Influence of equal channel angular pressing in an acute angle die with a back pressure notch on grain refinement,torsion and mechanical properties of aluminium

Severe plastic deformation improves the strength of a metal by strain hardening. Of the various severe plastic deformation processes, equal channel angular pressing proves to be the right candidate for bulk metal processing. Extensive works were carried out on equal channel angular pressing with channel angle ranging from 90° to 120 ° with or without back pressure on the exit channel. Numerical analyses suggest that reducing the channel angle below 90° would enhance the magnitude of strain imparted and, with prediction of a lesser strain homogeneity in such cases. Hence an acute angled equal channel angular pressing die with a back‐pressure notch sunken into the roof of the exit channel was designed, fabricated and was used for processing pure aluminium. Various mechanical properties of the processed materials were tested and acute angle processing imparted superior tensile strength to the work pieces in a single pass that would require several passes in a conventional equal channel angular pressing die. Substantial improvement in grain refinement and torsional properties was identified.     

Detection of cross-channel anomalies

The data deluge has created a great challenge for data mining applications wherein the rare topics of interest are often buried in the flood of major headlines. We identify and formulate a novel problem: cross-channel anomaly detection from multiple data channels. Cross-channel anomalies are common among the individual channel anomalies and are often portent of significant events. Central to this new problem is a development of theoretical foundation and methodology. Using the spectral approach, we propose a two-stage detection method: anomaly detection at a single-channel level, followed by the detection of cross-channel anomalies from the amalgamation of single-channel anomalies. We also derive the extension of the proposed detection method to an online settings, which automatically adapts to changes in the data over time at low computational complexity using incremental algorithms. Our mathematical analysis shows that our method is likely to reduce the false alarm rate by establishing theoretical results on the reduction of an impurity index. We demonstrate our method in two applications: document understanding with multiple text corpora and detection of repeated anomalies in large-scale video surveillance. The experimental results consistently demonstrate the superior performance of our method compared with related state-of-art methods, including the one-class SVM and principal component pursuit. In addition, our framework can be deployed in a decentralized manner, lending itself for large-scale data stream analysis.     

Correlation between central receiver size and solar field using flat heliostats

In Central Receiver Systems (CRSs), thousands of heliostats track the sunrays and reflect beam radiation on to a receiver surface. The size of the reflected image and the extent of reflection from the heliostats are one of the important criteria that need to be taken into account while designing a receiver, since spillage losses may vary from 2 to 16% of the total losses. The present study aims to determine the size of an external cylindrical receiver, such that the rays reflected from all the heliostats in the field are intercepted. A dimensionless correlation with respect to tower height and receiver size (diameter and height) as a function of heliostat size and its position is discussed in the paper. This correlation could be used as a first-order approximation to estimate the receiver dimensions. When applied to the Ivanpah Solar Electricity Generating Station (ISEGS) plant, the correlation yields satisfactory estimation of receiver dimensions.     

Alternative search techniques for face detection using location estimation and binary features

The sliding window approach is the most widely used technique to detect an object from an image. In the past few years, classifiers have been improved in many ways to increase the scanning speed. Apart from the classifier design (such as the cascade), the scanning speed also depends on a number of different factors (such as the grid spacing, and the scale at which the image is searched). When the scanning grid spacing is larger than the tolerance of the trained classifier it suffers from low detections. In this paper, we present a technique to reduce the number of missed detections when fewer subwindows are processed in the sliding window approach for face detection. This is achieved by using a small patch to predict the location of the face within a local search area. We use simple binary features and a decision tree for location estimation as it proved to be efficient for our application. We also show that by using a simple interest point detector based on quantized gradient orientation, as the front-end to the proposed location estimation technique, we can further improve the performance. Experimental evaluation on several face databases show better detection rate and speed with our proposed approach when fewer number of subwindows are processed compared to the standard scanning technique.     

Test methods for characterizing concrete properties at elevated temperature

Fire resistance of structural members is dependent on the thermal and mechanical properties of constituent materials and these properties vary as a function of temperature. Currently, there are limited standardized test procedures for evaluating thermal and mechanical properties of construction materials at elevated temperatures. This paper provides a review and assessment of test methods and procedures for evaluating high temperature thermal and mechanical properties of concrete. The drawbacks and variations in currently available test procedures and methods in standards are discussed. Recommendations on the most suitable methods and procedures for measuring thermal and mechanical properties at elevated temperature is presented. In addition, applicability of the proposed high temperature test methods and procedures is illustrated through a case study on conventional concrete specimens. Further, the need for developing standards by organizations such as American Society for Testing and Materials (ASTM), with standardized specifications and test procedures for measuring high temperature properties of construction materials, is laid out.     

Understanding e‐Government portal use in rural India: role of demographic and personality characteristics

Electronic government (e‐Government) is one of the most important ways to bridge the digital divide in developing countries. We develop a model of e‐Government portal use. We use various individual characteristics, namely demographics and personality, as predictors of e‐Government portal use. Specifically, our predictors were (1) gender, age, income and education; (2) the Big Five personality characteristics, i.e. extraversion, neuroticism, conscientiousness, agreeableness and openness to experience; and (3) personal innovativeness with information technology. We conducted a field study in a village in India. We collected data from over 300 heads of household. We found support for our model, with most variables being significant and explaining 40% of the variance in e‐Government portal use.     

Improved analysis of sinigrin in Ethiopian mustard

An ion‐pair reversed‐phase high‐performance liquid chromatography (HPLC) method was developed for the analysis of sinigrin in Ethiopian mustard (Brassica carinata A. Braun) seed and seed fractions. Separation was compared on several RP‐HPLC columns (Inertsil^® ODS‐4 C₁₈ and ZORBAX^® Eclipse XDB‐C₁₈) with an isocratic eluent containing 100% aqueous (aq.) tetramethylammonium bromide (10 mm , pH 5.0). Sinigrin retention was affected by HPLC variables including the type of ion‐pair reagent, buffer strength and pH, acetonitrile concentration, column temperature and eluent flow rate. Partial validation demonstrated this optimised chromatographic condition to be linear, accurate and precise. Multistage extraction using 70% (v/v) aq. methanol was more efficient than 50% (v/v) aq. acetonitrile. In addition, the matrix effect and recovery rate as well as processing efficiency of the analytical protocol were determined. This method is suitable for high throughput analysis of sinigrin in Ethiopian mustard seed and seed fractions.