A Comparative Study Between Weighing and Image Analysis Techniques for Predicting the Amount of Deposited Electrospun Nanofibres

Weighing and direct measurement are currently the two most common techniques used for estimating the amount of deposited nanofibres in electrospinning process. Nevertheless, due to its extremely small fibre size and mass, the task of measuring the weight or thickness of an electrospun nanofibres membrane is difficult and the results are arguable. This study evaluates the effectiveness of using greyscale image analysis for predicting the amount of deposited nanofibres compared to weighing technique. Polyvinyl alcohol electrospun nanofibres were collected at different deposition times on A4 black paper substrates. The substrates were weighed before and after deposition process and then scanned into 8 bit greyscale images. Analyses were carried out using ImageJ software, statistical analysis, high speed camera and scanning electron microscopy. At long deposition times, both techniques showed significant correlations between the measured values and deposition times. However, at short deposition times the weighing technique was found unreliable (p>0.05) compared to image analysis technique due to insignificant fibre masses compared to the weight variation of the substrates. Results suggest that image analysis technique was a better option to be used compared to weighing technique. This technique has the potential to be used as an automated online quality control in electrospun nanofibres manufacture

An investigation of using grey scale image analysis for predicting the amount of deposited electrospun nanofibres

When electrospinning, the amount of electrospun fibres deposited is difficult to determine due to the extremely small size and light weight of the fibres. Several methods have been used to predict the amount of deposited fibres including weighing, imaging and direct measurement. Although these methods work to a certain extent, they all have drawbacks that make them unsuitable for commercial scale process control. The methods are generally time consuming, destructive and only examine a small area of web. In this study, an image analysis method is used to predict the amount of electrospun fibres deposited over a significant area. When images of electrospun fibres are converted into grey scale images, it is suggested that the amount of fibres deposited can be predicted by measuring the grey scale intensity. A conventional weighing method was used to validate the image analysis results. The weighing method was found wanting when the deposition time was short (p>0.05). This was because the measured fibre masses were insignificant compared to the weight variation of the collector substrates. Statistical analyses showed that there were a strong correlation between grey scale intensity and deposition time especially at short deposition times. The results suggest that image analysis method could be used to predict the amount of deposited electrospun nanofibres. Further test on different polymers and different coloured substrates showed that the method was still capable to distinguish the samples. The developed method has the potential to be applied as an in-line non-destructive quality control method for electrospun fibre manufacture

Exact soliton solution and inelastic two-soliton collision in spin chain driven by a time-dependent magnetic field

We investigate dynamics of exact N-soliton trains in spin chain driven by a time-dependent magnetic field by means of an inverse scattering transformation. The one-soliton solution indicates obviously the spin precession around the magnetic field and periodic shape-variation induced by the time varying field as well. In terms of the general soliton solutions N-soliton interaction and particularly various two-soliton collisions are analyzed. The inelastic collision by which we mean the soliton shape change before and after collision appears generally due to the time varying field. We, moreover, show that complete inelastic collisions can be achieved by adjusting spectrum and field parameters. This may lead a potential technique of shape control of soliton.Comment: 5 pages, 5 figure

New evidence for strong nonthermal effects in Tycho's supernova remnant

For the case of Tycho's supernova remnant (SNR) we present the relation between the blast wave and contact discontinuity radii calculated within the nonlinear kinetic theory of cosmic ray (CR) acceleration in SNRs. It is demonstrated that these radii are confirmed by recently published Chandra measurements which show that the observed contact discontinuity radius is so close to the shock radius that it can only be explained by efficient CR acceleration which in turn makes the medium more compressible. Together with the recently determined new value $E_{sn}=1.2\times 10^{51}$ erg of the SN explosion energy this also confirms our previous conclusion that a TeV gamma-ray flux of $(2-5)\times 10^{-13}$ erg/(cm$^2$s) is to be expected from Tycho's SNR. Chandra measurements and the HEGRA upper limit of the TeV gamma-ray flux together limit the source distance $d$ to $3.3\leq d\leq 4$ kpc.Comment: 5 pages, 4 figures. Accepted for publication in Astrophysics and Space Science, Proc. of "The Multi-Messenger Approach to High-Energy Gamma-ray Sources (Third Workshop on the Nature of Unidentified High-Energy Sources)", Barcelona, July 4-7, 200

