ABSTRACT
PVDF was prepared by compression molding, and its phase content/structure was assessed by WAXD, DSC, and FTIR-ATR spectroscopy. Next, PVDF samples were aged in bioethanol fuel at 60 °C or annealed in the same temperature by 30 â 180 days. Then, the influence of aging/annealing on thermal stability, thermal degradation kinetics, and lifetime of the PVDF was investigated by thermogravimetric analysis (TGA/DTG), as well as the structure was again examined. The crystallinity of ~41% (from WAXD) or ~49% (from DSC) were identified for unaged PVDF, without significant changes after aging or annealing. This PVDF presented not only one phase, but a mixture of α-, ß- and γ-phases, α- and ß-phases with more highlighted vibrational bands. Thermal degradation kinetics was evaluated using the non-isothermal Ozawa-Flynn-Wall method. The activation energy (E a ) of thermal degradation was calculated for conversion levels of α = 5 â 50% at constant heating rates (5, 10, 20, and 40 °C minâ1), α = 10% was fixed for lifetime estimation. The results indicated that temperature alone does not affect the material, but its combination with bioethanol reduced the onset temperature and E a of primary thermal degradation. Additionally, the material lifetime decreased until about five decades (T f = 25 °C and 90 days of exposition) due to the fluid effect after aging.
ABSTRACT
Decommissioning offshore Floating Production, Storage and Offloading (FPSO) platforms requires extensive technical knowledge, since it generates different post-consumer materials, including mooring lines. These ropes are made from polyester high tenacity yarn, based on polyethylene terephthalate (PET), and their high added value means they should not be discarded as scrap. This paper aims to present a review and technical opportunities, from an economic standpoint, of recycling the mooring lines recovered from decommissioned FPSOs. Studies conducted over the last two years have researched and developed different potential applications for the fibers. These studies include collaborative project initiatives involving technical and management professionals, universities and private enterprises, with a view to achieving a more sustainable destination for these fibers.
Subject(s)
Polyesters/chemistry , Recycling/economics , Ships/instrumentation , Ships/economicsABSTRACT
Poly(vinilidene fluoride) was characterized before and after stress relaxation by tensile tests and time-domain nuclear magnetic resonance (TD-NMR). Tensile tests were performed to provide mechanical properties, focused on the data of elastic modulus for this matter. The TD-NMR technique was used to calculate the fraction of crystalline, constrained amorphous and free amorphous phase, and the transversal relaxation time of each of these phases.
ABSTRACT
OBJECTIVE: The purpose of this study was to investigate the effects of phototherapy on delayed onset muscle soreness (DOMS) as measured using the Visual Analog Scale (VAS), McGill Pain Questionnaire, Resting Angle (RANG), and girth measurements. BACKGROUND DATA: Previous research has failed to prove the beneficial effects of phototherapy on DOMS. METHODS: This was a randomized double-blind controlled study with 27 subjects (18-35 years) assigned to one of three groups. The experimental group received 8 J/cm2 of phototherapy each day for five consecutive days using super luminous diodes with wavelengths of 880 and visible diodes of 660 nm at three standardized sites over the musculotendinous junction of the bicep. The sham group received identical treatment from a dummy cluster. The controls did not receive treatment. The study was completed over five consecutive days: on day one baseline measurements of RANG and upper arm girths were recorded prior to DOMS induction. On days 2-5, RANG, girth, and pain were assessed using VAS and the McGill Pain Questionnaire. RESULTS: The experimental group exhibited a significant decrease in pain associated with DOMS compared to the control (p=0.01) and sham groups (p=0.03) based upon the VAS at the 48-h period. The McGill Pain Questionnaire showed a significant difference in pain scores at the 48-h period between the experimental and the sham groups (p=0.01). There were no significant differences day to day and between the groups with respect to girth and RANG. CONCLUSION: The results of this study provide scientific evidence that phototherapy as used in this study provides a beneficial effect to patients who may experience DOMS after a novel exercise session.
