[en] Highlights: • The validated high-fidelity model for cylinder-cylinder intersection problems has been made more comprehensive. • The key load variables have been examined and their influences quantified. • Stress analysis and limit load calculations have been completed • The effect of the internal crotch corner fillet on the stress values is more effective than the external fillet effect. • For nozzle groups, the stresses decrease with the increase in ligament distance The finite element method is the most commonly used approach when solving complex practical cylinder-cylinder junctions in pressure vessels. This is used when the geometrical arrangement is out with the permitted scope of the design-by-rule approaches or when detailed stress information is required as in a fatigue assessment. High-stress concentrations occur on the crotch corner for cylinder-cylinder joints, and it is possible to reach solutions for this problem by using both theoretical and numerical solutions. However, those approaches do not fully overlap nor have the same underlying assumptions. As such, an innovative high-fidelity finite element model has been developed to provide a holistic unified approach which can tackle a wide range of problems. In this study, various detailed nozzle design challenges were investigated including single and multiple nozzle combinations, nozzle-cylinder systems with different size ratios, fillet weld applications, limit loads and external loading cases were analyzed. The results obtained are compared with well-respected calculation methods such as WRC537, and a new approach is presented for the analysis of cylinder-cylinder combinations.

[en] External dosimetry audit is valuable for the assurance of radiotherapy quality. However, motion management has not been rigorously audited, despite its complexity and importance for accuracy. We describe the first end-to-end dosimetry audit for non-SABR (stereotactic ablative body radiotherapy) lung treatments, measuring dose accumulation in a moving target, and assessing adequacy of target dose coverage.

[en] Purpose: To make an adaptable, head shaped radionuclide phantom to simulate molecular imaging of the brain using clinical acquisition and reconstruction protocols. This will allow the characterization and correction of scanner characteristics, and improve the accuracy of clinical image analysis, including the application of databases of normal subjects. Methods: A fused deposition modeling 3D printer was used to create a head shaped phantom made up of transaxial slabs, derived from a simulated MRI dataset. The attenuation of the printed polylactide (PLA), measured by means of the Hounsfield unit on CT scanning, was set to match that of the brain by adjusting the proportion of plastic filament and air (fill ratio). Transmission measurements were made to verify the attenuation of the printed slabs. The radionuclide distribution within the phantom was created by adding ^99mTc pertechnetate to the ink cartridge of a paper printer and printing images of gray and white matter anatomy, segmented from the same MRI data. The complete subresolution sandwich phantom was assembled from alternate 3D printed slabs and radioactive paper sheets, and then imaged on a dual headed gamma camera to simulate an HMPAO SPECT scan. Results: Reconstructions of phantom scans successfully used automated ellipse fitting to apply attenuation correction. This removed the variability inherent in manual application of attenuation correction and registration inherent in existing cylindrical phantom designs. The resulting images were assessed visually and by count profiles and found to be similar to those from an existing elliptical PMMA phantom. Conclusions: The authors have demonstrated the ability to create physically realistic HMPAO SPECT simulations using a novel head-shaped 3D printed subresolution sandwich method phantom. The phantom can be used to validate all neurological SPECT imaging applications. A simple modification of the phantom design to use thinner slabs would make it suitable for use in PET.

[en] Highlights: • Joint strength and sealing performance of a gasketed bolted flanged studied. • Under bolt up and combined operating conditions using 3D nonlinear FEA. • Strength of joint is affected by the axial and thermal loading combination. • Joint sealing is dependent on the bolt up strategy during assembly and is slightly affected under pressure. • Thermal loading has a significant effect on the sealing performance up to 100 °C. In this paper the strength and sealing performance of a gasketed bolted flanged pipe joint is studied under bolt up and combined operating conditions using 3D nonlinear finite element analysis. The key combinations of internal pressure, axial and thermal loading are considered. The strength of the joint is seen to be affected by the axial and thermal loading combination whereas the joint sealing is seen to be dependent on the bolt up strategy during assembly and is slightly affected under pressure but only partially affected under axial loading in certain locations. Thermal loading was also considered and was found to have a significant effect on the sealing performance up to 100 °C, but beyond that no sealing was observed, resulting in the possibility of leakage and hence increasing the risk of overall joint failure. Finally, the joint load capacities are determined under various combined loadings showing its safe and unsafe operational limits.

