Performance Improvement of Grinding of SiC Using Graphite as a Solid Lubricant

Grinding is a widely employed finishing process for different materials. It is inherently characterized by its high specific energy requirement unlike other machining processes. This leads to a high grinding zone temperature, which impairs the workpiece quality by inducing thermal damage in the form of surface and subsurface cracks, phase transformations, tensile residual stresses, etc. The microcracks and residual stresses induced in the surface of the ceramics during grinding can severely limit the application of ceramic components. This article deals with an investigation on using graphite as a solid lubricant to reduce friction and thereby improve the surface integrity of ground silicon carbide (SiC). An experimental setup has been developed, and experiments have been conducted to study the effect of using a graphite lubricant on the surface roughness, grinding forces, and specific energy while grinding SiC material. Results indicate that there is a considerable improvement in the performance of grinding SiC using graphite as a solid lubricant when compared with dry grinding in terms of specific energy requirements, surface roughness, and damage. The employment of graphite as a solid lubricant in ceramic grinding makes the process more economical and reliable.     

Epitaxial growth of CdTe on Si through perovskite oxide buffers

For the first time, nanometer-thin perovskite oxide buffers have been used to accommodate the lattice mismatch between CdTe epitaxial layers and Si substrates. The resulting CdTe is single crystal with quality comparable to that grown by the more mature technology using micron-thick ZnTe or CdTe buffers. This shows that the use of nanometer-thin perovskite oxide buffers is a promising approach for the epitaxial growth of II–VI compounds on Si.     

(n +p)-node realizability of Y-matrices of (n + 1)-node resistance n-port networks

Sufficient conditions are established for the (n +p)-node, p>2, realizability of Y-matrices of (n + 1)-node resistance n-port networks. It is shown that these conditions are a generalization of the previous known results for p = 2 and p =n.     

Recognition and Classification of Pomegranate Leaves Diseases by Image Processing and Machine Learning Techniques

Disease recognition in plants is one of the essential problems in agricultural image processing. This article focuses on designing a framework that can recognize and classify diseases on pomegranate plants exactly. The framework utilizes image processing techniques such as image acquisition, image resizing, image enhancement, image segmentation, ROI extraction (region of interest), and feature extraction. An image dataset related to pomegranate leaf disease is utilized to implement the framework, divided into a training set and a test set. In the implementation process, techniques such as image enhancement and image segmentation are primarily used for identifying ROI and features. An image classification will then be implemented by combining a supervised learning model with a support vector machine. The proposed framework is developed based on MATLAB with a graphical user interface. According to the experimental results, the proposed framework can achieve 98.39% accuracy for classifying diseased and healthy leaves. Moreover, the framework can achieve an accuracy of 98.07% for classifying diseases on pomegranate leaves.     

Simple Method to Evaluate the Ballistic Properties for Gas Generant Compositions

Combustion, Explosion, and Shock Waves - The study of the ballistic properties of energetic materials remains vital to ensure safety during their transportation, handling, storage, and processing....     

Investigation on the working performance of partitionable-space enhanced coagulation reactor

In this study, the phosphorous removal efficiency of partitionable-space enhanced coagulation (PEC) technology has been investigated. A series of continuous experiments was conducted to find out the influence of operating parameters. With increase in the elapsed treatment time, the phosphorus removal rates improved progressively during 1.5–3 h and the reactor reached a steady state after 4 h. This improved performance is mainly attributed to the partitionable-space and “flocculation filter” in the PEC reactor which enhanced the coagulation process. The flocs formed exhibited excellent settling characteristics by quickly settling out within the first 15 min.     

Three-Dimensional Electromechanical Impedance Model. I: Formulation of Directional Sum Impedance

Piezoceramic transducers (PZTs) are extensively used in vibration and noise control, and damage detection of various engineering structures. In the last decade, its application has been extended to include their interactions with the host structure in electromechanical impedance models. The interaction between the host structure and PZT is governed by both the extensional and longitudinal vibrations of the transducer. However, the interaction models developed in the last decade consider only the one-dimension or two-dimension extensional actuations, ignoring the longitudinal actuations. This study examines the three-dimensional (3D) interaction of a transducer with the host structure, considering both the extensional and the longitudinal actuations of the transducer. It does not impose any restriction on the shape, size, and electrical properties of the PZT and thus contains additional features over the existing PZT-structure interaction models. This paper is Part I of a two-part paper, which presents a new “directional sum” numerical–analytical admittance formulation with experimental verification. Part II of this paper will elaborate on the damage analysis and characterization of PZT properties for the new 3D model.     

Flexural bond strength of masonry using various blocks and mortars

This paper deals with an experimental study on flexural bond strength of masonry using various blocks in combination with different mortars. Flexural bond strength of masonry has been determined by testing stack-bonded prisms using a modified bond wrench test set-up. The effect of mortar composition and strength on the masonry's flexural bond strength using three types of masonry units (stabilized mud blocks, stabilized soil-sand blocks and burnt brick) has been examined. The effect of the masonry unit's moisture content on flexural bond strength has also been studied. Increases in mortar strength lead to increased flexural bond strength for cement mortar, irrespective of the type of masonry unit. It has been found that combination mortars, such as soil-cement mortar and cement-lime mortar, lead to better bond strength compared to cement mortars. The moisture content of the masonry unit at the time of casting has displayed significant influence on the flexural bond strength of the masonry. It has been found that for each type of masonry unit, an optimum moisture content exists, beyond which the flexural bond strength falls off quickly.     

Phrase-based correction model for improving handwriting recognition accuracies

We propose a method for increasing word recognition accuracies by correcting the output of a handwriting recognition system. We treat the handwriting recognizer as a black box, such that there is no access to its internals. This enables us to keep our algorithm general and independent of any particular system. We use a novel method for correcting the output based on a “phrase-based” system in contrast to traditional source-channel models. We report the accuracies of two in-house handwritten word recognizers before and after the correction. We achieve highly encouraging results for a large synthetically generated dataset. We also report results for a commercially available OCR on real data.