Creation of an ultra scale-down bioreactor mimic for rapid development of lignocellulosic enzymatic hydrolysis processes

BACKGROUND Cellulosic bioethanol processes involve several steps, all of which require experimental optimisation. A significant aid to this research would be a validated ultra scale-down (USD) model that could be used to perform rapid, wide ranging screening and optimisation experiments using limited materials under process relevant conditions. RESULTS In this work, the use of 30 mL shaken conical tubes as a USD model for an enzymatic hydrolysis process is established. The approach is demonstrated for the hydrolysis of distillers' dried grains with solubles (DDGS). Results from the USD tubes closely mimic those obtained from 4 L stirred tanks, in terms of the rate, composition and concentrations of sugars released, representing an 80-fold scale reduction. The utility of the USD approach is illustrated by investigating factors that may be limiting hydrolysis yields at high solids loadings. Washing the residual solids periodically during hydrolysis allowed 100% of the available sugar to be hydrolysed using commercially available enzymes. CONCLUSION The results demonstrate that the USD system reported successfully mimics the performance of conventional stirred tanks under industrially relevant conditions. The utility of the system was confirmed through its use to investigate performance limitation using a commercially relevant feedstock

Emergence of noncollinear magnetic ordering in small magnetic clusters: Mnn_n and As@Mnn_n

Using first-principles density functional calculations, we have studied the magnetic ordering in pure Mn$_n$ ($n=2-$10, 13, 15, 19) and As@Mn$_n$ ($n=1-$10) clusters. Although, for both pure and doped manganese clusters, there exists many collinear and noncollinear isomers close in energy, the smaller clusters with $n\leqslant$5 have collinear magnetic ground state and the emergence of noncollinear ground states is seen for $n\geqslant$6 clusters. Due to strong $p-d$ hybridization in As@Mn$_n$ clusters, the binding energy is substantially enhanced and the magnetic moment is reduced compared to the corresponding pure Mn$_n$ clusters.Comment: 10 Pages and 5 Figure

Hayek and social justice: a critique

Hayek dismisses social justice on the grounds of its atavism, meaninglessness, unfeasibility and incompatibility with a liberal market society. Despite this, he concedes a role for the state in directly providing an economic minimum for those unable to provide one for themselves. This leaves his position in a profound self-contradiction. On the one hand social justice is dismissed as an unworkable, atavistic ‘mirage’ whilst on the other a minimum safety net is defended on grounds which contradict three of the four critiques. Given that in order to remain distinctively classical liberal Hayek must reject social justice, the fact that he did not argue against direct provision by the state of even minimal welfare shows that his contribution fails. His concession is all the more curious given that his epistemological liberalism provides the conceptual resources necessary for a positive response to the concerns that motivate social justice without invoking a direct role for the state

More open borders and deep structural transformation

Building upon recent work on epistemic varieties of liberalism, avant-garde political agency and the theory and practice of activism, I claim that a liberal defence of more open borders does not presuppose either indifference to the problem of the deep structural sources of poverty in poorer countries, or the absence of an account of those structures’ transformation. Rather, it is claimed that in addition to the remittance of money and other economic goods to alleviate the symptoms of poverty, more open borders facilitate the remittance of norms and values in terms of which individuals and activist communities in poorer countries may transform the deep structures and institutions that are poverty’s sources. This liberal account of more open borders and deep structural transformation also makes possible the non-coercive discharge of obligations of global justice on the part of wealthier states to the world’s poor, when poorer nations are either unable or unwilling to discharge them themselves

Macroscopic Quantum Tunneling of Ferromagnetic Domain Walls

Quantum tunneling of domain walls out of an impurity potential in a mesoscopic ferromagnetic sample is investigated. Using improved expressions for the domain wall mass and for the pinning potential, we find that the cross-over temperature between thermal activation and quantum tunneling is of a different functional form than found previously. In materials like Ni or YIG, the crossover temperatures are around 5 mK. We also find that the WKB exponent is typically two orders of magnitude larger than current estimates. The sources for these discrepancies are discussed, and precise estimates for the transition from three-dimensional to one-dimensional magnetic behavior of a wire are given. The cross-over temperatures from thermal to quantum transitions and tunneling rates are calculated for various materials and sample sizes.Comment: 10 pages, 2 postscript figures, REVTe

"I suddenly had a voice" : a qualitative study of patient experiences of violence and treatment in a Dangerous and Severe Personality Disorder (DSPD) unit.

