TY - JOUR TI - The role of hybrid nanofluids in optimizing parabolic trough concentrator performance: A comprehensive review AU - GUPTA, S.K. AU - KUMARI, S. JO - Sigma Journal of Engineering and Natural Sciences PY - 2026 VL - 44 SP - 698 EP - 719 DO - 10.14744/sigma.2026.2022 ER -