A jet grouting trial was undertaken within the Thames Tideway Tunnel shaft at Kirtling Street in Battersea, SW London, to assess the viability of the technique within the Lambeth Group and Thanet Formation sediments up to 60 m below ground level. There was no precedent industry experience of jet grouting in the UK at this depth and in these soil types. Four, separate, upper and lower grout columns were constructed respectively within upper and lower granular zones inside the shaft footprint, and then exhumed for inspection and measurement during ensuing excavation within the diaphragm wall lining. Target diameters for the upper columns were achieved within granular channel sand and Laminated Bed material, with minimal vertical deviation. These were not so successfully achieved, however, within stiff cohesive Laminated Bed and Lower Shelly Clay materials. Formation of the lower columns was severely restricted in dense gravel belonging to the ‘Pebble Bed’ and stiff gravelly clay, at the top of the Upnor Formation, but target diameters were being achieved in the lower portion of the formation, comprising Upnor sand. At their base, the column diameters were, again, restricted in the very dense sand at the top of the Thanet Formation.

A new class of solutions of the ultimate extinction probability for a neutron fission chain have been derived from Galton-Watson processes, which allows for a significant simplification in their derivation with respect to the conventional probability balance approach. These solutions are not based on the one-group diffusion hypothesis, depend only on the effective multiplication value and allow to take into consideration a large variety of discrete fission neutron distributions. They have been compared to other solutions, derived from probability balance equations, and they are qualitatively in good agreement. Additionally, the polynomial form of a model based on the geometric distribution presented here, has allowed for the calculation of the alive neutrons probability distribution that has been compared, for different generation numbers, with criticality benchmarks’ distributions estimated via a neutron Monte Carlo code. The comparisons have shown good agreement for generation numbers larger than 1.

A common practice in many transport models is to allocate all costs to the car driver meaning that car passengers are essentially free riders. This specification provides an easy way of integrating drivers and passengers and fits well with the general understanding that car drivers rarely trade passenger seats for money. However, in this paper, we question this premise and argue that cost sharing can, and most likely will, take place in a variety of forms different from simple out-off-pocket money exchange. We also stress that from a modelling perspective, this issue is far from irrelevant as it influences not only demand elasticities but also the modelling of car occupancy rates which is one of the key variables when considering congestion, climate impacts, and network utilisation. In the paper we discuss the mechanisms by which costs are shared, consider how this can be operationalised in transport models, and finally, consider the consequences of cost sharing from a transport policy perspective. Based on empirical evidence from Denmark, we find that for trip purposes with high occupancy rates, cost elasticities and occupancy rates tend to be biased if cost sharing is not properly accounted for.

Significant cost benefits through plant simplification can be achieved if a soluble boron-free lithiated primary water chemistry can be demonstrated to be viable for small modular reactor operation. However, the mechanisms of accelerated corrosion behavior of the zirconium alloy clad material under lithiated and boron-free autoclave conditions have yet to be fully identified. Advanced microstructural characterization of selected samples from the testing program, combined with atomistic simulation, have allowed for a significant development in the understanding of the mechanism of lithium-enhanced acceleration under boron-free conditions. Density functional theory has been used to identify the most stable accommodation mechanisms for lithium in tetragonal, monoclinic, and amorphous ZrO2 and its impact upon the defect population at an atomic scale. Atom probe tomography has confirmed that lithium predominantly segregates to oxide grain boundaries under elevated lithium conditions. The combination of modeling and advanced characterization has suggested that lithium-enhanced acceleration is linked to a local grain boundary effect caused by the segregation of lithium that increases the oxygen vacancy concentration within the usually protective barrier layer and leads to accelerated corrosion rates.

