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Abstract Subcooled flow boiling is frequently encountered in hot assemblies in nuclear power plant. Considerable efforts have been made to improve the understanding of boiling process and prediction of critical heat flux (CHF). In this study, the effects of non-uniform heat input on heat transfer characteristics are further investigated, so that more realistic descriptions of practical systems can be achieved vis-a-vis usual heat input assumptions. A CFD model has been built to predict subcooled flow boiling process in a vertical round pipe. The capability of the model is validated against experimental results in the publication. A variety of non-uniform heat input profiles are tested using this validated CFD model. Results show that a regular triangle-shape heat input profile will cause stronger vapour generation in the middle of the heating region. Also, the risk of reaching CHF may be increased with the position of maximum heat flux moving downstream.

The decarbonisation of heating in the United Kingdom is likely to entail both the mass adoption of heat pumps and widespread development of district heating infrastructure. Estimation of the spatially disaggregated heat demand is needed for both electrical distribution network with electrified heating and for the development of district heating. The temporal variation of heat demand is important when considering the operation of district heating, thermal energy storage and electrical grid storage. The difference between the national and urban heat demands profiles will vary due to the type and occupancy of buildings leading to temporal variations which have not been widely surveyed. This paper develops a high-resolution spatiotemporal heat load model for Great Britain (GB: England, Scotland a Wales) by identifying the appropriate datasets, archetype segmentation and characterisation for the domestic and nondomestic building stock. This is applied to a thermal model and calibrated on the local scale using gas consumption statistics. The annual GB heat demand was in close agreement with other estimates and the peak demand was 219 GWth. The urban heat demand was found to have a lower peak to trough ratio than the average national demand profile. This will have important implications for the uptake of heating technologies and design of district heating.

The monitoring of a waste separation process in the nuclear power industry is considered. Recent advances in gamma ray emission and electrical impedance tomography mean that it is now feasible to unite these two modalities into a novel dual-modality monitoring method. This paper considers a simple model problem for the identification of a boundary between two distinct waste streams in a semi-continuous rotation separator. The simplicity of the problem affords the opportunity to demonstrate the general feasibility of the approach whilst avoiding unnecessary complications.

Effects of nicotine, administered by continuous infusion via osmotic minipumps, were studied on the operant self-administration of alcohol by rats, using a variable interval (15 s) schedule, and measuring the acquisition, maintenance, extinction and reinstatement of responding for alcohol. Doses of nicotine of 0.25, 1.25 and 7.5 mg/kg/24 h had no significant effects on the maintenance of responding for alcohol, but 5 mg/kg/24 h nicotine resulted in a significant increase in responding on the lever delivering the reward when water was substituted for the alcohol, indicating delayed extinction of responding. During infusion of 2.5 mg/kg/24 h nicotine, responding was significantly greater over the "sucrose-fading" training sessions, during acquisition of responding, when mixtures of alcohol and sucrose were provided as reward. When minipumps infusing 2.5 mg/kg/24 h nicotine were implanted after the alcohol responding had been acquired, the responding for alcohol increase during the first week of nicotine infusion, but corresponding nicotine infusion doses of 0.25, 1.25 and 7.5 had no significant effects. The results indicate that nicotine can increase operant responding for alcohol and this is crucially dependent on the dose of nicotine and the time of testing. The results have implications for the frequently encountered dependence on the combination of alcohol and nicotine.

The capillary effect has wide applications from biology and textile engineering to nanotechnology especially the micro-electromechanical systems and microfluidics device. The capillary vibration significantly affects its mass transmission. This paper establishes a nonlinear oscillator of a deforming capillary tube. The geometric potential theory is used to estimate the capillary force. The paper reveals that the low-frequency property of capillary vibration plays an important role not only in life but also engineering applications.

Abstract The determination of extremely low probability of the reactor pressure vessel and the primary main coolant pipe fracture is one of the prerequisites for further operation of the first generation NPPs in Czechoslovakia. The project for this task includes experimental and analytical work on the reactor pressure vessel and on the main piping components. Review of the project and preliminary results are presented. The results show extremely low probability of failure. Future work is focussed on annealing studies and tests for the pressure vessel and the application of the Leak-Before-Break technology on primary piping circuit.

This work addresses the problem of energy consumption time series forecasting. In our approach, a set of time series containing energy consumption data is used to train a single, parameterised prediction model that can be used to predict future values for all the input time series. As a result, the proposed method is able to learn the common behaviour of all time series in the set (i.e., a fingerprint) and use this knowledge to perform the prediction task, and to explain this common behaviour as an algebraic formula. To that end, we use symbolic regression methods trained with both single- and multi-objective algorithms. Experimental results validate this approach to learn and model shared properties of different time series, which can then be used to obtain a generalised regression model encapsulating the global behaviour of different energy consumption time series.

Abstract Despite multiple studies of the impact of climate change on temperate tree species, experiments on tropical and economically important tree crops, such as cacao (Theobroma cacao L.), are still limited. Here, we investigated the combined effects of increased temperature and atmospheric carbon dioxide concentration ([CO2]) on the growth, photosynthesis and development of juvenile plants of two contrasting cacao genotypes: SCA 6 and PA 107. The factorial growth chamber experiment combined two [CO2] treatments (410 and 700 p.p.m.) and three day/night temperature regimes (control: 31/22 °C, control + 2.5 °C: 33.5/24.5 °C and control + 5.0 °C: 36/27 °C) at a constant vapour pressure deficit (VPD) of 0.9 kPa. At elevated [CO2], the final dry weight and the total and individual leaf areas increased in both genotypes, while the duration for individual leaf expansion declined in PA 107. For both genotypes, elevated [CO2] also improved light-saturated net photosynthesis (Pn) and intrinsic water-use efficiency (iWUE), whereas leaf transpiration (E) and stomatal conductance (gs) decreased. Under a constant low VPD, increasing temperatures above 31/22 °C enhanced the rates of Pn, E and gs in both genotypes, suggesting that photosynthesis responds positively to higher temperatures than previously reported for cacao. However, dry weight and the total and individual leaf areas declined with increases in temperature, which was more evident in SCA 6 than PA 107, suggesting the latter genotype was more tolerant to elevated temperature. Our results suggest that the combined effect of elevated [CO2] and temperature is likely to improve the early growth of high temperature-tolerant genotypes, while elevated [CO2] appeared to ameliorate the negative effects of increased temperatures on growth parameters of more sensitive material. The evident genotypic variation observed in this study demonstrates the scope to select and breed cacao varieties capable of adapting to future climate change scenarios.