Hydropyrolysis: implications for radiocarbon pre-treatment and characterization of Black Carbon

Charcoal is the result of natural and anthropogenic burning events, when biomass is exposed to elevated temperatures under conditions of restricted oxygen. This process produces a range of materials, collectively known as pyrogenic carbon, the most inert fraction of which is known as Black Carbon (BC). BC degrades extremely slowly, and is resistant to diagenetic alteration involving the addition of exogenous carbon making it a useful target substance for radiocarbon dating particularly of more ancient samples, where contamination issues are critical. We present results of tests using a new method for the quantification and isolation of BC, known as hydropyrolysis (hypy). Results show controlled reductive removal of non-BC organic components in charcoal samples, including lignocellulosic and humic material. The process is reproducible and rapid, making hypy a promising new approach not only for isolation of purified BC for 14C measurement but also in quantification of different labile and resistant sample C fractions

Sports Mega-Events, Soft Power and Soft Disempowerment: international supporters’ perspectives on Qatar’s acquisition of the 2022 FIFA World Cup finals

Through conducting document analysis, field work, and semi-structured interviews at five major tournaments in Asia, North America, Europe and South America, the paper examines the perspectives of international football supporters on the Fédération Internationale de Football Association’s (FIFA) decision to award the 2022 World Cup finals to the State of Qatar. The paper is separated into five sections. First we ground Qatar’s sporting strategy within the concept of ‘soft power’, as well as pinpoint the negative consequences that have manifest since the state’s acquisition of the 2022 finals. Second, we disclose and defend our chosen data collection strategy. Third, we uncover and discuss our results with reference to three key themes: the state’s suitability as a football destination; the dubious awarding of the 2022 World Cup; and, Qatar’s cultural backdrop and domestic policies. Fourth, we align our findings to Qatar’s foreign policy intentions and ‘soft disempowerment’ consequences, locating in the process the opportunities and challenges that accompany the state’s hosting of the 2022 finals. We conclude by reflecting upon the contribution we have made here, as well as acknowledging the importance of Qatar for current and future sports mega-event research

Experimental characterisation of textile compaction response: A benchmark exercise

This paper reports the results of an international benchmark exercise on the measurement of fibre bed compaction behaviour. The aim was to identify aspects of the test method critical to obtain reliable results and to arrive at a recommended test procedure for fibre bed compaction measurements. A glass fibre 2/2 twill weave and a biaxial (±45°) glass fibre non-crimp fabric (NCF) were tested in dry and wet conditions. All participants used the same testing procedure but were allowed to use the testing frame, the fixture and sample geometry of their choice. The results showed a large scatter in the maximum compaction stress between participants at the given target thickness, with coefficients of variation ranging from 38% to 58%. Statistical analysis of data indicated that wetting of the specimen significantly affected the scatter in results for the woven fabric, but not for the NCF. This is related to the fibre mobility in the architectures in both fabrics. As isolating the effect of other test parameters on the results was not possible, no statistically significant effect of other test parameters could be proven. The high sensitivity of the recorded compaction pressure near the minimum specimen thickness to changes in specimen thickness suggests that small uncertainties in thickness can result in large variations in the maximum value of the compaction stress. Hence, it is suspected that the thickness measurement technique used may have an effect on the scatter

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

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

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

Diode-pumped ion-implanted crystal waveguide laser

We have recently reported the use of ion-implantation to form planar waveguide lasers in Nd:YAG crystals. Here, for the first time, we report diode pumped operation using a 500 mW diode array. We also describe the use of ion implantation to form planar waveguide lasers in Nd:YAP and Nd:MgO:LiNbO3

A low threshold quasi-three-level 946nm Nd:YAG epitaxial waveguide laser

We report the 946nm laser operation of an epitaxially grown Nd:YAG planar waveguide. The incident and absorbed power thresholds of 4mW and 1.2mW respectively are lower than those reported for bulk lasers when using a similar experimental set up. We also report the use of Ga doping of the active layer to increase the refractive index difference to allow the production of very small guiding layers

A low threshold epitaxially grown Nd:YAG waveguide laser operating at 946nm

The 946-mn transition of Nd:YAG has attracted interest asa possible source of diode- pumped blue light (after frequency doubling). A problem with this transition, however, is its three-level nature, with 0.7% of the total Nd population residing in the lower laser level at room temperature. Moving to a waveguide geometry gives the advantage of better light confinement, which should lead to significantly lower thresholds even despite some added propagation loss introduced by the guide

A side-pumped Nd:YAG epitaxial waveguide laser

We report the first operation of a side-pumped crystal waveguide laser. Both diode array and dye laser side-pumping of an epitaxially grown Nd:YAG planar waveguide laser have been demonstrated, with thresholds as low as 8 mW observed for a simple plane mirror cavity. Output slope efficiencies of 19% have also been demonstrated. The threshold and slope efficiency of this system is found to be in good agreement with a simple analytical model