AbstractAfrica's population is expected to triple by 2050, owing to rapid urbanisation and overall demographic trends. The combined pressures of urbanisation and climate change impact the ecosystem and the services it provides. As a result, additional dangers such as increased flooding, and environmental disruption have risen. Therefore, devising adaptive solutions to mitigate flood risk impacts while also building community resilience is needed. Evidence suggests that Nature‐based Solutions (NbS) can potentially alleviate floods and mitigate climate change impacts while also delivering other societal benefits. Despite rising NbS popularity following its recognition in the last decade, studies on its recognition in Africa remain limited. For this reason, this paper reviewed NbS studies conducted in East Africa (EA) to evaluate opportunities and barriers surrounding NbS adoption in EA. Academic literature published from January 2012 to May 2022 was reviewed using a comprehensive search of the SCOPUS database. Results show 14 papers have been published during the period, with the majority being post‐2020. In addition, the majority of the articles focused on cities and peri‐urban settlements, while public awareness, clear guidelines on performance monitoring, stakeholder inclusion, and diverse demonstration projects were highlighted as potential success factors for the adoption of NbS in EA.

Trypanosoma brucei occupies distinct niches throughout its life cycle, within both the mammalian and tsetse fly hosts. The immunological and biochemical complexity and variability of each of these environments require a reshaping of the protein landscape of the parasite both to evade surveillance and face changing metabolic demands. In kinetoplastid protozoa, including T. brucei, posttranscriptional control mechanisms are the primary means of gene regulation, and these are often mediated by RNA-binding proteins. DRBD18 is a T. brucei RNA-binding protein that reportedly interacts with ribosomal proteins and translation factors. Here, we tested a role for DRBD18 in translational control. We validate the DRBD18 interaction with translating ribosomes and the translation initiation factor, eIF3a. We further show that DRBD18 depletion by RNA interference leads to altered polysomal profiles with a specific depletion of heavy polysomes. Ribosome profiling analysis reveals that 101 transcripts change in translational efficiency (TE) upon DRBD18 depletion: 41 exhibit decreased TE and 60 exhibit increased TE. A further 66 transcripts are buffered, that is, changes in transcript abundance are compensated by changes in TE such that the total translational output is expected not to change. In DRBD18-depleted cells, a set of transcripts that codes for procyclic form-specific proteins is translationally repressed while, conversely, transcripts that code for bloodstream form- and metacyclic form-specific proteins are translationally enhanced. RNA immunoprecipitation/qRT-PCR indicates that DRBD18 associates with members of both repressed and enhanced cohorts. These data suggest that DRBD18 contributes to the maintenance of the procyclic state through both positive and negative translational control of specific mRNAs.

The heat released from the disposal of High-Heat-Generating Waste (HHGW) in a Geological Disposal Facility (GDF) will result in an increase in temperature, and therefore thermal expansion of both the engineering materials and surrounding rocks. The changes to the stress state arising from the thermal expansion of these materials, restrained by the surrounding rock mass, could affect several of the Thermal, Hydraulic, and Mechanical (THM) processes that operate after closure of a GDF. In this paper a methodology is described which suggests how the influence of thermal stress on fracture aperture around a GDF can be evaluated. A set of calculations on an illustrative Discrete Fracture Network (DFN) are reported. These calculations estimate the responses of the fractures to changes in rock stress, considering changes in fracture aperture and the resultant changes to effective intrinsic permeability.

Abstract Graphite has been used historically in nuclear reactor cores for its excellent neutron moderation properties. However, the complex material behaviour inherent in irradiated graphite has resulted in several structural integrity challenges that has constrained the lifetime of the reactor core. Working towards understanding how graphite behaves in irradiated core conditions and its safety performance has allowed for the successful life extension of the UK Advanced Gas-cooled Reactors (AGR) fleet to operate beyond their original design limits. Some of the key challenges with graphite is that due to its polycrystalline nature, the material behaviour is complex which is compounded when considering the irradiated environment; where degradation changes the material behaviour, leading to differential shrinkage and significant tensile stresses. This in turn affects the structural performance and thermal hydraulics, all of which have a consequence to the safe operation of the reactor core. Therefore, serious consideration of graphite in the design of next generation reactors will not only primarily secure safety in the design but could also reduce cost and increase the return on investment. Here, we identify seven main considerations for graphite in the design, qualification and operation of advanced reactor cores that will not only aid in meeting design code requirements (specifically ASME III Division 5) and regulator conformance, but will also improve the commercial viability of future nuclear power.