Spinning Beta Silks Requires Both pH Activation and Extensional Stress

Synthetic silk production has undergone significant technological and commercial advances over the past 5 years, with fibers from most labs and companies now regularly matching the properties of natural silk by one metric or another. Yet the fundamental links between silk protein processing and performance remain largely unresolved and fiber optimization is commonly achieved through non-natural methods. In an effort to address this challenge, data that closes this loop of processing and performance is presented by spinning a native silk feedstock ex vivo into a near-native fiber using just two naturally occurring parameters; pH activation and extensional flow (i.e., spinning rate). This allows us to link previous experimental and modelling hypothesis surrounding silk's pH responsiveness directly to multiscale hierarchical structure development during spinning. Finally, fibers that match, and then exceed, natural silk's mechanical properties are spun and understood by rate of work input. This approach not only provides energetic insights into natural silk spinning and controlled protein denaturation, but is believed will help interpret and improve synthetic silk processing. Ultimately, it is hoped that these results will contribute towards novel bioinspired energy-efficient processing strategies that are driven by work input optimization and where excellent mechanical properties are self-emergent.     

Universal access: user needs for immersive captioning

Universal Access in the Information Society - This article focuses on building a prototyping for immersive captioning following a user-centric approach. This methodology is characterised by...     

Managing cognitive biases during disaster response: the development of an aide memoire

Disasters are highly complex with often extreme consequences and are often exacerbated by decision errors. Human behaviour in this domain offers a fertile     

Effects of substrate composition and roughness on mechanical properties and conformality of parylene C coatings

Nanoindentation was used to determine reduced elastic modulus E_r and hardness H of 16 μm thick Parylene C coatings vapor‐deposited on mill‐finished samples of aluminum, copper, nickel steel, and stainless steel. Profilometry was used to compare average surface roughnesses of the polymeric coatings to the roughnesses of the underlying metals, thereby providing a quantitative index for determining conformality. Roughness, elasticity, and hardness of coatings were found to be affected by both chemical composition and surface roughness of four different metallic substrates. Standard nanoindentation evaluations of E_r and H distributions for the various metals were found to be positively skewed, which precluded use of simple averages for purposes of comparison. However, analysis of the nanoindentation and profilometry data by use of alternative techniques indicated that coatings were consistently smoother and flatter than their underlying substrates, i.e., they were not truly conformal, and nanomechanical properties of Parylene C were affected by the chemical composition of the substrates independently of the effects of substrate roughness. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Ferrocene-Decorated Hyperbranched Poly(aroxycarbonylphenylene)s: Synthesis, Light Refraction, Photopatterning and Precursor to Magnetic Ceramics

Ferrocene-decorated hyperbranched poly[1,3,5-tri(aroycarbonyl)phenylene]s (hb-PTACPs) are prepared in moderate yields with high molecular weights by one-pot polycyclotrimerization of 4,4′-isopropylidenediphenyl bipropiolate with 4-(ferrocenylmethyl)phenyl propiolate in reflux dimethylformamide. All the polymers are soluble and film-forming. They enjoy high thermal stability and lost little of their weight when heated to 300 °C under nitrogen. Thin solid films of the organometallic polymers shows high refractive indices (RI = 1.7038–1.6295) in the wavelength region of 400–1,700 nm. Ceramization of the organometallic hb-PTACPs at high temperature under inert atmosphere gives iron nanoparticles with high magnetizabilities. The organometallic polymers are readily crosslinked under UV irradiation and pyrolysis of the patterned polymer films produces magnetic ceramic patterns with good shape retention.     

Don’t lock me in: Public opinion on the prospective use of waste process heat for district heating

While the available resource in terms of waste process heat in the UK is substantial, there are a wide variety of issues to consider and barriers to overcome in order to realise its potential. This paper discusses one particular factor, namely public opinion. We describe the results of two focus groups with a potential domestic client group, namely elderly people, and the postal questionnaire responses of 323 individuals living in the proximity of a large potential heat source, namely the Corus steel-works in Port Talbot, Wales. While those questioned were broadly supportive of the idea of district heating, particularly if this would involve reductions in domestic heating costs, both the qualitative and quantitative work revealed significant concern about contractual lock-in. In contrast, the stability of long-term demand is highly valued by those responsible for the supply-side. We also observe some gender differences in first reactions to district heating and the role of environmental commitment. We conclude that while the results imply that an appeal to the environmental performance of district heating with waste heat may facilitate acceptance, trust-building and price inducements will also be required to overcome end-user concerns.     

Effect of film thickness, type of buffer layer, and substrate temperature on the morphology of dicyanovinyl-substituted sexithiophene films

The influence of film thickness, type of buffer underlayer, and deposition substrate temperature on the crystal structure, microstructure, and morphology of the films of dicyanovinyl-substituted sexithiophene with four butyl-chains (DCV6T-Bu₄) is investigated by means of X-ray diffraction (XRD) and X-ray reflectivity methods. A neat Si wafer or a Si wafer covered by a 15 nm buffer underlayer of fullerene C₆₀ or 9,9-Bis[4-(N,N-bis-biphenyl-4-yl-amino)phenyl]-9H-fluorene (BPAPF) is used as a substrate. The crystalline nature and ordered molecular arrangement of the films are recorded down to 6 nm film thickness. By using substrates heated up to 90 °C during the film deposition, the size of the DCV6T-Bu₄ crystallites in direction perpendicular to the film surface increases up to value of the film thickness. With increasing deposition substrate temperature or film thickness, the DCV6T-Bu₄ film relaxes, resulting in reducing the interplane distances closer to the bulk values. For the films of the same thickness deposited at the same substrate temperature, the DCV6T-Bu₄ film relaxes for growth on Si to BPAPF to C₆₀. Thicker films grown at heated substrates are characterized by smaller density, higher roughness and crystallinity and better molecular ordering. A thin (up to about 6 nm-thick) intermediate layer with linear density-gradient is formed at the C₆₀/DCV6T-Bu₄ interface for the films with buffer C₆₀ layer. The XRD pattern of the DCV6T-Bu₄ powder is indexed using triclinic unit cell parameters.