Enhanced Machinability of Silicon Carbide via Microstructural Design

The machinability of a heterogeneous silicon carbide with weak interphase boundaries, elongated grains, and high internal stresses is evaluated relative to a homogeneous control material with a well-bonded, equiaxed, and unstressed grain structure. Drilling and grinding rates for the silicon carbide are substantially enhanced by the microstructural heterogeneity—the weak boundaries enable easy grain-scale dislodgement in place of the more conventional macrofracture chipping mode of removal. At the same time, the residual machining damage in the machined surfaces is significantly less strength degrading in the heterogeneous material. Implications concerning the microstructural design of flaw-tolerant ceramics for enhanced machinability are considered.     

Ca2+ ⇌ Pb2+ exchange reaction of calcium silicate hydrate: Ca5Si6O18H2 · 4H2O

Recently it has been demonstrated that synthetic calcium silicate hydrate Ca₅Si₆O₁₈H₂ · 4H₂O shows cation exchange properties. In this paper we give the mass balance and thermodynamic data of the Ca²⁺ Pb²⁺ exchange which occurs in 1.1 nm tobermorite when placed in dilute Pb²⁺ solutions. The solid and solution phases have been analysed. The free energy of the exchange reaction at room temperature has been calculated. The X-ray powder diffraction data of the exchanged product have been reported. The crystallinity of the exchanger remains intact after ion exchange.     

Aware Community Portals: Shared Information Appliances for Transitional Spaces

People wish to maintain a level of awareness of timely information, including presence of others in the workplace and other social settings. We believe this provides better exchange, coordination and contact within a community, especially as people work in asynchronous times and distributed locations. The challenge is to develop lightweight techniques for awareness, interaction and communication using shared information appliances. In this paper, we describe the design of an exploratory responsive display projected within a shared workspace at the MIT Media Lab. The system uses visual sensing to provide relevant information and constructs traces of people’s activity over time. Such aware portals may be deployed in casual workplace domains, distributed workgroups, and everyday public spaces.     

Diagnosis of bearing defects using tunable Q-wavelet transform

Defects in rolling element bearings are foremost cause of failure in rotating machines. The accurate and fast diagnosis of bearing defects like spall, dents, pits, cracks etc. on the various component of bearing can be accomplished by analysis of vibration signals using various advanced signal processing techniques. In this work, a new technique for the diagnosis of bearing defects using tunable Q-wavelet transform and fractal based features has been presented. The vibration signals have been recorded experimentally. These signals are decomposed into a number of sub-bands using tunable Q-wavelet transform for effective feature extraction. Classical statistical features and fractal dimension based features such as Higuchi fractal dimensions and Katz fractal dimensions are computed for each decomposed sub-band. These features obtained using tunable Q-wavelet transform of vibration signal are having better capability to classify defects through various machine learning algorithms.     

Steady-State Reactive Distillation Simulation Using the Naphtali-Sandholm Method

The steady-state simulation of reactive distillation columns using the conventional Naphtali-Sandholm (NS) method is studied. Results for methyl acetate and MTBE columns show that the method effectively solves the highly non-linear MEH equations. In the MTBE system, three distinct steady states are obtained as the Newton step factor is decreased from high to low values. The versatility of the method in handling different column specifications and its application for preliminary control studies is also demonstrated. A novel feature of the work is the inclusion of reaction conversion as a possible column specification. The specification of reaction conversion and product purity provides a direct means for obtaining operating conditions for high purity and high conversion column operation.     

Object oriented framework for real-time image processing on GPU

General purpose computation on graphics processing unit (GPGPU) provides a significant gain in terms of the processing time compared with CPU. Images are particularly good subjects for massive parallel implementations on GPU. Thus, the processing time can be improved for computer vision and image/video processing algorithms. However, GPGPU has a fairly complex integration process in a framework and they evolve very rapidly. In this paper, we present a framework that provides all the desired primitives related to GPGPU-based image processing algorithms, which makes it easy and straightforward for the user to exploit. The proposed framework is object-oriented, and it utilizes design patterns. The user can benefit from all the advantages of object-oriented programming, such as code reusability/extensibility, flexibility, information hiding, and complexity hiding. This makes it possible to rapidly integrate new technologies and functionality as they appear.     

