The following manuscripts will be appeared in September 2023 as vol. 5 , issue no. 1:

Proofread No. 1. Enhanced InP-based Gunn Diodes with Notch-δ-doped Structure for Low-THz Applications

Siti Amiera Mohd Akhbar, Kan Yeep Choo and Duu Sheng Ong*

Faculty of Engineering, Multimedia University, Cyberjaya, Selangor, Malaysia.

*Corresponding author:, ORCiD: 0000-0003-4631-6695, pp. 1 - 4.

Manuscript Received: 8 September 2022, Accepted: 12 October 2022, Published: 15 March 2023

Abstract - In this work, Monte Carlo simulation is performed for InP Gunn diode with a notch-δ-doped structure. It is found that the presence of the δ-doped layer has improved the Gunn diode performance significantly as compared to the conventional notch structure. The d-doped effect caused an increment in the fundamental operating frequency and current harmonic amplitude in InP Gunn diodes by modifying the electric field profile within the device. An InP notch-δ-doped Gunn diode with device length of 800 nm under 3V DC bias is capable of producing AC current signal of 287 GHz, reaching the THz region, with its harmonic amplitude being 5.68×108 A/m2. It is observed that InP-based notch-δ-doped Gunn diode is able to generate signals at a higher operating frequency with a larger output power as compared to that of GaAs due to the higher electron drift velocity and threshold field in InP material.

Keywords— Gunn diode, δ-doped, Monte Carlo model, Indium Phosphide, terahertz source


Proofread No. 2. Feasibility of Use of Second Life Electrical Vehicle Batteries in Data Centres in Malaysia

Abdulla, Mubaah, and Siva Priya Thiagarajah*

Faculty of Engineering, Multimedia University, Cyberjaya, Selangor, Malaysia.

*Corresponding author:, ORCiD: 0000-0002-0024-7279, pp. 5 - 11.

Manuscript Received: 13 September 2022, Accepted: 13 October 2022, Published: 15 March 2023

Abstract – It is estimated that the cumulative of Electric Vehicles (EVs) will reach 85 million by 2030.  EV batteries that have degraded to 80% of their initial capacity no longer provide the required efficiency for EV, resulting in an increasing amount of batteries being discarded and stored in warehouses instead of being recycled. The cost of this storage after its End of Life (EOL) adds to the initial cost of the EV. There is amounting environmental pressure to re-purpose these discarded batteries in other applications, such as energy arbitrage and peak shaving, such that the initial cost of the EV be reduced. This work presents a feasibility study that allows discarded EV batteries to be repurposed batteries to provide peak shaving in a mid-tier data centre with an area size of 465 m2. A comparison of the cost during peak hours shows that the repurposed batteries can be used as a reliable power supply source to reduce the reliance of data centres on grid power during peak hours. Results showed that the use of these repurposed batteries also achieved a higher cost savings as compared to using brand new Lithium Ion battery over a period of 10 years. A reliability study also shows that the repurposed battery system and brand new battery system performs at par, when the data centre draws power from the grid during peak hours. The study concludes that power supply system in data centres that uses repurposed batteries to achieve peak shaving is a cost effective, green solution that should be implemented. In the larger picture, the reusability of the EV batteries is expected to reduce the initial price of the EV cars, allowing a larger market penetration and thus ensuring the sustainability of the EV car industry. Reusing the stored batteries also reduces environmental issues related to Lithium mining for brand new batteries, such as mining pollution and fresh water shortage.

Keywords— Peak power shaving, repurposed lithium ion batteries, operation cost reduction, environmental damage reduction,  electrical vehicle industry sustainability