A5069004782- Silk-based biomaterials and applications
- Liquid Crystal Research Advancements
- Silkworms and Sericulture Research
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Surfactants and Colloidal Systems
- Insect and Arachnid Ecology and Behavior
- Neurobiology and Insect Physiology Research
- Adhesion, Friction, and Surface Interactions
- Material Dynamics and Properties
- Advanced Materials and Mechanics
- Force Microscopy Techniques and Applications
- Polymer crystallization and properties
- Risk Management in Financial Firms
- Viral Infectious Diseases and Gene Expression in Insects
- Synthesis and Properties of Aromatic Compounds
- State Capitalism and Financial Governance
- Crystallography and molecular interactions
- Plant Reproductive Biology
- Mechanical Behavior of Composites
- Global Financial Crisis and Policies
- Surface Modification and Superhydrophobicity
- Insurance and Financial Risk Management
- Phytochemical compounds biological activities
- Theoretical and Computational Physics
University of California, Merced
2005-2023
Heriot-Watt University
1999-2016
Deakin University
2001-2011
University of Oxford
1996-2006
University College London
2004
Office of Public Affairs
2004
Heriot-Watt University Malaysia
2004
MicroVision (United States)
2004
University of Washington
1988-1997
Washington Center
1997
While silk exhibits high values of tensile strength and stiffness, these properties are compromised by their poor reproducibility. We present the results experiments aimed at characterizing variability exhibited cocoon from Bombyx mori silkworms. Scanning electron microscopy is used to measure an average diameter for individual test specimens; interspecimen quantified found be inadequately represented standard deviation. When load-extension data converted into stress-strain curves, a marked...
Mechanical tests were performed on single brins of Bombyx mori silkworm silk, to obtain values elastic modulus (E), yield strength, tensile breaking and shear (G). Specimen cross-sectional areas, needed convert loads into stresses, derived from diameter measurements by scanning electron microscopy. Results are compared with existing literature for partially degummed baves. The (16 ± 1 GPa) strength (230 10 MPa) B. brin significantly higher than the reported bave. difference is attributed...
Uniaxially oriented samples of thermotropic random copolyesters hydroxybenzoic and hydroxynaphthoic acids, acid ethylene terephthalate, have been characterised in detail using wide-angle X-ray diffraction. The technique was used to measure the global chain orientation, case first polymer meridional scattering has analysed terms diffraction from an isolated straight chain. Optical microstructures were observed between crossed polars, with circularly polarized light plane-polarised no analyser...
In contrast to the solid-state structures of individual compounds, arene-perfluoroarene face-to-face stacking and C–H‥F–C in-plane interactions dominate structure 1∶1 co-crystals 1,4-bis(phenylethynyl)-tetrafluorobenzene 1b 1,4-bis(pentafluorophenylethynyl)- benzene 1c, with this supramolecular aggregation leading stabilisation a nematic liquid crystalline phase.
A commonly adopted model for the microstructure of Nephila clavipes major ampullate silk (MAS) is similar to that used Bombyx mori (silkworm) silk: a simple composite wherein discrete, essentially perfect crystals are dispersed throughout an amorphous protein matrix. However, inconsistencies arise when researchers using complementary microstructural characterisation techniques attempt explain their results within framework. We present here findings our parallel studies in x-ray diffraction,...
The πs have it: An unusual 2:1 arene–perfluoroarene π complex is formed between 1,4-bis(phenylethynyl)benzene and its perfluorinated analogue, this the first example of a non-1:1 type. interstack geometry (see picture; red H, green F) also unusual, as mesomorphism system. Supporting information for article available on WWW under http://www.wiley-vch.de/contents/jc_2002/2004/z53828_s.pdf or from author. Please note: publisher not responsible content functionality any supporting supplied by...
Abstract Forcibly reeled silkworm ( Bombyx mori ) silk was used to study how exposure a degumming treatment (boiling in distilled water for 30 min) affects tensile properties. Because forcibly and naturally spun fibers exhibit comparable mechanical behavior, the results can be generalized material obtained conventionally from cocoons. The effects of include: decrease initial elastic modulus, stress at proportional limit (yield strength), change qualitative shape force‐displacement curves,...
