Finite element analysis and analytical simulations of Suspended Gate-FET for ultra-low power inverters

This paper proposes, the investigation of the Suspended Gate Field-Effect Transistor (SG-FET) small-slope switch based on a hybrid numerical simulation approach combining ANSYS^TM Multiphysics and ISE-DESSIS^TM in a self-consistent system. The proposed numerical simulations uniquely enable the investigation of the behavior and the physics of complex micro-electro-mechanical/solid-state devices, such as the SG-FET. Abrupt switching as well as the effect of trapped charges in the gate dielectric are demonstrated. The numerical data serve to calibrate an analytical EKV-based SG-FET model, which is then used to design and originally simulate a sub-micron (90 nm) scaled SG-FET complementary inverter. It is shown that, due to abrupt switching in the subthreshold region and electro-mechanical hysteresis, the SG-FET inverter could deliver a significant power saving (1–2 decades reduction of inverter peak current and practically no leakage power) compared to traditional CMOS inverter.     

Scarce-resource capacity sharing in cognitive radio environments: a new game theoretical model

This paper proposes a novel model of the input impedance of a circular-loop antenna based on wave equations. A circular-loop antenna is equivalent to uniform parallel double wires with losses and a short circuit load. The characteristic impedance, the propagation coefficient and the inductance, capacitance and resistance per unit length of the uniform parallel double wires with losses can first be expressed as closed solutions, and the mathematical model of the input impedance of the circular-loop antenna can then be derived naturally from the wave equations. Comparison of the data curve from this model with curves from simulations and experiments show that they are similar; however, some discrepancies are observed, and are attributed to the estimation error of the radiation resistance of the circular-loop antenna. As long as the circular-loop antenna is made from an isotropic material and its size remains uniform, the equivalent method is valid electrically for both small- and large-sized circular-loop antennas.     

Battery state of health estimation: a structured review of models,methods and commercial devices

Estimating the dynamic status parameters of a battery, such as its state of health (SoH) and remaining useful life (RUL), is still a very difficult and complex task. In this paper we perform a structured review of the most relevant state of the art models, algorithms and commercial devices employed in the estimation of the SoH/RUL battery performance figures, in the context of embedded applications. The models and estimation techniques are thoroughly classified and, for each taxonomy class, a presentation of the working principles is made. A comprehensive set of metrics is then introduced for the evaluation of the SoH/RUL estimation techniques from the perspective of their implementation and operation efficiency in embedded systems. These algorithms are then analyzed and discussed in a comparative manner, with concrete figures and results. The capability and the performance of the different types of off‐the‐shelf fuel gauges to estimate the battery SoH/RUL parameters are also evaluated in this paper. Copyright © 2016 John Wiley & Sons, Ltd.     

TREC chemical information retrieval - An initial evaluation effort for chemical IR systems

There is little need to emphasize the importance of chemoinformatics and chemical information retrieval. However, what seems to require a lot more effort in convincing members of the community is the need for standardized evaluation procedures and measures. How confident are we, as users, that the search tools we used have given us all the information that we were looking for? It is unrealistic to believe a marketing campaign which claims that a specific patent IR (information retrieval) system can find all relevant results for a search topic. And if we don’t trust marketing campaigns, how can we get an idea of what to expect from a patent search engine?One of the most prominent initiatives to work in this direction, of evaluating chemical IR tools, has started in 2009 with the support of NIST (National Institute for Standards and Technology): the TREC Chemical IR Track focuses on evaluation of search technologies for retrieval and knowledge discovery of digitally stored information on chemical patents and academic journal articles on chemistry. This paper describes our 2009 experience, presents the official results of the participating groups, and lays down the targets for 2010.     

Step Transductor for PM Hybrid Stepping Motor

ABSTRACT

In this paper an original implementation of the step transductor for PM hybrid stepping motor is presented. This implementation is based upon the measurement of the back emf voltage. The difficulties which arise are not due ananalogical circuits (with OP-AMP), but to the switching noises (spikes) found in the back emf voltage which has been measured. Tnise spikes have eliminated by means of some timer circuits. With this structure, the detent position sensing of the phases with an error less than 5% could be obtained. To decrease the number of IC's used, some timing functions can be implemented in software on a microcomputer-on-a-chip (e.g. 8746). The same microcomputer can be used also as a controller for the closed-loop stepping motor system.     

