03830cas a2200409 a 4500 20260818084448.0 110908s1982 th uu|m rtt 0| a1eng d .b10154723 AIT Thesis no. AE-82-03 Onrawee Techasena Compression tests for measuring the firmness of potatoes Bangkok : Asian Institute of Technology, 1982 63 p. Thesis ; no. AE-82-03 A thesis submitted in partial fulfilment of the requirement for the degree of Master of Science, School of Environment, Resources and Development Thesis (M.Sc.) - Asian Institute of Technology, 1982 The firmness of potatoes was evaluated in terms of the elasticity modulus based on axial compression, radial compression and Hertz contact stress analysis using an Instron testing machine. Cylindrical test specimens (1. 5 cm in diameter and 3. 0 cm long), whole potatoes and their flat surface were tested under compression at the loading rate of 50mm/min. The changes in firmness of potatoes were monitored over a period of 8 weeks when stored at 5, 10, 20 and 30°C. Potatoes exhibited nonlinear force-deformation behavior in axial compression tests requiring the calculation of tangent elasticity modulus values as a function of percent compression. In .radial compression tests, there was marked deviation of experimental force-deformation relationships from the theory. Therefore, the computed values of elasticity modulus were expressed as a function of percent compression. In compression tests with whole potatoes and their flat surface, the force-deformation relationship conformed to Hertz analysis only at low compression values and could be used to calculate elasticity modulus independent of percent compression. The experimental elasticity modulus values showed a wide variation in their magnitudes primarily .due to the characteristics of each test method used. The firmness of potatoes appeared to decrease exponentially with storage period at all temperatures. Since the elasticity modulus values .as determined in various compression tests were different, it was necessary to express change in their magnitude during storage on percentage basis for making relative comparisons. The radial compression test showed maximum percentage decrease in the elasticity modulus values with storage time. The axial compression test values were next. The compression of whole potatoes and their flat surface followed very closely to each other and showed minimum decrease in the elasticity modulus values during the storage at all temperature. Potatoes Thailand Testing Jindal, Vinod Kumar, Chairperson Yudhbir, Examination Committee Kim, Kong-Hwan, Examination Committee The US-ASEAN, Scholarship Donor Asian Institute of Technology. Thesis ; no. AE-82-03 Full-Text http://203.159.5.9/ait-thesis/detail.php?q=B21126 .b10154723 mnait x 240821 2 951012 m a x 0 mnait mnait mnarc 20 40 Barcode : 30050003029336 CREATED : 1994-05-16 RECORD # : i10182767 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 Barcode : 30050003029369 CREATED : 1994-05-16 RECORD # : i10182779 LPATRON : 1017416 LCHKIN : 2005-05-14 # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 3 TOT RENEW : 4 Barcode : 30050120301857 CREATED : 2016-05-26 RECORD # : i12994455 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 20565 20565 0 0 0 0 MAIN MAIN mnait 2026-08-18 0 AIT Thesis no. AE-82-03 30050003029336 2026-08-18 08:44:48 1 2026-08-18 20 0 0 0 0 MAIN MAIN mnait 2026-08-18 0 AIT Thesis no. AE-82-03 30050003029369 2026-08-18 08:44:48 2 2026-08-18 20 0 0 0 0 MAIN MAIN mnarc 2026-08-18 0 AIT Thesis no. AE-82-03 30050120301857 2026-08-18 08:44:48 2026-08-18 40