Palaeontology, the biogeohistory of Victoria

The broad-scale distribution of fossils within Victoria is controlled by general global patterns in the biological evolution of life on Earth, the local development and environmental evolution of habitats, and the occurrence of geological processes conducive to the preservation of fossil floras and faunas. Early Palaeozoic fossils are mostly marine in origin because of the predominance of marine sedimentary rocks in Victoria and because life on land was not significant during most of this time interval. Middle Palaeozoic sequences have both terrestrial and marine fossil records. Within Victoria, marine rocks are only very minor components of strata deposited during the late Palaeozoic, so that few marine fossils are known from this time period. A similar situation existed during most of the Mesozoic except towards the end of this era when marine conditions began to prevail in the Bass Strait region. During long intervals in the Cainozoic, large areas of Victoria were flooded by shallow-marine seas, particularly in the southern basins of Bass Strait, as well as in the northwest of the State (Murray Basin). Cainozoic sediments contain an extraordinary range of animal and plant fossils. During the Quaternary, the landscape of Victoria became, and continues to be, dominated by continental environments including, at times, extensive freshwater lake systems. Fossil floras and faunas from sediments deposited in these lake systems and from other continental sediments, as well as from Quaternary sediments deposited in marginal marine environments, collectively record a history of rapid fluctuations in climate and sea level.<br /

Is a randomised controlled trial of take home naloxone distributed in emergency settings likely to be feasible and acceptable? Findings from a UK qualitative study exploring perspectives of people who use opioids and emergency services staff

Objective Distribution of take-home naloxone (THN) by emergency services may increase access to THN and reduce deaths and morbidity from opioid overdose. As part of a feasibility study for a randomised controlled trial (RCT) of distribution of THN kits and education within ambulance services and Emergency Departments (EDs), we used qualitative methods to explore key stakeholders’ perceptions of feasibility and acceptability of delivering the trial. Methods We undertook semi-structured interviews and focus groups with 26 people who use opioids and with 20 paramedics and ED staff from two intervention sites between 2019 and 2021. Interviews and focus groups were recorded, transcribed verbatim and analysed using Framework Analysis. Results People using opioids reported high awareness of overdose management, including personal experience of THN use. Staff perceived emergency service provision of THN as a low-cost, low-risk intervention with potential to reduce mortality, morbidity and health service use. Staff understood the trial aims and considered it compatible with their work. All participants supported widening access to THN but reported limited trial recruitment opportunities partly due to difficulties in consenting patients during overdose. Procedural problems, restrictive recruitment protocols, limited staff buy-in and patients already owning THN limited trial recruitment. Determining trial effectiveness was challenging due to high levels of alternative community provision of THN. Conclusions Distribution of THN in emergency settings was considered feasible and acceptable for stakeholders but an RCT to establish the effectiveness of THN delivery is unlikely to generate further useful evidence due to difficulties in recruiting patients and assessing benefits

Electrostatic Potentials in Supernova Remnant Shocks

Recent advances in the understanding of the properties of supernova remnant shocks have been precipitated by the Chandra and XMM X-ray Observatories, and the HESS Atmospheric Cerenkov Telescope in the TeV band. A critical problem for this field is the understanding of the relative degree of dissipative heating/energization of electrons and ions in the shock layer. This impacts the interpretation of X-ray observations, and moreover influences the efficiency of injection into the acceleration process, which in turn feeds back into the thermal shock layer energetics and dynamics. This paper outlines the first stages of our exploration of the role of charge separation potentials in non-relativistic electron-ion shocks where the inertial gyro-scales are widely disparate, using results from a Monte Carlo simulation. Charge density spatial profiles were obtained in the linear regime, sampling the inertial scales for both ions and electrons, for different magnetic field obliquities. These were readily integrated to acquire electric field profiles in the absence of self-consistent, spatial readjustments between the electrons and the ions. It was found that while diffusion plays little role in modulating the linear field structure in highly oblique and perpendicular shocks, in quasi-parallel shocks, where charge separations induced by gyrations are small, and shock-layer electric fields are predominantly generated on diffusive scales.Comment: 7 pages, 2 embedded figures, Accepted for publication in Astrophysics and Space Science, as part of the HEDLA 2006 conference proceeding