Performance of heavy ductile iron castings for windmills

The main objective of the present paper is to review the specific characteristics and performance obtaining conditions of heavy ductile iron (DI) castings, typically applied in windmills industry, such as hubs and rotor housings. The requirements for high impact properties in DI at low temperatures are part of the EN- GJS-400-18U-LT (SRN 1563) commonly referred to as GGG 40.3 (DIN 1693). Peaditic influence factor (Px) andantinodularising action factor (K1) were found to have an important influence on the structure and mechanical properties, as did Mn and P content, rare earth (RE) addition and inoculation power. The presence of high purity pig iron in the charge is extremely beneficial, not only to control the complex factors Px and K1, but also to improve the 'metallurgical quality' of the iron melt. A correlation of C and Si limits with section modulus is very important to limit graphite nodule flotation. Chunky and surface-degenerated graphite are the most controlled graphite morphologies in windmills castings. The paper concluded on the optimum iron chemistry and melting procedure, Mg-alloys and inoculants peculiar systems, as well as on the practical solutions to limit graphite degeneration and to ensure castings of the highest integrity, typically for this field.     

PolyCAFe—automatic support for the polyphonic analysis of CSCL chats

Chat conversations and other types of online communication environments are widely used within CSCL educational scenarios. However, there is a lack of theoretical and methodological background for the analysis of collaboration. Manual assessing of non-moderated chat discussions is difficult and time-consuming, having as a consequence that learning scenarios have not been widely adopted, neither in formal education nor in informal learning contexts. An analysis method of collaboration and individual participation is needed. Moreover, computer-support tools for the analysis and assessment of these conversations are required. In this paper, we start from the “polyphonic framework” as a theoretical foundation suitable for the analysis of textual and even gestural interactions within collaborative groups. This framework exploits the notions of dialogism, inter-animation and polyphony for assessing interactions between participants. The basics of the polyphonic framework are discussed and a systematic presentation of the polyphonic analysis method is included. Then, we present the PolyCAFe system, which provides tools that support the polyphonic analysis of chat conversations and online discussion forums of small groups of learners. Natural Language Processing (NLP) is used in order to identify topics, semantic similarities and links between utterances. The detected links are then used to build a graph of utterances, which forms the central element for the polyphonic analysis and for providing automatic feedback and support to both tutors and learners. Social Network Analysis is used for computing quantitative measures for the interactions between participants. Two evaluation experiments have been undertaken with PolyCAFe. Learners find the system useful and efficient. In addition to these advantages, tutors reflecting on the conversation can provide quicker manual feedback.     

INFRARED TRANSIENT THERMOGRAPHY FOR NON-CONTACT,NONDESTRUCTIVE INSPECTION OF WHOLE AND DISSECTED APPLES AND OF CHERRY TOMATOES AT DIFFERENT MATURITY STAGES

Introduction

Fruits and vegetables used in various processed products, as well as in fresh market sales, are expected to comply with the certain quality standards. However. quality is everything but a single parameter state and, therefore, a variety of subjective and objective measurements are usually performed. In particular, the firmness and maturity are considered important attributes to the quality of fruits and vegetable crops. Presently. these parameters are usually determined either destructively (by a pressure tester) or by means of ultrasound; a development of alternative methods has been strongly encouraged in the recent years.     

Investigations of the unsteady diffusion process in microchannels

This paper is concerned with the investigations and modeling of the unsteady diffusion process along a straight micro-channel with a cross section of 380 μm×360 μm. The studied process is characterized by small Reynolds numbers (Re<10) and high Péclet number (Pe>1000). The 3D computations of the coupled momentum and diffusion equations for isochoric motions are performed with the FLUENT code using the unsteady solvers for both equations. In the limit of stationary solutions, the numerical results are validated by direct flow visualizations and experimental data using confocal microscopy. The computed distributions of concentration provide qualitative and quantitative information on the transitory diffusion process and the rate of solute spreading within the investigated geometry. In particular, the pattern of the “butterfly effect” is represented and analyzed during the non-stationary dynamical process. The work is relevant for the design of novel microfluidics applications where the control of diffusion processes at the walls are important (absorption, extraction, capture of molecules or nano-particles).