Abstract-Software Defined Radios (SDR) offer great runtime flexibility both at the physical and MAC layer. This makes them an attractive platform for the development of cognitive radios that can adapt to changes in channel conditions, traffic load, and user requirements. However, to realize this goal, we need a software framework that supports both MAC protocol and PHY layer development in an integrated fashion. In this paper we report on our experience in using two different software frameworks for integrated PHY-MAC development for SDRs: GNU Radio, which was originally designed to support PHY layer development, and Click, a framework for protocol development. We also discuss a number of broader system considerations, such as what functionality should be offloaded to the SDR device.
Green and sustainable chemistry have gained substantial attention worldwide, and the efforts have been greatly appreciated for the substitution of Brønsted acid catalysts from homogeneous to heterogeneous phases. In this perspective, a sulfonic acid-functionalized silica nanospheres (SAFSNS) catalyst was prepared by organosilylation-sulfonation on the surface of well-ordered silica nanospheres as a heterogeneous nanocatalyst. The physicochemical properties of nanocatalyst were well characterized by powder XRD, IR, TGA, DSC, NH 3 -TPD, N 2 sorption, EDAX, and SEM techniques. The attainment of the anchoring of SO 3 H functionalization involving the Brønsted acidities was found up to 0.35 mmol H + /g. The synthesized SAFSNS nanocatalyst ascertain the replacement of the highly toxic liquid phase acids to a stable, solid acid catalyst for the green esterification of carboxylic acids under solvent-free reaction conditions, showed reasonable to excellent esters yield (63-94 %) in 3.5 hours at 100°C with five times reusability without substantial diminution in catalytic proficiency.
Safety Critical Element (SCE) lifecycle management involves identification of Major Accident Hazards (MAHs); selection of the Safety Critical Elements by identifying structures and plant which can cause, contribute to, prevent or help recover from a major accident event; and to develop the performance standards for the identified SCEs. It also involves alignment of maintenance routines, inspection and testing, performance history etc. required to maintain the SCE in a suitable condition. Managing deviations and impacts on management of change also form a part of the lifecycle management of SCEs. The continual monitoring of the status of the hardware barriers and performance assurance tasks enable the operating staff and the management to analyse the ongoing conformance of the SCEs with their performance standards. This provides opportunities for improvement and possibilities for further risk reduction.
The purpose of this paper is to elaborate on the Safety Critical Element (SCE) lifecycle management process for new and existing facilities. It aims to highlight weaknesses in lifecycle management of Safety Critical Elements and helps the reader to identify improvements both in terms of the processes and content of the Performance Standards. It further highlights the benefits of the use of Safety Critical Elements and Performance Standards in achieving overall improvements and risk reduction.
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