A real-time DSP enabled digital subcarrier crossconnect (DSXC) with resampling filters is demonstrated based on distributed arithmetic (DA) for channel frequency translation. This circuit-based DSXC supports flexible and fine data-rate granularity of subcarrier channels, and offers the capability to improve spectral efficiency in optical networks.
Wheelset vibration response of two Transnet locomotive classes i.e. D39 200 and D44 are investigated using the modal analysis method. These two locomotive classes are the only classes used on the Belfast to Steelpoort railway line in the Limpopo Province of South Africa. The class D44 replaced the class D39 200 locomotives over two years ago. Short-pitch rail corrugation exists on rail track curves of the railway line. The axial (lateral) resonance frequencies of wheelsets from both locomotive classes prove to be more, than resonances in any other direction of vibration. This is in good agreement with the previous tests done on a class D39 200 locomotive wheelset. The axle coupling vibration response was measured in the axial direction by exciting one wheel and measuring accelerance of the opposite wheel on the wheelset. Vibration response for the class D44 wheelset shows more lightly damped resonance modes in the axial direction. The characteristics of the axial vibration response being lightly damped with the highest accelerance implies most of the vibration occurs in this direction and may be associated with most rail track damages.
The current work describes the development, construction and experimental investigation of a simple StandingWave Thermo-Acoustic Engine (SWTAE). This work aims at providing additional clarity on the construction and the performance of simple SWTAEs. The proposed SWTAE will be used to drive a traveling wave thermo-acoustic refrigerator, through the generated sound wave and ultimately induce cooling. For experimental purposes, the heat supply used in this experimental study are electric cartridge heaters. This study provides clarity as far as the temperature supplied to the system is concerned. To characterize the acoustic power of the SWTAE, the onset temperature differences across the stack for the engine to start producing sound has been measured. Three different configurations have been investigated and general trends showing the relationship between the supply heat, the generated sound wave and the minimum temperature required to produce a sound wave have been obtained.
The energy usage of space heating (SH) and water heating (WH) processes may account for approximately 60% and 24% of the total energy consumption in residential buildings, respectively. This paper proposes the optimal control of an integrated system for water and space heating at the Central University of Technology student residence. The system consists of solar PV modules, batteries, electrolyser, hydrogen storage vessel, fuel-cell, heat pump and domestic hot water storage. The main aim of this study is to propose a method to reduce the energy cost, by applying optimal control of the integrated system operating under the variable Time of Use tariff. The background on the problem statement, the literature review, aim, objective, methodology as well as expected results of the study will be discussed in the sections below.
A resistive switching memory behavior has been observed in PVA incorporated with Aluminium doped Zinc Oxide (AZO) nano particles drop cast on Alumiuium tape. An ON/OFF ratio of about 4 orders of magnitude encourages and leads to the development of ReRAM memory cell. The conduction mechanisms of different segments before and after switching has indicated a clear change of activation energies involved.
