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Recovery Properties (recovery + property)

Distribution by Scientific Domains

Polymers and Materials Science	71%

Selected Abstracts

A Novel Fe-Mn-Si Shape Memory Alloy With Improved Shape Recovery Properties by VC Precipitation

ADVANCED ENGINEERING MATERIALS, Issue 1-2 2009
Zhizhong Dong
In this work, a nominally new Fe-Mn-Si based shape memory alloy with a small amount of VC was designed. After an optimized thermo-mechanical treatment, a shape recovery of more than 90% after an elongation of 4% could be achieved when the alloys were heated up to 225°C. In addition, high recovery stresses of up to 380 MPa could be obtained after heating to 225°C, whereas 330 MPa were obtained after heating to 160°C. [source]

Cast NiTi Shape-Memory Alloys,

ADVANCED ENGINEERING MATERIALS, Issue 6 2005
M. Ortega
The purpose of this study is to build a fundamental understanding of the relationship between the structure and properties of cast nickel-titanium (NiTi). The structure of the cast material will be analyzed at various scales and will be related to the properties of the cast material such as transformation temperatures, stress-strain behavior, and recovery properties. This study demonstrates that cast NiTi can possess excellent shape-memory properties. [source]

Strain-Controlled Tensile Deformation Behavior and Relaxation Properties of Isotactic Poly(1-butene) and Its Ethylene Copolymers

MACROMOLECULAR SYMPOSIA, Issue 1 2004
Mahmoud Al-Hussein
Abstract The tensile deformation behaviour of poly(1-butene) and two of its ethylene copoloymers was studied at room temperature. This was done by investigating true stress-strain curves at constant strain rates, elastic recovery and stress relaxation properties and in-situ WAXS patterns during the deformation process. As for a series of semicrystalline polymers in previous studies, a strain-controlled deformation behaviour was found. The differential compliance, the recovery properties and the stress relaxation curves changed simultaneously at well-defined points. The strains at which these points occurred along the true stress-strain remained constant for the different samples despite their different percentage crystallinities. The well-defined way in which the different samples respond to external stresses complies with the granular substructure of the crystalline lamellae in a semicrystalline polymer. [source]

Comparison of recovery properties of desflurane and sevoflurane according to gender differences

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 2 2005
E. Tercan
Background:, The aim of this study was to investigate the recovery properties of desflurane and sevoflurane in patients undergoing elective surgery, according to the gender differences. Methods:, In the study, 160 ASA class I,II patients aged between 20 and 60 years were included. The patients were assigned into two groups according to their gender, and these groups were randomly divided into two groups according to a selected volatile anaesthetic agent. Intraoperative bispectral index, time of postoperative achievement for end-tidal concentrations of volatile agents to decline 50% (ET-AA%50), time for extubation, time for eye opening and orientation, and time for bispectral index values to reach control values were recorded. Aldrete scores and error points of a delayed memory recall test were determined. Results:, Desflurane groups had a shorter ET-AA%50 time, extubation and eye-opening time in male and female patients compared to the sevoflurane groups, and these results were statistically significant (P < 0.05). In both the desflurane and sevoflurane groups, ET-AA%50 time, extubation and eye-opening time were shorter in male patients than in female patients, and these results were also statistically significant (P < 0.05). There were no significant differences among the groups in terms of Aldrete scores and error points of delayed memory recall test (P > 0.05). Conclusion:, In conclusion, early recovery time was shorter in male patients compared to female patients in both the desflurane and sevoflurane groups. Additionally, in the desflurane groups it was shorter in the sevoflurane groups for both genders. [source]

Relationship between segment structures and elastic properties of segmented poly(urethane-urea) elastic fibers

POLYMER ENGINEERING & SCIENCE, Issue 11 2003
Nori Yoshihara
Studies on segmented poly(urethane-urea) (SPUU) elastic fibers having various segment structures were done in terms of elastic recovery and stress-strain relationship (S-S). Three kinds of segment structures were used: 1) the same composition having different sequences of segment units, 2) the same length of soft segments having different molecular weights of polyol, and 3) different segment structures having almost the same stress at 350% elongation. The SPUU elastic fibers having higher sequence numbers of both soft and hard segment units, that is, greater block structures, show better elastic recovery properties, especially delayed elastic recovery. The SPUU elastic fibers showing better elastic recovery take an optimum value for the number-average molecular weight (Mn) of soft segments jointed with urethane bonds. Here the optimum Mn depends on the molecular weight of polytetramethyleneglycol (PTMG) as a starting material. The hysteresis loss in S-S for the pre-elongation decreases with an increase of Mn of PTMG. The SPUU elastic fibers having greater block structures show lower stress with lower 2C1 and 2C1 + 2C2 of Mooney-Rivilin plot constants for elastic fibers having the same composition. This indicates a lower density of crosslinks for finite deformation. An increase of the urea bonds or the molar ratio of urea bond to urethane bond raises the stress. It is found that the polymerization process, as well as composition, is important for design structures of SPUU elastic fibers. [source]

A Rapidly Responding Sensor for Methanol Based on Electrospun In2O3,SnO2 Nanofibers

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2010
Wei Zheng
In this paper, we presented a simple and effective electrospinning technique for the preparation of In2O3,SnO2 composite nanofibers. The morphology and chemical structure of the as-prepared samples were analyzed by scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The results showed that large quantities of In2O3,SnO2 composite nanofibers with diameters from 60 to 100 nm were obtained. The In2O3,SnO2 composite nanofibers exhibited excellent gas sensing properties to methanol, such as fast response/recovery properties, high sensitivity, and good selectivity. [source]