147 research outputs found

    Generic flowsheet model for early inventory estimates of industrial microbial processes. II. Downstream processing

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    AbstractTo ensure optimal process flowsheet selection it is valuable to conduct environmental and economic comparisons at an early stage of technology selection and process design. However, the data that is needed to perform these studies are not available at this stage of process development. This is also true for bioprocess systems. To overcome the lack of data, the CeBER (Centre for Bioprocess Engineering Research, University of Cape Town) Bioprocess Modeller was developed to provide material and energy values for industrial microbial processes.This paper presents the downstream processing portion of this flowsheet. The model allows for solid–liquid separation, cell disruption, concentration and formulation units as required. The model allows section of appropriate downstream processing units include, amongst others, centrifugation, filtration, precipitation and freeze-drying. At each downstream processing stage, non-reacting and reacting chemicals can be added. The model provides both a material inventory as well as the calculation of the energy input required and waste heat generated.Additionally, the model includes a database of values (including constants, operating conditions and others), drawn from various industrial norms and academic sources. Should specific information not be known, the model selects the most appropriate values based on other decisions made through the model

    The use of honey in healing a recalcitrant wound following surgical treatment of hidradenitis suppurativa

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    Ancient civilizations used honey to heal wounds. Despite the rediscovery of honey by modern physicians1 its use in conventional medicine, unlike in complementary medicine, remains limited. Much anecdotal evidence, some clinical observations, some animal models and some randomised controlled trials support the efficacy of honey in managing wounds2,3 , but few detailed descriptions of the use of honey in healing difficult surgical wounds have previously been published

    QCD Corrections to QED Vacuum Polarization

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    We compute QCD corrections to QED calculations for vacuum polarization in background magnetic fields. Formally, the diagram for virtual eeˉe\bar{e} loops is identical to the one for virtual qqˉq\bar{q} loops. However due to confinement, or to the growth of αs\alpha_s as p2p^2 decreases, a direct calculation of the diagram is not allowed. At large p2p^2 we consider the virtual qqˉq\bar{q} diagram, in the intermediate region we discuss the role of the contribution of quark condensates \left and at the low-energy limit we consider the π0\pi^0, as well as charged pion π+π\pi^+\pi^- loops. Although these effects seem to be out of the measurement accuracy of photon-photon laboratory experiments they may be relevant for γ\gamma-ray burst propagation. In particular, for emissions from the center of the galaxy (8.5 kpc), we show that the mixing between the neutral pseudo-scalar pion π0\pi_0 and photons renders a deviation from the power-law spectrum in the TeVTeV range. As for scalar quark condensates \left and virtual qqˉq\bar{q} loops are relevant only for very high radiation density 300MeV/fm3\sim 300 MeV/fm^3 and very strong magnetic fields of order 1014T\sim 10^{14} T.Comment: 15 pages, 4 figures; Final versio

    Quality of mother-child interaction, differences in sexual attitudes, and inter-generational disagreement on sexuality.

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    The current paper examines the frequency of inter-generational disagreement reported by mothers and adolescents as a function of the quality of their interaction, and the match between their sexual attitudes. We expected that the quality of family interaction would act as a "family asset" that would enable members of families to manage and control the tensions caused by differences in (sexual) attitudes. Data on 319 British adolescent-mother pairs were analysed using structural equation modelling, revealing good support for these expectations: differences in sexual attitudes were more strongly linked to inter-family disagreement in low quality of mother-child interaction families than in high quality of motherchild interaction families. Implications of the study are discussed. © 1997 OPA (Overseas Publishers Association)

    Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

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    The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

    Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

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    A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

    Narrowband Searches for Continuous and Long-duration Transient Gravitational Waves from Known Pulsars in the LIGO-Virgo Third Observing Run

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    Isolated neutron stars that are asymmetric with respect to their spin axis are possible sources of detectable continuous gravitational waves. This paper presents a fully coherent search for such signals from eighteen pulsars in data from LIGO and Virgo's third observing run (O3). For known pulsars, efficient and sensitive matched-filter searches can be carried out if one assumes the gravitational radiation is phase-locked to the electromagnetic emission. In the search presented here, we relax this assumption and allow both the frequency and the time derivative of the frequency of the gravitational waves to vary in a small range around those inferred from electromagnetic observations. We find no evidence for continuous gravitational waves, and set upper limits on the strain amplitude for each target. These limits are more constraining for seven of the targets than the spin-down limit defined by ascribing all rotational energy loss to gravitational radiation. In an additional search, we look in O3 data for long-duration (hours-months) transient gravitational waves in the aftermath of pulsar glitches for six targets with a total of nine glitches. We report two marginal outliers from this search, but find no clear evidence for such emission either. The resulting duration-dependent strain upper limits do not surpass indirect energy constraints for any of these targets. © 2022. The Author(s). Published by the American Astronomical Society

    Response to ConvaTec critique

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