. Subsequently, seeds of selected genotypes were subjected to estimation of KTI and BBI activity through densitometry and enzyme-linked immunosorbent assay (ELISA), respectively; and total TIA through standard spectrophotometric protocol. Summation of KTI and BBI was significantly (P?<?0.05) lower than that of TIA determined through the spectrophotometric method.     

Real-time blast furnace hearth liquid level monitoring system

A stable and efficient blast furnace operation requires proper control of hot metal and slag drainage from the hearth. Many operational problems such as non-dry casts, blow outs, excessive hearth lining wear and low-blast intake arise when the liquid level in the hearth exceeds the critical limit where hearth coke and deadman start to float. Since the direct measurement of the hearth liquid level is practically impossible due to high temperature and pressure inside the furnace, it is therefore important to estimate the liquid level in the hearth and display it to the operators on real-time basis for efficient cast management. This paper presents a system, called hearth liquid level monitoring (LLM), which simulates the liquid level and drainage behaviour of the furnace hearth. It is based on the theoretical hot metal and slag generation rate from the specific oxygen rate and the computed drainage rate from torpedo radar signals and the slag flow measurement system. The system advises the blast furnace operator when to initiate tapping and close the taphole when the liquid level is controlled. It also alerts operators when to use the larger drill bit diameter for opening the next cast.     

Plane Registration Leveraged by Global Constraints for Context‐Aware AEC Applications

Abstract: In this article, we propose a new registration algorithm and computing framework, the KEG tracker, for estimating a camera's position and orientation for a general class of mobile context‐aware applications in Architecture, Engineering, and Construction (AEC). By studying two classic natural marker‐based registration algorithms, Homography‐from‐detection and Homography‐from‐tracking, and by overcoming their specific limitations of jitter and drift, our method applies two global constraints (geometric and appearance) to prevent tracking errors from propagating between consecutive frames. The proposed method is able to achieve an increase in both stability and accuracy, while being fast enough for real‐time applications. Experiments on both synthesized and real‐world test cases demonstrate that our method is superior to existing state‐of‐the‐art registration algorithms. The article also explores several AEC applications of our method in context‐aware computing and desktop‐augmented reality.     

A fuzzy logic based approach for modeling quality and reliability related customer satisfaction in the automotive domain

This paper presents an approach to assess quality and reliability related customer satisfaction from field failure data at each individual customer level. The quality satisfaction has been modeled based on number of failures and severity of failures, while, reliability satisfaction has been modeled based on number of visits to dealer and time span between visits. The satisfaction modeled at an individual vehicle (customer) level is further aggregated to a vehicle model level to determine overall satisfaction of customers with that specific vehicle model. A fuzzy logic approach is used to construct the satisfaction model. A grid search technique is used to tune the model parameters such that the output of the model for specific vehicle models matches with survey based ratings assigned to the vehicle models.