Assessing the size and uncertainty of remaining carbon budgets

The remaining carbon budget (RCB), the net amount of CO2 humans can still emit without exceeding a chosen global warming limit, is often used to evaluate political action against the goals of the Paris Agreement. RCB estimates for 1.5 °C are small, and minor changes in their calculation can therefore result in large relative adjustments. Here we evaluate recent RCB assessments by the IPCC and present more recent data, calculation refinements and robustness checks that increase confidence in them. We conclude that the RCB for a 50% chance of keeping warming to 1.5 °C is around 250 GtCO2 as of January 2023, equal to around six years of current CO2 emissions. For a 50% chance of 2 °C the RCB is around 1,200 GtCO2. Key uncertainties affecting RCB estimates are the contribution of non-CO2 emissions, which depends on socioeconomic projections as much as on geophysical uncertainty, and potential warming after net zero CO2

Assessing the size and uncertainty of remaining carbon budgets

The remaining carbon budget (RCB), the net amount of CO₂ humans can still emit without exceeding a chosen global warming limit, is often used to evaluate political action against the goals of the Paris Agreement. RCB estimates for 1.5 °C are small, and minor changes in their calculation can therefore result in large relative adjustments. Here we evaluate recent RCB assessments by the IPCC and present more recent data, calculation refinements and robustness checks that increase confidence in them. We conclude that the RCB for a 50% chance of keeping warming to 1.5 °C is around 250 GtCO₂ as of January 2023, equal to around six years of current CO₂ emissions. For a 50% chance of 2 °C the RCB is around 1,200 GtCO₂. Key uncertainties affecting RCB estimates are the contribution of non-CO₂ emissions, which depends on socioeconomic projections as much as on geophysical uncertainty, and potential warming after net zero CO₂

Multi-layered Ruthenium-modified Bond Coats for Thermal Barrier Coatings

Diffusional approaches for fabrication of multi-layered Ru-modified bond coats for thermal barrier coatings have been developed via low activity chemical vapor deposition and high activity pack aluminization. Both processes yield bond coats comprising two distinct B2 layers, based on NiAl and RuAl, however, the position of these layers relative to the bond coat surface is reversed when switching processes. The structural evolution of each coating at various stages of the fabrication process has been and subsequent cyclic oxidation is presented, and the relevant interdiffusion and phase equilibria issues in are discussed. Evaluation of the oxidation behavior of these Ru-modified bond coat structures reveals that each B2 interlayer arrangement leads to the formation of α-Al 2 O 3 TGO at 1100°C, but the durability of the TGO is somewhat different and in need of further improvement in both cases

Vasculogenic properties of adventitial Sca-1(+)CD45(+) progenitor cells in mice: a potential source of vasa vasorum in atherosclerosis

The cellular origins of vasa vasorum are ill-defined and may involve circulating or local progenitor cells. We previously discovered that murine aortic adventitia contains Sca-1⁺CD45⁺ progenitors that produce macrophages. Here we investigated whether they are also vasculogenic. In aortas of C57BL/6 mice, Sca-1⁺CD45⁺ cells were localised to adventitia and lacked surface expression of endothelial markers (<1% for CD31, CD144, TIE-2). In contrast, they did show expression of CD31, CD144, TIE-2 and VEGFR2 in atherosclerotic ApoE(-/-) aortas. Although Sca-1⁺CD45⁺ cells from C57BL/6 aorta did not express CD31, they formed CD31⁺ colonies in endothelial differentiation media and produced interconnecting vascular-like cords in Matrigel that contained both endothelial cells and a small population of macrophages, which were located at branch points. Transfer of aortic Sca-1⁺CD45⁺ cells generated endothelial cells and neovessels de novo in a hindlimb model of ischaemia and resulted in a 50% increase in perfusion compared to cell-free control. Similarly, their injection into the carotid adventitia of ApoE(-/-) mice produced donor-derived adventitial and peri-adventitial microvessels after atherogenic diet, suggestive of newly formed vasa vasorum. These findings show that beyond its content of macrophage progenitors, adventitial Sca-1⁺CD45⁺ cells are also vasculogenic and may be a source of vasa vasorum during atherogenesis.Deborah Toledo-Flores, Anna Williamson, Nisha Schwarz, Sanuja Fernando, Catherine Dimasi, Tyra A. Witt, Thao M. Nguyen, Amrutesh S . Puranik, Colin D. Chue, Sinny Delacroix, Daniel B. Spoon, Claudine S. Bonder, Christina A. Bursill, Belinda A. Di Bartolo, Stephen J. Nicholls, Robert D. Simari, Peter J. Psalti

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