Eyeing the web interface: the influence of price,product, and personal involvement

Although Internet retailing has become part of mainstream commerce, there is still lack of research related to web interface design as a function of product price, product complexity, and personal involvement of consumer with the product. Different types of products require different aspects of information and environment as demanded by consumers; thus, it is imperative for retailers to appropriately tailor their online presentation of products. Drawing from the elaboration likelihood model and media richness theory, we investigate the effectiveness of peripheral cue-dominated interfaces, balanced cue-dominated interfaces, and central cue-dominated interfaces on consumer purchase intention. Nearly 1000 subjects participated in this study over a period of 2 years. Our analyses provide support for the contention that the role of website cues (peripheral and central) on the consumer varies by the type of product. Our findings have implications for research and practice.     

BitTorrent-like P2P approaches for VoD: A comparative study

The enormous popularity of Video on Demand (VoD) has attracted substantial research attention into the effective use of peer-to-peer (P2P) architectures to provide solutions at large-scale. In particular, the high efficiency of BitTorrent has inspired many P2P protocols for VoD. However, these protocols use different approaches to adapt the design of Bittorrent to VoD, and in most cases their performance has been evaluated separately and in limited scenarios. As a consequence, the research community still lacks a clear understanding of how these protocols compare against each other and how well each of them would work in real world conditions, where, for instance, peers have heterogeneous bandwidths, may freeride or may be located behind NAT/firewall.In this paper, we propose a simulation based methodology which aims at putting forward a common base for comparing the performance of these different protocols under a wide range of conditions. We show that, despite their considerable differences: (i) existing BitTorrent-like VoD approaches all share some characteristics, such as that their bandwidth reciprocity based methods to incentivize cooperation do not always yield an optimal overall performance. Furthermore, we demonstrate that (ii) in these protocols there is a trade-off between QoS and resilience to freeriding and malicious attacks. We also discover that, (iii) when peers doing streaming coexist with peers doing traditional file transfer, the latter actually benefit from this coexistence, at the expenses of the former. Finally, we show that (iv) early departures of peers from the system do not significantly affect the QoS delivered, while jumping to a different position in the file has a bigger negative impact. Overall, our findings provide important implications for both VoD service providers and future system designers. On the one hand, our results can guide VoD service providers in selecting the most appropriate protocol for a given environment. On the other hand, exposing the flaws of current approaches will help researchers in improving them and/or designing better ones.     

Designing a Fault-tolerant Fully-Chained Combining Switches Multi-stage Interconnection Network with Disjoint Paths

Multi-stage Interconnection Networks (MINs) are designed to achieve fault-tolerance and collision solving by providing a set of disjoint paths. Ching-Wen Chen and Chung-Ping Chung had proposed a fault-tolerant network called Combining Switches Multi-stage Interconnection Network (CSMIN) and an inaccurate algorithm that provided two correct disjoint paths only for some source-destination pairs. This paper provides a more comprehensive and accurate algorithm that always generate correct routing-tags for two disjoint paths for every source-destination pair in the CSMIN. The 1-fault tolerant CSMIN causes the two disjoint paths to have regular distances at each stage. Moreover, our algorithm backtracks a packet to the previous stage and takes the other disjoint path in the event of a fault or a collision in the network. Furthermore, to eliminate the backtracking penalties of CSMIN, we propose a new design called Fault-tolerant Fully-Chained Combining Switches Multi-stage Interconnection Network (FCSMIN). It has similar characteristics of 1-fault tolerance and two disjoint paths between any source-destination pair, but it can tolerate only one link or switch fault at each stage without backtracking. Our simulation and comparative analysis result shows that FCSMIN has added advantages of destination-tag routing, lower hardware costs, strong reroutability, lower preprocessing overhead, and higher fault-tolerance power in comparison to CSMIN.