[en] Achieving a proper preload in the bolts of a gasketed bolted flanged pipe joint during joint assembly is considered important for its optimized performance. This paper presents results of detailed non-linear finite element analysis of an optimized bolt tightening strategy of different joint sizes for achieving proper preload close to the target stress values. Industrial guidelines are considered for applying recommended target stress values with TCM (torque control method) and SCM (stretch control method) using a customized optimization algorithm. Different joint components performance is observed and discussed in detail.

[en] Single- to multiple-year drought episodes posed significant challenges for agrarian communities across southern Africa during the nineteenth century and hence are widely recorded in a variety of historical documents. However, the ways in which droughts are articulated, and the focus of individual accounts, vary considerably between different authors and historical source types. This study draws on a range of documentary source types—specifically newspapers, letters, reports and diaries—to explore the varied narratives associated with three protracted droughts (those of 1861–1863, 1876–1879 and 1895–1897) that affected large areas of the subcontinent. The analysis spans four case study areas—present day KwaZulu-Natal (South Africa), Lesotho, Malawi and the southern Kalahari (Botswana and South Africa)—which were investigated as part of different interdisciplinary projects. We explore issues common to all case study areas, including (i) how specific drought events are framed and (ii) what is and is not reported about individual droughts across different source types. We conclude that different source types in the subcontinent may be more or less appropriate for addressing the specific objectives of historical climatology, particularly in relation to historical drought. Sources such as newspapers and weather diaries are rich in qualitative and quantitative observations suitable for the reconstruction of temporal and spatial patterns of weather and climate, as well as climate-related natural disasters. In contrast, letters, reports and personal journals, especially those written by missionaries, provide additional qualitative narratives through which to investigate the vulnerability of past societies and economies to climate variations, and to explore past discourses and social representations of climate. While studies of this kind have been published for European and American source types, this is the first systematic exploration of documentary sources for the historical climatology of Africa. It should therefore provide a guide for climate history studies elsewhere in the continent, or other regions where written records are absent prior to the arrival of European colonists.

[en] Highlights: • Sediment properties and structure differ in relation to the former land use. • Anoxic conditions only detected at site with highest sediment accretion rate. • Poor drainage is caused by the lack of interaction between sediment facies. • Findings important for predicting the delivery of ecosystem services in future sites. -- Abstract: Managed realignment (MR) schemes are being implemented to compensate for the loss of intertidal saltmarsh habitats by breaching flood defences and inundating the formerly defended coastal hinterland. However, studies have shown that MR sites have lower biodiversity than anticipated, which has been linked with anoxia and poor drainage resulting from compaction and the collapse of sediment pore space caused by the site's former terrestrial land use. Despite this proposed link between biodiversity and soil structure, the evolution of the sediment sub-surface following site inundation has rarely been examined, particularly over the early stages of the terrestrial to marine or estuarine transition. This paper presents a novel combination of broad- and intensive-scale analysis of the sub-surface evolution of the Medmerry Managed Realignment Site (West Sussex, UK) in the three years following site inundation. Repeated broad-scale sediment physiochemical datasets are analysed to assess the early changes in the sediment subsurface and the preservation of the former terrestrial surface, comparing four locations of different former land uses. Additionally, for two of these locations, high-intensity 3D-computed X-ray microtomography and Itrax micro-X-ray fluorescence spectrometry analyses are presented. Results provide new data on differences in sediment properties and structure related to the former land use, indicating that increased agricultural activity leads to increased compaction and reduced porosity. The presence of anoxic conditions, indicative of poor hydrological connectivity between the terrestrial and post-inundation intertidal sediment facies, was only detected at one site. This site has experienced the highest rate of accretion over the terrestrial surface (ca. 7 cm over 36 months), suggesting that poor drainage is caused by the interaction (or lack of) between sediment facies rather than the former land use. This has significant implications for the design of future MR sites in terms of preparing sites, their anticipated evolution, and the delivery of ecosystem services.

