Solar energy-based extraction of essential oils from cloves, cinnamon, orange, lemon, eucalyptus, and cardamom: a clean energy technology for green extraction by Al-Hilphy, Asaad Rehman, K. Ahmed, Abdul Hadi, Gavahian, Mohsen, Chen, Ho Hsien, Chemat, Farid, Al-Behadli, Thamer-K.M., Mohd Nor, Mohd Zuhair, Ahmad, So'bah