A. L. Woodhead, T. D. Sutherland, J. S. Church

Bombus terrestris, commonly known as the buff-tailed bumblebee, is native to Europe, parts of Africa and Asia. It is commercially bred for use as a pollinator of greenhouse crops. Larvae pupate within a silken cocoon that they construct from proteins produced in modified salivary glands. The amino acid composition and protein structure of hand drawn B. terrestris, silk fibres was investigated through the use of micro-Raman spectroscopy. Spectra were obtained from single fibres drawn from the larvae salivary gland at a rate of 0.14 cm/s. Raman spectroscopy enabled the identification of poly(alanine), poly(alanine-glycine), phenylalanine, tryptophan, and methionine, which is consistent with the results of amino acid analysis. The dominant protein conformation was found to be coiled coil (73%) while the β-sheet content of 10% is, as expected, lower than those reported for hornets and ants. Polarized Raman spectra revealed that the coiled coils were highly aligned along the fibre axis while the β-sheet and random coil components had their peptide carbonyl groups roughly perpendicular to the fibre axis. The protein orientation distribution is compared to those of other natural and recombinant silks. A structural model for the B. terrestris silk fibre is proposed based on these results.

P. Church, A. Goscinski

Through the use of cloud platforms, software packages have been centralised and made available as services. Utilising these software services require that data is retrieved from public and private data servers (called biological databases). These data servers are: difficult to discover, lack standardised access, and are time consuming to manage. In response, we propose a new approach in which data servers and files are abstracted in a similar manner to software services. This new approach uses meta-data to represent data servers and files as services. Data servers and files are discoverable and managed through a broker. Each data server service encapsulates the protocols required to access, and transfer data. When integrated into a cloud platform, this approach allows for users to take advantage of cloud, cluster, and biological database resources in a uniform manner, via web interfaces.

A. L. Woodhead, B. Cosgrove, J. S. Church

Prior to the 19th century the use of purple dyes for textile coloration was expensive and usually limited to royalty. The discovery of several synthetic purple dyes during the 19th century made the production of purple textiles more affordable and thus more readily available. The identification of the source of the purple coloration is of historical interest. Small yarn samples from four late 19th century silk dresses were analyzed using a ombination of thin layer chromatography and surface enhanced Raman spectroscopy, Fourier transform infrared spectroscopy and energy dispersive x-ray spectroscopy. This combination of techniques enabled the analysis of the complex extraction products. While three of the dresses were found to be dyed using methyl violet, the fourth dress was found to be constructed from a warp yarn dyed with methyl violet in the presence of a tannic acid mordant, and a weft yarn dyed with mauve and a tin mordant.

Q. Li, J. S. Church, M. Naebe, B. L. Fox

Carbon nanotube (CNT) deposition onto carbon fibre resulting in hybrid surface structures with various morphologies were successfully carried out using electrospray technique. In terms of tensile testing and Weibull analysis this process did not degrade fibre mechanical properties. When incorporated into composites, the interfacial shear strength (IFSS), as measured by single fibre fragmentation testing, increased by up to 124%. Experimental work was carried out to develop a deeper understanding of the interfacial reinforcing mechanism. Contact angle measurements demonstrated that the CNT deposition resulted in good wettability by the resin. Significant increases in roughness, friction and surface area were also found after CNT deposition, especially for the sample prepared using the parameter of 20 kV/10 cm at 100 °C. Surface energy analysis revealed that an increase in the dispersive surface energy due to the CNTs likely contributed to the improvement of interaction between fibre and matrix. Fractographic analysis revealed that the length of fibre pull-out and the size of cracks between the fibre and matrix were markedly decreased in the hybrid CNT surface structure, indicating that the stress transfer and interfacial shear strength have been improved. Finally, the potential for further improvement in interfacial composite properties by this approach was assessed.