[en] To protect terrestrial ecosystems and humans from contaminants many countries and jurisdictions have developed soil quality guidelines (SQGs). This study proposes a new framework to derive SQGs and guidelines for amended soils and uses a case study based on phytotoxicity data of copper (Cu) and zinc (Zn) from field studies to illustrate how the framework could be applied. The proposed framework uses normalisation relationships to account for the effects of soil properties on toxicity data followed by a species sensitivity distribution (SSD) method to calculate a soil added contaminant limit (soil ACL) for a standard soil. The normalisation equations are then used to calculate soil ACLs for other soils. A soil amendment availability factor (SAAF) is then calculated as the toxicity and bioavailability of pure contaminants and contaminants in amendments can be different. The SAAF is used to modify soil ACLs to ACLs for amended soils. The framework was then used to calculate soil ACLs for copper (Cu) and zinc (Zn). For soils with pH of 4-8 and OC content of 1-6%, the ACLs range from 8 mg/kg to 970 mg/kg added Cu. The SAAF for Cu was pH dependant and varied from 1.44 at pH 4 to 2.15 at pH 8. For soils with pH of 4-8 and OC content of 1-6%, the ACLs for amended soils range from 11 mg/kg to 2080 mg/kg added Cu. For soils with pH of 4-8 and a CEC from 5-60, the ACLs for Zn ranged from 21 to 1470 mg/kg added Zn. A SAAF of one was used for Zn as it concentrations in plant tissue and soil to water partitioning showed no difference between biosolids and soluble Zn salt treatments, indicating that Zn from biosolids and Zn salts are equally bioavailable to plants

[en] Laboratory-based relationships that model the phytotoxicity of metals using soil properties have been developed. This paper presents the first field-based phytotoxicity relationships. Wheat (Triticum aestivum L.) was grown at 11 Australian field sites at which soil was spiked with copper (Cu) and zinc (Zn) salts. Toxicity was measured as inhibition of plant growth at 8 weeks and grain yield at harvest. The added Cu and Zn EC10 values for both endpoints ranged from approximately 3 to 4760 mg/kg. There were no relationships between field-based 8-week biomass and grain yield toxicity values for either metal. Cu toxicity was best modelled using pH and organic carbon content while Zn toxicity was best modelled using pH and the cation exchange capacity. The best relationships estimated toxicity within a factor of two of measured values. Laboratory-based phytotoxicity relationships could not accurately predict field-based phytotoxicity responses. - Field-based toxicity of Cu and Zn to wheat can be modelled using soil properties. Laboratory-based models should not be used to estimate toxicity in the field

[en] For essential elements, such as copper (Cu) and zinc (Zn), the bioavailability in biosolids is important from a nutrient release and a potential contamination perspective. Most ecotoxicity studies are done using metal salts and it has been argued that the bioavailability of metals in biosolids can be different to that of metal salts. We compared the bioavailability of Cu and Zn in biosolids with those of metal salts in the same soils using twelve Australian field trials. Three different measures of bioavailability were assessed: soil solution extraction, CaCl₂ extractable fractions and plant uptake. The results showed that bioavailability for Zn was similar in biosolid and salt treatments. For Cu, the results were inconclusive due to strong Cu homeostasis in plants and dissolved organic matter interference in extractable measures. We therefore recommend using isotope dilution methods to assess differences in Cu availability between biosolid and salt treatments. - Metals in biosolids are not necessarily less bioavailable than their soluble salt.