by Zhichao Wang  , Daisuke Mori  , Sou Taminato  , Yasuo Takeda  , Osamu Yamamoto  and Nobuyuki Imanishi

Received: 18 November 2025;  Published: 26 February 2026;  doi: 10.21926/jept.2601004

A thin film of PEO18Li(CF3SO2)2N(LiTFSI)-tetraethylene glycol dimethyl ether (G4)-Li1.4Al0.4Ge0.2Ti1.4(PO4)3-LiCl·H2O (LAGTP·LiCl) was prepared by addition of 1,2-dimethoxyethane (DME). The grain boundary resistance of PEO18LiTFSI-LAGTP·LiCl was considerably reduced by the addition of G4, and a large-sized thin film of the composite polymer electrolyte was prepared easily by the addition of 10 wt.% DME. The electrical conductivity of [(PEO18LiTFSI-2G4)-5 wt.% LAGTP·LiCl]-10 wt.% DME was 1.2 × 10-4 S cm-1 at 25°C, a [...]

by Brendan Ifeany Ekwueme  , Ogheneruona Endurance Diemuodeke  , Mohammed Moore Ojapah  and Chidozie Ezekwem

Received: 17 September 2025;  Published: 09 March 2026;  doi: 10.21926/jept.2601005

The work focused on modelling and optimisation of integrated renewable energy conversion technologies based on sunlight, wind, and biomass, with dual energy storage (battery and hydrogen), for Patani Island, Delta State, Nigeria. The study was aimed at satisfying the energy demand of the Patani Island community (5°13’43” N, 6°11’29” E). A mathematical model was developed to describe the integrated system, and a genetic algorithm was employed to optimize the allocation of energy demand, energy generation, and energy [...]

by Walid Mohamed Mahmud

Received: 09 September 2024;  Published: 26 March 2026;  doi: 10.21926/jept.2601006

Electrical submersible pumps (ESPs) are an efficient and reliable artificial lift method for lifting large volumes of fluids from wellbores at flexible rates. Despite their advantages, including high flow rates and real-time downhole telemetry, ESPs are prone to frequent and unforeseen failures under harsh reservoir conditions, resulting in costly production delays and interventions. This paper presents an integrated evaluation of ESP failure mechanisms based on an analysis of run and pull reports, dismantle inspec [...]