Q. Li, J. S. Church, M. Naebe, B. L. Fox

By electrospraying solvent dispersed carbon nanotubes (CNTs) with a binder onto carbon fibre (CF), hybrid structures, with an end aim to improve interfacial bonding in composites, were formed. The electrospray parameters controlling the modification of the CNT morphologies were studied. High-speed camera observations found applied voltage was critical for determining spray mode development. Electric field simulations revealed a concentrated electric field region around each fibre. Both voltage and distance played an important role in determining the CNT morphology by mediating anchoring strength and electric field force. The forming mechanism investigation of different surface morphologies suggested that binder with appropriate wetness gives freedom to the CNTs, allowing them to orientate radially from the CF surface. Linear density (LD) measurements and thermogravimetric analysis revealed that a 10 min coating increased the LD of a single CF filament by up to 31.7% while a 1 h treatment increased fibre bundle mass by 1%.

J. Y. Cai, J. McDonnell, C. Brackley, L. O'Brien, J. S. Church, K. Millington, S. Smith, N. Phair-Sorensen

This paper reports on a significant advancement in carbon fiber precursor research. We have successfully applied reversible addition-fragmentation chain transfer (RAFT) technology to polyacrylonitrile (PAN) based carbon fiber precursor synthesis, and developed new PAN precursor polymers with a high molecular weight (M_n > 300 K), while still maintaining a low polydispersity index (PDI) (< 1.2). This desirable molecular profile has not been attainable until now. The paper also reports on the very first comparative study carried out for assessing the properties and performance of such a high molecular weight, low PDI precursor and its resultant carbon fiber against the conventional controls. In this comparative study, a control precursor polymer with a closely matching molecular weight and comonomer content was prepared by conventional free radical polymerization. Both of the RAFT mediated PAN (RAFT PAN) and control PAN precursor polymers were processed into precursor fibers and carbon fibers under identical conditions. The structures and properties of these fibers were characterized and evaluated. The results of this preliminary study have demonstrated a signifcant improvement in the rheological property of RAFT PAN polymer, and significant improvement in the mechanical properties of the precursor fiber and carbon fiber derived from the RAFT PAN precursor polymer.

K. Badii, J. S. Church, G. Golkarnarenji, M. Naebe, H. Khayyam

The production of carbon fiber, particularly the oxidation/stabilization step, is a complex process. In the present study, a non-linear mathematical model has been developed for the prediction of density of polyacrylonitrile (PAN) and oxidized PAN fiber (OPF), as a key physical property for various applications, such as energy and material optimization, modeling, and design of the stabilization process. The model is based on the available functional groups in PAN and OPF. Expected functional groups, including -C≡N,-C=N, -CH₂, -C=C, and -C=O, were identified and quantified through the full deconvolution analysis of Fourier transform infrared attenuated total reflectance (FT-IR ATR) spectra obtained from fibers. These functional groups form the basis of three stabilization rendering parameters, representing the cyclization, dehydrogenation and oxidation reactions that occur during PAN stabilization, and are used as the independent variables of the non-linear predictive model. The k-fold cross validation approach, with k = 10, has been employed to find the coefficients of the model. This model estimates the density of PAN and OPF independent of operational parameters and can be expanded to all operational parameters. Statistical analysis revealed good agreement between the governing model and experiments. The maximum relative error was less than 1% for the present model.

P. Church, A. Goscinski, C. Lefèvre

Cloud and service computing has started to change the way research in science, in particular biology and medicine, is being carried out. Researchers that have taken advantage of this technology (making use of public and private cloud compute resources) can process large amounts of data (big data) and speed up discovery. However, this requires researchers to acquire a solid knowledge and skills in the development of sequential and high performance computing (HPC), and cloud development and deployment background. In response a technology exposing HPC applications as services through the development and deployment of a SaaS cloud, and its proof of concept in the form of implementation of a cloud environment, Uncinus, has been developed and implemented to allow researchers easy access to cloud computing resources. The new technology offers and Uncinus supports the development of applications as services and the sharing of compute resources to speed up applications’ execution. Users access these cloud resources and services through web interfaces. Using the Uncinus platform, a bio-informatics workflow was executed on a private (HPC) cloud, server and public cloud (Amazon EC2) resources, performance results showing a 3 fold improvement compared to local resources’ performance. Biology and medicine specialists with no programming and application deployment on clouds background could run the case study applications with ease.