Vacuum infusion of natural fibre composites for structural applications

Numerous methods of manufacturing natural fibre composites have been reported in the literature, including compression moudling, often in conjunction with a hot press. Other forms of composite manufacture include 'Vacuum Assisted Resin Transfer Moulding' (VATRM) and the 'Seemann Composite Resin Infusion Moulding Process' (SCRIMP). These methods have been reported to produce natural fibre composies with reasonable mechanical properties [1-2]. In this paper, a vacuum infusion rig is described that has been developed to produce consistent quality composite plates for studies into optimising natural fibre composites. The process aims to harness the benefits of vacuum infusion and compression moulding, where vacuum infusion encourages the removal of trapped air in the system and hence avoid reduction, and additional compression moulding can help to achieve high volume fractions that are otherwise difficult in other processes

Mechanical testing of natural fibre reinforced polyester resin composites and Mode 1 fracture toughness testing of resin blocks

Recent European Parliament directive requires companies to achieve materials recycling greater than 80% in particular in the automotive sector [1]. The research on natural fibre based composite materials fits well into this ecological image. The advantages of natural fibres over synthetic materials include, low density, relative cheapness, availability and biodegradability. In this paper we explore the fabrication and mechanical testing of natural fibre composites and this is part of an on going study at Strathclyde University and describes the fabrication of composites using natural fibre and styrene polyester resin. The properties of the synthetic resin can be varied by changing the catalysts concentration and flexural (three point bending) and single-edged notched bending (SENB) properties are reported at different concentrations of the catalyst

The effect of alkalisation on the mechanical properties of natural fibres

A study on the effect of alkalisaton using 3% NaOH solution was carried out on Flax, Kenaf, Abaca and Sisal to observe the impact that the common pre-treatment process has on fibre mechanical properties. The result of the investigation indicated that over-treatment of natural fibres using NaOH could have a negative effect on the base fibre properties. It is concluded that a treatment time of less than 10 minutes is sufficient to remove hemicelluloses and to give the optimum effect

Discovery of a filamentary synchrotron structure connected to the coherent magnetic field in the outer galaxy

Using data from the Galactic Arecibo L-band Feed Array Continuum Transit Survey, we report the discovery of two previously unidentified, very compressed, thin, and straight polarized filaments approximately centered at Galactic coordinates, (l, b) = (182°. 5, − 4°. 0), which we call G182.5–4.0. Using data from the Isaac Newton Telescope Galactic Plane Survey, we also find straight, long, and extremely thin Hα filaments coincident with the radio emission. These filaments are positioned in projection at the edge of the Orion-Eridanus superbubble and we find evidence indicating that the filaments align with the coherent magnetic field of the outer Galaxy. We find a lower limit on the total radio flux at 1.4 GHz to be 0.7 ± 0.3 Jy with an average linearly polarized fraction of 40 %20 30 - +. We consider various scenarios that could explain the origin of these filaments, including a shell type supernova remnant (SNR), a bow shock nebula associated with a pulsar, or relic fragments from one or more supernova explosions in the adjacent superbubble, with a hybrid scenario being most likely

Co-expression of C9orf72 related dipeptide-repeats over 1000 repeat units reveals age- and combination-specific phenotypic profiles in Drosophila

A large intronic hexanucleotide repeat expansion (GGGGCC) within the C9orf72 (C9orf72-SMCR8 Complex Subunit) locus is the most prevalent genetic cause of both Frontotemporal Dementia (FTD) and Motor Neuron Disease (MND). In patients this expansion is typically hundreds to thousands of repeat units in length. Repeat associated non-AUG translation of the expansion leads to the formation of toxic, pathological Dipeptide-Repeat Proteins (DPRs). To date there remains a lack of in vivo models expressing C9orf72 related DPRs with a repeat length of more than a few hundred repeats. As such our understanding of how physiologically relevant repeat length DPRs efect the nervous system in an ageing in vivo system remains limited. In this study we generated Drosophila models expressing DPRs over 1000 repeat units in length, a known pathological length in humans. Using these models, we demonstrate each DPR exhibits a unique, age-dependent, phenotypic and pathological profle. Furthermore, we show co-expression of specifc DPR combinations leads to distinct, age-dependent, phenotypes not observed through expression of single DPRs. We propose these models represent a unique, in vivo, tool for dissecting the molecular mechanisms implicated in disease pathology, opening up new avenues in the study of both MND and FTD

