Search

This paper analyses the effects of a non-uniform laminar flow past a circular cylinder using the direct numerical simulation approach. Compared to the cylinder immersed in a uniform flow case, modifications caused by the non-uniform approaching flow on the evolution of the flow and sound fields are studied in detail in the present work. The prescribed non-uniform velocity profile at the inlet has a Gaussian distribution and imitates a jet or a wake flow velocity profile. The sound is generated due to periodic vortex shedding behind the circular cylinder. The frequency of vortex shedding and the strength of the shed vortices depend on the inflow velocity profile. Hence, variation of the inflow velocity profile alters the shed vortices, changing the generated sound field. It is observed that the amount of gain or deficit present in the prescribed inflow velocity profile compared to the uniform inflow profile alters the sound field information. The jet kind of inflow profile creates a sound of higher frequency and intensity in contrast to the wake kind of inflow profile. The presence of shear in the inflow velocity profile is also expected to change the sound propagation direction. However, in present simulations, the distance over which sound propagation is considered is small compared to the wavelength of the sound waves, and sound beam drift effects are not observed much. [ABSTRACT FROM AUTHOR]

Due to the intelligent, adaptive nature of various operations and their ability to provide maximum comfort to the occupants residing in them, smart buildings are becoming a pioneering area of research. Since these architectures leverage the Internet of Things (IoT), there is a need for monitoring different operations (occupancy, humidity etc.) to provide sustainable comfort to the occupants. This work proposes a novel approach for intelligent building operations monitoring using rule-based complex event processing (CEP) and query-based approaches for dynamically monitoring the operations. Siddhi is a CEP engine designed for handling multiple sources of events data in real time and processing it according to predefined rules using a decision tree. Since datastream is dynamic in nature, to keep track of different operations, we have converted the IoT data into an RDF (Resource Description Framework) dataset. The RDF dataset is ingested to Apache Kafka for streaming and for stored data we have used GraphDB tool that extracts information with the help of SPARQL query. Additionally, a large number of events are passed through CEP for correlating and analyzing events in real time, and we measure the performance of CEP engines through SPARQL for enhancing decision support. The proposed approach is evaluated by deploying rules to events through the CEP engine and assessing their processing efficiency in terms of time. Subsequently, a risk estimation scenario is proposed to generate alerts for end users if any smart building operations need immediate attention. However, the proposed work has limitations regarding adaptive and standard parameters, which may cause the rules to fail in adapting to changing data streams. [ABSTRACT FROM AUTHOR]

The work reported in this paper describes the design and simulation of a novel current mirror readout circuit based MOSFET integrated cantilever structure for micro-gram (μ g) mass sensing applications. The proposed mass sensing structure consist of silicon cantilever as the micromechanical structure, MOSFET as strain sensing element and current mirror as a readout circuit. In this paper, studies have been carried out on three structures (a) n-channel MOSFET based resistive loaded current mirror integrated cantilever mass sensor (b) p-channel MOSFET based resistive loaded current mirror integrated cantilever mass sensor and (c) n- and p- channel MOSFETs based dual current mirror integrated cantilever mass sensor. The input MOSFET(s) of the current mirror acts as the reference transistor(s) while the output MOSFET(s) of the mirror circuit acts as strain sensing element(s) to measure the cantilever deflection under externally applied load. The structural and the electrical characteristics of the sensors were simulated using COMSOL Multiphysics and TSPICE software respectively. Simulation results showed a sensitivity of 21.89 μ V/ μ g, 1 μ V/ μ g and 115.57 μ V/ μ g for nMOS, pMOS and dual channel cantilever mass sensor. The fabrication steps and mask layout of the proposed sensor have also been presented in this paper. The novelty of this work is emphasized by the innovative integration of a CMOS current mirror circuit with a cantilever for mass sensing. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "A conceptual study on novel current mirror integrated cantilever (CMIC) mass sensor for micro-gram (µg) range sensing applications" published in the journal Microsystems Technologies. The correction addresses an error in the affiliation of two authors, providing the correct affiliations for Kalpana Gogoi and Shashi Kumar. The original article has been corrected. The publisher, Springer Nature, remains neutral regarding jurisdictional claims and institutional affiliations. [Extracted from the article]