The compounds 4-ROC6F4CCPh (4) where R = Me (a), Et (b), Prn (c), Pri (d), Bun (e), n-C5H11 (f), PhCH2 (g), PhCH2CH2 (h), 4-MeC6H4 (i), 4-EtC6H4 (j) and menthyl (k), have been prepared by reaction of C6F5CCPh (3) with ROH in the presence KOH, characterised NMR (1H, 13C, 19F) mass spectroscopy. single-crystal structures PhCCPh·C6F5CCC6F5 (1∶2), 3 4a,c,d,f,g,i determined X-ray diffraction at 120–160 K, that also calculated an ab initio pseudo-potential DFT method. tolan moiety is nearly planar...
Abstract Perfluorodecyl decane, F(CF2)10(CH2)10H, is shown to undergo a liquid crystal-liquid crystal transition above room temperature. The accompanying reversible structural reorganization observed by transmitted polarized light microscopy, small angle x-ray scattering and wide diffraction. Both crystalline phases have layered structure; within the layers molecules are interdigitated, tilted relative layer normal, packed in pseudo-hexagonal fashion. transformation between structures...
Abstract We report the first direct observations of physical and chemical microstructure spider dragline, revealed by analytical transmission electron microscopy. Individual crystallites were imaged within amorphous matrix. They are irregularly shaped, approximately 70–100 nm in diameter, uniformly distributed throughout Electron diffraction determined their space group to be P2 1 . The corresponding orthogonal cell has lattice parameters a = 13.31 Å (β‐sheet repeat), b 9.44 (interchain...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHigh-temperature structures of poly(p-hydroxybenzoic acid)Do Y. Yoon, Norberto Masciocchi, Laura E. Depero, Christopher Viney, and William ParrishCite this: Macromolecules 1990, 23, 6, 1793–1799Publication Date (Print):March 1, 1990Publication History Published online1 May 2002Published inissue 1 March 1990https://pubs.acs.org/doi/10.1021/ma00208a039https://doi.org/10.1021/ma00208a039research-articleACS PublicationsRequest reuse permissionsArticle...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe nature of the thermal transitions in poly(p-oxybenzoate)J. Economy, W. Volksen, C. Viney, R. Geiss, Siemens, and T. KarisCite this: Macromolecules 1988, 21, 9, 2777–2781Publication Date (Print):September 1, 1988Publication History Published online1 May 2002Published inissue 1 September 1988https://pubs.acs.org/doi/10.1021/ma00187a023https://doi.org/10.1021/ma00187a023research-articleACS PublicationsRequest reuse permissionsArticle...
Abstract The tensile properties of Argiope trifasciata (Argiopidae) drag line silk retrieved from mooring threads in the web were characterized. Scanning electron microscope images used to determine cross‐sectional area samples, allowing force‐displacement plots be rescaled as stress–strain curves and characterize fracture surfaces. Twenty‐eight samples tested obtain statistically significant values mechanical parameters (elastic modulus, stress strain at proportional limit, strength)....
Abstract Bave was acquired by the forced silking of three Bombyx mori silkworms, and its tensile properties were characterized. The material collected from any given silkworm yielded reproducible force‐displacement plots, which qualitatively similar to plots obtained silk other silkworms. This uniformity contrasts with highly variable exhibited had been reeled degummed cocoons. Scanning electron microscopy images used obtain information about sample cross‐sectional area, so that could be...
Abstract The semifluorinated alkanes F(CF2)10(CH2)9H and F(CF2)10(CH2)11H both undergo a reversible transition between tilted smectic phases above room temperature as demonstrated previously for F(CF2)10(CH2)10H. transformation on cooling is achieved in two stages: an increase molecular tilt relative to the layer normal, followed by change interdigitation within each layer. extent of complete sensitive time, due strains occasioned accompanying volume change, because second stage requires...