An evaluation of the stimulants and impediments to innovation within PFI/PPP projects

This paper identifies the theoretical stimulants and impediments associated with the implementation of PFI/PPP (Private Finance Initiative/Public Private Partnership) projects. A current defect of this procurement approach is the unintentional constraint upon the innovations incorporated into the development of PFI projects. A critical evaluation of the published literature has been utilized to synthesize a theoretical model. The paper proposes a theoretical model for the identification of potential innovation stimulants and impediments within this type of procurement. This theoretical model is then utilised to evaluate four previously completed PFI projects. These project case-studies have been examined in detail. The evaluation demonstrates how ineffective current procedures are. The application of this model before project letting could eliminate unintentional constraints and stimulate improved innovation within the process. The implementation of the model could improve the successful delivery of innovation within the entire PFI/PPP procurement process

Magnetic phase separation in ordered alloys

We present a lattice model to study the equilibrium phase diagram of ordered alloys with one magnetic component that exhibits a low temperature phase separation between paramagnetic and ferromagnetic phases. The model is constructed from the experimental facts observed in Cu$_{3-x}$AlMn$_{x}$ and it includes coupling between configurational and magnetic degrees of freedom which are appropriated for reproducing the low temperature miscibility gap. The essential ingredient for the occurrence of such a coexistence region is the development of ferromagnetic order induced by the long-range atomic order of the magnetic component. A comparative study of both mean-field and Monte Carlo solutions is presented. Moreover, the model may enable the study of the structure of the ferromagnetic domains embedded in the non-magnetic matrix. This is relevant in relation to phenomena such as magnetoresistance and paramagnetism.Comment: 12 pages, 11 figures, accepted in Phys. Rev.

Detecting metal-rich intermediate-age globular clusters in NGC4570 using K-band photometry

“The original publication is available at www.springerlink.com”. Copyright Springer. DOI: 10.1007/s10509-009-0093-8Globular cluster systems (GCSs) of most early-type galaxies feature two peaks in their optical colour distributions. Blue-peak globular clusters (GCs) are believed to be old and metal-poor, whereas the ages, metallicities, and the origin of the red-peak GCs are still being debated. We obtained deep K-band photometry and combined it with Hubble Space Telescope observations in g and z to yield a full spectral energy distribution from the optical to the near-infrared. This now allows us to break the age–metallicity degeneracy. We used our evolutionary synthesis models galev for star clusters to compute a large grid of models with different metallicities and a wide range of ages. Comparing these models to our observations revealed a large population of intermediate-age (1–3 Gyr) and metal-rich (≈solar-metallicity) GCs, that will give us further insights into the formation history of this galaxy.Peer reviewe

Gerbes, M5-Brane Anomalies and E_8 Gauge Theory

Abelian gerbes and twisted bundles describe the topology of the NS-NS 3-form gauge field strength H. We review how they have been usefully applied to study and resolve global anomalies in open string theory. Abelian 2-gerbes and twisted nonabelian gerbes describe the topology of the 4-form field strength G of M-theory. We show that twisted nonabelian gerbes are relevant in the study and resolution of global anomalies of multiple coinciding M5-branes. Global anomalies for one M5-brane have been studied by Witten and by Diaconescu, Freed and Moore. The structure and the differential geometry of twisted nonabelian gerbes (i.e. modules for 2-gerbes) is defined and studied. The nonabelian 2-form gauge potential living on multiple coinciding M5-branes arises as curving (curvature) of twisted nonabelian gerbes. The nonabelian group is in general $\tilde\Omega E_8$, the central extension of the E_8 loop group. The twist is in general necessary to cancel global anomalies due to the nontriviality of the 11-dimensional 4-form G field strength and due to the possible torsion present in the cycles the M5-branes wrap. Our description of M5-branes global anomalies leads to the D4-branes one upon compactification of M-theory to Type IIA theory.Comment: 19 page