Narratives give direction, purpose and meaning to people’s lives and are a key component in the development of personality. In forensic psychology, violent offending is most often presented as a set of enduring dispositional traits. It is argued, however, that an analysis of narratives may also offer useful insights into what sustains offending and what might lead to change. This review examines the literature on adult offender narratives and their function within correctional cultures and society. It suggests that practitioners may wish to consider incorporating features of what an offender is trying to achieve through their narratives into existing programmes of rehabilitation to ensure future gains are sustained. The implications of this are discussed. This study investigates the personal accounts of patients in a UK Dangerous and Severe Personality Disorder (DSPD) Unit who are engaging in treatment to help them manage their violent / offending behaviour. Ten participants were interviewed and their interviews were analysed using Interpretive Phenomenological Analysis (IPA). Four master themes surfaced: “A dog eat dog world” shows how violence became a legitimate response to early, abusive environments; “No-one really saw that side of me” explores how alterative ways of behaviour were deterred and difficult to relinquish; “Finding a voice” describes participants’ experiences of change and what they see as important components of it; and ‘Fears for the future’ considers the difficulties that still lie ahead. As the DSPD pilot ends, how these experiences might help augment existing clinical treatment programmes are discussed

On the circumstances of justice

An epistemic account of the circumstances of justice allows one to make three important claims about the Humean and Rawlsian ‘standard account’ of those circumstances. First, and contrary to Hume, the possibility and necessity of justice are rooted not in limited beneficence or confined generosity, but in the epistemic insight that the knowledge relevant to deciding what to do with the fruits of social cooperation is for a variety of reasons uncentralisable. Second, and regardless of whether Rawlsian ethical disagreement is more persuasive as a circumstance of justice than Humean confined generosity, it does not explain the possibility and necessity of justice, for the uncentralisability of social knowledge would be decisive even under conditions of unanimity. Finally, the epistemic account not only shows what the circumstances of justice are but, contra Cohen’s critique of the standard account, also provides at least some guidance as to what justice itself may be

More open borders for those left behind

Including the interests of those migrants leave behind in debates about migration and justice is a strategy which theorists who are sceptical of open borders have made use of, most notably in brain drain critiques of emigration. In rejecting this view, and in invoking an epistemic conception of liberalism, I claim that not only can the interests of those left behind be appealed to by defenders of more open borders. For at least two reasons such interests should be included. First, more open borders have a unique role to play in addressing the interests of those left behind via the transformative economic effects of remittances and the state signalling mechanism that migrant and remittance flows provide, both for wealthier states as they dispense foreign aid and for poorer states as they implement national development programmes. Second, more open borders are also compelling for those who are sceptical of immigration insofar as they help them identify the obligations of justice they may owe to the world’s poor and how these are best discharged; obligations whose fulfilment lessens the pressure to migrate from poorer to wealthier states over the long term

Nickel coatings by Inductively Coupled Impulse Sputtering (ICIS)

Inductively Coupled Impulse Sputtering (ICIS) removes the need for a magnetron, whilst delivering equal or higher ion-to-neutral ratios compared to other ionised PVD technologies such as High Power Impulse Magnetron Sputtering (HIPIMS). This is especially advantageous for the sputtering of magnetic materials, as these would shunt the magnetic field of the magnetron, thus reducing the efficiency of the sputtering and ionisation process. ICIS produces highly ionised metal-dominated plasma inside a high power pulsed RF-coil with a magnet free high voltage pulsed DC powered cathode. ICIS operation with magnetic target materials has not been attempted so far. The paper aims to clarify the effects of power and pressure on the chemistry of the deposition flux and is the first investigation of the microstructure of ICIS deposited coatings. Modelling based on the intensity of the optical emission spectra (OES) is conducted for the first time on the excited species of Ni and Ar in relation to the applied RF-power. Sputtered species show a linear intensity increase for increasing peak RF-power and constant process gas pressure. The influence of increasing process gas pressure on the ionisation was studied at a constant peak RF-power for pressures. For pressures below 8 Pa the intensity rises, but then remains constant for pressures up to 26 Pa. The microstructure of Ni coatings shows columnar dendritic or globular growth depending on the ionisation degree. In relation to the film thickness on the top of the substrate, the bottom coverage of unbiased vias with an aspect ratio of 4:1 was 15% and for lower aspect ratios of 1.5:1 was 47.5%. The current work has shown that the concept of combining a pulsed RF driven coil with a magnet-free pulsed DC powered cathode works well for the sputtering of magnetic material in a stable plasma

Magnetic Nanoparticles in the Interstellar Medium: Emission Spectrum and Polarization

The presence of ferromagnetic or ferrimagnetic nanoparticles in the interstellar medium would give rise to magnetic dipole radiation at microwave and submm frequencies. Such grains may account for the strong mm-wavelength emission observed from a number of low-metallicity galaxies, including the Small Magellanic Cloud. We show how to calculate the absorption and scattering cross sections for such grains, with particular attention to metallic Fe, magnetite Fe3O4, and maghemite gamma-Fe2O3, all potentially present in the interstellar medium. The rate of Davis-Greenstein alignment by magnetic dissipation is also estimated. We determine the temperature of free-flying magnetic grains heated by starlight and we calculate the polarization of the magnetic dipole emission from both free-fliers and inclusions. For inclusions, the magnetic dipole emission is expected to be polarized orthogonally relative to the normal electric dipole radiation. Finally, we present self-consistent dielectric functions for metallic Fe, magnetite Fe3O4, and maghemite gamma-Fe2O3, enabling calculation of absorption and scattering cross sections from microwave to X-ray wavelengths.Comment: submitted to Ap.J. Fig. 10 has been corrected. Minor changes to the discussion in section 10.2.